• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 2차
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• pp.192-199
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• 2010

This research produced internal model tester ($2.0m{\times}2.0m{\times}1.0m$) to evaluate the field application of Paju Unjeong District water recycling system for small streams eco-friendly river bed disparity method for the first time in Korea and conducted comparative analysis of the Paju Unjeong District water recycling system field test results and infiltration rate result of internal tests by each rainfall intensity following surface material. Infiltration rate result of internal tests concrete pavement by rainfall intensity following surface material, asphalt pavement, bentonite mate, stabilized soil construction and mixed soil construction manifested low infiltration rate. On the contrary, compaction soil, grassland and water permeable packaging materials resulted in significant amount of infiltration rate. As for the field permeability test results, they were manifested similar tendency as indoor permeability test results and they satisfied the standard for standard of water permeability of domestic disparity facility (less than $1.0{\times}10-7cm$/sec). As compaction rate increased, unconfined compression strength increased as well while coefficient of water permeability decreased.

• 한국환경과학회지
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• 제16권10호
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• pp.1197-1202
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• 2007

Adsorption experiments of binary mixed gases composed of acetone/methylethylketone (MEK), MEK/benzene, MEK/toluene, and benzene/toluene were carried out on activated carbon fixed-bed. The variations of equilibrium adsorption capacity according to type and fraction of binary gas were investigated. In case of binary gases composed of acetone/MEK and benzene/toluene, equilibrium adsorption capacities of MEK and toluene were increased according to the increase of fraction of MEK and toluene, but equilibrium adsorption capacities of acetone and benzene were decreased. In case of binary gases composed of MEK/benzene and MEK/toluene, equilibrium adsorption capacities of benzene and toluene were increased according to the increase of fraction of benzene and toluene, but equilibrium adsorption capacities of MEK was decreased.

• 한국지반환경공학회 논문집
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• 제16권3호
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• pp.35-39
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• 2015

Dowex 21K XLT 수지를 이용하여 산업폐수 내에 존재하는 금과 납-시안 착화합물에 대한 연속흡착 및 회수 특성을 조사하였다. 충전층에 충진된 Dowex 21K XLT 수지는 0.5mL/min의 유입유속에서 금-시안 착화합물을 520 bed volume까지 95% 이상 연속적으로 제거할 수 있지만, 납-시안 착화합물은 전혀 제거할 수 없었다. Dowex 21K XLT 수지에 흡착된 금-시안 착화합물은 HCl과 Acetone을 7:3의 비율로 섞은 혼합액을 탈착제로 이용하였을 때, 8 bed volume 내에서 96% 탈착되어졌다. 또한 두 번 재사용된 Dowex 21K XLT 수지의 금-시안 착화합물에 대한 bed volume이 490을 유지하여 향후 금 이온을 포함하고 있는 산업폐수 처리공정에 충분히 적용될 수 있을 것으로 판단된다.

• Current Research on Agriculture and Life Sciences
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• 제17권
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• pp.7-13
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• 1999

고추의 뿌리에 서식하고 있는 근권미생물을 30여종 분리하여 고추 검은 곰팡이병원균 A. alteranta에 길항하는 미생물을 분리한 결과 분리주 No. J-24 균주가 가장 길항력이 우수하였으며 Bacillus subtilis로 동정되었다. B. subtilis J-24는 검은곰팡이병균(Alternaria alternata)에 대해서는 생육저지 효과가 99%로 나타났으며, 그외 갯빛곰팡이병균(Botrytis cinerea), 역병균(Phytophthora capsici), 잘록병균(Pythium ultimum), 탄저병균(Colletotrichum gloeosporioides), 겹무늬병균(Stemphylium botryosum)에도 생육저지효과를 강하게 나타내었다. 고추 유묘의 생장활력은 미생물제제가 첨가된 상토가 일반 상토 보다 엽면적이 15%, 줄기길이가 12%, 뿌리길이가 12% 증가하였고 전체 건물중이 약 13% 증가하여 고추유묘의 생장활력이 증가되었다.

• Journal of Ecology and Environment
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• 제37권4호
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• pp.185-194
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• 2014

Seasonal monitoring was implemented to understand the influence of macrophyte bed structure on the composition and trophic interaction of aquatic organisms (algae, zooplankton, macro-invertebrate, and fish) in a shallow wetland (Upo Wetland, South Korea). Distinct division of the plant assemblage (reed zone and mixed plant zone) was observed. The reed zone was composed solely of Phragmites communis, whereas the mixed plant zone comprised a diverse macrophyte assemblage (Salvinia natans, Spirodela polyrhiza, Trapa japonica, Ceratophyllum demersum, and Hydrilla verticillata). Most of the aquatic organisms were more abundant in the mixed plant zone than in the reed zone, and this was positively associated with the seasonal development of macrophyte cover. Stable isotope analysis showed seasonal interactions among aquatic organisms. The majority of aquatic animal (zooplankton, Odonata, and Ephemeroptera) were dependent on epiphytic particulate organic matter (EPOM), and the dependence on EPOM gradually increased toward autumn. Interestingly, Lepomis macrochirus consumed Ephemeroptera and zooplankton in both macrophyte zones, but Micropterus salmoides depended on different food items in the reed zone and the mixed plant zone. Although, M. salmoides in the reed zone showed food utilization similar to L. macrochirus, it consumed Odonata or small L. macrochirus in the mixed plant zone. Based on these results, it appears that differences in the structure of the two macrophyte zones support different assemblages of aquatic organisms, strongly influencing the trophic interactions between the aquatic organisms.

• 환경위생공학
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• 제15권2호
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• pp.34-40
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• 2000

In the tungsten industry, molybdenum wire which used as the center supporter for coil shape tungsten wire was removed. Nitric acid dissolution method which used prevalently up to the present, takes nitric acid as major component and use noxious material such as sulfuric acid and hydrochloric acid remove molybdenum wire which used as center supporter by dissolve selectively within the range of no damage on tungsten wire. Mixed acid waste water occurred to the process were difficult to be decomposed by the conventional methords. This mixed acid waste water was treated by ozone, and It was obtained using possible by-product through the treatment waste water. For the three reactors with the same volume ; Blank reactor, Disturbance plate reactor, Packed-bed reactor ; the results were as follows : For the blank reactor COD removal efficiency in the pH = 4 (HRT : 6hr) was 28.5%, COD removal efficiency in the pH = 7 (HRT : 6hr) was 28.6%, and COD removal efficiency in the pH = 10 (HRT : 6hr) was 27.8%. For the disturbance plate reactor COD removal efficiency in the pH = 4 (HRT : 6Min.) was 86.5%, COD removal efficiency in the pH =7 (HRT : 6Min.) was 84.4%, and COD removal efficiency in the pH = 10 (HRT : 60Min.) was 86.8%. For the packed-bed reactor COD removal efficiency in the pH = 4 (HRT : 40Min.) was 76.0%, COD removal efficiency in the pH = 7 (HRT : 40Min.) was 81.3%, and COD removal efficiency in the pH = 10 (HRT : 40Min.) was 84.6%. After O3 treatment using possible by-product(Na2SO4) was 150g/ℓ.

• Ecology and Resilient Infrastructure
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• 제10권1호
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• pp.1-10
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• 2023

제방은 기본적으로 물이 넘치지 않도록 하기 위하여 조성되는 구조물이다. 개발된 제방보강 기술은 바이오폴리머와 골재를 혼합하여 제방의 붕괴로 발생되는 대규모 재난을 방지하기 위한 기술로 제방의 세굴 및 붕괴 등을 억제하는데 목적이 있다. 개발된 기술은 호안 사면 등에도 활용이 가능하지만 시공성이 수월하여 월류파괴에 대한 대응 기술로 적용하기 용이하다. 개발된 기술을 현장에 적용하기 위해서는 기술의 안전성을 확보해야 하므로 현장시범사업 등 실제 적용에 대한 연구가 필요하다. 하지만 월류 파괴는 현장에서 시범사업을 수행할 수 없으므로 본 연구에서는 실규모 실험을 통해 현장 적용성 연구를 수행하였다. 실규모실험은 안동에 위치한 하천실험센터에서 수행하였으며, 인위적인 월류를 통하여 제방 세굴 및 붕괴 상황을 검토하였다. 실험결과 개발기술이 월류파괴에 대해 대응 가능하고 붕괴를 억제할 수 있는 기술로의 실증을 수행하였다.

• 한국환경보건학회지
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• 제22권2호
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• pp.96-103
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• 1996

The objectives of this study were to examine the biodegradation of phenol using the anaerobic fluidized bed reactor(AFBR). Mixed microorganisms were selected from the anaerobic digestion tank, and could be adapted to high concentration of phenol by increasing the phenol concentration 600-3600 mg/l step by step. The results were summarized as follows: 1. The average removal efficiency of phenol was 90%, decreased by increasing concentration of phenol, and then a shock range was 1200~2400 ppm. 2. The production rate of biogas in overall limits was proportional to the concentration of influent phenol. 3. At steady state, compositions of gases were $CH_4$ 55~60%, $C0_2$ 34~43%, respectively. These were similar to that of the theoretical estimates. 4. The production rates of biogas and methane per the molarity of phenol removed were linearly increased, 56.45 l gas/mol-phenol and 29.20 l $CH_4/mol$-phenol. Using this biogas, the recoverable energy was 269.1 kcal/mol phenol. It was 120.2 kcal/g-COD, transforming into the chemical oxygen demand. 5. The bulk of microorganisms existed in suspended section of fluidized bed with type of biofilm and its concentration was 340 mg/g-media. In conclusion, the anaerobic treatment of pure phenol was possible and its removal efficiency, introducing the AFBR, was successful. Also toxic organic compound such as phenol was biodegradable and was recoverable as resource of energy.

• 대한간호학회지
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• 제54권2호
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• pp.139-150
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• 2024

Purpose: This study aimed to identify changes in sleep patterns and fatigue levels during consecutive night shifts among shift nurses and to determine the association between sleep parameters and increased fatigue levels during work. Methods: This prospective observational study employing ecological momentary assessments was conducted using data collected from 98 shift nurses working in Korean hospitals between June 2019 and February 2021. The sleep patterns were recorded using actigraphy. The participants reported their fatigue levels at the beginning and end of each night shift in real time via a mobile link. Linear mixed models were used for the analysis. Results: Nurses spent significantly less time in bed and had shorter sleep durations during consecutive night shifts than on off-duty days, whereas their wake times after sleep onset were much longer on off-duty days than on on-duty days. Fatigue levels were higher on the second and third night-shift days than on the first night-shift days. A shorter time spent in bed and asleep was associated with a greater increase in fatigue levels at the end of the shift than at the beginning. Conclusion: Nurses experience significant sleep deprivation during consecutive night shifts compared with off-duty days, and this sleep shortage is associated with a considerable increase in fatigue levels at the end of shifts. Nurse managers and administrators must ensure sufficient intershift recovery time during consecutive night shifts to increase the time spent in bed and sleeping.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.185-195
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• 2002

Previous research has shown that the flow of patients around departments of geriatric medicine and ex-patients in the community may be-modelled by the application of a mixed-exponential distribution. In this proper we considered a ave-compartment model using a continuous-time Markov process to describe the flow of patients. Using a M/ph/c queuing model, we present a way of optimizing the number of beds in order to maintain an acceptable delay probability a sufficiently low level. Finally, we constructed a Java computer simulation, using data from St George's Hospital, London.