• Tunnel and Underground Space
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• v.10 no.3
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• pp.410-417
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• 2000

The distinct element method has been effectively applied to the analysis of stability and behavior of jointed rock masses. In this paper the modelling characteristics of different types of distinct element model were investigated. Arch tunnel examples were chosen to compare the calculation results of two computer codes, NURBM and CBLOCK, where the former is based on implicit algorithm, and the other on explicit one. CBLOCK calculations show that joint properties are very important parameters in the stability analysis and that the joint stiffness ratio associated with joint configuration could be used as an indicator, whereas NURBM differ from that. Some other disagreements were also identified.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.73-85
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• 2009

An investigation was conducted to get the basic data for establishing structural safety and environmental management of tomato greenhouses in Chungnam region. The contents of the investigation consisted of actual state of greenhouse structures and environmental control facilities. Most of greenhouses were arch type single-span plastic houses and they had too low height for growing tomatoes. Frameworks of multi-span greenhouses were suitable, but those of single-span were mostly insufficient. Every greenhouse had thermal curtain movable or covering fixed inside the greenhouse for energy saving, and heating facilities were mostly warm air heater. Irrigation facilities were mostly drip tube and controlled by manual operation or timer. Almost all of the greenhouses didn't install high level of environmental control facilities such as ventilator, air circulation fan, $CO_2$ fertilizer, insect screen, supplemental light, and cooling device.