• Journal of the Korean Society of Safety
• /
• v.22 no.1 s.79
• /
• pp.24-29
• /
• 2007

The effectiveness of a UV(ultra violet) disinfection system depends on the characteristics of the waste water, flow conditions, the intensity of UV radiation, the amount of time the microorganisms are exposed to the radiation, and the reactor configuration. The wast water flow conditions are important factors in the design of UV disinfection system from the point of enhancement view of UV disinfection. The turbulent energy intensity in the wake by the vortex shedding are effective for UV radiation. Therewith the effectiveness of vortex generator is considered as a enhancement of UV disinfection. The experimental results presented give important evidences and explain that it is possible to predict UV disinfection performance based on flow experiments. An experimental investigation of two types of the vortex generator is presented. The qualitative and quantitative evaluations of the wake are made by flow visualization using smoke wire method and the measurement of vortex frequencies in the wind tunnel. From the experiment, following results were obtained that the delta wing type vortex generator is more effective than circular type because of the higher vortex frequencies and the smaller drag.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.319-324
• /
• 2006

The purpose of this study Is to evaluate the efficacy of multizone simulation that enables to grasp of details about microbial contaminant problem in an multistoried apartment. We used actual indoor test data to figure up microbial contaminant level as initial value for the multizone simulation and estimated the various effects of indoor occupant infected with germs and the performance of air sterilization by using multizone simulation in substitute for infeasible experimental approach. The results show that natural ventilation make ourselves generally useful for removing indoor microbial contaminants. The results also show that the performance of air sterilization reach the maximum in the case of using mechanical ventilation and UVGI air sterilizer. The conclusion is that this multizone simulation is useful tool for actual design method for Immune building systems.

• Membrane Journal
• /
• v.10 no.2
• /
• pp.75-82
• /
• 2000

This study, which was tarried out to investigate the characteristics of permeation rates and fouling phenomena in drinking-water treating processes with MF membrane, showed that pressure drop was dependent on the length of membrane module and operating pressure; the pressure drop increased with the length of membrane module and operating pressure, operation at a relatively low pressure(0.5kg/$cm^2$) is better than that at a relatively (2.0kg/$cm^2$), since high operating pressure accelerates the clogging. In case of out-in permeation type, almost same flux was obtained after a certain operating time regardless of membrane length and operating pressure. In order to understand, the microbial fouling, chemical cleaning was carried out to the forced contaminated hollow-fiber membrane with chemicals($H_2O_2$, NaOCl, and NaOH). Chemical cleanings with $H_2O_2$and NaOCl, which are oxidizing agents, are better for sterilizing and desorbing the microbes than those with NaOH.

• The Journal of Natural Sciences
• /
• v.11 no.1
• /
• pp.41-44
• /
• 1999

For the purpose of improving the UV sterilization for toothbrush, the sterilizing effects by the UV light were studied. When toothbrushes were treated with the UV light for 5, 15, 30, 60 minutes, the sufficient antibacterial effect were shown after 15 minutes with 80% of bactericidal effects. To prevent the brownish stain on the sterilizer which was caused by the long exposure of UV light, no UV treatment for two hours after 15 minutes exposure were scheduled and then 3 minutes re-exposure were performed, which showed 97% of bactericidal effect. Also, the antibacterial effects of the sterilizer showed different results depending on the position of the toothbrush, it was recommended to adjust toothbrush to be exposed by the UV light directly.

• Land and Housing Review
• /
• v.14 no.4
• /
• pp.103-110
• /
• 2023

People who spend most of their day indoors are continuously exposed to internally and externally generated indoor pollutants. According to a 2022 report from the World Health Organization (WHO), air pollution is the cause of more than 7 million deaths annually worldwide, emphasizing the seriousness of indoor air pollutants. Air pollutants include nitrogen oxides (NOx), formaldehyde (HCHO), and volatile organic compounds (VOCs), which have serious effects on the human body. Photocatalyst is a material that can remove these indoor air pollutants. Photocatalysts not only have the ability to remove dust precursors, but also have antibacterial, sterilizing, and deodorizing functions, making them effective in improving indoor air quality. This study suggests areas and methods in which photocatalysts can be applied to buildings. Fields of application include interior and exterior construction materials such as concrete, as well as organic paints and ventilation devices. If appropriate utilization plans are developed, it may be possible to improve the built environment through reduced indoor and outdoor pollutant levels.

• Journal of the Korean Institute of Gas
• /
• v.14 no.3
• /
• pp.1-7
• /
• 2010

According to Indoor Air Quality(IAQ) management law for multi-use buildings, SEEONE CO., Ltd. made pilot and tested it to remove minute particle, odor, VOCs, etc. within the standards of IAQ. This pilot made by SEEONE CO., Ltd. is vortex scrubber washing electrolyzed water. As 30 minutes test result in multi-use building indoor place, minute particle(the smoke of a cigarette) was reduced $920{\mu}g/m^3{\rightarrow}112{\mu}g/m^3$, gaseous contaminants was reduced Formaldehyde (HCHO) 20ppm$\rightarrow$4ppm, Ammonia($NH_3$) 50ppm$\rightarrow$1ppm, Trimethylamine ($(CH_3CH_2)_3N$) 15ppm$\rightarrow$trace, Methylethylketone($CH_3COC_2H_5$) 25ppm$\rightarrow$trace, Acetic acid ($CH_3COOH$) 20ppm$\rightarrow$trace, Acetaldehyde($CH_3CHO$) 15ppm$\rightarrow$2ppm and Acetone($CH_3COCH_3$) 50ppm$\rightarrow$N.D. The pilot test result of the air filter using electroyzed water in vortex scrubber showed high removal efficiency. Because purified air maintain indoor humidity of approximately 40~60%, so users can feel pleasant. In E.coli, S.aureus sterilization test and CODcr, turbidity treatment test by electrolysis, germs was sterilized over 99.99% and CODcr and turbidity was decreased gradually. So water used for washing can be reused by electrolysis.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.1 no.2
• /
• pp.136-143
• /
• 2013

In the sewage structures and wastewater facilities, concrete is exposed to hydrogen sulfide ($H_2S$) which acts as an acid material in a solution, and a strongly acidic sulfate ion ($SO{_4}^{-2}$) is generated by a sulfuric bacteria. Hence, a degradation of concrete with biochemical corrosion would be accelerated. Finally, durability of concrete and concrete structures may be greatly reduced. In this study, in order to remove the hydrogen sulfide which is used by the sulfuric bacteria organic-biologically, the antibiotic metal and metallic salt powders were mixed to concrete, and a suppressing performance of the sulfate ion was assessed. For the sulfuric acid bacteria, a comparative evaluation of antimicrobial performance on neutralized concrete specimens were carried out, also by a rapid chloride penetration test, chloride penetration depths and diffusion coefficients were measured for antibiotic concrete in accordance with the amount of metal and metallic salt-based antibacterial agents. Eventually, by an observation of the biochemical state of the surface of concrete specimens exposed outdoors, the performance and applicability of antibiotic concrete were confirmed.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.6
• /
• pp.263-268
• /
• 2005

The ceramic balls impregnated with $20{\sim}40nm$ sized Ag colloid were examined for heavy metals absorption and antibacterial activities in the drinking water. The preparation conditions of ceramic ball that the porosity was excellent were as follows: starting material: 85 wt% $Ca_{10}(PO_4)_6(OH)_2$, binder: 5 wt% PVA and 15 wt% ${\alpha}-Ca_3(PO_4)_2$, heating temperature: $1000^{\circ}C$, duration: 3 hrs. The ceramic balls obtained under these conditions showed specific surface area of $110m^2/g$, pore size of $120{\mu}m$ and porosity of 80%. Also, as the results of a performance test on a rate of adsorbing and removing heavy metals in the drinking water by using the.AAS, heavy metals such as Zn, Mn, Fe and Cu were removed to the extent that their content became 0.03mg/l or lower after 1 day and they showed an excellent bactericidal activity that all coliforms were killed after 3 hrs.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.1
• /
• pp.142-151
• /
• 2017

Cationic surfactants have a bactericidal effect and the study for effective development of them became important parts in the industry. There have been increasing researches that focus on the development of products having not only outstanding features but also safety and biodegradability. In this work, novel ester-type cationic surfactants were obtained via Michael addition reaction. Intermediates were quantitatively prepared by the Michael addition reaction between alkyl acrylate and amine compounds under mild conditions without solvent and catalyst. The intermediates were quaternized with dimethyl sulfate. HQ21 with two hydrophobic groups and a hydrophilic group and HQ22 with two hydrophobic groups and two hydrophilic groups were obtained. The structures of the products were characterized by 1H-NMR, HR-MS and FT-IR and biodegradability of the products were tested.

• Analytical Science and Technology
• /
• v.10 no.5
• /
• pp.343-349
• /
• 1997

Analytical method using the reversed phase ion-pair chromatography (RP-IPC) for the determination of kasugamycin(5-amino-2-methyl-6-(2,3,4,5,6-pentahydroxy cyclohexyloxy)tetrahydropyran-3-yl-amino-${\alpha}$-imino acetic acid), pesticide as fungicide bactercide has been established. The retention behavior of kasugamycin in the RP-IPC was examined with respect to the effect of concentrations of organic modifiers, pH of eluent and types and concentrations of the counter ions as ion-pair reagent. This method developed by the optimum factors, can be used for the application of the quality control in the crude product and its formulation.