• Journal of Applied Reliability
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• 제5권2호
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• pp.273-287
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• 2005

Accelerated life test models and procedure are developed to assess the reliability of Refrigerator door switch. The main function of door switch is to operate bulb lamp and fan motor in the refrigerating room. The accelerated life test method and test equipments are developed using the relationship between stresses and life characteristics of the products. Using the developed accelerated life test method, the parameters of the ALT model and life time distribution are estimated and the reliability of the Door S/W at use condition if assessed. The proposed accelerated life test method and procedure may be extended and applied to testing similar kinds of products to reduce test time and costs of the tests remarkably.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제31권6호
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• pp.17-22
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• 2003

An airship is statically unstable, because it has no wing, relatively small tails and a large hull. Hence, an accurate prediction of dynamic stability is critical. In this study, dynamic stability data of the 50m Length Airship were acquired through forced oscillation wind tunnel tests. The tests were done in Birhle Applied Research Inc's Lange Amplitude Multi-Purpose(BAR LAMP) Facility located in Germany. The tests were composed with 16 static runs and 26 dynamic runs. As results, it is obtained that dynamic characteristics of the airship depend on the sideslip angle, the angular rate and its direction as well as the angle of attack. Generally, three directional moments have damping, but the normal force, the side force, and the cross-derivatives are unstable. The dynamic derivatives are not sensitive to the control surfaces, but nonlinear to the sideslip angle.

• Korean Journal of Veterinary Research
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• 제51권1호
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• pp.15-20
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• 2011

In this study, we isolated 12 of Brucella (B.) spp. from cattle, which have been positive in Rose Bangal test and tube agglutination test in Gyeongbuk province in 2009. According to AMOS PCR analysis, isolated 12 strains were identified as B. abortus. Murine derived macrophage, RAW 264.7 cells, were infected with isolated 12 strains or reference strain (B. abortus 544), and bacterial internalization were characterized. According to these results, we divided the isolated strains into the following three groups: class I, lower internalization than that of B. abortus 544; class II, similar internalization to that of that of B. abortus 544; class III, higher internalization than that of B. abortus 544 within RAW 264.7 cells. Furthermore, intracellular growth, bacterial adherent assay, LAMP-1 colocalization, virulence in mice and surface protein pattern were characterized. From these results, representative strains of class III showed lower LAMP-1 colocalization, higher adherent efficiency, higher virulence in mice than those of B. abortus 544, and showed different pattern of surface proteins. These results suggest that B. abortus field strains, isolated from cattle in Korea, possess various virulence properties and higher internalization ability of field strain may have an important role for its virulence expression.

• Journal of Korean Ophthalmic Optics Society
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• 제12권3호
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• pp.7-17
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• 2007

There has been an increase in rigid gas permeable contact lens prescription by the optometrists in Korea since 1995. Therefore, the aim of our study was to find out which equipment is needed for adequate RGP contact lens prescription and the level of the clinical knowledge that they have and the level of education for the patient, to seize about the extended lens education programmes for the Korean optometrist. Also, we tried to figure out the problem that they had in the RGP contact lens prescription, to develope the educational programs for students and to improve legal uncertainties, through this research. The result came out with the following through questionnaires of 400 male and female opticians who is in clinical field. The distributions of respondents are 270 male (67.5%), 130 female (32.5%), and 356 optometry major (89%). We found out the optometry-majored people had faster clinical lens prescriptions (p=0.000), 72.5% of opticians prescribe the RGP-Lenses, and 27.5% do not because of laking in experience (P=0.000). They responded that they need slit-lamp, button lamp, fluorescein dry paper, and etc,for prescription or fitting test. In regular-check-up (Follow-up), the result came out very low by 83% of respondents who are not getting it regularly. And 83.5% (334 people) of them wanted to have those Extended Educational Programs and also the Clinical Education Programs.

• Journal of Bio-Environment Control
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• 제29권2호
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• pp.105-109
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• 2020

This study was conducted to the improvement of solar light-based artificial light supply system and effect of lettuce cultivation. The artificial light supply system was consisted of units such as light source, power, system measurement and controller. The light source supply was composed of a solar transmitter and an LED lamp. The power supply consisted of an leakage breaker, SMPS, LED controller and relay. The solar transmitter was made of a quartz optical fiber with optimal light transmission. Artificial light used white lamp among LEDs. System measurement and control consisted of touch screen, Zigbee communication module and light quantity sensor. The results of test confirmed that the LED light is automatically activated when the intensity measured by the light intensity sensor is 200 μmolm^-2s^-1 or less. Moreover, the leaf length, root length, chlorophyll content and root fresh weight of optical fiber treatment was hight than LED lamp treatment. Therefore, it can be inferred that the energy-saving solar light collector device can be effective in the indoor lettuce production. However, the use of LED lamp is also recommended to assure the availability of sufficient sunlight in cloudy and rainy days.

• Journal of the Korean Chemical Society
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• 제54권2호
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• pp.215-221
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• 2010

Salmonella is an important food-and water-borne pathogen associated with acute gastrointestinal illnesses around the world. The most common serotypes isolated from humans are Salmonella enterica serotype Typhimurium (S. Typhimurium) and S. Enteritidis. Traditional detection methods for Salmonella are based on cultures using selective media and characterization of suspicious colonies by biochemical and serological tests. These methods are generally time-consuming and not so highly sensitive. Recently, the Loop Mediated Isothermal Amplification and real-time PCR has been used as a highly sensitive, specific, and rapid test for the presence of pathogenic bacteria. In this study, a LAMP and real-time PCR was used to detect S. Typhimurium and S. Enteritidis. We selected target genes, which were the in invA and a randomly cloned sequence specific for the genus Salmonella. With LAMP and real-time PCR, random sequence was detected from Salmonella spp, invA were detected from all strain of S. Typhimurium and S. Enteritidis. This assay indicate that the specificity, sensitivity and rapid of the LAMP and real-time PCR make them potentially valuable tools for detection of S. Typhimurium and S. Enteritidis.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제17권6호
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• pp.199-206
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• 2016

The aim of this study was to establish the optimal conditions to design a shoe rack that could effectively sterilize and deodorize shoes contaminated by various bacteria. The manufacture and evaluation of a shoe rock was conducted for one year from October 2014 to September 2015. The antibacterial efficacies were evaluated using Escherichia coli and Staphylococcus aureus by JIS Z 2801:2010. The deodorization efficiency was identified by the standard method for deodorization efficiency evaluation of an indoor air cleaner established by Korea Air Cleaning Association, SPS-KACA002-132:2006. The results showed that antibacterial evaluation showed more than 99.9% of the sterilization effects on Escherichia coli and Staphylococcus aureus after exposure to ultraviolet (UV) light for 30 seconds. The average deodorization efficiency for the test gases was 42.5%. The temperature in the shoes and in the shoe rack was lower than $40^{\circ}C$ and $25^{\circ}C$, respectively, when the UV lamp was turned on for 5 minutes and off for 25 minutes repeatedly. This was controlled by turning the UV lamp on and off to maintain the appropriate temperature in the shoes. In conclusion, the real deodorization efficiency is expected to be higher than the measured value because the internal volume of the shoe rack was smaller than the test chamber used to measure the deodorization efficiency. The deodorization effect could be increased further by the sterilization of bacteria causing bad odors in shoes. Further studies will be needed to determine the temperature deviations within the shoe rack to provide constant conditions.

• Journal of the Korean Recycled Construction Resources Institute
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• 제8권3호
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• pp.356-364
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• 2020

An experimental study to investigate the effect of self-cleaning of mortar mixed with photocatalyst was performed out in this study. Test parameters included the photocatalyst content and surface roughness of the specimens. The experimental mortar specimens were manufactured by mixing a photocatalyst by cement weight of 2.5%, 5.0%, 7.5% and 10.0%. In addition, the surface roughness was categorized into three cases. They included flat surface condition, little surface roughness(medium roughness), and high surface roughness. After mortar specimens were cured for 28 days, they were illuminated by an ultraviolet lamp for 24 hours and immersed in a methylene blue conditioning solution for 12 hours. Thereafter, an ultraviolet(UV) lamp was illuminated on the specimens for 48 hours in an experimental chamber and then the color change of methylene blue solution was measured by using a spectrophotometer over illuminating time of UV lamp. The color change of methylene blue tended to increase as photocatalyst contents increased. Test results meant that photocatalyst was effective for self-cleaning in mortar. However, the color change of the methylene blue solution did not show a noticeable tendency at different surface roughness conditions. It might be due to the uneven photocatalyst distribution on the surface of mortar specimens.

• Journal of Applied Reliability
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• 제14권3호
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• pp.176-181
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• 2014

In these days, new and renewable energy is getting popular around globe and wind power generator is one of the renewable energy. In this study, we conducted a study on defect detection of composite material blade for wind power generator by applying active infrared thermography and produced a defect test piece by applying composite material used for blade of wind power generator. An infrared thermal camera and 2 kW halogen lamp are used for the purpose of research as equipments. Also, we analyzed temperature characteristic by using infrared thermal camera after checking a heat source on a test piece and found effectiveness of infrared thermography to blade of wind power generator by detecting defects resulting from temperature difference of a test piece, which eventually improve the safety and reliability of the composite material blade.

• Journal of Korean Society for Quality Management
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• 제41권4호
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• pp.659-672
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• 2013

Purpose: The purpose of this study was to estimate life time of halogen lamps and acceleration factors using accelerated life test. Methods: Voltage was selected as an accelerating variable through the technical review about failure mechanism. The test was performed at 14.5V, 15.5V and 16.5 for 4,471 hours. It was assumed that the lifetime of Halogen lamps follow Weibull distribution and the inverse power life-stress relationship models. Results: Mean lifetimes of pin and screw types were 19,477 hours and 6,056 hours, respectively. In addition, acceleration factor of two items are calculated as 4.8 and 2.2 based on 15.5V, respectively. Conclusion: The life-stress relationship, acceleration factor, and MTTF at design condition are estimated by analyzing the accelerated life test data. These results suggest that voltage was very important factor to accelerate life time in the case of halogen lamps and the life time of pin type is three times longer than screw type lamps.