• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.95-102
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• 2010

In recent years, the demand for the development of high quality and cost effective materials, as well as the competition to ensure a diverse and sufficient amount of ready-mixed concrete, has been increasing rapidly. In this experiment, concretes made with different admixtures are blended with each other in different combinations and ratios, in order to identify potential problems. The first test was a slump level test, in which all of the concretes met the required numbers, as they also did in the test for air content. Plain organic acid concrete scored the highest in bleeding amount, but organic acid mix in general showed a similar outcome. In the early measurement of compressive strength, plain naphthalene concrete was the strongest. Of the blends, the 5:5 mix of organic acid and naphthalene was the strongest. In the standard measurement, the 5:5 mix of naphthalene and lignin was the strongest. Tensile strength tests revealed similar results. Length change rate proved to be greater in blended concrete than in plain concrete, and dry shrinkage rate was highest in the 7:3 ratio blends. Through SEM photo analysis, it was confirmed that the 7:3 ratio blends contained more micro-voids. In conclusion, with the exception of a specific few combinations, it was found that the blending of different types of concrete is undesirable due to the delayed coagulation time as well as the early decrease in strength.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.2
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• pp.84-95
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• 2014

Recently, as a variety of techniques of CMF (Compressed media filter) that has advantages of high porosity and compressibility have been developed in the U.S. and Japan. Therefore, the interest of intensive wastewater treatment using CMF has grown. This study examined the feasibility of CMF with varying sewage water quality to determine the optimum operating conditions. A preliminary tracer test that investigated the filtering process under various compression and flow rate conditions was performed. In a high compression condition, different porosities were applied to each depth of the column. Therefore, a distinct difference between a theoretical value and results of tracer test was observed. For the TSS (Total suspended solid) removal and particle size distribution of CMF for pre-treatment water under the various compression conditions, the compression ratio of 30 percent as the optimal condition showed greater than 70% removal efficiency. In addition, the compression ratio of >15% was required to remove small-sized particles. Also, an additional process such as coagulation is necessary to increase the removal efficiency for < $10{\mu}m$ particles, since these small particles significantly influence the effluent concentration. Modeling results showed that as the compression rate was increased, TSS removal efficiency in accordance with each particle size in the initial filtration was noticeably observed. The modeling results according to the depth of column targeting $10{\mu}m$ particles having the largest percentage in particle size distribution showed that 150-300 mm in filter media layer was the most active with respect to the filtering.

• Journal of Chest Surgery
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• v.13 no.1
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• pp.13-20
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• 1980

Heparin would have been used for preventing clotting of blood during extracorporeal circulation and subsequent use of protamine sulfate and made possible the neutralization of heparin. This procedure has been adopted for eliminating one of the great causes of bleeding, especially in cardiac surgery. In this experiment, the hypocoagulability of blood induced by heparin followed by neutralization with treatment of protamine sulfate were estimated by the Lee-White clotting time [CT], partial thromboplastin time [PTT] and protamine titration test. The results were as follows: 1] Comparison of clotting time between the heparinized [2.0 mg/kg] and non-heparinized dogs was done using CT and PT`I` of the blood. In heparinized group [Group I], the CT lasted infinitively and prolongation of PTT [4 times than normal] until 60 minutes. The CT [2 times] and PTT [3 times] has been shortened after 90 minutes, however they returned to normal limit level within 180 minutes. 2] The determination of appropriate ratio of heparin and protamine In vivo were performed. The group II [heparin 2.0 mg/kg, protamine 1.0 mg/kg] revealed rapid decrease of CT and PTT, but returned to normal after 120 minutes. The group III [heparin 2.0 mg/kg, protamine 2.0 mg/kg] returned rapidly to normal within 15 minutes. The group IV [heparin 2.0 mg/kg, protamine 3.0 mg/kg] recovered its normal level after 60 minutes. The group V [heparin 2.0 mg/kg, protamine 4.0 mg/kg] recovered its normal level after 90 minutes. 3] In the combined experimental study In vivo and vitro, the protamine titration test was done using the dog which were given 2.0 mg/kg and 3.0 mg/kg of heparin, respectively and coagulation time were checked after 15, 30, 60 and 120 minutes. The complete neutralization was showed to be heparin-protamine ratio of 1:1 to 1.5. 4] In vitro study, fresh blood was drawn into known amount of heparin content [20, 40, 60 and 100/ug per 1 ml of blood] syringe, thereafter protamine titration test was done. In all cases, the complete neutralization was found in heparin-protamine ratio of 1:0.85 to 1.5. 5] It was found by the present experiment that the ideal heparin-protamine ratio was 1:1 within 60 minutes and 1:0.5 after 60 minutes for avoiding the serious side effect due to overadministration of protamine sulfate.

• Journal of the Korean Institute of Gas
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• v.21 no.1
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• pp.6-17
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• 2017

Objectives : The purpose of this study was to obtain information regarding Globally Harmonized System(GHS) classification and health hazards that may result from a 4 weeks inhalation exposure of 3-Methylpentane in Sprague-Dawley rats. Methods : The testing method was conducted in accordance with OECD guidelines for the testing of chemicals No. 412(Subacute Inhalation Toxicity). The Rats were divided into 4 groups(5 male and 5 female rats in each group) and exposed to 0 ppm, 284 ppm, 1,135 ppm, 4,540 ppm 3-Methylpentane in each exposure chamber for 6 h/day, 5 days/week, for 4 weeks. After two weeks, the test animals were autopsied and carried out blood test and biochemical tests and histopathological examination. We used PRISTIMA (Toxicology data management system) to confirm the system and to have confidence of the raw data. Results : No death and particular clinical presentation including weight change and change of feed rate was observed. Relationship between dose, gender and response was also not significantly changed in hematologic examination, biochemical examination of blood and blood coagulation time. The histopathologic lesions caused by the test substance did not appear. Conclusions : NOAEL(No Observable Adverse Effect Level) of 3-Methylpentane is more than 4,540 ppm in male group and female group and the Ministry of Employment and Labor Guidance Announcement No. 2013-37(criteria for the classification marks and Safety of Chemicals) Specific target organ toxicity(repeated exposure) was determined with a substance that is not the separator material.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.340-346
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• 1996

In order to find out if staphylococci occur in significant numbers in Korean fermented fish products, a total of 40 different fermented fish products were collected from different markets in Korea and analyzed for their physico-chemical and microbiological states. The pH, salt concentration and water activity of the products were measured and the total viable cell count and the number of Staphylococcus grown on mannitol salt agar were determined. The identification of the strains of Staphylococcus were made by API Staph Strip and MIS identification kits, and the physiological properties of the identified strains were further characterized by different conventional methods. The pH, salt content and water activity of fermented fish samples varied widely from 4.8 to 7.1, 7.4-28.7$%$ and 0.77-0.84, repectively, depending on the type of product. The total viable cell count varied from $10^4-10^9$ cfu/ml, and most of the samples had $10^5-10^6$ cfu/ml No correlation was found between the viable cell count and the pH, NaCl concentration and water activity of the samples. Among the 35 colonies identified as Staphylococcus strains by the identification kits, S. xylosus was the most frequently occurring strain marking 17, and S. warneri was 8, S. epidermidis 4 and S. cohnii 2. S. hominis, S. saprophyticus, S. haemolyticus and S. aureus were also identified once each. In some samples (K-3, P-6, K-8, G-5 and G-10), 2-3 different species of Staphylococcus were found. Considering the region of sampling, among the 10 samples from Kunsan 5 were identified as S. warneri, while in the other regions S. xylosus was predominant. Although the physiological characteristics of the identified strains were generally consistent with those in Bergey's Manual, some discrepances were also observed. All the strains were highly salt tolerant, growing in the media containing over 18$%$ NaCl. All the strains except S. aureus (G-11) showed negative in hemolysis activity, plasma coagulation and DNase tests. All the strains including S. aureus (G-11) showed negative in enterotoxin test.

• Korean Journal of Food Science and Technology
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• v.15 no.2
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• pp.123-127
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• 1983

This experiment was carried out to investigate the change in protein of pasteurized whole egg with or without added 1% of sugar during fermentation S. lactis, L. casei and S. faecalis were used in this fermentation test. Whole egg showed no phenomenen of coagulation by heating at $58^{\circ}C$ for 30 min, but the patterns in polyacrylamide gel of pasteurized whole egg without sugar added were changed by fermentation, especially in the egg fermented with L. casei. Polyacrylamide gel electrophoretic patterns of pasteurized whole egg added 1% of sugar changed more significantly by fermentation than pasteurized whole egg without sugar added and the most significant change was observed in the bands of conalbumin, preconalbumin, globulin and postalbumin by S. faecalis.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.289-296
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• 2010

The purpose of this study is to evaluate various pre-treatment methods and proprieties of water quality for wastewater reuse using reverse osmosis (RO) processes. Secondary effluents were sampled from wastewater treatment plants and lab scale pre-treatments and RO filtration test were conducted systematically. Specifically, different types of pre-treatments, such as coagulation, microfiltration and ultrafiltration, were employed to evaluate the removal efficiency of particle and organic matters which may affect the membrane fouling rate. RO process was later added to eliminate trace amounts of remaining organic matters and salt from the raw water for wastewater reclamation. The permeate through the RO process satisfied water quality regulations for industrial water uses. The experimental results showed that the initial fouling tendency differed not only by the feed water properties but also by the membrane characteristics. Membrane fouling was greater for the membranes with large surface roughness, regardless of the hydrophobicity and zeta potentials. Thus both careful consideration of pre-treatment options and proper selection of RO membrane are of paramount importance for an efficient operation of wastewater treatment.

• Advances in environmental research
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• v.2 no.3
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• pp.229-243
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• 2013

Coagulation-flocculation (CF) was tested coupled with an aerobic biofilter to reduce total petroleum hydrocarbon (TPHs) concentration and toxicity from petrochemical wastewater. The efficiency of the process was followed using turbidity and chemical oxygen demand (COD). The biofilter was packed with a basaltic waste (tezontle) and inoculated with a bacterial consortium. Toxicity test were carried out using Lactuca sativa var. capitata seeds. Best results for turbidity removal were obtained using alum. Considerable turbidity removal was obtained when using Opuntia spp. COD removal with alum was 25%, for Opuntia powder it was 36%. The application of the biofilter allowed the removal of 70% of the remaining TPHs after 30 days with a biodegradation rate (BDR) value 47 $mgL^{-1}d^{-1}$. COD removal was slightly higher with BDR value 63 $mgL^{-1}d^{-1}$. TPH kinetics allowed a degradation rate constant equal to $4.05{\times}10^{-2}d^{-1}$. COD removal showed similar trend with $k=4.23{\times}10^{-2}d^{-1}$. Toxicity reduction was also successfully achieved by the combined treatment process.

• Korean Journal of Veterinary Research
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• v.43 no.2
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• pp.195-202
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• 2003

Chitosan is known to have antibacterial, antitumorogenic, hypolipidemic and immunopotentiating activities, hence finding diverse uses as a component in varying functional foodstuffs. However, some investigators reported it caused mineral absoiption inhibition and excess coagulation. From the chemical viewpoint, conventional chitosans are high-molecule polymers lacking water solubility, which could be related with their possible toxicity. A newly developed low- molecule water soluble chitosan is thought to have low toxicity compared to conventional chitosans. But no investigation was carried out to evaluate its toxicity. In this study, a 28-day subacute oral toxicity study of the water-soluble chitosan was performed in Sprague-Dawley rats of both sexes. Each 36 male and female rats were orally administered with 500, 1,000 and 2,000 mg/kg/day for 28 consecutive days, respectively. Clinical parameters (growth rate, feed and water consumption, daily inspection, urine analysis) during the 28 days indicated the water-soluble chitosan did not induce any abnonnal changes. There were no abnormal findings due to the administration of the test substance in gross and microscopic findings. We had not found alteration in absolute and relative organ weight between the control and treated groups, with only exception in the liver but lacking dose-dependency. The results of hematology and serum biochemistry examination revealed that no treatment related changes were between control and all dose groups. In conclusion, it was suggested that subacute toxicity of the water-soluble chitosan was low and the no-observed adverse effect level was considered to be over 2,000 mg/kg in rats.

• Journal of the Korean GEO-environmental Society
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• v.3 no.4
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• pp.67-79
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• 2002

The purpose of this study is to present criteria of selection of optimum grout materials through analyzing the limitation of permeability of each materials(MSG-N, OPC), in various ground conditions by comparing presentation of strength and permeability of MSG method and LW method(or SGR method). To do that, physical and chemical characteristics of grout materials were analyzed and compressive tests of homogel, mixed coagulation materials and hardening materials in certain mixing ratio, and of milk paste. In addition, permeability tests for each ground soil, each injection pressure, and each materials in combined stratum were performed with massive chamber. The results of tests showed that ultra fine grout materials like grout of MSG is necessary to construct effective grouting in sand and silty sand ground. Also, it is expected to become chemical grouting guide data to layout construction engineers because presented proper injection pressure by kind of object ground in case using ultra-fine grout material.