• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.261-269
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• 2023

During a nuclear power plant (NPP) accident, radioactive material may be released into the surrounding environment in the form of a radioactive plume. The behavior of the radioactive plume is influenced by meteorological factors such as wind direction and speed. If the residents are evacuated to a shelter in the direction of the flow of the radioactive plume, the radiation exposure of the residents may increase, contrary to the purpose of the evacuation. To avoid such an undesirable outcome, this paper applies a big data analysis to evaluate the suitability of the shelter locations near 5 NPPs in the Republic of Korea in terms of the seasonal wind direction frequency in those areas. To this end, the wind data measured around the NPPs from 2016 to 2020 were analyzed to derive the seasonal wind direction frequency using a big data analysis. These analyses results were then used to determine how many shelters around NPPs locate in areas with prevailing wind direction per season. Then, suggestions were made on the direction for residents not to evacuate, if possible, that is, the prevailing seasonal wind directions for 5 NPPs, depending on the season in which the accident occurs.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.126-133
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• 2019

In recent years, the deterioration of fruit quality caused by poor coloration and sunburn disorder has become serious problems in apple market, which is a result of the increase of surface temperature due to the abnormal temperature increase during summer season. This study was conducted to investigate the effect of wind net shading and fine water spray using sprinkler on fruit coloration, sunburn damage and overall fruit quality of 'Fuji' and 'Hongro' apples. Fifteen sprinklers (7L/hr) were installed at the orchard of the Chungcheongnam-do Agricultural Research and Extension Services, located in Sinam-myeon Chungcheongnam-do Korea, at a height of 3m above the apple tree of $1.5m{\times}3.5m$ north-south direction. Fine water spraying treatment was divided into day time spray (10:00 am to 6:00 pm) and all day spray (10:00 am to 10:00 pm) from early July to 10 days before harvest in 2017 and 2018 season, respectively. Temperature of the surface of apple fruit, characteristic of fruit, and degree of sunburn damage were investigated. In 'Fuji', the fruit surface temperature checked at 2 pm on August 10 was decreased considerably in the day time spray ($35.6^{\circ}C$) and wind net ($39.0^{\circ}C$) when compared with the untreated control ($44.4^{\circ}C$). Similarly, the fruit surface temperature also decreased considerably in the all day spray ($35.1^{\circ}C$) and wind net ($36.9^{\circ}C$) treatments when compared with the untreated control ($46.5^{\circ}C$) in 'Hongro' apples. The incidence of sunburn disorder was significantly decreased with day time spray (5.0%), all day spray (5.8%) and wind net (7.0%) when compared with untreated control (23.4%) in 'Fuji' apples. As a results, the treatment of fine water spray and wind net consequently showed 26% and 34% increase of redness ($a^*$) value in the skin color difference, respectively, in 'Fuji' apples.

• Wind and Structures
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• v.4 no.1
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• pp.73-84
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• 2001

Analysis of pressures measured on the roof of the full-scale Texas Tech building and a 1/50 scale model of a typical house showed that the pressure fluctuations on cladding fastener and cladding-truss connection tributary areas have similar characteristics. The probability density functions of pressure fluctuations on these areas are negatively skewed from Gaussian, with pressure peak factors less than -5.5. The fluctuating pressure energy is mostly contained at full-scale frequencies of up to about 0.6 Hz. Pressure coefficients, $C_p$ and local pressure factors, $K_l$ given in the Australian wind load standard AS1170.2 are generally satisfactory, except for some small cladding fastener tributary areas near the edges.

• Wind and Structures
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• v.16 no.4
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• pp.301-322
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• 2013

Recent major post-hurricane damage assessments in the United States have reported that the most common damages result from the loss of building roof coverings and subsequent wind driven rain intrusion. In an effort to look further into this problem, this paper presents a full-scale (Wall of Wind --WoW--) investigation of external and underneath wind pressures on roof tiles installed on a low-rise building model with various gable roofs. The optimal dimensions for the low-rise building that was tested with the WOW are 2.74 m (9 ft) long, 2.13 m (7 ft) wide, and 2.13 m (7 ft) high. The building is tested with interchangeable gable roofs at three different slopes (2:12; 5:12 and 7:12). The field tiles of these gable roofs are considered with three different tile profiles namely high (HP), medium (MP), and low profiles (LP) in accordance with Florida practice. For the ridge, two different types namely rounded and three-sided tiles were considered. The effect of weather block on the "underneath" pressure that develops between the tiles and the roof deck was also examined. These tests revealed the following: high pressure coefficients for the ridge tile compared to the field tiles, including those located at the corners; considerably higher pressure on the gable end ridge tiles compared to ridge tiles at the middle of the ridge line; and marginally higher pressure on barrel type tiles compared to the three-sided ridge tiles. The weather blocking of clay tiles, while useful in preventing water intrusion, it doesn't have significant effect on the wind loads of the field tiles. The case with weather blocking produces positive mean underneath pressure on the field tiles on the windward side thus reducing the net pressures on the windward surface of the roof. On the leeward side, reductions in net pressure to a non-significant level were observed due to the opposite direction of the internal and external pressures. The effect of the weather blocking on the external pressure on the ridge tile was negligible.

• Journal of Environmental Science International
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• v.16 no.1
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• pp.73-79
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• 2007

The purpose of this study is to clarify the effect of mountain-valley wind on heat island formed in urban area which is located around valley mouth. The meteorological observations were carried out over the Dalbi-valley under a clear summer pressure patterns, and some consideration were tried from the results. In order to make clear the climatological characteristics and air-mass modification process of the mountain-valley wind over the valley, the meteorological observations were done simultaneously at two points. The observational points were located at the breast and valley mouth parts, respectively. The results were as follows: First, it was found that the valley wind was observed through the daytime, and it was replaced by a mountain wind after sunset. Second, the heat budget is also investigated with observation data. The sensible heat flux over the breast of Dalbi-valley reached to about $200 W/m^2$ during daytime, which is a little more than one third of net radiation. On the other hand, the sensible heat flux represented negative values during nighttime. But the sensible heat flux over the valley mouth covered by asphalt showed plus value(about $20{\sim}30 W/m^2$) during the nighttime.

• Journal of the Korean Geophysical Society
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• v.8 no.3
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• pp.159-167
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• 2005

Turbulent fluxes of sensible heat and latent heat were analyzed at King Sejong station in the austral summer of 2002 (December) and 2003 (January and February). Monthly mean air temperatures of January and February (2.2oC) were similar to those averaged over 1988 to 2001. Precipitation was less in January and greater in February than those averaged over last 14 years. In December of 2002 and January, there was precipitation primarily when easterly wind blew usually. The frequency of snowfall was equal to or larger than that of rainfall. In the mean while, precipitation primarily in forms of rainfall occurred with westerly wind in February. In addition, while for easterly wind, temperature and humidity was low, temperature and humidity were high in case of westerly wind. Based on flux footprint, measured flux mainly came from within 300 m with maximum of 40 m upwind, indicating the insignificant role of the sea around the study site. Half-hourly downward short wave radiation amounted up to ∼ 1000 Wm-2 and net radiation ranged from -50 to 600 Wm-2. Half-hourly sensible heat flux was positive at daytime with maximum of ∼ 400 Wm-2, except the 27th and 28th in February of 2003 when it was negative all day despite of positive net radiation at short daytime. Latent heat flux was positive with maximum of ∼ 130 Wm-2. Depending on wind direction, the partitioning of net radiation into the sum of sensible heat flux and latent heat flux was larger than 0.8, indicating the strong source of the land surface for the atmospheric heating. The daytime averaged Bowen ratio (=sensible heat flux /latent heat flux) was significantly greater than 1, indicating that sensible heat flux was the main source to heat the atmosphere over the site.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.105-111
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• 1999

To investigate the relationships between ocean environmental characteristics and thechange of the catch, we analyzed various environmental factors such as mean temperature, salinity, current vectors, lunar day and wind vectors from 1995 to 1996 and the catch fluctuation of Hanlim set net from 1994 to 1996. The results are as follow ; 1) The proportion of fishes caught in Hanlim set net is highest for horse mackere1 ($69.2\%$) and is followed by common mackerel ($18.4\%$), hair tail ($5.6\%$), squid ($2.7\%$) and rabbit fish ($1.4\%$) in order. Two peaks in the monthly catch appeared in June and October in the operation period of May- December. 2) The flow direction was northward in flood time and southeastward in ebb time around the Hanlim set net. Thus, the vortical mixing of sea water was active and continued for more than 3 hours. In addition, mean daily temperature was low due to the presence of middle and bottom water in offshore. Increase in salinity or high salinity of sea water provides a favorable condition for catches of fishes. Catches in the first quarter and the last quarter of the moon were larger than that in full moon and the last of the month. In particular, when south or southeasterly wind velocity reaches about 3$\~$6.5 m/s, the possibility of catches increases.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.397-408
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• 2006

Due to the temporal and spatial variability of the warming at and near the Antarctic Peninsular, it is required to better understand local climate at the issued region. The purpose of the study are to characterize surface radiation, air temperature and wind direction and investigate their relations at the King Sejong Station near the Antarctic Peninsular during last three and half years. While the study site was a weak radiative energy sink (positive net radiation) with annual mean of 15-20 Wm-2, it played a role as a strong sink in summer (December to January) with mean of 85 Wm-2, a magnitude that was significantly larger than those at other surface covered with snow or ice in Antarctica. Monthly averaged air temperature ranged from -7.7-2.8oC and the variations of monthly averaged air temperature showed the distinct differences with year. Northwesterly, westerly and easterly were dominant and the variability of air temperature could be explained by the variability of the frequency of wind direction with cold easterly and warm northwesterly/northerly to some degree, which in turn influenced radiation budget through albedo in summer.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.4
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• pp.354-361
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• 2023

In this study, the AHP (analytic hierarchy process) technique was used to analyze the risk of expected risk factors and fishing possibilities during gillnet fishing within the floating offshore wind farms (floating OWF). For this purpose, the risks that may occur during gillnet fishing within the floating offshore wind farms were defined as collisions, entanglements, and snags. In addition, the risk factors that cause these risks were classified into three upper risk factors and ten sub risk factors, and the three alternatives to gillnet fishing available within the floating OWF were classified and a hierarchy was established. Lastly, a survey was conducted targeting fisheries and marine experts and the response results were analyzed. As a result of the analysis, among the top risk factors, the risk was the greatest when laying fishing gear. The risk of the sub factors for each upper risk was found to be the highest at the berthing (mooring), the final hauling of fishing net, and the laying of the bottom layer net. Based on the alternatives, the average of the integrated risk rankings showed that allowing full navigation/fisheries had the highest risk. As a result of the final ranking analysis of the integrated risk, the overall ranking of allowing navigation/fisheries in areas where bottom layer nets were laid was ranked the first when moving vessels within the floating OWF was analyzed as the lowest integrated risk ranking of the 30th at the ban on navigation/fisheries. Through this, navigation was analyzed to be possible while it was analyzed that the possibility of gillnet fishing within the floating OWF was not high.

• Wind and Structures
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• v.12 no.4
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• pp.383-400
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• 2009

Low rise building roofs can be subjected to large fluctuating pressures during a tropical cyclone resulting in fatigue failure of cladding. Following the damage to housing in Tropical Cyclone Tracy in Darwin, Australia, the Darwin Area Building Manual (DABM) cyclic loading test criteria, that loaded the cladding for 10000 cycles oscillating from zero to a permissible stress design pressure, and the Experimental Building Station TR440 test of 10200 load cycles which increased in steps to the permissible stress design pressure, were developed for assessing building elements susceptible to low cycle fatigue failure. Recently the 'Low-High-Low' (L-H-L) cyclic test for metal roofing was introduced into the Building Code of Australia (2007). Following advances in wind tunnel data acquisition and full-scale wind loading simulators, this paper presents a comparison of wind-induced cladding damage, from a "design" cyclone proposed by Jancauskas, et al. (1994), with current test criteria developed by Mahendran (1995). Wind tunnel data were used to generate the external and net pressure time histories on the roof of a low-rise building during the passage of the "design" cyclone. The peak pressures generated at the windward roof corner for a tributary area representative of a cladding fastener are underestimated by the Australian/New Zealand Wind Actions Standard. The "design" cyclone, with increasing and decreasing wind speeds combined with changes in wind direction, generated increasing then decreasing pressures in a manner similar to that specified in the L-H-L test. However, the L-H-L test underestimated the magnitude and number of large load cycles, but overestimated the number of cycles in the mid ranges. Cladding elements subjected to the L-H-L test showed greater fatigue damage than when experiencing a five hour "design" cyclone containing higher peak pressures. It is evident that the increased fatigue damage was due to the L-H-L test having a large number of load cycles cycling from zero load (R=0) in contrast to that produced during the cyclone.