• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.41-47
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• 2017

By using liquid and gaseous nitrogen as simulants, effects of pintle opening distance and simulant supplying condition on spray from pintle injector were investigated qualitatively. The experiment was performed by fixing the liquid supply pressure and varying the opening of the pintle and the supply pressure of gaseous nitrogen. Shadowgraph method with CCD camera was used for image visualization, and the differences of liquid-gas spray were compared by image post processing. In case of liquid nitrogen single injection, as the opening distance was increased, the injection speed was decreased. Therefore, the end of liquid sheet were converged to the center of spray. In the case of liquid nitrogen/Gaseous nitrogen spray, although shadowgraph images look similar to each other, It is shown that it can be analysed by image post processing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.132-140
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• 1998

This study aimed to verify the nutritional and curative effects of protein hydroysate and optimal ratio between protein and protein hydroysate as nitrogen source in rats with cysteamine-induced duodenal ulcer. Duodenal ulcer rat model was established by intraperitoneal injections of cysteamine. Sprague-Dawley, female rats weighing approximately 200g were intrapertionealy injected twice cysteamine(13mg/100g BW) at intervals of 3hours per day. This procedure was repeated 3 times at intervals of 3 days. Animals fed on 10% casein diet for injection periods. After last injection, 5 kinds of kiets (the ratio of casein and casein hydrolysate was 100 : 0(C100), 75 : 25(CH 25), 50 : 50(CH 50), 25 : 75(CH 75), 0 : 100(CH 100)) were given. The rate were sacrificed after feeding diet, 1, 3, 5 days. Ulcer index, hexosamine content of stomach and duodeum, gastric motility, trypsin activity, blood glutathione, plasma total protein, albumin, amino-N, urinalry urea nitrogen, creatinine, hydroxyproline and retention rate of nitrogen were analyzed for nutritional effects of diet treatments. There were no differences among diet groups in the view of the growth and diet treatments. There difference of ulcer curation by diet was appeared after 3 days. The ulcer indexes of C100 and CH 25 of 3, 5 days were significantly higher than those of CH 50, CH 75 and CH 100. This result was the same as hexosamine content of stomach, plasma protein, albumin concentration and nitrogen retention rate. The more casein hydrolysate diet had, the lower trypsin activity was. The more casein gydroysate diet had, the higher excretion of hydroxyproline was. These results show that protein hydrolysate can be applied in diet therapy for the patients with gastronitestinal ulcer. It suggests that it has curative effect of diet when nitogen sources include at least over than 50% of protein hydrolysate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.965-967
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• 2000

An on-line FIA system in place of traditional Conway method was used for quicker and simpler analysis of volatile basic nitrogen of pork. The on-line system was developed by connecting an FIA apparatus with an ammonia electrode as a detector to a personal computer. The data from Conway method and from the on-line FIA system were in good agreement and the correlation coefficient was 0.981. One sample could be analyzed in about 4 min.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.84-93
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• 2004

This study was performed : 1) to find the suitable HRT(hydralic retention time), 2) to evaluate the effects of the ratio of mixing/aeration time and injection time of external carbon source, for the removal of organics, nitrogen and phosphorus in swine wastewater by SBR(sequencing batch reactor process), which is one of the biological treatment process. The result of this study were summarized as follows : (1) As the ratio of mixing/aeration time was higher, $NH_4{^+}-N$ removal efficiency was increased and it was increased with increasing injection time of external carbon source because nitrification was affected by denitrification microbes propagation when injection time of external carbon soruce was shorted. T-N removal efficiency was increased with increasing the ratio of mixing/aeration time and injection time of external carbon source. (2) The T-P removal efficiency showed a great difference in each operating condition, and it was increased with increasing the ratio of mixing/aeration time increased and when the injection time of external carbon source was shorted because denitrification was done with effect by denitrification microbes propagation. (3) The highest removal efficiency of organic and nitrogen were obtained by the operating condition of Run 4-1(the ratio of mixing/aeration time : 16.5/5.5, injection time of external carbon source : 15hours) and T-P were obtained by the operation condition of Run 4-2(the ratio of mixing/aeration time : 16.5/5.5, injection time of external carbon source : 3hours), and efficiency(effluent concentration)of $BOD_5$, $COD_{Mn}$, $COD_{Cr}$, T-N and T-P in the treated water was 96.1%, 87.7%, 90.6%, 86.6% and 84.5%, respectively.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.437-446
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• 2004

To develop sewage treatment apparatus by natural purification method, the sewage treatment plant that consisted of aerobic and anaerobic plot was constructed. And then, the effects of treatment conditions on the removal of pollutants in the relation to sewage loading, sewage injection method and season according to the pebble kind. Removal rate of BOD and COD according to the sewage loading in effluent were over 95 and 77%, respectively. Removal rate of nitrogen in treated water by aerobic plot and effluent using sand were about 22~40 and 49~75%, respectively. Those of effluent using sand 75%+ oyster shell 25% and sand 50%+ oyster shell 50% as filter media in comparison with using sand were about 7~25 and 16~23%, respectively. Removal rate of phosphorus in treated water by aerobic plot and effluent using sand as filter media were about 30~36 and 52~56%, respectively. Those of effluent using sand 75%+ oyster shell 25% and sand 50%+ oyster shell 50% in comparison with using sand as filter media were about 11~40 and 12~45%, respectively. Removal efficiency of BOD and COD according to the intermittent injection method of sewage were slightly decreased, but those of nitrogen and phosphorus were little varied in comparison with continuous injection method. Removal efficiency of BOD and COD in winter in comparison with the others were little varied, but those of nitrogen and phosphorus slightly decreased.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.911-917
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• 2015

The objective of this work focuses on the analysis of injection rate and macroscopic spray behavior characteristics with injection pressures as well as combustion and exhaust emission characteristics with injection timing and injection pressure by using a common rail single-cylinder diesel engine. The injection rate was measured by applying the Bosch method, and macroscopic spray behavior characteristics were analyzed with a constant-volume vessel and a high-speed camera. In addition, combustion and emission characteristics were analyzed in a common-rail single-cylinder diesel engine with precise control of fuel injection timing and pressure. For injection pressures of 30MPa and 50MPa, the injection rate was higher at 50 MPa, and the spray development (penetration) was also higher in the same elapsed time. The peak in-cylinder pressure and rate of heat release showed a tendency to decline as injection timing was delayed, and the peak in-cylinder pressure and rate of heat release were slightly higher for higher injection pressures. Higher injection pressures also reduced the mean effective pressure, while the indicated mean effective pressure and torque increased as injection timing was delayed to TDC. Nitrogen oxides had a peak level at injection timings of $BTDC20^{\circ}$(30MPa) and $BTDC15^{\circ}$(50MPa); carbon monoxide emissions were reduced by delaying injection timing from $BTDC30^{\circ}$.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.141-147
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• 2012

A direct injection diesel engine with large amount of exhaust gas recirculation was used to investigate low temperature diesel combustion. Pilot injection strategy was adopted in low temperature diesel combustion to reduce high carbon monoxide and hydrocarbon emissions. Combustion characteristics and exhaust emissions of low temperature diesel combustion under different pilot injection timings, pilot injection quantities and injection pressures were analyzed. Retarding pilot injection timing, increasing pilot injection quantity and higher injection pressure advanced main combustion timing and increased peak heat release rate of main combustion. As a result of these strategies, carbon monoxide and hydrocarbon emissions were reduced. Soot emission was slightly increased with retarded pilot injection timing while the effect of pilot injection on nitrogen oxides emission was negligible under low combustion temperature condition. Spatial distribution of fuel from the spray targeting visualization was also investigated to provide more insight into the reason for the reduction in carbon monoxide and hydrocarbon emissions.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.142-148
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• 2018

To improve the performance of a launch vehicle, kerosene, a launch vehicle fuel, undergoes a densification process. Liquid nitrogen injection cooling is an effective densification method which has a simple system and is inexpensive. During the cooling process, however, nitrogen may dissolve in the kerosene, possibly resulting in changes to fuel properties. Therefore, it is essential to measure and eliminate the amount of dissolved nitrogen in the kerosene. In this study, the vacuum extraction principle is introduced to measure the content of dissolved nitrogen in the kerosene. In addition, the experimental results, which used a designed/manufactured nitrogen sampling device, are described. From the results, the validity of the nitrogen sampling device and the dissolved nitrogen measurement/elimination methods was demonstrated.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.330-336
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• 2005

The ozone injection method was proposed to improve the catalytic process for the removal of nitrogen oxides ($NO_x$). Nitric oxide (NO) in the exhaust gas was first oxidized to nitrogen dioxide ($NO_2$) by ozone produced by dielectric barrier discharge, and then the exhaust gas containing the mixture of NO and $NO_2$ was directed to the catalytic reactor where both NO and $NO_2$ were reduced to $N_2$ in the presence of ammonia as the reducing agent. A commercially available $V_2O_5-WO_3/TiO_2$ catalyst was used as the catalytic reactor. The $NO_2$ content in the mixture of NO and $NO_2$ was changed by the amount of ozone added the exhaust gas. The effect of reaction temperature, initial $NO_x$ concentration, feed gas flow rate, and ammonia concentration on the removal of $NO_x$ at various $NO_2$ contents was examined and discussed. The increase in the content of $NO_2$ by the ozone injection remarkably improved the performance of the catalytic reactor, especially at low temperatures. The present ozone injection method appears to be promising for the improvement of the catalytic reduction of $NO_x$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.262-269
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• 2016

This study examined the influent of a sulfur denitrification reactor using nitrified effluent from a batch type reactor. The denitrification efficiency was compared according to the injection type. The nitrogen removal effects were compared with the changes in the EBCT and nitrogen concentration of the influent to determine the optimal operation conditions with the selected injection type. A denitrification efficiency evaluation of a reactor according to the change in injection type and up-flow was performed using a lower organic concentration of the effluent than the down-flow because of the re-precipitation of desorbed microbes and spilled solids. In the up-flow type, organics were controlled by the low concentration than the down-flow type because of solid re-precipitation. The T-N removal efficiency of the up-flow type was 73.3~90.2%, which was more that 10% higher that down-flow type. This means that the up-flow type has a great advantage in removing T-N and organics. The T-N removal efficiency by EBCT at 1hr was 47.3%, and was 88.1% and 90.5% by EBCT 3hr and 5hr, respectively. Therefore, the optimal operation conditions to remove nitrogen was considered to be EBCT for 3hr. After careful consideration of rule of law and T-N removal effects, the T-N load factor in the reactor should remain below $0.443kgT-N/m^3{\cdot}day$ to maintain the legal total nitrogen concentration for discharge, which is 20mg/L.