• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.133-137
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• 2007

An experimental study is conducted to evaluate and compare the use of BiodieseDI Fuel supplements at blend ratio of 10/90(BDF10) and 20/80(BDF20), in four stroke, direct injection diesel engine located at the authors' laboratory. especially this Biodiesel is produced from Rape oil at the authors' laboratory. The tests are conducted using each of the above fuel blends, in the engine working at a speed of 1800rpm and at a various loads. In each test, specific fuel consumption, exhaust emissions such as nitrogen oxides(NOx), carbon monoxide(CO) and Soot are measured. The results of investigation at various operating conditions are as follows (1) Specific fuel consumption is increased average 1.52%, maximum 1.84% at load 25% in case of BDF10, and average 1.98%, maximum 2.80% at load 25% in case of BDF20. (2) CO emission is decreased average 5.14%, maximum 6.09% at load 0% in case of BDF10, and average 7.75%, maximum 9.13% at load 0% in case of BDF 20. (3) NOx emission is increased average 2.97%, maximum 3.74% at load 0% in case of BDF10, and average 3.84%, maximum 4.67% at load 0% in case of BDF20. (4) Soot emission is decreased average 9.36%, maximum 10.85% at load 75% in case of BDF10, and average 11.99%, maximum 13.95% at load 75% in case of BDF20.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.157-163
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• 2020

Recently, fine dust has been known to cause cardiovascular diseases here, raising interest in ways to reduce emissions by efficiently using fuel from cars that cause air pollution. Accordingly, a driving assistance system was developed to save fuel by eco-driving and improve the driver's bad driving habits. The system was developed using raspberry pi, arduino and Android. Using RPM, speed, fuel injection information obtained from OBD-II, and gyro-sensor values, Fuel-Cut is induced to create an optimal inertial driving environment. It also provides various information system such as weather, driving environment, and preventing drowsy driving through GUI and voice recognition functions. It is possible to check driving records and vehicle fault information using Android application and has low overhead for message transmission using MQTT protocol optimized for IoT environment.

• Journal of Energy Engineering
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• v.18 no.2
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• pp.87-92
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• 2009

An experimental investigation is conducted to study a 2-phase vertically upward hydraulic transport of solid particles by water and non-Newtonian fluids in a slim hole concentric annulus with rotation of the inner cylinder. Rheology of particulate suspensions in viscoelastic fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study, a clear acrylic pipe was used in order to observe the movement of solid particles. Annular velocities varied from 0.3 m/s to 2.0 m/s. The mud systems included fresh water and CMC solutions. Main parameters considered in the study were inner-pipe rotation speed, fluid flow regime and particle injection rate. A particle rising velocity and pressure drop in annulus have been measured for fully developed flows of water and of aqueous solutions. For both water and 0.2% CMC solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.54-61
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• 2000

Recently, our circumstances are threatened by an accident that leakage of under ground storage tank and illegal dumping of synthetic organic compounds at chemical plants and many treatment methods, Activated carbon adsorption, Ozonization, Membrane filtration and Photocatalystic oxidation, are developed to remove such a synthetic organic compounds. And it has reported that Activated carbon adsorption have a great removal efficiency to nondegradable matters and organic compounds which have a high molecular weight. Comparing with other adsorbents, Activated carbon adsorption have a worse efficiency when ad desorption speed is low. Thus improved type of adsorbents was invented and one of those is Activated Carbon Filter. The purpose of this study was getting information about adsorption characteristic phenol which can be applied Activated Carbon Fiber and Granular Activated Carbon. In detail, With comparing removal characteristics of phenol in the presence Humic Acid using Activated Carbon Fiber(ACF) and Granular Activated. Carbon(GAC), it is to certify an effective application of Activated Carbon Fiber. At the range of this study, Batch test, Isotherm adsorption test and Factorial analysis, following conclusion were obtained from the results of this study. Batch test was carried to know time of adsorption equilibrium. In this study about time of adsorption equilibrium by ACF was faster than GAC's, for developed micropore of ACF. From the result of phenol adsorption test, High removal rate of adsorption is shown at pH 5. The result of lsotherm adsorption test, it has represented that the Freundlich's isotherm is most suitable one in others, that a ACF's adsorption capacity is more excellent than GAC's. Adsorption of phenol exiting humic acid is decreased getting raised humic acid concentration. Since ACF's micropore is developed at this time, an effect of high molecular humic acid is lower. Factorial analysis was carried to know about Main effect which was injection dosage of adsorbent in the range of this study.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1050-1056
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• 2010

Diesel engines introduce only air into the cylinder, and the air is high lycompressed. Fuel is directly injected into the combustion chamber in high temperature and pressure. Therefore diesel engines have high thermal efficiency because of the high compression ratio, while having high level of particulate matter and nitrogen oxide emissions because of the direct fuel injection. Many technologies have been developed to reduce particulate matter and nitrogen oxide emissions from diesel engines. One of the technologies is hydrogen fuel introduced into the combustion chamber with diesel fuel. In this thesis tiny amount of hydrogen is supplied into the combustion chamber in order to enhance the combustion performance. The engine, in which hydrogen is introduced, is tested. There are 20 test conditions given as 5 torque values of 100%, 75%, 50%, 25%, 0%, and 4 engine speeds of 700rpm, 1000rpm, 1500rpm and 2000rpm for the two cases with or without hydrogen addition. Maximum torques and Idle torques at each engine speed are measured, then the torque values are divided into 4 levels with 25% increasing step. The result shows that the fuel consumption, smoke, CO are reduced while the NOx emission is slightly increased, and the hydrogen addition has not a great effect on the performance at low loads but a great effect at a maximum load.

• Journal of Korea Foundry Society
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• v.14 no.5
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• pp.471-479
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• 1994

Al-2%Si-2%Mg alloy containing SiC particle in 20, $70{\mu}m$ were prepared by mean of squeeze casting with various pressure 50, 100, 150 and 220MPa respectively. The specimens were made by casting into $50{\Phi}{\times}100{\ell}$ mold under various squeeze conditions(pressures, pressurizing temperature, particle sizes). Mechanical properties(hardness, tensile strength, elongation and wear characteristics) were evaluated at room temperature with those various fabrication factors. It became feasible to make favorable Al-SiCp composite free from casting defects by the injection of Ar gas during melting and 100MPa pressure squeeze casting. However, pressure of 50MPa was not sufficient to avoid completely porosity formation as a result of precessing and shrinkage during solidification. As the particle size is smaller and the squeeze pressure is higher, the hardness and tensile strength at room temperature are higher. Cell size became smaller gradually with increase of squeeze pressure. With increase of squeeze pressure(MPa), wear behaviors of those composites were changed from adhesive into abrasive wear, and the tendency of above behavior became outstanding with increasing sliding speed. The chemical reaction(4Al＋3SiC${\rightarrow}$$Al_4C_3+3Si$) is more accelerated at interface between SiCp and matrix with increase of squeeze pressure. Therefore $Al_4C_3$ intercompound and Si peak intensity is increased at interface.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.156-165
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• 2014

This paper is the first investigation on the effect of flow control methods on the part load performance in a spark ignition engine. For comparison of the methods, two control devices, port throttling and masking, were applied to a conventional engine without any design change of the intake port. Steady flow evaluation shows that steady flow rates per unit opening area and swirl ratio are very low compared with the port throttling and saturated from mid-stage valve lift, however, swirl increases slightly as the lift is higher in case of 1/4 masking control. In the part load performance, the effect of simple port throttling on lean misfire limit expansion is limited and insufficient; on the other hand a masking improves the limit considerably without any port modification for increasing swirl. Also the results show that the intake flow control improves the combustion with following two mechanisms: stratification induced by the combination of the flow pattern and the fuel injection timing attribute to ignition ability and the intensified flow ensure fast burn. In addition fuel consumption reduces under the flow controls and the reduction rate is different according to the operation conditions and control methods. At the Stoichiometric and/or low speed and low load the throttling method is more advantageous; however vice versa at lean and high load condition. Finally, the throttling is more efficient for HC reduction than masking, on the other side the NOx emissions increase under the masking and decrease under the port throttling compared with conventional port scheme.

• The Korean Journal of Pain
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• v.8 no.1
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• pp.37-42
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• 1995

The intermittent injection of analgesics is a inadquate method for postoperative pain control. Recently a non-electroic, disposable and portable infusor (Boxter Two Day $Infusor^R$) has been developed which can deliver analgesics with 2 ml/h speed continuousely. The present study examined the effects of three methods of pain management on recovery in 306 patients undergoing elective surgery in Wonkwang University Hospital. Group 1 (n=106) received i.m. $Valentac^R$ on a PRN basis. Group 2 (n=100), initial 2 mg of bolus morphine was followed by 48 mg of continuous infusion. Group 3 (n=100), initial 2 mg of morphine followed by morphine 18 mg-ketorolac 120 mg. We evaluated an analgesic efficacy with NRS (numerical rating scale) at 12, 24, 36, 48, 60 and 72 hours after the operation. The side effects (nausea, vomiting, pruritus, sedation and respiratory depression) were evaluated. In group 1, we asked major concern before operation and efficacy of pain control with pain severity (no pain, mild pain, moderate pain, sever pain). The results were as follows: 1) Major concern before operation is pain (40%). 2) 53% of patients suffered pain in group 1. 3) Morphine and morphine-ketorolac infusion groups were superior to the i. m. ($Valentac^R$) group with respect to postoperative analgesia. 4) In group 3 (morphine-ketorolac), there was no pruritus and mild nausea and vomiting.

• Korean Journal of Digital Imaging in Medicine
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• v.16 no.1
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• pp.27-33
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• 2014

The purpose of this study evaluated the hemo-dynamic information within 30 seconds clinically in 3D breast MRI. From January to March 2014, A total of 40 people were examined at 1.5 Tesla(Philips, Medical System, Achieva, The Netherlands) MRI equipments using 16 channel SENSE breast coil. The imaging parameters on vibrant are fellow as: $TR/TE/FA^{\circ}$/Matrix size/Slice thickness/Slab($5ms/2ms/10^{\circ}/180{\times}139{\times}2mm/80$). This study used a Gadovist and injected it with injection speed of 4 ml /sec by auto injector with 15 ml saline flushing. Firstly, for the delay time study, it divided three different delay time from immediately, 20 seconds, and 30 seconds. In quantitative analysis, the ROI signal intensities of tumor and surrounding tissues were measured retrospectively. In qualitative analysis, the image quality was scored from 1 to 5 point by one experienced radiological technologists as a visual test. The significance level of each delay time was evaluated with a one-way ANOVA(p<0.05). In the visual test, score levels on 30 seconds delay time was a little bit higher than others(p<0.05). The signal intensity of the tumor were $1445{\pm}360$, $1410{\pm}320$, $1510{\pm}415$ on immediately, 20 seconds, and 30 seconds and score levels were $4.18{\pm}0.85$, $3.54{\pm}0.94$, $4.45{\pm}0.74$(p<0.05). The data on immediate images showed better results than that others(p<0.05). Conclusively, Although it has been high scored in 30sec delay time for visual test in order to avoid failure in 20second, 30seconds delay time after contrast media administration, we recommend that the DCE 3D breast MRI commence immediately.

• The KSFM Journal of Fluid Machinery
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• v.10 no.6
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• pp.32-37
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• 2007

Aerodynamic forces and moments have been used to control rocket propelled vehicles. If control is required at very low speed, Those systems only provide a limited capability because aerodynamic control force is proportional to the air density and low dynamic pressure. But thrust vector control(TVC) can overcome the disadvantages. TVC is the method which generates the side force and roll moment by controlling exhausted gas directly in a rocket nozzle. TVC is classified by mechanical and fluid dynamic methods. Mechanical methods can change the flow direction by several objects installed in a rocket nozzle exhaust such as tapered ramp tabs and jet vane. Fluid dynamic methods control the flight direction with the injection of secondary gaseous flows into the rocket nozzle. The tapered ramp tabs of mechanical methods are used in this paper. They installed at the rear in the rocket nozzle could be freely moved along axial and radial direction on the mounting ring to provide the mass flow rate which is injected from the rocket nozzle. In this paper, the conceptual design and the study on the tapered ramp tabs of the thurst vector control has been carried out using the supersonic cold flow system and schlieren system. This paper provides the thrust spoilage, three directional forces and moments and distribution of surface pressure on the region enclosed by the tapered ramp tabs.