• Journal of the Korean Society of Propulsion Engineers
• /
• v.26 no.1
• /
• pp.77-87
• /
• 2022

In order to perform the scramejt engine intake ground test using the Scramjet Engine Test Facility(SETF) of the Korea Aerospace Research Institute. we introduced the test availability check procedure that is generally conducted. The design process of the newly manufactured Mach 5 nozzle for the scramjet intake test was summarized, a device for checking the core flow distribution of the nozzle was explained, and the core flow test analysis results were written. Through a series of test results, it was confirmed that the intake was located in the new Mach 5 nozzle core.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.934-939
• /
• 2001

In computational study of the flow in piston engines and the flow through moving valves, the use of moving vertices is essential for modelling flows with moving boundaries. The positions of cell vertices in such cases must be allowed to vary with time. To simulate 3-dimensional port-valve and piston-cylinder of HIMSEN 6H21/32 engine, a commercially available code, STAR-CD, was used. Changes in mesh geometry was specified by PROSTAR commands.(i.e. the Change Grid operation in the EVENTS command module.) Control of the intake flow is expected to play an important role as designers seek to obtain better fuel spray characteristics, fuel mixing and mixture preparation, combustion performance, and emissions reductions to meet national standards. As a result of analysis, velocity fields indicate the presence of a structured flow comprised of one pair of counter-rotating vortices under the intake valve during the early induction process. These flow structures remain visible for most of the intake process. As the piston moves towards BDC, these vortices develops into a larger tumbling motion that dominates the flow structure.

• Journal of the East Asian Society of Dietary Life
• /
• v.15 no.1
• /
• pp.1-10
• /
• 2005

Dietary behavior, body mass index(BMI) and nutrient intake status of 185 boys and 205 girls in 3rd grade middle school students in Daegu area were analyzed. Boys were 168.6cm tall and weighed 61.3kg on the average and girls 158.5cm and 54.4kg, respectively. From their BMIs, 17.9% were classified as the underweight, 54.2% as the average, 14.7% as the overweight and 13.2% as the obesity. The average energy intake per day was 2222.6 kcal for boys, 1796.2 kcal for girls which were 83.3% and 86.6% of the RDA, respectively. Composition rate of carbohydrate, protein, fat in relation to energy intake was 62.4 : 16.5 : 21.1 for boys and 58.8 : 16.0 : 25.2 for girls. Protein was taken low and carbohydrate and fat were high in this study. Particularly, fat intake rate of girls was high. Calcium, iron, vitamin A, and vitamin B2 did not meet the RDA and especially calcium was taken 63.9% for boys and 54.01 % for girls. Most of the students have tendency to eat irregularly and to overeat. For the nutrients intake, calories and calcium intake were lower than the RDA regardless of gender and iron intake was not enough for girls only. In relation to BMI, obesity group students were taking lower calories and proteins than the normal students were. No consistent trend was shown for boys about nutrient intake in relation to eating speed. Students had a correct perception of their body image which was similar to that of their mothers. Nutrient average intake is under the average and the percentile under 70% of RDA was high contrary to the fact that nutrient intake like calcium and iron was exceedingly important particularly in the growth process. Therefore, nutritional education for the proper intake of nutrients was required for the students in Daegu area. Especially, education has to be focused on the balanced diet and correct food choices for the proper dietary behaviors.

• Journal of Nutrition and Health
• /
• v.43 no.6
• /
• pp.597-606
• /
• 2010

This study investigates the change of level of psychosocial factors of decisional balance, processes of change, and self-efficacy after nutrition education on vegetable and fruit intake of children in pre-action stages. Forty-seven 5th grade elementary school children in Yeongi-Gun, Chungnam-Do were categorized into pre-action stages from a total of 71 children by four-stage questions, and then finally into two stages of precontemplation and contemplation & preparation. After 6 weeks nutrition education, recognition of both of pros and cons of vegetable intake were improved in the two groups of precontemplation and contemplation & preparation. In fruits intake, however, recognition of pros was not changed after nutrition education in either stage, but recognition of cons was improved only in the precontemplation stage. However, no difference in any psychosocial variables was found between precontemplation stage and contemplation & preparation stage. After the nutrition education, the score of consciousness raising of vegetable intake belonging to cognitive process of change increased in the subjects of the precontemplation stage, wheres the scores of dramatic relief, self-reevaluation, environment reevaluation and social liberation increased in the group of contemplation & preparation. In fruit intake, however, no change was found except in the environment reevaluation in the precontemplation group. The behavioral process of change of vegetable and fruit intake did not show any change in either group after nutrition education. Self-efficacy scores of vegetable intake of keeping the foods at hand, eating the recommended number of servings and making time to eat increased in the precontemplation group, while in the contemplation & preparation group, self efficacy scores of shopping for a variety of vegetables, instead of keeping the foods at hands, as well as the scores of the rest two items of eating the recommended number of servings and making time to eat increased after nutrition education. However, in case of fruits intake, no difference was shown in the precontemplation stage except an item of keeping the foods at hand. The results indicated that the stage of change was progressed in the pre-action stage after nutrition education and the scores of many psychosocial factors increased in both pre-action stages. It is suggested that the recognition of cons as well as the cognitive process of change and self-efficacy could be best used as indicators of the assessment of nutrition education program for vegetable intake.

• Korean Journal of Community Nutrition
• /
• v.8 no.2
• /
• pp.160-170
• /
• 2003

Pregnant women in South Korea are a highly risk group fur iron deficiency anemia. Previous studies indicated that the 24-hour recall method was insensitive in distinguishing iron deficiency anemic women from normal women. This method is also impractical to when used at community health centers where no public health dietitians are employed. The objective of this study was to develop a convenient tool to evaluate the usual iron (Fe) intake of pregnant women. The study participants were 115 pregnant women (age 23 to 37 years) at gestational stage of 13 to 24 weeks. Anemic subjects were classified on the basis of their serum ferritin < 12.0 ${\mu}$g/L and hemoglobin < 12.0 g/dL levels. Food frequency questionnaires with 46, 29, and 15 commonly consumed food items were used to measure the usual intake of iron of the subjects. Hemoglobin and serum ferritin were measured from fasting blood samples. Nutrients intake was assessed on three consecutive days using the 24-hour recall method and the food record method. The iron index score calculated using the food frequency method showed a significantly positive correlation with iron intake for the three days dietary intake. The iron index showed a significantly difference (p < 0.05) between the normal and anemic groups. However, there was no significant difference in the iron intake between the anemic and the normal women as measured by the 24-hour recall and food record method. Our study indicated that the 29-food items questionnaire could be used as a screening tool to identify poor dietary intake of iron. (Korean J Community Nutrition 8(2) : 160170, 2003)

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.1
• /
• pp.51-58
• /
• 2002

A simulation model has been developed to predict the performance of 5-valve gasoline engine by gas exchange process with combustion model. In this study, we simulated the intake flow characteristics and performance of 5-valve engine with entwine speed and we compared the 5-valve engine performance with that of 4-valve engine. As a result. the calculated value was in consistency with the measured value relatively. The performance of 5-valve engine was higher than that of 4-valve engine in high engine speed region.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.930-931
• /
• 2011

As the upsurge in oil prices and global warming, Energy saving is needed to overall industry. If The head of Intake gate screen is high. The pumping process involves a loss of energy and results in high emissions of greenhouse gases. Therefore, blockages in intake gate should be free. Another advantage of cleaning is stabilizing pumping system. Because vibration and cavitation decreases when loss of head is low.

• Journal of Nutrition and Health
• /
• v.34 no.1
• /
• pp.98-111
• /
• 2001

The article demonstrates a method of studying human health and nutrition by applying a multi-disciplinary approach and examines how humans developed and survived by adjusting to their environment. This process involves physiological, cultural and genetic adaptation both independently and interactively. This study postulates that a sound human health may be the result of balance between nutrition and environmental conditions. It is noted that there is a positive correlation between malaria and fava bean intake, and sickle cell anemia and cassava intake. It is also suggested that the difference in disease structure in soybean and non-soybean consumption cultures can be explained by an ecological approach to studying nutrition. This study further suggest that the relationship between nutrition and socio-cultural system. epidmiological study of nutrition and cultural environment nutrition and conceptual characteristics, nutrition and food intake pattern, nutrition and health sociological functions and the physioloical, cultural and genetic adaptation can all be stimulating research subjects to be studied form and ecological point of view. This article also includes the results from a series of ecological studies conducted by the author investigating the relationship between nutritional status of Korean breast-feeding mothers and the composition of the human milk and also the Vitamin D status of Korean and their lifestyle. (Korean J Nutrition 34(1):98-111, 2001)

• Journal of Advanced Marine Engineering and Technology
• /
• v.18 no.2
• /
• pp.97-103
• /
• 1994

This paper describes briefly the simulation program for predicting the performance of a high speed turbocharged four cycle diesel engine. The wave phenomena in the intake and exhaust systems are calculated by the characteristic method. The combustion process in the power cycle is represented by the heat release pattern which is given by the Wiebe's function or the pattern based on measured values. Turbocharger matching for the engine is described by utilizing the characteristic maps of both the compressor and turbine, which are obtained from quasi-steady states. A comparison of experimental and calculated results shows a good agreement. Then the influences of the intake system, the period of valve overlap and the characteristics of the turbine are numerically investigated by the simulation.

• Journal of Mechanical Science and Technology
• /
• v.15 no.1
• /
• pp.108-116
• /
• 2001

The in-cylinder flow field of gasoline engine comprises unsteady compressible turbulent flows caused by the intake port, combustion chamber geometry. Thus, the quantitative analysis of the in-cylinder flow characteristics plays an important role in the improvement of engine performances and the reduction of exhaust emission. In order to obtain the quantitative analysis of the in-cylinder gas flows for a gasoline engine, the single-frame particle tracking velocimetry was developed, which is designed to measure 2-dimensional gas flow field. In this paper, influences of the swirl and tumble intensifying valves on the in-cylinder flow characteristics under the various intake flow conditions were investigated by using this PTV method. Based on the results of experiment, the generation process of swirl and tumble flow in a cylinder during intake stroke was clarified. Its effect on the tumble ratio at the end of compression stroke was also investigated.