• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.1
• /
• pp.31-39
• /
• 2007

The objective of this study was to investigate the inactivation characteristics of Cryptosporidium oocysts by ozone and UV and to suggest the better, disinfection method. The inactivation CT value of 1 log(90%) and 2 log(99%) in of one disinfection, which is an index of disinfection for inactivation effect by ozone, were respectively 5.77 $mg{\cdot}min/L$ and 21.30 $mg{\cdot}min/L$. The inactivation in UV disinfection was not affected by pHs(5, 7 and 9), low turbidity(5 and below NTU) and UV intensity(0.2 and 0.6 $mWs/cm^2$) but obviously decreased at high turbidity over 20 NTU. Therefore UV disinfection capacity can be obtained when a good turbidity removal in drinking water treatment process is achieved. And if oocysts is exposed by high UV over 0.6 mWs/cm2 during enough time, the better inactivation effect will be obtained.

• Journal of Energy Engineering
• /
• v.3 no.1
• /
• pp.18-27
• /
• 1994

석탄액화반응에서 촉매 세공구조가 촉매 불활성화에 미치는 영향을 조사하기 위하여 간단한 모델을 전개하였다. 촉매의 세공수 분포에 근거하여 두 개의 Dirac delta 함수분포를 갖는 다공질 촉매구조를 제안하였으며 촉매 세공구조와 반응속도상수와의 관계를 유도하기 위하여 단순화된 반응계를 가정하였다. 균일 코드피복 가정에서 본 모델을 촉매 불활성화 예측에 적용하였으며 계산과정에서 세공율, 세공 크기 등의 촉매 특성치에 대해서는 실제값을 이용하였다. 본 모델연구에 의하면 unimodal 촉매에 비해 bimodal 촉매가 촉매 불활성화에 덜 민감하였다.

• Microbiology and Biotechnology Letters
• /
• v.33 no.4
• /
• pp.302-307
• /
• 2005

The inactivation efficiency of Campylobacter jejuni were assessed in vitro and in vivo using confocal laser microscopy and flow cytometry. C. jejuni cells were inactivated with $1\%$ (w/v) trisodium phosphate (TSP) and the live cells and inactivated cells were distinguished by staining with LIVE/DEAD BacLight Bacteria Viability fluorescent probe. After treatment of TSP for 5 min, most of C. jejuni cells turned to coccoid form from original spiral shape. C. jejuni cells lost total cell viability in the absence of organic nutrients but did not lost total cell viability in the presence of organic nutrients. In vivo test, C. jejuni cells turned to viable but non-culturable (VBNC) form after TSP treatment and remained alive on chicken skin. C. jejuni cells attached on chicken meat would transform to coccoid form by sanitizer treatment, but could possibly be alive by the benefits of organic nutrients present in chicken meat.

• Korean Journal of Weed Science
• /
• v.6 no.2
• /
• pp.146-153
• /
• 1986

The study was conducted to estimate the oxyfluorfen inactivation proceeding which have or have not organism and soil microorganism in soil by biological testing method, under the different condition of soil class and temperature. The results obtained in this experiment are as follows: 1. Under the condition of high temperature, chemical`s inactivation resulted in early and the extent of it`s inactivation was increased. 2. The extent of inactivation was more rapid in the sandy soil than in the clay. 3. Among the soil class, the differentiation of the day of demand with inactivation at the 50% and 95% was significantly increased low temperature period. 4. In sandy soil, inactivation`s differentiation by adding organism was found, but by adding microorganism was not found. 5. In clay, chemical's inactivation was increased rather by adding microorganism than by adding organism. 6. Among under the condition of soil class, by adding organism and micrrorganism, chemical`s inactivation (Probit growing period at 50% and 95%) was shorted. And among the soil class, it was shortter sandy soil than clay or silty loam soil.

• Korean Journal of Food Science and Technology
• /
• v.9 no.2
• /
• pp.165-169
• /
• 1977

An apparatus for continuous sterilization of fluids in which heating-up and cooling time are negligible enabled determination of the kinetics of thermal inactivation of peroxidase for the range of temperatures $110{\sim}140^{\circ}C$. The enthalpy of activation was 146.4 kJ/mol; free energy of activation, 113kJ/mol; and the entropy of activation, 82.9J/mol.K. Comparisons of the experimental results with the thermal destruction time curves of microorganisms showed the possibility that the time required to inactivate peroxidase might be taken into account in evaluating thermal processes for commerciel HTST methods.

• Journal of the Korean Chemical Society
• /
• v.20 no.5
• /
• pp.406-416
• /
• 1976

A series of $N^1$-alkylnicotinamide chlorides, $N^1$-methyl-to $N^1$-dodecylnicotinamides inclusive were studied with rabbit muscle L-${\alpha}$-glycerophosphate dehydrogenase to investigate the possibility of reversible and irreversible inactivation of the pyridine-linked dehydrogenases by the coenzyme-competitive inhibitor derivatives. The inhibition of the enzyme by $N^1$-alkylnicotinamide chlorides was demonstrated to be reversible at the dilute concentration of the inhibitors but this reversible inhibition was found to be followed by an irreversible time-dependent inactivation measuable at high concentrations of the inhibitors. The properties of this time-dependent inactivation were discussed on the basis of the denaturation of the enzyme by the binding of small micelle-like structures formed at higher concentrations of the inhibitors.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.3
• /
• pp.466-469
• /
• 1995

The effect of lithium-ascorbate derivatives on viruses was investigated using a wide variety of bacterial viruses(phage). Lithium-ascorbate derivatives exerted an inactivating effect on all phages examined. Lithium-ascorbate derivatives have antiviral effects. The antiviral effect of lithium 2-o-octadecyl ascorbate was stronger than that of lithium ascorbate. Even at 10∼20 times lower concentration, the lithium 2-o-octadecyl ascorbate showed very much similar phage inactivating effect to that of ascorbate and lithium ascorbate.

• Journal of fish pathology
• /
• v.13 no.2
• /
• pp.97-102
• /
• 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 Korean Society of Environmental Engineers
• /
• v.29 no.9
• /
• pp.1020-1026
• /
• 2007

The control of pathogenic microorganisms is important issue in human environments, especially in surface area. However, surface disinfection has not been fully researched. In this study, the surface disinfection under UV irradiation was performed to investigate the quantitative kinetics for Bacillus subtilis spore inactivation in several experimental conditions, such as light intensity, temperature and surface roughness. This study reports that UV light would apparently inactivates the microorganisms and the required IT value for 2 log (99%) Bacillus subtilis spore inactivation was found to be 14.5 $mJ/cm^2$ in plain surface, as predicted by the Delayed Chick-Watson model. When UV was irradiated, there were no significant temperature effects. However, the experimental result shows that the more increased IT values are required at larger surface roughness.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.11
• /
• pp.1063-1068
• /
• 2010

This study compared UV and UV/$H_2O_2$ inactivation of E.coli, a possible indicator microorganism for fecal contamination of water, and $Q{\ss}$ phage, an indicator for pathogenic viruses. UV inactivation of $Q{\ss}$, T4 and lambda phages in actual secondary effluent was investigated, too. As a result, similar inactivation efficiency between $Q{\ss}$ phage and E.coli was observed during UV treatment, while $Q{\ss}$ phage showed higher resistance to UV/$H_2O_2$ than E.coli. $Q{\ss}$ phage resistance to UV or UV/$H_2O_2$ does not reflect those of all pathogenic viruses. However, the result tells that the use of E.coli inactivation efficiency in evaluating microbiological safety of water could not always ensure the sufficient safety from pathogenic viruses. Meanwhile, $Q{\ss}$ phage showed less resistance to UV than T4 and lambda phages, indicating that the use of $Q{\ss}$ phage as an indicator virus may bring insufficient disinfection effectiveness by causing the introduction of lower UV dose than required. Consequently, it can be thought that T4 or lambda phages would be more desirable indicators in ensuring the sufficient disinfection effectiveness for various pathogenic viruses.