• Title/Summary/Keyword: Co-flow

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Geochemical Characteristics of Groundwater during the Constant and Step-drawdown Pumping Tests at the River Bank Filtration Site (장기 및 단계 양수시험 시 강변여과 지하수의 수질변화 특성)

  • Kim, Gyoobum;Shin, Seonho;Kim, Byungwoo;Park, Joonhyung
    • Journal of the Korean GEO-environmental Society
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    • v.14 no.8
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    • pp.11-21
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    • 2013
  • In-situ test to find the change of $Fe^{2+}$ and $Mn^{2+}$ concentrations and ion contents in groundwater was conducted during two pumping tests at the riverbank filtration site, where is the riverine area of the Nakdong River in Changnyeong-Gun. Groundwater was sampled at one pumping well and 10 monitoring wells during a 5 steps drawdown pumping test with the rates from $500m^3/day$ to $900m^3/day$ and a constant pumping test with $800m^3/day$. The change in ion concentration of groundwater was more remarkable during a step drawdown pumping test than a constant pumping test. Especially, the decrease in $Fe^{2+}$ and $Mn^{2+}$ concentrations was distinct in a step drawdown pumping test and it happens predominantly along the direction that the radius of pumping influence was small due to a good aquifer connectivity to a pumping position. The precipitation and the oxidation of iron and manganese were caused by an air inflow and a disturbance in groundwater flow due to an abrupt change in pumping rate. The pumping rate and spatial distribution of an aquifer around a pumping well need to be considered as an important factor for the development of in-situ iron and manganese treatment technology.

Design of Traffic Control Scheme for Supporting the Fairness of Downstream in Ethernet-PON (이더넷 기반 광가입자망에서 공평성 보장을 위한 하향 트래픽 제어 기법 설계)

  • Han Kyeong-Eun;Park Hyuk-Gu;Yoo Kyoung-Min;Kang Byung-Chang;Kim Young-Chon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.5 s.347
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    • pp.84-93
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    • 2006
  • Ethernet-PON is an emerging access network technology that provides a low-cost method of deploying optical access lines between OLT and ONUs. It has a point-to-multipoint and multipoint-to-point architecture in downstream and upstream direction, respectively. Therefore, downstream packets are broadcast from an OLT toward all ONUs sithout collision. On the other hand, since alt ONUs share a common channel, the collision may be occurred for the upstream transmission. Therefore, earlier efforts on Ethernet-PON have been concentrated on an upstream MAC protocol to avoid collision. But it is needed to control downstream traffic in practical access network, where the network provider limits available bandwidth according to the number of users. In this paper, we propose a traffic control scheme for supporting the fairness of the downstream bandwidth. The objective of this algorithm is to guarantee the fairness of ONUs while maintaining good performance. In order to do this, we define the service probability that considers the past traffic information for downstream, the number of tokens and the relative size of negotiated bandwidth. We develop the simulation model for Ethernet-PON to evaluate the rate-limiting algorithm by using AWESIM. Some results are evaluated and analyzed in terms of defined fairness factor, delay and dropping rate under various scenario.

Case Study on the Instability of the Slopes in Unsaturated Residual Soils Considering the Rainfall Characteristics (강우특성을 고려한 불포화 잔적토 비탈면의 붕괴사례 연구)

  • Nam, Samheon;Lee, Younghuy;Oh, Seboong
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.1
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    • pp.45-53
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    • 2015
  • This study has obtained Soil Water Retention Curve (SWRC) of the unsaturated soil from the volumetric pressure plate extractor test and the triaxial compression tests was also conducted. By using the rainfall data measured in the site the seepage analysis of unsteady flow was performed with the program of SEEP/W in Geostudio 2007 and stability of the slope was analyzed with SLOPE/W program. Results of analyses show that shear strength of the unsaturated soil increases with the increase of matric suction. And it was also found that the net volumetric stress and the apparent cohesion increased with the matric suction. The seepage analysis of rainfall represents that the increasing rate of negative pore pressure at the zone of large negative pore pressure is appeared to be high even though lower rainfall intensity, but this tendency declines with ground depth. The stability analysis of slope was carried out for the actual plane of failure with the data representing the field condition. The factor of safety thus calculated was about unity (1.0) or just below, which means that the adopted method of analysis is in good agreement with the field condition.

Validation of Method Determining Coixol in Coix lachryma-jobi var. ma-yuen Roots Extract (율무근 추출물의 Coixol 성분 분석법 검증)

  • Kwon, Jin Gwan;Seo, Changon;Choi, Yun-Hyeok;Choi, Chun Whan;Kim, Jin Kyu;Jeong, Wonsik;Lee, Ji Eun;O, Kyeong Hee;Hong, Seong Su
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.8
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    • pp.952-956
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    • 2017
  • An high performance liquid chromatography (HPLC) analysis method was developed for standard determination of coixol as a functional cosmetic material in Coix lachryma-jobi var. ma-yuen roots extract. HPLC was performed on a $C_{18}$ Unison US column ($4.6{\times}250mm$, $5{\mu}m$ column) using a gradient elution of 0.1% (v/v) trifluoroacetic acid and acetonitrile at a flow rate of 1.0 mL/min at $30^{\circ}C$. The analyte was detected at 290 nm. The HPLC method was validated in accordance with the International Conference on Harmonization guideline of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limit of detection and quantitation were 0.07 and 0.25 mg/mL, respectively. Calibration curves showed good linearity ($R^2$>0.9995), and the precision of analysis was satisfied (less than 0.29%). Recoveries of quantified compounds ranged from 98.36 to 100.30%. This result indicates that the established HPLC method is very useful for the determination of a marker compound in C. lachryma-jobi var. ma-yuen roots extracts.

The Effect of Skewness of Nonlinear Waves on the Transmission Rate through a Porous Wave Breaker (파형의 왜도가 투과성 방파제 투과율에 미치는 영향)

  • Cho, Yong Jun;Kang, Yoon Koo
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.6
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    • pp.369-381
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    • 2017
  • It has been presumed that highly nonlinear skewed waves frequently observed in a surf zone could significantly influence the transmission behaviour via a porous wave breaker due to its larger inertia force than its nonlinear counterparts of zero skewness [Cnoidal waves]. In this study, in order to confirm this perception, a numerical simulation has been implemented for 6 waves the skewness of that range from 1.02 to 1.032. A numerical simulation are based on the Tool Box called as the ihFoam that has its roots on the OpenFoam. Skewed waves are guided by the shoal of 1:30 slope, and the flow in the porous media are analyzed by adding the additional damping term into the RANS (Reynolds Averaged Navier-Stokes equation). Numerical results show that the highly nonlinear skewed waves are of higher transmitted ratio than its counterparts due to its stronger inertia force. In this study, in order to see whether or not the damping at the porous structure has an effect on the wave celerity, we also derived the dispersive relationships of Nonlinear Shallow Water Eq. [NSW] with damping at the porous structure being accounted. The newly derived dispersive relationships shows that the phase lag between the damping friction and the free surface elevation due to waves significantly influence the wave celerity.

Process Simulation and Economic Feasibility of Upgraded Biooil Production Plant from Sawdust (톱밥으로부터 생산되는 개질 바이오오일 생산공장의 공정모사 및 경제성 분석)

  • Oh, Chang-Ho;Lim, Young-Il
    • Korean Chemical Engineering Research
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    • v.56 no.4
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    • pp.496-523
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    • 2018
  • The objective of this study is to evaluate the economic feasibility of two fast pyrolysis and biooil upgrading (FPBU) plants including feed drying, fast pyrolysis by fluidized-bed, biooil recovery, hydro-processing for biooil upgrading, electricity generation, and wastewater treatment. The two FPBU plants are Case 1 of an FPBU plant with steam methane reforming (SMR) for $H_2$ generation (FPBU-HG, 20% yield), and Case 2 of an FPBU with external $H_2$ supply (FPBUEH, 25% yield). The process flow diagrams (PFDs) for the two plants were constructed, and the mass and energy balances were calculated, using a commercial process simulator (ASPEN Plus). A four-level economic potential approach (4-level EP) was used for techno-economic analysis (TEA) under the assumption of sawdust 100 t//d containing 40% water, 30% equity, capital expenditure equal to the equity, $H_2$ price of $1050/ton, and hydrocarbon yield from dried sawdust equal to 20 and 25 % for Case 1 and 2, respectively. TCI (total capital investment), TPC (total production cost), ASR (annual sales revenue), and MFSP (minimum fuel selling price) of Case 1 were $22.2 million, $3.98 million/yr, $4.64 million/yr, and $1.56/l, respectively. Those of Case 2 were $16.1 million, $5.20 million/yr, $5.55 million/yr, and $1.18/l, respectively. Both ROI (return on investment) and PBP (payback period) of Case 1(FPBU-HG) and Case 2(FPBU-EH) were the almost same. If the plant capacity increases into 1,500 t/d for Case 1 and Case 2, ROI would be improved into 15%/yr.

Three-Dimensional Limit Equilibrium Stability Analysis of the Irregularly Shaped Excavation Comer with Skew Soil Nailing System

  • Kim, Hong Taek;Par
    • Geotechnical Engineering
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    • v.14 no.3
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    • pp.73-94
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    • 1998
  • In the present study, a method of the three-dimensional limit equilibrium stability analysis of shape of the potential failure wedge for the concave-shaped excavation corner is assumed on the basis of the results of the FLACSU program analysis. Estimation of the three-dimensional seepage forces expected to act on the failure wedge is made by solving the three-dimensional continuity equation of flow with appropriate boundary conditions. By using the proposed method of three-dimensional stability analysis of the concave-shaped excavation corner, a parametric study is performed to examine the reinforcement effect of skew soil nailing system, range of the efficient skew angles and seepage effect on the overall stability. Also examined is the effect of an existence of the right-angled excavation corner on three-dimensional deflection behaviors of the convex-shaped skew soil nailing walls. The results of analyses of the convexshaped excavation corner with skew soil nailing system is further included to illustrate the effects of various design parameters for typical patterns of skew nails reinforcement system.

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Influence of Superplasticizers on Fluidity and Compressive Strength of Alkali Activated Slag Mortar (유동화제가 알칼리 활성 슬래그 모르타르의 유동 특성 및 압축 강도에 미치는 영향)

  • Kim, Dae-Wang;Oh, Sang-Hyuk;Lee, Kwang-Myong
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.1
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    • pp.33-40
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    • 2013
  • The cement industry brought very severe environment problems with massive carbon dioxide during its production. To solve this problem, attempts on Alkali-Activated Slag (AAS) concrete that perfectly substitutes industrial by-products such as ground granulated blast furnace slag (GGBFS) for cement are being actively made. AAS concrete is possible to have high strength development at room temperature, however, it is difficult to ensure the working time due to the fast setting time and the loss of workabillity because of the alkali reaction. In this study, the early age properties of alkali activated slag mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The water-binder ratio (W/B) was fixed at 0.35 and sodium hydroxide and waterglass as alkali activator was used. The compressive strength, the flow and the ultrasonic pulse velocity were measured according to the type of superplasticisers, which were naphthalene(N), lignin(L), melamine(M) and PC(P), up to a maximum of 2 percent by the mass of GGBFS. The results showed that adding melamine type of superplasticizer improved the fluidity of AAS mortar without decreasing the compressive strength, while naphthalene and polycarbonate type of superplasticizer had little effect on the fluidity of AAS mortar.

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Effects of UV Sterilization on Quality of Acer mono Sap (자외선 살균이 고로쇠 수액의 품질에 미치는 영향)

  • Choe, Su Bin;Han, Sang Jin;Han, Ouk Hee;Kim, Hak Su;Kang, Sung Tae
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.1
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    • pp.148-152
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    • 2013
  • An ultraviolet (UV) sterilization system was developed to decrease the number of microorganisms in filtered Acer mono sap (FAS). The Acer mono sap (AS) was passed through 18 strips of PTA fluoroplastic tubing with 30 UV lamps (total 1,170 W). During passage, the AS was effectively exposed to the UV rays. The total bacteria, coliform group and fungi were sterilized at a flow rate ranging from 852 to 1,358 mL/min and a UV power higher than 156 W. Although the sensory score of the UV-sterilized AS was significantly lower than that of the untreated AS, the sensory score was better under the condition of 390 W and 852~1,358 mL/min than under the other conditions examined. ANOVA did not reveal a significant difference in pH, total acidity, sugar content and color characteristic under all conditions tested (p<0.05). Considering the overall attributes of the AS quality, the optimum sterilization condition was determined to be 390 W and 852~1,358 mL/min.

The effects of PEP-1-FK506BP on dry eye disease in a rat model

  • Kim, Dae Won;Lee, Sung Ho;Ku, Sae Kwang;Lee, Ji Eun;Cha, Hyun Ju;Youn, Jong Kyu;Kwon, Hyeok Yil;Park, Jong Hoon;Park, Eun Young;Cho, Sung-Woo;Han, Kyu Hyung;Park, Jinseu;Eum, Won Sik;Choi, Soo Young
    • BMB Reports
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    • v.48 no.3
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    • pp.153-158
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    • 2015
  • As FK506 binding proteins (FK506BPs) are known to play an important role in the regulation of a variety of biological processes related to cell survival, this study was designed to examined the protective effects of FK506 binding protein 12 (FK506BP) on low humidity air flow induced dry eye in a rat model using transduced PEP-1-FK506BP. After the topical application of PEP-1-FK506BP, tear volumes were markedly increased and significant prevention of cornea damage was observed compared with dry eye rats. Further, immunohistochemical analysis demonstrated that PEP-1-FK506BP markedly prevented damage to the cornea, the bulbar conjunctiva, and the palpebral conjunctiva epithelial lining compared with dry eye rats. In addition, caspase-3 and PARP expression levels were found to be decreased. These results demonstrated that topical application of PEP-1-FK506BP significantly ameliorates dry eye injury in an animal model. Thus, we suggest that PEP-1-FK506BP can be developed as a new ophthalmic drop to treat dry eye diseases.