• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.1
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• pp.4312-4322
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• 1977

In order to investigate the effect of the water content and the accelerated curing on the strength of the soil-cement mixtures, laboratory test of soil cement mixtures was performed at five levels of water content, four levels of accelerated curing temperatures, three levels of normal curing periods, and six levels of accelerated curing time. Also this study was carried out to investigate the effect of grain size distribution of 21 types of soils on the strength of soil-cement mixtures at four levels of cement content and three levels of curing time. The results are summarized as follows: 1. Optimum moisture content increased with increase of the cement content, but maximum dry density was changed ununiformly with cement content. Water content corresponding to the maximum strength was a little higher than the optimum moisture content along the increase of cement content. 2. In molding the specimens with the optimum moisture content, the maximum strength appeared at the wet side of the optimum moisture content. 3. According to increase of curing temperature as 30, 40, 50, and 60$^{\circ}C$, unconiiend compressive strength of soil-cement mixtures increased, the rate of increase at the early curing period was large, and approximately 120 hours was suifficient to harden soil-cement mixtures completely. 4. The strength of soil-cement mixtures at the curing temperature of 10$^{\circ}C$ decreased at the rate of 30 to 50 percent than at the curing temperature of 20$^{\circ}C$, and the strength of soil-cement mixtures at the curing temperature of 0$^{\circ}C$ increased a little with increase of curing time. 5. Although the strength of soil-cement mixtures seemed to be a little affected by the temperature difference between day time and night, it was recommended that reasonable working period was the duration from July to August of which average maximum temperature of Korea was approximately 30$^{\circ}C$. 6. Accelerated curing time corresponding to the normal curing time of 28-day was shorten with increase of curing temperature, also it was a little affected by the cement. Accelerated curing time that the strength of soil-cement mixtures for the cement of 9 percent and the curing temperature of 60was shorten with increase of curing temperature, also it was a little affected by the cement. Accelerated curing time that the strength of soil-cement mix- tures for the cement of 9 percent and the curing temperature of 60$^{\circ}C$ was 45 hours at the KY sample, 50 hours at the MH, 40 hours at the SS, and 34 hours at the JJ respectively. 7. Accelerated curing time was depended upon the grain size distribution of soil, it decreased with increase the percent passing of No. 200 sieve. 8. Relationship between the normal curing times and the accelerated curing times showed that there was a linear relationship between them, its slope decreased with increase of curing temperature. 9. The most reasonable soil of the soil-cement mixtures was the sandy loam which was a well graded soil. Assuming the base of road requiring 7-day strength of 21 kg/$\textrm{cm}^2$ being used, the soil-cement mixtures could be obtained with adding 6 percent of cement in such a sails S-7, S-8, S-9, S-10, S-11, S-12, S-13. 10. The regression equation between the 28-day and the 7-day strength was obtained as follow; q28=1.12q7,+6.5(r=0.96).

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.32-37
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• 2000

Because the household garbage had high water contents, it is difficult to compost it without an additive. Therefore, this study was performed to investigate possibility of using the waste newspapers as a humidity conditioner for the household garbage composting. The maximum temperature was $66.0^{\circ}C$ in spring, $69.2^{\circ}C$ in summer, $60.9^{\circ}C$ in fall and $56.0^{\circ}C$ in winter for composting periods. The seasonal pH value reached around 8.5 after 1 week and then repeated fluctuation at the narrow range in spring and fall, while it was stabilized at the range of $8{\sim}9$ after increasing to 8.5 after 1 week in winter. The water content was reduced little in winter, while decreased significantly in the other seasons. The water content after 8 weeks was 22.2% in spring, 47.6% in summer, 25.5% in fall and 72.5% in winter. The mass was reduced rapidly during the first week of each season, but it did not show much decrease. The volume reduced after 8 weeks to 59%, 32%, 27%, and 34% in spring, summer, fall and winter respectively. Organic matter content decreased over the four seasons. Nitrogen contents were in the range of 0.7% to 2.2% during the four seasons. The contents of inorganic compounds based on dry matyter were in the range of $0.94{\sim}2.59%\;P_2O_5$, $1.23{\sim}1.87%\;CaO$, $0.37{\sim}0.46%\;MgO$, $0.55{\sim}1.98%\;K_2O$. Concentration of heavy metals(Hg, Cd, Pb, Cu, Cr, Zn, As) based on dry matter were less than the limiting value of the by-product compost.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.153-159
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• 2011

BACKGROUND: This experiment was conducted to investigate the distribution and burden characteristics of heavy metal in the rainwater sampled at Taean area, in the middle part of Korea, from April 2002 to October 2003. METHODS AND RESULTS: The relationship between concentration of heavy metal and other chemical properties in the rainwaters was also evaluated. Chemical properties in the rainwater were various differences with raining periods and years. It appeared that a weighted average pH values of rainwater was ranged from 5.0 to 5.1. Heavy metal concentrations in the rainwater were ranked as Pb > Zn > Cu > Ni > As > Cr > Cd. As compared with heavy metal concentrations of rainwater in 2002, Cu, Pb, and Zn were higher than other elements in 2003. There were positive correlation between major ionic components, such as ${NH_4}^+$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$, ${SO_4}^{2-}$ and ${NO_3}^-$, and As, Cd, Zn, Cr, and Ni concentrations in rainwater. For heavy metal distribution of rainwater, the order of average enrichment factor was Cd > Pb > As > Cu > Zn > Ni > Cr, and these were relatively higher than the natural components such as Fe, Mg and Ca. The monthly enrichment factor were relatively high, from August to October at Taean. The monthly amount of heavy metal precipitation was high in the rainy season from July to August because of great influence of rainfall. CONCLUSION(s): The results of this study suggest that the heavy metals(Cd, Pb, As, Cu, and Zn) of rainwater is strongly influenced by anthropogenic sources rather than natural sources.

• Korean Journal of Remote Sensing
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• v.23 no.2
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• pp.145-152
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• 2007

The polarimetric backscattering coefficients of a wet-land rice field which is an experimental plot belong to National Institute of Agricultural Science and Technology in Suwon are measured using ground-based polarimetric scatterometers at 1.8 and 5.3 GHz throughout a growth year from transplanting period to harvest period (May to October in 2006). The polarimetric scatterometers consist of a vector network analyzer with time-gating function and polarimetric antenna set, and are well calibrated to get VV-, HV-, VH-, HH-polarized backscattering coefficients from the measurements, based on single target calibration technique using a trihedral corner reflector. The polarimetric backscattering coefficients are measured at $30^{\circ},\;40^{\circ},\;50^{\circ}\;and\;60^{\circ}$ with 30 independent samples for each incidence angle at each frequency. In the measurement periods the ground truth data including fresh and dry biomass, plant height, stem density, leaf area, specific leaf area, and moisture contents are also collected for each measurement. The temporal variations of the measured backscattering coefficients as well as the measured plant height, LAI (leaf area index) and biomass are analyzed. Then, the measured polarimetric backscattering coefficients are compared with the rice growth parameters. The measured plant height increases monotonically while the measured LAI increases only till the ripening period and decreases after the ripening period. The measured backscattering coefficientsare fitted with polynomial expressions as functions of growth age, plant LAI and plant height for each polarization, frequency, and incidence angle. As the incidence angle is bigger, correlations of L band signature to the rice growth was higher than that of C band signatures. It is found that the HH-polarized backscattering coefficients are more sensitive than the VV-polarized backscattering coefficients to growth age and other input parameters. It is necessary to divide the data according to the growth period which shows the qualitative changes of growth such as panicale initiation, flowering or heading to derive functions to estimate rice growth.

• The Journal of Korean Obstetrics and Gynecology
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• v.30 no.4
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• pp.18-44
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• 2017

Purpose: The object of this study was to observe the anti-climacterium activity of Gagamguibiondam-tang (GGOT) on ovariectomized (OVX) rats, a well-documented rodent models resembles with women postmenopausal climacterium symptoms, as including cardiovascular diseases, obesity, hyperlipidemia, osteoporosis, organ steatosis and mental disorders. Methods: In this study, anti-climacteric effects were evaluated separated into three categories; 1) anti-obese, 2) anti-uterine atrophy and 3) anti-osteoporotic effects. Five groups were used (8 rats in each group); sham control, OVX control, GGOT 500, 250 and 125 mg/kg administered groups. Twenty-eight days after bilateral OVX surgery, GGOT were orally administered, once a day for 84 days, and then the changes on the body weight and gain during experimental periods, serum estradiol levels, abdominal fat pad and uterus weights with histopathology of abdominal fat pads (total thickness and mean adipocyte diameters) and uterus (total, epithelial and mucosal thickness, percentages of uterine gland regions) for anti-obese and estrogenic effects. In addition, femur, tibia and fourth or fifth lumbar vertebrae (L4 or L5) wet, dry and ash weights, mineral density (BMD), bone strength (failure load), serum osteocalcin and bone specific alkaline phosphatase (bALP) contents, histological and histomorphometrical analyses - bone mass and structure with bone resorption, were monitored for anti-osteoporosis activity. Results: As a result of OVX, noticeable increases of body weight and gains, food and water consumption, weights of abdominal fat pad deposited in dorsal abdominal cavity, serum osteocalcin levels were demonstrated in this experiment with decrease of uterus, femur, tibia and L5 weights, serum bALP and estradiol levels. In addition, marked hypertrophic changes of adipocytes located in deposited abdominal fat pads, uterine disused atrophic changes, decreases of bone mass and structures of femur, tibia and L4 were also observed in OVX control rats with dramatic increases of bone resorption markers, the Ocn and OS/BS at histopathological and histomorphometrical analysis in this study as compared with sham-operated control rats, suggesting the estrogen-deficient climacterium symptoms - obese and osteoporosis were induced by OVX, respectively. However, these estrogen-deficient climacterium symptoms induced by bilateral OVX in rats were significantly inhibited by 84 days of continuous oral treatment of GGOT 500, 250 and 125 mg/kg, respectively. Especially, GGOT 500, 250 and 125 mg/kg showed clear dose-dependent inhibitory activities on the OVX-induced climacterium signs. Conclusion: The results suggest that oral administration of GGOT 500, 250 and 125 mg/kg has clear dose-dependent favorable anti-climacterium effects - estrogenic, anti-obese and anti-osteoporotic activities in OVX rats in this experiment.

• The Korean Journal of Mycology
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• v.7 no.1
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• pp.13-73
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• 1979

These studies were conducted to investigate nutrient sources and supplementary materials of synthetic compost media for Agaricus bisporus culture. Investigation were carried out to establish the optimum composition for compost of Agaricus bisporus methods of out-door fermentation and peakheating with rice straw as the main substrate of the media. The incidence and flora of harmful organisms in rice straw compost and their control were also studied. 1. When rice straw was used as the main substrate in synthetic compost as a carbon source. yields were remarkably high. Fermentation was more rapid than that of barley straw or wheat straw, and the total nitrogen content was high in rice straw compost. 2. Since the morphological and physico-chemical nature of Japonica and Indica types of rice straw are greatly dissimilar. there were apparent differences in the process of compost fermentation. Fermentation of Indica type straw proceeded more rapidly with a shortening the compost period, reducing the water supply, and required adding of supplementary materials for producing stable physical conditions. 3. Use of barley straw compost resulted in a smaller crop compared with rice straw. but when a 50%, barley straw and 50% rice straw mixture was used, the yield was almost the same as that using only rice straw. 4. There were extremely high positive correlations between yield of Agaricus bisporus and the total nitrogen, organic nitrogen, amino acids, amides and amino sugar nitrogen content of compost. The mycerial growth and fruit body formation were severely inhibited by ammonium nitrogen. 5. When rice straw was used as the main substrate for compost media, urea was the most suitable source of nitrogen. Poor results were obtained with calcium cyanamide and ammonium sulfate. When urea was applied three separate times, nitrogen loss during composting was decreased and the total nitrogen content of compost was increased. 6. The supplementation of organic nutrient activated compost fermentation and increased yield of Agaricus bisporus. The best sources of organic nutrients were: perilla meal, sesame meal, wheat bran and poultry manure, etc. 7. Soybean meal, tobacco powder and glutamic acid fermentation by-products which were industrial wastes, could be substituted for perilla meal, sesame meal and wheat bran as organic nutrient sources for compost media. B. When gypsum and zeolite were added to rice straw. physical deterioration of compost due to excess moisture and caramelization was observed. The Indica type of straw was more remarkable in increase of yield of Agricus bisporus by addition of supplementing materials than Japonica straw. 9. For preparing rice straw compost, the best mixture was prepared by 10% poultry manure, 5% perilla meal, 1. 2 to 1. 5% urea and 1% gypsum. At spring cropping, it was good to add rice bran to accelerate heat generation of the compost heap. 10. There was significantly high positive correlation (r=0.97) between accumulated temperature and the decomposition degree of compost during outdoor composting. The yield was highest at accumulated temperatures between 900 and $1,000^{\circ}C$. 11. Prolonging the composting period brought about an increase in decomposition degree and total nitrogen content, but a decrease in ammonium nitrogen. In the spring the suitable period of composting was 20 to 25 days. and about 15 days in autumn. For those periods, the degree of decomposition was 19 to 24%. 12. Compactness of wet compost at filling caused an increase in the residual ammonium nitrogen. methane and organic acid during peak heating. There was negative correlation between methane content and yield (r=0.76)and the same was true between volatile organic acid and yield (r=0.73). 13. In compost with a moisture content range between 69 to 80% at filling. the higher the moisture content, the lower the yield (r=0.78). This result was attributed to a reduction in the porosity of compost at filling the beds. The optimum porosity for good fermentation was between 41 and 53%. 14. Peak heating of the compost was essential for the prevention of harmful microorganisms and insect pests. and for the removal of excess ammonia. It was necessary to continue fer mentatiion for four days after peak heating. 15. Ten species of fungi which are harmful or competitive to Agaricus bisporus were identified from the rice compost, including Diehliomyces microsporus, Trichoderma sp. and Stysanus stemoites. The frequency of occurrance was notably high with serious damage to Agaricus bisporus. 16. Diehliomyces microsporus could be controlled by temperature adjustment of the growing room and by fumigating the compost and the house with Basamid and Vapam. Trichoderma was prevented by the use of Bavistin and Benomyl. 17. Four species of nematodes and five species of mites occured in compost during out-door composting. These orgnanisms could be controlled through peakheating compost for 6 hours at $60^{\circ}C$.