• Journal of Power System Engineering
• /
• v.19 no.4
• /
• pp.82-88
• /
• 2015

The purpose of this study is to investigate the effect of the impinging plate on combustion process in Diesel engine. Especially, the variation of exhaust emission and engine performance by the change of fuel injection timing and fuel injection pressure between the trial engine with impinging plate and the prototype engine were examined. The nitrogen oxide concentration of the trial engine decreased more than 50% compared to the prototype engine, however, smoke concentration of the trial engine indicated higher degree than the prototype engine. The smoke concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection timing become faster, whereas the nitrogen oxide concentration decreased as the fuel injection timing is retarded. The nitrogen oxide concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection pressure become lower. But smoke concentration decreased as the fuel injection pressure become higher.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.983-988
• /
• 2004

In the present study, the effects of orthogonal ribs on structural warpage during injection molding process were investigated. Basic ribbed models for the evaluation of degree of warpage were introduced and designed. Injection molds for these models are manufactured based on the full 3D CAD/CAM technology and specimens are prepared for experiment. Numerical analysis using commercial plastic injection molding analysis software was also performed to compare the results with experimental ones. The variations of materials and parameters such as injection time, mold temperature, melt temperature, holding time were considered in the present work. It was shown that orthogonal ribs have significant effect on the reduction of warpage during the injection molding process.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2965-2970
• /
• 2008

Effects of split injection and oxygen-enriched air on soot emissions in a DI diesel engine were studied by the KIVA-3V code. When split injection is applied, the second injection of fuel into a cylinder results in two separate stoichiometric zones which increases soot oxidation. As a result, soot emissions are decreased with split injection. When oxygen-enriched air is applied together with split injection, higher concentration of oxygen helps secondary combustion which results in a higher temperature in the cylinder. The increased temperature promotes growth reaction of acetylene with soot but doesn't improve the acetylene formation during the second injection of fuel. As more acetylene is consumed in the growth reaction of acetylene, the net acetylene mass in the cylinder is decreased, which leads to a decrease of soot formation. With an increase of soot oxidation caused by split injection, the soot emissions are decreased significantly. However, to avoid excessive NOx emissions with increased oxygen concentration, the level of oxygen concentration should be lower than 22% in volume.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.5
• /
• pp.15-21
• /
• 2003

The liquid phase LPG injection engine is a new technology to make good use of LPG as a clean energy. However, it is difficult to precisely control air/fuel ratio in the system because of variation of fuel composition, change of temperature and flash boiling injection mechanism. This study newly suggests an injector control logic for liquid phase LPG injection systems. This logic compensates a number of effects such as variations of density, stoichiometric air/fuel ratio, injection delay time, injection pressure, release pressure which is formed by flash boiling of fuel at nozzle exit. This logic can precisely control air/fuel ratio with only two parameters of intake air flow rate and injection pressure without considering fuel composition, fuel temperature.

• Journal of Biomedical Engineering Research
• /
• v.22 no.3
• /
• pp.303-309
• /
• 2001

It is well known that the electrical impedance of biological tissues is very sensitive to their temperature. In this paper, we have analyzed the effects of temperature change on the phase of magnetic resonance images obtained with external current injection. It has been found that the local phase in the current injected magnetic resonance image can be changed noticeably when local temperature change appears at a part of the tissue. At the experiments with a 0.3 Tesla MRI system, we observed the local phase changes at the phantom images when the phantom temperature was varied between 25 -45$^{\circ}C$. We think that the current injection MRI technique can be used for in-vivo monitoring of the temperature inside biiological tissues if the relation between the local temperature and phase can be quantified.

• Journal of Oral Medicine and Pain
• /
• v.19 no.2
• /
• pp.137-151
• /
• 1994

In order to evaluate objectively the anxiety level in dental treatment, the author used Biotrainer(BF-120R), one of the skin temperature biofeedback apparatus, to examine 68 dental outpatients on their digital skin temperature change due to routine consecutive dental procedures(oral examination, anesthetic injection, cavity preparation, fissure sealing, polishing). The subjective anxiety level change was also evaluated by visual analog scale. The obtained results were as follows : 1. The skin temperature decreased through consecutive procedures and the temperature in each procedure decreased until 60sec, and then increased on 120sec. 2. The temperature changes in Preparation and Injection were greater than those in other procedures. 3. Generally, male exhibited more change of skin temperature in all procedures than female. 4. Type II, continuously decreasing after procedure, occupied the most in all patients and yhad the lowest beseline temperature. 5. The anxiety level of before-procedure was higher than that of after-procedure and the levels in Injection and Preparation were higher than in other procedures.

• Korean Journal of Clinical Pharmacy
• /
• v.8 no.1
• /
• pp.54-58
• /
• 1998

The stability of ceftriaxone sodium 100 mg/ml in the water for injection was tested at two temperature conditions (refrigerator and room temperature) and two storage containers (vitro and syringe). The stability of each sample was determined by high-performance liquid chromatography while storing for 5 days at room temperature and 27 days at refrigerator. The concentration of ceftriaxone sodium was 100 mg/ml which the hospital usually use as a filling preparation for I.V. push or Y-site injection. There was no significant difference between the storage in vials and syringes. There was no significant difference in the change of concentration until storing the reconstituted ceftriaxone sodium injection for 2 days at room temperature and 14 days at refrigerator. In conclusion, the ceftriaxone sodium 100 mg/ml in the water for injection can be stored in vial or syringe for 2 days at room temperature and 14 days at refrigerator after preparation.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.12 no.4
• /
• pp.201-202
• /
• 2008

Because of the importance of suction or injection in the fields of aerodynamics, space science and many other industrial applications, our present study is motivated. The effect of natural convection on MHD flow past a vertical plate with suction or injection is studied. We have tried to solve the dimensionless governing equations by using finite difference scheme. To ensure the validity of our numerical solutions, we have compared our numerical solutions for temperature and velocity for the case of suction and injection for unit Prandtl number with the available exact solutions in the literature. The corresponding codes were written in Mathematica 5.0 for calculating numerical solutions for temperature and velocity and the comparison between the exact and numerical solutions. For the purpose of discussing the results some numerical calculations are carried out for non-dimensional temperature T, velocity u, skin friction ${\tau}$ and the Nusselt number $N_u$, by making use of it, the rate of heat transfer is studied.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.3
• /
• pp.1-9
• /
• 2004

During the SI engine starting up, starting conditions directly contribute to the unburned hydrocarbon emissions in spark ignition engines. The effects of catalyst temperatures and fuel injection skip methods on HC emissions were investigated. The test was conducted on a 1.5 L, 4-cylinder, 16 valve, multipoint-port-fuel-injection gasoline engine. To understand the formation of HC emissions, HC concentration was measured in an exhaust port using a Fast Response Flame ionization Detector (FRFID). The result showed that HC emissions, which were emitted at the cold coolant and catalyst temperature, were generated much higher than those of hot coolant and catalyst temperatures. In additions, fuel injection skips reduced highly HC emissions. It is convinced that optimized fuel injection skip method according to coolant and catalyst temperatures could be applied to reduce HC emissions during the SI engine starts.

• Transactions of Materials Processing
• /
• v.15 no.1 s.82
• /
• pp.15-20
• /
• 2006

The rapid thermal response (RTR) molding is a novel process developed to raise the temperature of mold surface rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly to the ejection temperature. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filling difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. In order to take into account the effects of thermal boundary conditions of the RTR mold, coupled analysis with transient heat transfer simulation is suggested and compared with conventional isothermal analysis. The proposed coupled simulation approach based on solid elements provides reliable thin wall flow estimation for both the conventional molding and the RTR molding processes.