• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.488-493
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• 2004

The effects were examined from several conditions of $TiO_2$ photocatalysis reaction to phenols degradation by changing it's reacting conditions such as phenol concentration, pH, $TiO_2$ concentration, $H_2O_2$ concentration, flow rate, and intensity of ultraviolet rays. Phenol degradation was more efficient in low concentration of phenol, neutral pH. Phenol degradation appeared to increase as concentration of $TiO_2$ photocatalyst, that of $H_2O_2$ and intensity of ultraviolet rays increased. As $TiO_2$ dosage increased, initial rate constant k linearly increased. When $H_2O_2$ was injected more than optimum, phenol removal rate didn't increase in proportional to the change of $H_2O_2$ concentration as OH radicals was being consumed. When flow rate is less than $4.75m^3/m^2$ day, phenol removal efficiency appeared to decrease as ultraviolet rays transmission rate becomes low by $TiO_2$ suspension coated in photo reaction column. Meanwhile, initial rate constant according to light intensity change in less than $25mW/cm^2$ appeared to be in proportion to light intensity ($mW/cm^2$) Removal efficiency decreased about 12% after 180 minutes of reaction time while showed stable removal efficiency of 100% after 300 minutes when using regenerated $TiO_2$.

• Journal of Environmental Science International
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• v.18 no.6
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• pp.667-674
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• 2009

This study has carried out to evaluate the effect of NaCI as electrolyte of single (electrolysis and UV process) and complex (electrolysis/UV) processes for the purpose of removal and mineralization of Rhodamine B (RhB) dye in water. It also evaluated the synergetic effect on the combination of electrolysis and UV process. The experimental results showed that RhB removal of UV process was decreased with increase of NaCl, while RhB removal of electrolysis and electrolysis/UV process was increased with increase of NaCI. The decolorization rate of the RhB solution in every process was more rapid than the mineralization rate identified by COD removal. The latter took longer time for further oxidation. Absorption spectra of an aqueous solution containing RhB showed a continued diminution of the RhB concentration in the bulk solution: concomitantly, no new absorption peaks appeared. This confirmed the decolorization of RhB, i.e., the breakup of the chromophores. It was observed that RhB removal in electrolysis/UV process is similar to the sum of the UV and electrolysis. However, it was found that the COD of RhB could be degraded more efficiently by the electrolysis/UV process than the sum of the two individual process. A synergetic effect was demonstrated in electrolysis/UV process.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.421-424
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• 2002

Deterministic and probabilistic approaches to the design of ultraviolet (UV) disinfection system for water reclamation are reviewed and discussed. The high inactivation of TC, FC and E. coli by UV disinfection was demonstrated and the inactivations of TC, FC and E. coli were 97%, 98% and 99%, respectively. Within the range of 0.3-4.5mWs/cm, the effect of UV does on the inactivation ratio was not observed. However, in the highest wattage of UV lamp, 39W, the inactivation ratio of TC, FC and E. coli was 100%, regardless of the UV does so the UV density was more effective on inactivation ratio of TC, FC and E. coli rather than UV does. Under the 0.4 mWs/cm and 16W of UV lamp, the effect of dissolved organic matter and turbidity on the inactivations of TC, FC and E. coli could not be observed in this study within the range of 0-60mg/L and 0-40 NTU respectively.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.521-533
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• 2012

Interest in application of ultraviolet light technology for primary disinfection that used for the treatment of water for consumption and wastewater has increased significantly in recent years. Analysis of these systems has been carried out using Computational Fluid Dynamics (CFD) procedure. It offers advantages over other techniques in specific circumstances. CFD has emerged as a powerful tool to aid design of a UV reactor by providing the UV dose delivered by the proposed reactor design and allowing engineers to evaluate alternative designs in much less time and at a reasonable cost. In this study, five different configurations of the apparatus depending on the location of the exit are evaluated in terms of maximum dose, minimum dose, flow patterns, particle tracks and transient dose. The configuration 3 results have higher minimum UV dose value and uniform particle distribution of the UV dose on the outlet than other's.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.576-585
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• 2020

This study quantitatively investigated the increase in ballasting time through numerical calculations when an ultraviolet (UV) ballast water management system (BWMS) is installed on an existing vessel. The calculation results indicate that the ballasting time of a gas carrier having 55,000 dead weight tonnage was 2.152 hours without installation of the UV BWMS and implementation of a flow control function. Ballasting time increased by 14.2% after installing the UV BWMS, and it increased by 20.4% with both its installation and implementation of a flow control function. If actual conditions are taken into account, ballasting time after installing the UV BWMS is estimated to increase by at least 30% compared with current ballasting time. Therefore, when concerned parties select a UV type BWMS, it is advisable for them to minimize ship operation losses from an increase in ballasting time by considering the capacity of the actual ballast pumps on board and the flow energy loss of the UV BWMS. Additionally, it is recommended that a BWMS with larger capacity, larger pipes, and pipes with inside coatings be used to minimize the increase in ballasting time after installation of the BWMS.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.7-13
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• 2006

Plastichouse cultivation for crops and vegetables in the winter has been widely popularized in Korea. In the vinylhouse Ultraviolet B penetration is lower than in the field, and so some problems, as plant overgrowth and outbreak of disease, occurred frequently. The effect of artificial supplement ultraviolet B $(UV-B:280{\sim}320nm)$ radiation on the physiological responses and yield of perilla (perilla frutescens) was investigated UV-B ray was radiated on perilla with the 10th leaf stage at the distance of 90, 120 and 150 cm from the plant canopy for 30 days after planting in the vinylhouse. The production of fresh perilla leaves was high in the order of plastic house, ambient+50% of supplemental UV-B, ambient ambient+100% of supplemental UV-B. Enhanced UV-B radiation affected the intensity of thirty-three proteins in 2-dimensional electrophoretic analysis of proteins and ten proteins out of them seemed to be responsive to UV-B : a protein was, ATP synthase CF1 alpha chain, down regulated and nine proteins (Chlorophyll a/b bindng protein type I, Chlorophyll a/b binding protein type II precursor, Photosystem I P700 chlorophyll a apoprotein A2, DNA recombination and repair protein recF, Galactinol synthase, S-adenosyl-L-methionine, Heat shock protein 21, Calcium-dependent protein kinase(CDPK)-like, Catalase) were up-regulated.

• Journal of Radiation Protection and Research
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• v.37 no.1
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• pp.50-55
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• 2012

To evaluate the ability of Dongchongxiacao ($Paecilomyces$ $japonica$) extract (PJE) to protect the skin from photodamage, the gross and microscopic changes in the skin of hairless mice and PJE-treated mice exposed chronically to ultraviolet (UV) were examined. The skin of the UV-irradiated mice showed characteristic signs of photoaging, such as deep wrinkles across the back. PJE-treated mice showed a significantly decreased wrinkling score. By the 22nd week, 88.9% (i.p. with saline) or 44.4% (topical administration with cream base) of the UV-irradiated mice developed at least one tumor. PJE delayed tumor onset significantly. PJE (i.p.) was also effective in reducing the occurrence of UV radiation-induced skin tumors and reduced the number of tumors per mouse. After 22 weeks of treatment, 80.0% (i.p.) and 75.0% (topical) of the mice treated with PJE were tumor-free. Tumor multiplicity was reduced by 96.2% (i.p.) in the PJE treated groups. It is noted that skin that is chronically exposed to UV is subject to photoaging and photocarcinogenesis and regular use of PJE would prevent these photodamaging effects of UV.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.14-27
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• 2020

Purpose: To overcome several drawbacks of chemically-crosslinked collagen membranes, modification processes such as ultraviolet (UV) crosslinking and the addition of biphasic calcium phosphate (BCP) to collagen membranes have been introduced. This study evaluated the efficacy and biocompatibility of BCP-supplemented UV-crosslinked collagen membrane for guided bone regeneration (GBR) in a rabbit calvarial model. Methods: Four circular bone defects (diameter, 8 mm) were created in the calvarium of 10 rabbits. Each defect was randomly allocated to one of the following groups: 1) the sham control group (spontaneous healing); 2) the M group (defect coverage with a BCP-supplemented UV-crosslinked collagen membrane and no graft material); 3) the BG (defects filled with BCP particles without membrane coverage); and 4) the BG+M group (defects filled with BCP particles and covered with a BCP-supplemented UV-crosslinked collagen membrane in a conventional GBR procedure). At 2 and 8 weeks, rabbits were sacrificed, and experimental defects were investigated histologically and by micro-computed tomography (micro-CT). Results: In both micro-CT and histometric analyses, the BG and BG+M groups at both 2 and 8 weeks showed significantly higher new bone formation than the control group. On micro-CT, the new bone volume of the BG+M group (48.39±5.47 ㎣) was larger than that of the BG group (38.71±2.24 ㎣, P=0.032) at 8 weeks. Histologically, greater new bone area was observed in the BG+M group than in the BG or M groups. BCP-supplemented UV-crosslinked collagen membrane did not cause an abnormal cellular reaction and was stable until 8 weeks. Conclusions: Enhanced new bone formation in GBR can be achieved by simultaneously using bone graft material and a BCP-supplemented UV-crosslinked collagen membrane, which showed high biocompatibility and resistance to degradation, making it a biocompatible alternative to chemically-crosslinked collagen membranes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4B
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• pp.441-447
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• 2008

Volatile organic compounds (VOCs) emitted from various industrial sources commonly consist of biodegradable chemicals and recalcitrant compounds. Therefore, it is not effective to employ a single method to treat such mixtures. In this study, a novel hybrid system coupled with a ultraviolet (UV) photolysis reactor and a biofilter in a series was developed and evaluated using toluene and TCE as model VOCs. When only TCE was applied to the UV reactor, greater than 99% of TCE was degraded and the concentration of soluble byproducts from photo-oxidation reaction increased significantly. However, the toluene and TCE mixture was not effectively degraded by the UV photo-oxidation standalone process. The hybrid system showed high toluene removal efficiencies, and TCE degradation at a low toluene/TCE ratio was improved by UV pretreatment. These findings indicated that the UV photo-oxidation were effective for TCE degradation when the concentration of toluene in the mixture was relatively low. A restively high toluene content in the mixture resulted in an inhibition of TCE degradation. Thus, chemical interactions in both photo-oxidation and biodegradation need to be carefully considered to enhance overall performance of the hybrid system.

• Analytical Science and Technology
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• v.27 no.3
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• pp.147-152
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• 2014

RUVIS(Reflective Ultraviolet Imaging System) is an effective equipment that detects the location of latent fingerprint at crime scene using short wavelength ultraviolet of 254 nm. In this study, the degree of DNA damage in biological samples was compared depending on the distance and time of processing using four commonly used RUVIS. 50% of DNA was damaged by treating 10 seconds at 10 cm distance in 3 types of RUVIS such as Police RUVIS, SIRCHIE mini light and SIRCHIE RUVIS. In addition, the degree of DNA damage was increased as the distance was closer and the treatment time was longer. It showed that short wavelength UV could cause DNA damage when used close to the samples at crime scene. Therefore, it was suggested to use RUVIS at a distance of at least 1 m. The degree of DNA damage was not significant by Polilight which used long wavelength ultraviolet of 350 nm. As a result, the choice and usage of which UV light and RUVIS were critical for detection of fingerprint and successful DNA typing.