• Journal of Advanced Marine Engineering and Technology
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• v.9 no.4
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• pp.339-347
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• 1985

Precise measurement of flowrate is considered as an important measuring factor in mechanical and chemical experiment. Although there are many methods to measure flowrate, Float type flowmeter is widely used because of its easy attachment to piping and high measuring precision. To design the precise float type flowmeter, much design information such as tapered-tube dimensions, float size, float shape and float material is required. In this paper, fundamental design theory for float type flowmeter according to the given flowrate range is suggested and compensation coefficients of volumetric and weight flowrate for water, R-113 and air are calculated.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.117-120
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• 2004

The separation characteristics were investigated with the variations of pressure and temperature using ultrafiltration and reverse osmosis membrane module sets composed of different membrane types and materials. TDS, T-N and COD removal efficiencies were not affected and low with the change of temperature and pressure in case of using UF modules contained in module set 1, 2, 3. TDS, T-N and COD removal efficiencies were very high in RO modules. The final water quality of acrylic wastewater was satisfied within the discharge limit value of plant wastewater. It was known that membrane module sets could be used for the reuse of wastewater.

• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.442-449
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• 2016

The goal of this study is to provide basic data to establish a foundation for the provision of safe drinkable water. The raw water of natural mineral water was analyzed to determine the quantities of anions (F^-, Cl^-, NO_3-N^-, and SO₄^2- ) and cations (Ca²⁺, K⁺, Mg²⁺, and Na⁺) during the former and latter half of 2016. Analysis of the current quality of the raw water of natural mineral water among domestic manufacturers showed average anions contents of 0.46mg/L of fluorine, 8mg/L of chlorine ion, 1.5mg/L of nitrate nitrogen, and 12mg/L of sulfate ion. While the fluorine content was greater than the water quality criterion of 2.0mg/L at four points, the fluorine level was overall stable. The average cations contents included 21.3mg/L of calcium, 1.0mg/L of potassium, 3.4mg/L of magnesium, and 9.6mg/L of sodium. The chemical characteristics were compared among the major ions, and the results are presented in a piper diagram. The content ratio of cations was in the order of Ca²⁺> Na⁺>Mg²⁺>K⁺, whereas that of anions was in the order of SO₄^2->Cl^->NO_3-N^->F^-. While the cations were slightly scattered, the anions were generally concentrated except for at a few points. The Ca-Na-HCO₃ type was dominant overall in water sources from diorite, gneiss, and granite, while the Na-Mg-Ca-HCO₃-Cl type was dominant in basalt sources. Mineral water manufacturers source their water under various conditions, including in-hole casing, excavation depth, and contact state of bedrock; even within the same rocky area, some differences in the water quality type can occur. When the depth of the water source was taken into account, the mean anions contents of F^-, Cl^-, NO_3-N^-, and SO₄^2- were similar, with no significant differences according to depth. Of the cations, K⁺ and Na⁺ showed no significant differences across all the tubular wells, whereas Ca²⁺ and Mg²⁺ decreased in content with depth.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2753-2759
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• 2013

The aim of the present study is to explore the possibility of utilizing fly ash and loess, as alternative to activated carbon, for the adsorption of diazinon in water. Batch adsorption experiment was performed to evaluate the influences of various factors like initial concentration, contact time and temperature on the adsorption of diazinon. The adsorption data shows that fly ash is not effective for the adsorption of diazinon. The equilibrium data for both activated carbon and loess were fitted well to the Freundlich isotherm model. The pseudo-second-order kinetic model appeared to be the better-fitting model because it has higher $R^2$ compared to the pseudo-first-order kinetic model. The thermodynamic parameters such as free energy (${\Delta}G$), the enthalpy (${\Delta}H$) and the entropy (${\Delta}S$) were calculated. Contrary to loess, the ${\Delta}G$ values of activated carbon were negative at the studied temperatures. It indicates that the adsorption of diazinon by activated carbon is a favorable and spontaneous process. The positive ${\Delta}H$ values of activated carbon and loess suggest that the diazinon adsorption process is endothermic in nature. In addition, the positive ${\Delta}S$ values show that increased randomness occurs at the solid/solution surface during the adsorption of diazinon.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.878-887
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• 2020

A neutral extract (NE), that is soluble in cold water and has excellent antioxidant activity, from Pinus radiata pine bark was prepared by sodium bicarbonate treatment, and its chemical characteristics were investigated. NE was prepared by treating P. radiata bark with 0.8% NaHCO₃ aqueous solution with a 5 : 1 liquor-to-bark ratio at boiling temperature for 1 h, resulting in 44% yield and final pH of 6.66. The yield of NE was 11% higher than that of the hot water extract (HWE) due to the increase in the solubility of polyphenols, the main component in the bark, by NaHCO₃ treatment. NE was characterized through FT-IR, NMR, and MALDI TOF MS analyses. The results indicated that NE is mostly composed of proanthocyanidins (PAs) consisting of procyanidin (PC) units. The acetylated neutral extract (Ac-NE) had weight average molecular weight (${\bar{M}}w$) of 5,300 Da. The Ac-NE had wide molecular weight distribution and its polydispersity (${\bar{M}}w/{\bar{M}}n$) was 6 times higher than that of pure PA. The antioxidant activity of NE was determined by 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and showed that NE had comparable antioxidant activity with pure PA.

• Food Science of Animal Resources
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• v.20 no.3
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• pp.236-241
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• 2000

본 연구는 한우우소뼈로 만든 용출액의 품질에 대한 과학적인 자료를 제시하고 한우뼈의 부가가치 향상 및 소비 확대를 위하여 추출횟수별에 따른 이화학적, 관능적 및 영양적 특성을 규명하였다. 탁도, 점도 및 콘드리이친황산함량에서 추출횟수가 증가할수록 유의적으로 감소한 반면(P<0.05), 콜라겐 함량에서는 추출회수가 증가할수록 유의적으로 증가하였다(P<0.05). 색도에서 명도는 추출회수가 증가할수록 유의적으로 감소한 반면, 적색도와황색도는 증가하였다(P<0.05) 관능평가에서 추출 회수가 증가할수록 평가가 유의적으로 낮았고 (P<0.05), 총질소, 나트륨, 칼슘 함량 및 칼로리는 추출회수가 증가할수록 2차추출까지 증가하다가 이후 유의적으로 감소하였다. (P<0.05)조직특성에서 추출전 대퇴골의 단면은 골수가 많이 분포하고 있으나 추출회수가 증가할수록 골수가 추출되어 3차 추출이후의 대퇴골 단면에는 골수 성분이 거의 나타나지 않았다. 이상의결과를 종합하여 볼 때 한우우소뼈로 설렁탕을 가정에서 제조시 3차까지 우려내는 것이 적당한 것으로 사료된다.

• Journal of the Korean Chemical Society
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• v.6 no.2
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• pp.117-121
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• 1962

The waters throughout Taegu area for 87 points were analysed and according to the analytical data, following unfavorable characteristics for industrial uses were given: (1)Shows strong hardness, (2)Has high ratio of ignition residue to evaporation residue, (3) pH value is over 7, (4) Contains considerable quntities of iron.And then investigated the exchange rate and regeneration level of iron ion using cation exchange resin, Lewatit KS.When the hard water containing 2.2 ppm of iron with 18.4 ppm of calcium and 6.2 ppm of magnesium was passed through the ion exchange resin under $3cc/cm^2/min$ in exhaustant flow rate, exchange rate of iron reached to 42% after 300 hours flow. The exchange efficiency shows abrupt decreasing in initial stage of flow up to 100 hours flow. The exchanger which contains iron was regenerated with 10% sodium hydroxide aqua solution under SV (space velocity) 4. By this method, 57% of iron was eliminated from exchanger while calcium and magnesium are removed as much as 85% and 87% respectively.

• Membrane and Water Treatment
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• v.4 no.2
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• pp.109-126
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• 2013

Surface modification by low-pressure ammonia ($NH_3$) plasma on commercial thin-film composite (TFC) membranes was investigated in this study. Surface hydrophilicity, total surface free energy, ion exchange capacity (IEC) and zeta (${\zeta}$)-potentials were determined for the TFC membranes. Qualitative and quantitative analyses of the membrane surface chemistry were conducted by attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy. Results showed that the $NH_3$ plasma treatment increased the surface hydrophilicity, in particular at a plasma treatment time longer than 5 min at 50 W of plasma power. Total surface free energy was influenced by the basic polar components introduced by the $NH_3$ plasma, and isoelectric point (IEP) was shifted to higher pH region after the modification. A ten (10) min $NH_3$ plasma treatment at 90 W was found to be adequate for the TFC membrane modification, resulting in a membrane with better characteristics than the TFC membranes without the modification for water treatment. The thin-film chemistry (i.e., fully-aromatic and semi-aromatic nature in the interfacial polymerization) influenced the initial stage of plasma modification.

• Journal of the Korean Chemical Society
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• v.12 no.3
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• pp.99-105
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• 1968

Some ortho-hydroxy monoazo-compounds have been synthesized and these were metallized with transition elements. Chromium trioxide, cupric acetate and cobalt acetate were used for the metallization. The following facts have been found in this investigation: (1) water is the best solvent, when compared to various organic solvents, for the metallization, (2) the optimum pH for the metallizing mixture ranges from 4.5 to 5.5, (3) the solubility of these metallic monoazo-compounds in water depends mainly on the composition of the complexes and to some extent on the presence of sulfonic acid groups in the molecules, and (4) metallized compounds having two ortho-hydroxy groups per molecule have stronger binding characteristics.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.401-408
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• 2012

High-voltage dielectric discharges are an emerging technique in environmental pollutant degradation, which that are characterized by the production of hydroxyl radicals as the primary degradation species. The initiation and propagation of the electrical discharges depends on several physical, chemical, and electrical parameters such as 1st and 2nd voltage of power, gas supply, conductivity and pH. These parameters also influence the physical and chemical characteristics of the discharges, including the production of reactive species such as OH, $H_2O_2$ and $O_3$. The experimental results showed that the optimum 1st voltage and air flow rate for RNO (N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical) degradation were 160 V (2nd voltage of is 15 kV) and 4 L/min, respectively. As the increased of the 2nd voltage (4 kV to 15 kV), RNO degradation, $H_2O_2$ and $O_3$ generation were increased. The conductivity of the solution was not influencing the RNO degradation and $H_2O_2$ and $O_3$ generation. The effects pH was not high on RNO degradation. However, the lower pH and the conductivity, the higher $H_2O_2$ and $O_3$ generation were observed.