• 생물환경조절학회지
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• 제23권4호
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• pp.269-280
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• 2014

To cope with increasing of vegetables and flowers consumptions, horticulture facilities have been modernized. Korea government recently announced construction plan of new greenhouse complex at reclaimed land. However wind characteristics of reclaimed land is totally different from those of inland, wind pressure on greenhouse built in reclaimed land should be carefully evaluated to secure structural safety on the greenhouse. In this study, as a first step, wind pressure coefficient and local wind pressure coefficient on even-span greenhouse were measured using wind tunnel test. ESDU was adopted to realize wind characteristics of reclaimed land such as wind and turbulence profiles. From the wind tunnel test, when wind direction was 0 degree, it was concluded that KBC2009 standard underestimated scale of wind pressure coefficients at roof area of greenhouse whereas NEN-EN2002 standard underestimated those at every surface of greenhouse. When wind direction was 90 degree, both standards did not well reflect the characteristics of wind pressure distribution. From the analysis of local wind pressure coefficients according to wind direction conditions, design of covering, glazing bar of greenhouse where large effects of the local wind pressure were estimated should be well established. Wind pressure coefficients and local wind pressure coefficients according to parts of the greenhouse were finally suggested and these results could be practically used for suggesting new design standards of greenhouse.

• 한국농공학회논문집
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• 제60권4호
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• pp.105-111
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• 2018

Institutional inertia anti-disaster standard was presented mainly on the upper surface, it is necessary to improve to the soil type standard and uplift the resistance standard greenhouse that are vulnerable to strong winds. In this study, we carried out a field test using the load control method in order to evaluate the uplift resistance of continuous foundation of greenhouse with different depths of the rafters. Institutional inertia anti-disaster standard of greenhouse foundation did not protect the greenhouse structure from the damages caused by strong winds and heavy snow. Therefore, field tests for behavior characteristics of continuous greenhouse foundation were carried out to ensure stable facility cultivation. The field test condition was evaluated using different embedded depth as follows: 30cm, 40cm, 50cm and spacing 50cm, 60cm, 70 cm. As a result of the uplift resistance field tests using the load control method, the minimum uplift resistance was found to be over 90kg and uplift resistance displacement was 9.4mm. Uplift resistance of the continuous greenhouse foundation was in the range of 90-180 kg according to embedded depth and spacing. Using the test condition, there was no constant trend in the uplift resistance.

• 한국농공학회논문집
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• 제63권6호
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• pp.17-26
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• 2021

Greenhouses have been damaged due to the uplift pressure from strong wind, for which rebar piles are often installed near the greenhouse to resist the pressure. For the effective design of rebar piles, it is necessary to access the shear strength of soil on which the greenhouse is constructed. This study experimentally evaluates the shear strength of the soil beneath the greenhouse. Four soil samples were collected from four agricultural sites, and prepared for testing with 75, 80, 85, and 90% compaction rates. One-dimensional unconfined compression test (UC), consolidated-undrained triaxial test (CU), and resonant column test (RC) were performed for the evaluation of shear strength and shear modulus. Generally, the higher shear strength and modulus were observed with the higher compaction rates. In particular, the UC shear strength increases with the increase of #200 sieve passing rate. Resulting from the CU test, the sample with the most of coarse soil had the highest friction angle, but the variation is small among samples. Resulting from the CU and RC tests, the ratio of maximum shear modulus with the major principle stress at failure was the higher at the finer soil. The ratio was two to three times greater than the ratio from the standard sand. This indicates that the shear strength is lower for the fine soil than the coarse soil at the same shear modulus. The results of this study will be a useful resource for the estimation of the pull-out strength of the rebar pile against the uplift pressure.

• 한국산업보건학회지
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• 제20권2호
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• pp.79-87
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• 2010

Objectives: The purpose of this study was to investigate the symptoms of work-related musculoskeletal disorders (WMSDs), the influence of the WMSDs on the health-related quality of life (HRQoL), and to identify the differences of WMSDs and HRQoL between greenhouse farmers and paddy farmers. Methods: Subjects were 34 greenhouse farmers and 56 paddy farmers who were living in a rural community. The sociodemographic characteristics, health-related behavior, working characteristics, WMSDs and HRQoL were investigated. WMSDs symptoms were measured by a selfassessed questionnaire on musculoskeletal disorders symptoms and HRQoL was measured by the Euro Quality of Life (Euroqol) EQ-5D index. The differences on the WMSDs, EQ-5D and it's related factors between the groups were assessed with t-test and ${\chi}^2$-test. Results: Greenhouse farmers were longer the working hours per day and working duration than paddy farmers. The level of prevalence of the WMSDs in greenhouse farmers is higher than in paddy farmers. The EQ-5D index of greenhouse farmers and paddy farmers were 0.819 and 0.874, respectively. Overall, the mean value of EQ-5D index was significantly lower greenhouse farmers than paddy farmers. Conclusions: These results showed that the HRQoL for farmers are strongly influenced by WMSDs and agicultural type in that we are aware of the need to comply with regulations of WMSDs, especially greenhouse farmers.

• 한국농공학회논문집
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• 제58권2호
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• pp.45-52
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• 2016

The object of this paper was to evaulate modified proposed design equation in model test result in order to estimate uplift-resistance of timber pile of reclaimed land greenhouse foundation. Uplift resistance result of model test was increased to according to increased of contact area. Uplift-resistance result of field test tend to lineary increased to according to increased of embedment depth and contact area. Results of field uplift-resistance was evaluate compare with modified proposed design equation results of model test and Effective stress method. As the Effective stress method tend to underestimate, modified proposed design equation results of model test tend to similar type. As the contact area increase, difference between field uplift-resistance results and modified proposed design equation results of model test was considered uplift-speed.

• 한국작물학회지
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• 제43권4호
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• pp.239-244
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• 1998

Susceptibility of soybean cultivars to Calonectria illicicola was evaluated in a greenhouse by inoculating seedlings with mycelium in agar discs placed on the stems at the soil line. A range of responses was detected among cultivars following inoculation with a virulent isolate of C.ilicicola. Rankings of cultivars between greenhouse tests 1 and 2 were similar for disease severity and areas under the disease progress curves (AUDPC). In addition, rankings of cultivars for Final disease severity were highly correlated with AUDPC in test 1 ($r_s$ =0.88, t =5.48, p<0.001), test 2 ($r_s$ =0.99, t =22.10, p<0.001), and when tests were combined ($r_s$=0.89, t=5.82, p<0. 001). Final disease severity and AUDPC consistently identified Asgrow 7986, Braxton, Cajun, and Forrest as soybean cultivars least susceptible to red crown rot. In 1993 and 1994 field tests, a range in disease susceptibility was observed for tested cultivars but none was completely resistant. Soybean cultivars Braxton, Cajun, and Forrest, which were least susceptible to red crown rot in greenhouse tests, also ranked among cultivars with the lowest disease incidence and AUDPC in field tests. Comparisons .between rankings of the eight cultivars common to greenhouse and field tests showed a correlation between final disease severity from combined greenhouse tests and both final disease incidence ($r_s$=0.63, t =1.99, p<0.1) and AUDPC ($r_s$=0.60, t =1.82, p < 0.2) from the combined field tests. However, AUDPC from greenhouse tests did not correlate with either final disease incidence or AUDPC from field tests. The green-house screening method provided consistent results between greenhouse and field tests and successfully identified the least susceptible cultivars Braxton, Cajun, and Forrest.

• 한국과학교육학회지
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• 제24권3호
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• pp.668-674
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• 2004

본 연구에서는 PISA 검사결과를 토대로 온실효과에 대하여 우리나라의 만 15세 학생들이 지니고 있는 전형적인 학생개념의 유형을 분석하였다. 온실효과에 대한 기존 선행연구에서 밝혀진 학생들의 대안적인 개념에 비추어 볼 때, 현재 우리나라의 만15세 학생들의 온실효과에 대한 이해 수준을 온실효과의 자연적 요인과 인위적 요인으로 나누어 분석하고, 온실 효과를 초래한 원인에 대한 학생들의 오개념 유형을 살펴보았다. 이산화탄소 이외에 지구의 온도 상승에 기여하는 요인들 우리나라 학생들은 프레온 가스, 매연, 수증기, 메탄 등을 지적하였다. 또한 많은 학생들이 온실효과와 오존층 파괴가 인과관계를 지니고 있는 것으로 파악하고 있음을 알 수 있었다. 과학과 교수 학습에 얻을 수 있는 시사점을 도출하였다.

• 한국환경과학회지
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• 제30권11호
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• pp.907-914
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• 2021

In this study, strawberry cultivation environment in a greenhouse located in Jeonju was monitored and internal environmental parameters were analyzed. Temperature, humidity, RAD, and PPF sensors were installed to monitor environmental conditions in the test greenhouse. Data were collected every 10 minutes during four winter months from sensors placed across the greenhouse to assess its permeability and environmental uniformity. Temperature and humidity inside the greenhouse were relatively uniform with negligible deviations among the center, south, and north; however, it was judged that further analysis of gradients of these parameters from the east to the west of the greenhouse would be needed. Both RAD (Total solar radiation) and PPF (Photosynthetic photon flux) had high values on the south and were low on the north and the reduction rate of these parameters was 54% and 61%, respectively, indicating that a significant amount of light could not be transmitted. This implied a significant decrease in the amount of light entering the greenhouse during winter. Therefore, it is concluded that environmental control devices and auxiliary lighting are needed to achieve uniform greenhouse environment for efficient strawberry cultivation.

• Journal of Microbiology and Biotechnology
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• 제24권1호
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• pp.1-7
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• 2014

The possibility of using hyphomycete fungi as suitable biocontrol agents against greenhouse whitefly has led to the isolation of various insect pathogenic fungi. Among them is Beauveria bassiana, one of the most studied entomopathogenic fungi. The objective of this study was to use B. bassiana M130 as an insecticidal agent against the greenhouse whitefly. M130 isolated from infected insects is known to be a biocontrol agent against greenhouse whitefly. Phylogenetic classification of M130 was determined according to its morphological features and 18S rRNA sequence analysis. M130 was identified as B. bassiana M130 and showed chitinase (342.28 units/ml) and protease (461.70 units/ml) activities, which were involved in the invasion of the host through the outer cuticle layer, thus killing them. The insecticidal activity was 55.2% in petri-dish test, 84.6% in pot test, and 45.3% in field test. The results of this study indicate that B. bassiana has potential as a biological agent for the control of greenhouse whitefly to replace chemical pesticides.

• 한국환경과학회지
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• 제25권1호
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• pp.23-29
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• 2016

This study has conducted greenhouse gas emission reduction test as using Oyster-shells originated PCC paper filler compare to non-Oyster shells used PCC. This examination was estimated and calculated in accordance with both IPCC (Intergovernmental Panel on Climate Change) and World Business Council for Sustainable Development (WBSCD). The greenhouse gas emission reduction estimation result indicates that, when oyster shells are recycled and used as paper filler, it reduces $27.97tCO_2\;per\;100\;ton$ of oyster shells. It is greenhouse gas emission $44.27tCO_2$ from PCC production changed to carbon emission reduction when replaced with oyster shell. LNG greenhouse gas emission $16.3tCO_2$ in relation to the pre-treatment with oyster shell per 100 ton is also reflected. As a result, it is assumed that roughly $0.2797tCO_2/oyster\;shell{\cdot}ton$.