• Resources Recycling
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• v.30 no.2
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• pp.61-67
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• 2021

Scraps are a byproduct of the machining process used for transforming titanium ingots into useful mechanical parts. Scraps take two forms, namely, bulky scraps, which are produced by cutting, and chipped scraps, which are produced by milling. Bulky scraps are comparatively easier to recycle because of their small surface area and less oxygen content; as a result, they pose only a small risk of explosion. In contrast, chipped scraps pose a higher risk of explosion, because of which, their recycling is complicated, resulting in most such scraps being discarded. With the aim of avoiding this waste, we proposed a novel process for converting chipped scraps into stable carbide materials. Methods typically applied to reduce particle size and impair the formation of solid solution type phase in the carbide materials were used to improve the mechanical properties of carbides prepared from chipped scraps. Our novel recycling process reduced carbide production costs and improved carbide quality.

• Clean Technology
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• v.18 no.3
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• pp.272-279
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• 2012

In this study, an environmental-friendly cleaning agent utilizing organic acids and various additives has been developed and applied to the field for removal of scale deposited on the cleaning beds or distribution reservoirs of the waterworks. As an analytical result of scale on the cleaning beds, we found that it consists of mainly metallic oxides such as $SiO_2$, $Al_2O_3$, $Fe_2O_3$, and MnO. Malic acid, malonic acid, and citric acid showed relatively better solvency on $Al_2O_3$, $Fe_2O_3$, and MnO except $SiO_2$ among various organic acids. Mixed organic acid solutions of malic acid, malonic acid, and citric acid were prepared with certain weight ratios and their solvencies on mixed metal oxides of $Al_2O_3$, $Fe_2O_3$, and MnO were investigated. The experimental results showed that an 10% mixed organic acid solution prepared with weight ratio of malic acid : malonic acid : citric acid = 6 : 2 : 2 were found to have best scale solvency power of about 29%. The formulated cleaning agents with a small amount of nonionic surfactant showed much better solvency on mixed oxides than mixed organic solution alone. Especially, the formulated cleaning agent with 0.2 wt% LA-7 surfactant appeared to have best scale removal efficiency of about 35%. However, the formulated cleaning agent with disinfectants such as NaClO, $H_2O_2$ and $Ca(ClO)_2$ showed poor solvency on mixed oxides. It is inferred that surfactants are able to improve scale removal efficiency due to their capability of emulsification, and disinfectants cause to degrade scale solvency in water because of their oxidation. Based on these basic experimental results, formulated cleaning agents have been prepared with mixed organic acid solution, nonionic surfactants, and disinfectants and successfully applied to removal of scales on the cleaning beds and distribution reservoir at city D waterworks.

• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.338-345
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• 2007

This study surveyed on the actual conditions of using sanitizers and disinfectants for improvements of sanitization on food utensils at 105 school and 20 industry foodservice operations. The questionnaire which was administered to 125 foodservices was used as a mail or visitation method. The answers of asking "Perception on temporary authorization system of sanitizers and disinfectants on food utensils" were 75% in contract managed school foodservices, 81.8% in self operated school foodservices, and 50% in industry. Main factors to choose sanitizers were sterilizing power (38.6%, 28.6%, 38.9%) and safety (32.6%, 46.1%, 33.3%) at every foodservices. Keeping ratio of sanitizers and disinfectants guidelines in contract managed school, self operated school and industry foodservices were 64.8%, 52% and 73.7%, respectively. If easy and practical guideline is developed, most foodservices replied to use if for disinfection of foodservices. Most of the foodservices were not only knowing sanitizers and disinfectants but also possessing a guideline. However, they didn't perform disinfection according to the guideline due to its complexity. Consequently, we suggest that it is necessary to provide an easy and practical "sanitizers and disinfectants guideline" and useful information.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.2
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• pp.230-237
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• 2003

For hygenic evaluation, microbiological tests of seasoned raw vegetal)les from five high school foodservice operations were conducted. The antimicrobiological effect of pre-preparation with vinegar against microorganisms on vegetables in foodservice operations was also investigated. Total plate counts of leek gukgalli, broad bellflower saengchae and vegetable salad ranged from 10$^4$ CFU/g to 10$^{6}$ CFU/g. Coliform levels of those ranged from 10$^2$CFU/g to 10$^4$ CFU/g. Leek washed three times was pre-prepared at different concentration (0.05%,0.1%,0.5%,1% and 2%) and temperature ( 1$0^{\circ}C$ 2$0^{\circ}C$ and 4$0^{\circ}C$) for 5, 10 and 30 minutes. The higher the concentration and temperature of vinegar were, the more the antimicrobiological activity increased. The sanitizing activity of vinegar increased with treatment time. Considering the quality of vegetable and the expense, when the levels of total plate counts and coliform of vegetable were 10$^{6}$ and 10$^3$ CFU/g, pre-preparation with 0.5% of vinegar at 2$0^{\circ}C$ for 10 minutes was best. The population of total plate count and coliform on row and leek washed three times increased during storage for 72 hours. However, The levels of microorganism on leek samples pre-prepared with 0.5% and 1% vinegar decreased during storage. After the treatment of vinegar at 1$0^{\circ}C$ for 10 minutes, Staphylocucus aureus, Escherichia coli O157, Shigella sonnei, Salmonella entritidis, Listeria monolytogenes were not detected.

• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.365-369
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• 2007

This study was conducted to seek optimum concentration and treatment time of fermented rice water (Rizen) to disinfect food-borne bacteria in kitchen towel. $2.65\;log_{10}cfu/g$ of E. coli was reduced when double or triple diluted fermented rice water was treated during 2 hours. In case of concentrated fermented rice water, crude and double diluted solutions showed complete sterilization after 2 and 5 hours, respectively. On the other hand, triple, quadruple, quintuple diluted solutions needed 24 hours for complete sterilization. The effect of fermented rice water as a disinfectant was compared with water, detergent and chlorine treatment against E. coli and S. Typhimurium contaminated in kitchen towel. The initial number of E. coli in untreated kitchen towel were $5.0\;log_{10}cfu/g$ and were decreased to 4.32, 3.70 and 3.02 by treatments of water, detergent and chlorine, respectively. The double and triple diluted fermented rice water and double diluted concentrated fermented rice water also reduced the E. coli in kitchen towel to 2.43, 2.30 and $1.88\;log_{10}cfu/g$, respectively. The initial number of S. Typhimurium in untreated kitchen towel were $4.80\;log_{10}cfu/g$ and were decreased to 4.12, 3.58 and 2.81 by treatments of water, detergent and chlorine, respectively. The double and triple diluted fermented rice water and double diluted concentrated fermented rice water also reduced the E. coli in kitchen towel to 2.14, 2.03 and $1.59\;log_{10}cfu/g$, respectively. Consequently, the fermented rice water is thought to be a good disinfectant to reduce food-borne bacteria like E. coli and Salmonella contaminated in kitchen towel.

• Proceedings of the Korean Society of Food and Cookery Science Conference
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• 2003.05a
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• pp.101-101
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• 2003

우리나라 식단에서 예로부터 널리 이용되어 온 건어물 중 서울시내 급식소 12곳에 입고 된 쥐어채, 오징어채, 북어채를 대상으로 미생물학적 위해분석을 실시하여 원재료의 오염실태를 조사한 후 최종조리음식의 안전성을 확보하기 위해 조리공정 전에 적용할 수 있는 세척, 볶기, 데치기, 전자레인지 가열 둥의 전처리 과정을 적용하여 효과적으로 위해를 제거할 수 있는 방법을 모색한 결과 일반세균의 경우 취어채는 1.2$\times$$10^3$~8.2$\times$$10^{6}$ CFU/g, 오징어채는 2.2$\times$$10^4$~3.3$\times$$10^{8}$ CFU/g, 북어체는 4.0$\times$$10^2$~1.7$\times$$10^{6}$ CFU/g 범위로 검출되었고, 대장균군의 경우 쥐어채는 1.0$\times$$10^3$~3.4$\times$$10^4$ CFU/g 범위로, 오징어채는 $10^1$ CFU/g 이하에서 1.4$\times$$10^4$ CFU/g 까지, 북어채는 $10^1$ CFU/g 이하에서 4.5$\times$$10^3$ CFU/g 까지 검출되어 전체적으로 위생상태가 불량한 경우가 많은 것으로 평가되었다. (중략)

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.58-66
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• 1997

In order to evaluate the exact effect of detergency it is necessary both to measure the actual soil content by chemical analysis and to determine the degree of soil removal visually. Since it takes considerable time and effort to use both methods, usually one of the two methods is used. Many studies have been carried out through increasing the visibility of oily soil to evaluate detergency by measuring reflectance of fabrics. In this study Sudan Black B, an oil soluble dye was used as an indicator to increase the visibility of oily soil on cotton and polyester fabrics. The condition of artificially soiled fabrics and the method of evaluating detergency were investigated which represent the actual detergency of oily soil by measuring the reflectance only. Also the detergency of Sudan Black B and that of oily soil were compared with each other under various washing conditions, As a result, the K/S values converted from the reflectances showed a good correlation with the actual soil content. Linear relationship between K/S value and the actual soil content was obtained. The K/S values of washed fabrics were higher than those of unwashed fabrics which included same content of soil since the soil visibility changed during washing. But the difference was small when Sudan Black B was used. With the increase of soil content, detergency of cotton fabric decreased, but detergency of polyester fabric increased gradually. With regards to soiled fabrics, detergency of cotton fabric measured by K/S value was close to that of actual oily soil when Sudan black B was used as an indicator.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.441-451
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• 2014

The flushing is important to maintain good water quality in water main. It is a technique of using water velocity to remove sediments in water distribution system. The variety of water quality problems can occur in a distribution system, so too can a variety of benefits be gained by system flushing. In order to effectively perform the flushing, the contaminants to be removed to set up and it can be solved, it is necessary to ensure the proper flow rate. In this study, the removal of contaminants present in the inner water pipe attached loose deposits such as fine particles of granular activated carbon, sand and iron corrosion product sought to derive flow rates. Thus, the constant observation of using pilot plant scale water distribution plant for the movement of floating characteristics of particles were assessed.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.440-448
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• 2005

Physical and chemical properties of waste glass, such as bottle glass, plate glass, and LCD glass were investigated to test the feasibility of starting materials for the production of high quality foamed glass for insulating grade construction material without pre-treatments such as cleaning, and waste removals. For this purpose, chemical analysis, thermal analysis, crystalline analysis, and rheological analysis including viscosity were proceeded and the preparation of foamed glass under the qualitative conditions obtained from these various analysis was also attempted. Overall results of various analysis and investigations for these waste glass showed that waste bottle glass and plate glass have high possivility of use as feed materials for the production of foamed glass.

• Analytical Science and Technology
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• v.13 no.3
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• pp.332-337
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• 2000

The study on the nitrogen adsorption, surface properties and water adsorption capacity of the carbonaceous desiccants derived from phenolic resin was carried out. In the nitrogen adsorption study on the carbonaceous desiccants, Type II isotherm for each sample was obtained. Furthermore, the adsorbed volume decrease with water washing of the desiccant. The $S_{BET}$ of the carbonaceous desiccants was $648.7m^2/g$ before washing and $189.3m^2/g$ after washing, respectively. The morphology of needlelike formation before washing and spherical particle after washing with water were observed from SEM micrographs. Finally, from the water adsorption effects, the percentage of the water loading capacity was 25-63%, and the capacity was good at relatively low humidity.