• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.10 no.1
• /
• pp.100-112
• /
• 2005

Soil temperature was measured from the surface to 40 cm depth at three stations with different heights in tidal flat of Gomso Bay, west coast of Korea, for one month in every season 2004 to examine the thermal structure and the variation. Mean temperature in surface layer was higher in summer and lower in winter than in lower layer, reflecting the seasonal variation of vertically propagating structure of temperature by heating and cooling from the tidal flat surface. Standard deviation of temperature decreased from the surface to lower layer. Periodic variations of solar radiation energy and tide mainly caused short term variation of soil temperature, which was also intermittently influenced by precipitation and wind. Time series analysis showed the power spectral energy peaks at the periods of 24, 12 and 8 hours, and the strongest peak appeared at 24 hour period. These peaks can be interpreted as temperature waves forced by variations of solar radiation, diurnal tide and interaction of both variations, respectively. EOF analysis showed that the first and the second modes resolved 96% of variation of vertical temperature structure. The first mode was interpreted as the heating antl cooling from tidal flat surface and the second mode as the effect of phase lag produced by temperature wave propagation in the soil. The phase of heat transfer by 24 hour period wave, analyzed by cross spectrum, showed that mean phase difference of the temperature wave increased almost linearly with the soil depth. The time lags by the phase difference from surface to 10, 20 and 40cm were 3.2,6.5 and 9.8 hours, respectively. Vertical thermal diffusivity of temperature wave of 24 hour period was estimated using one dimensional thermal diffusion model. Average diffusivity over the soil depths and seasons resulted in $0.70{\times}10^{-6}m^2/s$ at the middle station and $0.57{\times}10^{-6}m^2/s$ at the lowest station. The depth-averaged diffusivity was large in spring and small in summer and the seasonal mean diffusivity vertically increased from 2 cm to 10 cm and decreased from 10 cm to 40 cm. Thermal propagation speeds were estimated by $8.75{\times}10^{-4}cm/s,\;3.8{\times}10{-4}cm/s,\;and\;1.7{\times}10^{-4}cm/s$ from 2 cm to 10 cm, 20 cm and 40 cm, respectively, indicating the speed reduction with depth increasing from the surface.

• Journal of Korea Technology Innovation Society
• /
• v.12 no.4
• /
• pp.788-818
• /
• 2009

Renewable energy refers to solar energy, biomass energy, hydrogen energy, wind power, fuel cell, coal liquefaction and vaporization, marine energy, waste energy, and liquidity fuel made out of byproduct of geothermal heat, hydrogen and coal; it excludes energy based on coal, oil, nuclear energy and natural gas. Developed countries have recognized the importance of these energies and thus have set the mid to long term plans to develop and commercialize the technology and supported them with drastic political and financial measures. Considering the growing recognition to the field, it is necessary to analysis up-to-now achievement of the government's related projects, in the standards of type of renewable energy, management of sectional goals, and its commercialization. Korean government is chiefly following suit the USA and British policies of developing and distributing renewable energy. However, unlike Japan which is in the lead role in solar rays industry, it still lacks in state-directed support, participation of enterprises and social recognition. The research regarding renewable energy has mainly examinedthe state of supply of each technology and suitability of specific region for applying the technology. The evaluation shows that the research has been focused on supply and demand of renewable as well as general energy and solution for the enhancement of supply capacity in certain area. However, in-depth study for commercialization and the increase of capacity in industry followed by development of the technology is still inadequate. 'Cost-benefit model for each energy source' is used in analysis of technology development of renewable energy and quantitative and macro economical effects of its commercialization in order to foresee following expand in related industries and increase in added value. First, Investment on the renewable energy technology development is in direct proportion both to the product and growth, but product shows slightly higher index under the same amount of R&D investment than growth. It indicates that advance in technology greatly influences the final product, the energy growth. Moreover, while R&D investment on renewable energy product as well as the government funds included in the investment have proportionate influence on the renewable energy growth, private investment in the total amount invested has reciprocal influence. This statistic shows that research and development is mainly driven by government funds rather than private investment. Finally, while R&D investment on renewable energy growth affects proportionately, government funds and private investment shows no direct relations, which indicates that the effects of research and development on renewable energy do not affect government funds or private investment. All of the results signify that although it is important to have government policy in technology development and commercialization, private investment and active participation of enterprises are the key to the success in the industry.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.6
• /
• pp.190-197
• /
• 2012

The purpose of this study was to evaluate thermal environment and heat budget of light thin layer green roof through an experiment in order to quantify its heat budget. Two concrete model boxes($1.2m(W){\times}1.2m(D){\times}1.0m(H)$) were constructed: One experiment box with Zoysia japonica planted on substrate depth of 10cm and one control box without any plant. Between June 6th and 7th, 2012, outside climatic conditions(air temperature, relative humidity, wind direction, wind speed), evapotranspiration, surface and ceiling temperature, heat flux, and heat budget of the boxes were measured. Daily maximum temperature of those two days was $29.4^{\circ}C$ and $30^{\circ}C$, and daily evapotranspiration was $2,686.1g/m^2$ and $3,312.8g/m^2$, respectively. It was found that evapotranspiration increased as the quantity of solar radiation increased. A surface and ceiling temperature of those two boxes was compared when outside air temperature was the greatest. and control box showed a greater temperature in both cases. Thus it was found that green roof was effective in reducing temperature. As results of heat budget analysis, heat budget of a green roof showed a greater proportion of net radiation and latent heat while heat budget of the control box showed a greater proportion of sensible heat and conduction heat. The significance of this study was to analyze heat budget of green roof temperature reduction. As substrate depth and types, species and seasonal changes may have influences on temperature reduction of green roof, further study is necessary.

• Korean Journal of Plant Resources
• /
• v.25 no.4
• /
• pp.387-393
• /
• 2012

In order to improve storability of subtropical yam produced in South Korea, the major pathogens found during the storage were isolated and identified of the pathogenicity, and rot inhibition effect was studied based on the curing treatment condition. Penicillium sclerotigenum and Penicillium polonicum were identified as major pathogens causing rot in subtropical yam during storage, and P. sclerotigenum had stronger pathogenicity. Only the cut surface which has been made during a harvest and has been made smooth before curing generated a normal callus layer. The cut surface of tuberous root was cured in 95% of relativity humidity for three days at $23^{\circ}C$, and cured at $28^{\circ}C$ and $33^{\circ}C$. The observation of callus layer showed that the $23^{\circ}C$ treatment group had similar color saturation between tuberous root and pellicle, while the groups treated above $28^{\circ}C$ showed clear distinction. The generation rate of callus 0.5mm or bigger was 93 percent at $28^{\circ}C$ treatment, 96% at $33^{\circ}C$ treatment, but was 52% at $23^{\circ}C$ treatment. The conventional curing treatment group that used wind or sunlight at room temperature created little callus layer. The infection rate of pathogens according to the relative humidity inside the storage room was low at 40% and 60% of humidity, and the curing treatment period did not make a difference. When the humidity inside the storage room was 80%, all treatment groups rapidly increased the fungal pathogens. The rotten rate of each treatment was studied after 180 days during which the storage temperature was maintained at $16^{\circ}C$ and relative humidity 60%. While the rotten rate of tuberous root that has been cut in conventional curing treatment based on solar and wind was 43%, the one cured at over $28^{\circ}C$ and created the callus layer was less than 18%. While even a healthy tuberous root showed 25% of rotten rate in the traditional treatment group, the one cured at over $28^{\circ}C$ was less than 10%. The weight loss was 1-6% lower in the forced treatment group than in the conventional treatment group.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.41 no.6
• /
• pp.52-61
• /
• 2013

This study was conducted to investigate the effects of pergola's shading on the thermal comfort index in the summer. The 3 type of pergolas($4m{\times}4m{\times}h2.7m$) which were screened overhead(I)/overhead west(II)/overhead west north(III) plane with reed blind for summer shading and winter wind break, were constructed on the 4th floor rooftop. Thereafter the meteorological variables(air temperature, humidity, radiation, and wind speed) of pergola I, III and rooftop were measured from 14 to 16 August 2013(1st experiment), those of pergola I, II and rooftop were measured from 26 to 28 August 2013(2nd experiment). The effects of pergola's shading on the radiation environment and mean radiant temperature($T_{mrt}$), standard effective temperature($SET^*$) were as follows. The maximum 1 h mean values of differences ${\Delta}$ of the sums of shortwave radiant flux densities absorbed by the human body (${\Delta}K_{abs,max}$) between pergola I, III and nearby sunny rooftop were $-119W/m^2$, $-158W/m^2$, those between pergola I, II and rooftop were $-145W/m^2$, $-159W/m^2$. The maximum 1 h mean values of differences ${\Delta}$ of the sums of long wave radiant flux densities absorbed by the human body (${\Delta}L_{abs,max}$) between pergola I, III and nearby sunny rooftop, were $-15W/m^2$, $-17W/m^2$, those between pergola I, II and nearby rooftop, were $-8W/m^2$, $-7W/m^2$. The response of the direction dependent long wave radiant flux densities $L_1$ on the pergola's shading turned out to be distinctly weaker as compared to shortwave radiant flux densities $K_1$. The pergola's shading leads to a lowering of $T_{mrt}$ and $SET^*$. The peak values of $T_{mrt}$ absorbed by the human body were decreased $16^{\circ}C$ and $21.4^{\circ}C$ under pergola I and III as compared to that of nearby rooftop in the 1st experiment. Those were decreased $18.8^{\circ}C$ and $20.8^{\circ}C$ under pergola I and II as compared to that of nearby rooftop in the 2nd experiment. The peak values of $SET^*$ absorbed by the human body were decreased $2.9^{\circ}C$ and $2.6^{\circ}C$ under pergola I and III as compared to that of nearby rooftop in the 1st experiment. Those were decreased $3.5^{\circ}C$ and $2.6^{\circ}C$ under pergola I and II as compared to that of nearby rooftop in the 2nd experiment. The relative $SET^*$ decrease in pergola II, III compared to nearby sunny rooftop $SET^*$ were lower than that in pergola I, revealing the influence of the wind speed. Therefore it is essential to design pergola to maximize wind speed and minimize solar radiation to achieve comfort in the hot summer. The $SET^*$ under pergola I, III were exceeded $28.7^{\circ}C$ and $30.4^{\circ}C$ which were the upper limit of thermal comfort and tolerable zone during all most daytimes in the 1st experiment(maximum air temperature $37.5^{\circ}C$). The $SET^*$ under pergola I was exceeded $28.7^{\circ}C$ which was the upper limit of thermal comfort zone at 13h, that under pergola II was exceeded $28.7^{\circ}C$ from 8h to 14h, meanwhile the $SET^*$ under pergola I, II were within thermal tolerable zone during most daytimes in the 2nd experiment(maximum air temperature $34.4^{\circ}C$). Therefore to ensure the thermal comfort of pergola for summer hottest days, pergola should be shaded with not only reed blind but also climbing and shade plants. $T_{mrt}$ and $SET^*$ were suitable index for the evaluation of pergola's shading effects and outdoors.

• Archives of design research
• /
• v.18 no.4 s.62
• /
• pp.105-118
• /
• 2005

Housing environment for human beings has been diversified and more convenient due to the development of high technology and civilization brought by industrialization in the 20th century. In the 21st century, how to overcome the ecological limit of biased development-centered advancement, that is, how to preserve and hand over a clean and healthy 'sustainable environment' to our next generations has been one of the most-talked about issues. Environmental symbiosis means a wider range of environmental harmony from micro-dimensional perspective to macro one. The three goals of a environmentally friendly house are to preserve global environment, to harmonize with the environment around, and to offer a healthy and comfortable living environment. From the point of view of environmental symbiosis, houses should be designed to save energy and natural resources for preservation of global environment, to collect such natural energy resources as solar heat and wind force, to recycle waste water, and recycle and reduce the amount of the waste matter. Now, the environmentally-friendly house became a new social mission that is difficult to not only challenge but also realize without conversion to a new paradigm, ecologism.

• Korean Journal of Environmental Biology
• /
• v.22 no.2
• /
• pp.247-258
• /
• 2004

Climatological, hydrological and planktonical research studies, measurements of primary production and photosynthetic efficiency from December 1976 to December 1978 have been carried out in two brackish lakes: Lake Etang de Berre and Lake Etang de Vaine located in the French Mediterranean coast, in the region of Carry-le-Rouet located on the north-west Mediterranean near Marseilles, and in fresh water inflows from 4 Rivers (Touloubre, Durance, Arc, Durancole) to Lake Etang de Berre. Physico-chemical parameters were measured for this study: water temperature, salinity, density, pH, alcalinity, dissolved oxygen (% saturation), phosphate, nitrate, nitrite, silicate etc. Diverse biological parameters were also studied: photosynthetic pigments, phaeopigments, specific composition and biomass of phytoplankton, primary pelagic production etc. Climatical factors were studied: air-temperature, solar-radiation, evaporation, direction (including strength) of winds, precipitation and freshwater volume of the four rivers. The changes in Lake ‘Etang de Berre’ ecosystem depend on the quality of the water in the Durance River, and on the effects of seawater near the entrance of the Caronte Canal. The water quality of the lake varies horizontally and vertically as a result of atmospheric phenomena, maritime currents and tides. The distribution of water temperatures is generally heterogeneous. Southeasterly winds and the Northeasterly Mistral wind are important in the origins of circulated and mixed water masses. These winds are both frequent and strong. They have, as a result, a great effect on the water environment of Lake Etang de Berre. In theory, the annual precipitation in this region is well over eight times the water mass of the lake. The water of the Durance River flows into Lake Etang de Berre through the EDF Canal, amounting to 90% of the precipitation. However, reduction of rainfall in dry seasons has a serious effect on the hydrological characteristics of the lake. The temperature in the winter is partially caused by the low temperature of fresh water, particularly that of the Durance River. The hydrological season of fresh and brackish water is about one month ahead of the hydrological season of sea water in its vicinity. The salinity of Lake Etang de Berre runs approximately 3$\textperthousand$, except at lower levels and near the entrance to the Caronte Canal. However, when the volume of the Durance River water is reduced in the summer and fall, the salinity rises to 15$\textperthousand$. In the lake, the ratio of fresh water to sea water is six to one (6:1). The large quantities of seston conveyed by rivers, particularly the Durance diversion, strongly reduce the transparency in the brackish waters. Although the amount of sunshine is also notable, transparency is slight because of the large amount of seston, carried chiefly by Tripton in the fresh water of the Durance River. Therefore, photosynthesis generally occurs only in the surface layer. The transparency progressively increases from freshwater to open seawater, as mineral particles sink to the bottom (about 1.7kg $m^{-2}a^{-1}$ on the average in brackish lakes). The concentration of dissolved oxygen and the rate of oxygen saturation in seawater (Carry-le-Rouet) ranged from 5.0 to 6.0 $m\ell$ㆍ.$1^{-1}$, and from 95 to 105%, respectively. The amount of dissolved oxygen in Etang de Berre oscillated between 2.9 and 268.3%. The monographs of phosphate, nitrate, nitrite and silicate were published as a part of a study on the ecology of phytoplankton in these environments. Horizontal and vertical distributions of these nutriments were studied in detail. The recent diversion of the Durance River into Lake Etang de Berre has effected a fundamental change in this formerly marine environment, which has had a great impact in its plankton populations. A total of 182 taxa were identified, including 111 Bacillariophyceae, 44 Chlorophyceae, and 15 Cyanophyceae. The most abundant species are small freshwater algae, mainly Chlorophyceae. The average density is about $10^{8}$ cells $1^{-1}$ in Lake Etang de Berre, and about double that amount in Lake Etang de Vaine. Differences in phytoplankton abundance and composition at the various stations or at various depths are slight. Cell biovolume V (equivalent to true biomass), plasma volume VP (‘useful’ biomass) and, simultaneously. the cell surface area S and S/V ratio through the measurement of cell dimensions were computed as the parameters of phytoplankton productivity and metabolism. Pigment concentrations are generally very high on account of phytoplankton blooms by Cyanophyceae, Chlorophyceae and Cryptophyceae. On the other hand, in freshwaters and marine waters, pigment concentrations are comparatively low and stable, showing slight annual variation. The variations of ATP concentration were closely related to those of chlorophyll a and phytoplankton blooms only in marine waters. The carbon uptake rates ranged between 38 and 1091 mg$Cm^{-2}d^{-1}$, with an average surface value of 256 mg; water-column carbon-uptake rates ranged between 240 and 2310 mg$Cm^{-2}d^{-1}$, with an average of 810, representing 290 mg$Cm^{-2}$, per year 45 000 tons per year of photosynthetized carbon for the whole lake. Gross photosynthetic production measured by the method of Ryther was studied over a 2-year period. The values obtained from marine water(Carry-le-Rouet) ranged from 23 to 2 337 mg$Cm^{-2}d^{-1}$, with a weighted average of 319, representing about 110 gCm$^{-2}$ per year. The values in brakish water (Etang de Berre) ranged from 14 to 1778 mg$Cm^{-2}d^{-1}$, with a weighted average of 682, representing 250 mg$Cm^{-2}$ per year and 38 400 tons per year of photosynthesized carbon for the whole lake.

• Korean Journal of Soil Science and Fertilizer
• /
• v.15 no.4
• /
• pp.213-220
• /
• 1982

Soil water changes in lysimeters with four different soils and two different available soil depths were monitored during the growing seasons of the soybean-barley cropping from 1977 to 1980 in Suweon to evaluate evapotranspiration (ET) as a function of available soil water and evaporative demand of the atmosphere. ET was calculated with soil water profile and water balance. Soil water content was measured with a neutron moisture depth gauage and The evaporative demand of the atmosphere was estimated with a class A pan evaporation. Rainfall. solar radiation, and wind speed were observed to examine heat and water balances. The average ET of soybeans ranged from 1.6 mm/day at seedling to 6.5 mm/day at flowering, and that of barley ranged from 0.5 mm/day at the regrowth stage to 4.6 mm/day at heading; however, a large variability was observed. The ratio of ET to pan evaporation ($ET/E_o$) ranged from 0.5 to 1.1 for soybeans and 0.4 to 1.2 for barley. The soil evaporation factor ($K_e$) of the $ET/E_o$ component decreased as the soil water depleted and the canopy developed. The crop transpiration factor ($K_t$), another component of $ET/E_o$, also was a function of time and the soil water. $K_t$ was constant when the available soil water fraction (f) in the root zone was greater than a threshold value, and $K_e$ was decreased linearly when f was lower than this threshold. The threshold was 0.7 for the moderate evaporative demand days, 0.4 to 0.5 for the low evaporative demand days, and 0.9 to 0.96 for the high evaporative demand days. Conclusively, the ET can be estimated from the evaporative demand of the atmosphere, $E_o$, $K_e$ and $K_t$, and the available soil water content in the root zone.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.2
• /
• pp.252-263
• /
• 1997

Temperature and salinity were observed in Kugum Suro Channel in February, April, August and October 1993. Temperature ranged from $7.0^{\circ}C\;to\;25.0^{\circ}C$ throughout the year and its variation was about $18^{\circ}C$. The maximum temperature difference between surface and bottom was less than $0.75^{\circ}C$ for a year, which meant that the temperature stratification in Kugum Suro Channel was considerably week. Salinity had also a small variation range of less than $0.5\%_{\circ}$. Salinity varied from $34.0\%_{\circ}$ in April to $30.0\%_{\circ}$ in August and its fluctuation patterns were quite similar to the seasonal variations of the precipitation and the duration of sunshine observed at Kohung Weather station. Seasonal variation of sea water density in T-S diagram showed that the water mass in Kugum Suro Channel could be largely affected by regional atmospheric conditions. Temperature increased in ebb tide and decreased in flood tide, but salinity decreased in ebb tide and increased in flood tide for a day. The period of fluctuations in temperature and salinity measured for 25 hours was nearly coincident with the semi-diurnal tide which was predominant in that region. Stratification parameters computed in Kugum Suro Channel areas were less than $4.0J/m^3$ the year round, which indicated that vortical mixing from the bottom boundary caused by tidal current played an important role in deciding the stratification regime in Kugum Suro Channel. In estimating the equation which defines stratification and mixing effects in the observed areas, the tidal mixing term ranged from $4.7J/M^3\;to\;14.1J/m^3$ was greater than any other terms like solar radiation, river discharge and wind mixing.

• Journal of Energy Engineering
• /
• v.23 no.4
• /
• pp.31-40
• /
• 2014

The Korean government made the 2nd Energy Basic Plan to achieve 11% of new and renewable energies distribution rate until 2035 as a response to cope with international discussion about greenhouse gas emission reduction. Renewable energies include solar thermal, photovoltaic, bioenergy, wind power, small hydropower, geothermal energy, ocean energy, and waste energy. New energies contain fuel cells, coal gasification and liquefaction, and hydrogen. As public and private investment to enhance the distribution of new and renewable energies, it is necessary to clarify the economic effects of the new and renewable energies sector. To the end, this study attempts to apply an input-output analysis and analyze the economic effects of new and renewable energies sector using 2012 input-output table. Three topics are dealt with. First, production-inducing effect, value-added creation effect, and employment-inducing effect are quantified based on demand-driven model. Second, supply shortage effects are analyzed employing supply-driven model. Lastly, price pervasive effects are investigated applying Leontief price model. The results of this analysis are as follows. First, one won of production or investment in new and renewable energies sector induces 2.1776 won of production and 0.7080 won of value-added. Moreover, the employment-inducing effect of one billion won of production or investment in new and renewable energies sector is estimated to be 9.0337 persons. Second, production shortage cost from one won of supply failure in new and renewable energies sector is calculated to be 1.6314 won, which is not small. Third, the impact of the 10% increase in new and renewable energies rate on the general price level is computed to be 0.0123%, which is small. This information can be utilized in forecasting the economic effects of new and renewable energies sector.