• Membrane Journal
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• v.21 no.2
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• pp.127-140
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• 2011

The effects of $TiO_2$ photocatalyst coating bead concentration, water-back-flushing period (FT), and back-flushing time (BT) were investigated in hybrid process of ceramic ultrafiltration and photocatalyst for advanced drinking water treatment in this study. Photocatalyst coating bead concentration was changed in the range of 10~40 g/L, FT in 2~10 min and BT in 6~30 sec. Then, we observed the effects on resistance of membrane fouling $(R_f)$, permeate flux (J) and total permeate volume $(V_{\Upsilon})$ during total filtration time of 180 min. As decreasing photocatalyst coating bead concentration, $R_f$ increased and J decreased. $V_{\Upsilon}$ was the highest value of 8.85 L at 40 g/L of photocatalyst coating bead concentration. At FT change experiment, $R_f$ decreased and J increased as decreasing FT. Then $R_f$ decreased and J increased according to increasing BT at BT change experiment. Because at NBF (no back-flushing) dramatic membrane fouling reduced membrane pore size, turbid and dissolved organic matters ($UV_{254}$ absorbance) could be removed efficiently. Therefore, treatment efficiencies of turbidity and dissolved organic matters were the highest at NBF. Then by cleaning effect of photocatalyst coating bead, the treatment efficiencies of turbidity and dissolved organic matters increased as decreasing FT and increasing BT.

• Membrane Journal
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• v.21 no.2
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• pp.201-211
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• 2011

The effects of humic acid (HA), photo-oxidation and adsorption were investigated in hybrid process of ceramic ultrafiltration and photocatalyst for drinking water treatment. UF, photocatalyst, and UV radiation processes were investigated in viewpoints of membrane fouling resistance $(R_f)$, permeate flux (J), and total penneate volume $(V_{\Upsilon})$ at 2 and 4 mg/L of HA respectively. As decreasing HA, $R_f$ decreased dramatically and J increased, and finally $V_{\Upsilon}$ was the highest at 2 mg/L HA. Average treatment efficiencies of turbidity decreased as increasing HA, but treatment efficiency of HA was the highest at 4 mg/L HA. It was because most of HA was removed by membrane and some HA passing through the membrane was adsorbed or photo-oxidized by photocatalyst at low HA, and therefore treated water quality was almost same at 2 and 4 mg/L HA, but feed water quality was higher at 4 mg/L. At effect experiment of photo-oxidation and adsorption, J of UF + $TiO_2$ + UV process was maintained at the highest, and ultimately $(V_{\Upsilon})$ after 180 minutes' operation was the highest. As results of comparing the treatment efficiencies of turbidity and HA, photocatalyst adsorption had more important role than photo-oxidation when HA increased from 2 to 4 mg/L.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.47-51
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• 2001

There are two strategies to cope with the troubles in landfill site after closure. The first method is active in a way that the wastes are dug up and the recyclable materials are reutilized, meanwhile the materials not recyclable are incinerated in order to minimize the volume of residues to be disposed of. The second method is rather passive and defensive in a way that the source of contamination, that is, buried wastes are not treated. Instead, the transport of leaking leachate and gases generated from the wastes are intercepted and controlled. In this study, as a passive way of the efficient leachate blocking process, applicabilities of geocrete and soluble sodium silicate as a substitute to control leachate leaking from landfill sidewall were investigated. In case of compression test, the strength of mixture I (Geocrete:Sodium silicate=1:3.9 v/v) and mixture II (Geocrete:Sodium silicate=1:2.5 v/v), even after 7 days' curing was higher than the minimum allowance to tolerate the loading(5 kg/$\textrm{cm}^2$). Soaking in the acid fur 4 days and 7 days respectively, the compressive strength of the specimens reduced seriously. The toxicity of geocrete is not detected through the bioassay test, once it was mixed with sodium silicate and the complex was formed. The hydraulic conductivity of the mixtures even after 7 days' curing was lower than the threshold limit $(1.0\times10_{-7}cm/s)$.

• Atmosphere
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• v.29 no.4
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• pp.403-416
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• 2019

Precipitation samples were collected at the GAW Stations in Anmyeon-do and Gosan for 10 years (2008-2017) to analyze pH, electrical conductivity and NH₄⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, SO₄^2-, NO₃^-, Cl^-, and F^- ions. From the analysis, the correlation between pH and rainfall, the composition of precipitation and comparison with other regions, and the results of neutralization characteristics by seasonal and pH were determined. In the comparison of ion balance and conductivity for the validation of analytical data, the correlation coefficients were within the range of 0.996~0.999, implying good linear relationship. The volume-weighted pH of the Anmyeon-do and Gosan areas were 4.7 and 4.9, respectively. The pH of the rainfall was affected by washout and rainout in both areas. The ionic strength of precipitation at Anmyeondo and Gosan were 0.42 ± 0.63 mM and 0.37 ± 0.75 mM, indicating about 27.6% and 35.3% of the total precipitation as per a pure precipitation criterion (10^-4 M), respectively. The composition ratio of ionic species were 44.7% and 57.5% for marine sources (Na⁺, Mg²⁺, Cl^-), 40.6% and 22.2% for the secondary inorganic components (NH₄⁺, nss-SO₄^2-, NO₃^-), and 5.6% and 4.0% for the soil source (nss-Ca²⁺), respectively. The neutralization factor of Anmyeon-do and Gosan were 0.43~0.65 and 0.34~0.48, and the neutralization factors of calcium carbonate were 0.15~0.34 and 0.25~0.30, respectively. Thus, both regions have the highest rate of neutralization caused by ammonia. As pH increased in Anmyeon-do and Gosan, change in calcium carbonate became greater than that in ammonia.

• Progress in Medical Physics
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• v.23 no.3
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• pp.127-137
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• 2012

A conversing beam is firstly designed for radiosurgery by a neurosugern Lars Leksell in 1949 with orthogonal x-rays tube moving through horizontal moving arc to focusing the beam at target center. After 2 decades he composits 201 source of the Co-60 for gamma knife which beams focused at locus. Sveral linac-based stereotactic radiosurgery using the circular collimated beam which size range for 0.4~4.0 cm in a diameter by non-coplanar multiarc have been developed over the decades. The irregular lesions can be treated by superimposing with several spherical shots of radiation over the tumour volume. Linac based techniques include the use of between 4 and 11 non-co-planar arcs and a dynamic rotation technique and use photon beam energies in the range of 6~10 MV. Reviews of the characteristics of several treatment techniques can be found in the literature (Podgorsak 1989, Schell 1991). More in recent, static conformal beams defined by custom shaped collimators or a mini- or micro-multileaf collimator (mMLC) have been used in SRS. Finally, in the last few years, intensity-modulated mMLC SRS has also been introduced. Today, many commercial and in-house SRS programs have also introduced non-invasive immobilization systems include the cyberknife and tomotherapy and proton beam. This document will be compared the characteristics of dose distribution of radiosurgery as introduced gamma knife, BrainLab include photon knife in-house SRS program and cyberknife in currently wide used for a cranial SRS.

• Analytical Science and Technology
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• v.18 no.1
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• pp.59-65
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• 2005

When the low level radioactivity sample is measured, it is required to have many samples. For increase of the sample volume, a scattering and absorbing probability of the emitted gamma-ray in the sample are to be increased. In order to correct the self-absorption effect, the counting efficiency must be calibrated according to a geometrical condition and sample density. But, it is impossible to determine efficiency for counting sample using standard source with the same geometrical condition and density. In this study, the measuring efficiencies were determined with various counting containers and densities. In order to compare the self-absorption effect with the sample density in the various sample container, the variation of the counting efficiency with the densities was investigated by adding NaI, which has high solubility and density. Also, they were compared with Monte Carlo simulation. The self-absorption effect was found to be significant in the low energy region below 0.5 MeV.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.283-288
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• 2007

The effects of Ge-Geol radish powder on the physical and sensory properties of wet noodles were investigated by adding 4-16% Ge-Geol radish powder based on the flour source. The Ge-Geol radish powder additions significantly increased the redness of the uncooked and cooked noodles. For the texture profile analysis (TPA) of the wet noodles with added Ge-Geol radish powder, hardness, adhesiveness and resilience decreased, whereas chewiness increased. Changes in the volume and weight of the cooked noodles were not significantly different according to Ge-Geol radish powder concentration, but the turbidities of the soup increased. In sensory test, overall acceptability was significantly higher for the noodles with added Ge-Geol radish powder of concentrations between 4-8%. These samples had similar sensory texture properties as the control and had peculiar hot and cool tastes of the radish. Therefore, adding Ge-Geol radish powder at concentrations below 8% was good for making noodles that maintained a natural texture, and also gave an characteristic radish-like flavor to the noodles.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1353-1359
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• 2007

Water quality constituents, and particle size distributions were characterized in urban bridge road runoff, Bridge road runoff contains significant loads of micro-particles, heavy metals and organic constituents. Bridge road runoff was monitored on four sites of four and six lanes bridge road areas along with traffic volume. A total seven storm events were monitored to characterize the bridge road runoff. The quantity of road runoff and quality constituents, including chemical oxygen demand(COD), suspended solids(SS), total nitrogen(T-N), ortho-phosphorus$(PO_4-P)$, total phosphorus(T-P), and particle size distribution were analyzed. The results indicate that the concentrations of SS, COD, T-N and T-P ranges were $35\sim2,390$ mg/L, $40\sim1,274$ mg/L, $0.03\sim21.25$ mg/L, and $0.05\sim4.58$ mg/L, respectively. And the results showed that the mean range of particle size and $D_{90}$ for bridge road runoff were $4.75\sim14.05{\mu}m$ and $17.33\sim58.15{\mu}m$, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.6
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• pp.818-822
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• 2003

In order to investigate the effect of different sources of energy on intake and nutrient utilization from urea molasses mineral block (UMMB), rumen fermentation pattern and blood biochemical constituents, 18 intact and 9 rumen fistulated male Murrah buffaloes aged about 3 years and average weight 310.8 kg were randomly allocated into three groups of 9 animals in each, thus each group having 6 intact and three rumen fistulated buffaloes. All animals were fed individually for 90 days. All buffaloes were offered wheat straw as basal roughage and urea molasses mineral block for free choice of licking. Three different energy sources viz., barley grain, (group I), maize grain (group II) and jowar green (group III) were offered to meet their nutrient requirement as per Kearl (1982). At the end of feeding trial, a metabolism trial of 7 days duration was carried out on intact animals to determine the digestibility of nutrients. Rumen fermentation studies were carried out on rumen fistulated animals. After the metabolism trial blood was collected from intact animals to estimate the nitrogen constituents in blood serum of animals fed on different sources of energy. Results revealed no significant difference in the intake of UMMB in three groups. Similarly, the intake of DM (kg), DCP (g) and TDN (kg) per day was similar in three groups statistically. The apparent digestibility of dry matter (DM), organic matter (OM), ether extract (EE) and nitrogen free extract (NFE) was significantly (p<0.05) more in group II than group III, whereas the digestibility of DM, OM and NFE was similar in group I and II. The digestibility of crude fiber (CF) and all the fiber fractions i.e. NDF, ADF, cellulose and hemicellulose was alike in 3 groups. Nitrogen balance (g/d) was significantly (p<0.05) more in group III as compared to group I and II, which were alike statistically, though the N intake (g/d) was similar in 3 groups but N balance (g/d) was significantly (p<0.05) less in group III as compared to other 2 groups. Significantly (p<0.05) higher concentration of total volatile fatty acids (TVFA), total nitrogen (TN) and its fractions were observed in group I and II as compared to group III. There was no effect on rumen pH, rumen volume and digesta flow rate due to different sources of energy in 3 groups. Similarly the blood serum biochemical parameters (NH3-N, urea-N and total protein) were statistically identical in 3 groups.

• Environmental Analysis Health and Toxicology
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• v.28
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• pp.7.1-7.9
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• 2013

Objectives We investigated the particle mass size distribution and chemical properties of air pollution particulate matter (PM) in the urban area and its capacity to induce cytotoxicity in human bronchial epithelial (BEAS-2B) cells. Methods To characterize the mass size distributions and chemical concentrations associated with urban PM, PM samples were collected by a 10-stage Micro-Orifice Uniform Deposit Impactor close to nearby traffic in an urban area from December 2007 to December 2009. PM samples for in vitro cytotoxicity testing were collected by a mini-volume air sampler with $PM_{10}$ and $PM_{2.5}$ inlets. Results The PM size distributions were bi-modal, peaking at 0.18 to 0.32 and 1.8 to $3.2{\mu}m$. The mass concentrations of the metals in fine particles (0.1 to $1.8{\mu}m$) accounted for 45.6 to 80.4% of the mass concentrations of metals in $PM_{10}$. The mass proportions of fine particles of the pollutants related to traffic emission, lead (80.4%), cadmium (69.0%), and chromium (63.8%) were higher than those of other metals. Iron was the dominant transition metal in the particles, accounting for 64.3% of the $PM_{10}$ mass in all the samples. We observed PM concentration-dependent cytotoxic effects on BEAS-2B cells. Conclusions We found that exposure to $PM_{2.5}$ and $PM_{10}$ from a nearby traffic area induced significant increases in protein expression of inflammatory cytokines (IL-6 and IL-8). The cell death rate and release of cytokines in response to the $PM_{2.5}$ treatment were higher than those with $PM_{10}$. The combined results support the hypothesis that ultrafine particles from vehicular sources can induce inflammatory responses related to environmental respiratory injury.