• 연구논문집
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• 통권32호
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• pp.35-43
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• 2002

This study was performed to develop accelerated life test method of machanical parts using cumulative damage theory that used to model the fatigue of parts that receive variable load. The cumulative damage theory was introduced, and the estimation of life and calculation of accelerated life test time was illustrated. As the actual application example, accelerated life test method of agricultural tractor transmission was described. Life distribution of agricultural tractor transmission was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 3,000 hours and 90% reliability for one test sample. According to the cumulative damage theory, because test time can shorten in case increase test load, test time could be reduced by 482 hours when we put the load 1.1 times of rated load than 0.73 times of rated load that is equivalent load calculated by load spectrum of the agricultural tractor. This time, acceleration coefficient was 11.7. This accelerated test method was used to develop accelerated test method of gear reducer, hydraulic hose and bearing as well as agricultural tractor transmission and it is considered to be applied comprehensively to machanical parts the fatigue of which is happened by load or pressure etc.

• 한국응용곤충학회지
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• 제48권4호
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• pp.485-491
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• 2009

단감에 피해를 일으키는 노린재의 피해양상을 밝히기 위해 접종시기별, 접종밀도별 피해과율을 조사하였다. 톱다리개미허리노린재에 의한 피해과율은 접종밀도, 접종시기, 먹이조건에 따라 유의하게 차이가 있었으며 결과모지당 5마리 접종구에서부터 피해를 보이며 접종시기에서는 6월, 7월, 8월에는 피해가 적었으며 9월, 10월에 피해과가 많아졌다. 단감을 단일먹이로 한 것과 강낭콩과물을 제공한 먹이조건에서의 피해과율에서 유의하게 차이가 있었다. 톱다리개미허리노린재에 의한 피해과는 흡즙흔적이 있는 식흔과로 남으며 흡즙에 의한 낙과증상은 없었다. 썩덩나무노린재는 7월, 8월, 9월의 접종시기별 피해과율이 유의하게 차이가 있었으며 접종밀도에 따른 피해과율에 유의하게 차이가 있어 5마리 처리구에서는 7월의 경우 100%의 피해과율을 보였다. 갈색날개노린재의 접종시기에 따른 피해과율은 유의한 차이가 없었고 접종수준에 따른 피해과율은 1마리, 3마리, 5마리에서 각각 유의하게 차이가 있었다. 피해증상으로 톱다리개미허리노린재와 달리 7월, 8월에는 피해를 받은 과일이 대부분 낙과되었으나 9월 이후의 피해과는 낙과되지 않고 식흔과가 많았다.

• 한국환경농학회지
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• 제34권4호
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• pp.350-354
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• 2015

BACKGROUND: Botanical insecticides, especially Azadirachta Indica extract (AIE) and Sophorae radix extract (SRE) are widely used in Agriculture field. In our previous studies on genotoxicity test of AIE and SRE samples, a suspicious clastogenic properties was shown. Herein, we investigated the DNA damage effect of these botanical insecticide samples through the in vitro comet assay. METHODS AND RESULTS: Chinese hamster lung (CHL) fibroblast cell line was used, and methyl methanesulphonate was as positive control. Respective two samples of AIE and SRE were evaluated using Single Cell Gel Electrophoresis (Comet) assay and measured as the Olive tail moment (OTM). Results from this study indicated that all tested AIE and SRE samples did not show DNA damage in comet assay using CHL cells, compared with control. CONCLUSION: AIE and SRE samples used in this study were not cause genetic toxicity and are suitable for use as organic materials.

• 한국농림기상학회지
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• 제17권3호
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• pp.270-274
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• 2015

산간지역의 계곡 물길의 매립과 지하배수관의 설치에 따른 인근 논에서 벼 냉수해에 대한 민원이 제기되어 벼 냉수해와 지하배수관 설치의 연관성 유무을 파악하기 위해서 현장조사 및 분석을 실시하였다. 결론적으로 지하배수관 설치로 인하여 계곡물의 온도가 지하배수관 설치 전보다 $0.5{\sim}4.5^{\circ}C$ 범위로 낮아진 것으로 분석되었고, 이 냉수를 농업용수로 관개한 하류쪽 논에서는 벼 냉수해가 발생할 가능성이 매우 높았을 것으로 판단되었다. 따라서, 적절한 수온상승 조치를 취하지 않으면 냉수해로 인하여 정상적인 수확이 불가능할 것으로 평가되었다.

• Journal of Biosystems Engineering
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• 제34권5호
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• pp.325-330
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• 2009

This study was performed to develop accelerated life test methods for agricultural tractor transmission receiving variable load. To acquire parameters for calculation of accelerated life test, endurance tests were performed under different torque conditions. Test results showed that the shape factor of Weibull distribution was 1.5 and fatigue damage exponent was 5.4. The calculated test time was 5,877 hours under the conditions of average life (MTBF) 3,000 hours and 90% reliability for one test sample. According to the linear cumulative damage rule, test time could be reduced using increased test load. Test time could be reduced by 252 hours when 1.2 times of the rated load compared with 0.67 times of the rated equivalent load calculated by load spectrum of the agricultural tractor. Calculated acceleration coefficient was 23.3.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.291-296
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• 1993

Taking a bledes axle of rotary tiller as a example, this paper discusses influences of four loading essential factors, which are strengthened amplitude, cycle times, loading sequence and loading frequency. in fatigue life. Determination principles of above four factors and monitoring methods of fatigue damage by local strain are dealt with. The actual field testing check of farm machinery is rapidly simulated by laboratory program fatigue test can shorten the period of development and improvement of a product. In the time of in-door simulation test, damage monitoring and four loading essential factors, which are strengthened amplitude , cycle times, loading sequence and loading frequency, have to be dealt with . If these problems are solved successfully, it is possible to accelerated test speed, reduce costs and manhours, and raise accuracy of test result. However strengthening method, loading pattern and influence of loading frequency on test result have not so far been discu sed systematically, damage monitoring is even more a difficult problem. Authors have studied above problems with the object of blades axle of rotary tiller.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.205-210
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• 1993

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.202-206
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• 2001

In this study, the risk assessment of small reservoir by collapse using GIS is evaluated. Direct damage distance from collapsed reservoir is estimated by empirical USBR equations and submerged area is calculated by USBR's idea. The amount of damage by collapsed reservoir is figured out by damage assessment of National Institute for Disaster Prevention.

• 한국습지학회지
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• 제11권2호
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• pp.77-87
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• 2009

가뭄은 다른 재해와 다른 특징을 지니고 있는데 이는 가뭄기간에 따라 그 파급효과가 오랫동안 지속될 수 있다는 것이며 이로 인해, 가뭄피해액을 산정하기도 쉽지 않다는 점이다. 이에 본 연구에서는 가뭄에 의한 피해를 파악하기 위하여 가뭄피해자료가 구축되어 있는 농업부문과 생활용수부분에 대한 가뭄피해액을 산정하고자 하였다. 우선 국내외의 가뭄피해액을 산정하기 위한 방법들을 검토하였고 이를 토대로 국내에 적용가능한 방안을 제시하고 적용하였다. 2006~2008년의 가뭄에 대하여 경상남도 김해시, 남해군, 의령군, 창녕군, 창원시의 피해액을 추정하였다. 그 결과 농업부문에 있어서 정곡은 2006년에 의령군에서 약 1억9천5백만원, 미곡은 창녕군에서 약 6천7백만원으로 가장 높은 피해액이 추정되었다. 생활용수 부문에서는 2007년을 기준으로 고통비용을 40만원으로 가정하여 피해액을 추정하였으며, 남해군의 4개의 읍.면의 피해지역에서 약 214억 6천만원으로 추정되어 가장 큰 피해가 추정되었다. 가뭄으로 인한 피해 추정을 개선하기 위해서 농업부문의 경우는 현재의 자료를 최대한 활용하는 방향으로 추정방법을 개발하고, 생활용수부문의 경우는 고통비용의 산정과 용수 사용에 대한 가중치를 고려한다면 보다 현실성 있는 피해액 산정방법을 제시할 수 있을 것이다.

• 한국작물학회지
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• 제48권2호
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• pp.108-112
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• 2003

Foehn damage on rice plant is one of the important abiotic stresses in eastern costal area of Korea. To know the relationship between foehn impact and morphological traits of rice, wind tunnel method was used with 106 rice cultivars. Less influencing traits on foehn were short panicle, large panicle number per hill, thin panicle neck, and the flag leaf of narrow, short and thick. Leaf pubescence reduced the impact on foehn. 'Naepungbyeo' belong-ed to foehn tolerant varietal group, while 'Ansanbyeo' belonged to the opposite group. Three levels of root cutting treatment with two rice cultivars were conducted to evaluate the foehn impact using wind tunnel. The severity of wind damages was followed the sigmoidal curve duration of wind tunnel treatment were prolonged. Different responses of root cutting to wind tunnel treatment could be used to evaluate the severity of the foehn impact. 'Naepungbyeo' was one of the less implausible cultivars on foehn. 'Nae-pungbyeo' showed tolerant response to wind under 21% root removing treat-ment (20㎝ root cutting), however 'Ansanbyeo' was wilted under the same treatment. In case of 35 % root removing treatment(10㎝ root cutting), both rice cultivars failed to alive against foehn wind.