• 열처리공학회지
• /
• 제18권3호
• /
• pp.164-171
• /
• 2005

Iodine-Induced Stress Corrosion Cracking (ISCC) properties of Zircaloy-4 and HANA4 developed in KAERI for the high burn-up nuclear fuel cladding were evaluated. To confirm the effect of final heat treatment on ISCC resistance of Zr-alloy, stress relieved and recrystallized specimens were prepared and tested. With the pre-cracked specimen at internal surface, ISCC crack propagation rates and threshold stress intensity factor ($K_{ISCC}$) based on the fracture mechanics were measured by internal pressurization test at $350^{\circ}C$ in iodine environment. $K_{ISCC}$ of Zircaloy-4 and HANA4 cladding were $3.3MPa{\cdot}m^{1/2}$ and $4.4MPa{\cdot}m^{1/2}$, respectively. Pitting corrosion at the crack surface was observed and it seemed that TG crack propagation was derived from the pitting.

• 한국응급구조학회지
• /
• 제22권2호
• /
• pp.23-33
• /
• 2018

Purpose: To investigate the perception of paramedic students about core competence and methods of disaster response. Methods: A self-reported questionnaire was completed by 210 paramedic students in Jeollado from March 2 to April 2, 2018. It comprised 57 questions on topics such as general characteristics (6), related experience (11), cognition of core competence (15), and knowledge of disaster response methods (25). Data were analyzed by means of a frequency analysis, a t-test, an ANOVA, and the Pearson's correlation coefficient using SPSS WIN 21.0. Results: The average score of the participants on disaster response core competence was 3.21. The statement "In case of a disaster, I know the duties of medical staff" scored the second highest, at 3.58, and "In the case of disaster, I can conduct the basic treatment" scored the highest ar 3.59. The average score for the disaster response methods was 3.31. Within the section, the statement "I know what I need to do in the case of burn patients" scored 3.59 and "I know what I need to do in the case of a cardiac arrest patient" scored the highest at 3.93. Conclusion: It is necessary to develop a training module considering the diverse types of disasters and a standardized education program for simulation similar to real-life situations.

• 기술사
• /
• 제14권3호
• /
• pp.9-21
• /
• 1981

The rationalization for Tunnel Drifting is based on the high productivity which is achievable due to Continuous work with a Jumbo Drill, resulting in a much higher efficiency them the Conventional method of blasting, mucking and supporting services. Large projects of over 4,000m Tunnel Drifting are condidated to justify the use of a Jumbo Drill with a combination of superior explosives, machinery and techniques. During a Tunnel Drifting test, Gulita, Nabit and slurry made by Nitro Nobel were employed with following results. 1, Conditions: a. Granite Rock with Two free face b. Burden (W), 2m c. Diameter of hole, 42mm d. Depth of hole 3.5m e. Hole pitch 0.6m f. Charged Explosive per hole Gelatin Dynamite 4 pieces (112.5${\times}$4ea)+Guuita 5 pieces(110g${\times}$5ea) g. Simal-taneous Detonation h. After the blasting resultant rock size was Less 40% of the 0.3m Lumps. 2. Calculation results W=q/Wn=100cm‥‥‥Burden in simultaneous blasting 0.865kg(7.7ea)/hole ‥‥‥Amount of charge but hole pitch is 1.5W-2W The estimated cost of using a Jumbo Drill for the Construction of a 3,000,000 bbL sub-surface oil storage would be as follows: This calculation is based on the Jumbo Drill advancing 3.6m per blasting cycle. Unit cost/bbL Excavation $3.13 The attached sheet shows ideal Drilling pattern with Burn Cut & Smooth blasting method. In conclusion, it is my opinion that this method will assure safety and save cost and improve our technical know-how.

• 한국항공우주학회지
• /
• 제37권12호
• /
• pp.1245-1251
• /
• 2009

고온/고압, 장시간 연소조건에서 비삭마에 가까운 삭마 특성을 갖는 초소형 목삽입재 선정을 위한 연구를 수행하였다. 평가 소재로서 C/SiC, CIT, W/$Y_2O_3$를 선정하였으며, 연소시간 20초의 내열성능평가모타로 시험하였다. 시험 결과 W/$Y_2O_3$가 가장 우수하였으나, 균열이 발생하였다. 본 연구를 통하여 각 소재들의 열반응 특성 및 내열 성능을 이해할 수 있었으며, W/$Y_2O_3$의 적용가능성을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 추계학술대회 초록집
• /
• pp.92.1-92.1
• /
• 2011

Anode off-gas of high temperature fuel cells such as MCFC contains a significant amount of combustible components like hydrogen, carbon monoxide and methane according to fuel utilization ratio of the fuel cell stack. Thus, it is important to fully burn anode off-gas and utilize the generated heat in order to increase system efficiency and reduce emissions as well. In the present study, 25 kW catalytic combustor has been developed for the application to a load-following 300kW MCFC system. Mixing and combustion characteristics have been experimentally investigated with the catalytic combustor. Since the performance of catalytic combustor directly depends on the combustion catalyst, this study has been focused on the experimental investigation on the combustion characteristics of multiple catalysts having different structures and compositions. Results show that the exhaust emissions are highly dependent on the catalyst loading and the ratio of catalytic components. Test results at load-following conditions are also shown in the present study.

• 한국산업융합학회 논문집
• /
• 제18권4호
• /
• pp.207-215
• /
• 2015

Since the oil shock of 1970's there was a strong upward tendency for the use of the high viscosity and poorer quality fuels. Therefore the misfiring engine occurs due to the decrease of quantity injected for lean burn and emission control in CI diesel engine. In this study, it is designed and used the test bed which is installed with turbocharger and intercooler. In addition to equipped using CRDI by controlling injection timing with mapping modulator, it has been tested and analyzed the engine performance, combustion characteristics, and emission as operating parameters.

• 한국분무공학회지
• /
• 제18권1호
• /
• pp.27-34
• /
• 2013

A preburner is one of the key components for a staged combustion cycle engine fueled by kerosene and Lox. Since it has oxygen rich combustion inside, temperature control is very crucial. The temperature of the exhaust gas should be low enough not to burn turbine blade and yet high to keep the efficiency high. In addition temporal and spatial deviations also managed strictly. Conventionally, the required average and maximum temperature are determined by engine system and the preburner should be developed to meet the criteria. Currently being developed preburner has 50K spatial temperature deviation requirement. It was estimated by numerical simulations and proven by tests. The numerical analysis were done with both supercritical condition and normal conditions. The tests results showed that the temperature deviations were less than expected, and the results from the test and simulations were well agreed when the supercritical conditions were considered. Above all, since the gas temperature created by the preburner is very stable with minimum deviation, the preburner developed can be used to drive a turbine and for gas-liquid combustion chambers.

• 지역사회간호학회지
• /
• 제18권4호
• /
• pp.643-650
• /
• 2007

Purpose: This study was to obtain information regarding to agricultural accidents in farm workers in the Kyungpook area. Methods: A questionnaire survey was carried out for 528 workers from the 1st to 31st of March, 2007. Frequency, percentage, mean and chi-square test with the SPSS program were used to analyze the data. Results: The causes of agricultural accidents include falling(29.0%), overseeing(18.9%), traffic accident(17.4%), putting between machinery(11.7%), crashing(5.3%), fire (0.6%) in the order of frequency. Injuries from agricultural accidents include fracture(44.7%) cerebral bleeding (10.4%), amputation(7.0%), airway obstruction (2.3%) burn(1.9%), drug addiction(1.9%) in the order of frequency. The largest proportion of the subjects of hospital treatment were in their 50s and belonged to the group of high-level economic state. Agricultural machinery collision was the most frequent cause among the subjects of hospital treatment. Conclusion: These results suggest that carelessness can be a potential risk factor for agricultural accidents in farm workers. These findings may give useful information for developing agricultural accident prevention programs for farm workers.

• Carbon letters
• /
• 제9권3호
• /
• pp.200-202
• /
• 2008

In order to improve the thermal stability of PAN-based electrospun fibers, AP-PER-MEL and $TiO_2$ were added in to the fibers as additives. The polymer composite with uniformly mixed additional agents was obtained. In case of non-treated sample, the fibers were burn off completely with high rate within $620^{\circ}C$. But in case of treated samples (EF-M and EF-MT), it is sure that the thermal stability was improved by studying TGA data and ISO flammability test about 20 and 30%, respectively. A synergy effect of adding two kinds of agents (AP-PER-MEL and $TiO_2$) into PAN-based electrospun fibers was confirmed. Through SEM images, it is confirmed that the fiber shape can be kept even after addition of agents (AP-PER-MEL and $TiO_2$). Finally the thermal stability of fibers was largely developed with keeping the nature of PAN-based fibers effectively.

• Journal of Pharmaceutical Investigation
• /
• 제27권2호
• /
• pp.139-143
• /
• 1997

Epidermal growth factor (EGF) is a mitogen which activate the proliferation of basal cells in skin, which implicate the wound healing in severe skin damage such as burn. To carry out the preclinical test for the pharmacological action of EGF, EGF in transdermal delivery system must be stable. Since EGF is a protein susceptible to proteolysis and unstable in aqueous solution, in vitro stabilization of EGF is prerequisite for the formulation. In this study, effect of additives on the stability of EGF is investigated in vitro. The stability of EGF in aqueous solution was enhanced with the various water-soluble polysaccharides such as HPMC, sorbitol, mannitol and dextrin. EGF was successfully extracted from the ointment with 5% HPMC solution, and EGF in aqueous solution and ointment was also successfully stabilized with 5% HPMC. The ointments prepared with different amount of EGF were applied on the damaged dorsal skin of rats for the determination of optimal concentration of EGF. The ointment with EGF $(10\;{\mu}g/g)$ showed good wound healing action on the damaged skin of rats.