• 한국환경과학회지
• /
• 제27권6호
• /
• pp.447-456
• /
• 2018

In this research, the target process was a modified type of a conventional aeration tank with four different influent feeding points and alternated aeration to obtain nitrogen removal. For more accurate switching of influent feeding, the process was operated under a designed control strategy based on monitoring of $NH_4-N$ and $NO_X-N$ concentrations in the tank. However, the strategy did have some limitations. For example, it was not sensitive to detecting the end of each reaction when losing the balance between nitrification and denitrification of each opposite part of biological tank. To overcome the limitations of the existing control strategy, a diagnosis-based control strategy was suggested in this research using the diagnosis results classified as normal (N), ammonia accumulation (AA) and nitrate accumulation (NA). Using the pre-designed rules for control actions, the aeration and volume of the aerated part of the reactor could be increased or decreased at a fixed mode time. In simulations of the suggested diagnosis-based control strategy, the $NH_4-N$ and $NO_X-N$ removal rates in the reactor were maintained at higher levels than those of the existing control strategy.

• KSBB Journal
• /
• 제6권1호
• /
• pp.35-43
• /
• 1991

The production of poly-$\beta$-hydroxybutyrate(PHB) from methanol by batch and fed-batch cultivations of Methylobacterium sp. GL-10 was studied. PHB accumulation was stimulated by the nutrients deficiency including, NH4+, SO42-, and K+. The nitrogen deficiency was the most critical factor for PHB accumulation. In batch cultivation, the maximum cell concentration and PHB content were 1.86g/l and 0.62g/l, respectively, with 1.0%(v/v) of methanol and 0.5g/1 of ammonium sulfate. The mass doubling time of Methylobacterum sp. GL-10 was in the range of 4-5 hrs. The cell growth and PHB accumulation were severely inhibited at the methanol concentration over than 2% (v/v). To overcome methanol Inhibition, constant feeding and intermittent feedillg fed-batch cultivations were adopted, using C/N molar ratio as a control factor. In constant feeding fed-batch process, cell concentration was increased up to 2.67g/1, and PHB yield was enhanced from 0.33 of batch culture to 0.53. The relatively low cell concentration was caused by methanol accumulated in culture broth at late growth phase. To prevent methanol accumulation and to maximize PHB production, DO-state intermittent fed-batch cultivation was attempted. The cell and PHB concentration was reached up to 4.55g/1 and 1.80g/1, respectively. It was possible to maintain methanol concentration low and also to feed nutrient of desired C/N molar ratio.

• 한국추진공학회지
• /
• 제13권4호
• /
• pp.1-8
• /
• 2009

킥모터의 정확한 성능 예측을 위해서 슬래그 적층량을 구하였다. 수치해석의 타당성을 확인하기 위해 KM 4호기의 질유량 시험값을 비교하였다. 비행 중 KM 슬래그 적층해석을 위해 각 시점별 내부유동 현상을 분석하였다. 알루미나 액적의 궤적을 통해 슬래그가 모터 내부에 적층되는 현상을 나타내었다. Fluent 6.3을 사용해서 유동현상 및 액적의 적층현상에 대한 수치해석을 수행하였다. 슬래그 적층량을 예측하기 위해 비행중의 가속도, 액적 출발점 위치, 액적의 크기 등에 대한 영향을 분석하였고 이를 고려하여 총 슬래그 양을 예측하였다.

• Journal of Plant Biotechnology
• /
• 제45권4호
• /
• pp.340-346
• /
• 2018

In this study, the effect of elicitors such as yeast extract (YE), methyl jasmonate (MeJA) and salicylic acid (SA) on the accumulation of eurycomanone in Eurycoma longifolia cell cultures were investigated. Suspension cells of E. longifolia was cultured in Murashige and Skoog (MS) medium supplemented with 30 g/L sucrose, 1.25 mg/L naphthaleneacetic acid (NAA) and 1 mg/L kinetin at a shaking speed of 120 rpm. Elicitors were added in the culture at different concentrations and times to stimulate eurycomanone accumulation in the Eurycoma longifolia cells. Eurycomanone content was determined by HPLC with a C18 column, flow rate of 0.8 mL/min, run time of 17.5 min, and a detector wavelength of 254 nm. The stationary phase was silica gel and the mobile phase was acetonitrile: $H_2O$. Non-elicited cells were used as the control. The study showed the effect of different elicitor concentrations, YE at 200 mg/L, MeJA at $20{\mu}M$ and SA at $20{\mu}M$ stimulated high production of eurycomanone. In which, treatment of $20{\mu}M$ MeJA after 4 days of culture resulted in the highest accumulation of this compound (17.36 mg/g dry weight), approximately 10-fold higher than that of untreated cells (1.70 mg/g dry weight).

• 한국지반공학회논문집
• /
• 제21권10호
• /
• pp.41-48
• /
• 2005

수평배수재가 설치된 준설매립지반의 중력에 의한 압밀 거동을 수평배수 자중압밀해석을 위하여 개발된 유한차분 프로그램을 이용하여 해석하였다. 수평배수재 단면의 크기와 수평배수재의 설치단면의 방향(수직/수평)이 대상지반의 압밀에 미치는 영향을 분석하였다. 또한 시공된 지반에서 발생 가능한 요인들, 즉 하부 무처리층의 존재, 그리고 수평배수재 단부에서의 수두적체 등이 압밀속도와 침하량에 미치는 영향도 분석하였다. 그 결과, 수평배수재의 단면적을 2배로 증가하여도 압밀 소요시간이 미량 감소하는데 그쳤으나, 수평배수재를 수직방향으로 설치한 경우 수평방향 설치시에 비하여 압밀소요 시간이 매우 감소하는 것으로 평가되었다. 해석결과로 부터 하부 무처리층의 영향이 처리 지반의 장기 침하에 미치는 영향이 크며, 배수재 단부에 발생하는 수두적체는 압밀시간 증가와 미진한 압밀효과를 초래하는 것을 정량적으로 알 수 있었다.

• KIEAE Journal
• /
• 제16권3호
• /
• pp.137-143
• /
• 2016

Purpose: Apartment housing should conduct a cyclic repair to keep and maintain the building performance since they are constructed. Therefore, the repair plan would be provided for long term period which explains the repair time, items and repair cost. Residents of apartment housing are responsible to pay for the repair activities. For repair cost, residents would reserve the money for repair little by little continuously until the required repair time because the repair cost takes a big burden for residents and lots of money a time. But, there is no systematic approach to provide the long term repair cost because it is no proper forecast of the repair cost to the upcoming repair time. In this study, it aimed at providing the monthly accumulation of the long term repair cost with the survey data in Seoul. Method: For these, the surveyed data are classified into 6 categories and number of data are 1,918. In addition, it developed the repair cost model for the 24 repair works and the cumulation function which is reflected with the each cost model. Result: This study are shown as follows : First, among the various estimation for the repair cost, the power function has a goodness of fit in statistics. Second, the monthly accumulation would be 12,840 won/household in size of $100,000m^2$ management area and $81.7won/m^2$ in size of the 1,000 household number during 40 years.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제4권1호
• /
• pp.51-57
• /
• 2000

Changes in the proline accumulation of ten-day-old seedlings of Vigna angularis in response to NaCl treatment were monitored. The proline content increased gradually both with an increase in the exposure time to salt stress and in a concentration-dependent manner. The increased proline accumulation was stronger in the shoots than in the roots. The salt stress by itself resulted in a significant inhibition of the chlorophyll content. Pre-treatment with proline before salinization lasting 48 h did not significantly affect the endogenous proline level in the roots, in contrast, a considerable increase of proline was observed in the shoots. The application of exogenous proline to the seedlings increased the endogenous proline content and improved the root and shoot growth under saline conditions. Detached leaves also exhibited an increased proline level in response to the applied NaCl, however, at a lower magnitude than in the intact seedlings. The proline alleviated the inhibitory effect of the NaCl in a concentration-dependent manner, thereby suggesting that salinity is a strong inducer of proline accumulation. In addition, abscisic acid eliminated the inhibitory effect of the salt salinity, thereby indicating a protective role on salinity stress and a regulatory role in proline synthesis. Accordingly, it would appear that proline may be involved in salt tolerance.

• 원예과학기술지
• /
• 제31권3호
• /
• pp.269-274
• /
• 2013

To further our understanding of sugar accumulation in 'Shiranuhi' mandarin [(C. unshiu ${\times}$ C. sinensis) ${\times}$ C. reticulate], we investigated the patterns of sugar uptake in juice sacs exposed to different concentrations of sucrose, fructose and glucose in vitro. Data was also collected on the change in weight and shape of the in vitro juice sacs over time. Soluble solids content, sugar content and acidity content were highest at 20% sucrose, fructose and glucose solution content; while fructose content was highest at 5% sucrose concentration. Furthermore, the juice sac's fresh weight was highest at 5% sucrose and lowest at 20% fructose content. The shape of the juice sacs also differed in different sugar concentration and type. Overall, sucrose, fructose and glucose content in juice sacs increased with the sugar concentration. These results suggest that sugar translocation into juice sacs is actively induced by high sugar concentration in the medium. Thus, it can be concluded that sugar and acid accumulation in juice sacs increased with sugar concentration in vitro culture.

• Fisheries and Aquatic Sciences
• /
• 제6권2호
• /
• pp.81-87
• /
• 2003

Experiments were carried out to investigate the accumulation and the histopathological changes in liver of juvenile rockfish, S. schlegeli, after sub-chronic dietary Cu (0, 50, 125, 250 and 500mg/kg) exposure for 60 days. Cu accumulation in liver was significantly increased with dietary exposure period and concentration for 60 days, and has a linear relation with dietary exposure days. After 60 days of Cu dietary exposure, the Cu concentration in the liver was $75.9\pm12.05,\;126.29\pm22.11\;and\;360.44\pm45.26\;{\mu}g/g$ dry weight and was approximately 11-fold, 18-fold and 51-fold higher than in the control diet group at 125, 250 and 500 mg/kg Cu diet group. The accumulation factors were increased with the dietary exposure period in liver of rockfish. In the primary exposed stage, the effect of hepatic tissue in the rockfish exposed to dietary Cu observed enlargement of hepatocytes nuclei, activity of hepatic cells and the swelling of hepatic cells. While exposed time and concentration were increased, the distinct granulation, irregular shape and necrosis of hepatic cells were observed. It was observed that granule degeneration and necrosis showed a part of cells in hepatic tissue after 60 days at 500 mg/kg.

• 대한방사선기술학회지:방사선기술과학
• /
• 제17권1호
• /
• pp.77-86
• /
• 1994

The bone scan reflects the metabolic reaction of bone to a disease process, whether neoplastic, traumatic or inflammatory. In normal bone tissue, the labeled diphosphate complexes accumulate in the perivascular fluid next to the marrow cavity at the interface between uncalcified and calcified bone matrix. HMDP has the most rapid plasma clearance among the commonly used diphosphonate followed by MDP and then HEDP. I have studied about bone scan time by use of $^{99m}Tc-MDP$, and got 336 images from 112 patients. The result obtained as follow; 1. Accumulation rate of $^{99m}Tc-MDP$ is higher than other age groups in below 30-year old group. 2. Accumulation rate, in 10year old group, is 75.85% on 120min. but other groups are most high on 180 min. 3. The density differants between bone and soft tissue increased with time. 4. Image contrast is good in younger group than old.