• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.808-812
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• 2013

A new type of microbial fuel cell (MFC) with anaerobic membrane filter was designed to produce bioelectricity and to treat domestic sewage at relatively high organic loading rate (OLR) of $6.25kgCOD/m^3/day$ and short hydraulic retention time (HRT) of 1.9 h. A following aeration system was applied to ensure effluent water quality in continuous operation. Glucose was supplemented to increase the influent concentration of domestic sewage. Influent substrate of 95% was removed via the MFC and following aeration system and the corresponding maximum power density was $25.6mW/m^3$. External resistor of $200{\Omega}$ and air-cathode system contributed better MFC performance comparing to $2000{\Omega}$ and dissolved oxygen as a catholyte.

• Tunnel and Underground Space
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• v.33 no.2
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• pp.83-94
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• 2023

Unlike the conventional triaxial test cells for cylindrical specimens, which impose uniform lateral confining pressures, the GREAT (Geo-Reservoir Experimental Analogue Technology) cell can exert differential radial stresses using eight independently-controlled pairs of lateral loading elements and thereby generate horizontal stress fields with various magnitudes and orientations. In the preceding companion paper, GREAT cell tests were numerically simulated under different mechanical loading conditions and the validity of the numerical model was investigated by comparing experimental and numerical results for circumferential strain. In the present study, we simulated GREAT cell tests for an artificial sample containing a fracture under both mechanical loading and fluid flow conditions. The numerical simulation was carried out by varying the mechanical properties of the fracture surface, which were unknown. The numerical responses (circumferential strains) of the sample were compared with experimental data and a good match was found between the numerical and experimental results under certain mechanical conditions of the fracture surface. Additionally, the effect of fluid flow conditions on the mechanical behavior of the sample was investigated and discussed.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.378-381
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• 2003

The characteristics of bio-beads made of various supports, in which denitrifying bacteria were entrapped after those cells were isolated from sludge in wastewater treatment plants, were studied in order to develop a novel BNR system. Four species were isolated, and the bead made of 12% PVA showed the highest denitrification rate. The best concentration of cell loading was 200 mg/ml, and there was no significant difference in performance by bead sizes. The bead reached the maximum denitrification rate after 4 batch experiments, and with cell leaking of $10^3$ CFU/ml its capacity retained until 25 batches.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.113-130
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• 2002

In this paper, we developed DNL(Dynamic Network Loading) model based on Moving cell theory to analyze the dynamic characteristics of traffic flow in congested network. In this paper vehicles entered into link at same interval would construct one cell, and the cells moved according to Cell following rule. In the past researches relating to DNL model a continuous single link is separated into two sections such as running section and queuing section to describe physical queue so that various dynamic states generated in real link are only simplified by running and queuing state. However, the approach has some difficulties in simulating various dynamic flow characteristics. To overcome these problems, we present Moving cell theory which is developed by combining Car following theory and Lagrangian method mainly using for the analysis of air pollutants dispersion. In Moving cell theory platoons are represented by cells and each cell is processed by Cell following theory. This type of simulation model is firstly presented by Cremer et al(1999). However they did not develop merging and diverging model because their model was applied to basic freeway section. Moreover they set the number of vehicles which can be included in one cell in one interval so this formulation cant apply to signalized intersection in urban network. To solve these difficulties we develop new approach using Moving cell theory and simulate traffic flow dynamics continuously by movement and state transition of the cells. The developed model are played on simple network including merging and diverging section and it shows improved abilities to describe flow dynamics comparing past DNL models.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.556-562
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• 2015

In order to remove the organic substances and the nitrate-nitrogen contained in wastewater, some researchers have studied the simultaneous removal of organics and nitrogen by using different biocathode microbial fuel cells (MFCs). The operating conditions for removing the contaminants in the MFCs are the external resistances, HRTs, the concentration of the influent wastewater, and other factors. This study aimed to determine the effect of the external resistors and organic loading rates, from the changing HRT, on the removal of the organics and nitrogen and on the production of electric power using the Denitrification Biocathode - Microbial Fuel Cell (DNB-MFC). As regards the results of the study, the removal efficiencies of $SCOD_{Cr}$ did not show any difference, but the nitrate-nitrogen removal efficiencies were increased by decreasing the external resistance. The maximum denitrification rate achieved was $129.2{\pm}13.54g\;NO_3{^-}-N/m^3/d$ in the external resistance $1{\Omega}$, and the maximum power density was $3,279mW/m^3$ in $10{\Omega}$. When the DNB-MFC was operated with increasing influent organic and nitrate loading by reducing the HRTs, the $NO_3{^-}-N$ removal efficiencies were increased linearly, and the maximum nitrate removal rate was $1,586g\;NO^3{^-}-N/m^3/d$ at HRT 0.6 h.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.85-88
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• 2002

Maintaining a proper level of cell lead, system throughput can be maximized by a transmission rate control over the uplink in DS/CDMA cellular system to support integrated services of real-time and delay-tolerant traffic. We find that the cell load-based rate control scheme can be further enhanced by taking the varying channel condition into account In conjunction with some fair scheduling algorithm. Our simulation results show that the proposed scheme outperforms the original cell load-based rate control with the round-robin sharing scheduling scheme.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.122-125
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• 2002

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.337-344
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• 2004

Most of the virtual space constructed sufficiently realistic need a lot of memory space to navigate smoothly. And this kind of virtual space also requires real-time responsibility for the navigation as well as realism. In the off-line virtual system, real-time responsibility can be resolved by using large scale if secondary memory. In the web-based online virtual system, on the other hand, real-time responsibility is highly related to the latency time of network data communication. This induces the necessity of the algorithm for fast data loading. In this paper, we propose and verify the validity of the two methodology for cell leading algorithm. According to the results of computer simulation, the algorithm using hexagonal type cell promotes the real-time responsibility over 30％ than that of the rectangular type.

• Steel and Composite Structures
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• v.51 no.1
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• pp.53-61
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• 2024

Aluminum foams sandwich panel (AFSP) has been used in engineering field, where cyclic loading is used in most of the applications. In this paper, the fatigue life of AFSP prepared by the bonding method was investigated through a three-point bending test. The mathematical statistics method was used to analyze the influence of different plate thicknesses and core densities on the bending fatigue life. The macroscopic fatigue failure modes and damage mechanisms were observed by scanning electron microscopy (SEM). The results indicate that panel thickness and core layer density have a significant influence on the bending fatigue life of AFSP and their dispersion. The damage mechanism of fatigue failure to cells in aluminum foam is that the initial fatigue crack begins the cell wall, the thinnest position of the cell wall or the intersection of the cell wall and the cell ridge, where stress concentrations are more likely to occur. The fatigue failure of aluminum foam core usually starts from the semi-closed unit of the lower layer, and the fatigue crack propagates layer by layer along the direction of the maximum shear stress. The results can provide a reference for the practical engineering design and application of AFSP.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.386-392
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• 2020

In this study, the drift current characteristics of charged particles are analyzed for panels fabricated by varying the waveform biasing of the active particle loading method (APLM), which is a method driven by the electrophoretic principle of loading charged particles into a cell of a barrier rib-type electronic paper. We prepare 3 panels using APLM and 1 panel without APLM. The waveform of APLM uses square wave and ramp wave, and the step voltage wave is applied to the driving voltage. The drift currents measured from the square wave and ramp wave with the same period applied by APLM are 4.872 µC and 5.464 µC, respectively, and the ramp wave is shown to be relatively advantageous for loading charged particles that have a large q/m. The time-current curve results confirm that the abrupt movement of charged particles is occurring. When the step form wave signal with a short time of 1s is first applied, initial large movement of the charged particles is confirmed to occur in all samples, which is understood as the effect of applying the voltage necessary to remove the imaging force. The results of this study are expected to improve the loading of charged particles into the electronic paper cell, driven by the electrophoretic principle and optimization of the driving conditions.