In this study, (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate acrylate was synthesized by reacting (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate with acrylic acid to minimize hardening shrinkage and to improve heat resistance, which are known as disadvantages of photopolymers for 3D printing application. Urethane acrylate was synthesized by reacting 1,3,5-triazine-2,4,6-triamino alcohol, 2-hexylethyl acrylate, and isophorone diisocyanate in order to improve the mechanical properties without deteriorating the heat resistance. The physical properties before and after the synthesis of the acrylate and the mechanical properties when the urethane acrylate was applied were investigated. The reaction progress of the composite was examined by FTIR and 13C NMR. The heat deflection temperature, flexural strength, and surface hardness of the molding were measured. The curing behavior by Photo-DSC ultraviolet irradiation was also examined.

HYB(FRP Hybrid Bar) is composite structural material that combines reinforced bar and FRP. HYB has high elastic modulus and after-yield-hardening properties, despite its corrosion resistance and light weight. HYB under development has relatively stable corrosion durability. This study performs fundamental experiments for the long period UV exposed HYB, and carries out pull-out test for the freezing-thawing exposed specimens of ordinary reinforced bar, HYB, and UV exposed HYB. The effect of UV exposure and freezing-thawing did not affect the tensile property and strength of HYB. However, the bond strength reduction on the environment of accelerated corrosion should be considered in further study.

In this study, UV irradiation reactors were used to eliminate 4 types of volatile organic compounds (VOCs) in various experimental conditions. The 4 types of VOCs used include acetone (AC), chlorobenzene (CB), dichloromethane (DCM) and methylbenzene (MB). An ozone producing low-pressure mercury lamp that emits UV irradiance at 254 nm and 185 nm was used. The tested operating conditions included UV light intensity, inlet VOCs concentrations, empty bed retention time (EBRT), background gas and relative humidity (RH) of the gas. Firstly, higher UV light intensity is confirmed to have higher VOCs removal efficiency (RE). Higher inlet VOCs concentration will result in lower VOCs RE, and the decreasing trends of different VOCs are not identical. At the same inlet VOCs concentrations, increasing the EBRT will result in a rise in VOCs RE, but a further increase in EBRT will bring about less enhancement in RE. Moreover, UV irradiation in oxygen has the highest VOCs RE compared with that in air and nitrogen gas (N2), indicating that photolysis and photooxidation are both important. Finally, there was no increase the VOCs RE at the increase in RH. All the experimental results indicate that an identical set of operating conditions should be applied when the removal capacities of different VOCs according to the UV irradiation amount are compared.

This study was conducted to investigate the effect of ultraviolet light (UV-B) on plant growth and petal antioxidants of edible flower pansy (Viola × wittrochiana ‘Rose’ and ‘Yellow’, V. cornuta ‘Purple’). The plants were grown under white LED of 100 μmol·m-2·s-1 PPFD and treated by UV-B of 10, 20 and 30 minutes per day: UVB-10, UVB-20, and UVB-30 respectively. The plant growth was significantly inhibited as longer UV-B radiation exposure, even ‘Rose’ could not f lower under UVB-30. NPQ increase was observed in all cultivars with longer UV-B irradiation exposure. Also, anthocyanin in ‘purple’ and ‘Rose’ or carotenoid in ‘Yellow’ increased in the petals as longer UV-B radiation exposure. Unexpectedly the contents of total phenol and DPPH did not show the significance in UV-B treatments. In conclusion, the applicable UVB exposure to edible pansy in order to more accumulate antioxidants in petals would be in 20 minutes per day.

This study was conducted to investigate the effect of cold plasma combined with UV-C irradiation against Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes on lettuce. E. coli O157:H7, S. Typhimurium, and L. monocytogenes, corresponding to approximately 5.82, 5.09, 5.65 log CFU/ g, were inoculated on lettuce, respectively. Then, the lettuce was treated with cold plasma, UV-C and combination (cold plasma + UV-C), respectively. The treated lettuce was stored for 9 days at 4oC for microbiological analysis and sensory evaluation. Cold plasma reduced the populations of E. coli O157:H7, S. Typhimurium, and L. monocytogenes by 0.26, 0.65, and 0.93 log CFU/g, respectively. Each microorganism were reduced by 0.87, 0.88, and 1.14 log CFU/ g after UV-C treatment. And, the combined treatment that was treated by cold plasma after UV-C treatment reduced the populations of inoculated microorganisms by 1.44, 2.70, 1.62 log CFU/g, respectively. The all treatment significantly (p < 0.05) reduced the populations of all inoculated bacteria compared to untreated lettuce. UV-C combined with cold plasma was the most effective for reducing the pathogenic bacteria on lettuce, by showing log-reductions of ≥ 2.0 log CFU/g. All treatment was not significantly different until 6 day storage compared to control group in terms of appearance, texture and overall acceptability. Therefore, the combined treatment will be an effective intervention method to control the bacteria on lettuce.

The UV/chlorine process is a UV-based advanced oxidation process for removing various organic pollutants in water. The process is becoming increasingly popular because of its effectiveness in practice. It is important to the safe and efficient operation of a UV/chlorine process that the optimal operating conditions for both target removal objective and saving energy are determined. Treatment efficiency of target compounds in UV/chlorine process was mainly affected by pH and scavenging factor. In this study, kinetic based mathematical model considering water characteristics and electrical energy dose calculations model was developed to predict of treatment efficiency and optimal operating conditions. The model equation was validated for the UV/chlorine process at the laboratory scale and in pilot tests at water treatment plants.

본 연구에서는 환경 친화적 재료를 제조할 목적으로 자연계에 풍부한 bacteri al cellulose를 지지체로 하여 이온교환 특성이 있는 acrylic acid 단량체를 자외선 그라프트 중합법으로 고정시켰다. 이 중합체를 중금속 흡착제로서 막분리 hy brid시스템에 적용하기 위해 모델 용질로 Pb에 대한 흡착거동을 조사하였고 이에 대한 흡착 등온식 및 Benaissa model과 Kurniawan model 속도식을 적용하여 해석하였다.

A novel nanocomposite LDPE film with UV protective properties was developed for active packaging applications. Initially, undoped and Mn-doped TiO2 nanoparticles (NPs) were synthesized by the sol-gel method and the resulting particles were characterized. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed an agglomerated nature and spherical morphology. X-ray diffraction (XRD) studies indicated that all products were crystalline and in the form of rutile. The reflectance spectrum of undoped TiO2 NPs demonstrated a characteristic sharp edge at 410 nm. Subsequently, nanocomposite (NC) LDPE samples were prepared with the NPs by solvent precipitation followed by film casting. The optical and thermal properties of the NC samples were investigated. Incremental increases in Mn concentration from 0.25 mol % to 1.00 mol % were associated with progressive decreases in light transmission in the UV region. The melting and maximum decomposition temperatures of all NCs were 107 and 442-449 °C, respectively. The UV protective LDPE-based NC films exhibited superior photostability. Absorption in the FTIR spectra at 1716 and 1734 cm-1 changed after 4-wk exposure to UV for all film samples as a consequence of photodegradation. Finally, the photooxidation of perilla oil was assessed as an example of a UV protective packaging application. After 12 days, protection with 1.00 mol% Mn-doped TiO2-LDPE was associated with a gradual increase in PV, while protection with TiO2-LDPE was associated with a significant increase and protection with the control treatment was associated with a dramatic increase in PV. Hence, a 1.00 mol% Mn-doped TiO2-LDPE NC showed promise for UV shielding packaging applications.

Oxathiapiprolin은 병원균의 포자형성과 효모성장을 저해하여 노균병을 방제하는 piperidinyl thiazole isoxazoline 계열 살균제로 2015년 국내 사용등록이 요청된 신규약제이다. 본 연구에서는 oxathiapiprolin의 신규등록과 관련해 안전관리를 위한 공정시험법 마련이 요구되어 농산물 중 잔류분석법을 개발하였다. 농산물 중 oxathiapiprolin은 acetonitrile로 추출한 뒤 분배효율 향상을 위해 1 N sodium hydroxide (NaOH)를 이용해 염기성으로 조절하여 비해리상태로 만든 뒤 dichloromethane으로 액액분배하였으며 분배추출액은 silica SPE 카트리지로 정제한 뒤 HPLC-UVD로 분석하였다. 개발된 분석법의 검출한계(LOD) 및 정량한계(LOQ)는 각각 0.003, 0.01 mg/kg이었고, 대표농산물 5종(고추, 감귤, 감자, 대두, 현미) 중 oxathiapiprolin의 평균 회수율은 86.7-112.7%(상대표준편차, RSD ≤ 10%)으로 나타났다. 이는 잔류물 분석에 관한 CODEX 가이드라인 (CAC/GL 40)을 만족하는 것으로 확인되었다. 따라서 개발된 분석법은 국내외 유통 농산물 중 oxathiapiprolin의 안전평가를 위한 잔류량 적부 판정에 있어 공정시험법으로 사용되기에 적합할 것으로 판단된다.

본 연구에서는 역삼투막의 내오염성을 향상시키기 위해 실란 커플링제로 표 면 개질하여 steric hinderance를 일으키고 에폭시 코팅으로 친수성을 향상시키고자 하였다. 상용 역삼투막을 UV로 식각하여 표면을 활성화한 후 말단기가 다 른 실란 커플링제를 sol-gel 공법으로 표면 개질하고 에폭시를 이용하여 코팅하였다. 그 결과, 친수성 및 내오염성이 향상된 것을 확인하였고, FT-IR, SEM, XPS 를 통해 막의 특성을 분석하였다.

역삼투막은 해수의 담수화, 하수 및 폐수 재이용, 산업용수등의 다양한 용도로 널리 사용되고 있다. 하지만 미생물, 콜로이드물질, 스케일, 유기물 등 막의 오염으로 인해 전력비 및 교체비등 운영비가 증가되는 문제를 야기시킨다. 산업 용수 플랜트에서는 역삼투막의 주요 오염 중 하나인 바이오파울링을 저감시키기 위하여 일반적으로 사용하는 염소, 오존 등의 산화성살균제외 CMIT, DBNPA 등 비산화성 살균제도 사용하게 되는데 높은 약품비용로 운영비 증가의 원인이 되기도 한다. 본 연구는 파일럿플랜트를 이용하여 BWRO공정의 자외선 소독 전 처리의 효과검증을 약 1년간 실시하였다. 테스트결과 시기별로 차이가 발생하였 지만 역삼투막의 차압 증가속도를 감소시켜 향후 플랜트 적용 시 운영비 절감에 기여할 것으로 판단된다.

Disinfection of microorganisms using UV light is widely used in the field of water supply and wastewater treatment plant, In spite of high germicidal effect and relatively clean by-product, UV disinfection has fundamental defeat that is accumulation of fouling materials at the interface of water and lamp sleeve. Non-contact type of UV photoreactor which can avoid this fouling generation was developed and the experimental performance evaluation of the system was carried out in this study. Log inactivation rate of E. coli was selected as a disinfection index. The concentration of E. coli of second clarifier effluent was 8.2×101 - 8.2×103 colony per mL and was well inactivated by the non-contact type of UV photoreactor. Under the UV intensity condition of 2.1 - 2.5mW/cm2, E. coli removal rate was observed in the range of 54 - 95% when the HRT was increased from 10 to 52 seconds. Experimental results showed that log inactivation of E. coli was proportional to UV dosage and 200mJ/cm2 of UV dose is expected for the 2.0 log inactivation of E. coli from the second clarifier effluent. Between the two parameters of UV intensity and contact time which are consist of UV dose, UV intensity was 4 times more effective than contact time.s

The potential use of UV-TiO2 photocatalytic oxidation absorbent reactor in the removal of gaseous formaldehyde was studied. This study was conducted inside a bench-type circulation reactor chamber at ambient air conditions. PCO (Photocatalytic Oxidaion) degradation test for formaldehyde was done repeatedly and the average was reported. It was evident that photocatalytic oxidation was proven to be an effective method to control indoor air pollutants, like formaldehyde in indoor air. However, by-products are produced in the case of formaldehyde degradation also CO2, CO, H2O and formic acid are produced. These by-products can inhibit the active site of the photocatalyst. Thus, addition of adsorbent succeeding the PCO-TiO2, acts as a secondary treatment wherein produced by-products from the degradation and unreacted HCHO will adhere to the surface of the adsorbent. In this study, synthetic zeolite and activated carbon pellets were used to control of by-products of formaldehyde. PCOTiO2 degradation alone achieves 86% for a period of 60 minutes. Addition of adsorbent improves the removal efficiency achieving 90% and 96% using activated carbon pellet and zeolite, respectively.