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Continuous work in high-temperature environments can lead to occupational injuries, illnesses, and even deaths. Thus, mandatory rest time for appropriate heat management programs must be provided for the safety of workers. In this study, we figured out the minimum rest time for the heat safety of outdoor workers in South Korea. To quantitatively calculate the minimum rest time, the wet-bulb globe temperature (WBGT) index estimated by 27 synoptic weather stations in South Korea and the national work-rest regimens were used. We assumed that the minimum rest time is the same as the rest time of the work-rest regimens recommended by the WBGT. To examine the intra-seasonal evolution patterns of the minimum rest time, summer seasons are divided into several sub-periods. The average of the hourly WBGT values during summer months from June to August (2009–2018) shows that outdoor workers with a moderate workload (200–350 kcal/h) are exposed to heat stress during approximately 30% of their daytime working hours (06:00–18:00). In the whole summer period, the minimum rest time required for each hour was about 5 minutes for moderate work. But in the mid-summer period from late July to early August, the daily minimum rest time for moderate workload noticeably increases to 20 minutes of mid-day (11:00–15:00). Regionally, no significant increase in rest time was found in areas with high urbanization rates.

Severe spatiotemporal heterogeneity of emissions sources and limited measurement networks have been hampering the monitoring and understanding of CO2 fluxes in large cities, a great concern in climate research as big cities are among the major sources of anthropogenic CO2 in the climate system. To understand the CO2 fluxes in Seoul, Korea, CO2 fluxes at eight surface energy balance sites, six urban (vegetation-area fraction 60%), for 2017–2018 are analyzed and attributed to the local land-use and business types. The analyses show that the CO2 flux variations at the suburban sites are mainly driven by vegetation and that the CO2 flux differences between the urban and suburban sites originate from the differences in the vegetation-area fraction and anthropogenic CO2 emissions. For the CO2 fluxes at the urban sites; (1) vehicle traffic (traffic) and heating-fuel consumption (heating) contribute > 80% to the total, (2) vegetation effects are minimal, (3) the seasonal cycle is driven mainly by heating, (4) the contribution of heating is positively related to the building-area fraction, (5) the annual total is positively (negatively) correlated with the commercial-area (residential-area) fraction, and (6) the traffic at the commercial sites depend further on the main business types to induce distinct CO2 flux weekly cycles. This study shows that understanding and estimation of CO2 fluxes in large urban areas require careful site selections and analyses based on detailed consideration of the land-use and business types refined beyond the single representative land-use type widely-used in contemporary studies.

To understand the Korean Peninsula's carbon dioxide (CO 2 ) emissions and sinks as well as those of the surrounding region, we used 70 flask-air samples collected during May 2014 to August 2016 at Anmyeondo (AMY; 36.53 ∘ N, 126.32 ∘ E; 46 m a.s.l.) World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) station, located on the west coast of South Korea, for analysis of observed 14 C in atmospheric CO 2 as a tracer of fossil fuel CO 2 contribution ( Cff ). Observed 14 C ∕ C ratios in CO 2 (reported as Δ values) at AMY varied from −59.5 ‰ to 23.1 ‰, with a measurement uncertainty of ±1.8 ‰. The derived mean value Cff of ( 9.7±7.8 ) µ mol mol −1 ( 1σ ) is greater than that found in earlier observations from Tae-Ahn Peninsula (TAP; 36.73 ∘ N, 126.13 ∘ E; 20 m a.s.l., 28 km away from AMY) of ( 4.4±5.7 ) µ mol mol −1 from 2004 to 2010. The enhancement above background mole fractions of sulfur hexafluoride ( Δx(SF6) ) and carbon monoxide ( Δx(CO) ) correlate strongly with Cff ( r>0.7 ) and appear to be good proxies for fossil fuel CO 2 at regional and continental scales. Samples originating from the Asian continent had greater Δx(CO) : Cff(RCO) values, ( 29±8 ) to ( 36±2 ) nmol µ mol −1 , than in Korean Peninsula local air (( 8±2 ) nmol µ mol −1 ). Air masses originating in China showed ( 1.6±0.4 ) to ( 2.0±0.1 ) times greater RCO than a bottom-up inventory, suggesting that China's CO emissions are underestimated in the inventory, while observed RSF6 values are 2–3 times greater than inventories for both China and South Korea. However, RCO values derived from both inventories and observations have decreased relative to previous studies, indicating that combustion efficiency is increasing in both China and South Korea.

A 307-m tall meteorological tower was used to evaluate meteorological observation data obtained using a rotary-wing unmanned aerial vehicle (UAV). A comparative study between the tower and UAV observations was conducted during the daytime (06:00 to 19:00 local time (LT)) in the summer of 2017 (16&ndash, 18thAugust). Hourly vertical profiles of air temperature, relative humidity, black carbon (BC), and ozone (O3) concentrations were obtained for up to 300 m height. Statistical metrics for evaluating the accuracy of UAV observations against the tower observation showed positive (potential temperature) and negative (relative humidity) biases, which were within acceptable ranges. The daytime evolution of the lower atmospheric boundary layer (ABL) was successfully captured by the hourly UAV observations. During the early morning, a large vertical slope of potential temperature was observed between 100 and 140 m, corresponding to the stable ABL height. The large vertical slope coincided with the large differences in BC and O3 concentrations between altitudes below and above the height. The transition from stable to convective ABL was observed at 10&ndash, 11 LT, indicated by the ABL height higher than 300 m in the convective ABL. Finally, we provide several recommendations to reduce uncertainties of UAV observation.

The springtime dust events in Northeast Asia pose many economic, social, and health-related risks. Statistical models in the forecasting of seasonal dust events do not fully account for environmental variations in dust sources due to climate change. The Korea Meteorological Administration (KMA) recently developed the GloSea5-ADAM, a numerically based seasonal dust forecasting model, by incorporating the Asian Dust and Aerosol Model (ADAM)&rsquo, s emission algorithm into Global Seasonal Forecasting Model version 5 (GloSea5). The performance of GloSea5 and GloSea5-ADAM in forecasting seasonal Asian dust events in source (China) and leeward (South Korea) regions was compared. The GloSea5-ADAM solved the limitations of GloSea5, which were mainly attributable to GloSea5&prime, s low bare-soil fraction, and successfully simulated 2017 springtime dust emissions over Northeast Asia. The results show that GloSea5-ADAM&rsquo, s 2017 and 2018 forecasts were consistent with surface PM10 mass concentrations observed in China and South Korea, while there was a large gap in 2019. This study shows that the geographical distribution and physical properties of soil in dust source regions are important. The GloSea5-ADAM model is only a temporary solution and is limited in its applicability to Northeast Asia, therefore, a globally applicable dust emission algorithm that considers a wide variety of soil properties must be developed.

To understand Korea's carbon dioxide (CO2) emissions and sinks as well as those of the surrounding region, we used 70 flask-air samples collected during May 2014 to August 2016 at Anmyeondo (AMY, 36.53° N, 126.32° E; 46 m a.s.l.) World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) station, located on the west coast of South Korea, for analysis of observed 14C in atmospheric CO2 as a tracer of fossil fuel CO2 contribution (Cff). Observed 14C / C ratios in CO2 at AMY varied from −59.5 to 23.1 ‰ with the measurement uncertainty of ±1.8 ‰. The derived mean value Cff of (9.7 ± 7.8) μmol mol−1 (1σ) is greater than that found in earlier observations from Tae-Ahn Peninsula (TAP, 36.73° N, 126.13° E, 20 m a.s.l., 24 km away from AMY) of (4.4 ± 5.7) μmol mol−1 from 2004 to 2010. The enhancement above background of sulfur hexafluoride (Δx(SF6)) and carbon monoxide (Δx(CO)) correlate strongly with Cff (r > 0.7) and appear to be good proxies for fossil fuel CO2 at regional and continental scales. Samples originating from the Asian continent had greater Δx(CO) : Cff (RCO) values, (29 ± 8) to (36 ± 2) nmol μmol−1, than in Korean local air ((8 ± 2) nmol μmol−1). Air masses originating in China showed (1.8 ± 0.2) times greater RCO than a bottom-up inventory suggesting that China's CO emissions are underestimated in the inventory. However, both RCO derived from inventories and observations have decreased relative to previous studies, indicating that combustion efficiency is increasing in both China and South Korea.

BackgroundIt is important to quantify changes in CO2sources and sinks with land use and land cover change. In the last several decades, carbon sources and sinks in East Asia have been altered by intensive land cover changes due to rapid economic growth and related urbanization. To understand impact of urbanization on carbon cycle in the monsoon Asia, we analyze net CO2exchanges for various land cover types across an urbanization gradient in Korea covering high-rise high-density residential, suburban, cropland, and subtropical forest areas.ResultsOur analysis demonstrates that the urban residential and suburban areas are constant CO2sources throughout the year (2.75 and 1.02 kg C m−2 year−1at the urban and suburban sites), and the net CO2emission indicate impacts of urban vegetation that responds to the seasonal progression of the monsoon. However, the total random uncertainties of measurement are much larger in the urban and suburban areas than at the nonurban sites, which can make it challenging to obtain accurate urban flux measurements. The cropland and forest sites are strong carbon sinks because of a double-cropping system and favorable climate conditions during the study period, respectively (− 0.73 and − 0.60 kg C m−2 year−1at the cropland and forest sites, respectively). The urban area of high population density (15,000 persons km−2) shows a relatively weak CO2emission rate per capita (0.7 t CO2 year−1 person−1), especially in winter because of a district heating system and smaller traffic volume. The suburban area shows larger net CO2emissions per capita (4.9 t CO2 year−1 person−1) because of a high traffic volume, despite a smaller building fraction and population density (770 persons km−2).ConclusionsWe show that in situ flux observation is challenging because of its larger random uncertainty and this larger uncertainty should be carefully considered in urban studies. Our findings indicate the important role of urban vegetation in the carbon balance and its interaction with the monsoon activity in East Asia. Urban planning in the monsoon Asia must consider interaction on change in the monsoon activity and urban structure and function for sustainable city in a changing climate.

Ice nucleation processes by silver iodide were parameterized and implemented into the Weather Research and Forecasting model to perform winter orographic cloud seeding experiment in an eastern mountainous region of the Korean Peninsula. Cloud seeding at a mountain site resulted in production of ice crystals, mostly by deposition and condensation freezing nucleation of seeding material and depletion of water drops by ice crystals themselves and by snow and graupel particles grown from these ice crystals but importantly precipitation increased over the target area to the west of the seeding site. Sensitivity test showed that increasing the release rate of seeding material led to enhanced precipitation. Interestingly, dominant ice crystal nucleation mode was different for different aerosol concentrations: deposition and condensation freezing nucleation were dominantly responsible for ice crystal formation for maritime aerosol type (i.e., low concentration) while the dominant mode was contact freezing nucleation for continental aerosol type (i.e., high concentration). When seeding material was released at a low-altitude site (i.e., upslope of mountain), it was not successfully transported upward to the target area but instead dispersed along the direction of the mountain ridges by the barrier jets.

The purpose of this study was to investigate the impact of ground-based glaciogenic seeding on orographic clouds in the Daegwallyeong area on 13 March, 2013. The experiments was conducted by releasing silver iodide (AgI) under following conditions: surface temperature below , wind direction between 45 and , and wind speed less than . Two seeding rates, (SR1) and (SR2), were tested to obtain an appropriate AgI ratio for snowfall enhancement in the Daegwallyeong area. Numerical simulations were carried out by using the WRF (Weather Research and Forecast) model with AgI point-source module which predicted dispersion fields of AgI particles. The results indicated that the target orographic clouds contained adequate amount of supercooled liquid water and that the dispersion of AgI particles tended to move along the prevailing wind direction. To validate the seeding effects, the observation data from FM-120 and MPS as well as PARSIVEL disdrometer were analyzed. In this case study, glaciogenic seeding significantly increased the concentration of small ice particles below 1 mm in diameter. The observation results suggest that SR1 seeding be reasonable to use the ground-based seeding in the Daegwallyeong area.

광주과학기술원의 다파장 라만 라이다를 이용한 에어로졸 연속관측이 2009년부터 2011년까지 3년간 수행되었다. 장기 연속 관측을 통해 얻어진 라이다 신호들의 분석을 통해 편광소멸도를 산출해 내었고, 편광소멸도를 통하여 황사 층을 구분해 내었다. 구분된 황사의 층의 광학적 특징들이 관측 고도에 따라 다르다는 것을 신호의 분석으로부터 밝혀졌다. 이러한 광학적 특징의 차이를 규명하기 위하여, HYSPLIT 모델을 이용하여 각각 관측된 황사 층들의 유입 경로와 이동 중 고도를 분석하였다. 이러한 황사의 관측 고도에 따른 광학적 특성의 변화는 황사가 장거리 이동 중 통과한 오염물질 발생 지역에서 발생한 오염물질과의 혼합으로부터 기인한 것으로 사료된다. 특히 오염물질 발생 지역을 지날 때의 황사 층의 고도는 황사의 광학적 특성 변화에 가장 큰 영향을 미치는 것으로 판단된다. 3년간 라이다 관측 시스템으로 관측한 황사 중, 중국 산업지역 및 인구밀집도가 높은 지역 등과 같은 인위적 기원의 오염물질 발생 지역을 통과할 때의 고도가 1km 이하 일 때, 0.12 ± 0.01의 낮은 편광소멸도, 355 nm와 532 nm 파장에서 각각 67 ± 9 sr, 68 ± 9 sr 의 낮은 라이다비, 1.05 ± 0.57의 낮은 옹스트롬 지수(Angstrom expon) 보였으며, 이는 오염물질이 갖는 광학적 특성 값과 유사하다. 이와 반면 황사가 3 km 이상의 높은 고도로 오염물질 발생 지역을 통과한 경우는 0.21±0.09의 편광소멸도, 355 nm와 532 nm 파장에서 각각 48 ± 5 sr, 46 ± 4 sr 의 라이다 비, 0.57 ± 0.24 의 옹스토롬 지수를 보이며 이는 순수황사의 광학적 특성과 유사하다. 이는 황사가 중국 오염물질 발생지역을 통과할 때의 고도가 혼합상태의 황사 전체의 광학적 특성에 큰 영향을 미치는 것으로 판단되며, 낮은 고도에서는 오염물질과의 혼합의 정도가 증가하여, 오염물질의 광학적 특성이 우세하게 나타나는 반면, 높은 고도에서는 오염물질과 황사의 혼합이 상대적으로 적게 일어난다고 사료된다.

Surface energy balance closure has been examined using eddy covariance measurements and other observations at one industrial and three agricultural sites near the Nakdong River during daytime. Energy balance closure was evaluated by calculating the long-term averaged energy balance ratio (EBR), the ratio of turbulent energy fluxes to available energy, and the statistical regression of turbulent energy fluxes against available energy using half-hourly data. The EBR of all sites ranges from 0.46 to 0.83 while the coefficient of determination (R 2) ranges from 0.37 to 0.77. The energy balance closure was relatively poor compared to homogeneous sites, indicating the influence of surface heterogeneity. Unmeasured heat storage terms also seem to play a role in the surface energy budget at the industrial and irrigated sites. The energy balance closure was better in conditions of high wind speed, low downward short wave radiation, and high friction velocity, which suggests the role of heat storage term and surface heterogeneity in surface energy balance at these sites. Spectrum analysis shows a sharp roll-off at the low frequency in co-spectrum, which indicates that low-frequency motions do not significantly contribute to turbulent fluxes. Both the spectra and cospectra in unstable conditions show a broad peak indicating the influence of multiple sizes of large eddies over heterogeneous sites. Most of ogive curves for the kinematic latent and sensible heat fluxes reach an asymptote within 30 minutes regardless of the EBR value, indicating that low frequency motion is not a main factor for energy imbalance. However, stationary eddies due to landscape heterogeneity still remains as a possible cause for energy imbalance.

A kind of field bus called Actuator and Sensor interface bus(AS-i) was designed in this paper. The configuration of AS-i network system used Application Specific Integrated Circuit(ASIC) SAP5S chip and PLC S7-200 station, which included CPU 224 and AS-i master module CP 243-2. We also created an example program for PLC S7-200 to control AS-i network. The fire and smoke detection system was made with AS-i network system that was designed. This system had got more advantages than other system such as number of stations, easy installation, wide working area, etc. And designed system can be used as a partner network for higher level field bus networks.

This study investigates energy fluxes measured near Gangjeong-Goryeong Weir of the Nakdong River of South Korea for more than a year, from July 2011 to September 2012, in order to analyze the applicability of the data for future impact analyses. Each of the two study sites is located in a rural area, surrounded by agricultural fields, and an urban industrial area. Sensible and latent heat fluxes are analyzed according to the wind direction. In the summertime, when the wind blows from the river, sensible heat tends to decrease and latent heat tends to increase at both sites. This result is considered to be caused by moisture transfer from the river. Bowen ratio, energy balance closure, momentum flux, and stability are analyzed as well. The Bowen ratio of the rural agricultural site turns out higher than that of the urban site regardless of the season. The energy balance closure is higher at the agricultural site compared to the urban area, which is mainly due to exclusion of the storage term calculation at the urban site. The momentum flux is greater at the urban site both in winter and summer. The instability lasts longer during daytime and in the summertime, when there is a strong turbulence. The data from these sites are appropriate to be used in analyzing the impact of river in surrounding areas for future studies.

It is one of the most important to protect the battery over charging for stable use and to extend the life of battery which occurs with repeated charging and discharging. Various research have been studied to know the state of health, and in this paper the terminal voltage of battery is measured to calculate the state of charge simply. The circuit used comparator is designed and built not to fall under the specific voltage of battery. The designed circuit board is attached to the automatic water sanitizer device with a solar power system. The system is located in the water tank where there is not water and electric service, and confirmed that the state of working is good.

Mongolia`s solar-meteorological resources map has been developed using satellite data and reanalysis data. Solar radiation was calculated using solar radiation model, in which the input data were satellite data from SRTM, TERA, AQUA, AURA and MTSAT-1R satellites and the reanalysis data from NCEP/NCAR. The calculated results are validated by the DSWRF (Downward Short-Wave Radiation Flux) from NCEP/NCAR reanalysis. Mongolia is composed of mountainous region in the western area and desert or semi-arid region in middle and southern parts of the country. South-central area comprises inside the continent with a clear day and less rainfall, and irradiation is higher than other regions on the same latitude. The western mountain region is reached a lot of solar energy due to high elevation but the area is covered with snow (high albedo) throughout the year. The snow cover is a cause of false detection from the cloud detection algorithm of satellite data. Eventually clearness index and solar radiation are underestimated. And southern region has high total precipitable water and aerosol optical depth, but high solar radiation reaches the surface as it is located on the relatively lower latitude. When calculated solar radiation is validated by DSWRF from NCEP/NCAR reanalysis, monthly mean solar radiation is 547.59 MJ which is approximately 2.89 MJ higher than DSWRF. The correlation coefficient between calculation and reanalysis data is 0.99 and the RMSE (Root Mean Square Error) is 6.17 MJ. It turned out to be highest correlation (r

Wind power density distribution over the North Korea territory was investigated by using 30-year wind observations at 27 meteorological stations. The mean annual wind power density over North Korea turned out to be 58.6 W/m 2 , which corresponds to the wind power class of 1. The wind power density shows a seasonal variation, having the highest density in spring and the lowest in summer. In particular, the wind power density in summer is about a half of that in spring. The diurnal variation of the wind power density shows that the highest and lowest densities occur in the afternoon and between 3 and 6 am in local time, respectively. The most potential wind energy generation regions are the Gaema Plateau in the central region, the northeast part of Hamgyeongbuk-do, the south coast of Pyongan-do and the west coast of Hwanghae-do. The mean annual wind power density in Changjin is 151.2 W/m2 , which is equivalent to the class of 3. In Ryongyon, the annual mean wind power density is 102.4 W/m 2 , which belongs to the class of 2.

To examine the wind energy potential of North Korea, climatological wind map was constructed using the 30-year hourly observations of wind speed and direction at 27 meteorological stations. This examination was based on the Weibull model, which represents the probability density distribution of wind speed. It was found that overall, high terrain(Geama Gowon) in the central-northern part and south-west coast (Hwanghae-do) of North Korea have the annual average wind speed which exceeds 4 m/s at 50 m altitude above ground. The wind speed >5 m/s is more persistent in spring, but less in summer. Amongst the meteorological stations, Changjin and Yangdok show the most persistent wind speed in time and strength.

An advection-diffusion equation for a ground-level finite area source is solved analytically in a closed form using the superposition method. Power laws are assumed for height-dependent wind speed and vertical eddy diffusivity and for the downwind distance-dependent standard deviation of concentration distribution in the lateral direction. Results of the analysis show that the ground-level concentration increases with increasing downwind distance inside the source region and then decreases rapidly beyond the downwind edge of the source region. The ground-level concentration inside the source region is sensitive to exponents in the power laws for wind speed and vertical eddy diffusivity, while the ground-level concentration outside the source region is sensitive to the standard deviation of concentration distribution in the lateral direction. The solution for the ground-level finite area source is compared with solutions for a laterally infinite area source and a point source. The ratio of the ground-level concentration for the finite area source to that for the laterally infinite area source is highly dependent on lateral eddy diffusivity but almost independent of exponents in the power laws for wind speed and vertical eddy diffusivity. This is also true for the ratio of the ground-level concentration for the finite area source to that for the point source.

Local advection of scalar quantities such as heat, moisture, or carbon dioxide occurs not only above inhomogeneous surfaces but also within roughness elements on these surfaces. A two-dimensional advection–diffusion equation is applied to examine the fractionation of scalar exchange into horizontal advection within a canopy and vertical turbulent eddy transport at the canopy top. Simulations were executed with combinations of various wind speeds, eddy diffusivities, canopy heights, and source strengths. The results show that the vertical turbulent fluxes at the canopy top increase along the fetch and approach a limit at some downstream distance. The horizontal advection in the canopy is maximum at the edge of canopy and decreases exponentially along the fetch. All cases have the same features, except the absolute quantities depend on the environmental conditions. When the horizontal axis is normalized by using the dimensionless variable xK/uh2, horizontal diffusion is negligible, and the upwind concentration profile is constant, the curves of horizontal advection and vertical flux collapse into single, unique lines, respectively (x is the horizontal distance from the canopy edge, K is the eddy diffusivity, u is the wind speed, and h is the canopy height). The ratios of horizontal advection to the vertical turbulent flux also collapse into one universal curve when plotted against the dimensionless variable xK/uh2, irrespective of source strength. The ratio R shows a power-law relation to the dimensionless distance [R = a(xK/uh2)−b, where a and b are constant].

Pumps are used widely in industrial plants, energy systems, ships, etc. Generally, they consume nearly 20% of the each nation's total electrical energy. During pump's operation, energy loss can be huge if its efficiency is low. Usually, the pump should be repaired or replaced if it cannot operate at high enough efficiency. By measuring pump efficiency, the loss can be estimated. Currently, there are two methods to measure pump efficiency, the thermodynamic method and traditional technique. Each one has its advantages and disadvantages. The features of these two methods and the comparison between them are introduced in this paper. Pump efficiency instrumentation (PEI) is a device which was made to analyze these two methods. PEI continuously monitors parameters at real-time and saves all information in special file type. The information collected from PEI is advantageous for the management of pump's electrical energy; hence proper maintenance plan can be conveniently given in advance.

Electrical characteristics of Pt/Ti/Pt/Au and Pd/Zn/Pd/Au contacts to p-type InGaAs grown on an InP substrate have been characterized as a function of the doping concentration and the annealing temperature. The Pt/Ti/Pt/Au contacts produced the specific contact resistance as low as , when heat-treated at an annealing temperature of . Comparison of the Pt/Ti/Pt/Au and Ti/Pt/Au contacts showed that the first Pt layer plays an important role in reducing the contact resistivity probably by lowering energy barrier at the metal-semiconductor interface. For the Pd/Zn/Pd/Au contacts, the contact resistivity remained virtually unchanged with increasing annealing temperature. The specific contact resistivity as low as was obtained. The results indicate that the Pt/Ti/Pt/Au and Pd/Zn/Pd/Au schemes could be potentially important for the fabrication of InP-based optoelectronic devices, such as photodetector and optical modulator.