• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.1
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• pp.1-7
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• 2010

Rural facilities need to be changed to be industrialized and long span structures due to accelerating aging of the rural population. In this study, the optimized structure was developed by applying Pre-Engineered Building System using the tapered member to make that the Korea standard green house has a long span. When considering design load, reasonable values were adapted by reviewing existing design codes. As a result, applying pre-engineered building system was efficient in structural system that has span longer than 16 m. And it was concluded that the increase with the longitudinal span from 4 m to 12 m was more efficient in aspect of steel amount.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.4
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• pp.14-21
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• 2015

Korean government plans to establish large-scale horticulture facility complexes using reclaimed land in order to improve the national competitiveness of agriculture at the government level. One of the most significant problems arising from the establishment of those large-scale horticulture facilities is that these facilities still largely depend on a fossil fuel and they require 24 h a day heating during the winter season in order to provide the necessary breeding conditions for greenhouse crops. These facilities show large energy consumption due to the use of coverings with large heat transmission coefficients such as vinyl and glass during heating in the winter season. This study investigated the applicability of waste heat from power plant for large-scale horticulture facilities by evaluating the waste heat water temperature, heat loss and energy saving performance as a function of distance between power plant and greenhouse. As a result, utilizing power plant waste heat can reduce the energy consumption by around 85% compared to the conventional gas boiler, regardless of the distance between power plant and greenhouse.

• Journal of Animal Science and Technology
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• v.60 no.11
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• pp.27.1-27.8
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• 2018

Background: Enteric methane ($CH_4$) accounts for about 70% of total $CH_4$ emissions from the ruminant animals. Researchers are exploring ways to mitigate enteric $CH_4$ emissions from ruminants. Recently, nano zinc oxide (nZnO) has shown potential in reducing $CH_4$ and hydrogen sulfide ($H_2S$) production from the liquid manure under anaerobic storage conditions. Four different levels of nZnO and two types of feed were mixed with rumen fluid to investigate the efficacy of nZnO in mitigating gaseous production. Methods: All experiments with four replicates were conducted in batches in 250 mL glass bottles paired with the ANKOM$^{RF}$ wireless gas production monitoring system. Gas production was monitored continuously for 72 h at a constant temperature of $39{\pm}1^{\circ}C$ in a water bath. Headspace gas samples were collected using gas-tight syringes from the Tedlar bags connected to the glass bottles and analyzed for greenhouse gases ($CH_4$ and carbon dioxide-$CO_2$) and $H_2S$ concentrations. $CH_4$ and $CO_2$ gas concentrations were analyzed using an SRI-8610 Gas Chromatograph and $H_2S$ concentrations were measured using a Jerome 631X meter. At the same time, substrate (i.e. mixed rumen fluid+ NP treatment+ feed composite) samples were collected from the glass bottles at the beginning and at the end of an experiment for bacterial counts, and volatile fatty acids (VFAs) analysis. Results: Compared to the control treatment the $H_2S$ and GHGs concentration reduction after 72 h of the tested nZnO levels varied between 4.89 to 53.65%. Additionally, 0.47 to 22.21% microbial population reduction was observed from the applied nZnO treatments. Application of nZnO at a rate of $1000{\mu}g\;g^{-1}$ have exhibited the highest amount of concentration reductions for all three gases and microbial population. Conclusion: Results suggest that both 500 and $1000{\mu}g\;g^{-1}$ nZnO application levels have the potential to reduce GHG and $H_2S$ concentrations.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.215-235
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• 1996

The thermal analysis by mathematical model simulation makes it possible to reasonably predict heating and/or cooling requirements of certain greenhouses located under various geographical and climatic environment. It is another advantages of model simulation technique to be able to make it possible to select appropriate heating system, to set up energy utilization strategy, to schedule seasonal crop pattern, as well as to determine new greenhouse ranges. In this study, the control pattern for greenhouse microclimate is categorized as cooling and heating. Dynamic model was adopted to simulate heating requirements and/or energy conservation effectiveness such as energy saving by night-time thermal curtain, estimation of Heating Degree-Hours(HDH), long time prediction of greenhouse thermal behavior, etc. On the other hand, the cooling effects of ventilation, shading, and pad ||||&|||| fan system were partly analyzed by static model. By the experimental work with small size model greenhouse of 1.2m$\times$2.4m, it was found that cooling the greenhouse by spraying cold water directly on greenhouse cover surface or by recirculating cold water through heat exchangers would be effective in greenhouse summer cooling. The mathematical model developed for greenhouse model simulation is highly applicable because it can reflects various climatic factors like temperature, humidity, beam and diffuse solar radiation, wind velocity, etc. This model was closely verified by various weather data obtained through long period greenhouse experiment. Most of the materials relating with greenhouse heating or cooling components were obtained from model greenhouse simulated mathematically by using typical year(1987) data of Jinju Gyeongnam. But some of the materials relating with greenhouse cooling was obtained by performing model experiments which include analyzing cooling effect of water sprayed directly on greenhouse roof surface. The results are summarized as follows : 1. The heating requirements of model greenhouse were highly related with the minimum temperature set for given greenhouse. The setting temperature at night-time is much more influential on heating energy requirement than that at day-time. Therefore It is highly recommended that night- time setting temperature should be carefully determined and controlled. 2. The HDH data obtained by conventional method were estimated on the basis of considerably long term average weather temperature together with the standard base temperature(usually 18.3$^{\circ}C$). This kind of data can merely be used as a relative comparison criteria about heating load, but is not applicable in the calculation of greenhouse heating requirements because of the limited consideration of climatic factors and inappropriate base temperature. By comparing the HDM data with the results of simulation, it is found that the heating system design by HDH data will probably overshoot the actual heating requirement. 3. The energy saving effect of night-time thermal curtain as well as estimated heating requirement is found to be sensitively related with weather condition: Thermal curtain adopted for simulation showed high effectiveness in energy saving which amounts to more than 50% of annual heating requirement. 4. The ventilation performances doting warm seasons are mainly influenced by air exchange rate even though there are some variations depending on greenhouse structural difference, weather and cropping conditions. For air exchanges above 1 volume per minute, the reduction rate of temperature rise on both types of considered greenhouse becomes modest with the additional increase of ventilation capacity. Therefore the desirable ventilation capacity is assumed to be 1 air change per minute, which is the recommended ventilation rate in common greenhouse. 5. In glass covered greenhouse with full production, under clear weather of 50% RH, and continuous 1 air change per minute, the temperature drop in 50% shaded greenhouse and pad ＆ fan systemed greenhouse is 2.6$^{\circ}C$ and.6.1$^{\circ}C$ respectively. The temperature in control greenhouse under continuous air change at this time was 36.6$^{\circ}C$ which was 5.3$^{\circ}C$ above ambient temperature. As a result the greenhouse temperature can be maintained 3$^{\circ}C$ below ambient temperature. But when RH is 80%, it was impossible to drop greenhouse temperature below ambient temperature because possible temperature reduction by pad ||||&|||| fan system at this time is not more than 2.4$^{\circ}C$. 6. During 3 months of hot summer season if the greenhouse is assumed to be cooled only when greenhouse temperature rise above 27$^{\circ}C$, the relationship between RH of ambient air and greenhouse temperature drop($\Delta$T) was formulated as follows : $\Delta$T= -0.077RH＋7.7 7. Time dependent cooling effects performed by operation of each or combination of ventilation, 50% shading, pad ＆ fan of 80% efficiency, were continuously predicted for one typical summer day long. When the greenhouse was cooled only by 1 air change per minute, greenhouse air temperature was 5$^{\circ}C$ above outdoor temperature. Either method alone can not drop greenhouse air temperature below outdoor temperature even under the fully cropped situations. But when both systems were operated together, greenhouse air temperature can be controlled to about 2.0-2.3$^{\circ}C$ below ambient temperature. 8. When the cool water of 6.5-8.5$^{\circ}C$ was sprayed on greenhouse roof surface with the water flow rate of 1.3 liter/min per unit greenhouse floor area, greenhouse air temperature could be dropped down to 16.5-18.$0^{\circ}C$, whlch is about 1$0^{\circ}C$ below the ambient temperature of 26.5-28.$0^{\circ}C$ at that time. The most important thing in cooling greenhouse air effectively with water spray may be obtaining plenty of cool water source like ground water itself or cold water produced by heat-pump. Future work is focused on not only analyzing the feasibility of heat pump operation but also finding the relationships between greenhouse air temperature(T$_{g}$ ), spraying water temperature(T$_{w}$ ), water flow rate(Q), and ambient temperature(T$_{o}$).

• Solar Energy
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• v.18 no.3
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• pp.51-61
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• 1998

This study attempts to suggest the architectural design methods of toplight system, which is a glass covered space on the top of building with greenhouse for instance. In this study, toplight system will be experimented, analysed and presented as a solution method for environmental control system in the summer.

• Membrane Journal
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• v.21 no.1
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• pp.55-61
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• 2011

$BaCo_{0.7}Fe_{0.22}Nb_{0.08}O_{3-{\delta}}$ oxide was synthesized by solid state reaction method. Dense ceramic membrane was prepared using as-prepared powder by pressing and sintering at $1,200^{\circ}C$. XRD result of membrane showed single perovskite structure. Leakage and oxygen permeation test were conducted on the membrane sealed by glass ring as a sealing material. The oxygen permeation flux increased with increasing temperature and pressure difference and maximum oxygen permeation flux was $2.3mL/min{\cdot}cm^2$ at $950^{\circ}C$ with $Po_2$ = 0.63 atm of oxygen partial pressure. The oxygen permeation in the condition of air with $CO_2$ (300 ppm) as feed stream decreased as much as only maximum 2.9% in comparison with air feed stream. It indicated $BaCo_{0.7}Fe_{0.22}Nb_{0.08}O_{3-{\delta}}$ membrane is more stable than another membrane for carbon dioxide.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.242-249
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• 1997

Environmental control operations have been considerably contributed to the reduction of labor cost in both plastic film and glass greenhouses since government supported projects were begun. However, some problems are still remaining on the optimal environmental control and excessive operation due to an inflexible software regulating ventilation gear - reducers. The unadjustable software caused the damage of ventilation system, resulting in heat stresses of crops. This study was performed to develop a ventilation software controlling the vent opening level, opening sequence, based on the wind direction, and control interval according to the difference between ambient and set- up temperatures. The software included a beeper system alarming urgent cases, while a manager was remote from the greenhouse. A compatible hardware with the software was also developed by using a low-cost diffused DSP controller.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.247-257
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• 2014

Assessment for operator's dermal and inhalation exposure to acetamiprid during cultivation of water melon in greenhouse was carried out. For dermal exposure measurement, whole body dosimetry (WBD) was performed as the first trial in Korea. WBD consists of cotton/polyester outer clothes and cotton inner clothes. Hand exposure was measured by washing of nitrile gloves and hands while head exposure was monitored by face/neck wipe technique. Inhalation exposure was monitored with personal air sampling pumps and IOM sampler (glass fiber filter). Analytical limit of quantitation was 2.5 ng/mL. Good reproducibility (C.V < 8.7%), linearity ($R^2$ > 0.99) and recovery (70~119%) were obtained. Field recovery of acetamiprid was 77~95%. During mixing/loading, hand exposure of acetamiprid was about 10 times ($229.7{\mu}g$) more than that of application case ($20.9{\mu}g$). During application, total dermal exposure was $1207.4{\mu}g$. Exposure of lower legs was $1132.1{\mu}g$, which is 93.8% of the total dermal exposure. Inhalation exposure during mixing/loading and application was not detected. Margin of safety (MOS) was calculated for risk assessment using male Korean average body weight (70 kg) and acceptable operator exposure level ($124{\mu}g/kg/day$) to give 140, suggesting that health risk of operator during treatment of acetamiprid for water melon in greenhouse could be safe.

• Journal of Korean Society of Rural Planning
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• v.24 no.4
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• pp.57-67
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• 2018

We examined the impact of paddy wetland's avian-diversity on the development of the protected horticulture complex. The results of this study were made to propose ecological protected horticulture complex and development direction suitable for avian habitat. The total number of species surveyed was analyzed as 1168 individuals in 11 orders 26 families and 36 generic 48 species. Type average was analyzed as paddy $17.25{\pm}4.83$ species and $74.50{\pm}38.08$ individuals, glass $10.00{\pm}0.82$ species and $46.75{\pm}2.06$ individuals, single $13.75{\pm}7.27$ species and $59.50{\pm}35.34$ individuals, multi $8.75{\pm}0.96$ species and $36.75{\pm}9.29$ individuals. Paddy showed higher species diversity than protected horticulture complex. The average number of species surveyed for one year was glass $14{\pm}2.83$, multi $12{\pm}1.41$, single $18{\pm}11.31$, and paddy $26{\pm}11.31$. The diversity difference was identified as paddy> single> glass and multi. Statistical analysis showed statistical difference of Ciconiiformes. Development of protected horticulture complex causes loss of avian habitat. The diversity index was glass $1.73{\pm}0.07$, multi $1.68{\pm}0.14$, single $1.91{\pm}0.47$, and paddy $2.29{\pm}0.17$. Paddy has a higher species diversity than the protected horticulture complex. For the purpose of ecological protected horticulture complex, detention ponds, artificial wetlands and habitats should be reflected in the design. This should be applied to reclamation areas or large-scale protected horticulture complexes.

• Computers and Concrete
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• v.19 no.4
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• pp.419-427
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• 2017

With the rising global environmental awareness on energy saving and carbon reduction, as well as the environmental transition and natural disasters resulted from the greenhouse effect, waste resources should be efficiently used to save environmental space and achieve environmental protection principle of "sustainable development and recycling". This study used recycled cement mortar and adopted the volumetric method for experimental design, which replaced cement (0%, 10%, 20%, 30%) with recycled materials (fly ash, slag, glass powder) to test compressive strength and ultrasonic pulse velocity (UPV). The hyperbolic function for nonlinear multivariate regression analysis was used to build prediction models, in order to study the effect of different recycled material addition levels (the function of $R_m$(F, S, G) was used and be a representative of the content of recycled materials, such as fly ash, slag and glass) on the compressive strength and UPV of cement mortar. The calculated results are in accordance with laboratory-measured data, which are the mortar compressive strength and UPV of various mix proportions. From the comparison between the prediction analysis values and test results, the coefficient of determination $R^2$ and MAPE (mean absolute percentage error) value of compressive strength are 0.970-0.988 and 5.57-8.84%, respectively. Furthermore, the $R^2$ and MAPE values for UPV are 0.960-0.987 and 1.52-1.74%, respectively. All of the $R^2$ and MAPE values are closely to 1.0 and less than 10%, respectively. Thus, the prediction models established in this study have excellent predictive ability of compressive strength and UPV for recycled materials applied in cement mortar.