• Proceedings of the KSR Conference
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• 2007.11a
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• pp.658-670
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• 2007

Most railroad accidents are due to human errors. In particular, most of the causes of these accidents are faults of an engine driver, such as lack of signal confirmation, insecure braking, driving by guess or force of habit. This paper identifies a problem(s) by analyzing accidents for the past 10 years and also seeks a solution to train good engine drivers in order to prevent railroad accidents. In summary, what is needed are: 1) proper placement of various manpower, 2) proper training of engine drivers, 3) proper legislation for a 2-man on board system, and 4) proper reformation of personnel management.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.126-134
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• 2006

This paper describes the development of an embedded wireless LAN controller which can be in parallel operated with an existing utility controller. The embedded controller mainly consists of Prism(R) 2.5 chip set and Atmega 128 microcontroller. In order to communicate over the network, the controller including TCP/IP stack (IP, TCP, UDP, and ICMP), telnet, and X/Z modem has been developed. For a specific application, we have proposed an special method to convert data structure between TCP/IP and X/Z modem and a data buffer algorithm to minimize the RAM memory usage. Finally, the correctness and performance of the protocols are tested and verified using $CommView^{(R)}\;and\;DU^{(R)}$. The development is satisfactorily operated only for 3,381 bytes of RAM usage without sacrificing interoperability between hosts.

• Nuclear Engineering and Technology
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• v.23 no.4
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• pp.420-425
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• 1991

The Rb charge exchange cell is constructed as the He- ion source of the SNU 1.5- MV Tandem Van do Graaff accelerator. The characteristic experiment is carried out in order to determine the optimum operational conditions of the cell. The $He^{+}$ ion beam with the energy of 1~10 keV, extracted from the duoplasmatron ion source, is passed through the Rb vapor to become He- ions by the two step charge exchange reaction, i.e., $He^{+}\;+\;Rb\;{\rightarrow}\;He^{\circ\ast}\;+\;Rb^{+}\;and\;He^{\circ\ast}\;+\;Rb\;{\rightarrow}\;He^{-}\;+\;Rb^{+}$. From the experimental results, it is found that the maximum fractional yield of $He^{-}$ ions is produced at He+ ion energy of 7 keV. The optimum temperatures of the oven and the canal are determined to be $370\;^{\circ}C{\;}and{\;}95^{\circ}C$ respectively. Under the optimum operational condition the maximum fractional yield of $He^{-}$ ions is $2.42\pm0.02%$ This charge exchange cell is proved to be an effective system for the production of He- ions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.38-45
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• 2006

The superconducting fault current limiters(SFCLs) provide the effect such as enhancement in power system reliability due to limiting the fault current within a few miliseconds. Among various SFCLs we have developed a flux-lock type SFCL and exploited a special design to effectively reduce the fault current according to properly adjustable magnetic field after the short-circuit test. This SFCL consists of two copper coils wound in parallel on the same iron core and a component using the YBCO thin film connected in series to the secondary copper coil. Meanwhile, operating characteristics can be controlled by adjusting the inductances and the winding directions of the coils. To analyze the operational characteristics, we compared closed-loop with open-loop iron core. When the applied voltage was 200[Vrms] in the additive polarity winding, the peak values of the line current the increased up to 30.71[A] in the closed-loop and 32.01[A] in the open-loop iron core, respectively. On the other hand, in the voltages generated at current limiting elements were 220.14[V] in the closed-loop and 142.73[V] in the opal-loop iron core during first-half cycle after fault instant under the same conditions. We confirmed that the open-loop iron core had lower power burden than in the closed-loop iron core. Consequently, we found that the structure of iron core enabled the flux-lock type SFCL at power system to have the flexibility.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.562-566
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• 2012

A novel design of tubular segmented-in-series(SIS) solid oxide fuel cell (SOFC) sub module was presented in this paper. The tubular ceramic support was fabricated by the extrusion technique. The NiO-YSZ anode and the yttria-stabilized zirconia (YSZ) electrolyte were deposited onto the ceramic support by dip coating method. After sintering at $1350^{\circ}C$ for 5 h, a dense and crack-free YSZ film was successfully fabricated. Also, the multi-layered cathode composed of LSM-YSZ composite, LSM and LSCF were coated onto the sintered ceramic support by dip coating method and sintered at $1150^{\circ}C$. The performance of the tubular SIS SOFC cell and sub module electrically connected by the Ag-glass interconnect was measured and analysed with different fuel flow and operating temperature.

• Membrane Journal
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• v.8 no.2
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• pp.77-85
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• 1998

To treat effectively EDIR (electrodeposition ion removal) wastewater in terms of CO$_{Mn}$ 1,500~2,000 ppm generated from aluminum painting process, a RO (reverse osmosis) process was designed and installed to recover and reuse the concentrated solvent sent back to the electrocodeposition tank while the permeate reused as rinse water. A RO system in which three polyamide-spiral wound modules ($102\Phi \times 1,016L$ mm) connnected in series had been running to treat 20 m$^3$ in waste volume in 3 days batch operation at the condition of system recovery of 30 %, applied pressure 11.5 $kg_f/cm^2$ and room temperature. During 42 hours continuous operation leading to 5-fold decrease in waste volume, nearly constant permeation flux of 390 l/m$^2$-hr was maintained and the permeate with average CO$_{Mn}$, 300 ppm was obtained which could be used for washing the remaining paint solution in ion-exchange tower instead of demineralized water. Also COD$_{Mn}$ rejection as a function of running time was observed to be in the range of 78~87 % and the observed solvent rejections for ethyl cellusolve, buthyl cellusolve and n-butanol were 79 %, 87 % and 70 %, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.295-302
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• 2014

This study demonstrates a double-path CDI as an alternative of advanced wastewater treatment process. While the CDI typically consists of many pairs of electrodes connected in parallel, the new double-path CDI is designed to have series flow path by dividing the module into two stages. The CFD model showed that the double-path had uniform flow distribution with higher velocity and less dead zone compared with the single-path. However, the double-path was predicted to have higher pressure drop(0.7 bar) compared the single-path (0.4 bar). From the unit cell test, the highest TDS removal efficiencies of single- and double-path were up to 88% and 91%, respectively. The rate of increase in pressure drop with an increase of flow rate was higher in double-path than single-path. At 70 mL/min of flow rate, the pressure drop of double-path was 1.67 bar, which was two times higher than single-path. When the electrode spacing was increased from 100 to $200{\mu}m$, the pressure drop of double-path decreased from 1.67 to 0.87 bar, while there was little difference in TDS removal. When proto type double-path CDI was operated using sewage water, TDS, $NH_4{^+}$-N, $NO_3{^-}$-N and $PO_4{^{3-}}$-P removal efficiencies were up to 78%, 50%, 93% and 50%, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.113-120
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• 2006

Wastewater generated through the food waste recycling process have known high concentration, BOD 20,000~150,000 mg/L, which has to treat to the proper level because of a ban on reclamation. But it is impossible to treat less than 10 days by existing water treatment plant. Ecodays Ltd. is to treat this wastewater during 2~4 days by ER-1, which can simultaneously induce the modified PFR(Plug Flow Reactor) of the oxygen transfer rate, MLVSS concentration, and influent concentration to top from bottom of reactor. We tested the pilot test about low concentration food wastewater(BOD 16,500 mg/L) and high concentration food wastewater(64,431 mg/L) at the food waste recycling plant of H-Gun(20t/d). Hydraulic retention time(HRT) of ER-1 for low concentration food wastewater is 2.5day. In low concentration conditions, ER-1 treatment efficiency is to appear BOD 99%, COD 98%, TN 97%, and TP 96%. While ER-1 process for high concentration food wastewater treatment is composed 2 stages, which are to be HRT 2.5day for law wastewater and HRT 1.5 day for secondary treatment. In high concentration conditions, ER-1 treatment efficiency is to appear BOD 97%, COD 84%, TN 66%, and TP 95%. It is treated without temperature control about high temperature($50^{\circ}C$) to appear low treatment efficiency in high concentration conditions.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.283-287
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• 2007

KIER has been developing the anode-supported flat tubular solid oxide fuel cell unit bundle for the intermediate temperature($700{\sim}800^{\circ}C$) operation. Anode-supported flat tubular cells have Ni/YSZ cermet anode support, 8 moi.% $Y_2O_3$ stabilized $ZrO_2(YSZ)$ thin electrolyte, and cathode multi-layer composed of Sr-doped $LaSrMnO_3(LSM)$, LSM-YSZ composite, and $LaSrCoFeO_3(LSCF)$. The prepared anode-supported flat tubular cell was joined with ferritic stainless steel cap by induction brazing process. Current collection for the cathode was achieved by winding Ag wire and $La_{0.6}Sr_{0.4}CoO_3(LSCo)$ paste, while current collection for the anode was achieved by using Ni wire and felt. For making stack, the prepared anode-supported flat tubular cells with effective electrode area of $90\;cm^2$ connected in series with 12 unit bundles, in which unit bundle consists of two cells connected in parallel. The performance of unit bundle in 3% humidified $H_2$ and air at $800^{\circ}C$ shows maximum power density of $0.39\;W/cm^2$ (@ 0.7V). Through these experiments, we obtained basic technology of the anode-supported flat tubular cell and established the proprietary concept of the anode-supported flat tubular cell unit bundle.