• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.6
• /
• pp.723-730
• /
• 2013

The speed-limit regulation on a turnout is the main factor inhibiting the speed-up of conventional lines. The specified speed for a train moving through a turnout system is lower than that for a train traveling over the general track. This is done to ensure the running safety of a railway vehicle moving through a turnout. In this study, the shape change example of the guard rail component of a turnout in the Daegu Metropolitan Transit Corporation (DTRO) system was studied. A theoretical examination of the geometrical interaction formula according to wheel/rail shape at the turnout was conducted. Running safety analysis by changing the length of the guard rail on the F10/F12 turnout using the developed analysis techniques (by VI-Rail) was achieved, and the effect on railway safety was examined accordingly.

• Journal of the Korean Society of Safety
• /
• v.27 no.3
• /
• pp.131-140
• /
• 2012

Though there might exist not a few differences between cyclic works and atypical works, many researchers have applied the same assessment techniques that used for repetitive works, which may result introduce bias in their conclusions. This research aimed to verify whether there exist non-negligible work characteristics and/or dissimilarity among works with different work nature and whether one of the most prevalent assessment techniques for assessing ergonomic hazards of musculoskeletal disorders, REBA, can be applied to atypical works. For a general hospital, an automobile repair shop, and two auto-part assembly plants which manufactures quite different parts, a questionnaire survey and field investigation and ergonomic assessment were carried out and analyzed statistically with reference to the 3rd Quantification technique. The results showed that there exist remarkable difference between physical factors in cyclic works and atypical non-cyclic works. As for repetitive work, body posture was significant factors affecting on musculoskeletal disorders while atypical works seemed to have none which implied that the necessity of taking psychosocial factors into account for assessment of hazards. Complain rate in repetitive works was highest shoulder, back, and neck or wrist in sequence. However, there existed no consistent trend in complain rate in atypical works. And, though weight of manufacturing objects was a common factor that can partly explain musculoskeletal complain, time duration was significant in atypical work whereas repeatability and body posture were significant in repetitive works. As being the results, to summarize, it could be said that application of conventional ergonomic assessment techniques regardless of repetitiveness would be fruitless, and that the necessity of a unique methodology focused on atypical non-cyclic works should not be neglected.

• Journal of Korean society of Dental Hygiene
• /
• v.16 no.6
• /
• pp.1033-1045
• /
• 2016

Objectives: This research was conducted to recognize dental health care employees' awareness of patient safety culture and to examine the association between awareness of patient safety culture and patient safety activities. Methods: The subject of this research includes the dental health care employees from 11 different dental hospitals in the nation, dental offices in the 6 different general hospitals in Seoul, and 4 different private dental offices in 2014. A self-reported questionnaire was completed by 485 dental health care employees from March 17 to April 3, 2014. Multiple regression models were used in the analysis. Results: First, the dental health employees' awareness of patient safety culture was 3.25 on average. The extent of patient safety activities was 2.75. The behavior of the supervisor/manager and the adequate explanation showed positive correlation with r=0.213 (p<0.001). The process of communication and the preventative inspection of the medical equipment showed negative correlation with r=-0.258 (p<0.001), and especially the awareness of patient safety culture and the infection control exercise showed the most significant correlation (r=0.293, p<0.001). Second, hospital environment factor of patient safety perceptions positively were related to most of patient safety management activities after controlling several covariates. Conclusions: The result of this research showed that most of the patient safety culture perceptions positively were correlated with patient safety activities. We also found that proper hospital environment, simple communication process, and positive perceptions for patient safety level were more likely to perform patient safety management activities after controlling several covariates. Improving the patient safety perceptions of dental hospital workers is an important consideration.

• Journal of Hydrogen and New Energy
• /
• v.34 no.2
• /
• pp.162-168
• /
• 2023

The fast refueling process of compressed hydrogen has an important impact on the filling efficiency and safety. With the development and use of hydrogen energy, the demand for precision measurement of filling hydrogen thermodynamic parameters is also increasing. In this paper, the compressibility factor calculation model of high-pressure hydrogen gas was studied, and the basic equation of state and thermo-physical parameters were calculated. The hydrogen density data provided by the National Institute of Standards and Technology was compared with the calculation results of each model. Results show that at a pressure of 0.1-100 MPa and a temperature of 233-363 K, the calculation accuracy of the Zheng-Li equation of state was less than 0.5%. In the range of 0.1-70 MPa, the accuracy of Redich-Kwong equation is less than 3%. The hydrogen pressure more influences on the compressibility factor than the hydrogen temperature does. Using the Zheng-Li equation of state to calculate the compressibility factor of on-board high pressure hydrogen can obtain high accuracy.

• Archives of Pharmacal Research
• /
• v.17 no.4
• /
• pp.226-230
• /
• 1994

The characteristics of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release as factors controlling neural activities in the hypothalamus which is an important regulatory site for cardiovascular function wre studied. Two groups of animals : male spontaneously hyperterisive rat (SHR) and age-matched nomotensive wistar rat (NW) were used in this study. Animals at 4, 6 and 16 weeks of age were sacrificed by decapitiation and the hypothalamus was dissected out. Voltage-dependent calcium uptake and norepinephrine release were determined from hypothalamic synaptosomes either in low potassium (5 mM) or high potassium (41 mM) stimulatory conditions by using ^{45}Ca$ isotope and HPLC-ECD techniques. Degrees of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release evoked by calcium uptake in the hypothalamus of prehypertensive phase (4 weeks old) of SHR were significantly smaller than those in NW of the same age. However, in the developmental phase (6 weeks old) and the established phase (16 weeks old) of hyperrtension in SHR, degrees of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release were similar to those of age-matched normotensive wistae eats. These data imply that the deficit in hypothalamic norepinephrine release might be an important underlying factor for the development of hypertension in SHR.

• Korean journal of food and cookery science
• /
• v.27 no.6
• /
• pp.643-651
• /
• 2011

The purpose of this study was to investigate the perceptions, intake levels and information needs of elementary school students on artificial food colorants in order to provide better understanding and proper dietary education to these students. From May to June 2010, a survey was conducted from 315 elementary school students at fifth and sixth grade level who were living in Seoul. The questionnaire was distributed by 14 elementary school teachers to their classroom students. The results showed that food safety was regarded as the most important factor in purchasing food items, and artificial food colorants were the most interested among various food additives. Although there was a lack of general knowledge and the students' estimated intake levels of artificial food colorants from processed foods were comparatively low, most (82.7%) believed that artificial food colorants were dangerous for health. The information they wanted to know most was the safety, necessity, and function of artificial food colorants, in order. Above results suggested the necessity of providing accurate information on artificial food colorants to elementary school students possibly by developing educational materials which can improve the perceptions on artificial food colorants and encourage a safe dietary life.

• Journal of the Korean Society of Safety
• /
• v.28 no.6
• /
• pp.11-16
• /
• 2013

This paper presents a study on the analyzing reliability of smoke fire detector using accelerated life test. In general, the smoke fire detector is broken by dust which flow in smoke detection chamber. In order to conduct accelerated life test of smoke fire detector dust is set accelerated factor in this paper. The dust is fly-ash which is test particle 5th regulated by KS A 0090. The dust accelerated level is 60 g, 180 g and 360 g and failure time is measured by smoke sensitivity testing. It is considered to failure of detector if detector don't operate within 30 secconds when subjected to an air stream having a velocity of 20 cm/s~40 cm/s containing smoke with a concentration of 15% of rate of light-response of 1 m. The goodness of fit test and mean life prediction conduct using the failure time. The result show that life distribution fits the weibull distribution for failure time data and the mean lifes calculate 22.5 year in domestic product and 14.7 years in overseas product applied dust stress only.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.21 no.3
• /
• pp.162-167
• /
• 2011

To identify the relationship between types of job classification (typical and atypical) and the levels of recognition of noise and the hearing threshold shift, a total of 457 workers in a cosmetic company were studied utilizing a questionnaire and the audiometric hearing test. The results were analyzed by factor analysis, t-test, and general linear model, as appropriate. The results showed that atypical workers had higher level of noise recognition but had lower levels of hearing ability, noise exposure, and the knowledge on hearing loss prevention, compared with those of typical workers. The high noise level group of typical workers showed higher threshold shift levels than that of atypical workers. Significant differences were found at 4 kHz for both ears and in right ear only for hearing threshold shift after adjusting age.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.3
• /
• pp.74-80
• /
• 2005

Steel plates used for common structures are manufactured by rolling processes in general. The rolling direction traces generated during the processes have significant influences on mechanical properties and fatigue behavior of the plates. The objective of present study is to investigate those directional characteristics for the enhancement of steel structure safety. SS400 steel plates of 3 mm thickness are tested in this study, When the angles between the tensile loading direction and the rolling direction of the plates are increased, their yield strengths are increased and elongations are rather decreased. It is also shown that fatigue crack growth rates in the plates can be increased according to the changes of those mechanical characteristics. For the safety of the structures, therefore, it is critical to decrease the angles between the rolling direction and the tensile loading direction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.10
• /
• pp.81-89
• /
• 2009

Recently, Guard lamp was divided from electric facilities for general use as dangerous zone of safety management. This paper presents a remote inspection system of guard lamp that can monitor electrical safety factor. Especially, the developed system adopts the measurement algorithm for detecting resistive leakage current($I_{gr}$) flowing based on the phase difference checkable for sensing at a monitor. Also, It was fabricated the repeater for data transmission and the MMI program At this system, we made experiment on stability of resistive leakage current to verify phase comparison detecting algorism.