• 한국작물학회지
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• 제56권4호
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• pp.400-403
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• 2011

고구마 수확단계에서 작업체계에 따른 생력효과를 조사하고자 순치기와 1열식과 2열식 수확기를 이용하여 시험을 수행한 결과를 요약하면 다음과 같았다. 1. 고구마 수확단계 작업체계는 순치기+비닐제거+2열식 기계수확 +인력굴취가 ha당 106.4시간, 순치기+비닐제거+1열식 기계수확 +인력굴취가 ha당 111.3시간 및 순치기와 비닐제거 작업을 생략하고 1열식 기계수확+인력굴취가 당 107.6시간으로 관행(인력 333.2시간/ha) 대비 각각 68.1%, 66.6% 및 66.8%의 생력효과가 있었다. 2. 고구마 손상개수율은 인력수확이 8.6%인데 비해 기계 2열식이 4.4%, 기계1열식이 5.3%로 약 43.9%가 적게 발생되었으며, 품종에 손상개수율은 연미 6.2%, 신천미5.1%, 하얀미 4.7%, 건미 3.4% 순으로 차이가 있었다. 3. 수확단계 비용절감효과는 ha당 고구마 손상개수율을 포함한 수확단계의 비용이 관행(인력) 2,963천원에 비해 고구마 순치기와 수확기의 이용에 의해 62.9~81.2%인 1,865~2,406천원 절감되었다.

• Composites Research
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• 제37권2호
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• pp.139-142
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• 2024

This study explores the impact of polymer blending on the mechanical properties and triboelectric energy harvesting capability of composite polymers. A multifunctional free-standing polymer blend composed of poly(vinyl alcohol) (PVA) and poly(diallyldimethylammonium chloride) (PDDA) was fabricated using a polymer casting method. Stress-strain analysis of the polymer blend revealed an enhanced stretchability of 308.4% with excellent transparency. Furthermore, triboelectric analysis revealed dynamic energy harvesting capabilities with impressive electrical voltage and current output of 50 V and 5 μA. These results represent a significant improvement compared to individual PVA and PDDA polymers and highlight the potential of polymer blending to enhance both mechanical and electrical properties for energy harvesting applications.

• 한국농공학회지
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• 제17권2호
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• pp.3772-3777
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• 1975

This paper reports on the analysis of the distributions of probable days being good for mechanical rice harvesting and the method of determining the capacity of rice harvesting machinery for the given harvesting duration. In the analysis of the probability distribution of days being good for rice harvesting, the daily rainfalls above which mechanical field work may be impracticable were specified and their frequency of occurances was analyzed by using the weather records during past twenty-one years measured at five different locations. The conclusions being drawn from the analysis are as follows: 1. The distributions of probable workable days in different region and harvesting duration are very distinct and are different to set a uniform trend (refer to Fig. 1-4). 2. The occurance of probable days being good for mechanical field work under 66% confidence level are quite variable by region and by ten-day period. The analysis indicates that the probable workable days may range from 7.5 to 8.5 days of 10-day span within optimum harvesting duration (refer to Table 1). 3. Based on the probability distributions analyzed, the optimun capacities of harvesting machinery required for different harvesting areas and harvesting start-date were estimated as a function of operating duration (refer to Fig. 5 and Table 2)

• 한국식품저장유통학회지
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• 제30권5호
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• pp.811-821
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• 2023

본 연구는 인력수확과 기계수확 즉, 수확 방법을 달리한 양파와 기계수확 과정에서 발생되는 양파와 양파 간 충격을 모의하여 인위적으로 충격처리 한 양파의 품질 및 저장성을 평가하여 기계수확을 위한 자료를 얻고자 하였다. 수확방법은 인력굴취 후 인력수집, 기계굴취 후 인력수집, 기계굴취 후 기계수집 총 3가지였다. 그리고 본 연구의 굴취 및 수집과정에서의 최고 충격 높이는 0.5 m였다. 수확 직후 압상률과 상해율은 수확 방법 간 유의한 차이가 없었다. 만약 기계수확으로 압상이나 상해 발생이 증가한다면 그 원인은 토양에 함유된 자갈 등의 토양 조건과 속도 등의 기계 운전 조건이 영향을 미친 것으로 사료된다. 또한, 저장 8.5개월 동안의 품질 및 저장성도 수확 방법 간에 차이가 나타나지 않았다. 모의 충격실험은 0.0 m(0.0 J), 0.25 m(0.86 J), 0.5 m(1.72 J), 0.75 m(2.57 J)에서 1회 처리와 0.25 m에서 동일위치 4회(3.43 J)와 다른위치 4회(3.43 J)를 pendulum 방식으로 충격처리하여 저장성을 조사하였다. 모든 처리에서 저장 8.5개월 동안 품질과 저장성은 처리 간에 유의한 차이가 나타나지 않았다. 결론적으로 본 연구의 양파 기계수확은 인력수확과 품질 및 저장성에서 차이가 없었고, 기계수확을 모의한 충격처리도 양파의 품질 및 저장성에 거의 영향을 미치지 않는 것으로 나타났다. 이는 수확 기계의 제작과 기계수확 시 운전 조건에 대한 자료를 제공함으로써 향후 양파 수확 작업의 기계화 확대에 도움이 될 수 있을 것으로 기대된다.

• Journal of Biosystems Engineering
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• 제35권6호
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• pp.367-372
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• 2010

Consumption of pepper, a major spice vegetable used for seasoning Kimchi, continues to increase, but cultivation is in decline due to shortage of rural labor in Korea. The 39.2% of total labor requirement for conventional pepper cultivation was available for harvesting work. Therefore conventional manual harvesting should be turned to mechanical harvesting for labor-saving, cost-reducing and easy work. Surveys on conventional pepper cultivation patterns, labor requirements for various pepper cultivation works, and farmers' opinions on the mechanization of pepper harvesting were conducted to obtain basic informations. The labor requirement for pepper harvesting was 954 h/ha out of a total labor requirement of 2,436 h/ha for pepper cultivation. Harvesting was the hardest work, and hiring workmen for harvesting was also difficult. Farmers preferred to develop a small-scale pepper harvester using agricultural tractor or cultivar. Most farmer agreed to change cultivation pattern for mechanization of pepper harvesting, but hesitated to adopt new one-time-harvesting pepper varieties.

• 한국작물학회지
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• 제54권1호
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• pp.7-12
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• 2009

녹두는 생리적 특성과 재배지역의 기상조건 등에 따라 여러 번 수확해야한다. 한국에서는 일반적으로 6월에 파종하여 $3{\sim}4$회 가량 수확하므로 녹두 재배면적이 급격히 감소하고 있다. 따라서 한국 남부지역의 기상조건에 맞는 기계수확 재배기술을 개발하고자 본 연구를 수행하였다. 남부지역에서 기계수확을 위한 최적 파종기는 7월 20일 경 이었다. 7월 15일 경에 파종하였을 때는 2회 수확해야 하므로 기계수확이 불가능하였다. 7월 25일 이후 파종하였을 때는 기계수확이 가능하였으나 성숙기간이 길어지고 수량이 적었다. 그러므로 한국에서는 남부지역 7월 20일 기준으로 중부지역은 이전에 남부해안지역은 이후에 파종하면 녹두 기계수확이 가능할 것으로 보아진다. 한국에 가장 많이 보급된 금성녹두와 어울녹두 중에 어울녹두가 기계수확 재배에 적합한 품종이었다. 즉 어울녹두는 금성녹두에 비해 경장이 길고 착협고가 높아 기계수확에 유리할 뿐만 아니라 수량이 많았다.

• 센서학회지
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• 제32권4호
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• pp.213-218
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• 2023

Triboelectric nanogenerators (TENGs) have emerged as a highly promising energy harvesting technology capable of harnessing mechanical energy from various environmental vibrations. Their versatility in material selection and efficient conversion of mechanical energy into electric energy make them particularly attractive. TENGs can serve as a valuable technology for self-powered sensor operation in preparation for the IoT era. Additionally, they demonstrate potential for diverse applications, including energy sources for implanted medical devices (IMDs), neural therapy, and wound healing. In this review, we summarize the potential use of this universally applicable triboelectric energy harvesting technology in the disinfection and blocking of pathogens. By integrating triboelectric energy harvesting technology into human clothing, masks, and other accessories, we propose the possibility of blocking pathogens, along with technologies for removing airborne or waterborne infectious agents. Through this, we suggest that triboelectric energy harvesting technology could be an efficient alternative to existing pathogen removal technologies in the future.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.294-303
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• 2016

Purpose: This study aimed to evaluate the profitability of four selective mechanization systems in rice cultivation. Methods: Field experiments were conducted in the farmers' field during the wet season (June to November) of 2015 in Bangladesh. Mechanization systems were applied to evaluate four different selective levels (treatment) in eleven consequent operations. Seedlings were raised in a traditional seedbed and trays for manual and mechanical transplanting, respectively. Land preparation, irrigation, fertilizer, pesticide, carrying, and threshing and cleaning operations were performed using the same method in all the experimental plots. The mechanical options in the transplanting, weeding, and harvesting operations were changed. The mechanization systems were $S_1$ = hand transplanting + hand weeding + harvesting by sickle, $S_2$ = mechanical transplanting + Bangladesh Rice Research Institute (BRRI) weeder + reaper, $S_3$ = mechanical transplanting + BRRI power weeder + reaper, and $S_4$ = mechanical transplanting + herbicide + reaper. This experiment was performed in a randomized complete block design with four replications. Power tiller, rice transplanter, BRRI weeder, BRRI power weeder, self-propelled reaper, BRRI open drum thresher, and BRRI winnower were used in the respective operations. Accordingly, the techno-economic performances of the different technologies were calculated and compared with those of the traditional system. Results: The mechanically transplanted plot produced 6-10% more yield than the hand transplanted plot because of the use of tender-aged seedlings. Mechanical transplanting reduced 61% labor and 18% cost compared to manual transplanting. The BRRI weeder, BRRI power weeder, and herbicide application reduced 74, 91, and 98% labor, respectively. The latter also saved 72, 63, and 82% cost, respectively, compared to hand weeding. Herbicide application reduced the substantial amount of labor and cost in the weeding operation. Mechanical harvesting also saved 96% labor and 72% cost compared to the traditional method of harvesting using sickle. Selective mechanization saved 15-17% input cost compared to the traditional method of rice cultivation. Conclusions: Mechanical transplanting with the safe use of herbicide and harvesting by reaper is the most cost- and labor-saving operation. The method might be the recommended set of selective mechanization for enhancing productivity.

• Smart Structures and Systems
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• 제33권4호
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• pp.281-290
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• 2024

This work investigates the mechanical energy harvesting from smart and adaptive devices using magnetic interactions. The energy harvester is built from an elastic beam connected to an electric circuit by a magnetostrictive material that promotes energy transduction. Besides, magnetic interactions define the system stability characterizing multistable configurations. The adaptiveness is provided by magnets that can change their position with respect to the beam, changing the system configuration. A mathematical model is proposed considering a novel model to describe magnetic interactions based on the single-point magnet dipole method, but employing multiple points to represent the magnetic dipole, which is more effective to match experimental data. The adaptive behavior allows one to alter the system stability and therefore, its dynamical response. A nonlinear dynamics analysis is performed showing the possibilities to enhance energy harvesting capacity from the magnet position change. The strategy is to perform a system dynamical characterization and afterward, alter the energetic barrier according to the environmental energy sources. Results show interesting conditions where energy harvesting capacity is dramatically increased by changing the system characteristics.

• International Journal of Aerospace System Engineering
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• 제2권1호
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• pp.47-52
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• 2015

The transient phenomenon of self-powered energy-harvesting is assessed using a bond-graph method. The bond-graph is an energy-based approach to describing physical-dynamic systems. It shows power flow graphically, which helps us understand the behavior of complicated systems in simple terms. Because energy-harvesting involves conversion of power in mechanical form to the electrical one, the bond-graph is a good tool to analyze this power flow. Although the bond-graph method can be used to calculate the dynamics of combining mechanical and electrical systems simultaneously, it has not been used for harvesting analysis. We demonstrate the usability and versatility of bond-graph for not only steady analysis but also transient analysis of harvesting.