• Korean Journal of Agricultural and Forest Meteorology
• /
• v.15 no.3
• /
• pp.130-144
• /
• 2013

In this study, we examined the effect of high temperature of urban area on the physiological response of apple tree including the photosynthesis, shoot growth, and fruit quality of 'Fuji'/M.9 apple trees planted at Daegu urban area (DUA) and Gunwi rural area (GRA) for 2 years (2009-2010). During the apple growing season (April-October), the average air temperature of DUA was about $3.0^{\circ}C$ higher than that of GRA and the total rainfall of DUA was 130 mm more than that of GRA. During fruit enlargement stage (June-August), the number of days that recorded daily mean temperature of over $30^{\circ}C$ were ten on DUA in 2010, but there was no day when such temperature was experienced in 2009. Average air temperature of DUA during the maturation stage (September-October) was $19.8^{\circ}C$, which was $4.0^{\circ}C$ higher than that of GRA. The higher temperature of over $30^{\circ}C$ during fruit enlargement stage decreased the photosynthetic rate, shoot growth, fruit weight, and soluble solid content of 'Fuji'/M.9 apple tree. The moderate temperature of about $20^{\circ}C$ during maturation stage increased the photosynthetic rate and soluble solid content of 'Fuji'/M.9 apple tree, but decreased fruit red color. In regional comparison with GRA, photosynthetic rate of DUA was changed from lower before rainy season to higher after rainy season. Fruit weight was higher in DUA than that of GRA. However, fruit weight between DUA and GRA did not show the difference when accumulated days that recorded daily maximum temperature over $35^{\circ}C$ of DUA was increased. Compared to the GRA, soluble solid content of DUA was higher, but fruit red color of DUA was less. These results indicate that the poor red coloring is the most problematic in 'Fuji'/M.9 apple tree by global warming and urbanization.

• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.6
• /
• pp.502-509
• /
• 2013

To estimate greenhouse gas (GHG) emission, we established inventory of conventional rice cultivation from farmers in Gunsan and Iksan, Jeonbuk province in 2011~2012. This study was to calculate carbon footprint and to analyse the major factor of GHGs. We carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we tried to suggest agricultural methods to reduce GHGs that farmers of this case study can apply. Carbon footprint of rice production unit of 1 kg was 2.21 kg $CO_2.-eq.kg^{-1}$. Although amount of $CO_2$ emissions is largest among GHGs, methane had the highest contribution of carbon footprint on rice production system after methane was converted to carbon dioxide equivalent ($CO_2$-eq.) multiplied by the global warming potential (GWP). Source of $CO_2$ in the cultivation of rice farming is incomplete combustion of fossil fuels used by agricultural machinery. Most of the $CH_4$ emitted during rice cultivation and major factor of $CH_4$ emission is flooded paddy field in anaerobic condition. Most of the $N_2O$ emitted from rice cultivation process and major sources of $N_2O$ emission is application of fertilizer such as compound fertilizer, urea, orgainc fertilizer, etc. As a result of sensitivity analysis due to the variation in energy consumption, diesel had the highest sensitivity among the energies inputs. If diesel consumption is reduced by 10%, it could be estimated that $CO_2$ potential reduction is about 2.5%. When application rate of compound fertilizer reduces by 10%, the potential reduction is calculated to be approximately 1% for $CO_2$ and approximately 1.8% for $N_2O$. When drainage duration is decreased until 10 days, methane emissions is reduced by approximately 4.5%. That is to say drainage days, tillage, and reducing diesel consumption were the main sources having the largest effect of GHG reduction due to changing amount of inputs. Accordingly, proposed methods to decrease GHG emissions were no-tillage, midsummer drainage, etc.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.11
• /
• pp.611-617
• /
• 2016

Remanufacturing that is the rebuilding of a product to specifications of the original manufactured product by collecting used-product, completely disassembling, cleaning and repairing or replacing with a new part and reassembling has been received attention in aspects of resource, recycling because it is a great environmental improvement. Remanufacturing is the rebuilding of a product to specifications of the original manufactured product by collecting used-product, completely disassembling, cleaning and repairing or replacing with a new part and reassembling. With a great environmental improvement and resource recycling and conservation, many studies were conducted. Up to date, remanufacturing activities are mainly applied to automobile parts and printer toner cartridge in South Korea. However, remanufacturing of rental product is not well conducted although rental products are collected in good condition and could be remanufactured in the same condition as a new product. Therefore, in this study, we conducted life cycle assessment (LCA) to an air cleaner product that is one of rental products. This study attempts to identify the processes in new products and remanufacturing life cycles that contribute the most environmental impacts. The results show that air cleaner remanufacturing could reduce about 20% of environmental impacts compared to new product. The greatest benefit related to environmental impact is with regard to ozone layer depletion potential (ODP), which is reduced by 94%. In the life cycle of air cleaner, raw material extraction stage had the most environmental impacts, especially with regard to abiotic depletion potential (ADP) and global warming potential (GWP). In the environmental impacts in each part, the ABS power had the highest environmental impacts.

• Korean Chemical Engineering Research
• /
• v.50 no.6
• /
• pp.1002-1007
• /
• 2012

The considerable portion of energy demand has been satisfied by the combustion of fossil fuel and the consequent $CO_2$ emission was considered as a main cause of global warming. As a technology option for $CO_2$ emission mitigation, absorption process has been used in $CO_2$ capture from large scale emission sources. To set up optimal operating parameters in $CO_2$ absorption and solvent regeneration units are important for the better performance of the whole $CO_2$ absorption plant. Optimal operating parameters are usually selected through a lot of actual operation data. However theoretical approach are also useful because the arbitrary change of process parameters often limited for the stability of process operation. In this paper, a theoretical approach based on vapor-liquid equilibrium was proposed to estimate optimal operating conditions of $CO_2$ absorption process. Two $CO_2$ absorption processes using 12 wt% aqueous $NH_3$ solution and 20 wt% aqueous MEA solution were investigated in this theoretical estimation of optimal operating conditions. The results showed that $CO_2$ loading of rich absorbent should be kept below 0.4 in case of 12 wt% aqueous $NH_3$ solution for $CO_2$ absorption but there was no limitation of $CO_2$ loading in case of 20 wt% aqueous MEA solution for $CO_2$ absorption. The optimal regeneration temperature was determined by theoretical approach based on $CO_2$ loadings of rich and lean absorbent, which determined to satisfy the amount of absorbed $CO_2$. The amount of heating medium at optimal regeneration temperature is also determined to meet the difference of $CO_2$ loading between rich and lean absorbent. It could be confirmed that the theoretical approach, which accurately estimate the optimal regeneration conditions of lab scale $CO_2$ absorption using 12 wt% aqueous $NH_3$ solution could estimate those of 20 wt% aqueous MEA solution and could be used for the design and operation of $CO_2$ absorption process using chemical absorbent.

• Journal of Climate Change Research
• /
• v.4 no.2
• /
• pp.77-93
• /
• 2013

Global warming accelerates both carbon (C) input through increased forest productivity and heterotrophic C emission in forest soils, and a future trend in soil C dynamics is uncertain. In this study, the Korean forest soil carbon model (KFSC model) was applied to 1,467,458 ha of Pinus densiflora forests in Korea to predict future C dynamics under RCP 8.5 climate change scenario (RCP scenario). Korea was divided into 16 administrative regions, and P. densiflora forests in each region were classified into six classes by their stand ages : 1 to 10 (I), 11 to 20 (II), 21 to 30 (III), 31 to 40 (IV), 41 to 50 (V), and 51 to 80-year-old (VI+). The forest of each stand age class in a region was treated as a simulation unit, then future net primary production (NPP), soil respiration (SR) and forest soil C stock of each simulation unit were predicted from the 2012 to 2100 under RCP scenario and constant temperature scenario (CT scenario). As a result, NPP decreased in the initial stage of simulation then increased while SR increased in the initial stage of simulation then decreased in both scenarios. The mean NPP and SR under RCP scenario was 20.2% and 20.0% higher than that under CT scenario, respectively. When the initial age class was I, IV, V or VI+, predicted soil C stock under CT scenario was higher than that under RCP scenario, however, the countertrend was observed when the initial age class was II or III. Also, forests having a lower site index showed a lower soil C stock. It suggested that the impact of temperature on NPP was higher when the forests grow faster. Soil C stock under RCP scenario decreased at the end of simulation, and it might be derived from exponentially increased SR under the higher temperature condition. Thus, the difference in soil C stock under two scenarios will be much larger in the further future.

• Horticultural Science & Technology
• /
• v.34 no.5
• /
• pp.665-676
• /
• 2016

As high temperature during citrus growing season has caused a serious problems including inferior coloration in production of mandarins in Korea, we were to investigate the expression pattern of several genes related with coloration during the ripening in high temperature condition of citrus fruits. The expression of genes related with sugar metabolism, cell wall degradation, and flavonoid synthesis in high temperature conditions was investigated in fruits of 'Haryejosaeng' (Citrus unshiu) and 'Shiranuhi' mandarin (C. reticulata). While the expression of beta-amylase (BMY), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), and flavanone 3-hydroxylase (F3H) was differently induced, expression of polygalacturonase (PG) decreased dependently on temperature conditions. In 'Haryejosaeng' mandarin, while the expression of genes related to the skin coloration, such as CHS and F3H genes increased at $25^{\circ}C$, the expression of PAL and stilbene synthase (STS) genes were induced at $30-35^{\circ}C$ in all ripening stages. In 'Shiranuhi' mandarin, the expression of the BMY gene decreased at early time point in all temperature condition and then increased at $30-35^{\circ}C$ than at $25^{\circ}C$ in the ripening stage 2 to 3 of fruits. F3H and STS genes also showed the tendency to decrease at $30-35^{\circ}C$. Although the expression levels of genes in ripening stage 1 and stage 2 of fruits showed similar patterns in both 'Haryejosaeng' and 'Shiranuhi', the expression levels of genes were down-regulated in late ripening stage of 'Shiranuhi' fruits compared to 'Haryejosaeng'. In general, the mRNA levels of seven tested genes were higher in 'Haryejosaeng' than in 'Shiranuhi' mandarin, and expression of genes by high temperature was regulated sensitively in 'Haryejosaeng' compared to 'Shiranuhi' mandarin. Further investigations of expression of various genes based on transcriptome analysis in early ripening stage can provide valuable information about the responses to climatic changes in ripening citrus fruits.

• Korean Journal of Ecology and Environment
• /
• v.46 no.2
• /
• pp.289-300
• /
• 2013

Forest vegetation of Hyangjeokbong (1,614 m) in Deogyusan National Park is classified into mountain forest vegetation and flatland forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, valley forest, coniferous forest, subalpine coniferous forest, shrub forest, grassland forest, afforestation and etc., while riparian forest was found under the category of flatland forest vegetation. Including 122 communities of mountain forest vegetation and 2 communities of riparian forest, the total of 124 communities were researched; the distributed colonies classified by physiognomy classification are 42 communities deciduous broad-leaved forest, 37 communities of valley forest, 8 communities of coniferous forests, 6 communities of subalpine coniferous forest, 3 communities of shrub forest, 1 communities of grassland forest, 21 afforestation and 4 other communities. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus serrata, Quercus variabilis communities account for 47.02 percent of deciduous broad-leaved forest, Fraxinus mandshurica community takes up 57.48 percent of mountain valley forest, Pinus densiflora community holds 77.53 percent of mountain coniferous forest holds, and Taxus cuspidate-Abies koreana community takes up about 50 percent of subalpine coniferous forest. Mountain shrub forest and mountain grassland forest vegetation are concentrated mainly on the top of Hyangjeokbong and the ridge connecting the top and Jungbong. Meanwhile, riparian forest vegetation comprises 0.024% of the whole vegetation area in a study area. In conclusion, minority species consisting of Quercus mongolica, Quercus serrata, Quercus variabilis, Fraxinus mandshurica, Cornus controversa, Pinus densiflora, Abies koreana and Taxus cuspidata are distributed as dominant species of the uppermost part in a forest vegetation region in Deogyusan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Carpinus laxiflora and Fraxinus mandshurica which are climax species in the area. However, in respect of subalpine coniferous forest, the distribution rate of deciduous broad-leaved forest seems to increase gradually due to global warming and artificial disturbance.

• Journal of The Korean Association For Science Education
• /
• v.37 no.1
• /
• pp.9-16
• /
• 2017

The result of TIMSS 2015 was announced at the end of 2016. In this research, we conducted test-curriculum matching analysis for 8th grade earth science and analyzed Korean students' percentage of correct answers and responses for TIMSS earth science test items. According to the results, Korean students showed high percentage of correct answers when the item topics are covered in the 2009 revised science curriculum, and Korean students revealed their weakness in constructed response items since the percentage for correct answers on constructed response items is half that of multiple choice items. Depending on the earth science topic, for 'solid earth' area, which includes earth's structure and physical features, as well as earth's processes and history, students showed high percentage of correct answers for multiple choice items. Students, however, showed low percentage of correct answers for items that require applying knowledge to everyday situations and connecting with other areas of science such as biology. For 'atmosphere and ocean' areas, which include earth's processes and cycles, students showed low percentage of scores for climate comparison between regions, features of global warming, etc. For the area of 'universe', students showed high percentage of scores for the earth's rotation and revolution, the moon's gravity, and so on because they have learned these topics since primary school. Discussed in the conclusion are ways to secure content connection between the primary and middle school earth science curriculums, ways to develop students' science-inquiry related competencies, and so on to improve middle school earth science curriculum as well as teaching and learning.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.346-352
• /
• 2020

Currently, many studies are being conducted to cope with climate changes due to global warming and abnormal weather. The objective of this study was to investigate the effects of weather on the growth, yield components, and quality of soybeans using weather data from 2017 and 2018. The average temperature in 2018 was higher than that in 2017 from R1 to R5 of the growth stage for all cultivars. On the other hand, precipitation in 2018 was reduced compared to that in 2017 for Daewon and Daepung-2ho. It was observed that the flowering date in 2018 was earlier than that in 2017 for Daewon and Daepung-2ho, but the flowering date for Pungsannamul in 2018 was similar to that in 2017. Simulating soil water content with the estimation model (AFKAE0.5) determined that there were fewer drought dates in 2017 than those in 2018, and drought lasted from R1 to early R5 of the growth stage in 2018. Soybean growth in 2017 was better than that in 2018, and seed yield and 100-seed weight of soybean were higher in 2017 than those in 2018 for all cultivars. The seed size in 2017 was larger than that in 2018 for all cultivars. Oil content in 2017 was higher than that in 2018; in particular, the difference between both years was observed for Daewon and Daepung-2ho. Protein content was higher in 2018 than that in 2017; however, there were different levels for each cultivar. Thus, these results indicate that the yield component and quality of soybeans are affected by high temperature and drought.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.4
• /
• pp.338-346
• /
• 2017

Natural seaweed beds and habitat environments were investigated using quantitative and qualitative methods from May to December 2015 at 3 sites in Gangneung, Uljin, and Busan along the eastern coast of Korea. In total, 9 green, 23 brown, and 64 red algal taxa were identified. The biomass of the seaweed at Gangneung was 173.2 to $613.8wet\;wt.g/m^2$ of Dictyota divaricata, 360.8 to $520.4wet\;wt.g/m^2$ of Symphyocladia linearis, and 25.9 to $470.8wet\;wt.g/m^2$ of Undaria pinnatifida. At Uljin, these numbers were 5.5 to $256.2wet\;wt.g/m^2$ of Plocamium telfarirae and 46.8 to $241.5wet\;wt.g/m^2$ of Agarum clathratum. The biomass of Sargassum coreanum and Ecklonia cava were 388.1 to $6,972.4wet\;wt.g/m^2$ and 194.9 to $958.5wet\;wt.g/m^2$, respectively, at Busan. S. coreanum and E. cava showed higher biomass compared to other seaweed at Busan. The biomass rate represented an average of 19.2 percent of the total population, ranging from 0.0 to 55.5 percent in Gangneung. In Uljin, the average was calculated as 63.8 percent, and this figure was 48.5 percent in Busan. The percentage of barren ground averaged 46.7 percent in Gangneung and 91.1 percent in Uljin. Uljin showed the highest percentage of barren ground compared to other regions. Sea urchin density appeared to be $6.0ind./m^2$ in Gangneung, $7.0ind./m^2$ in Uljin, and $2.0ind./m^2$ in Busan, with the lowest sea urchin density being that of Busan. In conclusion, the composition of species, appearance ratio, and abundance of vegetation found were similar to previous studies, but it is thought that continuous monitoring is needed due to concerns about physical and chemical pollution caused by global warming, climate change, and coastal development.