• Transactions of the Korean hydrogen and new energy society
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• v.27 no.6
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• pp.712-720
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• 2016

When bioethanol and water are mixed at a proper ratio, phase separation can occur because of the immiscibility of biobutanol with water. Phase separation in bioethanol blends fuels is a major problem for gasoline vehicle users due to effect of octane number and component corrosion. Thus, in this study, the phase separation of bioethanol was examined effect of bioethanol blends (E3 (3 vo.% bioethanol in gasoline), E5 and E10) in presence of water. The effect were evaluated behavior with phase separation test, simulation test of fuel tank in gas station according to water addition volume and it was investigated change of water content, bioethanol content and octane number for gasoline phase in bioethanol blends (E3, E5 and E10) every 1 week after water addition. The E3 occurred phase separation more easily than the E5 and E10 in small water contents because solubility of water on ethanol content difference in gasoline-ethanol. It was kept a initial level of water content, bioethanol content, and octane number by repeated sample replacing in simulation test of fuel tank.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1933-1938
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• 2004

Nucleate boiling experiments with constant wall temperature of heating surface were performed using R113 for almost saturated pool boiling conditions. A microscale heater array and Wheatstone bridge circuits were used to maintain a constant wall temperature condition and to measure the heat flow rate with high temporal and spatial resolutions. Bubble images during the bubble growth were taken as 5000 frames a sec using a high-speed CCD camera synchronized with the heat flow rate measurements. The geometry of the bubble during growth time could be obtained from the captured bubble images. The bubble growth behavior was analyzed using the new dimensionless parameters for each growth regions to permit comparisons with previous results at the same scale. We found that the new dimensionless parameters can describe the whole growth region as initial and later respectively. The comparisons showed good agreement in the initial and thermal growth regions. The required heat flow rate for the volume change of the observed bubble was estimated to be larger than the instantaneous heat flow rate measured at the wall. Heat, which is different from the instantaneous heat supplied through the heating wall, can be estimated as being transferred through the interface between bubble and liquid even with saturated pool conditions. This phenomenon under a saturated pool condition needs to be analyzed and the data from this study can supply the good experimental data with the precise boundary condition (constant wall temperature).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.26-37
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• 2009

This paper suggests a sensor's placement method for detecting the dilemma zone problem when real-time driver's safety service is provided at signalized intersections by multiple pointed traffic sensors using USN environments. For detecting the dangerous situations from vehicles accelerating through yellow intervals, red-light running and stopping abruptly like as dilemma zone problem, VISSIM(microscopic, behavior-based multi-purpose traffic simulation program) is used to perform a real-time multiple detection situation by changing the input data like as various inflow-volume, design speed change, driver perception and response time. As a result, the optimal interval of traffic sensors is 20~27m, and the initialized sensor location from stop-line is different according to road design speed. Moreover, the pattern of detection about dilemma zone is also different according to inflow-volumes. This paper shows that the method is useful to evaluate the sensor's placement problem based on micro-simulation and the results can be used as the basic research for USN services.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.25-34
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• 2006

For decades, simulation technique has been well validated in areas such as computer and communication systems. Recently, the technique has been much used in the area of transportation and traffic forecasting. Several methods have been proposed for investigating complex traffic flows. However, the dynamics of vehicles and diversities of driver characteristics have never been considered sufficiently in these methods, although they are considered important factors in traffic flow analysis. In this paper, we propose a traffic simulation tool called Multi-Agent for Traffic Simulation with Vehicle Dynamics Model (MATDYMO). Road transport consultants, traffic engineers and urban traffic control center managers are expected to use MATDYMO to efficiently simulate traffic flow. MATDYMO has four sub systems: the road management system, the vehicle motion control system, the driver management system, and the integration control system. The road management system simulates traffic flow for various traffic environments (e.g., multi-lane roads, nodes, virtual lanes, and signals); the vehicle motion control system constructs the vehicle agent by using various vehicle dynamic models; the driver management system constructs the driver agent capable of having different driving styles; and lastly, the integrated control system regulates the MATDYMO as a whole and observes the agents running in the system. The vehicle motion control system and driver management system are described in the companion paper. An interrupted and uninterrupted flow model were simulated, and the simulation results were verified by comparing them with the results from a commercial software, TRANSYT-7F. The simulation result of the uninterrupted flow model showed that the driver agent displayed human-like behavior ranging from slow and careful driving to fast and aggressive driving. The simulation of the interrupted flow model was implemented as two cases. The first case analyzed traffic flow as the traffic signals changed at different intervals and as the turning traffic volume changed. Second case analyzed the traffic flow as the traffic signals changed at different intervals and as the road length changed. The simulation results of the interrupted flow model showed that the close relationship between traffic state change and traffic signal interval.

• Biomolecules & Therapeutics
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• v.7 no.3
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• pp.271-277
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• 1999

Safety evaluation of LB71350, a new HIV-1 protease inhibitor, was performed in mice, rats and dogs. For the general behavior of mice, LB71350 at an oral dose of 200 mg/kg did not show any significant effects on muscle tone and locomotor activity. In terms of central nervous system, at oral doses of 200 mg/kg and 1000 mg/kg, LB71350 inhibited acetic acid-induced pain response approximately 41% and 83% of control. respectively. At oral doses of 200 mg/kg and 500 mg/kg, it reduced the rectal body temperature in rats. Pentylenetetrazole-induced seizure in mice was slightly potentiated by oral administration of LB71350 at doses ranging from 200 mg/kg to 1000 mg/Ag. Single or five day treatment of LB71350 doubled the hexobarbital- induced sleeping time in mice at oral doses ranging from 50 mg/kg to 500 mg/kg. It did not cause any effects on gastric secretion and acidity in rat at oral doses of 200 mg/kg and 1000 mg/kg and also it did not change intestinal motility in mice up to 1000 mg/kg. Blood coagulation indices such as prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin time (TT) in rats were not affected by the treatment of LB71350 up to 500 mg/kg. LB71350 caused no significant effects on the cardiac output, stroke volume, heart rate, and mean blood pressure when infused intravenously to the anesthetized rats and dogs. Taken together, LB71350 at high oral doses caused significant pharmacological effects on the central nervous system and the hexobarbital-induced sleeping time.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.285-289
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• 1987

The partition behavior or proteins in an aqueous two-phase system of poly (ethyleneglycol)-potassium phosphate buffer (PEG/PPB) was investigated. The proteins of different surface hydrophobicity, i.e. Bovine serum albumin (BSA), ${\beta}-lactoglobulin$, ovalbumin. moved to the PPB-rich bottom phase in a PEG(12%)/PPB (12%) two-phase system resulting in very low partition coefficients. When the concentration of PPB increased to 15% level. the electric potential of bottom phase changed from +50 mV to zero and the partition coefficient tended to increase. The change In the molar ratio of $K_2HPO_4/KH_2PO_4$ in PPB from 1.43 to 9.55 caused the volume ratio of top to bottom phase $(V_t/V_b)$ to be decreased and protein partition coefficient increased. When the concentration of PPB was elevated from 14% to 26%, the $V_t/V_b$ decreased from 1.5 to 0.39 and the partition coefficient of proteins increased drastically; ${\beta}-lactoglobulin$ 74 fold. BSA 32 fold, ovalbumin 12 fold and lysozyme 5 fold.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.288-292
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• 2008

Dome shape design method of filament wound (FW) composite pressure vessel, which can create various dome shape with fixed boss opening, was suggested. And, the performance indices (PV/W) for composite pressure vessel with same boss opening but different dome shape were investigated by finite element analysis (FEA) and hydro-test. The FEA showed good agreement with test results for burst pressure. Generally, as the dome shape of pressure vessel was changed to flat dome, the inner volume is increased and the burst pressure is decreased. In the case of above ${\rho}_o$=0.54, the performance index showed decreased value due to the low burst pressure. However, at ${\rho}_o$=0.35, the dome shape change brings not significant reduction of burst pressure and performance index.

• Journal of the Korea Institute of Building Construction
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• v.21 no.2
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• pp.149-156
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• 2021

This study empirically verified whether aggressive order intake affect occurrence of defects of Korean construction companies. In order to compensate for the shortage of construction costs due to aggressive low-cost orders of contractors, self-response measures such as design changes are followed, and construction defects may be induced in this process. It aims to verify relevance between aggressive order intake and defect in construction empirically using financial accounting data. As a result, it was confirmed that an abnormal increase in order volume and a deterioration in profitability such as operating margin due to aggressive order taking behavior leads to a decrease in construction quality and occurrence of defects. In addition, it was also confirmed that low construction ability and intentional changes in construction design or contract conditions after construction commences were a direct causes of defects. The results of this study can serve as an opportunity to come up with measures to prevent defects by confirming the relationship between defects in construction and deterioration of profitability due to aggressive low-cost order takings.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.59-66
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• 2019

In this study, the effects of blast furnance slag cement and frost-resistant accelerator on shrinkage properties and shrinkage properties of mortar were examined. As a result, the addition of the frost-resistant accelerator to both OPC and BB has a small effect on the flash properties of mortar and the compressive strength increases from the early ages. In addition, when a frost-resistant accelerator is used in excess of the standard usage amount, it is necessary to examine the relationship of the expansion behavior at the early age, especially, between the compressive strength development and the expansion property. And it was confirmed that the addition of the frost-resistant accelerator tended to increase the shrinkage of mortar using the OPC and BB. With the addition of the frost-resistant accelerator, the amount of pores with a diameter of under the 30nm, especially, the amount of pores with a diameter of 20 to 30nm and the amount of pores with an ink-bottle decrease, and the shrinkage increases. And it is considered that a change in the amount this range of pores has a large effect on the shrinkage property.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.251-258
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• 2018

Recently, due to the increase in the traffic volume of vehicle, the collision of the vehicle collision has been increased so that the neck injuries of the passengers has been increased. In order to prevent this, vehicle collision analysis research using computer simulation has been actively carried out in consideration of the design point of car seat. In this study, I used the MADYMO program for analyzing the passenger behavior using a BioRID II dummy, and predicted the neck injuries of passengers according to the change of the backset at the rearward collision of the driving speed of 16km/h. As a result, it was found that the shorter the backset, the shorter the contact start time but the contact completion time was almost the same and the T1 acceleration showed that the acceleration increased with the backset. In addition, the tensile strength increases as the backset increases, and NIC (Neck Injury Criterion) increases as the head speed reaches the headrest.