• International Journal of Aeronautical and Space Sciences
• /
• v.7 no.2
• /
• pp.50-55
• /
• 2006

Currently, a gas fueled diffusion flame is used for the relay torch system. It could be burned cleanly but should be stable at severe weather condition such as rain of up to 55 mm/h, winds of up to 70 km/h and also produce a highly bright yellow visible flame. This paper presents torch diffusion flame characteristics on the various wind speeds and rainfall conditions. From the results, flame lengths are controlled by the momentum flux ratio of fuel and ambient air flow and flame stability is much influenced by the mixing characteristics with air flow. Flame is fluctuated above than 200 mm/h rainfall and blow out is occurred about 300 mm/h rainfall condition.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.875-883
• /
• 2008

The amount of granite distribution area occupies about 40 - 50% of Korean Peninsula. The granite irregularly Intruded through preCambrian to Tertiary times but in Jurassic time so called, Daebo granite most widely crops out in Korean Peninsula. In addition to Bulkuksa Grante which intruded at Cretaceous time crops out at the southern part of Korean Peninsula and in northern part Triassic Songrim Granite is distributed. These granites have equigranular texture and are relatively isotropic. Their uniaxial compressive strength is above $1,500kg/cm^2$ and also seismic velocity is over 2,000m/sec. When these rocks receive a weathering action, the feldspar weathers first and the quartz grains remain plentifully to make the "Masato(Korean name)". Also when the granite receives a weathering action, quite often it make sheeting joint which is topographically parallel to the earth surface and also make a (so called, onion structure. These weathering phenomena easily make a land sliding when it is heavy rain and weathering surface is irregular.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.715-719
• /
• 2000

It is reported that we are facing the serious environment pollution difficulties such as acid rain, green house effects, etc. The gaseous matter CO, NOx, SOx, VOCs which are regarded as main factors for these current pollutions are mainly emitted from power plants and vehicles. Therefore several leading countries are regulating the related laws strictly, especially exhaust emissions from a Diesel engine without an after treatment device. The Objective of this study is to find out NOx removal characteristics focused on emissions of a Diesel engine using radical at each engine speed and load. It is generated from outer air and put into a mixing chamber in the end of exhaust line. In addition, the optimum temperature condition to activate reaction by radical is experimentally carried out. Concentration of exhaust emissions is analyzed from the gas anlayzer(KaneMay) and FTIR to estimate by-products.

• Journal of Industrial Technology
• /
• v.30 no.B
• /
• pp.99-108
• /
• 2010

This study was intended to estimate the soil runoff at the basin of Mandaechun where the measure needs to be taken to deal with the increasing muddy water resulting from soil runoff during wet season and torrential rain at the high reaches of the Soyang lake where highland vegetables are cultivated and soil replacement for improvement is carried out every two to three years. The study was carried out in such a way of identifying the topographic factors using geographical spatial data from Water Management Information System (WAMIS) and ARC-VIEW program and estimating the soil runoff by rainfall frequency using Revised Universal Soil Loss Equation (RUSLE), and furthermore, evaluating the soil runoff contribution at the basin of Mandaechun based on estimate of the soil runoff by section.

• Journal of Industrial Technology
• /
• v.26 no.B
• /
• pp.53-61
• /
• 2006

In this research, we have selected the regions of Naerin river and Inbuk river where agricultural activities are actively carried out in the upper Soyang Reservoir and we have observed the changes of water quality while raining after finding out the characteristics of the outflow of floating materials by measuring the water quantity and water quality in division of rainy season and non-rainy season for those floating materials of generating pollutions of turbidity and malnutrition of the water for 4 year from 2002 to 2005. Results of the observation showed that the outflow of floating materials is significantly affected by the surface outflow of rain water, in particular, the surface outflow was great in June -August period of flood seasons.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.188-193
• /
• 2011

This study was intended to estimate the soil runoff at the basin of Mandaechun where the measure needs to be taken to deal with the increasing muddy water resulting from soil runoff during wet season and torrential rain at the high reaches of the Soyang lake where highland vegetables are cultivated and soil replacement for improvement is carried out every two to three years. The study was carried out in such a way of identifying the topographic factors using geographical spatial data from Water Management Information System (WAMIS) and ARC-VIEW program and estimating the soil runoff by rainfall frequency using Revised Universal Soil Loss Equation (RUSLE), and furthermore, evaluating the soil runoff contribution at the basin of Mandaechun based on estimate of the soil runoff by section.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.3
• /
• pp.94-100
• /
• 2008

New type of the sewer drainage has been developed to overcome present sewer drainage's shortcoming. This system has the function of drainage, sewerage, reverse flow prevention, and harmful insect and smell prevention. Numerical simulation has been carried out in order to minimize the troubles that can be happened in the process of manufacture and installation process. This sewer drainage system for harmful insect and smell prevention intercepts pollution source, and then it prohibit second pollution. Harmful insect cannot go in and out in this system. Also, this system can reduce the damage of flooded districts due to heavy rain because it is impossible to flow backward from sewer drainage.

• Korean Journal of Environmental Agriculture
• /
• v.13 no.1
• /
• pp.31-38
• /
• 1994

This study was carried out to investigate the possibility of potential injury to crops which were exposed to precipitation. The rainwater were collected from May to September in 1992 and analyzed its chemical composition. The amounts of chlorophyll and cations in plant were measured, and the morphological structure of epidermis was also investigated by SEM. The results are summarized as follows: 1. The pH of precipitation in Suwon was relatively high even with high level of $SO_4^{2-}$ and monthly pH at May, June, July, August, and September were 4.65, 5.47, 5.32, 5.44 and 4.80, respectively. 2. The amount of ions in rainwater was in the order of $NH_4^+$, $Ca^{2+}$, $Mg^{2+}$ and $H^+$ for cations, and $SO_4^{2-}$, $NO_3^-$ and $Cl^-$ for anions. 3. pH of rain in less than 5mm of precipitation was higher than that in greater than 5mm of precipitation. 4. The amount of chlorophyll was higher in the plant exposed to rain than that in plant intercepted rain during the early portion of growing season, but at the later period, the trend was shown to be reversed. 5. When the sesame plants were exposed to rain at harvesting stage, they contained less amount of CaO, MgO and $Na_2O$ than those with the interception of rain. 6. Scanning electron microphotographs revealed the shringkage in glandular trichomes in the epidermis of sesame leaves when they were exposed to rain.

• Wind and Structures
• /
• v.36 no.2
• /
• pp.75-90
• /
• 2023

Turbulent wind flow over hilly terrains has been extensively investigated in the scientific literature and main findings have been included in technical standards. In particular, turbulent wind flow over nominally two-dimensional hills is often adopted as a benchmark to investigate wind turbine siting, estimate wind loading, and dispersion of particles transported by the wind, such as atmospheric pollutants, wind-driven rain, windblown snow. Windblown sand transport affects human-built structures and natural ecosystems in sandy desert and coastal regions, such as transport infrastructures and coastal sand dunes. Windblown sand transport taking place around any kind of obstacle is rarely in equilibrium conditions. As a result, the modelling of windblown sand transport over complex orographies is fundamental, even if seldomly investigated. In this study, the authors present a wind-sand tunnel test campaign carried out on a nominally two-dimensional sinusoidal hill. A first test is carried out on a flat sand fetch without any obstacle to assess sand transport in open field conditions. Then, a second test is carried out on the hill model to assess the sand flux overcoming the hill and the morphodynamic evolution of the sand sedimenting over its upwind slope. Finally, obtained results are condensed into a dimensionless parameter describing its sedimentation capability and compared with values resulting from other nominally two-dimensional obstacles from the literature.

• Journal of Korean Society of Forest Science
• /
• v.96 no.5
• /
• pp.561-566
• /
• 2007

This study was conducted to clarify runoff production processes in forested catchment through hydrograph separation using three-component mixing model based on the End Member Mixing Analysis (EMMA) model. The study area is located in the coniferous-forested experimental catchment, Gwangneung Gyeonggido near Seoul, Korea (N 37 45', E 127 09'). This catchment is covered by Pinus Korainensis and Abies holophylla planted at stocking rate of 3,000 trees $ha^{-1}$ in 1976. Thinning and pruning were carried out two times in the spring of 1996 and 2004 respectively. We monitored 8 successive events during the periods from June 15 to September 15, 2005. Throughfall, soil water and groundwater were sampled by the bulk sampler. Stream water was sampled every 2-hour through ISCO automatic sampler for 48 hours. The geochemical tracers were determined in the result of principal components analysis. The concentrations of $SO_4{^{2-}$ and $Na^+$ for stream water almost were distributed within the bivariate plot of the end members; throughfall, soil water and groundwater. Average contributions of throughfall, soil water and groundwater on producing stream flow for 8 events were 17%, 25% and 58% respectively. The amount of antecedent precipitation (AAP) plays an important role in determining which end members prevail during the event. It was found that ground water contributed more to produce storm runoff in the event of a small AAP compared with the event of a large AAP. On the other hand, rain water showed opposite tendency to ground water. Rain water in storm runoff may be produced by saturation overland flow occurring in the areas where soil moisture content is near saturation. AAP controls the producing mechanism for storm runoff whether surface or subsurface flow prevails.