• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.2B
• /
• pp.179-186
• /
• 2006

Effective interception area of street grate inlets was decreased by clogging with trash, debris, and sand. It also decreased the interception capability of grate inlets and increased the inundation area in street. Therefore, it is necessary to analyze the clogging characteristics and interception capability change by clogging for appropriate design and management of grate inlets. Hydraulic experimental apparatus which can be changed the gutter transverse slopes, longitudinal slopes of street and clogging condition of grate inlet ($40{\times}50cm$) was installed for this study. 81 total experiments were conducted with 8 different clogging condition. The interception capacities of grate inlets clogged curb direction are smaller than those of clogged flow direction. As the longitudinal slopes of street increase, the interception capacity of grate inlet decreases due to splash-over phenomena. This is also observed at grate inlets which has no clogging condition. In general, 50% of clogging factor was selected in design of grate inlet in foreign country. The clogging factor for same clogging condition are suggested 0.25~0.65 in domestic urban area.

• Korean Journal of Mineralogy and Petrology
• /
• v.33 no.4
• /
• pp.407-417
• /
• 2020

The capacity of the designated landfill site for asbestos-containing waste is approaching its limit because the amount of asbestos-containing slate is increasing every year. There is a need for a method that can safely and inexpensively treat asbestos-containing slate in large capacity and at the same time recycle it. A cement kiln can be an alternative for heat treatment of asbestos-containing slate. We intend to develop a pilot scale device that can simulate the high temperature environment of a cement kiln using a high temperature plasma reactor in this study. In addition, this reactor can be used to inactivate asbestos in the slate and to synthesize one of the minerals of cement, to confirm the possibility of recycling as a cement raw material. The high-temperature plasma reactor as a pilot scale experimental apparatus was manufactured by downsizing to 1/50 the size of an actual cement kiln. The experimental conditions for the deactivation test of the asbestos-containing slate are the same as the firing time of the cement kiln, increasing the temperature to 200-2,000℃ at 100℃ intervals for 20 minutes. XRD, PLM, and TEM-EDS analyses were used to characterize mineralogical characteristics of the slate before and after treatment. It was confirmed that chrysotile [Mg3Si2O5(OH)4] and calcite (CaCO3) in the slate was transformed into forsterite (Mg2SiO4) and calcium silicate (Ca2SiO4), a cement constituent mineral, at 1,500℃ or higher. Therefore, this study may be suggested the economically and safely inactivating large capacity asbestos-containing slate using a cement kiln and the inactivated slate via heat treatment can be recycled as a cement raw material.

• Culinary science and hospitality research
• /
• v.21 no.1
• /
• pp.1-14
• /
• 2015

Pork belly(PB) and pork shoulder(PS) parts were tested to find out chemical and physical characteristics and sensory evaluation with various cooking methods such as pan heating, boiling, grilling, steaming, charcoal heating, pan heating and double-layer pan filled with phase change material (PCM) cooking. The moisture contents of steamed PB and PS had higher results of 60.2% and 67.2% than other treatments. The highest results of crude fat contents in PB treatments was charcoal roasting as 33.2% (p<0.05) while grilling resulted the highest at 16.0% in the PS (p<0.05). In the crude protein contents, boiling treatment resulted the lowest at 15.4% while steaming was the highest at 18.9% in PB. Also, crude protein content of grilling treatment was 25.2%, a result significantly higher than in other cooking methods in PS. Heating loss, which has a close relationship with water holding capacity, showed the highest result in the charcoal treatment at 40.18% and 39.68% each in the both of PS and PS. In the result of shear force, the lowest result was oven treatment at $2.76kg/cm^2$ in PB (p<0.05) and double-layer pan heating at $3.67kg/cm^2$ in PS (p<0.05). L value in the color test of boiling treatment showed the highest result of 65.16 and 59.72 in the PB and PS respectively (p<0.05), however it scored the lowest of 2.32 in b value in PB (p<0.05). In the 9 point-scale sensory evaluation, grilling treatment showed the highest result of 7.56 in the overall palatability of PB (p<0.05). However, PS in the pan heating which scored 7.22 was the best result while having the lowest score of 5.88 in the boiling treatment (p<0.05).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.6
• /
• pp.2303-2315
• /
• 2013

In general, the waterway was installed for drain water from steep slope and waterway cover was set up to prevent overflow and water separation at berm of waterway. In this study, hydraulic experiment was conducted to analyze the flow characteristics and enact standard design criteria of the waterway. Hydraulic experimental apparatus which can change the slope of waterway and the length of berm were installed to analyze of flow characteristics at the waterway. The slopes of waterway were $40^{\circ}$, $50^{\circ}$, $60^{\circ}$, and $70^{\circ}$ and the range of discharge were 1.0~5.6 ${\ell}/s$. The flow in berm was distinguished two types such as hydraulic jump and splash flow. These kinds of flows depended on the rates of discharge in waterway. When inlet discharge was below 1.1~2.0 ${\ell}/s$, the separation phenomenon of water was generated at upper and lower portion in berm by the splash flow. The scattering range of water particles and length of water separation was measured depending on the slope of waterway. The start point of scattering was about 20 cm(1.3B) from the place connected upper waterway with brem and the length of water separation was till 210 cm(3.5B) from the place connected lower waterway with brem. Therefore, the waterway cover needed to install from starting of berm to 1B and from the lower part of berm to 3.5B.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.4
• /
• pp.324-331
• /
• 2013

All evacuated tube collector is being constantly studied since it can reduce the conductive heat loss in absorber by using vacuum technology and has advantage of heat transport capacity and quick thermal response in comparatively small temperature difference. This study investigated the dynamic thermal performance of the solar collector with the control condition of solar irradiance and fluid temperature by using performance experimental apparatus which is combined with solar collector and refrigerator, examined the thermal characteristics in definite temperature range of fluid in constant temperature tank by simultaneously measuring refrigerating performance. As a result of it, I deducted the related equation of collector efficiency and found that mean collector efficiency has increased through quick heat transfer characteristics according to increase of outdoor temperature and irradiance in case of outlet temperature of constant temperature tank $22^{\circ}C$ when set outlet temperature of solar collector $25^{\circ}C$ with outlet temperature of constant temperature tank $18^{\circ}C$ & $22^{\circ}C$. Also COP of refrigerator was acquired value of 6.2~7.1 at outlet temperature of constant temperature tank $18^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.1
• /
• pp.34-41
• /
• 2006

The objectives of this study were to investigate the affecting factors on streaming current(SC) and to evaluate set point(SP). For the study, a pilot scale apparatus with a capacity of 12 L/min was operated at Guui water intake of Seoul. SC was monitored with varying poly aluminium chlorides(PACs) dose and water quality parameters like conductivity, turbidity, temperature, and pH. The removal efficiencies were evaluated in terms of turbidity and dissolved organic carbon(DOC) with varying coagulation conditions. The effects of affecting factors on SC and SP were also estimated. According to the result observed from the variation of SC with water quality parameters during the experimental period, tendencies of SC and conductivity were very similar, and SC and conductivity had a strong linear relation. At the optimum condition of coagulation, SP decreased as the rainy season changed to the dry season, during the experimental period. Especially, in condition of low turbidity, conductivity had relatively more effect on SC than turbidity. As conductivity increased, SP decreased and coagulant dose per unit increase of SC gradually increased. In view of the results so far obtained, it may be possible to determine the SP range considering the real time variation of water quality, especially conductivity.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.6
• /
• pp.52-59
• /
• 2010

As electric power demand of customers is constantly increasing, more bulk power systems are needed to install in a network. By development of renewable energies and high-efficient facilities and deregulated electricity market, moreover, the amount of distributed resource is considerably increasing in distribution network consequently. Also, distribution network has become more and more complex as mesh network to improve the distribution system reliability and increase the flexibility and agility of network operation. These changes make fault current increase. Therefore, the fault current will exceed a circuit breaker capacity. In order to solve this problem, replacing breaker, changing operation mode of system and rectifying transformer parameters can be taken into account. The SFCL(Superconducting Fault Current Limiter) is one of the most promising power apparatus. This paper proposes a methodology for on optimal location of SFCL. This place is defined as considering the decrement of fault current by component type and the increment of reliability by customer type according to an location of SFCL in a distribution network connected with DG(Distributed Generation). With case studies on method of determining optimal location for SFCL applied to a radial network and a mesh network respectively, we proved that the proposed method is feasible.

• Journal of Korean Society of Water and Wastewater
• /
• v.9 no.3
• /
• pp.116-126
• /
• 1995

The purpose of this study was to investigate the removal of ammonium nitrogen by biological nitrification in raw water containing LAS using BAC. At batch teats, LAS removal by ozone followed the first order reaction, and the rate constants(k) by ozone dose 1, 3mg/min.L were $0.040min^{-1}$, $0.062min^{-1}$ respectively. Therefore, the more ozone was dosed, the higher LAS was removed The reaction between ozone and ammonium nitrogen also followed the first order, and rate constants(k) at pH7,8 and 9 were $8.9{\times}10^{-4}min-1$, $3.8{\times}10^{-3}min^{-1}$, and $2.9{\times}10^{-2}min^{-1}$ respectively at ozone dose of 3mg/min.L . Therefore, ammonium nitrogen was little removed by ozone under neutral pH of 7. The continuous flow apparatus had four sets composed of a ozone contacter and a GAC column. Through continuous filtration test for 50days, the following conclusions were derived; (1) LAS was removed 23%, 30% respectively by ozone dose 1, 3mg/L, and was not detected in all column effluents during the period of experiment. Therefore, it appeared that adsorption capacities of each column still remained. (2) Ammonium nitrogen concentration after ozone contact varied little in raw Water because pH of raw water was from 6 to 7, and was transfered to nitrite and nitrate within GAC columns as the result of staged nitrification. After 30days, nitrite was not detected in all column effluents due to biological equilbrium between nitro semonas and nitrobacter Average removals of ammonium nitrogen in each column after the lapse of 30days were the following; ${\cdot}$ column A (ozone dose 3mg/L, EBCT 9.5min): about 100% ${\cdot}$ column B (ozone dose 1mg/L, EBCT 9.5min): 91% ${\cdot}$ column C (ozone dose 3mg/L, EBCT 14.2min): about 100% ${\cdot}$ column D (ozone dose 0mg/L, EBCT 9.5min): 53% Though column A and C reached nitrification of about 100%, column C (longer EBCT than column A) was more stable than column A. (3) After backwash, nitrification reached steady state within 5 to 8 hours. Therefore, nitrification was not greatly affected by backwash. (4) According to the nitrification capacity in depth of column A, C, where 100% nitrification occured. LAS was removed within 20cm, while ammonium nitrogen required more depth to be removed by nitrification.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.2
• /
• pp.147-160
• /
• 2002

According to the Korean Design Code for port and harbor facilities, bearing capacity of rubble mound under eccentric and inclined load is calculated by the simplified Bishop method, and strength parameters are recommended to be c=0.2kg/$cm^2$ and \phi=35^P\circ}$ fur standard rubble if the compressive strength of parent rock is greater than 300kg/$cm^2$, according to research results by Junichi Mizukami(1991). But this facts have never been verified in Korea because there was no large-scale triaxial test apparatus until 2000 in Korea. For the first time in Korea, the large-scale triaxial test(sample diameter 30cm ; height 60cm) on the rubble originated from porous basalt rock in North-Cheju was accomplished. Then strength parameters for basalt rubble produced in North-Cheju are recommended to be c:0.3kg/$cm^2\; and \phi=36^{\circ}$ if the compressive strength of parent rock is greater than 400kg/$cm^2$. And the shear behavior characteristics of rubble, represented as particle breakage and dilatancy, are investigated.

• Journal of the Korean Electrochemical Society
• /
• v.5 no.3
• /
• pp.125-130
• /
• 2002

An attempt was made for the application of porous reticular metal to a heat dissipation material in semiconductor process. For this aim, the electrodeposition of Fe/Ni alloy on the porous reticular Cu has been performed to minimize the thermal expansion mismatch between Cu skeleton and electronic chip. Preliminary tests for the electrodeposition of Fe/Ni alloy layer were conducted by using standard Hull Cell to examine the effect of current density on the composition of alloy layer. It seemed that mass transfer affected significantly the composition of Fe/Ni layer due to anomalous codeposition in the electrodeposition of Fe/Ni alloy. A paddle type stirring bath, which was employed to control the mass transfer of electrolyte in the work, was found to allow the electrodeposition Fe/Ni with a precise composition. result showed that the thermal expansion of Fe/Ni alloy layer was much lower than that of pure copper. From the tests of heat dissipation by using the apparatus designed in the work the heat dissipation material fabricated in the work showed the excellent heat dissipation capacity, namely, more than two times as compared to that of pure copper plate.