• Journal of the Korean Society of Radiology
• /
• v.14 no.5
• /
• pp.705-713
• /
• 2020

Arteriosclerosis is a disease in which blood circulation is impaired due to loss of elasticity as blood vessels become narrower, and is a potential cause of recently increasing cardiovascular and cerebrovascular diseases. Carotid ultrasound is used as a predictor of cardiovascular and cerebrovascular diseases by evaluating the degree of atherosclerosis. Therefore, this paper attempted to investigate the correlation between the increase in the thickness of the inner media and various clinical variables in carotid ultrasound. Patients with carotid ultrasound findings were classified into three stages: mild intima thickening, sclerosis, and significant stenosis. CAVI (Carotid Ankle Vascular Index: vascular age) data measured in the degree and physical characteristics of the carotid artery(gender, age, body mass index, blood pressure), blood test(total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, creatine phosphokinase, fasting blood sugar), and arteriosclerosis test were collected. It was confirmed that the carotid intima thickness was correlated with variables such as hypertension, hyperlipidemia, and BMI, and also correlated with the risk factors of cardiovascular disease as CAVI increased.

• Journal of Welding and Joining
• /
• v.26 no.4
• /
• pp.85-91
• /
• 2008

The grooving corrosion is caused mainly by the different microstructures between the matrix and weld which is formed during the rapid heating and cooling cycle in welding. By this localized corrosion reaction of pipes, it evolves economic problems such as the early damage of industrial facilities and pipe lines of apartment, and water pollution. So lots of researches were carried out already about grooving corrosion mechanism of ERW carbon steel pipe but there is seldom study for water hammer happened by fluid phenomenon and corrosion rate by flow velocity. In this study, the analysis based on hydrodynamic and fracture mechanics was carried out. ANSYS, FLUENT and STAR-CD were used for confirmation of flow phenomenon and stress on the pipe. As the results, fatigue failure is able to be happened by water hammer and grooving corrosion rate is increased cause by turbulent. Grooving corrosion is happened on the pipe, then friction loss of fluid is occurred from corroded part. Erosion can be happened enough in corroded region of microscopic size that wear "V" form. Also pipe is able to be damaged by water hammer effects because of corroded region is general acting as a notch effects. Corrosion depth was more than half of total thickness, it can be damaged from water hammer pressure.

• Korean journal of food and cookery science
• /
• v.31 no.5
• /
• pp.642-651
• /
• 2015

Asparagus, which was known to be a good source of dietary fiber and vitamins, has been reported to possess various medical actions such as antioxidant and blood pressure regulating effects. In order to examine the quality and antioxidant characteristics of asparagus, asparagus sponge cakes were prepared with different ratios of freeze dried asparagus powder (0%, 2%, 4%, 6%, 8%, w/w) in this study. With the increase of asparagus powder content in the sponge cakes, the specific gravity and baking loss increased while the dough yield decreased significantly. The moisture contents of the sponge cakes were not significantly different between the control and the cakes prepared with asparagus powder. The pH of the sponge cakes decreased significantly with increased amounts of asparagus powder. Furthermore, the pH of the sponge cake containing 8% asparagus powder was the lowest at 7.49. With the increase of asparagus powder content in the sponge cakes, lightness (L) and redness (a) decreased, whereas yellowness (b) increased. In texture analysis, the hardness and chewiness of the sponge cakes increased as the asparagus powder content increased, while the cohesiveness of the sponge cakes with asparagus powder decreased. Both total polyphenol content and DPPH (1,1-diphenyl-2-picryl hydrazyl) radical scavenging activity increased significantly with increased levels of asparagus powder content in the sponge cakes. In a sensory evaluation using a scale of 1-7, the sponge cake containing 8% asparagus powder had the lowest sensory preference scores. Therefore, the results of this study suggest that sponge cake prepared with 6% asparagus powder is the most appropriate product for quality characteristics.

• Nuclear Engineering and Technology
• /
• v.36 no.1
• /
• pp.24-35
• /
• 2004

In order to analyze the hydrogen distribution during a severe accident in the APR1400 containment, GASFLOW II was used. For the APR1400 NPP, a hydrogen mitigation system is considered from the design stage, but a fully time-dependent, three-dimensional analysis has not been performed yet. In this study GASFLOW code II is used for the three-dimensional analysis. The first step to analysis involving hydrogen behavior in a full containment with the GASLOW code is to generate a realistic geometry model, which includes nodalization and modeling of the internal structures such as walls, ceilings and equipment. Geometry modeling of the APR1400 is conducted using GUI program by overlapping the containment cut drawings in a graphical file format on the mesh view. The total number of mesh cells generated is 49,476. And the calculated free volume of the APR1400 containment by GASFLOW is almost the same as the value from the GOTHIC modeling. A hypothetical SB-LOCA scenario beyond design base accident was selected to analyze the hydrogen behavior with the hydrogen mitigation system. The source of hydrogen and steam for the GASFLOW II analysis is obtained from a MAAP calculation. Combustion pressure and temperature load possibilities within the compartments used in the GOTHIC analysis are studied based on the Sigma-Lambda criteria. Finally the effectiveness of HMS installed in the APR1400 containment is evaluated from the point of severe accident management

• Korean Journal of Materials Research
• /
• v.12 no.7
• /
• pp.573-579
• /
• 2002

Stoichiometric mullite ($3Al_2$$O_3$. $2SiO_2$) precursor sol has been prepared by sol-gel method. The effects of the precursor pH and sintering temperature on the synthesizing behavior and morphology of mullite have been studied. Mullite precursor sol was prepared by dissolution of aluminum nitrate enneahydrate (Al($NO_3$)$_3$.9H$_2O) into the mixture of silica sol. Precursor pH of the sols was controlled to acidic condition ($PH\leq$ 1~1.5) and to basic condition ($pH\geq$8.5~9). The synthesized aluminosilicate sols were formed under 20 MPa pressure after drying at $150^{\circ}C$ for 24 hours, and then sintered for 3hours in the temperature range of $1100~1600^{\circ}C$. From TGA/DTA analysis, total weight loss in the aluminosilicate gel of the acidic sample was (equation omitted) 56% and that of the basic sample was (equation omitted) 85%, indicating that the synthesizing temperature of mullite phase for acidic and basic samples was above $1200^{\circ}C$ and $1300^{\circ}C$, respectively. The morphologies of the synthesized mullite were fine and needle-like (or rod-like) for acidic sample, and granular for basic sample that has been sintered above $1300^{\circ}C$. It was found that the morphology of mullite particle was predominantly governed by precursor pH and sintering temperature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.406-413
• /
• 2011

This paper presents the shape optimization of a nonaxisymmetric endwall and endwall boundary layer fence which improve the aerothermal environment of a gas turbine passage. The endwall and fence methods were used simultaneously. The turbine passage was simulated by a $90^{\circ}$ turning duct ($Re_D$=360,000). The main purpose of the present investigation was to focus on finding a nonaxisymmetric endwall and boundary layer fence with minimum total pressure loss in the passage and heat transfer coefficient on the endwall of the duct. An approximate optimization method was used for the investigation to secure the computational efficiency. Results indicated that a significant improvement in aerothermal environment can be achieved through the application of a nonaxisymmetric endwall and boundary layer fence.

• Journal of Family Resource Management and Policy Review
• /
• v.22 no.4
• /
• pp.17-32
• /
• 2018

The purpose of this study was to explore the effects of family life stress and family values on marital stability among middle-aged couples. The subjects included a total of 302 men and women aged 45-64 who had been married for more than 20 years and were living in Seoul. The collected data were statistically analyzed with the SPSS 21.0 Package. First, Cronbach's alpha was calculated to measure the reliability of the scale that assessed the variables of the research model. Then, mean and standard deviation were calculated to determine the degrees of family life stress, family values, and marital stability among the subjects. Finally, a hierarchical multiple regression analysis was performed to identify factors that affected the subjects' marital stability. The results revealed that the level of family life stress in middle-aged married men and women was slightly higher than the mean value. Of all the sub-scales of family life stress, the subjects were found to experience the most stress from factors related to financial pressure, followed by family relationships, a sense of loss within a family, and work-family compatibility. Therefore, financial problems were one of the critical stressors for middle-aged married couples. Also, for this demographic, the levels of family values and marital stability were higher than the medians. The factors affecting marital stability in middle-aged couples were identified to be family relationship stress, financial stress, subjective economic status, family values, stress related to work-familycompatibility,religion,andage.Thedegreeofmaritalstabilitywashigherinmiddle-agedcouplesa stheirstresslevelsfromfamilyrelationshipsandfinancialproblemswerelower.Moreover,thehigherthes ubjectiveeconomicstatusandthemoretraditionalthefamilyvalues,thehigherthedegreeofmaritalstabili ty.Finally,marriedcoupleswhowerereligioushadalowerlevelofstressfromwork-family compatibility, and the younger the couples, the higher the degree of marital stability.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.25 no.2
• /
• pp.1-11
• /
• 2021

The cavity inside the combustor increases the mixing efficiency of fuel and air by inducing a oscillation of the flow and the recirculation area with a low speed, and enables continuous combustion by maintaining the flame. In this study, the characteristics of the internal flow by change in the shape parameters of the cavity were analyzed through experiments and two-dimensional computational analysis. It was observed that the flow in the supersonic combustor was greatly influenced by various shape parameters of cavity besides L/D. Even with the same L/D, it was confirmed that the flow type varies depending on the depth of the cavity, either open or closed type, and the aft ramp angle of the cavity and the height of the combustor also affect the flow characteristics. As a result, the change in the shape parameters of the cavity had a great influence on the total pressure loss.

• Korean Journal of Food Science and Technology
• /
• v.21 no.6
• /
• pp.788-794
• /
• 1989

This study was attempted to investigate the effects of blanching temperature and cooking methods on the changes in the proportions of vitamin C of fresh potato and potatoes with different storage time. Sensory evaluation of fresh potato by different cooking methods was also conducted. The contents of residual ascorbic acid(AA) and total ascorbic acid(TAA) of fresh potato were maximum at $40^{\circ}C$ followed by rapid decrease at $50-65^{\circ}C$ while leached AA and TAA showed steady increase as the blanching temperature increased. Oxidized AA and dehydroascorbic acid(DHA) hydrolyzed increased at $50-65^{\circ}C$. From these results, it was considered that AA was lost mainly by oxidation up to $65^{\circ}C$ and leaching of AA was the major mode of loss above $65^{\circ}C$. In the case of potatoes stored for 1-4 weeks, they showed similar changes in the proportions of vitamin C as that of fresh potato. However, at $40^{\circ}C$ the content of residual TAA decreased and those of leached TAA and DHA hydrolyzed increased redundant during storage. At $65^{\circ}C$, the content of DHA hydrolyzed decreased The residual TAA of fresh potato by different cooking methods decreased in the order of pressure cooking (PC) > microwave cooking (MC)>boiling. Leached TAA were 49.5% and 36.4%, during boiling and MC, respectively. While DHA hydrolyzed were 22.3% and 4.2%, respectively Leached TAA and DHA hydrolyzed during PC were not determined. From these results, it was considered that AA was lost mainly by leaching during cooking. Residual TAA of stored potatoes by different cooking methods decreased during storage. But leached TAA and DHA hydrolyzed did not show any steady increase or decrease. Overall eating quality of fresh potato by different cooking methods decreased in the order of PC>MC>boiling(p<0.05).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.5
• /
• pp.346-353
• /
• 2016

In the design conditions of some research reactors, the siphon phenomenon can cause continuous efflux of water during pipe rupture. A siphon breaker is a safety device that can prevent water efflux effectively. However, the analysis of the siphon breaking is complicated because many variables must be included in the calculation process. For this reason, a simulation program was developed with a user-friendly GUI to analyze the siphon breaking easily. The program was developed by MFC programming using Visual Studio 2012 in Windows 8. After saving the input parameters from a user, the program proceeds with three steps of calculation using fluid mechanics formulas. Bernoulli's equation is used to calculate the velocity, quantity, water level, undershooting, pressure, loss coefficient, and factors related to the two-phase flow. The Chisholm model is used to predict the results from a real-scale experiment. The simulation results are shown in a graph, through which a user can examine the total breaking situation. It is also possible to save all of the resulting data. The program allows a user to easily confirm the status of the siphon breaking and would be helpful in the design of siphon breakers.