• Environmental Engineering Research
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• 제10권5호
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• pp.227-238
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• 2005

The characteristics of nitrogen removal by the free cell and the immobilized cell of R. capsulatus were investigated. Denitrification by R. capsulatus cells resulted in reduction of ORP with the rapid depletion of DO and the increase of pH. Without accumulation of nitrite, the removal efficiencies of ${NO_3}^-$-N for the free cell and the immobilized cell were 99.1 and 99.3%, respectively. During the three-month experiment of goldfish breeding equipped with a water-purification biofilter, the average values of pH and total cell numbers present in an aquarium were not significantly different between water-purification system and the control. The average concentrations of ${NH_4}^+$-N and ${PO_4}^{2-}$-P in water-purification system were relatively low, compared to that in the control. Goldfish died at $11^{th}$, $16^{th}$, $43^{rd}$, and $67^{th}$ days in the control, while goldfish died at $10^{th}$, $20^{th}$, and $39^{th}$ days in the water-purification system. On the days of goldfish's death, the total concentrations of nitrogenous compounds except for ${NO_2}^--N$ were higher than those on the other days of the experiment, especially with the concentrations of ${NH_4}^+$-N ranging from 7.4 to 13.5 mg/L. The water-purification system also showed the less turbidity of water with more active movement of goldfish than the control. PVA gel beads showed almost the full denitrifying ability even after the long-term experiment. As a result, the water-purification system was effective to remove nitrogenous compounds with better survival of goldfish.

• 한국물환경학회지
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• 제33권4호
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• pp.487-493
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• 2017

This study was conducted to propose measures of water quality management as the water criteria for waterscape facilities which have been highlighted as alternatives to wading pools in summer season was legislated. The number of public waterscape facilities has reached 290 sites in Gyeounggi province and 971 sites in South Korea in 2017. The water tank capacity of 80.3 % public waterscape facilities was less than $100m^3$. Facilities with disinfection system were only 6.5 % and facilities with filtration function were also very low at 6.9 %. Most of the waterscape facilities, about 93%, are expected to be vulnerable to complying with revised water quality criteria because they have to be disinfected by handling. Chlorine disinfectants, which are more persistent than ozone or ultraviolet sterilization methods, are more preferred. However, care should be taken when adding disinfectans because hypochlorous acid, which is an effective component of chlorine disinfectant, remains after the disinfection, but it is easily decomposed with time. For this study, ${\bigcirc}{\bigcirc}$ park floor fountain with a capacity of $63m^3$ was selected and the amount of free residual chlorine concentration was measured by injecting a certain amount of chlorine bleach. As a result, it took 5 hours to decrease from the water quality standard of 4 mg/L to 0.04 mg/L. If the waterscape facility is operated for 7 to 8 hours, the chlorine bleach should be re-injected after 5 hours. In addition, the problem of pH increase due to the input of chlorine disinfectant is expected, and the neutralization method using vinegar was proposed.

• 동의생리병리학회지
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• 제24권6호
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• pp.976-982
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• 2010

We studied to know the anti-inflammation effect on water extracts of Lophatheri Herba which was growing in every places in our country. We objected free radical scanvenger effect and nitrite eliminate effect of the Lophatheri Herba water extracts, and the cell viabillity, the effects of Lophatheri Herba water extracts on NO production, iNOS synthesis induced by LPS. Free radical scavenger effects were $27.91{\pm}0.12%$, $38.96{\pm}0.10%$, $46.22{\pm}0.15%$ depend on 0.5, 1.0, 2.0 mg/ml each dose of Lophatheri Herba water extracts. Nitrite eliminate effects were $9.86{\pm}0.3%$, $80.61{\pm}0.23%$, $97.62{\pm}0.56%$ in 0.1, 1.0, 2.0 mg/ml Lophatheri Herba water extracts on pH 1.2. NO production and iNOS synthesis induced by LPS were reduced in RAW 264.7 cell by Lophatheri Herba water extracts. As the above results, Lophatheri Herba water extracts have anti-inflammation effects via NO production decrease, iNOS synthesis decrease mechanism. So Lophatheri Herba water extracts will be used as the protection or treatment in chronic inflammation desease like a asthma, stomatitis etc.

• 한국식품과학회지
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• 제30권3호
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• pp.717-720
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• 1998

본 연구에서는 새로운 작물인 올방개를 이용한 가공식품 개발시 필요하고 참고가 될만한 몇가지 식품학적인 기초 성분들을 분석한 자료를 신속하게 제공하고자 하였다. 일반성분은 수분함량 79.40%, 조단백 1.74%, 조지방 0.06%, 조회분 1.10% 조섬유 0.60%, 탄수화물 17.71% 이었다. 유리당 조성은 sucrose가 8.58%, glucose가 1.64%, fructose가 1.58%로서 3가지 주요당이 올방개 착즙액의 고형분량중 약 66.0%를 차지하였으며, maltose도 미량 검출되었다. 칼륨의 함량이 408.57 mg%로 높게 나타났으며, 철분 및 망간은 각각 0.21 mg%, 0.08 mg%로 매우 적게 함유되어 있었다. 비타민 $B_1$은 $31.2\;{\mu}g/100\;g$ 정도 함유되어 있었고, 비타민 C는 미량이 검출되었다. 관능적인 특성은 향긋한 과일향과 단맛이 주된 풍미였으며, $100^{\circ}C$에서 20분 정도 끓여도 생시료와 거의 비슷한 정도의 아삭아삭함을 유지하였다.

• 대한기계학회논문집B
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• 제29권5호
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• pp.609-616
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• 2005

While the SIMPLE algorithm is most widely used for the simulations of flow phenomena that take place in the industrial equipments or the manufacturing processes, it is less adopted for the simulations of the free surface flow. Though the SIMPLE algorithm is free from the limitation of time step, the free surface behavior imposes the restriction on the time step. As a result, the explicit schemes are faster than the implicit scheme in terms of computation time when the same time step is applied to, since the implicit scheme includes the numerical method to solve the simultaneous equations in its procedure. If the computation time of SIMPLE algorithm can be reduced when it is applied to the unsteady free surface flow problems, the calculation can be carried out in the more stable way and, in the design process, the process variables can be controlled based on the more accurate data base. In this study, a modified SIMPLE algorithm is presented fur the free surface flow. The broken water column problem is adopted for the validation of the modified algorithm (MoSIMPLE) and for comparison to the conventional SIMPLE algorithm.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1784-1793
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• 2001

The flow fields around an elliptic cylinder of axis ratio AR=2 adjacent to a free surface were investigated experimentally using a water channel. The main objective is to understand the effect of the free surface on the flow structure in the near-wake. The flow fields were measured by varying the depth of cylinder submergence, for each experimental condition, 350 velocity fields were measured using a single-frame PIV system and ensemble-averaged to obtain the spatial distribution of turbulent statics. For small submergence depths a large-scale eddy structure was observed in the near-wake, causing a reverse flow near the free surface, downstream of the cylinder. As the depth of cylinder submergence was increased, the flow speed in the gap region between the upper surface of the cylinder and the free surface increased and formed a substantial jet flow. The general flow structure of the elliptic cylinder is similar to previous results for a circular cylinder submerged near to a free surface. However, the width of the wake and the angle of downward deflection of the shear layer developed from the lower surface of the elliptic cylinder are smaller tan those for a circular cylinder.

• 한국실내디자인학회논문집
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• 제25권4호
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• pp.113-124
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• 2016

This research examines domestic and oversea's barrier-free design guidelines provided exclusively for children and their implementations in the common spaces of the outpatient clinics in two pediatric rehabilitation hospitals in Seoul. Based on literature review, a checklist was developed to compare various barrier-free design guidelines in consideration of children's accessibility in space. In addition, four spatial areas in the outpatient clinics of the two hospitals were investigated based on the checklist. As a result, the domestic and Japanese guidelines were aiming primarily to all user groups regardless of ages. Whereas in other oversea's guidelines, a number of barrier-free design standards exclusive for children were found in the facility items such as handrail, sink, urine, toilet, water fountain, chair, table, shelve, and so on, throughout the indoor waiting and sanitary spaces. Concerning implementations, most of the items in the indoor passage, waiting, and sanitary spaces of the two hospitals were not sufficiently facilitated enough to meet with the barrier-free design standards exclusive for children. As such, it is recommended to review and improve the current domestic barrier-free design guideline to accommodate various physical and spatial needs of children in all age groups and regardless of disability types, in the design of a pediatric rehabilitation hospital in the future.

• Bulletin of the Korean Chemical Society
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• 제24권12호
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• pp.1742-1750
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• 2003

In order to characterize the hydrophobic parameters of N-acetyl amino acid amides in 1-octanol/water, a theoretical calculation was carried out using a solvation free energy density model. The hydrophobicity parameters of the molecules are obtained with the consideration of the solvation free energy over the solvent volume surrounding the solute, using a grid model. Our method can account for the solvent accessible surface area of the molecules according to conformational variations. Through a comparison of the hydrophobicity of our calculation and that of other experimental/theoretical works, the solvation free energy density model is proven to be a useful tool for the evaluation of the hydrophobicity of amino acids and peptides. In order to evaluate the solvation free energy density model as a method of calculating the activity of drugs using the hydrophobicity of its building blocks, the contracture of Bradykinin potentiating pentapeptide was also predicted from the hydrophobicity of each residue. The solvation free energy density model can be used to employ descriptors for the prediction of peptide activities in drug discovery, as well as to calculate the hydrophobicity of amino acids.

• 대한환경공학회지
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• 제28권1호
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• pp.26-33
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• 2006

본 연구에서는 염소와 모노클로라민을 이용하여 생물막이 제거되는 특성을 알아보았다. 염소와 모노클로라민을 0.5, 1.0, 2.0 mg/L의 농도로 잔류시킨 수돗물을 생물막이 형성되어 있는 모형 수도관에 연속적으로 공급하고, 관 표면으로부터 부착성 HPC와 biomass를 측정하였다. 염소는 생물막을 구성하는 미생물의 비활성화와 표면으로부터 생물막 matrix를 제거하는데 높은 효과를 나타낸 반면에 모노클로라민은 생물막 matrix를 제거하는데 염소보다 상대적으로 낮은 효율을 나타냈다. 특히 모노클로라민을 이용한 소독 처리에서는 세균과 EPS가 결합된 생물막 matrix가 관 표면으로부터 대부분 제거되지 않은 상태로 존재하였다. 비록 2.0 mg/L의 잔류염소가 생물막 제거에 높은 효과를 보였지만, 관 표면에는 여전히 낮은 수준(<10 $CFU/cm^2$ as 부착성 HPC, <5 ${\mu}g/cm^2$ as biomass)의 생물막이 잔류하고 있었다. 생물막의 제거 특성을 평가하는데 있어서 biomass의 측정이 효과적인 수단인 것으로 판단되었다.

• Macromolecular Research
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• 제13권2호
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• pp.135-140
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• 2005

Poly(vinyl alcohol) (PVA) membranes crosslinked with poly(acrylic acid-co-maleic acid) (PAM) were prepared to investigate the effect of aging on their morphology by swelling them for up to 7 days. PAM was used both as a crosslinking agent and as a donor of the hydrophilic-COOH group. A $30 wt\%$ weight loss of the dry membrane was observed in the swelling test after 6 days. The surface of the membrane was dramatically changed after the swelling test. The surface roughness of the PVA/PAM membrane was increased, as determined by atomic force microscopy (AFM). The swelling loosened the polymer structure, due to the release of the unreacted polymer and the decomposition of the ester bond, thereby resulting in an increase in the free volume capable of containing water molecules. The water molecules present in the form of free water were determined by differential scanning calorimetry (DSC). The fraction of free water increased with increasing swelling time. The swelling of the membrane may provide space for the transport of protons and increase the mobility of the protonic charge carriers. The proton conductivity of the membranes measured at T= 30 and $50^{\circ}C$ was in the range of $10^{-3} to 10^{-2} S/cm$, and slightly increased with increasing swelling time and temperature.