• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.88-94
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• 2005

A swirl ratio of a charge in the cylinder could be calculated by measuring both the rotary speed of paddle and the intake air flow rate in the swirl measurement apparatus fur several positions of valve lift. The automation of the swirl ratio measurement for a cylinder head is achieved by controlling both the valve lift of cylinder head and a suction pressure of the surge tank, instead of controlling them manually. PID control of the surge tank pressure and positioning a valve lift of the cylinder head are also achieved by using two step motors, respectively. Rotating speed of a paddle are measured using an optical sensor and a counter. Flow rate are measured from ISA 1932 flow nozzle by reading a differential pressure gauge position using IEEE-1394 camera. Time to measure the swirl ratio for a port in the cylinder head is drastically reduced from an hour to 3 minutes by automation control of the apparatus.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.90-97
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• 2014

The effects of high pressure and low pressure exhaust gas recirculation (HP/LP EGR) portion on diesel engine combustion and emissions characteristics were investigated in a 2.2 L passenger-car diesel engine. The po3rtion of HP/LP EGR was varied from 0 to 1 while fixing the mass flow rate of fresh air. The intake manifold temperature was lowered with the increasing of the portion of LP EGR, which led to the retardation of heat release by pilot injection. The lowered intake manifold temperature also resulted in low nitrogen oxide (NOx) emissions due to decreased in-cylinder temperature and prolonged ignition delay, however, the carbon monoxide (CO) emission showed opposite trend to NOx emissions. The brake specific fuel consumption (BSFC) was decreased as the portion of LP EGR increased due to lowered exhaust manifold pressure by wider open of turbocharger vane. Consequently, the trade-off relationship between NOx and BSFC could be improved by increasing the LP EGR portion.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.295-307
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• 1988

In order to predict performance of the intake manifold, which is dependent on the length and diameter of a resonance pipe, the Fluid Dynamic Model for 4-cylinder diesel engine is developed using two step Lax-Wendroff method to solve the governing equations of air flow in the intake system. Boundary conditions at the intake valve, branch at the manifolds, and pipe end are also modeled. The results of the models are compared with the experimental results of a motored engine. The model is capable of predicting the real phenomena satisfactorily with reasonable computing time.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.81-85
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• 2009

In this paper, the aerodynamic shape of air intake was investigated for the efficient cooling of electronic equipments in aircraft pod. As a first step, ESDU method was applied for the basic shape design of air intake considering the operational environments. The second step was to confirm the performance on design point, so the internal flow field of air intake was analyzed using a commercial Navier-Stokes code(FLUENT). And also the aerodynamic characteristics of internal flow at off-design condition was investigated with the variations of airflow rate. The results show that the air intake meets the requirement of target performance under the mission environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.22-31
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• 1993

Spark-ignition engine knock is affected by engine operating conditions such as engine speed, spark timing and intake air temperature. In this study the effect of intake air temperature on knock characteristics was studied experimentally using a 4-cylinder carburetor spark-ignition engine. The cylinder pressure data at 2000rpm were taken for intake air temperature range of $30^{\circ}C$ to $80^{\circ}C$ with $10^{\circ}C$ interval. And 80 consecutive cycles were taken at each experimental condition. As the same spark timing, as the intake air temperature increased by $50^{\circ}C$, the mean knock intensity increased about 20kPa. This effect corresponds to that of spark timing advance of 3 crank angle degrees.

• Journal of ILASS-Korea
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• v.21 no.1
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• pp.7-12
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• 2016

In this study, to research in-cylinder flow characteristics of spark-ignited engine with intake valve closing timing change for Miller cycle. 3D simulation study were used 6 different intake valve profile with $CAD10^{\circ}$ gap for retard intake valve closing timing. Comparison of In-cylinder flow pattern characteristic were accompanied between Base and LIVC. And the efficiency of volume and the work of compression were analyzed with simulation study. When intake valve closing angle was retarded in $CAD50^{\circ}$, the pressure in cylinder was decreased about 12~13 bar and volume efficiency was reduced about 16%. The efficiency of volume and the work of compression were reduced on LIVC.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.5
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• pp.637-648
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• 2011

This study was designed to investigate the relationship between the nutrient intakes, antioxidants, and inflammatory markers of overweight and obese adults (46 females and 16 males) in Yeongdong area. The study was conducted through questionnaires, anthropometric checkups, 2-day 24 hr recalls and blood biomarker analyses. Body fat was significantly higher in women compared to men. Diastolic blood pressure (DBP) and systolic blood pressure (SBP) were significantly higher in men compared to women. There were no significant differences in height, weight, body mass index, and waist size among the two groups. The intake of nutrients was significantly higher in men compared to women. Ferric reducing ability plasma (FRAP) was significantly higher in men compared to women. Body fat was positively associated with blood IL-6 and IL-8 levels. DBP was positively associated with FRAP. The intake of protein was negatively associated with IL-6 levels. The intake of carbohydrates was negatively associated with total antioxidant capacity (TAC). Prostaglandin E2 (PGE2) levels were negatively associated with TAC. These results suggest that antioxidant and inflammatory markers may be related to the body fat percentage and dietary intake in overweight and obese adults.

• Korean Journal of Community Nutrition
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• v.6 no.2
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• pp.130-138
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• 2001

This study investigated the effect of taste preference(sweet, sour, salty, hot) on anthropometric measurements and nutrient intakes of 256 primary school children in Kwangju. There was no significant difference in the anthropometric measurements according to the sweet taste preference. Height, weight, triceps, abdomen, and chest circumferences of the group preferring a sour taste, however, were significantly lower than those of the other groups. The height of the group preferring a salty taste was significantly shorter than that of the other groups and there was a tendency toward high systolic blood pressure and diastolic blood pressure. The waist circumference of the group not preferring the hot taste was larger than those of the other groups. There was no significant difference in the energy intake according to the sweet taste preference. The protein intake of the group preferring a sweet taste as significantly lower than that of the other groups. The fiber intake of the group preferring a sour taste was significantly higher than that of the other groups. There were no significant differences in the nutrient intakes according to the salty taste preference. The energy intake of the group preferring a hot taste was lower than that of the other groups. The results show that children's taste preferences influence anthropometric measurements and nutrient intakes. These results suggest that children's eating behaviors are in needs of correction. The findings of this study should be applied to nutrition education to ensure better physical fitness of children.

• Korean Journal of Community Nutrition
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• v.1 no.1
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• pp.79-88
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• 1996

This study was conducted to assess nutritional status of the elderly from low-income urban area and to investigate environmental and health risk factors that may influence to nutrient intakes. One hindered eighty three(males 53, females 130) healthy homestaying subjects aged over 65 years in Seoul were assessed with anthropometric measurements and dietary intake in August, 1994. HT and BW for females were decreased with aging. The proportion of hypertension was 36% with indite of $SBP{\;}(SBP{\;}{\gg}{\;}160mmHg)$ and 52% with indice of DBP $(DBP{\;}\gg{\;}97mmHg)$. Distribution of BMI, OR and PIBW indicated that BMI was more sensitive for identifying underweight whereas PIBW was more sensitive for identifying overweight. for group aged over 75, males had significantly lower intake of energy, protein, fat, calcium, iron, vitamin A and $\beta$ carotene compared to the group aged 67~74, while females had lower intake of calcium and vitamin A. Elderly group with smoking, less familly size and living alone had lower nutrient intakes. Blood pressure in the elderly subjects did not influence to nutrient intakes, except elderly with normal blood pressure were taking increased amount of thiamin and niacin.

• The KSFM Journal of Fluid Machinery
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• v.3 no.4 s.9
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• pp.52-58
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• 2000

The numerical study on the waterhammer was carried out for the intake pumping station of the metropolitan water supply 6th stage project. Because the waterhammer problems as a result of the pump power failure were the most important, these situations were carefully investigated. The surge tank and the stand pipes effectively protected the tunnels md the downstream region of pipeline from the pressure surge. In case the moment of inertia of the pump and motor was above $5080\;kg{\cdot}m^2$, the column separation did not occur in the pipeline between the pumping station and the inlet of 1st tunnel. As the moment of inertia increased, the pressure surges decreased in the pipeline conveying raw water. The pump control valve was chosen as the main surge suppression device for the intake pumping station. After power failure, the valve disc should be rapidly closed in 2.5 seconds and controlled the final closure to 15 seconds by the oil dashpot. If the slamming happened to the pump control valve, there was some danger of this system damaging. As the reverse flow through the valve increased, the upsurge extremely increased.