• Journal for History of Mathematics
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• v.27 no.2
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• pp.101-110
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• 2014

Joseon is mainly an agricultural country and its main source of national revenue is the farmland tax. Since the beginning of the Joseon dynasty, the assessment and taxation of agricultural land became one of the most important subjects in the national administration. Consequently, the measurement of fields, or the area of various plane figures and curved surfaces is a very much important topic for mathematical officials. Consequently Joseon mathematicians were concerned about the volumes of solids more for those of granaries than those of earthworks. The area and volume together with surveying have been main geometrical subjects in Joseon mathematics as well. In this paper we discuss the history of volumes of solids in Joseon mathematics and the influences of Chinese mathematics on the subject.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.289-296
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• 2017

Pulp and paper industry produces large volumes of wastewater and residual sludge waste, resulting in many issues in relation to wastewater treatment and sludge disposal. Contaminants in pulp and paper wastewater include effluent solids, sediments, chemical oxygen demand (COD), and biological oxygen demand (BOD), which should be treated by wastewater treatment processes such as coagulation and biological treatment. However, few works have been attempted to predict the treatment efficiency of pulp and paper wastewater. Accordingly, this study presented empirical models based on experimental data in laboratory-scale coagulation tests and compared them with statistical models such as artificial neural network (ANN). Results showed that the water quality parameters such as turbidity, suspended solids, COD, and UVA can be predicted using either linear or expoential regression models. Nevertheless, the accuracies for turbidity and UVA predictions were relatively lower than those for SS and COD. On the other hand, ANN showed higher accuracies than the emprical models for all water parameters. However, it seems that two kinds of models should be used together to provide more accurate information on the treatment efficiency of pulp and paper wastewater.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.1
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• pp.69-75
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• 1988

Two rational formulae depicting the relationships between sludge ages and recycle flow rates have been developed to determine sludge wasting volumes at a particular sludge age. A sensitivity analysis shows that the recycle ratio is the most important variable to be measured as accurately as possible in determining the sludge wasting volume to maintain a particular sludge age when the system is controlled by wasting recycled sludge. On the other hand, the final clarifier solids capturing capacity is the most important variable to be measured when the system is operated by wasting mixed liquor.

• Environmental Engineering Research
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• v.14 no.4
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• pp.262-269
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• 2009

This study examined the separation characteristics of particles in the rainfall runoff from paved roads using a ${\varphi}7.5$ cm hydrocyclone. The volume fraction and total suspended solids concentrations in the overflow and underflow from the hydrocyclone, as well as the separation efficiency were determined. The results indicated that the overflow volume increased with increasing operational pressure, but decreased with decreasing ratio of underflow outlet to inlet sizes ($D_u/D_i$), while the underflow to overflow volumes showed contrary behavior. The total suspended solid (TSS) concentration ratio between the overflow and inflow ($TSS_{over/in}$) decreased as a function of the operational pressure, while the corresponding ratio of underflow to inflow ($TSS_{under/in}$) increased. There was no visible difference in the $TSS_{over/in}$ with increasing $D_u/D_i$ ratio, but the $TSS_{under/in}$ decreased sharply. The particle removal efficiency was mainly affected by the particle size.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.314-320
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• 2006

Diffuse pollution from an urban area contributes to the significant pollution loading to a receiving water body. In this paper, rainfall runoffs from an urban basin with combined sewer systems located in the city of Daejeon were monitored to measure the rainfall runoff discharge rates and pollutant concentrations. Strong first flush effects were observed for all monitored rainfall runoffs. The first flush effects were closely related to rainfall intensity, while suspended solids were closely related to pollutant constituents. The observed averaged Event Mean Concentrations (EMCs) of Combined Sewer Overflows (CSOs) were 536.1 mg SS/L, 467.7 mg CODcr/L, 142.7 mg BOD/L, 16.5 mg TN/L, and 13.5 mg TP/L. Storage volumes for containing the first flush to improve water quality of the receiving stream can be estimated based on suspended solid concentration. In this study, retainment of the first flush equivalent to 5mm of precipitation could reduce diffuse pollution loading induced by CSOs to a receiving water body by up to 80% of suspended solid loading.

• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.12-25
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• 2015

The tributaries of Daechung Lake play an important role in controlling eutrophication in the lake, which is used for agricultural purposes and as potable water. However, water quality properties were not extensively studied in the tributaries of Daechung Lake. The objectives of this study are to investigate spatial and temporal properties of water quality and to characterize streams which could threaten water quality of Daechung Lake. For this study, water samples were weekly or monthly collected from February 2014 to October 2014 in 9 streams. Water quality parameters analyzed in this study include biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen and phosphorus (TN and TP), suspended solids (SS), and chlorophyll a. Based on temporal distribution and principal component analysis, BOD, COD, TOC, SS, and TP were controlled by not only river discharge that increased during summer due to heavy rain fall, but also due to anthropogenic input (e.g., bridge construction and/or agricultural activity). Dilution is also one of the factors explaining TN and conductivity, both of which decreased with increased discharge. Generally, concentrations of contaminants (BOD, COD, TOC, TN and TP) in the tributaries were higher than those of Daechung Lake. However, pollution load indicated that only the main channel of Geum River and Sook Stream may largely influence lake waters, attributed mostly to their large volumes. This implies that the main channel and Sook Stream are the major influences on the water quality of Daechung Lake.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.92-97
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• 1997

Beverages using mountain edible herbs(MEH) were formulated by determining optimum ratio of juices of MEH to several other ingredients. Fermented beverages were made by mixing juices(1 volume) fermented with Lactobacillus helverticus with syrup(3 volumes), followed by homogenization and flavoring . The general analysis and quality change of the beverages during storage were Peformed. The analysis of the beverages showed that the pH of Synurus deltoides and Cirsium sctidens were 3.8 and 3.7, titratable acidities were 0.50 and 0.49, optical densities were 1.201 and 1.119, respectively, The pH and color were not significantly changed when Synurus deltoides and Cirsium sctidens were stored at room temperature and 37$^{\circ}C$ for 6 months. The pH of Synurs deltoides beverage ranged 3.95~3.96 and pH of Cirsium sctidens was 3.83~3.95 at room temperature and 3.87~3.98 at 37$^{\circ}C$, respectively. The analysis of fermented beverages showed that pHs of Synurus deltoides and Cirsium sctidens were 3.65 and 3.70, titratable acidities were 0.57 and 0.60. Solids-non-fat were 3.2 and 3.1, and total counts of lactic acid bacteria were 2.5$\times$10$^{8}$ and 4.0$\times$10$^{8}$ , respectively. The changes of pH and titratable acidities stored at 4$^{\circ}C$ for 15 days were 3.39~3.56 and 0.61~0.81 for Synurus deltoides and 3.48~3.67 and 0.60~0.78 for Cirsium sctidens, respectively.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.300-310
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• 2022

The objective of this experiment was to investigate the effect of drip irrigation volume on tomatoes (Solanum lycopersicum L.) grown in a greenhouse using perlite medium. Plants were treated by three different irrigation treatment I₀, I₂₅, and I₅₀ (where irrigation volume of I₂₅ and I₅₀ was 25% and 50% higher than I₀, having limited or no leaching). Growth characteristics of plants, yield and water use efficiency were measured. The result showed that plant height, leaf length and leaf width were lowest in the I₀ treated plants. However, these parameters were not statistically significant differences between the plants that were grown in the I₂₅ and I₅₀ treatment. Soluble solids content, acidity and dry matter of 111th, 132nd, and 143rd days harvested tomato were higher in the plants irrigated with lowest volume (I₀) than the higher volume (I₂₅ or I₅₀). In addition, water content was lower in the 111th and 132nd days of harvested tomatoes from the I₀ treatment. The number of big-size tomatoes (>180 g) was significantly higher in the I₂₅ irrigated plants. There was no significant difference in the total number of harvested fruits among the treatments. The average fruit weight and total yield of harvested tomatoes were lowest in the I₀ treated plants. The water consumption of tomato was not significantly different amongst the treatments but water use efficiency was lowest in the I₀ treatment. Principal component analysis revealed that total soluble solid and acidity of tomato showed a positive correlation between each other. These results suggest that I₂₅ was the optimum irrigation treatment for tomato based on its measured growth characteristics, yield and water use efficiency.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.65-75
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• 1972

The rice qualities including cooking and eating qualities were studied using recommended Korean rice varieties (20 of japonica and 3 of indies type; IR 667) which were grown at Suwon, Korea in 1971. As the result, followings were obtained. 1. Amylose contents of white rice were varied with the varieties 21.1 to 25.5% and the average was 23.0%. Three indica type varieties (IR 667) showed higher amylose contents than the other japonica type varieties except Mankyung. Among japonica type varieties, Palkum, Mankyung composed the group of the highest amyloes content and Kimmaje was the lowest. 2. Blue values were distributed in the range of 0.38 to 0.48 and the average was 0.42 IR 667 varieties showed the highest blue value among them. Among japonica type varieties, Jaegun showd the highest blue value and Sooseung, Shirogane showed successively lower values, Shin #2, Nongbaik, Palkweng, Suwon #82, Mankyung, Nonglim #25 and Nongkwang relatively lower blue values. 3. Alkali numbers were in the range of 6.0 to 7.4 and the average was 6.8. Much difference was not shown in alkali number between IR 667 group and the japonica varieties group. 4. Gelatinization temperature were ranged from 59.5 to 64.0 IR 667 varieties showed relatively higher gelatinization temperature than japonica type varieties. 5. Water uptake ratios were measured in the range of 2.67 to 2.92 and the average was 2.79. IR 667 varieties were belonged to the group of highest water uptake ratio. Among japonica type varieties Kimmaje, Suwon #82, Nonglim #29, Deungpan #5, Jaegun, Jinhung, were belonged to the group of relatively high water uptake ratio and Palkweng, Palkeum and Paldal to the relatively low water uptake ratio. 6. Expaned volums were ranged from 29.8 to 33.7 and the average was 31.8. IR 667 varieties showed higher expanded volumes than japonica type varieties. 7. Intensities of starch-iodine blue value of residual liquid indicated 0.35 to 0.58. Among them IR 667 varieties showed relatively high intensities. 8. The range of total solids in residual liquids was 0.605 to 0.810 and the average was 0.700 Much difference was not shown in total solids in residual liquid between IR 667 varieties and japonica varieties. 9. pH values of residual liquids were in the range of 6.3 to 7.3 and the average was 6.95. IR 667 varieties showed lower pH than japonira type varieties.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.447-453
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• 2019

In this study, the effect of supplying volume and frequency of a nutrient solution consisted with $NO_3-N$ 4.6, $NH_4-N$ 3.4, $PO_4-P$ 3, K 3, Ca 4.6 and Mg $2.2mmol{\cdot}L^{-1}$ on growth and fruit quality of 'Duke' blueberry was investigated. Three years old 'Duke' blueberry bushes cultivated in containers ($60{\times}80{\times}40cm$) filled with 130L peat moss and 40L pearlite (v/v) were selected for the experiment. The growth containers were mulched with sawdust. Two different volumes (4L and 8L) of nutrient solution was tested at three different supplying frequencies (one time, two times, and three times) per week and the drainage quality of nutrient solution and fruit quality of 'Duke' blueberry was evaluated. The optimal drainage rate for the vegetable cultivation is known to be 20-30%. The results revealed that the average drainage rates of 27% and 29% for the nutrient solution supplied in 'Duke' blueberry growth medium at 4L, 2 times/7 days and 4L, 3 times/7days, respectively. The highest shoot diameter (4.2mm) and shoot length (31cm) of 'Duke' blueberry was recorded with the 8L of nutrient solution supplied at 3 times per 7 days. According to the analysis of inorganic components in the drainage of nutrient solution, there was a tendency of absorbing nitrogen at the early stage of growth. The supplying volume and frequency of nutrient solution was not significantly affected on 'Duke' blueberry fruit weight, soluble solids content, and titratable acidity. The highest yield per bush (2.7kg) was recorded for the nutrient solution supplied with 4L at three times per 7 days, while the 4L nutrient solution supplied at one time per 7 days resulted the lowest yield of 1.4kg per bush. Consequently, the tested nutrient solution can be applied for the 'Duke' blueberry bushes with the volume of 4L at three times per week for the better crop growth.