• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.8
• /
• pp.64-70
• /
• 2007

The electrical accident results from an insulation blackdown by over-voltage, an overheating by the excess of allowable current, a deterioration performance by the passage of time, and so on. This paper discusses how to improve the power control system of PCB in water purifier. The protecting device of present power supply control system in water purifier is composed of the varistor device which acts only for impulse-type surges. So the present system can not be protected others except the surge of impulse-type. The newly-suggested power control system in this paper is designed to protect the system by disconnecting power supply through SSR(Solid State Relay) if the value of input voltage is exceeded the setting value.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.2
• /
• pp.211-216
• /
• 2014

Using a high-rise building water piping after hydrostatic test of the reliability of the leak to be completed if the pressure is maintained until the leak is not commercially available considered. Due to the nature of high-rise buildings and the construction period will take several years from the lower levels of use of the water supply and fire fighting water pipe construction is in progress, the order of which I do most of the first pipe to the construction and more than three years. So kind of riser pipe is complete, install the valve in the basement by installing an automatic pump to maintain a constant pressure after hydrostatic test and after each floor plumbing piping is complete, the progress of the hydrostatic test without undergoing a separate branch pipe the valve is opened automatically when the number of the pressing pressure of the structure. I kind of do and keep working pressure of pipe until the completion of the construction work to keep the damage to human error when it is intended to prepare. In winter, the frost protection and an alternative to drainage water pipe is damaged or deformed, even if unaware of the finishing work to the building, the use of the damage caused by a leak in a after construction of finish work to be expected. Alternative to reduce this damage if the pressure test without fear of freezing to help maintain long-term commercial pressures may be considered.

• Journal of the Korean Society of Safety
• /
• v.19 no.3 s.67
• /
• pp.57-64
• /
• 2004

This is the study for the removal of a toxic heavy metal ions and the recycling of expanded polystyrene wastes. Thus expanded polystyrene wastes collected from the packing materials of TV or chemicals and dissolved by $80wt.\%$ solvent(N, N-Dimethylacrylamide), electrospun in DC 20kV by power supply. Generally, the electrospinning is a process of manufacture to the fibers of nanosize from polymer solution. Manufactured nanofiber mats by electrospinning were sulfonated by cone.-sulphuric acid with $Ag_2S_O_4$ catalysts for the exchange capacity of heavy metal ions and the properties of structure with sulfonated time investigated by FESEM(Feild Emission Scaning Electron Microscope). The ion exchange capacity of light metal$(Na^+)$, Cd(II) and Ni(II), and by a nanofiber mats were 1.94[mmo1/g-dry-mat), 1.72(mmol/g-dry-mat), 1.24(mmol/g-dry-mat), respectively., and water uptake content showed a similar trend with IEC. and The selectivity coefficients $K^M_H$ of Cd(II), Ni((II) ions showed 0.324, 0.228. respectively.

• Proceedings of the Korean Society for Rock Mechanics Conference
• /
• 2008.10a
• /
• pp.33-41
• /
• 2008

The longest tunnel has been halted at Daekwanryung by the failure of the host country of the Winter Olympiad in 2014, but modern High-Power TBM will come to Korea to excavate these long tunnels to establish the better horizontal connection between the western and eastern countries to improve the strong powerful logistic strategy of Korean peninsula. Train operation provides a key function of air movements in a long underground tunnel, and heat generation from transit vehicles may account of the most heat release to the ventilation and emergency systems. This paper indicates the optimal fire suppress services and safety provision for the long railway tunnel which is designed twin tunnel with length 22km in Gangwon province of Korea. The design of the fire-fighting systems and emergency were prepared by the operation of the famous long-railway tunnels as well as the severe lessons from the real fires in domestic and overseas experiences. Designers should concentrate the optimal solution for passenger's safety at the emergency state when tunnel fires, train crush accidents, derailment, and etc. The optimal fire-extinguishing facilities for long railway tunnels are presented for better safety of the comfortable operation in this hard rock tunnel of eastern mountains side of Korea. Since year 1900, hard rock tunnel construction has been launched for railway tunnels in Korea, tunnels have been built for various purposes not only for infrastructure tunnels including roadway, railway, subway, and but also for water and power supply, for deposit food, waste, and oils etc. Most favorable railway tunnel system was discussed in details; twin tunnels, distance of cross passage, ventilation systems, for the comfortable train operations in the future.

• Nuclear Engineering and Technology
• /
• v.49 no.5
• /
• pp.979-988
• /
• 2017

The feasibility of cooling in a pressurized heavy water reactor after a large break loss-of-coolant accident has been analyzed using Multidimensional Analysis of Reactor Safety-KINS Standard code during the recirculation phase. Through evaluation of sensitivity of the fuel channel temperature to various effective recirculation flow areas, it is determined that proper cooling of the fuel channels in the broken loop is feasible if the effective flow area remains above approximately 70% of the nominal flow area. When the flow area is reduced by more than approximately 25% of the nominal value, however, incipience of boiling is expected, after which the thermal integrity of the fuel channel can be threatened. In addition, if a dramatic reduction of the recirculation flow occurs, excursions and frequent fluctuations of temperature in the fuel channels are likely to be unavoidable, and thus damage to the fuel channels would be anticipated. To resolve this, emergency coolant supply through the newly installed external injection path can be used as one alternative means of cooling, enabling fuel channel integrity to be maintained and permanently preventing severe accident conditions. Thus, the external injection flow required to guarantee fuel channel coolability has been estimated.

• Journal of the Institute of Convergence Signal Processing
• /
• v.7 no.3
• /
• pp.143-148
• /
• 2006

There are need to manage the water quality to supply an safety to consumer through pipe and reservoir the drinking water that produced in a clean water reservoir. However, a management of water quality and monitoring in reservoir have never been performed. Recently, the government has enforced standards of water quality. However, we have a inferior technology of water quality as compared with one in USA, Japan, Germany, etc. In case of water quality inspection and analysis equipments, sensor technology is very important to improve the water quality inspection and to develop the analysis equipments. In this paper, we analyze a law and a regulation for management of drinking water quality, and propose the measurement standards of drinking water quality in pH, conductivity, residual chloride, turbidity and water temperature. Then, we analyze electrode sensors that interference within pH, conductivity, residual chloride in interference experiment.

• Journal of Korean Society on Water Environment
• /
• v.39 no.2
• /
• pp.153-161
• /
• 2023

The reservoir tank in an apartment is crucial for maintaining the quality of drinking water after it has undergone treatment. Investigating the water quality and potential contaminants in the reservoir tank is essential to ensure the safety of the drinking water. This study examined the water quality and precipitated suspended solids that accumulate at the bottom of the reservoir tanks in four apartments located in Gyeonggi province. As a result of the water quality investigation, turbidity increased proportionally to the distance from the water treatment plant (WTP) to the household. Heavy metals were also detected in the reservoir tank inlet but not in the water supplied from the WTP. The precipitated suspended solids (SS) in the reservoir tank contain high levels of heavy metals and total organic carbon (TOC). The precipitated SS mainly consists of Al, Mn, and Fe, which are expected to be a combination with turbidity-inducing substances. The X-ray diffraction (XRD) analysis revealed the presence of γ-FeO(OH), MnO₂, and β-Fe₂O₃ in the SS. Additionally, F-EEM analysis indicates that the dissolved organic matter in the SS is mainly derived from a natural water source and microorganism activities, including metal-oxidizing bacteria and biofilms that can absorb metal ions. Based on these findings, several countermeasures can be taken to prevent the inflow of SS into the household, including regularly cleaning the reservoir tank, replacing or cleaning old pipes in the water supply system, and implementing monitoring and filtering systems to manage the SS.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.15 no.4
• /
• pp.345-354
• /
• 2009

The review of statements and coastal development characteristics in South Korea were diagnosed by the consultation on the coastal area utilization in Korea. The occupation and the use of public water were dominated by installation of coastal structure and seawater supply and drainage whereas the reclamation areas were predominantly utilized for developing industrial complex, harbor, fishing port and road. The occupation and the use were dominant in western coast, but reclamation was dominant in southern coast of Korea. The number of utilization cases was particularly greater in Jeonnam, Gyeongnam, and Gyeonggi Province including Incheon. The number of the statements reviews increased by more than 200 cases in 2008 compared with 2007, and most of them were the simple statements. The statements related to ocean disposal of dredged sediment, reclamation, dredging sediment, seawater supply and drainage, and marine sand mining were submitted for review. Coastal utilization was especially active in the regions of seawater quality criteria I and II. In particular, special management sea areas designated under the relevant marine regulations were utilized mostly by reclamation for developing harbor, fishing port and coastal structure. Development activities in national parks comprised primarily structure installation and coastal maintenance. In the fisheries resources protection areas, 40% of the total cases accounted for coastal maintenance, 31% for structure installation, and 16% for seawater supply and drainage. In addition, alternative plans for the improvement in policies and system of marine environmental impact assessment were suggested to enhance the function and confidence of the consultation on the coastal area utilization in Korea.

• Journal of the Korea Safety Management & Science
• /
• v.22 no.4
• /
• pp.9-15
• /
• 2020

As of 2018, total yield of lettuce and strawberry amounted to 93,543 tons (representing 1.0 percent) and 183,639 tons (2.0 percent), respectively, among total yields worth 9,185,889 tons in South Korea. Lettuce is affected by a combination of numerous elements such as varieties, cultivation methods and pests during each growth phase (Lee et al., 1999). It is mainly cultivated in spring and fall. Especially due to respiration rate after harvest leading to reduced quality and poor storage, maintaining annual supply is unavailable (Jang et al., 2018). With the distribution of new varieties, forcing culture and indoor insulated facilities for plant cultivation during winter, strawberries are produced every year except for late summer and early fall. Due to active respiration, transpiration, soft flesh and high water content, the fruit is vulnerable to go bad and got rotten compared to other fruits. Furthermore, it is difficult to maintain freshness due to the possibility of softening, discoloration and fungi (Lee et al., 2012). In this regard, developing improved storage and package techniques is needed to ensure maintaining quality and safety even just two to three days after harvest. In order to ensure improved quality and safety of strawberries and lettuce after harvest, the present study applied a modified atmosphere packaging (MAP) technology (Mostofi et. al., 2008). Going forward, it compared the quality and safety of the two products while being stored in a way that put them in an MAP-applied container and a plastic container at room temperature and 4 degree Celsius.

• Applied Microscopy
• /
• v.38 no.2
• /
• pp.81-87
• /
• 2008

Alkaline reduced water (ARW) has been used for drinking widely in several countries of Asia. The safety and clinical effects of ARW has been reported including anti-oxidative effect and intestinal abnormal fermentation. To confirm the effect of ARW on DSS-induced acute inflammatory bowel disease (IBD) mouse model, we observed the length of total large intestine and the histopathological changes after supplying mineral induced-ARW (MARW) for 2 weeks and oral administration of 4% DSS (dextran sulfate sodium). As the result, the length of total large intestine and the disease scores by macro and microscopical access in the ARWsupplied group showed no significant differences compared with those in the control group. This result suggests that the supply of ARW for 2 weeks exerted no effect on amelioration in the DSS-induced acute IBD model. However, in consideration of the effect of ARW on the improvement of intestinal environment and gastrointestinal disease, this result seems that acute IBD animal model is not suitable or the period of ARW supply is not enough to prove the effect of ARW. The ameliorative effect of ARW on the intestinal abnormal fermentation has been confirmed by some researchers, but the precise mechanism also remain unclear. In conclusion, although MARW had no effect on the DSS-induced acute experimental colitis model, further studies on the verification of the effects of ARW by using other intestinal disease model and by long-term supply of ARW will be required. Also, It needs to clear the mechanism of ARW on the intestinal environment.