• Advances in Energy Research
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• v.1 no.2
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• pp.147-163
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• 2013

The world faces several issues of energy crisis and environmental deterioration due to over-dependence on single source of which is fossil fuel. Though, fuel is needed as ingredients for industrial development and growth of any country, however the fossil fuel which is a major source of energy for this purpose has always been terrifying thus the need for alternative and renewable energy sources. The search for alternative energy sources resulted into the acceptance of a biofuel as a reliable alternative energy source. This work presents the study of optimization of process of transesterification of vegetable oil to biodiesel using NaOH as catalyst. A $2^4$ factorial design method was employed to investigate the influence of ratio of oil to methanol, temperature, NaOH concentration, and transesterification time on the yield of biodiesel from vegetable oil. Low and high levels of the key factors considered were 4:1 and 6:1 mole ratio, 30 and $60^{\circ}C$ temperatures, 0.5 and 1.0 wt% catalyst concentration, and 30 and 60 min reaction time. Results obtained revealed that oil to methanol molar ratio of 6:1, tranesetrification temperature of $60^{\circ}C$, catalyst concentration of 1.0wt % and reaction time of 30 min are the best operating conditions for the optimum yield of biofuel from vegetable oil, with optimum yield of 95.8%. Results obtained on the characterizzation of the produced biodiesel indicate that the specific gravity, cloud point, flash point, sulphur content, viscosity, diesel index, centane number, acid value, free glycerine, total glycerine and total recovery are 0.8899, 4, 13, 0.0087%, 4.83, 25, 54.6. 0.228mgKOH/g, 0.018, 0.23% and 96% respectively. Results also indicate that the qualities of the biodiesel tested for are in conformity with the set standard. A model equation was developed based on the results obtained using a statistical tool. Analysis of variance (ANOVA) of data shows that mole ratio of ground nut oil to methanol and transesterification time have the most pronounced effect on the biodiesel yield with contributions of 55.06% and 9.22% respectively. It can be inferred from the results various conducted that vegetable oil locally produced from groundnut oil can be utilized as a feedstock for biodiesel production.

• Korean Journal of Community Nutrition
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• v.18 no.1
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• pp.77-87
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• 2013

This study was conducted to investigate the nutrient intakes of subjects by quartile of percent energy intake from cooked rice, consumption of cooked rice mixed with multi-grains and to evaluate rice consumption in relation to the risk of metabolic syndrome. The subjects were 5,830 males and females aged between 20~64 years based on 2007-2008 KNHNES data. Levels of percent energy intake from cooked rice were classified into 4 groups (Q1, Q2, Q3, Q4 groups: 25% of each) using data of 24-hour recall method from KNHNES. Using medical examination and questionnaire, subjects were classified according to diagnostic criteria of metabolic syndrome. The subjects with higher age, being married, lower education, lower economic level were more likely to take higher percent energy intake from cooked rice. Quartile Q3 of percent energy intake from cooked rice tended to show higher Index of Nutritional Quality (INQ) for fiber, calcium, iron, potassium and vitamin A. INQ of protein, dietary fiber, calcium, thiamin, phosphorus, potassium, riboflavin, niacin and vitamin C by consumption of cooked rice mixed with multi-grains was higher than that by consumption of cooked white rice when adjusted for age. No association with a risk for metabolic syndrome was found for quartile of percent energy intake from cooked rice or cooked rice mixed with multi-grains compared to cooked white rice after adjusting for energy, gender, age, BMI, alcohol, smoking, income and physical activity. In conclusion, consumption of over 54% energy intake from cooked rice or only cooked white rice showed relatively low INQs, but was not associated with a higher risk for metabolic syndrome.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.17-29
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• 2020

Purpose: The purpose of this work was to investigate the dosimetric impact of mixed energy partial arc technique on prostate cancer VMAT. Materials and Methods: This study involved prostate only patients planned with 70Gy in 30 fractions to the planning target volume (PTV). Femoral heads, Bladder and Rectum were considered as oragan at risk (OARs). For this study, mixed energy partial arcs (MEPA) were generated with gantry angle set to 180°~230°, 310°~50° for 6MV arc and 130°~50°, 310°~230° for 15MV arc. Each arc set the avoidance sector which is gantry angle 230°~310°, 50°~130° at first arc and 50°~310° at second arc. After that, two plans were summed and were analyzed the dosimetry parameter of each structure such as Maximum dose, Mean dose, D2%, Homogeneity index (HI) and Conformity Index (CI) for PTV and Maximum dose, Mean dose, V70Gy, V50Gy, V30Gy, and V20Gy for OARs and Monitor Unit (MU) with 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC plan. Results: In MEPA, the maximum dose, mean dose and D2% were lower than 6MV 1 ARC plan(p<0.0005). However, the average difference of maximum dose was 0.24%, 0.39%, 0.60% (p<0.450, 0.321, 0.139) higher than 6MV, 10MV, 15MV 2 ARC plan, respectively and D2% was 0.42%, 0.49%, 0.59% (p<0.073, 0.087, 0.033) higher than compared plans. The average difference of mean dose was 0.09% lower than 10MV 2 ARC plan, but it is 0.27%, 0.12% (p<0.184, 0.521) higher than 6MV 2 ARC, 15MV 2 ARC plan, respectively. HI was 0.064±0.006 which is the lowest value (p<0.005, 0.357, 0.273, 0.801) among the all plans. For CI, there was no significant differences which were 1.12±0.038 in MEPA, 1.12±0.036, 1.11±0.024, 1.11±0.030, 1.12±0.027 in 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC, respectively. MEPA produced significantly lower rectum dose. Especially, V70Gy, V50Gy, V30Gy, V20Gy were 3.40, 16.79, 37.86, 48.09 that were lower than other plans. For bladder dose, V30Gy, V20Gy were lower than other plans. However, the mean dose of both femoral head were 9.69±2.93, 9.88±2.5 which were 2.8Gy~3.28Gy higher than other plans. The mean MU of MEPA were 19.53% lower than 6MV 1 ARC, 5.7% lower than 10MV 2 ARC respectively. Conclusion: This study for prostate radiotherapy demonstrated that a choice of MEPA VMAT has the potential to minimize doses to OARs and improve homogeneity to PTV at the expense of a moderate increase in maximum and mean dose to the femoral heads.

• Journal of Nutrition and Health
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• v.35 no.3
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• pp.303-313
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• 2002

The purpose of this study was to compare the anthropometry, blood pressure, blood lipid levels, and nutrient intakes in three groups: a group with an impaired fasting blood glucose (IFG) condition (62 males and 30 females); a group with normal blood glucose (73 males and 50 females); and a group with diabetes mellitus (DM) (79 males and 49 females). In male subjects, body mass index (BMI) and obesity index values were significantly higher in the IFG group than in normal and DM groups, but waist/hip ratio (WHR), systolic blood pressure, and diastolic blood pressure were not significantly different from those of the DM group. In female subjects, there was no difference in body weight, BMI, obesity index and WHR values between the IFG and the DM groups. The prevalence of obesity in the IFG group (males 43.6%, females 76.7%) was the highest among the three groups. The percentage of high SBP (40.0%) and high DBP (52.0%) in male subjects of the IFG group was significantly greater than in the DM group or the normal group. In the male subjects, the serum triglyceride concentration was significantly higher in the DM group than in the normal and IFG groups. There was no difference in various nutrient intakes(energy, carbohydrate, protein, fat, calcium, iron, vitamin A and cholesterol) among the three groups. In male subjects, the percentage of energy intake from alcohol was higher in the IFG group (7.0%) than that of the normal (4.5%) and the DM (5.6%) groups. The fasting blood glucose level had a positive correlation with WHR, TG, the athrogenic index and LDL-cholesterol/HDL-cholesterol. This study suggested that the IFG group had a higher obesity index, BMI, blood pressure and serum lipid levels (TG, cholesterol) than the normal or the DM group; furthermore, the IFG group had higher levels of alcohol intake and habits of taking unbalanced diets. Therefore, guidelines for IFG group should emphasize weight control, diet therapy, physical activities and regular balanced diets, in order to prevent diabetes in this group.

• Journal of Korean Home Economics Education Association
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• v.18 no.4 s.42
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• pp.67-84
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• 2006

This study was carried out to investigate nutrient intake, dietary self-efficacy, and physical activity self-efficacy of elementary school students by obesity index in Gyeongbuk area. The survey was conducted from June 7 to June 18 in 2005. The study was peformed by analyzing a questionnaire answered by 523 elementary school student in 5th and 6th grade. The obesity index was gained by height and weight data. Nutrient intakes was evaluated by 24hr-dietary record. Statistical data analysis were completed using the SPSS 12.0 program. The results were summarized as follows; The result of the body measurement was that 31.7% of underweight group, 45.1% of normal group, 12.8% of overweight group, 10.3% of obese group. 13.9% of underweight group experienced weight control, and 17.5% of the subject respond they will try the weight control in the future. Male students showed significantly higher exercise frequency than female students(p<0.001). Male underweight group and female obese group show the highest exercise frequency. Daily energy intake of the subject showed 80.1% in male students and 87.5% in female students revealed under the recommended dietary allowance(RDA) for Korean. The intake ratio of energy nutrients was identical in male and female of underweight group and obese group, so this showed that intake style was similar in two groups. By investigating through MAR(mean adequacy ratio), underweight group of male students and both normal and overweight group of female students were lowest, while overweight group of male students and underweight group of female students were the highest. Physical activity self-efficacy of male students was higher than female students, and physical activity self-efficacy by obesity index was higher in underweight group of male students and obese group in female.

• Journal of Nutrition and Health
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• v.45 no.2
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• pp.127-139
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• 2012

This study was conducted to evaluate the effects of an abdominal obesity management program on dietary intake, stress index, and waist to hip ratio (WHR) in abdominally obese women. The subjects were 195 adult abdominally obese women (WHR ${\geq}$ 0.80) who had been participating in a nutrition education (total of nine times) and dietary habits and life style modification programs (total of six times) for 12 weeks. The abdominal obesity management program focused on the nutrition provided by breakfast, lunch, and dinner, proper dietary habits, and practices to improve life style. The subjects were divided into a WHR decrease group and a WHR increase group according to changes in the WHR. Daily nutrient intake was assessed with a 3-day food record, body measurements and blood vessel age, stress index, and a health index that were measured at baseline and after 12 weeks. After the intervention, weight, waist circumference, hip circumference, WHR, and body mass index (BMI) decreased significantly in the WHR decrease group. Energy intake increased from 1486.2 kcal to 1541.4 kcal with a significant improvement in nutrient density for animal protein, total fat, animal fat, fiber, calcium, phosphorus, zinc, vitamin $B_6$, vitamin C, vitamin E, and saturated fatty acids in the WHR decrease group. Additionally, dietary diversity increased significantly in the WHR decrease group compared to that in the WHR increase group. The WHR decrease group showed a significant improvement in the stress and health indices. Changes in WHR were correlated with changes in nutrient intake (animal protein, total fat, animal fat, plant fat, fiber, calcium, iron, potassium, vitamin A, vitamin $B_2$, vitamin $B_6$, vitamin C, and folate) and medical index profiles (stress and indices) adjusted for age, birth status, baseline BMI, and baseline WHR. These results show that an abdominal obesity management program was effective not only for reducing the WHR but also to improve dietary intake and the stress index in abdominally obese women.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.387-392
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• 2017

A high-performing all-transparent photodetector was created by configuring a $MoO_x$/NiO/ZnO/ITO structure on a glass substrate. The ITO bottom layer was applied as a back contact. To achieve the transparent p/n junction, p-type NiO was coated on the n-type ZnO layer. Reactive sputtering was used to spontaneously form the ZnO or NiO layer. In order to improve the transparent photodetector performance, the functional $MoO_x$ window layer was used. Optically, the $MoO_x$ window provided a refractive index layer (n=1.39) lower than that of NiO (n=2), increasing the absorption of the incident light wavelengths (${\lambda}s$). Moreover, the $MoO_x$ window can provide a lower sheet resistance to improve the carrier collection for the photoresponses. The $MoO_x$/NiO/ZnO/ITO device showed significantly better photoresponses of 877.05 (at ${\lambda}$=460nm), 87.30 (${\lambda}$=520 nm), and 30.38 (${\lambda}$=620 nm), compared to 197.28 (${\lambda}$=460 nm), 51.74 (${\lambda}$=520 nm) and 25.30 (${\lambda}$=620 nm) of the NiO/ZnO/ITO device. We demonstrated the high-performing transparent photodetector by using the multifunctional $MoO_x$ window layer.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.9
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• pp.431-437
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• 2002

Low hemolysis is one of the key factors in the production of successful rotary blood pumps. It is, however, difficult to identify the areas where hemolysis occurs. Computational fluid dynamics(CFD) analysis enables the engineer to predict hemolysis on a computer Fluid dynamics in five different axial flow pumps was analyzed 3-dimensionally using CFD software. The impeller was rotated at a speed which supplied a flow of 5L/min at a pressure difference of 100mmHg. Changes in the turbulent kinetic energy along streamlines through the pumps were computed. Reynolds' shear stress( (equation omitted) ) was calculated using the turbulent kinetic energy. Hemolysis was evaluated based on Reynolds'shear stress and its exposure time(t) : dHb/Hb=3.62$\times$10$^{-5}$ $t^{0.785}$$\tau$$^{2.416}$ . Hemolysis of the pumps was measured in vitro using fresh bovine blood to which citrate phosphate dextrose was added to prevent clotting. A pump flow of 5L/min was maintained at a pressure difference of 100mmHg for 3h. The normalized index of hemolysis(NIH) as measured. Reynolds' shear stress was high behind the impellers. The measured NIH and the calculated hemolysis(dHb/Hb) shoed a good correlation; NIH=0.0003(dHb/Hb) (r=0.90, n=6) in the range of NIH between 0.003 and 1.1. CFD analysis can predict the in vitro results of hemolysis as well as the areas where hemolysis occurs.ysis occurs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.303-310
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• 2000

Fracture toughness of five different reactor pressure vessel steels was characterized in the transition temperature region by the ASTM E1921-97 standard method using Charpy-sized small specimens. T he predominant fracture mode of the tested steels was transgranular cleavage in the test conditions. A statistical analysis based on the Weibull distribution was applied to the interpretation of the scattered fracture toughness data. The size-dependence of the measured fracture toughness values was also well predicted by means of the Weibull probabilistic analysis. The measured fracture toughness transition curves followed the temperature-dependence of the ASTM master curve within the expected scatter bands. Therefore, the fracture toughness characteristics in the transition region could be described by a single parameter, so-called the reference temperature (T。), for a given steel. The determined reference temperatures of the tested materials could not be correlated with the conventional index temperatures from Charpy impact tests.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.208-213
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• 2013

In this study, the effect of phosphorus flame retardants on the flame retardancy of the flexible polyurethane foam (PUF) was investigated. Tetramethylene bis(orthophosphorylurea) [TBPU] and phosphinyl alkylphosphate ester [CR-530], resorcinol bis diphenylphosphate [RDP], triethyl phosphate [TEP] were used as flame retardants. The results of thermogravimetric analysis (TGA) indicate that TBPU added PUF produces more charred residues than the other flame retardant added PUF. It was found that TBPU added PUF exhibits low mean heat release rate (HRR), peak HRR, effective heat of combusion (EHC), mass loss rate (MLR), CO yield and $CO_2$ compared to those other flame retardants.