• Nuclear Engineering and Technology
• /
• 제48권3호
• /
• pp.820-830
• /
• 2016

Pipe wall thinning by flow-accelerated corrosion and various types of erosion is a significant and costly damage phenomenon in secondary piping systems of nuclear power plants (NPPs). Most NPPs have management programs to ensure pipe integrity due to wall thinning that includes periodic measurements for pipe wall thicknesses using nondestructive evaluation techniques. Numerous measurements using ultrasonic tests (UTs; one of the nondestructive evaluation technologies) have been performed during scheduled outages in NPPs. Using the thickness measurement data, wall thinning rates of each component are determined conservatively according to several evaluation methods developed by the United States Electric Power Research Institute. However, little is known about the conservativeness or reliability of the evaluation methods because of a lack of understanding of the measurement error. In this study, quantitative models for UT thickness measurement deviations of nuclear pipes and fittings were developed as the first step for establishing an optimized thinning evaluation procedure considering measurement error. In order to understand the characteristics of UT thickness measurement errors of nuclear pipes and fittings, round robin test results, which were obtained by previous researchers under laboratory conditions, were analyzed. Then, based on a large dataset of actual plant data from four NPPs, a quantitative model for UT thickness measurement deviation is proposed for plant conditions.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권12호
• /
• pp.5047-5056
• /
• 2016

Colorectal cancer (CRC) is a major worldwide health problem owing to its high prevalence and mortality rates. Carcinogenesis in the colon is a multistage and multifactorial process. An imbalance between free radical exposure and anti-oxidant defense systems may leads to oxidative stress and attack of macromolecules which can alter signal transduction pathways and gene expression. Consequently, oxidative damage can lead to cellular dysfunction and contribute to pathophysiological processes in a variety of diseases including CRC. One factor tightly associated with CRC is chronic inflammation, which can be present from the earliest stage of tumor onset. Unpolished rice is an attractive chemoprevention in CRC due to their anti-oxidant and anti-inflammatory activities. The aim of this paper is to review evidence linking oxidative stress and inflammation to CRC and to provide essential background information for understanding future research on oxidative stress and inflammation on CRC. Mechanisms of action of unpolished rice in CRC carcinogenesis are also discussed.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권2호
• /
• pp.797-802
• /
• 2014

We screened a small molecular library that was designed and independently synthesized in vitro and found a new drug (MY-03-01) that is active against ovarian cancer. We established that MY-03-01 effectively inhibited SKOV-3 cell survival in a dose-dependent manner, based on cell viability rates, and that it not only induced SKOV-3 apoptosis by itself, but also did so synergistically with paclitaxel. Secondly, when MY-03-01 was applied at $40{\mu}M$, its hemolytic activity was less than 10%, compared with the control, and there was almost no damage to nor mal cells at this concentration. In addition, we used DAPI staining and flow cytometry to show that MY-03-01 could significantly induce apoptosis of SKOV-3 cells. Finally, we found that MY-03-01 likely induced SKOV-3 apoptosis by activating caspase3 and caspase9 through the mitochondrial pathway.

• Ocean and Polar Research
• /
• 제36권2호
• /
• pp.157-163
• /
• 2014

This study analysed the economic feasibility per hectare of grow out phase production of Oyster farming by rising water temperature in Ocean. Elevated Water temperature by climate change had a bad influence for oyster production and economic feasibility. In the case of production units, the total output of oyster decreases from 213,840 to 205,594 units. Using cost-benefit analysis with discounting rates (5.5%), we estimated the net present value (NPV) and benefit cost ratio (BCR) until 2100 years. The model results showed that the NPV without water temperature rise was 1,565,619,893 won and the NPV with water temperature rise was 1,540,493,059 won. Also, BCR estimated that the former was 2.095 better than the latter was 2.077. To summarise, the economic effect per hectare of water temperature rise in ocean did the damage to the economic loss about 25,126,834 won.

• 한국가축번식학회지
• /
• 제17권1호
• /
• pp.1-6
• /
• 1993

This experiment was conducted to determine the effects of gossypol injection spermatogenesis of mice. Gossypol was injected into the stroma of testes(TS) and the doses of gossypol injected were 5, 10 and 15mg per kg of body weights, respectively. The number of sperm and the weight of testes were gradually reduced(P<0.01) from 2 to 4 weeks after gossypol treatment in all groups of mice treated with gossypol, compared with the control group. The rates of malformation(loss of proacrosome, damage of midpiece and breaking of tail) of sperm were significantly(P<0.01) increased at 2 and 3 weeks after the injection of 10 or 15mg of gossypol. However, the weight of testes and the number of normal sperm were gradually increased and the malformation rate of sperm was decreased between 4 and 6 weeks after injection of 5mg of gossypol. The results of this experiment indicated that probably ireeversible suppression of spermatogenesis could be brought about easily and immediately by the single injection of gossypol into TS.

• 동의생리병리학회지
• /
• 제24권3호
• /
• pp.401-409
• /
• 2010

This study was designed to investigate the effects of BojungIkkiTang-Gamybang freeze dried powder (BITG) on proliferauion, protective of cell death induced by chemicals such as paraquat, hydrogen peroxide etc and anti-oxidative effects in C6 glioma cells. In our results, BITC accelerated proliferation rates of C6 cells in vitro. In addition, protective effects on cell death induced by paraquat and hydrogen peroxide. And, BITC did not have effects on SOD and total glutathione activities, but decresed malone dialdehyde activity. In conclusion, these results suggest the possibility of BojungIkkiTang-Gamybang to protect brain cell or neuronal cell from damage induced by oxidative stress. And also suggest that related mechanisms are involved in malone dialdehyde activity.

• 비파괴검사학회지
• /
• 제36권2호
• /
• pp.130-137
• /
• 2016

Non-destructive testing methods for composite materials (e.g., carbon fiber-reinforced and glass fiber-reinforced plastic) have been widely used to detect damage in the overall industry. This study detects defects using optical infrared thermography. The transient heat transport in a solid body is characterized by two dynamic quantities, namely, thermal diffusivity and thermal effusivity. The first quantity describes the speed with thermal energy diffuses through a material, whereas the second one represents a type of thermal inertia. The defect detection rate is increased by utilizing a lock-in method and performing a comparison of the defect detection rates. The comparison is conducted by dividing the irradiation method into reflection and transmission methods and the irradiation time into 50 mHz and 100 mHz. The experimental results show that detecting defects at 50 mHz is easy using the transmission method. This result implies that low-frequency thermal waves penetrate a material deeper than the high-frequency waves.

• 한국주거학회논문집
• /
• 제17권2호
• /
• pp.135-142
• /
• 2006

The purpose of this study is to obtain the fire safety for underground commercial space with analysing fire loads and ventilation factors. It was adopted the investigation method of field survey with commercial uses for more confidential data. The results of this study can be summarized as follows; 1) The ventilation factor shows $0.04{\sim}0.24m^{1/2}$ and it may develop ventilation-controlled fires which have much fire hazard more than fuel-controlled fires. 2) The highest value of fire load is $158.48kg/m^2$ and appeared in footwear shop which has the value $137.35kg/m^2$ for unfixed combustibles and $21.13kg/m^2$ for fixed combustibles. 3) The average value of burning rates which mean the velocity of fire development and the fire damage range is 0.143. Therefore it is desired to decrease the combustibles of compartment and is needed the method of dispersion arrangement of goods and storage to steel cabinet and so on.

• 대한기관식도과학회지
• /
• 제1권1호
• /
• pp.129-135
• /
• 1995

The superiorly based flap tracheostomy(SBFT) has been advocated as an new technique of tracheostomy to manage a wide variety of causes of upper airway obstruction. This technique has particular applicability in patients who require long term tracheostomy such as in bilateral vocal cord paralysis and severe obstructive sleep apnea. SBFT has numerous advantages such as shortening of the gap between the skin and trachea : construction of a self-sustaining tract ; circumferential mucocutaneous junction to reduce infection, granulation tissue, bleeding, and stenosis of the tract : avoidance of the laryngotracheal damage : easy placement of a tracheostomal stent to promote speech, coughing and swallowing. Most of all, this technique can reduces the suprastomal buckling by the support of the superiorly based tracheal flap, and thus prevents the stenosis of suprastomal airway. The disadvantage of SBFT is more time-consuming procedure than the conventional tracheostomy, A retrospective analysis of 8 patients undergoing SBFT between June, 1994 and March, 1995 in Dankook University Hospital was performed to present the surgical technique and com-plication rates. The average duration of follow up was 11 months. The complications were consisted of a wound infection and a sternal granulation. The other complications including wound dehiscence, tracheitis, pneumonia, tracheal granulation, sternal narrowing and subglottic stenosis were not experienced.

• Journal of Welding and Joining
• /
• 제18권5호
• /
• pp.105-111
• /
• 2000

The wear behavior of thermal sprayed AlSiMg-40TiC composite coatings were studied as a function of load and sliding velocity under unlubricated conditions. Experiments were performed using a block-on-ring(WC-6wt%/Co, Hv 1500) type. The tests were carried out a various load(30∼ 125.5N) and sliding velocity(0.5∼2.0m/s). Three wear rate regions were observed in the AlSiMg-40TiC composite coatings. The wear rate in region I at low load (less then 8N( were less than 1×{TEX}$10^{-5}${/TEX}㎣/m. Low wear rates in region I resulted from the load-bearing capacity of TiC particles. The transition from region I to II occurred when the applied load exceeded the fracture and pull-out strength of the particles. The TiC fractured particles trapped between the specimen and the counterface acted as third-body abrasive wear. The subsurface layer worn surface in region II was composed of the mechanically mixed layer (MML). The wear rate increase abruptly above a critical load (region III). The high wear rate in region III was induced by frictional temperature and involves massive surface damage.