• Clean Technology
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• v.16 no.3
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• pp.162-171
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• 2010

The objective of this study is to develop cleaning agents for the indoor water supply pipe which is environmentally friendly and suitable for removing scale by using various organic acids, inorganic acids, and some additives. Among various organic acids, oxalic acid, citric acid, and malic acid showed good cleaning efficiency of iron oxides which were main components of the indoor water supply pipe scale. Several cleaning agents were formulated by adding chemical additives into these organic acids and evaluated for removal of iron oxides. In this study, it was found that nonionic surfactants were excellent for the removal of iron oxide scale among various additives. Two types of cleaning agents($F_1$, $F_2$) with comparatively high solvent power for iron oxides were formulated in this study. The cleaning agents $F_1$ made by organic acids and some additives were formulated to be safe and environmentally friendly, but seemed to have disadvantage due to their comparatively low cleaning efficiency of iron oxide than $F_2$. But, the cleaning agents $F_2$ prepared by adding inorganic acid a little to $F_1$ showed comparatively good cleaning efficiency of iron oxide and could be recommended for removing hard scale of iron oxides in the indoor water supply pipe. Thus, it is considered that the formulated cleaning agents should be selected based on the extent of scale in the indoor water supply pipe.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.3
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• pp.59-65
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• 2005

There are accumulations of remained chemical additives and contaminants in the process water of semi-closed linerboard mill. High temperature of the process water aggravates the anaerobic digestion of contaminated process water and causes the generation of hazardous gases, which are from the biological reaction of varied additives and contaminants. The hydrogen sulfide in the gases easily combine with moisture in the air, and become sulfuric acid, which causes corrosion of paper machinery. This hydrogen sulfide is from the reduction of sulfate ions in the process water, and the sulfate ions are mostly from the alum. We changed the alum to PAC (Poly Aluminum Chloride). The results were preventing generation of hydrogen sulfide, and equivalent sizing effect by the use of PAC.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.453-460
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• 2018

The impact of sodium hydroxide, which is one of chemicals of clean in place (CIP) for removing membrane fouling, on the PVDF membrane is reviewed with respect to physical/chemical structural change, the permeability affected therefrom. Based on the cleaning concentration applied in membrane water treatment facilities, 10% of accumulated defluorination was confirmed up to 166g.hr/L which reflects the exposure time. However, membrane resistance was confirmed to be reduced by about 10%. Through FT-IR and EDS analysis, reduction of F and change of are confirmed as factors that affect the permeability of membrane. Membrane resistance, which affects permeability, is affected by loss of additives for hydrophilicity, rather than defluorination of PVDF material. Therefore, in order to check membrane degradation degree, an accelerated test by NaOH was carried out, loss of additives was confirmed, and then PVDF inherent characteristic was observed.

• Journal of Pharmaceutical Investigation
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• v.16 no.3
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• pp.101-105
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• 1986

The changes of water absorption and surface area of polydimethylsiloxane-5-fluorouracil devices containing different water soluble additives such as sodium chloride, glycerine, poly-propylene glycol(PPG 400), and polyethylene oxide(PEO 400, 400 and 2000) were investigated. It was confirmed that carriers controlled water absorption and swelling of the devices in the aqueous solutions. The water absorption and the swelling were affected by the osmotic pressure and ionic strength of the aqueous solutions.

• Journal of environmental and Sanitary engineering
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• v.22 no.4
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• pp.105-117
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• 2007

The research was conducted based on the 1012 cases questionnaire for the purpose of to evaluate the change effect of university student's consciousness and behavior before and after lecture on environmental problems. And this questionnaires were performed with self-administered by the university student who made a application for liberal arts related to environmental subjects. The results were as follows. According to the analysis results the most students responded that the most serious problem of environmental pollution before the lecture on environmental education was a genetic modified organism(3.64/4.00), but the most serious problem of environmental pollution was changed to the topic of water pollution(3.96/4.00) after the lecture on environmental problem. And also according to the analysis results dributed by gender were that boy students show a higher concerning(170%) than that of girl students(150%). The most good results obtained after lecture on environmental problem were water pollution(23.0%), air pollution(11.5%), waste material pollution(10.9%), food additives (10.0%), genetic modified organism(8.0%), endocrine disrupter(7.5%), respectively. And according to the analysis results distributed by a grade were that the concerning of a low grade(freshman, sophomore)were higher than that of a high grade(junior, senior) in the topic of water pollution, air pollution, waste material pollution. But there were high level of awareness on the topic of food additives, genetic modified organism, endocrine disrupter to the all students(freshman to senior). And according to the analysis results distributed by a major field of study were that students who major in art & athletics, liberal art and etc(public health) were show a deep concerning than that of science & engineering. Finally, the environmental education during the university class were effectively contribute to increase the awareness of the seriousness of environmental pollution problem(8.2%) and also contribute to the practical life after class also increase their consciousness of environmental problem(59.8%).

• Journal of Food Hygiene and Safety
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• v.14 no.3
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• pp.238-243
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• 1999

The storage stability from powdered anchovy and its preparation cooperated with three additives (water extract from green tea and boxthorn and BHT) was studied. The results are as follows: 1. When the additives were added to powdered anchovy, the storage stability was improved. The antioxidative activities of water extract from green tea and boxthorn were considerably higher than BHT. The antioxidative activities were decreased in the rank order boxthorn > green tea> BHT. 2. The more the concentration of natural additives was increased, the more the storage stability was improved. The rank order was$60^{\circ}>40^{\circ}>20^{\circ}$ Bx. 3. The A V and POV of powdered anchovy were increased in the rank order to 6 < 12 < 18 < 24 < 30 months by storage term. 4. This clearly suggested that water extract at $20^{\circ}>$ Bx level from boxthorn was possible utilization as a new natural antioxidant for storage stability of powdered anchovy.

• Journal of Ocean Engineering and Technology
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• v.22 no.1
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• pp.58-63
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• 2008

The effect of alkaline environmental condition on durability of GFRP composites according to additives was investigated. Additives used were polyvinyl alcohol(PVA), kaolin and alumina powder. Weight gains increased with immersion time in all GFRP composites at $80^{\circ}C$. But weight gain of specimen added PVA did not differ through the wlwle immersion time in both tap water and alkaline solution at 20 and $80^{\circ}C$. Tensile strength decreased with immersion time in all environment conditions. Tensile strength of GFRP composites regardless of additives decreased rapidly up to 5 days of immersion and then decreased slowly up to 30 days in alkaline solution environment at $80^{\circ}C$. Weight gains had not. much difference in both tap water and alkaline solution at $20^{\circ}C$. And weight gain of GFRP composites added polyvinyl alcohol had smaller than the others through the whole immersion time in both tap water and alkaline solution at $20^{\circ}C$ and $80^{\circ}C$. Tensile strength of GFRP composites added polyvinyl alcohol had higher than the others through the whole immersion time in both tap water and alkaline solution at $20^{\circ}C$ and $80^{\circ}C$.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.34-35
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• 1993

The study was undertaken to investigate the effects of ZnCl$_2$ in polysulfone(PSf)/N-methylpyrrolidone(NMP) on the structure and performance of its membrane. The effects of additives on the performances of membranes have been studied. It has been shown that some low molecular weight additives in polysulfone(PSf) casting solutions have effects on the performances of membranes cast from these solutions. It had been reported that ZnCl$_2$, as the additives-in PSf casting solution, decreases water permeability and increases the rejection rate of its membrane.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.3
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• pp.109-114
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• 1992

The purpose of this study is to experimentally research the effects of polymer additives on turbulent transition of Couette flow between concentric cylinders when outer one is rotating and inner one is at rest; the diameter ratio being 0.2. Aqueous polymer solution generate the degradation phenomena in machine forming work, but this is not effected in about 10 minute at 5ppm. aqueous polymer solution testing. The Reynolds number, referred to the gap distance and rotation velocity of the outer cylinder, of turbulent transition is about 20000 for water flow. In the laminer region, the torque value is as same as theoretical one in the region of low Reynolds number, but becomes high with an increase in the Reynolds number. The polymer additives reduce the Reynolds number for turbulent transtition. In the turbulent region, the torque is remarkably reduced by the polymer additives, soluble polymer take down effect of turbulent transition boundary torque.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.4
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• pp.1-7
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• 2003

In this study, fiber mechanical pretreatment before refining was executed with the addition of papermaking addiditives to find synergistic effects on fiber property improvement. Three fiber furnishes (SwBKP, KOCC, and BCTMP), and five different additives (CMC, CPAM, PEO, NaOH, $Na_2O_2$) were used. It was confirmed again that fiber mechanical pretreatment using Hobart mixer was a special way to modify fiber properties, where fiber WRV (water retention value) increases without losing fiber length. For SwBKP, addition of small amount of CMC (0.2％ OD basis), and for KOCC, PEO (0.2％ OD basis) caused additional significant improvement of the fiber furnish properties, respectively. Other additives did not cause adverse effects on the mechanical pretreatment, or better. For BCTMP, NaOH addition followed by mechanical pretreatment caused more than 20％ improvement in tensile and tear strength simultaneously, compared to the control. The yellowing caused by the treatment of NaOH on BCTMP could be minimized by using $Na_2O_2$ without losing the positive effect of NaOH.