• Transactions of Materials Processing
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• v.14 no.8 s.80
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• pp.675-680
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• 2005

This study was aimed at the design of the dies for the automobile part for the engine oil leakage prevention using the computer simulation to shorten the period of production, on the basis of the process planning which was designed by the field experts. In the computer simulation,'eesy-2-form' of 2D FEM simulation package and 'eesy-DieOpt' have been used, which are the commercial process analysis and die design program. Through the simulation of 'eesy-2-form', we could know the propriety of the forming process, the inner pressure of the die and the suitable fitting pressure between the insert and the sleeve which was not showing any positive tangential stresses in the insert. Through the simulation of 'eesy-DieOpt', we could know the number of the stress ring, the diameter ratios, the stresses of the die, the shrink fitting tolerance and temperature in the condition of the already determined maximum outer die diameter of the multi-stage former. The validity of the die design using the computer simulation was analyzed by the experiments and the results were satisfactory. As the results of this study, the new and easy die design system for cold forging has been developed.

• Atmosphere
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• v.23 no.4
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• pp.401-412
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• 2013

East Asia experienced extremely cold weather in January 2011, while the previous December and the following February had normal winter temperature. In this study National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data are used to investigate the characteristic features observed in the meteorological fields such as temperature, sea-level pressure, geopotential height, and wind during this winter period. In January the planetary-wave pattern is dominated by stationary-wave form in the mid-to-high latitude region, while transient waves are significant in the previous month. To understand the planetary-wave features quantitatively, harmonic analyses have been done for the 500-hPa geopotential height field. In the climatological-mean geopotential heights the wave numbers 1, 2, and 3 are dominant during the whole winter. In January 2011 the waves of number 1, 2, and 3 are dominant and stationary as in the climatological-mean field. In December 2010 and February 2011, however, the waves of number 4, 5, and 6 play a major role and show a transient pattern. In addition to the distinctive features in each month the planetary-wave patterns dependent on the latitude are also discussed.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.4
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• pp.409-417
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• 2012

External pathogens such as wind, cold can easily invade the external parts of the body when host's external defense ability is not secure. Herein, we consider the underlying mechanisms against the external contraction at the body surface. During the early period after primary invasion, external defense mechanisms are gradually activated. The classic clinical manifestations are aversion to cold, fever, headache, generalized pain, and nasal congestion. This condition is called by invasion of external pathogen into the body surface. As the disease progress, lung qi is stagnated and thereby up-outward and downward movement action of lung become disturbed. Therefore, when doctor administrate formula to treat the exterior syndrome, doctor must keep in mind not only materia medica, but also underlying mechanisms through which many clinical symptoms appear.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.164-169
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• 2004

A spatial interpolation scheme incorporating local geographic potential for cold air accumulation (TOPSIM) was used to test the feasibility of operational frost warning in Chatancheon basin in Yeoncheon County, where the introduction of new crops including temperate zone fruits is planned. Air temperature from April to June 2003 was measured at one-minute intervals at four locations within the basin. Cold-air accumulation potentials (CAP) at 4 sites were calculated for 3 different catchment scales: a rectangular area of 65 x 55 km which covers the whole county, the KOWACO (Korea Water Corporation) hydrologic unit which includes all 4 sites, and the sub-basins delineated by a stream network analysis of the digital elevation model. Daily minimum temperatures at 4 sites were calculated by interpolating the perfect prognosis (i.e., synoptic observations at KMA Dongducheon station) based on TOPSIM with 3 different CAPs. Mean error, mean absolute error, and root mean square error were calculated for 45 days with no precipitation to test the model performance. For the 3 flat locations, little difference was detected in model performance among 3 catchment areas, but the best performance was found with the CAPs calculated for sub-basins at one site (Oksan) on complex terrain. When TOPSIM loaded with sub-basin CAPs was applied to Oksan to predict frost events during the fruit flowering period in 2004, the goodness of fit was sufficient for making an operational frost warning system for mountainous areas.

• Fashion & Textile Research Journal
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• v.12 no.4
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• pp.513-522
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• 2010

The aim of this study is to investigate the actual state for the development of the thermally comfortable uniform for workers on a low temperature storage. Observation, interview and survey were executed focusing on the environment, clothing, and human factors which have effects on the comfort of workers. Of 400 distributed, 253 questionnaires were analyzed through descriptives, frequency, ANOVA, t-test, multi-response analysis, correlation analysis with SPSS 12.0. The results are following. Coming and going between a selling area and cold storages, the workers showed to experience a big temperature gap. They indicated to feel cold on face and hands which were not covered by clothing and have got sick because of low temperature. The workers wanted the uniform made of functional fabrics, especially heat insulation fabrics. Female workers rather than male workers, the older, and the longer their working period were, the more uncomfortable they revealed to feel. The workers who works on the daily products part or mainly on the freezer appeared to feel cold more than any other workers. In conclusion, it was found that the uniform which consider steady state and unsteady state heat transfer together must be developed.

• Earthquakes and Structures
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• v.4 no.6
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• pp.629-647
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• 2013

Loading protocols have been developed for quasi-static cyclic testing of structures and components. However, it is uncertain if protocols developed for conditions of intense ground shaking in regions of high seismicity would also be applicable to regions of low-moderate seismicity that are remote from the tectonic plate boundaries. This study presents a methodology for developing a quasi-static cyclic displacement loading protocol for experimental bracing evaluation of cold-formed steel stud shear walls. Simulations presented in the paper were based on conditions of moderate ground shaking (in Australia). The methodologies presented are generic in nature and can be applied to other regions of similar seismicity conditions (which include many parts of China, Korea, India and Malaysia). Numerous response time histories including both linear and nonlinear analyses have been generated for selected earthquake scenarios and site classes. Rain-flow cycle counting method has been used for determining the number of cycles at various ranges of normalized displacement amplitude. It is found that the number of displacement cycles of the loading protocol increases with increasing intensity of ground shaking (associated with a longer return period).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.131-132
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• 2023

In this paper, standard specification of heat curing section of cold weather concrete between Korea and China were compared. First, Korea concrete specification (KCS 14 20 40) stipulates that the application period is less than 4℃ per day or less than 0℃ per day right after pouring, but in China, the outdoor daily average temperature is less than 5℃ for five consecutive days. This is believed to be due to the difference in temperatures between Korea and China in winter. Next, in the case of Korea, KCS do not show that the concrete temperature in curing should be 5℃ or higher to prevent early frost damage and obtain the minimum required compressive strength. On the other hand, in the case of China, the specificaion does not show that the curing method is selected based on the concrete surface coefficient after considering the outdoor temperature. In addition, in Korea and China regulation, the temperature of the space during thermal curing was shown to be similar.

• Journal of the Korea Institute of Building Construction
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• v.8 no.2
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• pp.107-112
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• 2008

According to Korean Architectural Standard Specification (KASS) , at the design stage of the specified concrete strength, strength correction with each temperature level should be considered to secure required strength at 28 days even in low temperature condition, In this paper, the period for the strength correction at the stage of mixture design of the concrete using ordinary Portland cement(OPC) specified in KASS was determined with each region of south Korea based on the meteorological data of KMA(Korea meteorological administration) by applying KASS-5 regulation. In case of 28 days of strength control age, the period for strength correction with 6MPa was calculated to $50{\sim}60$ days and, with 3 MPa. to around 80 days. The period for the strength correction was shown to be decreased with the rise of altitude. The period to consider the delay of the strength development due to low temperature including the period of cold weather concrete was nearly 7 months around 1 year. References for determining the strength correction factors with each region of south Korea was provided in this paper. Further investigation of strength correction of the concrete containing blended cement is to studied.

• Journal of Aquaculture
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• v.10 no.2
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• pp.189-197
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• 1997

A series of short (8 hours) and long term (96 hours) exposure studies was conducted on a laboratory scale to evaluation (1) the threshold concentrations of petroleum hydrocarbon in seawater which can lead to tainting problems in yellow tail (Seriola quinqueradiata) and (2) the time to recover (depuration period) once the tainting has occurred. The water-soluble fraction (WSF) of crude oil was prepared by stirring the oil with cold seawater. The main component of the WSF were low-boiling aromatics, although these were only al small proportion of the starting oil. From the sencory evaluation it was concluded that the threshold hydrocarbon levels in seawater which will impart a taint in yellow tail fillets within a 8-hour exposure period (short exposure period) are in the range of 0.4 to 1.0 ppm and within a 96-hour exposure period (long exposure period) are in the range of 0.2 to 0.5 ppm. Depuration trials were carried out with WSF from crude oil. The fish were exposed for 48 hours to concentration of 2.5 ppm hydrocarbons. After 48-hour exposure period, the fish were allowed to depurate in fresh, uncontaminated seawater. Depuration time for these fish was 10 days. The taste panelists were able to detect the contaminated fillets very easily while the depurated fish could not be distiguished from the control.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.289-296
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• 2009

The appearance and variation of cold water area and its expansion mechanism of tidal front in the south western coast of Korea in summer were studied on the basis of oceanographic data(1966-1995), satellite images from NOAA and SeaWiFs and numerical model. Cold water appearance in southwestern field of Jindo was due to the vertical mixing by strong tidal current. Tidal front where horizontal gradient of water temperature was more than $0.3^{\circ}C$/km parallels to contours of H/$U^3$ parameter 2.0~2.5 and the outer boundary of cold water region corresponds with contours of the parameter 2.5~3.0 in the southwestern sea of Korea during the period between neap and spring tides. The position replacement of tidal front formed in the study ares varies in a range of 25~75km and cold water region extends about 90km. These suggest that the magnitude of variation of frontal position and cold water area was proportionate to the tidal current during lunar tidal cycle. Moreover, it was estimated that the southwestward expansion of cold water region was derived from the southwestward tide-induced residual currents with speed more than 10cm/s.