• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.117-122
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• 2005

To find out reducing way of methane emission from a paddy field monitoring on the greenhouse gases emissions were carried out in the paddy soil with livestock compost and soil conditioner. The seasonal variations of methane emission were high at 36 days and 86 days after rice transplanting, on the other hand those of nitrous oxide emission were high at 64 days after that day. Methane emission by cow compost application, pig compost application and chicken compost application were 331, 282 and 294 kg $ha^{-1}$, respectively. Otherwise, nitrous oxide emissions by cow compost application, pig compost application and chicken compost application were 1.60, 1.78 and 1.78 kg $ha^{-1}$ respectively. The total emission rate of greenhouse gases equivalent to $CO_2$ emission rate (GWP) was 7,447 kg $ha^{-1}$ in cow compost application, 6,474 kg $ha^{-1}$ in pig compost application and 6,726 kg $ha^{-1}$ in chicken compost application. Methane emission by Ca, $SiO_2$ and artificial zeolite application were 373, 264, 239 kg $ha^{-1}$, respectively. The total emission rate of greenhouse gases equivalent to $CO_2$ emission rate (GWP) was 8,295 kg $ha^{-1}$ in Ca application 5,978 kg $ha^{-1}$ in $SiO_2$ application and 5,447 kg $ha^{-1}$ in artificial zeolite application.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.339-345
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• 2013

This study is to derive from the required performances and the optimum mix proportion of the roof concrete placed in the in-ground LNG storage tank with a capacity of 200000 $m^3$, and propose the actual data for site concrete work. The concrete placing work without sliding and segregation in the fresh concrete condition is very important because the slope of domed roof is varied in the large range by its curvature. Also the control of hydration heat and the strength development at test ages are classified with massive section about 1.4 m thick and considered to the pre-stressing work and removal of air support after concrete placing work. Considering above condition, slump range is selected $100{\pm}25$ mm under the slope $20^{\circ}$ and $150{\pm}25$ mm over the slope $20^{\circ}$ s until 60 minutes of elapsed time. Also, the roof concrete is satisfied with compressive strength range including design strength at 91 days (30 MPa), pre-stressing work at 7 days (10 MPa), air support removal work at 21 days (14 MPa). Replacement ratio of limestone powder is determined by confined water ratio test and main design factors include water-cement ratio (W/C), sand-aggregate ratio and dosage of admixture. As test results, the optimum mix proportion of the roof concrete used low heat cement is as followings. 1) Replacement ratio of limestone powder 25% by confined water ratio test 2) Water-cement ratio 57.8% 3) Sand-aggregate ratio 42.0%. Also, test results for the adiabatic temperature rising test is satisfied with its criteria and shown the lower value compared to preceding storage tank (TK-13, 14). These required performances and the optimum mix proportion is to apply the actual construction work.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.1
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• pp.8-16
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• 2024

Limestone (CaCO₃, calcium carbonate), which is used as a raw material in the portland cement and steel industry, emits CO₂ through decarbonation by high temperatures in the manufacturing process. To reduce CO₂ emissions by the use of raw materials like limestone, it has been proposed to replace limestone with various industrial by-products that contain CaO but less or none of the carbonated minerals, that cause CO₂ emissions. Loss of Ignition (LOI), Thermogravimetric analysis (TG), and Infrared Spectroscopy (IR) are used to quantitative the amount of CO₂ emission by using these industrial by-products, but CO₂ emissions can be either over or underestimated depending on the characteristics of by-product materials. In this study, we estimated CO₂ contents by LOI, TG, IR and DTG(Differential Thermogravimetric analysis) of calcite(CaCO₃) and samples that contain CO₂ in the form of carbonate and whose weight increases by oxidation at high temperatures. The test results showed for CaCO₃ samples, all test methods have a sufficient level of reliability. On the other hand, for the CO₂ content of the sample whose weight increases at high temperature, LOI and TG did not properly estimate the CO₂ content of the sample, and IR tended to overestimate compared to the predicted value, but the estimated result by DTG was close to the predicted valu e. From these resu lts, in the case of samples that contain less than a few percent of CO₂ and whose weight increases during the temperature that carbonate minerals decompose, estimating the CO₂ content using DTG is a more reasonable way than LOI, TG, and IR.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.1
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• pp.43-50
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• 1978

In order to compare the effectiveness of different phosphorus forms (pulverized as regranulized) and formulars (compound fertilizers) of fused phosphate and to compare the effectiveness of boron from different forms (straight borax, granulized with fused phosphate and included in compound fertilizer), a field experiment was conducted on a relatively fertile upland soil using soybean as a test crop. Results are summarized as following. 1. Yield of soybean was significantly higher in the plots fertilized with P when compared to check plot (no p). However, no significant differences were observed among the different forms or formulars of fused phosphate, indicating that the regranulization or formulation of compound fertilizer did not influence the effectiveness of phosphorus. 2. The application of boron, regardless of its formular, brought about higher B content in plant tissue and higher grain yield. There was a tendency that boron contained in ragranulized fused phosphate was more effective than straight borax. The results also indicated that when boron is to be included in NPK compound fertilizer, its content should be at the least 1.5% as $B_2O_3$. 3. The effectiveness of boron appeared as increased number of pod, higher B, and Ca contents in plant and the amounts of uptake of these elements by soybean. 4. The analysis of soil after the experiment indicated that different forms or formulars of fused phosphate were similarly effective in increasing the available P, Ca, and Mg contents in the soil. 5. Slight increase in available B contents in the experimental plot soils applied with boron fertilizer was observed after the trial.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.420-425
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• 2011

In general, the decomposition of $CaSO_4$ formed by sulfation reaction in the in-furnace desulfurization process using limestone has strong effect on the desulfurization reaction under the oxy-fuel combustion condition. In this study, the conversion rates were measured and reaction rates were calculated in order to investigate the effects of the experimental variables such as temperature and the concentrations of $CO_2$, $O_2$, $SO_2$, on the $CaSO_4$ decomposition reaction using DTF (Drop Tube Furnace) in the desulfurization reaction. The conversion rate and the reaction rate of $CaSO_4$ decomposition reaction were increased with reaction temperature. $CO_2$ concentration has little effect on $CaSO_4$ decomposition reaction in the presence of $O_2$. Under the same experimental conditions, the decomposition rate of $CaSO_4$ was enhanced with the decreasing the $O_2$ concentration, but vice versa with the increasing of $SO_2$ concentration.

• Korean Journal of Food Science and Technology
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• v.9 no.4
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• pp.245-250
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• 1977

Experiment were conducted to find out the effective drying method of citrus peel produced in Korea by varying the temperature of hot air, surface area of peels, peels from several citrus varieties and physicochemical treatment of the peel. 1. About $3{\sim}6\;days$ were required to reduce the moisture level of the peel from 70%(wet basis) to 20% at room temperature without forced convection. 2. Drying was speeded up until the temperature of hot air reached $60^{\circ}C$. Beyond that no significant increase in drying rate was observed. About 50 minutes were needed to reduce the moisture level (dry basis) to below 10% at $60^{\circ}C$ by forced convection 3. When the peel surface area was increased twice by cutting the peel into 256 fractions, the overall drying time (the time required to reduce the moisture level to 10%, dry basis) was shortened to 15 minutes from 50 mintes of the original peel. 4. No significant difference in drying rate was observed among the peels from several citrus varieties except Shaddock jabon and Citrus ponki tanaka, which dried more slowly than others. 5. Treatment of $Ca(OH)_2$ and the pressing of the peel before drying were effective in drying only when the initial moisture content was substantially higher.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.242-249
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• 1982

Effects of lime and ameliolating materials on decreasing available soil cadmium were studied, applying the amendments to Cd pre-and post-treated soils. Soil sttreated with Cd were placed in pots and kept under field moisture condition, summer through winter in 1981. The results of soil analysis made 40 to 60 days after the Cd treatment are as follows ; 1. Greater amount of Cd was extracted by 0.1N-HCl or 2% Citric acid than N-AcNH4 solution. More Cd was dissoluted by 0.1-HCl than 2% Citric acid. No Cd was extracted by pure water. Showing a wide variance in the amount of extractable Cd among treatments (amendments), the $N-AcNH_4$ solution seemed to be the most effective extracting solution of available soil cadmium. 2. Calcium hydroxide was the most effective materials in reducing $N-AcNH_4$ extractable Cd, followed by calcium carbonate and calcium silicate. 3. Superphosphate is also effective in reducing exchangeable cadmium. The reduction seemed to be attributed to the precipitation of cadmium phosphate. 4. The exchangeable cadmium by $N-AcNH_4$ was large in the soil pH range of 6.0 and 6.5, and it decreased as the soil pH became far apart from these values. The decrese of exchangeable Cd at low pH seemed to be related to the increase of $Mn^{+{+}}$ and that at the high pH to the precipitation as Cd-hydroxide.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.3
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• pp.72-83
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• 2015

A plant diversity, which consists of indigenous plant community with Orientla thuja community (Natural monument no. 1) in Dodong, Daegu, is identified and analyzed as ecological characteristic to consider worth plants and vegetation resource of the region. The vascular plants of Thuja orientalis community were listed as 219 taxa (3.7% of all 4,881 taxa of Korean vascular plants); 67 families, 147 genera, 199 species, 16 varieties, and 4 forms. Vulnerable species (VU) and least concerned species (LC) were recorded based on IUCN standard; Koelretueria paniculata (VU), Thuja orientalis (LC), and Exochorda serratifolia (LC). Although the study site is a non-limestone area, a total of 15 taxa of calciphilous plants were identified; Cheilanthes argentea, Hypodematium glandulosopilosum, Asplenium retamuraria, Thuja orientalis, Spiraea blumei, Smilax sieboldii, etc. A total of 4 taxa endemic plants were identified; Prunus mandshurica for. barbinervis, Lespedeza maximowiczii var. tomentella, Forythia koreana (artificial origin), and Veronica pyrethrina. Among the list, 8 taxa of naturalized plants were identified; Fallopia dentatoalalta, Rumex crispus, Nasturtium officinale, Bidens frondosa, Erigeron annuus etc. Naturalization rate (NR) was 3.6%, of all 219 taxa of vascular plants and urbanization index (UI) was 2.2% of all 321 taxa of naturalized plants. Thuja orientalis occupies a lot of indigenous landscape in this study area which is the southern-limited part of a natural distribution where it can survive. The T. orientalis community, where indigenous plants have formed a characterful species composition based on habitat, has been confirmed as a worth national vegetation resource in an indigeous flora. It has been considered of plans for persistent conservation.

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.74-82
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• 2014

A perennial plant species of Ranunculaceae, Pulsatilla tongkangensis is a very rare species only found in limestone vegetation of South Korea. It is not only rare but also has great value as a horticultural resource, thus resulting in serious problems of overexploitation and habitat disturbance. For the conservation of the rare species and its development as a resource, the study was conducted with the following three aims: first, to investigate any new geographical distribution of the species; second, to identify the site condition and vegetation structure of its habitat; and third, to compare the ecology of P. tongkangensis in other microhabitats such as rock, slope and ridge area. A new distribution was found in limestone vegetation at Danyang-gun, Chungcheongbuk-do. It was, therefore, confirmed that the distribution of P. tongkangensis exactly coincides with the area of distribution of limestone, indicating a possibility that the species might be a calcicole. 87% of the microhabitats found in rocks. Compared to P. tongkangensis, at ridges or slopes, number of P. tongkangensis plants were few in rocks. It is possibly due to the lack of microhabitats that could settle in rocky areas. Once established on rocks, however, plants grew large enough to flower with higher number of leaves and flowers per plant, resulting in higher flowering rate on rocky areas. Cracks in/between rocks are likely to be safe places for the plants with favorable light conditions, abundant fine particles to root down and reduced competition for resources. Yet, further research is necessary in terms of determining whether the species is indeed a calcicole, whether other limiting factors work in its establishment stage, and genetic diversity exists in the population.

• Tuberculosis and Respiratory Diseases
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• v.53 no.5
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• pp.510-518
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• 2002

Background : Bronchial anthracofibrosis (BAF) is a dark black or brown pigmentation of multiple large bronchi associated with a fibrotic stenosis or obliteration that is incidentally found during a diagnostic bronchoscopy some reporters have suggested endobronchial tuberculosis or tuberculous lymphadenitis as a possible cause of BAF. However, some BAF patients do not have any medical history of tuberculosis. The aim of this study was to elucidate the clinical features of simple BAF patients, which were not associated with tuberculosis. Methods : We reviewed the patients' charts retrospectiely and interviewed all BAF patients who were followed up for 1 year or more. Among the 114 BAF patients, 43 patents (38 %) had no associated tuberculosis, cancer and pneumoconiosis. The clinical characteristics, radiological findings and associated pulmonary diseases of these patients were evaluated. Results : Most patients were non-smokers, old aged, housewifes who resided in a farming village. The common respiratory symptoms were dyspnea, cough and hemoptysis. The predominant X-ray findings were a multiple bronchial wall thickening(89%), bronchial narrowing or atelectasis (76%) and a mediastinal lymph node enlargement with/without calcification (78%). Pulmonary function test usually showed mild obstructive ventilatory abnormalities but no patient showed a restrictive ventilatory pattern and the patients were frequently affected with chronic bronchitis(51%), post-obstructive pneumonia(40%) and chronic asthma(4%). Conclusion : Because BAF is frequently associated with chronic bronchitis and obstructive pneumonia as well as tuberculosis, a careful clinical evaluation and accurate differential diagnosis is more essential than empirical anti-tuberculous medication.