• Journal of Korean society of Dental Hygiene
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• v.7 no.3
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• pp.213-230
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• 2007

The purpose of this study was to examine the state of infection control provided to members of Korean Dental Hygienists Association. The subjects in this study were dental hygienists who attended a symposium on July 1. 2006. after a survey was conducted, the answer sheets from 489 participants were analyzed, and the findings of the study were as follows: 1. Possession of disinfection room was being(72.7%), and person of infection control was zero(52.9%). Number of sterilizer was one(62.2%). 2. As a repetition choice, type of sterilizer was autoclave(97.9%), UV sterilizer(67.4%) and EO gas sterilizer(21.4%). As a repetition choice, infection materials was ethanol(84.1%). 3. Water tube of unit and chair was using of sterilized water(42.9%). Sterilizing of compressed air was no(69.0%). 4. Re-using of disposal was not using(62.5%), re-using disposal was suction tip(28.2%)(repetition choice) 5. In sterilization of instruments, hand-piece was every using time(28.4%), and reamer-file, bur, mirror, pincette, explorer, hand scaler and ultrasonic scaler were high in every using time. 6. Individual protection was high of using, cleaning of hands before treatment was every treatment(87.0%). Type of soap was liquid type in dental clinic(48.2%), infection soap in dental hospital(41.2%) and solid soap in public health center(50.6%). Answered that they need regular oral health education, and 82.9% respondents answered that they need oral health technicians in school. And 87.8% respondents needed individual oral health education for the benefit of better oral health.

• Nuclear Engineering and Technology
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• v.43 no.3
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• pp.301-308
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• 2011

The diametral creep of pressure tubes (PTs) in CANDU (CANada Deuterium Uranium) reactors is one of the principal aging mechanisms governing the heat transfer and hydraulic degradation of the heat transport system (HTS). PT diametral creep leads to diametral expansion, which affects the thermal hydraulic characteristics of the coolant channels and the critical heat flux (CHF). The CHF is a major parameter determining the critical channel power (CCP), which is used in the trip setpoint calculations of regional overpower protection (ROP) systems. Therefore, it is essential to predict PT diametral creep in CANDU reactors. PT diametral creep is caused mainly by fast neutron irradiation, temperature and applied stress. The objective of this study was to develop a bundle position-wise linear model (BPLM) to predict PT diametral creep employing previously measured PT diameters and HTS operating conditions. The linear model was optimized using a genetic algorithm and was devised based on a bundle position because it is expected that each bundle position in a PT channel has inherent characteristics. The proposed BPLM for predicting PT diametral creep was confirmed using the operating data of the Wolsung nuclear power plant in Korea. The linear model was able to predict PT diametral creep accurately.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1996.04a
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• pp.22-22
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• 1996

;The Kwinana Shoreline Fumigation Experiment(KSFE) took place in Fremantle, WA, Australia between 23 January and 8 February, 1995. All measurement systems performed to expectation. The CSIRO DAR(Division of Atmospheric Research) LIDAR measured plume sections from near the Kwinana Power Station(KPS) stacks to up to about 5 km downstream. It also measured boundary layer aerosols and the structure of the boundary layer on some occasions. Both stages A and C of KPS were used as tracers at different times. Radiosonde and double theodolite sounding systems measured temperature, humidity, air pressure and wind structure at the coast(Woodman Point) and at the inland(ALCOA residue dump) site at intervals of roughly two hours. These were supplemented by mid afternoon soundings(radiosonde and single theodolite) by Department of Environmental Protection(DEP) at Swanbourne. The Flinders aircraft measured wind, turbulence and temperature structure of the atmospheric boundary layer, concentrations of $C0_2,\;0_3,\;S0_2\;and\;NO_x$ in the smoke plumes and surface radiation over both land and sea. CSIRO DCET(Division of Coal and Energy Technology) vehicle successfully interceptde many smoke plumes and using a range of tracers will be able to identify the various sources much of the time. Routine data from the DEP and Kwinana Industrial Council(KIC) air quality monitoring networks were also automatically logged. Murdoch University measured surface heat flux at Hope Valldy monitoring station and also at Wattleup monitoring station for the last five days. The heart of the LIDAR system is a Neodymium-doped Yttrium-aluminumgarnet(Nd:Y AG) laser operating at a fundamental wavelength of 1064 nm, with harmonics fo 532 nm and 355 nm. A small fraction of the laser beam is scattered back to the LIDAR, collected by a telescope and detedted by a photomultiplier tube. The intensity of the signal as a function of time is a measure of the particle concentration as a function of distance along the line of the laser shot. The results of nine days special field observations are summarized in detail.etail.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.437-451
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• 2019

Purpose: The purpose of this study is to improve the quality of the PGM system by improving the structure and production process of slip-ring rotary joint for radar. Methods: The improvement measures for each cause are established through failure analysis of broken items. Specifically, changing in the housing to improve the heating system. Changing the transportation method to prevent damage to equipment during transport. Changing work process of the attenuator ring to prevent damage. etc. Results: The results of this study are as follows; improving the heating system reduces heat generated by the attenuator by about 7 degrees and obtain additional temperature margins. Reduction of defect rate because of adding X-band rotary joint run-out measurement test, ESS of slip-ring rotary joint and Transportation improvement(reinforced flight boxes, tube protection, etc). Getting stable VSWR values by improving work process of attenuator overheating due to a bad bonding process. Conclusion: Through this study, improvements were made to slip-ring rotary joint that failed repeatedly for various reasons. As a result of the application of the improvements, the same fault does not occur until now, so we can see that the quality of PGM has improved.

• Computers and Concrete
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• v.17 no.6
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• pp.787-799
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• 2016

Climate anomalies in recent years, numerous natural disasters caused by landslides and a large amount of entrained sands and stones in Taiwan have created significant disasters and greater difficulties in subsequent reconstruction. How to respond to these problems efficaciously is an important issue. In this study, the sands and stones were doped with recycled materials (waste LCD glass sand, slag powder), and material was mixed for recycled ready-mixed soil. The study is based on security and economic principles, using flowability test to determine the water-binder ratio (W/B=2.4, 2.6, and 2.8), a fixed soil: sand ratio of 6:4 and a soil: sand: glass ratio of 6:2:2 as fine aggregate. Slag (at concentrations of 0%, 20%, and 40%) replaced the cement. The following tests were conducted: flowability, initial setting time, unit weight, drop-weight and compressive strength. The results show that the slump values are 220 -290 mm, the slump flow values are 460 -1030 mm, and the tube flow values are 240-590 mm, all conforming to the objectives of the design. The initial setting times are 945-1695 min. The unit weight deviations are 0.1-0.6%. The three groups of mixtures conform to the specification, being below 7.6 cm in the drop-weight test. In the compressive strength test, the water-binder ratios for 2.4 are optimal ($13.78-17.84kgf/cm^2$). The results show that Recycled ready-mixed soil materials (RRMSM) possesses excellent flowability. The other properties, applied to backfill engineering, can effectively save costs and are conducive to environmental protection.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3854-3859
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• 2023

Background: This study aims to develop an evaluator that can quickly and accurately evaluate the shielding of low-energy industrial radiation generators. Methods: We used PyQt to develop a graphical user interface (GUI)-based program and employed the calculation methodology reported in the National Council on Radiation Protection and Measurements (NCRP)-49 for shielding calculations. We gathered the necessary factors for shielding evaluation using two libraries designed for Python, pandas and NumPy, and processed them into a database. We verified the effectiveness of the proposed program by comparing the results with those from safety reports of six domestic facilities. Results: After verifying the effectiveness of the program using the NCRP-49 example, we obtained an average error rate of 1.73%. When comparing the facility safety report and results obtained using the program, we found that the error rate was between 1.09% and 6.51%. However, facilities that did not use a defined shielding methodology were underestimated by 31.82% compared with the program (the final barrier thickness satisfied the shielding standard). Conclusion: The developed program provides a fast and accurate shielding evaluation that can assist personnel that work in radiation generator facilities and government officials in reviewing safety.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.421-424
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• 2023

This case report presents the case of a 49-year-old man who presented to our level I trauma center after sustaining injuries in an altercation with local law enforcement in which he was shot with a less lethal bean bag and tased. In a primary survey, a penetrating left supraclavicular wound was noted in addition to a taser dart lodged in his flank. No other traumatic findings were noted in a secondary survey. Given hemodynamic stability, completion imaging was obtained, revealing a foreign body in the left lung, a left open clavicle fracture, a C5 tubercle fracture, a possible grade I left vertebral injury, and a left first rib fracture. Soft tissue gas was seen around the left subclavian and axillary arteries, although no definitive arterial injury was identified. The bean bag projectile was embedded in the parenchyma of the left lung on cross-sectional imaging. The patient underwent thoracotomy for removal of the projectile and hemostasis. A thoracotomy was chosen as the operative approach due to concerns about significant bleeding upon foreign body removal. A chest tube was placed and subsequently removed on postoperative day 5. The patient was discharged on postoperative day 7. At a 2-week outpatient follow-up visit, the patient was doing well. This case report is the first to describe this outcome for a drag-stabilized bean bag. Although law enforcement officers utilize bean bag projectiles as a "less lethal" means of crowd control and protection, these ballistics pose significant risk and can result in serious injury.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.893-899
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• 2024

In a secondary cooling system of a sodium-cooled fast reactor (SFR), rapid detection of hydrogen due to sodium-water reaction (SWR) caused by water leakage from a heat exchanger tube of a steam generator (SG) is important in terms of safety and property protection of the SFR. For hydrogen detection, the hydrogen detectors using atomic transmission phenomenon of hydrogen within Ni-membrane were used in Japanese proto-type SFR "Monju". However, during the plant operation, detection signals of water leakage were observed even in the situation without SWR concerning temperature up and down in the cooling system. For this reason, the study of a new hydrogen detector has been carried out to improve stability, accuracy and reliability. In this research, the authors focus on the difference in composition of hydrogen and the difference between the background hydrogen under normal plant operation and the one generated by SWR and theoretically estimate the hydrogen behavior in liquid sodium by using ultra-accelerated quantum chemical molecular dynamics (UA-QCMD). Based on the estimation, dissolved H or NaH, rather than molecular hydrogen (H₂), is the predominant form of the background hydrogen in liquid sodium in terms of energetical stability. On the other hand, it was found that hydrogen molecules produced by the sodium-water reaction can exist stably as a form of a fine bubble concerning some confinement mechanism such as a NaH layer on their surface. At the same time, we observed experimentally that the fine H₂ bubbles exist stably in the liquid sodium, longer than previously expected. This paper describes the comparison between the theoretical estimation and experimental results based on hydrogen form in sodium in the development of the new hydrogen detector in Japan.

• Composites Research
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• v.37 no.2
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• pp.108-114
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• 2024

Due to the continuously increasing global demand for electricity, the demand for high-voltage submarine cables is also increasing. One of the issues that need to be addressed for submarine cables is the high production cost and expensive laying costs. Submarine cables exposed to the marine environment encounter external forces such as wave and current, leading to issues such as cable damage due to external factors or high maintenance costs in the event of an accident. Therefore, we are preparing for the uncertainty of the submarine environment through many protective materials and protective equipment. In this study, we examined the bending performance of piggyback clamps (PBC) and strap, which are representative protective equipment, in response to the submarine environment through analytical methods. To examine the structural performance of PBC, the bending performance were assessed under the maximum bending moment criterion of 15 kN·m for the flexible protection tube. As a result, it was confirmed that the structural performance regarding the bending moment of both PBC and straps was ensured.