• Structural Engineering and Mechanics
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• v.86 no.4
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• pp.473-486
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• 2023

Nowadays, urban centers are increasingly vertical, making architects and engineers look for more efficient tools to analyze the effects of wind on tall buildings. Topology optimization can be used as an efficient tool for the design of bracing systems. Therefore, this work obtained the wind loads that act in the CAARC building, following the Brazilian standard NBR 6123/1988 and using Computational Fluid Dynamics. Four loading situations were considered, using the SIMP and BESO methods to optimize two-dimensional structures. A comparison between the SIMP and BESO methods is presented, showing the differences in the geometry of the solution found by both methods, the percentage variation in the objective function values and the dimensionless processing time. The solutions obtained through the loads obtained by the Brazilian standard are also compared with the numerical solutions obtained by CFD. The results show that the BESO method presented more rigid structures compared to the SIMP method. The bracing structures obtained with the SIMP method always present similar patterns in the distribution and quantity of bars, in contrast to the BESO method where no characteristic topology pattern was observed. It was concluded that even though the structures obtained by the BESO method presented greater stiffness, the SIMP method was less susceptible to the methodology used for the determination of wind loads. Additionally, it was evident the great potential that the combination topology optimization and computational wind engineering have in the design of bracing systems of high functional and aesthetic standards.

• International Journal of High-Rise Buildings
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• v.12 no.2
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• pp.179-193
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• 2023

It is undeniable that urban greenspace is the soul of a city. Conventional urban greenspace such as parks, community gardens, playgrounds etc. located within a city reduce the negative effects of pollution, play a major role in the survival of the urban ecosystem, and promote healthy lifestyles. Today, 55% of the world's population lives in urban areas, which is expected to increase to 68% by 2050. Projections show that urbanization and the gradual migration to urban areas combined with the fast growth of the world's population, could add another 2.5 billion people to urban areas by 2050 and almost 90% of this increase will take place in Asia(UN, 2018). As a result, many plots in the cities are and will continue to be occupied with buildings to provide residential support to the increased population. This will dangerously decrease urban greenspaces. Moreover, worldwide, food crisis, energy crisis, and social crisis is posing a great threat to the existence of mankind. Additionally, the COVID - 19 has introduced a new lifestyle where from work culture to community configuration has drastically transformed. In this scenario, residential buildings will have to serve more than just providing privacy and shelter. As urban greenspaces are being occupied by concrete residential buildings, these buildings will have to compensate for the percentage of urban green they are destroying and the issues they are imposing in the process. The goal of this thesis is to design, architecturally define and, categorize comprehensive 'sustainable Greenspace'(S.G.S) for the multi-family housing scenario. These will be different than the conventional green (veranda, rooftop green) we commonly see in residential buildings. An old, dilapidated apartment building will be the target of remodeling to fulfill the purpose of this thesis.

• Earthquakes and Structures
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• v.25 no.5
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• pp.359-367
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• 2023

High-rise structures are considered as symbols of economic power and leadership. Developing countries like India are also emerging as centers for new high-rise buildings (HRB). As the land is expensive and scarce everywhere, construction of tall buildings becomes the best solution to resolve the problem. But, as building's height increases, its stiffness reduces making it more susceptible to vibrations due to wind and earthquake forces. Several systems are available to control vibrations or deflections; however, outrigger systems are considered to be the most effective systems in improving lateral stiffness and overall stability of HRB. In this paper, a 42-storey RCC HRB is analyzed to determine the optimum position of outriggers of different materials. The linear static analysis of the building is performed with and without the provision of virtual outriggers of reinforced cement concrete (RCC) and pre-stressed concrete (PSC) at different storey levels by response spectrum method using finite element based Extended3D Analysis of building System (ETABS) software for determining responses viz. storey displacement, base shear and storey drift for individual models. The maximum allowable limit and percentage variations in earthquake responses are verified using the guidelines of Indian seismic codes. Results indicate that the outriggers contribute in significantly reducing the storey displacement and storey drift up to 28% and 20% respectively. Also, it is observed that the PSC outriggers are found to be more efficient over RCC outriggers. The optimum location of both types of outriggers is found to be at the mid height of building.

• Journal of Wind Energy
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• v.14 no.4
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• pp.50-56
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• 2023

With the abnormal weather phenomena caused by global warming, the frequency and intensity of lightning strikes are increasing, and lightning accidents are becoming one of the biggest causes of failures and accidents in offshore wind turbines. In order to secure generator operation reliability, effective and practical measures are needed to reduce lightning damage. Because offshore wind turbines are tall structures installed at sea, the possibility of direct lightning strikes is very high compared to other structures, and the role of surge protection devices to minimize damage to the electrical and electronic circuits inside the wind turbine is very important. In this study, a varistor, which is a key element for a class 1 surge protection device for direct lightning protection, was developed. The current density was improved by changing the varistor composition, and the distance between the electrode located on the varistor surface and the edge of the varistor was optimized through a simulation program to improve the fabrication process. Considering the combined effects of heat distribution, electric field distribution, and current density on the optimized varistor surface, silver electrodes were formed with a gap of 0.5 mm. The varistor developed in this study was confirmed to have an energy tolerance of 10/350 ㎲, 50kA, which is a representative direct lightning current waveform, and good protection characteristics with a limiting voltage of 2 kV or less.

• Clinical Nutrition Research
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• v.12 no.3
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• pp.177-183
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• 2023

Bariatric surgery is the most effective treatment for sustained weight reduction, and it can result in substantial improvements in the severity of type 2 diabetes, metabolic syndrome, nonalcoholic fatty liver disease, and quality of life. However, sleeve gastrectomy, a weight loss surgery that removes two-thirds of the stomach, reduces appetite and nutrient absorption, impairing digestion and the absorption of nutrients like iron, vitamin B₁₂, and protein-bound nutrients. This case study aims to demonstrate that patients undergoing sleeve gastrectomy require long-term and periodic monitoring of biochemical data, weight changes, and caloric and protein intake by a professional nutritionist to prevent malnutrition and nutritional deficiencies. In this case study, a 48-year-old woman was diagnosed with morbid obesity, hypertension, sleep apnea syndrome, and chronic gastritis. At initial evaluation, she was 160 cm tall and weighed 89 kg, with a body mass index of 34.8 kg/m². At 1 postoperative year, she consumed 650 kcal and 25 g of protein per day, the percentage of excess weight loss was 141.1%, and body mass index was 21 kg/m². Compared to preoperative levels, calcium and folic acid levels did not decrease after 1 postoperative year, but hemoglobin, ferritin, and vitamin B₁₂ levels decreased. In conclusion, when patients experience rapid weight loss after sleeve gastrectomy, follow-up should be frequent and long. Dietary education should be conducted according to digestive symptoms, and oral nutritional supplements, including vitamins and minerals.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.199-205
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• 2009

Recently, as the concern for the development of a construction method for an environmental protection and for tall building is increasing, the use of the half precast concrete(PC) slab that has the solution of environmental problems and the advantage such as reduction of construction period is being demanded. However, there is shortcoming that the crack can occur easily while constructing, and these cracks can have a bad influence upon the structural performance of PC composite slab. However, there is little studies on the influence of these cracks on the structural performance of composite PC slab. In this study, the specimen caused the crack before pouring topping concrete in the half PC slab and the PC composite slab without the cracks were produced to investigate the structural performance of PC composite slab with crack.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.73-87
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• 2018

A variety of micro meteorological variables such as air temperature, wind, solar radiation and latent heat at Gwangneung forests (conifer and broadleaved forests) and AWS (Automated Weather Station) of Pocheon urban area were used to quantify the air temperature reduction effect of forests, which is considered to be an eco-friendly solution for reducing the urban heat island intensity during summer. In June, July and August of 2016 and 2017, the average maximum air temperature differences between above and below canopy of forests, and between the forests and urban areas were $-1.9^{\circ}C$ and $-3.4^{\circ}C$ respectively, and they occurred at 17:00. However, there was no difference between conifer and broadleaved forests. The effect of air temperature reduction by the forests was positively correlated with accumulated evapotranspiration and solar radiation from 14:00 to 17:00 and showed a negative correlation with wind speed. We have developed a model to quantify the effect of air temperature reduction by forests using these variables. The nighttime air temperature reduction effect by forests was due to the generation of cold air from radiative cooling and the air temperature inversion phenomenon that occurs when the generated cold air moves down the side of mountain. The model was evaluated in Seoul by using 28 AWSs. The evaluation shows that the air temperature of each district in Seoul was negatively correlated with the area and size of the surrounding tall vegetation that drives vegetation evapotranspiration during the day. During the night, however, the size of the surrounding tall vegetation and the elevations of nearby mountains were the main influencing factors on the air temperature. Our research emphasizes the importance of the establishment and management of urban forests and the composition of wind roads from mountains for urban air temperature reduction.

• Journal of Preventive Medicine and Public Health
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• v.2 no.1
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• pp.5-22
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• 1969

The urban population of our country is rapidly increasing due to many factors of social structure, and sociologists are predicting that the increase rate of the urban population will be over 50% in 1980's. Above all, the population of the capital city of Seoul, is at present more than four millions. Such centring of people in cities, together with the improvement of the standards of living, caused rapid increase in the amount of fuel consumption, and this consumption of fuels became one of the primary sources of the air pollution in cities. Moreover, the heavy traffic, construction of many tall buildings, and the increasing number of new factories due to the industrial development-all these are contributing to make the matter of air pollution worse and worse in the Metropolitan, whose geographical location is quite unfavorable considered from the view point of air pollution. Most homes in Seoul use briquet as fuel, while oils are used in tall buildings. The CO, $SO_2$, and smoke that come from burning of these fuels are a great threat to the health of the urban population. With the purpose of examining the influence of air pollution upon the public health, written inquiries were made upon respiratory diseases, and the carboxyhemoglobin saturation in the blood was measured to determine whether the air pollution may affect the health of the urban population. Method of Health Examination (1) Investigation of Respiratory Diseases Patients' records were examined to figure out the monthly ambulance rate of respiratory patients to the total number of patients treated. On the other hand, by using the questionnaire form approved by the Medical Research Council's Committee on Research into Chronic Bronchitis, investigators interviewed the examinees and inquired into the respiratory symptoms. (2) Measuring of Carboxyhemoglobin Saturation From the ear lobe of the examinees, with the use of the melangeur for the white blood cell counting, blood was taken, and after diluting it ten times with 0.1% $Na{2}CO_{3}$, again diulting it 20 times with 0.5% $Na_{2}\;CO_{3}$, its absorbancy was measured. The following results are obtained from the investigation. (1) It was found out that 7.7% of the total patients under treatment were suffering from upper respiratory infection, acute or chronic bronchitis, bronchial asthma, pulmonary emphysema and bronchiectasis. Of them all, patients with upper respiratory infection numbered the greatest with 4.8% and patients with acute or chronic bronchitis the next with 2.1%, and their monthly ambulance rate was high from December to February during the winter, and from April to May and from September to October during the changeable seasons. (2) The daily ambulance rate of respiratory patients, it was revealed, had a close connection with the concentration of $SO_2$ and CO in the air. (3) It was found out that men were more subject to respiratory disease than women, and both men and women were more liable to the diseases with the advancing of age. (4) People living at Choong-ku with the heavy traffic and in the industrial zones of Yeungdungpo had high frequency of respiratory symptoms. (5) Considered from the view point of occupations, high frequency was found among those without job, with jobs unknown, merchants and intdustrial workers, whose social status was rather low and traffic policemen who were always exposed to the exhaust gas of cars. As for women, the frequency was detected in the order of those from high to low, housewives who were exposed to briquet gas, women with jobs unknown, women without jobs, whose social status was low. (6) Ex-smokers rather than smokers, of both sexes, had higher frequency. As for men, heavy smokers had high frequency, while in women light smokers had rather high frequency which was presumed to be due to their average old age. (7) Men's average of carboxyhemoglobin saturation was 9.48%, while women's was 11.3%, higher than men's. (p<0.05). Age meant no difference in the case of men, but as for women, the saturation was remarkably high between the ages from 20 to 60. (8) No regional difference was detected in the carboxyhemoglobin saturation. (9) The carboxyhemoglobin saturation was found, in the case of men, in the order of office workers, traffic policemen, students, the unemployed, merchants and industrial workers, drivers; and as for women, the order was housewives, office workers, merchants and industrial workers. (10) No significant correlation was found between the carboxyhemoglobin saturation and the concentration of CO detected in kitchens, or between the carhoxyhemoglobin saturation and the passing of time after exposure to briquet gas. No difference of carboxyhemoglobin saturation was detected between smokers and non-smokers, and the degrees of smoking; only, significant negative correlation was found between the passing of time after smoking and the carboxyhemoglobin saturation. It is ture that air pollution causes or aggravates the respiratory diseases, increases the carboxyhemoglobin saturation in the blood, but what seems to be more hazardous to the health is the air polluted by the briquet gas in the kitchens and on-dol rooms rather than the atmospheric air pollution.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.4
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• pp.252-257
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• 1991

In a two-year's field experiment, the effectiveness of magnesium-and boron-enriched complex fertilizer (CF, N-P$_2$O$_{5}$-K$_2$O-MgO-B$_2$O$_3$: 14-10-12-3-0.2) on the maintenance and management of hilly pasture was studied. The effects of CF and some straight fertilizers (SF) on forage yields, yield components, and chemical compositions were compared in a mixed grass-clover (orchardgrass, tall fescue, kentucky bluegrass, and ladino clover) and a pure grass (orchardgrass) swards. The results are summarized as follows: 1. Considerably higher average dry matter yields were obtained in the CF plots than in the SF plots. In the mixed sward, the yields of whole mixed forages were inclosed by 10.8-14.5%, grasses by 11%, and legume by 21.5-31.0% by the use of the CF over the use of SF. In the pure grass sward, the yield of grasses was increased by 7.0-21.8%. 2. The rates of yield increase due to the application of CF were dependent on such factors as types of sward (pure or mixed), application rates of NPK, and forage species. The increase of forage yields due to the CF was greater at the normal rate of NPK application than at lower application rate, and in legume forage than in grass forage. 3. The crude fiber, crude fat and NFE contents of forages were not significantly changed by different treatments. However, the forage of CF plot at the normal application rate of NPK contained relatively higher amount of crude protein and crude fat compared with the forages of other plots. 4. There were no significant differences in the contents of mineral nutrients in forages among the different treatments. In spite of the application of Mg-enriched CF, the contents of Mg in soils and forages were below the optimum level.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.173-182
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• 2007

The purpose of this study was to compared the early growth pattern, stem, leaf and root weight, DM yield, flowering characteristics and preference for selection of turf type grasses and wild flower species in mixtures combination for wildflower pasture. The experimental design included five species of turf grasses and 11 species of wildflower : turf type grass species{Kentucky bluegrass(Midnight), tall fescue(Millennium), perennial ryegrass(Palmer III), redtop(Barricuda) and creeping bentgrass(Crenshaw)}, wildflower species {Chrysanthemum leucanthemum L. Coreopsis lanceolata L., Rudbeckia bicolor Nutt.., Dianthus chinensis L., Chrysanthemum lindicum L., Lotus corniculatus var. Japonicus Regel, Veronica linariaefolia Pallas, Aster koraiensis Nakai., Chrysanthemum zanadskii var. latilobum (Maxim.) Kitamura, Lythrum anceps Makino and Iris pallassi var. chinensis Lodd}. The field trials were carried out on the experimental pasture plots of Chungnam National University from January 2005 to December 2006. The appropriate species of turf grass which have a mixture possibility with wildflower are thought to be Kentucky bluegrass. Compared with Kentucky bluegrass, on the other hand, species such as Chrysanthemum leucanthemum L., Lotus corniculatus var. Japonicus Regel, Chrysanthemum zanadskii var. latilobum Maxim.) Kitamura and Lythrum anceps Makino have shown advantageous aspects of fast early growth pattern and highly weights of stem, leaf and root. Futhermore, these wild flowers were in harmony and no overlap on flower color, flowering periods and flowering longevity, and highly preference by Korean native goats. For the establishment of wildflower pasture in Korea, therefore, it is important to select the appropriate species of turf glasses, which have a weak competition against wild flowers, and then to make mixture combination of those turf glasses with the various wild flowers which have a strong competition against turf glasses but have a different anthesis characteristics among themselves.