• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.655-676
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• 2009

The first-ever integral effect test for simulating a guillotine break of a DVI (Direct Vessel Injection) line of the APR1400 was carried out with the ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation) from the same prototypic pressure and temperature conditions as those of the APR1400. The major thermal hydraulic behaviors during a DVI line break accident were identified and investigated experimentally. A method for estimating the break flow based on a balance between the change in RCS inventory and the injection flow is proposed to overcome a direct break low measurement deficiency. A post-test calculation was performed with a best-estimate safety analysis code MARS 3.1 to examine its prediction capability and to identify any code deficiencies for the thermal hydraulic phenomena occurring during the DVI line break accidents. On the whole, the prediction of the MARS code shows a good agreement with the measured data. However, the code predicted a higher core level than did the data just before a loop seal clearing occurs, leading to no increase in the peak cladding temperature. The code also produced a more rapid decrease in the downcomer water level than was predicted by the data. These observable disagreements are thought to be caused by uncertainties in predicting countercurrent flow or condensation phenomena in a downcomer region. The present integral effect test data will be used to support the present conservative safety analysis methodology and to develop a new best-estimate safety analysis methodology for DVI line break accidents of the APR1400.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.415-420
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• 2013

This study was performed to examine the anesthetic and cardiopulmonary effects of medetomidine, midazolam and ketamine (MMK) combination in ten beagle dogs. Dogs were randomly allocated to two groups. Treatment group MMK-L received 0.015 mg/kg medetomidine followed by 0.3 mg/kg midazolam and 5 mg/kg ketamine by intramuscular injection. Treatment group MMK-H received 0.02 mg/kg medetomidine followed by 0.3 mg/kg midazolam and 5 mg/kg ketamine by intramuscular injection. Induction, anesthesia, sternal recumbency, standing, walking time, heart rate, arterial blood pressure, rectal temperature, respiratory rate and arterial blood gases were measured. Mean anesthesia time was significantly different between MMK-L group ($52.4{\pm}11.08$ minutes) and MMK-H group ($78.2{\pm}20.72$ minutes). Sedative scores and noxious stimuli were raised to the maximum value at 5 minutes after administration of the test dose and maintained until 40 minutes in both groups. In both groups, the heart rate significantly decreased after MMK administration. The blood pressures (MAP, SAP and DAP) increased after MMK administration but there were no significant differences in blood pressures between two groups. In conclusion, intramuscular administration of medetomidine followed by intramuscular injection of midazolam and ketamine in beagle dogs, leads immediate and sufficient anesthesia and proper doses of medetomidine for minimal adverse effects in intramuscular MMK combination will be 0.015 mg/kg in dogs.

• Journal of Advanced Marine Engineering and Technology
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• v.8 no.1
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• pp.17-36
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• 1984

Since 1973, the competition on the development of fuel saving type internal combustion engines has become severe by the two times oil shock, and new type engines are reported every several months. Whenever these new type engines are developed, new designs are required and they will be offered in the market after performing the endurance test for a long time. But the engine market is faced with a heavy burden of finance, as the developing of a new engine requires tremendous expenses. For this reason, the computer simulation method has been lately developed to cope with it. The computer simulation method can be available to perform the reasonable research works by the theoretical analysis before carrying out practical experiments. With these processes, the developing expenses are cut down and the period of development is curtailed. The object of this study is the development of simulation computer program for the small naturally aspirated four-stroke diesel engine which is intended to product by the original design of our country. The process of simulation is firstly investigated for the ideal engine cycle, and secondly for the real engine cycle. In the ideal engine cycle, each step of the cycle is simulated by the energy balance according to the first law of thermodynamics, and then the engine performance is calculated. In the real cycle imulation program, the injection rate, the preparation rate and the combustion rate of fuel and the heat transfer through the wall of combustion chamber are considered. In this case, the injection rate is supposed as constant through the crank angle interval of injection and the combustion rate is calculated by the Whitehouse-Way equation and the heat transfer is calculated by the Annand's equation. The simulated values are compared with measured values of the YANMAR NS90(C) engine and Mitsubishi 4D30 engine, and the following conclusions are drawn. 1. The heat loss by the exhaust gas is well agree with each other in the lower load, but the measured value is greater than the calculated value in the higher load. The maximum error rate is about 15% in the full load. 2. The calculated quantity of heat transfer to the cooling water is greater than the measured value. The maximum error rate is about 11.8%. 3. The mean effective pressure, the fuel consumption, the power and the torque are well agree with each other. The maximum error is occurred in the fuel consumption, and its error rate is about 7%. From the above remarks, it may be concluded that the prediction of the engine performance is possibly by using the developed program, although the program needs to reform by adding the simulation of intake and exhaust process and assumping more reliable mechanical efficiency, volumetric efficiency, preparation rate and combustion rate.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.611-616
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• 2013

Many researches have been carried out consistently for the green ship owing to its economic increasement, efficiency and convenience. One of them is an electronic controlled marine diesel engine. However, we are suffered from dissemination of above engine, due to its anxiety about safety and reliability. In order to solve these problems in this study, emission characteristics test of main propulsive two-stroke diesel engine, equipped both electronic control and cam drive fuel injection systems, has been performed and evaluated under the various load conditions. From the test results, we have confirmed that exhaust gas emission characteristics of the electronic control system is similar to the cam drive system in eco-mode operation, but NOx in emission mode has been decreased 100ppm or more in full load condition. HC emission from the electronic control system is decreased 10~20ppm at 50% load, and 35~40ppm at 25% load in comparison to cam drive system. In fuel consumption, it is considered that 7g/kWh is decreased than the value of cam drive system at 700bar of injection pressure, which is 200bar higher than cam drive system.

• International Journal of Automotive Technology
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• v.5 no.4
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• pp.221-238
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• 2004

Wall interactions of direct injection spray were investigated using laser-sheet imaging, shadowgraphy, wetted footprint and phase Doppler interferometry techniques. A narrow-cone high-pressure swirl injector is used to inject iso-octane fuel onto a plate, which has three different impact angles inside a pressurized chamber. Heated air and plate conditions were compared with unheated cases. Injection interval was also varied in the heated case to compare dry- and wet- wall impingement behaviors. High-speed macroscopic Mie-scattering images showed that presence of wall and air temperature has only minor effect on the bulk spray structure and penetration speed for the narrow-cone injector tested. The overall bulk motions of the spray plume and its spatial position at a given time are basically unaffected until a few millimeters before impacting the wall. The surface properties of the impact surface, such as the temperature, the presence of a preexisting liquid film also have a small effect on the amount of wetting or the wetted footprint; however, they have strong influence on what occurs just after impact or after a film is formed. The shadowgraph in particular shows that the plate temperature has a significant effect on vapor phase propagation. Generally, 10-20% faster horizontal vapor phase propagation is observed along the wall at elevated temperature condition. For impingement onto a preexisting film, more splash and evaporation were also observed. Contrary to some preconceptions, there is no significant splashing and droplet rebounding from surfaces that are interposed in the path of the DI gasoline spray, especially for the oblique impact angle cases. There also appears to be a dense spray front consists of large sac spray droplets in the oblique impact angle cases. The bulk of the spray is not impacted on the surface, but rather is deflected by it The microscopic details as depicted by phase Doppler measurements show that the outcome of the droplet impaction events can be significantly influenced. Only droplets at the spray front have high enough Weber numbers for wall impact to wet, splash or rebound. Using the sign of vertical velocity, the time-resolved downward droplets and upward droplets are compared. The Weber number of upward moving droplets, which seldom exceeds unity, also decreases as the impact angle decreases, as the droplets tend to impact less and move along the wall in the deflected spray plume.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.6-12
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• 2005

Contamination of soils and groundwater by leakage of petroleum compounds from underground storage tanks (USTs) has become great environmental issues. Conventional methods such as soil vapor extraction (SVE) used for the remediation of unsaturated soils contaminated with volatile organic compounds might not be applied for the removal of semi-volatile organic compounds such as diesel fuels and PCBs, which have low volatility and high hydrophobicity. The objective of this study is to develop a hot air injection method to remove semi-volatile compounds. Additionally, operation parameters such as temperature, air flow rate, and water content are evaluated. Experimental results show that diesel ranged organics (DROs) are removed in the order of volatility of organic compounds. As expected, removal efficiency of organics is highly dependent on the temperature. It is considered that more than $90\%$ of organic contaminants whose carbon numbers range between 17 and 22 can be removed efficiently by the hot air injection-extraction method (modified SVE) over the $100^{\circ}C$. It is also found that increased air flow rate resulted in high removal rate of contaminants. However, air flow rate over 40 cc/min is not effective for the operation aspects, due to mass transfer limitation on the volatilization rate of the contaminants. The effect of the water content on the decane removal is minimal, but some components show large dependence on the removal efficiency with increasing water content.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.2
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• pp.365-371
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• 2006

Bee Venom aqua-acupuncture (BVA) simultaneously exerts pharmacological effects of biologically active compounds, existed in the whole bee venom, and medicinal effect of the stimulation of acupuncture points. BVA has been considered as a promising therapeutic method for treating various chronic diseases, mainly accompanying severe pain and inflammation. As a painless injection device, jet injectors have been commercially marketed for various clinical applications including insulin injection and vaccination. Among them, a pressure-driven jet injector system could be used for intradermal delivery of a variety of drugs. The aim of this study was to investigate the analgesic effects of the BVA using a needle-free injector (Biojector $2000^{\circledR}$, Bioject Inc., OR, USA), compared to the conventional BV aqua-acupuncture using a typical syringe. Adult Sprague-Dawley rats were injected with bee venom $(0.08mg/kg,\;50{\mu}l)$ using Biojector $2000^{\circledR}$ (BVA-B) or a syringe (BVA-5) into the Zusanli (ST36) acupoint, 30 minutes before plantar injection of 2% formalin. It was found that BVA-B-, or BVA-5-treated rats, compared to controls, exhibited significantly less licking behavior during the late phase in the rat formalin test, when compared to controls. During early phase, however, those effects were not significant but substantial. The analgesic effect of BVA-B was also compatible with that of the conventional BVA-5. In the immunohistochemical studies, BVA-B significantly suppressed the expression of formalin-evoked c-fos, a biomarker of neuronal activity, in the lumbar dorsal horn of the spinal cord. These results indicated that BVA-B waseffective in the modulation of pain in the rat formalin test, compared to BVA-5. Taken together, the needle-free jet injector system could be substituted for the conventional aqua- acupuncture with the advantage of little pain.

• Journal of Veterinary Clinics
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• v.29 no.3
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• pp.226-232
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• 2012

This study was performed to evaluate the sedative and analgesic effects of intravenous (IV) administration of detomidine (D) and tramadol (T) to horses. Six warmblood horses each received D (10 ${\mu}g/kg$), T (2 mg/kg), and a combination of DT (10 ${\mu}g/kg$ and 2 mg/kg). No significant differences in the heart rate, respiratory rate, rectal temperature, indirect arterial pressure, and gastrointestinal motility between D and DT were observed. The sedative effect was evident within 5 min after D and DT administration, but no significant difference between D and DT was observed. D and DT induced a similar analgesic effect up to 50 min after injection and DT maintained a longer analgesic effect than D. A significant increase in blood glucose was shown for D after the injection, but not for DT. A horse with T and DT showed an excited behavior within 5 min of the injection. This study suggests that the DT combination could be used for diagnostic procedures and simple surgeries in standing horses, with caution for excitement in the early phase after the administration.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.681-687
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• 2014

The objective of this work presented here was focused on analysis of in-cylinder combustion characteristic, engine performance, and nitrogen oxides emission characteristic from marine gas oil for propulsion diesel engine of naval vessels and biodiesel with fuel injection timing in a single cylinder diesel engine. In addition, combustion process was analyzed with a high speed camera of marine gas oil and biodiesel fuel. Retarding the fuel injection timing from $BTDC25^{\circ}CA$ to $BTDC5^{\circ}CA$, in cylinder peak combustion pressure was gradually decreased, however, engine torque showed a tendency to increase. The highest nitrogen oxides level was measured at $BTDC15^{\circ}CA$, they were reduced at retarded and advanced condition on the basis of $BTDC15^{\circ}CA$. Comparing with combustion process of marine gas oil and biodiesel fuel at $BTDC5^{\circ}CA$, self-ignition timing of biodiesel fuel included oxygen content was faster than marine gas oil, however, a cautious observation indicates a slightly higher flame intensity for marin gas oil than biodiesel as a diffusion flame is developing.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.337-343
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• 2009

To apply to novel two-interconnected fluidized beds system for selective solid circulation, a solid separator and a solid circulation system were developed. The solid separation rate increased as the gas velocity through the solid injection nozzle, solid height, and diameter of solid injection nozzle increased. However, the effect of the fluidization velocity was negligible. Coarse($212{\sim}300{\mu}m$) and fine($63{\sim}106{\mu}m$) particles were separated using the solid separator and the solid separation rate was ranged from 66 to 453 g/min. The solid circulation rate increased as the gas velocity through the solid injection nozzle, solid height, and the number of solid intake holes increased. However, the effect of the fluidization velocity was negligible. Fine particle was circulated using the solid circulation system and the solid circulation rate was ranged from 65 to 390 g/min. We also proposed two interconnenced fluidized beds system for selective solid circulation equipped with the developed solid separator and the solid circulation system. Long-term operation of continuous solid circulation up to 20 hours has been performed to check feasibility of stable operation. The pressure drop profiles in two beds and the solid separation rate were maintained steadily, and therefore, we could conclude that solid circulation was smooth and stable.