• Journal of Bio-Environment Control
• /
• v.31 no.3
• /
• pp.143-151
• /
• 2022

This study was carried out to investigate quantitative characteristics of the cooling effect in a single-span arch greenhouse with roll-up side vents depending on operation of circulation and exhaust fans during ventilation, in order to suggest a practical strategy regarding installation or operation of forced ventilation systems. The examination was conducted under 3 different ventilation conditions (side vents only, side vents + circulation fans, and side vents + circulation fans + exhaust fans). In each condition, variations of internal and external air temperatures and exogenous environmental factors were recorded during ventilation, and the cooling effects were investigated by comparing the normalized temperature difference (NTD) of each ventilation condition. In the morning time (11:00-12:00), a temporary peak in the temperature difference was observed at the beginning of ventilation regardless of ventilation methods. The time taken to the maximum NTD was decreased from 340 s to 110s, and the NTD was dropped from 1.158 to 1.037 as the more forced ventilation systems were operated. The more operations caused the passing time over specific NTD values reduced by 60% as the time was reduced from 1,030 s to 550 s at NTD = 0.8, 1,610 s to 915 s at NTD = 0.6, and 2,315 s to 1,360 s at NTD = 0.4. The temporary peak in NTD was not observed in the afternoon time (14:00-15:00) but it was dropped as quickly as the ventilation started. Also the more operations resulted in the passing time over specific NTD values reduced by 70% as the time was reduced from 560 s to 345 s at NTD = 0.8, from 825 s to 540 s at NTD = 0.6, and from 1,145 s to 810 s at NTD = 0.4. Conclusively, the intervention of the forced ventilation system is recommended in the morning time or in high thermal conditions to achieve more effective and economical ventilation.

• Korean Journal of Poultry Science
• /
• v.29 no.3
• /
• pp.195-204
• /
• 2002

Two experiments were conducted to study the effects of nutrient level and feeding method of split diets for a.m. and p.m. on laying hen performance, feed cost and eggshell quality. In experiment 1, 384 ISA Brown layers of 30∼38wk of age were assigned to four treatments which comprise of three replicates each containing 32 birds. The control(C) was fed a conventional single diet throughout the day and split diet groups(T1, T2 and T3) were offered high energy/protein-low Ca diets, and low energy/protein-high Ca diets in a.m.(04:00∼15:00) and p.m.(15:00∼21:00), respectively. In the split diet groups, daily ME and CP consumption, and feed cost were significantly reduced(P<0.05) compared to the C, while the hen-day egg production, average egg weight and daily feed intake were not different among treatments. Due to the reduced daily ME and CP intakes and feed cost, the conversions of feed, ME, CP and feed cost required per day and per kg egg mass were also significantly improved(P<0.05) in the split diet groups. Eggshell qualities (egg specific gravity, egg breaking strength and eggshell thickness) were improved(P<0.05) by split diet feeding. As the Ca level of the p.m. diet increased. In Experiment 2, 384 ISA Brown layers of 50∼58 wk of age were used in three treatments and each treatment was represented by four replicates each containing 32 birds. The control(C) was fed a conventional single diet throughout the day and split diet group(T1) was offered high energy/protein-low Ca diets, and low energy/protein-high Ca diets in a.m.(04:00∼l5:00) and p.m.(15:00∼21:00), respectively. T2 group was fed the diet mixed (50:50) with the a.m. diets in mash and p.m. diet in pellet used T1 group. In T1 and T2 groups, daily feed intake and average egg weight were significantly reduced(P<0.05) compared to the C, while the hen-day egg production was not influenced by the feeding system. Daily ME and CP consumption, and feed cost were reduced(p.0.05), and the conversions of ME, CP and feed cost required per egg were also significantly improved(P<0.05) in T1 and T2, while the conversions of feed, ME, CP and feed cost required per kg egg mass were not different to the C. Eggshell qualities of T1 and T2 were improved(P<0.05) compared to the others. It was concluded the feed and nutrients consumption, feed cost per day or per kg egg mass could be reduced by introducing split diets for a.m. and p.m. and the feeding method of mixed diet of split diets were also convenient and effective for sparing feed cost and improvement of eggshell quality.

• Archives of design research
• /
• v.18 no.4 s.62
• /
• pp.105-118
• /
• 2005

Housing environment for human beings has been diversified and more convenient due to the development of high technology and civilization brought by industrialization in the 20th century. In the 21st century, how to overcome the ecological limit of biased development-centered advancement, that is, how to preserve and hand over a clean and healthy 'sustainable environment' to our next generations has been one of the most-talked about issues. Environmental symbiosis means a wider range of environmental harmony from micro-dimensional perspective to macro one. The three goals of a environmentally friendly house are to preserve global environment, to harmonize with the environment around, and to offer a healthy and comfortable living environment. From the point of view of environmental symbiosis, houses should be designed to save energy and natural resources for preservation of global environment, to collect such natural energy resources as solar heat and wind force, to recycle waste water, and recycle and reduce the amount of the waste matter. Now, the environmentally-friendly house became a new social mission that is difficult to not only challenge but also realize without conversion to a new paradigm, ecologism.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.2
• /
• pp.331-338
• /
• 2004

Folate nutrition in early pregnancy is crucial in order to prevent neural tube defects (NTDs) in the fetus and maternal folate deficiency in late pregnancy If the influencing factors on maternal folate status are identified we may be able to detect the women at most risk of folate deficiency. This study intends to determine folate intakes, assess the levels of serum folate, erythrocyte folate, and plasma homocysteine, and reveal theinfluencing factors on maternal folate status in early pregnancy. A total of 151 healthy women in their first trimester volunteered for this study. The average length of gestation period was 9.1$\pm$ 2.3 weeks and seventy subjects were primipara. They consumed 1599$\pm$589 ㎉/day of energy and 230.8$\pm$145.2 $\mu\textrm{g}$/day of folate. This represented 72.5％ and 46.2％ of the Korean RDA respectively for pregnant women in the first half of Pregnancy. Results show that they consume less folate and energy due to morning sickness. Morning sickness correlated negatively with the intakes of energy, folate, ana Kimchi also. Their levels of serum folate, erythrocyte folate, and plasma homocysteine were 5.5$\pm$1.9 ng/mL, 266.6$\pm$75.0 ng/mL, and 7.0$\pm$1.8 $\mu$mol/L, respectively. Results indicate that 7.8% were deficient and 60.3% were borderline deficient in serum folate, 4.3% were deficient in erythrocyte folate, however, all had normal levels of plasma homocysteine. Results indicate that the folate status was not poor Contributing factors influencing serum folate concentrations ($R^2$= 0.724, p = 0.0001) were self-reported health status (+), folate intake (+), age (-), length of gestation (-), and homocysteine levels (-). Factors influencing erythrocyte folate concentrations ($R^2$ = 0.570, p = 0.0029) were the infant birth height of the last pregnancy (+), energy intake (+), age (-), plasma homocysteine concentration (-), and education level (-). Factors influencing plasma homocysteine concentrations ($R^2$= 0.450, p = 0.0051) were income level (+), prepregnancy weight (+), serum folate concentration (-), and the infant birth weight of the last pregnancy (-). These results indicate that pregnant women are likely to have a folate deficiency if they are in poor health status, having a history of delivering small infant and low energy and/or folate intake, and/or are older. And folate status is likely to decline as pregnancy progresses.

• Korean Journal of Food Science and Technology
• /
• v.14 no.3
• /
• pp.197-202
• /
• 1982

Kinetic study for the thermal degradation of ginsenosides in ginseng extract was conducted. The results indicate that the thermal degradation followed first order kinetics and rate constants varied substantially depending on the types of ginsenosides and heat treatment temperatures. Activation energy calculated by Arrhenius plots ranged from 16.80 kcal/mole to 30.10 kcal/mole and $Q_{10}$ values ranged from 2.01 to 3.49. Correlation coefficients between the change of ginsenoside contents by thermal degradation and heat treatment temperature were $0.995{\sim}0.999$. The dependence on temperatures of the decomposition rate constant of total ginsenoside can be expressed as $k=4.574{\times}10^8$ exp(8898.8/T).

• Journal of radiological science and technology
• /
• v.31 no.1
• /
• pp.25-31
• /
• 2008

Purpose : This study was conducted to understand for the diagnostic discordance of bone mineral density(BMD) in DEXA(Dual Energy X-ray Absorptiometry). And the diagnostic difference between lumbar spine and femur neck, forearm was evaluated using T-score. Materials and Methods : We studied 220 females measured BMD on lumbar spine, and femur neck, forearm including ward's triangle and ultra digital(UD). We were distinguished T-score into normal, osteopenia, osteoporosis(WHO classification) and evaluated discordance rate according to age and degree of bone loss. Correlation analysis and chi-square test between L-spine, L-4, femur neck, Ward, Forearm, UD were carried out. Results : In the lumbar spine, the number of normal were in 57(25.9%), osteopenia in 86(39.1%), osteoporosis in 77(35.0%). In the L-4 and ward's triangle, the number of osteoporosis were in 78(35.5%), in 126(57.3%). There was significant correlation between lumbar, femur neck and forearm BMD in all cases. The discordance of BMD between lumbar and femur were 57%, lumbar and forearm 43%, forearm and femur 51%. The discordance rates of normal, osteopenic, osteoporotic groups were 39%, 64%, 43%, respectively, showing the highest discordance rate in osteopenia patients. In normal group of lumbar spine, the discordance rate was 25%, 23%, 11%, 65%, 86% in 30', 40', 50', 60', 70', respectively. In osteopenia, osteoporosis group of lumbar spine, the discordance rate was 62%, 55%, 36%, 20%, 9% in 30', 40', 50', 60', 70', respectively. Conclusion : It was different of the results of BMD with lumbar, femur and forearm site. The discordance rate was decreased with age in osteopenia, osteoporosis lumbar spine. In osteopenia group, the discordance rate was the highest. So, it is necessary that the BMD of lumbar, femur neck and forearm should be checked.

• Journal of the East Asian Society of Dietary Life
• /
• v.6 no.2
• /
• pp.167-176
• /
• 1996

This nutritional survey was conducted from July to August 1993, in order to investigate the nutrition knowledge, food habits, nutrient intake, and their correlation of high school girl students living in large city, middle and small city, and rural area. The subjects of this survey were 164 students living in large city, Seoul and Pusan, 289 students living in noddle and small city, Chonju and Iksan-City, and 252 students living in rural area, Samnye-Up and Kimje-Kun, Chonbuk-Province. The results obtained are summarized as follows: The perceived nutrition knowledge of large city, middle and small city, and rural area was 80.1%, 83.9%, and 76.0%, respectively, and their accuracy was 62.0%, 64.2%, 56.3% respectively The nutritional knowledge score of large city, middle and small city, and rural area was 14.90, 16.16, 12.84, respectively. The nutrition knowledge score was significant among large city, middle and small city, and rural area. The correlation coefficient between nutrition knowledge and food habits was significant among large city, and middle and small city students. The food habits score of rural area subjects were lowest. The correlation between food habit and calcium, vitamin 4 and vitamin C were significant among large city girls. In rural students the correlation between food habits and protein, phosphorus, iron, vitamin B1, vitamin B2, and vitamin C was significant.

• Journal of Nutrition and Health
• /
• v.41 no.1
• /
• pp.41-53
• /
• 2008

Gestational diabetes mellitus (GDM) is defined as glucose intolerance discovered or onset during pregnancy and attention is needed because of increased risk of perinatal morbidties and higher incidence of diabetes afterward. This study was performed to identify dietary factors associated with the development of gestational diabetes mellitus (GDM). Developed food frequency questionnaire containing 192 food items were used to assess nutritional status of 246 control subjects and 104 GDM subjects. Food habits of subjects were examined in the questionnaire. The more irregularity and less variety of meal were found in GDM group compared to control group and GDM group tended to eat rapidly and do not like vegetables and greasy foods. Total score of food habits in GDM was lower than control group, which suggests that GDM group have undesirable food habits. Mean daily energy and carbohydrate intakes of GDM group were higher than those of control group, and percent energy from protein was significantly higher in control. Nutrient density of protein, calcium, phosphorus and vitamin BI of GDM group was significantly lower than those of control group. Therefore dietary quality of GDM group was lower than that of control group. Odds ratio for GDM was high when energy and carbohydrate intakes were high. And when the intakes of rice, noodle, shiruduk, hamburger, boiled egg, steamed pork shank were high, the odds ratio for GDM was high. These results indicate that the amount and frequencies of several foods and dish items were related with the occurrence of GDM subjects. On the whole, GDM subjects consumed more cereals and less vegetables and less legumes. From these results, pregnant women with GDM tended to have unhealthy food habits, and carbohydrate intake was important dietary factors on the onset of GDM.

• Korean Journal of Remote Sensing
• /
• v.36 no.5_1
• /
• pp.679-692
• /
• 2020

We coupled a CFD model to the WRF-Chem model (WRF-CFD model) and investigated the characteristics of flows and carbon monoxide (CO) distributions in a building-congested district. We validated the simulated results against the measured wind speeds, wind directions, and CO concentrations. The WRF-Chem model simulated the winds from southwesterly to southeasterly, overestimating the measured wind speeds. The statistical validation showed that the WRF-CFD model simulated the measured wind speeds more realistically than the WRF-Chem model. The WRF-Chem model significantly underestimated the measured CO concentrations, and the WRF-CFD model improved the CO concentration prediction. Based on the statistical validation results, the WRF-CFD model improved the performance in predicting the CO concentrations by taking complicatedly distributed buildings and mobiles sources of CO into account. At 04 KST on May 22, there was a downdraft around the AQMS, and airflow with a relatively low CO concentration was advected from the upper layer. Resultantly, the CO concentration was lower at the AQMS than the surrounding area. At 15 KST on May 22, there was an updraft around the AQMS. This resulted in a slightly higher CO concentration than the surroundings. The WRF-CFD model transported CO emitted from the mobile sources to the AQMS measurement altitude, well reproducing the measured CO concentration. At 18 KST on May 22, the WRF-CFD model simulated high CO concentrations because of high CO emission, broad updraft area, and an increase in turbulent diffusion cause by wind-shear increase near the ground.

• Korean journal of food and cookery science
• /
• v.19 no.6
• /
• pp.783-793
• /
• 2003

The effects of various kinds of starch (mungbean, potato, corn and a blend of potato and com starch) on the quality characteristics of muhwakwa-pyun were studied according to the storage duration. The sweetness, pH and total acidity of muhwakwa extract were analyzed, as were the Visco/Amylograph viscosity profile and DSC thermodynamic characteristics of starches. For quality characteristics, color difference, instrumental texture characteristics and sensory characteristics were compared. The sweetness of muhwakwa extract was satisfactory but the total acidity was low for Kwa-pyun manufacture. Therefore, its pH was adjusted to 3.4 by adding 10％ citric acid with an amount of 1％ of total liquid. From the Visco/Amylograph viscosity profile and DSC thermodynamic characteristics of starches, a blend of potato and com starch was found to be easy to cook and form a gel but a little more resistant than the other starches in terms of retrogradatin. Lightness (L) and yellowness (b) of Kwa-pyun increased while its redness (a) decreased by the storage. The color became whiter and the clarity decrease regardless of the kinds of starch, which became obvious after 3 days of storage. The hardness, springiness, adhesiveness and cohesiveness tended to decrease with storage, which was weak in a blend starch. The overall acceptability of Kwa-pyun made with a blend of potato and com starch was evaluated as being the best among the samples tested. Therefore, for traditional kwa-pyun manufacture manufacture mungbean starch might be replaced with a blend of potato and corn starch which is less expensive and easily available in the market nowadays.