• 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.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.489-497
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• 2000

Since Chinese cabbages weigh 3 to 5kgf and are big in size at the time of harvest, handling operations such as harvesting, loading and unloading including transportation require the highest labor demand among all other cultivation processes. Recently, though several cabbage harvesters were developed in Japan and Europe, those harvesters were not suitable for Chinese cabbages cultivated in Korea because of the size and shape. The cabbage harvester is almost meaningless without any proper cabbage piling and pallet unloading mechanism. Most harvesters developed so far adopted a sort of slide and free falling way in collecting cabbages into the pallet. Three or four labors are usually required for cleaning incoming cabbages and loading those in the pallet. Because of the required time for piling cabbages without severe damage and the required space capacity to carry empty and loaded pallets, harvesting speed should be adjusted in accordance with time required for consecutive operations. Up to now, any automatic or semi-automatic collecting device has not been developed in the world to pile cabbages on the layer one by one into the pallet in the ordered way with little damage and to unload pallet from the harvester continuously during the harvest process. To compromise system expenses and function, Semi-automatic cabbage piling and pallet unloading mechanism was devised and it required one labor. The foldable mesh pallet with a size of 1050mm x 1050mm x 1000mm and holding capacity of around 70 cabbages was utilized. The prototype for piling and unloading mechanism was composed of three parts such as feeding device, automatic piling device with retractable bellows, and pallet unloading device. Prior to developing the prototype, the geometric properties and the amount of the damage of the cabbage caused during the piling operation were investigated. Considering the height of the pallet, a series of cabbage carrying plates were mounted to the bracket chain to lift and to carry cabbages to the loading device. Indoor laboratory experiments showed that the cabbage carrying chain conveyor worked successfully. Considering the conveying speed 0.46m/sec of the pull up belt from the cabbages on the ground, the speed of cabbage carrying chain conveyor worked property in the range of 0.26m/sec to 0.36m/sec. The system allowed the operator to modify the position of cabbage slightly. Overall system worked successfully resulting into almost same capacity without severe damage to the cabbage as human did.

• Tribology and Lubricants
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• 제32권2호
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• pp.50-55
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• 2016

Recently, a double-side machining process has been adopted in fabricating a sapphire glass to enhance the manufacturability. Double-side lap grinding (DLG) is one of the emerging processes that can reduce process steps in the fabrication of sapphire glasses. The DLG process uses two-body abrasion with fixed abrasives including pallet. This process is designed to have a low pressure and high rotational speed in order to obtain the required material removal rate. Thus, the temperature is distributed on the DLG platen during the process. This distribution affects the shape of the substrate after the DLG process. The coolant that is supplied into the cooling channel carved in the base platen can help to control the temperature distribution of the DLG platen. This paper presents the results of computational fluid dynamics with regard to the heat transfer in a DLG platen, which can be used for fabricating a sapphire glass. The simulation conditions were 200 rpm of rotational speed, 50℃ of frictional temperature on the pallet, and 20℃ of coolant temperature. The five cases of the coolant flow rate (20~36 l/min) were simulated with a tetrahedral mesh and prism mesh. The simulation results show that the capacity of the generated cooling system can be used for newly developed DLG machines. Moreover, the simulation results may provide a process parameter influencing the uniformity of the sapphire glass in the DLG process.

• Journal of the Korean Wood Science and Technology
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• 제52권5호
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• pp.423-437
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• 2024

Wood biomass, such as sawdust, particles, and chips from the wood industry, can be potentially used as a composite product. Chip block pallets (CBP) are composite products that can be produced from industrial wood waste and are in high demand in the logistics sector. Therefore, this study aimed to investigate the production of CBP from teak wood biomass with varying polyurethane contents. In addition, this study analyzed the optimum particle-size composition was determined. The CBP production of CBP be divided into two stages. The first stage evaluated the use of polyurethane adhesive content, whereas the second stage considered the effect of particle size composition. The 9 × 9 × 9 cm³ of CBP with 0.6 g/cm³ target density was fabricated using a cold press. The National Wooden Pallet and Container Association (NWPCA) standards were used to evaluate the density, moisture content, dimensional stability, water absorption, compressive strength (CS), and screw-holding strength (SHS) of our CBP products. The mechanical and physical properties of CBP products were investigated. As a result, the CBP sample prepared using 4-14 mesh particle size and 4.5% adhesive content showed the optimal strength values, such as CS of 14.67 MPa and SHS of 371.50 N. These findings demonstrate that the CBPs derived from teak wood waste closely resemble commercial chip blocks and have the potential to replace wood bearings as pallet pads.

• 한국포장학회지
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• 제30권2호
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• pp.141-147
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• 2024

스마트 농산물산지유통센터(APC) 도입에 따라 인력 작업 체계를 기계화하고, 양파 수확 작업의 저비용 및 고효율화와 장기 저장을 위해 그물망 대신 톤백(TB)과 와이어메쉬파레트(WMP)로 포장하고 적재하여 저장하는 동안 양파의 수분함량, 경도, 색도, 가용성 고형분 함량, 관능 검사 등 저장성을 비교 분석하였다. 대조군과 비교했을 때 TB와 WMP를 사용한 경우 수분함량, 가용성 고형분 함량, 경도, 색도에서 유의적 차이가 관찰되지 않았다. 외관 변화에 있어 TB는 CON과 비교 시 큰 차이가 없음을 확인하였다. 이는 그물망을 대체하여 TB로 양파를 포장하고 적재 및 저장하는 것이 양파 수확 작업 시 저비용 및 고효율화하고 스마트APC의 공정 개선에 효율적으로 적용할 수 있을 것으로 검토되었다.

• Journal of Biosystems Engineering
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• 제27권3호
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• pp.211-218
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• 2002

배추 생산에 있어서 수확, 운반, 적재 작업은 가장 노동이 집약적으로 요구되는 작업들이다. 최근, 여러 종류의 양배추 수화기가 일본과 유럽에서 개발되었다. 하지만 국내에서 재래되는 배추는 크기와 형태에 있어 양배추와는 달라 기 개발 기종의 도입이 어렵다. 또한 수확작업의 생력화 효과는 운반, 정선, 적재 작업과 밀접하게 연계되어 있어 출하시의 작업체계를 고려하여 수화에 따른 수집.반출 시스템을 개발하여야 한다. 수확시의 배추는 중량이 25~45 N 정도로 다 작물에 비하여 무겁고 부피가 크기 때문에 수확작업의 기계화를 위해서는 수확장치와 더불어 연속적으로 수확되는 배추를 적절하게 수집하여 적재하고 반출하는 시스템의 개발이 중요하다. 본 연구에서는 수확작업의 생력화 효과를 높이고 생력화 시스템 비용의 절감을 목적으로 작업자 1인에 의해 작업할 수 있는 반자동 형태의 트랙터 부착형 배추 수집, 적재, 반출시스템 시작기를 개발하였다. 시작기는 배추 이송장치, 적재장치, 팔렛 및 반출장치의 3개 부분과 PLC를 이용한 주 제어기로 구성하였다. 배추 수집용기로는 대략 70개의 배추를 담을 수 있는 크기가 1,050 mm$\times$1.050mm$\times$1,000mm 인 접이식 메쉬 팔렛을 사용하였으며 하단부에 롤러 안내판을 부착하여 적재한 팔렛의 배출이 용이하도록 하였다. 팔렛을 제외한 전체 시작기의 중량은 235 N 이였으며 크기는 3,940mm$\times$520mm$\times$1,630mm 이었다. 본 연구는 수확장치의 기능 및 생력화 효과를 극대화하고 배추의 손상정도를 최소화하는 시스템을 구성하고자 하였다. 이송장치는 트랙터 부착시 횡공간 점유율을 최소화하도록 하였으며 적재장치는 적재시 배추의 손상을 줄이고 배추가 놓이는 자세를 능동적으로 조절할 수 있도록 주름관을 부착하였다. 시작기의 실내시험 결과 이송장치는 0.18 m/s~0.36 m/s의 범위에서 적재장치는 0.4 m/s~2.4 m/s 범위에서 안정적으로 구동하였으며 두 장치를 동시에 구동하여 시험한 결과 이송장치는 0.26 m/s~0.36 m/s, 그리고 적재장치는 0.9 m/s~2.4 m/s 에서 적정하게 안정적으로 구동하였다. 적재장치의 성능에 있어서 1~3단 적재시에는 주름관을 이용하여 적재하고 4~5단 적재시에는 자유낙하에 의한 적재를 수행할 경우 인력에 의한 적재와 거의 동등한 적재량을 보였으며 손상정도는 거의 무시할 정도였다. 트랙터가 0.3 m/s로 주행하는 경우 노지로부터 배추를 뽑아 이송하는 뽑기벨트의 적정속도가 0.46 m/s인 점을 고려할 때 배추 이송 컨베이어는 0.34 m/s 이상의 속도를 유지할 필요가 있었으며 적재 컨베이어는 2 m/s~2.4 m/s의 속도에서 안정적으로 작동하였다. 배추의 주간 거리가 대략 30~40 cm 인 점을 감안하면 적재장치는 초당 1개의 적재성능을 보였다. 실내에서 수행한 시스템의 성능은 배추에 큰 손상없이 전반적으로 성공적으로 구동하였으나 향후 노면이 고르지 못한 포장에서의 성능 시험이 필요하다.