This study investigated the effects of pectinase treatment and skin contact time on the quality characteristics of Dae-hong peach wine. Wine was produced with variations in enzyme treatment and skin contact time (1 hour, 2 hours, 1 day, 2 days, and until the completion of fermentation). Enzyme treatment increased the production yield by 6%, as well as ethanol and redness levels, compared to the non-treated control. Volatile components were higher when the skin contact time was 2 hours or 1 day. Results were compared according to enzyme treatment and skin contact time and found to be influenced by methanol and 3-methyl-1-butanol. Enzyme treatment effectively enhanced yields and volatile compound contents. However, skin contact should be concluded a day before 1 day to ensure compliance with methanol legislative requirements. Therefore, our findings show that enzymatic treatment with shorter skin contact time preserves the distinctive characteristics of Dae-hong peaches and ensures the production of safe and flavorful wine.

Radioactive products generated by long-term operation at NPP can become deposited on the surfaces of the system and equipment, leading to radiation exposure for workers during the decommissioning process. Chemical decontamination is one of the methods to reduce radiation exposure of workers, and there are HP CORD UV, CITROX, CAN-DECON. In the chemical decontamination process, organic acids are generally used, and representative organic acids include oxalic acid and citric acid. There are various methods for removing residual organic acid in decontamination liquid waste, such as using an oxidizing agent and an ion exchange methods. However, there is a problem in that oxidizing agent is used excessively or secondary wastes are generated in excess during organic waste treatment. However, when organic acid is decomposed using a UV lamp, the amount of secondary waste is reduced because it tis decomposed into CO2 and H2O. In this study, organic acid decomposition was evaluated as the contact time of the UV lamp. The experimental equipment consists of a UV reactor, a mixing tank, a circulation pump. The experimental conditions involved preparing 60 L of organic liquid waste containing oxalic acid, hydrogen peroxide and iron chloride. Test A was conducted using one UV reactor, and Test B was performed by connecting two UV reactors in series. As a result of the experiment, a decomposition rate of over 95% was shown after one hour for oxalic acid, and it was confirmed that the initial decomposition rate was faster as the contact time increases. Therefore, in order to increase the initial decomposition rate, it is necessary to increase the contact time of the UV lamp by connecting the UV reactors in series.

High voltage impulse (HVI) has been gained attention as an alternative technique that could control the CaCO3 scale problems encountered in water main, pipe, cooling tower and heat exchanger vessels. The aim of this study was to investigate the effect of electric field (E) and contact time (t) of HVI on reduction of Ca2+ concentration at two different temperatures of 25℃ and 60℃. A kinetic model on the effect of E and t was investigated too. As the E and t increased, the Ca2+ concentration decreased more than that of the control (= no HVI). The Ca2+ concentration decreased up to 81% at 15 kV/cm at 60℃, which was nearly 2 times greater than the control. With these experimental data-set of reduction of Ca2+ concentration under different E and t, the kinetic model was developed. The relationship between E and t required to reduce the concentration of Ca2+ by 30% was modeled at each temperature. The empirical model equations were; E0.83· t = 60.3 at 25℃ and E0.08· t = 1.1 at 60℃. These equations state the products of En and t is always constant, which means that the required contact time can be reduced in accordance with the increment of E and vice versa.

Electro-coagulation process has been gained an attention recently because it could overcome the membrane fouling problems in MBR(Membrane bio-reactor). Effect of the key operational parameters in electro-coagulation, current density(ρ i) and contact time(t) on membrane fouling reduction was investigated in this study. A kinetic model for ρi and t required to reduce the membrane fouling was suggested under different MLSS(mixed liquor suspended solids) concentration. Total 48 batch type experiments of electro-coagulations under different sets of current densities(2.5, 6, 12 and 24 A/m2), contact times(0, 2, 6 and 12 hr) and MLSS concentration(4500, 6500 and 8500mg/L) were carried out. After each electro-coagulation under different conditions, a series of membrane filtration was performed to get information on how much of membrane fouling was reduced. The membrane fouling decreased as the ρi and t increased but as MLSS decreased. Total fouling resistances, Rt (=Rc+Rf) were calculated and compared to those of the controls (Ro), which were obtained from the experiments without electro-coagulation. A kinetic approach for the fouling reduction rate (Rt/Ro) was carried out and three equations under different MLSS concentration were suggested: i) pi0.39t = 3.5 (MLSS=4500 mg/L), ii) pi0.46t = 7.0 (MLSS=6500 mg/L), iii) pi0.74t = 10.5 (MLSS=8500 mg/L). These equations state that the product of ρi and t needed to reduce the fouling in certain amounts (in this study, 10% of fouling reduction) is always constant.

본 연구는 기구등에 오염된 E. coli와 S. aureus를 제어 하기 위해 이산화염소의 농도별 접촉시간에 따른 살균소 독력을 평가하여 살균예측모델을 개발하였다. E. coli의 경우 초기균수가 9.13 log CFU/mL이었고, 청정조건에서 5 ppm으로 1분, 3분, 5분 처리한 결과 각각 0.04, 0.07, 0.10 log CFU/mL의 감소값을 나타내었다. 20 ppm을 처리한 결 과 각각 0.74, 0.79, 0.84 log CFU/mL의 감소값을 나타내었다. 또한 CCD에 의한 최대농도 35 ppm으로 처리한 결과 각각 2.49, 2.70, 3.65 log CFU/mL의 감소값을 나타내었다. S. aureus의 경우 초기균수가 8.70 log CFU/mL이었고, 청정조건에서 5 ppm으로 1분, 3분, 5분 처리한 결과 각각 0.14, 0.28, 0.36 log CFU/mL의 감소값을 나타내었다. 20 ppm을 처리한 결과 각각 0.66, 0.79, 0.90 log CFU/mL의 감소값을 나타내었다. 또한 CCD에 의한 최대농도 35 ppm 으로 처리한 결과 각각 4.59, 5.25, 5.81 log CFU/mL의 감소값을 나타내었다. 따라서 이산화염소의 살균소독력 평 가결과는 E. coli와 S. aureus에 대하여 식품의약품안전처 살균소독력 기준에 모두 만족하는 것으로 나타났다. 살균 예측모델의 경우, R2값이 모두 0.98 이상으로 두 균주에 대해 모두 높은 적합성을 보였다. 본 연구에서 개발된 이산화염소의 살균예측모델을 식품산업 적용을 위한 기초자 료로 활용함으로써 E. coli와 S. aureus를 적절한 농도와 접촉시간으로 제어할 수 있을 것으로 사료된다.

Recently EC-MBR (Elctrocoagulation - Membrane Bio Reactor) has been suggested as one of alternative processes to overcome membrane fouling problems. Most important operational parameters in the EC-MBR are known to current density and contact time. Their effect on membrane filtration performances has been reported well, however, quantitative interrelationship between both parameters not been investigated yet. The purpose of this study is to give a kinetic model suggesting the current density and the contact time required to reduce the membrane fouling. The 4 different set of current densities (2.5, 6, 12 and 24 A/m2) and contact times (0, 2, 6 and 12 hr) were selected as operational parameters. After each electro-coagulation under the 16 different conditions, a series of membrane filtration was carried out. The membrane fouling decreased as the current density and contact time increased, Total fouling resistances under different conditions, Rt(=Rc+Rf) were calculated and compared to those of the controls (R0), which were calculated from the data of experiments without electro-coagulation. A kinetic approach for the fouling reduction rate (Rt / R0) was carried out and the equation ρi0.46t=7.0 was obtained, which means that the product of current density and the contact time needed to reduce the fouling in certain amounts (in this study, 10% of fouling reduction) is always constant.

목 적: 1일 착용용 소프트 콘택트렌즈의 가파르게 처방된 정도에 따른 각막굴절력의 변화, 눈물막 파괴 시간의 변화, 안압의 변화와 상관관계를 알아보고자 하였다. 방 법: 대학생 24명(48안)을 대상으로 1일착용 렌즈를 8시간 착용시켜 8시간 경과 후 렌즈를 제거하고 각막굴절력, 눈물막 파괴시간 그리고 안압 측정을 시행하여 콘택트렌즈 착용전과 비교하였다. 결 과: 가파른 피팅을 함에 따라 각막굴절력은 +0.29±0.06 D 증가(t=-12.62, p<0.05)하였으며, 눈물 띠 파괴시간(TBUT)은 –1.26±2.02sec 감소(t=5.04, p<0.05)하였으며 안압은 –2.19±2.15mmHg 감소 (t=6.4, p<0.05)하였다. 가파른 피팅 정도에 따른 각막의 굴절력과의 상관관계(r=-0.98)는 강한 음의 상관 관계를 가졌으며. TBUT와의 상관관계(r=-0.26)는 약한 음의 상관관계를 가졌으나 안압(r=-0.07)과는 상관 관계가 없었다. 결 론: 각막의 곡률반경에 비하여 소프트 콘택트렌즈의 곡률반경이 0.3mm 이상 가파른 피팅되어 8시 간 착용했을 때, 각막굴절력의 변화에 대한 강한 상관관계가 있으므로 소프트 콘택트렌즈 처방 시 가파른 피 팅이 되지 않도록 유의해야 한다.

Purpose: This study was to assess the influence of silicone hydrogel contact lenses wearing time on corneal higher-order aberrations (HOAs), visual performance, and subjective ocular symptoms. Methods: Thirty subjects took part in this study. Subjects were fitted with silicone hydrogel contact lenses (Biofinity). Best-corrected visual acuity (VA) at two contrast levels (100% and 10%) and best-corrected contrast sensitivity (CS) for four spatial frequencies (3, 6, 12, and 18 cycles per degree) were measured under photopic and mesopic conditions. Corneal HOAs were measured with 4-mm and 6-mm pupils using Wavefront Analyzer. All measurements were performed respectively after 2 hours and 9 hours wear with the silicone hydrogel lenses during a day. Subjects were asked by a study examiner to complete the questionnaire for contact lens-related subjective ocular symptoms. Results: Data for this study were employed for fifty-four eyes (27 subjects; 14 females, 13 males) and the subjects were 24.30 ± 2.96 years. For the subjects, current or previous experience with contact lenses was 23 subjects and non-experience with contact lenses was 4 subjects. Regarding visual quality under photopic and mesopic conditions, there was no statistically significant difference in high contrast and low contrast visual acuity as well as contrast sensitivity between 2 hours and 9 hours wear. For corneal HOAs, we also did not find any significant changes in total HOAs, third-order, fourth-order, coma, and spherical aberration for both 4-mm and 6-mm pupils between the two wearing time. In the relative frequency of contact lens-related subjective ocular symptoms, there were statistically differences in discomfort, dryness, and closing eyes between 2 hours and 9 hours wear within the brand (p=0.031, p=0.001, and p=0.031, respectively) (after 9 hours of the lens wear, discomfort (52%), dryness (74%), and closing eyes (56%)); however, there were no significant differences in changeable vision and removing lenses between the two wearing time. Conclusions: Silicone hydrogel contact lenses used this study do not reduce optical quality of the eye and visual quality after nine hours of the contact lens wear during a day. However, the majority of soft contact lens wearers still encounter clinically significant ocular symptoms including discomfort and dryness with the silicone hydrogel lenses.

Purpose: Non-invasive tear break up time (NITBUT) is a test commonly used by clinicians to measure the stability of the tear film. This study aims to compare the NITBUT of the Bausch and Lomb Biotrue Oneday (BT) Daily Disposable contact lenses against 3 other commercially available daily disposable lenses to see if BT can provide a more stable pre-lens tear film over the other 3 types of lenses at 12 hours of lens wear. Methods: Twelve existing contact lens wearers were recruited to wear 4 types of contact lenses each for a day of at least 12 hours. Other than BT, the other 3 test lenses were the daily disposable lenses made of etafilcon A (AV), narafilcon A (TE) and delefilcon A (DT1) materials. Each subject was assigned the lenses without knowing the brand of the lenses. Baseline NITBUT was first measured with no lens in the eye and pre-lens NITBUT was measured again at 12 hours after the lenses were worn. The NITBUT was measured using Oculus Keratograph 5M. This instrument measures the NITBUT objectively using infrared illumination which is invisible to the human eye and can prevent glare or bright light irritation during examination. Results: NITBUT was provided by the instrument as “first break” and “average break” values. In this study, the first break value was analyzed because that was the time when the break-up of tears was first detected by the instrument, and that matches with what the clinicians normally do in measuring NITBUT. The NITBUT for the nesofilcon A lens (BT) was longer than that for all the other 3 lens types in 10 out of the 12 subjects (83%). The mean TBUT for BT, AV, TE, DT1 was respectively 17.9 ± 4.3 sec, 9.5 ± 3.3 sec, 8.3 ± 5.9 sec and 8.8 ± 3.6 sec. Not only is the difference in NITBUT statistically significant (p<0.05, paired t-test – nesofilcon A (BT) Vs each of the 3 lens types), but also the NITBUT for BT is about double than that for all the other 3 types of lenses. Conclusion: The NITBUT for the nesofilcon A lens (BT) measured at 12 hours was about double than that for the other 3 lens types and the difference was statistically significant. The results suggested that the Biotrue Oneday provides a more stable pre-lens tear film than the other 3 types of daily disposable lenses at 12 hours of lens wear.

목적: 공기 중에서 플라즈마 처리가 된 상용 불화규소 아크릴레이트 RGP 콘택트렌즈(Boston XO)의 분위기와 유지 시간에 따른 표면 성분 및 습윤성의 변화를 연구하였다. 방 법: 렌즈는 진공, 공기, 물 등의 분위기로 보관했으며, X-선광전자분광분석기(XPS)로 성분과 화학결합을, 접촉각으로 습윤성의 변화를 측정하여 평가하였다. 결과: RGP 콘택트렌즈에 플라즈마 처리를 하면 렌즈 표면에 친수성기(C-O, O-C=O, Si-O)의 증가로 물에 대한 접촉각이 감소하여 표면의 습윤성이 증진되었으나, 모든 분위기에서 시간이 경과함에 따라 친수 성기가 감소하면서 접촉각이 증가하였다. 물 분위기에서는 렌즈 표면에 탄소 및 실리콘과 결합한 산소가 급격히 감소하면서 접촉각이 다시 증가하였다. 결론: 플라즈마 처리된 RGP 콘택트렌즈의 표면이 수분과 접촉하면, 산소가 급격히 감소하고 습윤성이 저하된다.

The bactericidal efficacy of three common sanitizers (100 or 200 ppm of sodium hypochlorite, 100or 200 ppm of n-alkyl(C12-C18)benzyldimethyl chloride, and 50 or 100 ppm of peroxyacetic acid) against Escherichia coli ATCC 10536 and Staphylococcus aureus ATCC 6538 was studied using the suspension test method at various exposure temperatures (4~40℃) and times(1~60min) under both dirty and clean conditions, respectively. During the suspension tests, sodium hypochlorite (200 ppm) showed higher bactericidal activity than the other sanitizers under clean conditions, with 5 log reductions against E. coli as well as S. aureus in the first 1 min of treatments at 4℃. However,the efficacy of sodium hypochlorite decreased markedly under dirty conditions due to its susceptibility to interfering substances. The efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride increased considerable as the exposure temperature and time increased. The bactericidal efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride might be less effective on low temperature, however, the longer time the sanitizer is in contact, the more effective the sanitization effect. Treatment with peroxyacetic acid (100 ppm) showed at least 5 log reduction against E. coli and S. aureus for 5min at 4℃ under both clean and dirty conditions. The efficacy of the peroxyacetic acid was not much altered by interfering substances and affected by changes in temperature or time.

본 연구에서는 청수 포도의 양조 특성에 미치는 세포벽 분해효소와 침용 처리의 효과를 조사하였다. 착즙의 용이 성은 세포벽분해효소 처리와 침용처리에서 우수하였으며, 착즙액의 방향은 5일간 침용처리 후 압착한 것이 가장 우수 하였다. 또한 착즙수율도 대조구에 비하여 세포벽분해효소 와 침용처리에서 크게 증가하는 것으로 나타났다. pH와 총산, 가용성고형물은 처리간에 큰 차이가 없었으며, pH는 3.1-3.4, 총산은 0.5～0.6%, 가용성고형물은 6.7～7.1 °Brix 의 범위를 나타내었다. 알코올 함량은 세포벽분해효소 처 리구가 13.3% 으로 가장 높았으며, 침용처리구는 상대적으 로 알코올 함량이 낮은 특징을 보였다. 총 폴리페놀 함량은 침용처리 기간이 길어질수록 증가하는 경향이었으며, 10일 간 침용처리시 306.4 mg/L로서 가장 높은 값을 나타내었다. 청수와인의 주요 유기산은 사과산과 주석산이었으며, 구연 산, 호박산 및 젖산도 검출되었다. 본 연구에서 세포벽분해 효소와 침용처리는 청수와인 제조에 있어서 착즙의 용이성 을 더 좋게 하며, 착즙수율이나 휘발성성분을 증가시키는 것으로 나타났다.