This study examined the effect of ultraviolet (UV) application on bacterial disinfection in a commercialized humidifier using ultrasonic wave (UW). To accurately examine disinfection kinetics in tap-water condition, tap-water was sterilized using a filter, and then inoculated with pure cultures of E. coli and P. putida with known viable counts. The disinfection kinetic characteristics were experimentally compared when UV alone, UW alone, and UW+UV together were applied in disinfecting the added bacteria in the commercialized humidifier. When UV alone was applied, bacterial disinfection kinetics followed a first-order decay reaction, and showed an approximately 10-time weaker disinfection compared to the typical UV disinfection in water treatment or wastewater treatment. When UW alone was applied, bacterial disinfection kinetics followed a second-order decay reaction with a low disinfection rate constant of 0.0002 min-1(CFU/mL)-1. When UV and UW were applied together, however and interestingly, the disinfection rate constant (0.0211 min-1(CFU/mL)-1) was approximately 100 times increased than that for the UW alone case. These results revealed that the co-use of UV and UW can provide synergistic effect on bacterial disinfection in a tap-water condition in household humidifiers.
본 연구에서는 알루미나 정밀여과 및 광촉매 코팅 폴리프로필렌의 혼성 수처리 공정에서 물역세척 시간 (back-flushing time, BT) 및 PP 구 변화의 영향을 알아보고, 알루미나 한외여과막와 동일한 PP 비드를 사용한 선행 결과와 비 교하였다. 물역세척 주기(FT)는 10분으로 고정한 채, BT를 6~30초로 변화시키면서, 그 영향을 180분 운전 후 막 오염에 의한 저항(Rf), 투과선속(J)과 총여과부피(VT) 측면에서 고찰하였다. BT가 길어질수록 Rf는 급격히 감소하고 J는 증가하였으나, VT는 BT 10초일 때 최대였다. 탁도의 처리효율은 99.0% 이상으로 BT의 영향이 보이지 않았다. 한편, 유기물 처리효율은 역세척 없 는 조건(NBF)에서 89.0%로 가장 높았으며, BT가 길어질수록 증가하였다. 막오염 측면에서 최적 PP 비드의 투입 농도는 20 g/L이었으나, 알루미나 한외여과막와 동일한 PP 비드를 사용한 선행 결과 최적 PP 비드의 농도는 40 g/L이었다. 탁도와 유기 물 처리효율은 PP 농도 30 g/L에서 최대였으나, 선행 결과 탁도와 유기물 처리효율은 모두 PP 농도 40 g/L에서 가장 높았다.
Environment-friendly agricultural products are consumed widely, but little is known about consumers’ acceptability. The objectives of this study were to 1) determine consumers’ acceptability of cucumber when consumed raw, 2) determine differences in appearance liking between environment-friendly and conventionally grown cucumber samples, and 3) analyze the physicochemical properties of cucumber. White dadagi, gasi, non-pesticide mini cucumber, organic gasi, and organic Joseon cucumber samples were evaluated for consumers’ acceptability using a nine-point hedonic scale; White dadagi, organic Joseon, and organic gasi cucumber samples showed the highest acceptability scores. However, there were three consumer segmentations differing their degree of cucumber liking and preference. Consumers liked the appearance of organic gasi best. Consumers’ preference of cucumbers did not change upon evaluation of the acceptability of the appearance of whole fruit with and without a label indicating an environment-friendly status. Additionally, the physicochemical properties of the cucumbers—including color (skin and flesh), length, circumference, weight, water activity, brix, and texture (hardness and fracturability)—were measured. All measurements showed significant differences among samples, with the exception of water activity and hardness. White dadagi was 3.8 brix, which was the highest among cucumbers, followed by non-pesticide mini cucumber and organic Joseon. White dadagi, organic Joseon, and organic gasi showed greater fracturability than the other cucumber samples.
Two fractions (permeate and retentate) from fiber free Aloe vera gel were prepared using an ultra-filtration (UF) system with a tubular ceramic membrane (MWCO of 50 kDa), and their dilute solution properties were investigated. The intrinsic viscosities of fiber free Aloe vera gel and the retentate and permeate fractions that were prepared by ultra-filtration were 18.48, 37.74, and 2.01 dL/g, respectively. UF aloe retentate as a polysaccharide rich fraction exhibited polyelectrolyte behavior showing a sharp decrease of intrinsic viscosity by the addition of NaCl. However, as its NaCl concentration increasing to 1 M, its intrinsic viscosity slightly increased due to conformational change caused by the high concentration of NaCl. On the one hand, the intrinsic viscosities of the dilute UF-retentate solution were exponentially decreased with increasing temperature, and the temperature dependency of its intrinsic viscosity showed a sharp discontinuity at 30oC instead of a linear Arrhenius behaviour, indicating a variation of flow mechanism or network rearrangement of a molecular chain. The chain stiffness of polysaccharide rich fraction at bellow and above 0.5 M of NaCl addition was 0.048 and 0.515, respectively, showing different stiffenings and significant conformational change. The coil overlap parameter and critical concentration of UF-retentate were 3.0 and 0.08 g/dL, respectively.
In vitro physiological functions such as jack bean (Canavalia ensiformis) urease inhibitory activity and retarding effect of glucose/bile acid of Aloe vera gel concentrated by the optimized DIS (Dewatering Impregnation & Soaking) process conditions were examined. Urease inhibitory activity of DIS aloes ranged from 84.6 to 94.4%, which was similar to or higher than 86.3% of fresh aloe. Also, urease inhibitory activity of DIS aloes was maintained at initial levels after heat treatment (90oC, 10 min.) and drying treatment (freeze or hot air drying). Urease inhibition pattern from Lineweaver-Burk plot indicated general non-competitive inhibition, and inhibition constants (KIE and KIES) of DIS aloes were 41-149 and 87-163 μL/mL, respectively. DIS(glucose) and DIS (polyethylene glycol) exhibited the highest retarding effect of glucose and bile acid. Their retarding effects were about 1.6 and 1.8 folds higher than that of fresh aloe after 0.5 and 1 hr of the dialysis, respectively. Conclusively, the above in vitro physiological functions of Aloe vera gel concentrated by DIS process suggested that aloe products treated with DIS would have the potential benefits for protection against Helicobacter pylori and reduction of blood glucose and cholesterol levels.
The structural and physicochemical properties of dried aloe vera gel by DIS (dewatering impregnation soaking) process under optimum conditions were investigated. FT-IR spectra for dried samples of DIS aloes showed the typical patterns of standard aloe polysaccharide, and surface structures by SEM (scanning electron microscopy) were similar to a gel-like structure. In case of physicochemical properties of dried aloe samples by DIS process, solubilities and swelling powers of control (not osmotic treated aloe), DIS (S) and DIS (G), samples treated by osmotic solution of 60% sucrose/0.25% NaCl and 50% glucose/0.5% NaCl, were 48.3-57.3% and 8.3-11.7%, respectively, showing no significant differences among samples, but swelling power of DIS (PEG), sample treated by using 50% polyethylene glycol as an osmotic agent was about 5 times higher that of control. Also, water holding capacities of control, DIS (S) and DIS (G) were similar to each other, but that of DIS (PEG) was about 5 times higher that of control. Oil holding capacities of control and DIS aloes maintained the 50.9-86.4% levels of water holding capacities showing no significant differences among samples. Rehydration ratio of DIS (PEG) aloes were significantly dependent on the temperature of rehydrated solvent (water), and rehydration ratio of not-fileted aloe was about two folds higher than that of fileted aloe.
A study was carried out on the distribution of chlorophyll a and water quality in the dry season in Yosuhae bay and adjoining sea, Southern Korea, in July of 1994.
Concentration of salinity and phosphate were lower in the outer bay than in the inner bay. While nitrate and silicate were higher in the former than in the latter. We were identified with coastal water of origin from China with the lower salinity in outer bay. The China coastal water was characteristic of high nutrients and phytoplankton biomass, such as chlorophyll a.
The principal component analysis (PCA) on the analytical data proved that high density of phytoplankton biomass occurred under the condition of low salinity and high concentration of dissolved inorganic nutrients.
It is thought that the thermoharine structure and biological produtions of Yosuhae bay were controlled by the China coastal water in the outer bay.