• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.2
• /
• pp.265-272
• /
• 2006

While sludge settles down in a column, sludge settling characteristic is influenced by effect parameters, interparticle force, wall effect etc. As the height of a column changes, the settling velocity of sludge-water interface changes, too. At lower sludge concentration, particular effect was not observed by the difference of column height, however it was observed that settleability of sludge was greatly influenced by column height when sludge settling was poor or sludge concentration was high. It is therefore required to consider the effect of column height when the power model for sludge interface settling is established. In the tests, there was hardly any $SVI_{ts}$(SVI after "t" minutes) difference in each column after 10min at $1.5kg/m^3$ of sludge concentration. When sludge concentration was at $2.5kg/m^3$, $SVI_{ts}$ tended to be constant after 20min. At $3.5kg/m^3$, $SVI_{ts}$ increased to 30minuets. The purpose of this work is to establish the correction factor that is able to compensate the errors derived from each different height of column.

• Korean Journal of Metals and Materials
• /
• v.48 no.2
• /
• pp.148-153
• /
• 2010

The effects of Cu(II) and Al(III) on the extraction and separation of Pt(IV) and Pd(II) have been investigated in a mixed chloride solution using Alamine336 as the extractant. In the HCl concentration range of 1 to 5 M, more than 99% of Pt and Pd could be extracted by Alamine336 from all of the mixed chloride solutions investigated in this study. Lower HCl concentration led to a higher separation factor between Pd and Pt when Alamine336 concentration was constant. Extraction percentage of Cu increased with the increase of HCl concentration, while that of Al was nearly constant at 33% in our experimental range. The optimum conditions to extract Pt and Pd from Cu or Al and the separation factor under these conditions were obtained.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.24 no.2
• /
• pp.137-145
• /
• 2014

Objectives: The study examines the relation between urinary arsenic concentration and blood pressure, which is a risk factor of cardiovascular disease. Materials: In this study, the urinary arsenic concentration, history of diagnosed disease, and blood pressure of 782 local residents in Gwangyang, Yeosu, and Hadong regions from May 2007 to July 2007. Results: The urinary arsenic concentration of total participants was $9.06{\mu}g/g-ct$. The logistic regression analysis of medical diagnosed history and urinary arsenic concentration, showed statistically significance (p<0.05) of high urinary arsenic concentration in participants with diagnosed hypertension. In addition, diagnosed hypertension it was observed that the high blood pressure was related with the pulse pressure. Conclusions: The arsenic concentration level was low in this study, but the exposure to low levels of arsenic has an effect on hypertension. Also, hypertension is related to pulse pressure and mean arterial blood pressure as well as being risk factor of cardiovascular disease. Therefore, close supervision of low -level arsenic exposure is needed.

• Journal of Environmental Health Sciences
• /
• v.20 no.1
• /
• pp.75-82
• /
• 1994

Bioconcentration Factor (BCF) is known as important criteria for ecotoxicology on hazardous chemicals. But there is no standard method for determining BCF and reported BCFs were slightly different in accordance with authors. This study was performed with aims to determine BCFs on BPMC and Carbaryl. Carassius auratus(goldfish) be chosen as test organism and test period were 3-day, 5-day and 10-day. Extract solvents were n-hexane and acetonitrile. GC-ECD was used to detecting carbamates. The obtained results were as follows: 1. It was possible to determine short term BCF$_s$ of Carbaryl or BPMC through relatively simple procedure. 2. BCF$_3$ of Carbaryl in concentration of 1, 2, 5, 10 ppm were 0.34 $\pm$ 0.06, 0.18 $\pm$ 0.02, 0.10 $\pm$ 0.01, 0.06 $\pm$ 0.01 respectively. BCF$_5$ of Carbaryl were 0.34 $\pm$ 0.05, 0.18 $\pm$ 0.02, 0.13 $\pm$ 0.01 and 0.07 $\pm$ 0.01, BCF$_{10}3$ of Carbaryl were 0.45 $\pm$ 0.05, 0.27 $\pm$ 0.02, 0.16 $\pm$ 0.02 and 0.09 $\pm$ 0.01. BCF$_3$ of BPMC in concentration of 1, 2, 5 ppm were 4.66 $\pm$ 0.17, 2.64 $\pm$ 0.49, 1.88 $\pm$ 0.24 respectively. BCF$_5$ of BPMC were 4.09 $\pm$ 0.50, 2.42 $\pm$ 0.37 and 1.83 $\pm$ 0.15. 3. BCF$_s$ of BPMC were decreased as increasing concentration. However, BPMC concentration in fish were increased in contrast to BCF. But more concentrated BPMC was found in fish 3-day test than found concentration in fish 5-day test. 4. Same trend appeared in Carbaryl. BCF$_s$ of Carbaryl were decreased as increasing concentration and prolonging test period. But found Carbaryl concentration in fish were increased. 5. BCF$_s$ of BPMC were higher than that of Carbaryl by 10 times, in spite of the physicochemical properties of the two carbamates were similar to each other. Further study is recommended to find out the reason of the difference.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.20 no.4
• /
• pp.1-13
• /
• 2017

The purpose of this study is to analyze a term of decade of water quality data of the Mulgum intake station on the Nakdong river(dam) to find the cause of algal blooms and to set an alternative to prevent artificial lake water pollution. Our study shows that water quality changes have regular periodic regularity and there was a certain correlation between specific analytical items. According to the analysis results of each factor, the decline in precipitation was not the main reason for algal blooms. TP concentration had a slight effect on Chl-a concentration but was not a limiting nutrient of a bloom. TN concentration had a strong correlation with Chl-a and strongly negative correlation with temperature, but was not a bloom's limiting nutrient, and was only a dependent variable. As the temperature was negatively correlated with the Chl-a concentration, it is found that the aspect of the ecological influence of the temperature was the most important factor of the phytoplankton concentration change. The N/P ratio lies under a power function with a high degree of reliability by the TP concentration, and the phenomenon appeared to be the same as the results of two other comparative areas. This result confirms that TN is dependent on TP and the biota in the lake that TN is a dependent variable whose concentration is determined by TP it. In conclusion, the increase in lake bloom is the result of a food chain change, and it is necessary to control the ecosystem by the food chain in the lake in order to reduce the lake's bloom. In particular, it is important to keep the benthic ecosystem as wide as possible in the aerobic state.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.155-160
• /
• 2004

Permeation experiments of a commercial nanofiltration membrane (nominated as ESNA 1) were carried out with aqueous solutions of various single salts, that is, five chlorides (NH$_4$Cl, NaCl, KCl, MgCl$_2$ and $CaCl_2$), three nitrates $(NaNo_3,\;Mg(No_3)_2\;and\;Ca(NO_3)_2)\;and\;three\;sulfates\;((NH_4)_2SO_4,\;Na_2SO_4\;and\;MgSO_4)$. The experimental results showed that (1) the permeate volume flux of the ESNA 1 membrane increased and decreased with the growth of the applied pressure and the feed concentration of salts, respectively. The real rejection of ESNA 1 membrane to most single salts increased with the growth of the permeate volume flux. (2) The reflection coefficients of ESNA 1 membrane to chlorides, nitrates and sulfates are 0.97, 0.96 and 0.99, respectively. The solute permeability of most salts except for magnesium and calcium salts increased with the growth of feed concentration. (3) The sequence of the rejections of ESNA 1 membrane to anions is $R({SO_4}^{2-})>R(CI)>R(NO_3)$ at the same feed concentration. While the sequence of the rejections to cations is cataloged into two cases: $R(Na^+)>R(K^+)>R(Mg^{2+})>R(Ca^{2+})$ at the concentration of 10 mol/$m^3$ and $R(Mg^{2+})>R(Ca^{2+})>R(Na^+)>R(K^+)$ at the concentration of 100 mol/$m^3$. The separation capability of a NF membrane is usually affected by the electrostatic effect and the steric-hindrance effect. In this case, the electrostatic effect is the major factor at low concentration and the steric-hindrance effect is the major factor at high concentration. Both the specific sorption and the hydration also reasonably influenced the separation performance of NF membrane to salts.

• YAKHAK HOEJI
• /
• v.48 no.1
• /
• pp.6-12
• /
• 2004

Near-infrared spectra of methanol-water mixtures and acetonitrile-water mixtures were acquired to find interactions between solvents widely used for reverse-phase liquid chromatography. Mixtures were prepared to give a series of increasing mole fractions of methanol or acetonitrile in water. Data matrices of acquired spectra were analyzed to determine the proper number of principal components of each mixture system using Malinowski's factor indicator function. Initial guess of score matrix and loading matrix were calculated by nonlinear iterative partial least squares (NIPALS) algorithm for faster computation. Iterative target transform factor analysis (ITTFA) was applied to convert the initial estimation of score matrix to true concentration profile and loading matrix to pure spectra of pure components of the mixtures. In case of methanol-water the number of principal components was found to be 4 and those initial guess of factors were converted to the pure spectra of water methanol and two kinds of complexes. In case of acetonitrile-water the number of pure components of the mixtures was found to be 3 and the pure spectrum of acetonitrile-water complex was found. The nonlinear characteristics of concentration profiles of complexes in the solvent mixtures may give a good criteria in understanding their elution characteristics in reverse-phase liquid chromatogrsphy.

• KSBB Journal
• /
• v.28 no.4
• /
• pp.254-259
• /
• 2013

Herein we present a diagnostic paper chip that can quantitatively detect albumin without external electronic reader and dispensing apparatus. We fabricated a diagnostic paper chip device by printing wax barrier on the paper and wicking it with citrate buffer and tetrabromophenol blue to detect albumin in sample solution. The paper chip is so simple that we dropped a sample solution at sample pad and measure the ratio of two travel distances of the sample solvent and albumin under the name of retention factor. Our result confirmed that the retention factor was constant in the samples with same concentration of albumin and useful determinant for the measurement of albumin concentration. The paper chip is affordable and equipment-free, and close to ideal point-of-care test in accordance with the assured criteria, outlined by the World Health Organization. We assume that this diagnostic paper chip will expand the concept of colorimetric determination and provide a inexpensive diagnostic method to aging society and developing country.

• Journal of Sensor Science and Technology
• /
• v.33 no.1
• /
• pp.1-6
• /
• 2024

This study aims to suggest the partition ratio (Q-factor) of healthy Koreans and the comparison results of breath alcohol concentration (BAC) measurements using two methods (photoacoustic and electrochemical methods) for developing breath alcohol ignition interlock devices (BAIIDs). Given the relationship between BACs and BrACs and the Q-factor, the alcohol metabolism of healthy Koreans (96 males and 91 females) is revealed for understanding the digestion of alcohol and surveying the fundamental data of alcohol-related problems, CO₂ concentrations vs. alcohol concentrations, and the performance of alcohol sensors in the marketplace. The average Q-factor of healthy Korean males and females are 1,913 (95% confidence interval from 1,889-1,937) and 1,991 (95% confidence interval from 1,945-2,036). Photoacoustic measurements could be applied to predict the BACs of drinkers, which is confirmed by the Bland-Altman plots presented in this study. The biases based on the partition ratios (Q=1,913 and Q=1,991) in the Bland-Altman plots were -0.0004% (95% CI from -0.0011 to +0.0003% for males) and -0.0017% (95% CI from -0.020 to +0.017% for females).

• Bulletin of the Korean Chemical Society
• /
• v.27 no.5
• /
• pp.718-724
• /
• 2006

The heterogeneous association behaviour of various concentration binary mixtures of mono alkyl ethers of ethylene glycol with ethyl alcohol were investigated by dielectric measurement in benzene solutions over the entire concentration range at 25 ${^{\circ}C}$. The values of static dielectric constant $\epsilon_0$ of the mixtures were measured at 1 MHz using a four terminal dielectric liquid test fixture and precision LCR meter. The high frequency limiting dielectric constant $\epsilon_\infty$ values were determined by measurement of refractive index $n_D$ ($\epsilon_\infty\;=\;n_D\;^2$). The measured values of $\epsilon_0$ and $\epsilon_\infty$ were used to evaluate the values of excess dielectric constant $\epsilon^E$, effective Kirkwood correlation factor $g^{eff}$ and corrective correlation factor $g_f$ of the binary polar mixtures to obtain qualitative and quantitative information about the H-bond complex formation. The non-linear behaviour of the observed $\epsilon_0$ values of the polar molecules and their mixtures in benzene solvent confirms the variation in the associated structures with change in polar mixture constituents concentration and also by dilution in non-polar solvents. Appearance of the maximum in $\epsilon^E$ values at different concentration of the polar mixtures suggest the formation of stable adduct complex, which depends on the molecular size of the mono alkyl ethers of ethylene glycol. Further, the observed $\epsilon^E$ < 0 also confirms the heterogeneous H-bond complex formation reduces the effective number of dipoles in these polar binary mixtures. In benzene solutions these polar molecules shows the maximum reduce in effective number of dipoles at 50 percent dilutions. But ethyl alcohol rich binary polar mixtures in benzene solvent show the maximum reduce in effective number of dipoles in benzene rich solutions.