• 한국자원식물학회지
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• 제15권1호
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• pp.72-76
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• 2002

지황의 수확방법을 인력수확에서 생력기계화 수확기술로 개선코자 트랙터굴취기 등 4종의 수확기기의 기계수확 효율을 비교 검토하였던 바 그 결과를 요약하면 다음과 같다. 1. 생력효율은 인력에 비하여 경운기 경운 69%, 경운기부착 굴취기 73%, 트랙터 부착 굴취기 76% 절감되었다. 2. 근경의 손실율은 인력수확 5.6%, 경운기 경운14.9%, 경운기 부착 굴취기 8.7%, 트랙터 부착 굴취기8.9%로 기계수확에서 높았다. 3. 상품 근경 수량은 인력수확 2,115 kg/10a에 비하여 기계수확에서 111~304kg/10a감소하였으며, 총 근경수량도 인력수확에 비하여 기계수확에서 2~6%감소하였다. 4. 경운기 부착 굴취기 와 트랙터 부착 굴취기 는 생력효율이 높고, 근 손상율 및 상품수량 등에서 인력수확에 크게 떨어지지 않아 적용가능성 이 높은 것으로 나타났다.

• 세라미스트
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• 제23권1호
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• pp.54-88
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• 2020

Global effort has resulted in tremendous progress with energy harvesters that extract mechanical energy from ambient sources, convert it to electrical energy, and use it for systems such as wrist watches, mobile electronic devices, wireless sensor nodes, health monitoring, and biosensors. However, harvesting a single energy source only still pauses a great challenge in driving sustainable and maintenance-free monitoring and sensing devices. Over the last few years, research on high-performance mechanical energy harvesters at the micro and nanoscale has been directed toward the development of hybrid devices that either aim to harvest mechanical energy in addition to other types of energies simultaneously or to exploit multiple mechanisms to more effectively harvest mechanical energy. Herein, we appraise the rational designs for multiple energy harvesting, specifically state-of-the-art hybrid mechanical energy harvesters that employ multiple piezoelectric and triboelectric mechanisms to efficiently harvest mechanical energy. We identify the critical material parameters and device design criteria that lead to high-performance hybrid mechanical energy harvesters. Finally, we address the future perspectives and remaining challenges in the field.

• 한국생산제조학회지
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• 제24권4호
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• pp.407-413
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• 2015

Research for renewable energy is being performed since it has the merits of little pollution of the environment and sustainable energy resources. Microalgae is attractive as a renewable energy resource. Biomass of the microalgae can be produced by mass culturing, and bulk harvest technology of is needed to produce biomass continuously. Recently, ultrasonic waves were used to harvest the cultivated microalgae continuously. In this study, the separation process using ultrasonic waves was performed to effectively harvest the microalgae. An ultrasonic wave separation resonator was designed and manufactured based on the acoustic field analysis. Separation experiments using design of experiment were carried out, and the influence of experimental variables from the ultrasonic wave separation process was investigated. Mixing conditions of variables were estimated to obtain high separation efficiency and a large microalgae harvest. Experimental results for suitable mixing conditions were compared with simulation results calculated from the state equation.

• 한국초지조사료학회지
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• 제18권3호
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• pp.259-266
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• 1998

A field experiment was carried out to determine the effects of mechanical and chemical drying agents at mowing on the field drying rate and hay quality of orchardgrass dominant pasture plants. The mower conditioner /chemical drying agent ($K_2CO_3$ 2% conditioning, $K_2CO_3$ 2% + conditioning and control) were treated at different harvest stages (late boot, heading and bloom stage) for hastening hay manufacture in 1996. After field dry, four square bales were made by hay baler, and the visual estimation and nutritive value of hay were evaluated after storing two months. The field drying rate of pasture plants was higher with delayed stage of harvest, and mechanical and mechanical + chemical, but chemical alone was very low. In mower conditioning, the duration of field dry was shortened by 0.5 to 1 day compared with $K_2CO_3$ and 1.5 to 2 days compared with control. The dry matter loss of hay was reduced by late harvest and mechanical, and mechanical + chemical, but the score by chemical alone was very low. The visual score (leafiness, green color, odor and softness) of hay after storage was high in mechanical and mechanical + chemical, but the score by chemical alone was very low. Nutritive value (ADF, NDF, digestibility, and relative feed value) of hay was also high with treatment of mechanical and mechanical + chemical, but the quality by chemical alone was similar compared with control. The quality of hay was very low when harvested at bloom stage. In conclusion, mower conditioning can enhance the field drying rate of orchardgrass dominant pasture plants, however the drying efficiency of chemical drying agent was very low. Harvesting at early heading to heading stage was recommened for manufacture of high quality hay.

• Journal of Biosystems Engineering
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• 제41권1호
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• pp.12-20
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• 2016

Purpose: Pepper prices have risen continuously because of a decrease in cultivation area; therefore, mechanical harvesting systems for peppers should be developed to reduce cost, time, and labor during harvest. In this study, a screw type picking head for a self-propelled pepper harvester was developed, and the optimal working conditions were evaluated considering helix types, winding directions of helix, and rotational speeds of the helix. Methods: The screw type was selected for the picking head after analyzing previous studies, and the device consisted of helices and a feed chain mechanism for conveying pepper branches. A double helix and a triple helix were manufactured, and rotational speeds of 200, 300, and 400 rpm were tested. The device was controlled by a variable speed (VS) motor and an inverter. Both the forward and reverse directions were tested for the winding and rotating directions of the helix. An experiment crop (cultivar: Longgreenmat) was cultivated in a plastic greenhouse. The test results were analyzed using the SAS program with ANOVA to examine the relationship between each factor and the performance of the picking head. Results: The results of the double and triple helix tests in the reverse direction showed gross harvest efficiency levels of 60-95%, mechanical damage rates of 8-20%, and net marketable portion rates of 50-80%. The dividing ratio was highest at a rotational speed of 400 rpm. Gross harvest efficiency was influenced by the types of helix and rotational speed. Net marketable portion was influenced by rotational speed but not influenced by the type of helix. Mechanical damage was not influenced by the type of helix or rotational speed. Conclusions: Best gross harvest efficiency was obtained at a rotational speed of 400 rpm; however, operating the device at that speed resulted in vibration, which should be reduced.

• 한국초지조사료학회지
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• 제19권3호
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• pp.251-258
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• 1999

본 시험은 봄철 속성건조에 의한 건조효과와 건초품질을 구명하여 양질의 건초를 조제코자, 호밀(Koolgrazer)을 공시하여 건초 조제시기(수잉후기, 출수기, 개화기)별로 건조방법(건조제, conditioning, 건조제 + conditioning, 대조구)을 달리하여 1996년 봄 수원 축산기술연구소에서 수행되었다. 화학제인 건조제는 $K_2CO_3$ 2%를 수확직전 처리하였으며, 물리적인 conditioning은 모델 GMR 2800 trail-type Mower conditioner를 사용하였다. 포장건조 후 각형 곤포를 조제하였으며, 건초의 외관평가와 사료가치는 2개 월간 보관저장 후 분석 평가하였고, 시기별 식물체의 수분 함량은 포장상태에서 양파망을 이용 조사하였다. 건조속도는 수잉후기, 출수기, 개화기로 건초 조제 시기가 늦어질수록 빨랐으며, 건조방법별로는 conditioning구와 건조제 + conditioning 구에서 우수하였고, 전반적으로 건조제 처리효과는 낮았다. conditioning 처리시 건초조제 가능일수는 수잉후기 4일, 출수기 3일, 개화기 1.5일 정도였으며, 대체로 건조제 처리구나 대조구에 비해 1일 이상 포장 건조기간 단축효과가 있었다. 건초의 건물손실은 조제시기가 늦을수록 감소하였으며, 건조방법별로는 conditioning구와 건조제 + conditioning 구에서 적었다. 건초의 외관평가에서 조제시기가 빠를수록 평점은 높았으며, 건조방법별로는 conditioning구와 건조제 + conditioning 구에서 우수하였다. 건초의 화학성분 평가에서 조제 후 저장기간중 조섬유 함량이 높아져 품질은 낮아졌으며, 대조구에 비해 conditioning구와 건조제 + conditioning 구에서 ADF와 NDF 함량이 다소 낮고 건물소화율은 약간 높은 경향을 보였다. 이상의 결과로서 호밀의 건초 조제시 포장에서의 건조기간 단축과 품질향상을 위해서는 mower conditioner 사용이 가장 바람직 하였으며, 건조제 처리효과는 없었고, conditioning과 건조제의 병행처리는 conditioning 단독처리에 비해 효과적이지 못하였다. 또 양질의 건초 조제를 위해서는 늦어도 출수기 수확이 유리하였다.

• 한국잠사곤충학회지
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• 제40권1호
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• pp.8-12
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• 1998

The study aimed at development of a riding-type mulberry harvester for mechanical harvest. A riding-type mulberry harvester has been developed to harvest on sloped land with a higher efficiency. It has been implemented over a period of 2 years from 1996 to 1997. The result is as follows. It moves on carterpillar with a level adjusting system. It reduced only from 14.6 hrs to 0.9hrs/10a for cutting in a range of 25 to 80 cm high and possibly used for both spring and autumn. It reduced only the labor requirements of mulberry harvesting by 94 percent, as compared to that of the manual harvest. All related processes, cutting, binding and loading are simultaneously done by this harvester and totally it can reduce 96 percent of the labor requirements, as compared to 20.4 hrs/10a of the manual harvest. The machine compared to improved mulberry harvest efficiency with 11.11a per hour by about 23 times as compared to 0.49a per hour manpower. Cost analysis indicated that the riding-type mulberry harvester saved overall cost by 66 percent from 980,000 won per ha manpower to 330,000 won per ha.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.268-273
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• 2001

A fundamental study on the harvest-type ice storage system applied ice making method in-water and its temperature characteristics in ice storage system was performed experimentally of the charge and discharge of cold. This paper is concerned with the development of a new method for making and separating ice and saving floated ice by installing an evaporation plate at in-water within a storage tank. In a conventional harvest-type ice storage system, a tank saves ice by separating a formed ice from an installed evaporation plate, which is located above an ice storage tank as an ice storage system. A new harvest-type method shows very good heat transfer efficiency than a convectional method. It is because the evaporation panel is directly contacted with water in a storage tank. Also, at a conventional system a circulating pump, a circulating water distributor and a piping are installed, but these components are not necessary in a new method. In this study two kinds of ice storage systems are experimentally investigated to study the thermal characteristics of ice storage tanks.

• 대한기계학회논문집B
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• 제25권5호
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• pp.653-659
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• 2001

This paper is concerned with the development of a new method for making and separating ice in-water and saving floated ice by installing an evaporation panel in an ice storage tank. The new method shows very good heat transfer efficiency than that of the convectional method. It is because the evaporation panel is directly contacted with water in the storage tank. The experiments were performed by varying inlet and outlet refrigerant temperatures of its evaporator. From the experimental results, the operating characteristics of in-water harvest-type ice storage system were investigated by measuring temperature and pressure at each point of the ice storage system and power required to operating compressor respect to the changes of the inlet and outlet refrigerant temperature of evaporator. It can be think that defrost frequency decreased and heavy ice created as the refrigerant temperature of evaporator outlet and defrost setting temperature is low so gotten result can effect to release efficiency. Also, consumption power, condensing heat quantity, refrigerating capacity and performance efficiency decreased as time goes by. Therefore, these results provide the basic data for system optimization, performance improvement and the possibility of application to other fields.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.407-410
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• 2009

A piezoelectric device which converts mechanical vibration energy into electrical energy is able to harvest energy and the usable energy is mW ${\sim}$ W, hence a converter is necessary to acquire the energy efficiently. Various limited conditions should be considered for the design of AC/DC converter for energy harvesting of a piezoelectric device supplying small amount of energy. In addition to simple structure, compact size, light weight and high efficiency, the energy harvesting AC!DC converter should adopt the technique of self operating, in which only the harvested energy from the piezoelectric device is available. This paper proposes new AC/DC resonant boost converter to harvest efficiently electrical energy from mechanical vibration energy, analyzes the operating characteristics of the converter and proves its feasibility for energy harvester with PSPICE simulation and experiment.