• Advances in concrete construction
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• v.10 no.4
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• pp.311-317
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• 2020

Performance of Sustainable materials continues through using of recycled waste construction materials to minimize the utilization of the natural resources. The cement industry is a major source of CO₂ in the atmosphere which is the main cause of global warming. Replacement of OPC with other sustainable cementitious materials has been the most interesting area of researches. This investigation focuses on the properties of alkali-activated mortar with the different replacement ratios of ceramic tile powder (CTP) by fine soil powder (FSP) (0 to 100)% and different molarities of sodium hydroxide concentrations. The experimental program was conducted by examining the compressive strength, water absorption, and water sorptivity. The results showed that the compressive strength of the specimens at age of (28, 56, and 90 days) increases with an increase in the amount of fine soil powder content and decreases at the age of 120 days. Also, minimum water absorption at the age of 90 days was found in the mixes containing 100% fine soil powder. However, fine soil powder replacement had a negative effect on the sorptivity and water absorption values at the age of 120 days. On the other hand, the 12M sodium hydroxide concentration was considered the optimum concentration compared to other concentrations.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.720-725
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• 2012

Sodium hypochlorite is used worldwide as a water disinfectant and in bleaching agent. Sodium hypochlorite applied to water initially undergoes hydrolysis to form free chlorine consisting of hypochlorous acid(HOCl) and hypochlorite ion($OCl^-$). For free chlorine determination, an electrochemical method is simple due to the electroactivity of free chlorine; it measures current and is free of most reagents. Amperometric free chlorine sensor has been developed with gold (Au)-based electrode. The 3-electrode free chlorine sensor whose working and counter electrodes were Pt exhibited excellent response to HClO at +400mV vs. Ag/AgCl/sat. KCl. In addition, the use of a pH error correction algorithm provided a reliable measurement of residual free chlorine in water sample without any pretreatment in the normal pH range(pH 6~8) of municipal water supply. The free chlorine sensor installed in on-line monitoring system could be used to continually monitor the level of residual free chlorine in real samples.

• Corrosion Science and Technology
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• v.19 no.2
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• pp.89-99
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• 2020

The inhibition of pitting corrosion failure of copper sprinkler tubes in wet sprinkler systems was studied. First, an apparatus and technology for removing air in the sprinkler tubes by vacuum pumping and then filling the tubes with water were developed. Using this apparatus and technology, three methods for inhibiting the pitting corrosion of the copper sprinkler tubes installed in several apartment complexes were tested. The first one was filling the sprinkler tubes with water bubbled by high-pressure nitrogen gas to reduce the dissolved oxygen concentration to lower than 2 ppm. In the second method, the dissolved oxygen concentration of water was further reduced to lower than 0.01 ppm by sodium sulfite. In the third method, the sprinkler tubes were filled with benzotriazole (BTAH) dissolved in water. The third method was the most effective, reducing the failure frequency of the sprinkler tubes due to pitting corrosion by more than 80%. X-ray photoelectron spectroscopy analyses confirmed that a Cu-BTA layer was well coated on the inside surface of the corrosion pit, protecting it from corrosion. A potentiodynamic polarization test showed that BTAH should be very effective in reducing the corrosion rate of copper in the acidic environment of the corrosion pit.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.275-280
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• 1998

The possibility of utilizing Porphyra yezoensis, Undaria pinnatifida and Laminaria religionsa into algae-tea having biological functionality was investigated by analysis of functional component, experimentation for low viscosity and various pretreatments. In water soluble fraction of powdered algae extracted for 3 minutes with 30 times of hot wate, major functinal components were composed of 1.53% porphyran and 170.04mg% taurine in P. yezoensis, 1.09% fucoidan and 1.18% sodium sodium alginate in U. pinnatifida, and 1.28% fucoidan, 1.99% soidum laginate and 371.25mg% iodine in L.religiosa, on dry basis. For lowering viscosity and masking off-flavor in each water soluble fraction, it was desirable that P. yezoensis was washed for 12 hours in sea water and 30 mimutes in fresh water, dried at 3 to 5$^{\circ}C$, powdered to size of 30 mesh nd then roasted for 3 minutes at 12$0^{\circ}C$, and that both U. pinnatifida and L. religiosa were washed, semidried to 40~50% moisture content, heated for 40 minutes at 12$0^{\circ}C$ by autoclave, dried, powdered to size of 30 mesh and then roasted for 5 minutes at 11$0^{\circ}C$.

• Journal of fish pathology
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• v.13 no.2
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• pp.97-102
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• 2000

In order to investigate the effect of chlorine disinfectant against white spot baculovirus (WSBV), 5, 10, or 30 ppm of sodium hypochlorite (NaOCl) was treated to the WSBV-infected shrimp, Penaeus chinensis. In contrast with the non-treated control, no shrimp was dead after of sodium hypochlorite treatment. This result indicated that WSBV was inactivated by chlorine treatment. No inactivation of WSBV was observed by 10, 20, 30 ppm of povidon-iodine treatment. WSBV was also inactivated by 2, 4 hr sunlight exposure and by 1, 2, 3 hr drying. WSBV was inactivated very effectively by addition of fresh water on sea water.

• Journal of Sensor Science and Technology
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• v.32 no.2
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• pp.67-74
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• 2023

A microfluidic paper-based analytical device (µPAD) is proposed for the selective detection of ammonia in water by using the modified Berthelot reagent and a fluidic channel consisting of hollow paper. The modified Berthelot reagents were uniformly dispersed in cyclohexane and then immobilized in a detection zone of the µPAD. The loading position of the reagents and the type of a sample flow channel were optimized to achieve a sensitive ammonia detection within a short analytical time. The NH₃ µPAD exhibits a linear colorimetric response to the concentration of ammonia dissolved in water in the range of 1-100 mg L^-1, and its limit-of-detection is 1.75 mg L^-1. In addition, the colorimetric response was not influenced by the addition of 100 mg L^-1 nitrogen containing compounds (sodium nitrate, sodium nitrite, uric acid, hydroxylamine, butylamine, diethylamine) or inorganic salts (NaCl, Na₂HPO₄), presenting the enough selectivity in the detection of water-dissolved ammonia against possible interferents.

• Clinical and Experimental Pediatrics
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• v.49 no.5
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• pp.463-469
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• 2006

Sodium is the major cation of the extracellular fluid and the primary determinant of extracellular osmolality. Therefore, hypernatremia causes water movement out of cells, while hyponatremia causes water movement into cells, resulting in cellular shrinkage and cellular swelling, respectively. Serious central nervous system symptoms may complicate both conditions. Since hypernatremia and hyponatremia are accompanied by abnormalities in water balance, it is essential to understand the mechanisms regulating extracellular osmolality and volume as well as the pathophysiology of hypernatremia and hyponatremia, in order to manage both conditions with swiftness and safety.

• Journal of the Korean Society of Safety
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• v.5 no.3
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• pp.39-43
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• 1990

The transport of phenol from waste water through the liquid surfactant membrane containing Aliquat 336 as a carrier was analyzed by a theoretical model. Extraction experiments was carried out to investigate the effect of process parameters, such as mixing intensity, concentration of sodium hydroxide in internal aqueous solution, and counter anions, and initial phenol concentration in waste water at $25^{\circ}C$. It was found that transport rate of phenol increased with increasing pH differents. The transport rate of phenol in waste water was influenced by counter anions.

• Journal of Korean Society on Water Environment
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• v.36 no.4
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• pp.275-283
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• 2020

Fecal coliforms are indicator bacteria to evaluate fecal contamination and microbiological safety in environment water. To examine fecal coliforms by membrane filtration, 1% rosolic acid solution dissolved in sodium hydroxide(0.2 M) should be added to m-FC medium according to Korean standard method. To reduce the exposure of researchers to harmful chemicals and expenditure of unnecessary cost, we evaluated if the rosolic acid solution is required to detect fecal coliforms. For 113 samples collected from five intake sources of Seoul, 42 samples of six tributaries, and 11 samples of sewage, the number of fecal coliforms was compared in medium with or without the reagent. As a result, the number was higher in m-FC medium without the reagent, but there was not a statistically significant difference. In the water intake, m-FC medium without the reagent could be used to examine fecal coliforms except in July, August and in case of rainfall. When heterotrophic plate counts exceeded 1,000 CFU/filter, or during rainfall, there was an effect of background bacteria in two types of the medium. However, it was more appropriate to use m-FC medium with the reagent to suppress gram-positive bacteria that can grow on medium without the reagent. In the tributary and sewage samples, the effect of the background bacteria was low, allowing the use of medium without the reagent regardless rainfall. Thus, it is necessary to present in standard method that the addition of rosolic acid solution in m-FC medium can be selected according to the characteristics of samples.

• Journal of Food Hygiene and Safety
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• v.8 no.2
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• pp.105-117
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• 1993

The objective of this investigation was to characterize the subacute toxic potency of orally administered poly(sodium acrylic acid-acrylic acid), super absorbent polymer. Four groups of rats were maintained on diets containing 0, 1.25, 2.5 or 5% of poly(sodium acrylic acid-acrylic acid). The mean dosages of poly(sodium acrylic acid-acrylic acid) were estimated to be 1025 mg/kg/day, 2009 mg/kg/day and 4728 mg/kg/day in the male groups. The estimated average dosages of poly(sodium acrylic acid-acrylic acid) in the female groups were 1011 mg/kg/day, 2088 mg /kg/day and 4576 mg/kg/day, respectively. Few test compound-related toxic effects were observed in body weight gain, clinical signs, hematological parameters and serum biochemical values. Urinalyses, gross necropsy and histopathology revealed no evidence of specific toxicity. Food and water consumption tended to increase in the animals fed the diet of 2.5% and 5%. Our data indicate that no-observed effect level of poly(sodium acrylic acid-acrylic acid) was estimated to be 1.25% in the diet (mean dosage: 1025 mg/kg/day in male rats, 1011 mg/kg/day in female rats).