• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.5
• /
• pp.3370-3377
• /
• 2015

FMECA(Failure Mode, Effects and Criticality Analysis) techniques to make quantitative evaluation of failure effects severity and criticality have been applied to systematic failure analysis for reliability improvement of train which should provide regular service and secure high level of safety as a mass transportation system. These FMECA techniques do not fully reflect the inherent train operation and maintenance circumstances because they are based on the FMECA standards devised for other industries such as automobile industry and FMECA standard dedicated to train industry has not been established yet. This paper analyzes FMECA standards for various industries, and suggests a FMECA technique dedicated to train industry which makes failure effect analysis and criticality analysis step by step and makes criticality analysis placing emphasis on the severity of the failure effect. The proposed technique is applied to FMECA of high-speed current breaker which is a core safety device of train using field failure data for 15 years of train maintenance. The FMECA results show that breakage of arc chute has the highest risk with 3rd severity class and 5th criticality class among all the components of high-speed circuit breaker. Damage and poor contact of electronic valve, and cylinder breakage with 3rd severity class and 4th criticality class are followed by. These results can be applied to improvement of design and maintenance process for high-speed circuit breaker of train.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.11
• /
• pp.541-549
• /
• 2018

This paper deals with the braking dynamic behavior of diesel electric locomotive pulling domestic cargo and passenger vehicles. Friction coefficient, pneumatic pressure, and running resistance affecting the braking system were tested. For the friction coefficient, the Dynamo test was performed with reference to UIC 541-4. The results are analyzed by multivariate regression and the relationship between braking force and ititial velocity is presented. The pneumatic pressure were classified into service braking and emergency braking. In order to reflect the characteristics of the brake valve and piping, the pressure rising over time was measured in the vehicle. In order to reflect the external force acting on the vehicle, we carried out the test of EN 14067-4 and presented the second order polynomial formula on a running resistance. The running resistance test results were compared with other countries. The dynamic behavior of a diesel electric locomotive running on a straight flat track based on vehicle resources, friction coefficient, braking pressure, and running resistance is simulated using the time integration presented in EN 14531-1. The simulation results were compared and verified with the vehicle braking test results. The results of this study can be used to analyze the dynamic braking behavior of a train. Also, it is expected that various parameters affecting braking in vehicle design can be analyzed and used as basic data for braking performance improvement.

• Analytical Science and Technology
• /
• v.34 no.1
• /
• pp.23-35
• /
• 2021

In order to measure the volatile organic compounds (VOCs) of a sample which is too large to use commercially available chamber, a stainless steel vacuum chamber (VC) (with an internal diameter of 205 mm and a height of 50 mm) was manufactured and the temperature of the chamber was controlled using an oven. After concentrating the volatiles of the sample in the chamber by helium gas, it was made possible to remove residual volatile substances present in the chamber under reduced pressure ((2 ± 1) × 10-2 mmHg). The chamber was connected to a purge & trap (P&T) using a 6 port valve to concentrate the VOCs, which were analyzed by gas chromatography-mass spectrometry (GC-MS) after thermal desorption (VC-P&T-GC-MS). Using toluene, the toluene recovery rate of this device was 85 ± 2 %, reproducibility was 5 ± 2 %, and the detection limit was 0.01 ng L-1. The method of removing VOCs remaining in the chamber with helium and the method of removing those with reduced pressure was compared using Korean drinking water regulation (KDWR) VOC Mix A (5 μL of 100 ㎍ mL-1) and butylated hydroxytoluene (BHT, 2 μL of 500 ㎍ mL-1). In case of using helium, which requires a large amount of gas and time, reduced pressure ((2 ± 1) × 10-2 mmHg) only during the GC-MS running time, could remove VOCs and BHT to less than 0.1 % of the original injection concentration. As a result of analyzing volatile substances using VC-P&T-GC-MS of six types of cell phone case, BHT was detected in four types and quantitatively analyzed. Maintaining the chamber at reduced pressure during the GC-MS analysis time eliminated memory effect and did not affect the next sample analysis. The volatile substances in a cell phone case were also analyzed by dynamic headspace (HT3) and GC-MS, and the results of the analysis were compared with those of VC-P&T-GC-MS. Considering the chamber volume and sample weight, the VC-P&T configuration was able to collect volatile substances more efficiently than the HT3. The VC-P&T-GC-MS system is believed to be useful for VOCs measurement of inhomogeneous large sample or devices used inside clean rooms.

• Journal of Korean Academy of Nursing
• /
• v.20 no.3
• /
• pp.430-458
• /
• 1990

Care is a central concept of nursing. Nursing would not exist without caring. Care and quality of life are closely related. Human behavior is a manifestation of culture. We can say that caring and nursing care are expression of culture. The nurse must understand the relationship of culture with care for ensure quality nursing care. But knowledge of cultural factors in nursing is not well developed. Time and in - depth study are needed to find meaningful relationships between culture and care. Nurses recognized the importance of culturally appropriate nursing There are two care systems in culturally based nursing. The folk care system and the professional nursing care system. The folk care system existed long before the professional nursing care system was introduced into this culture. If the discrepancy between these two care systems is great, the client may receive inappropriate nursing care. Culture and subcaltures are diverse and dynamic in nature. Nurses need to know the caring behaviors, patterns, and their meaning in their own culture. In Korea we have taken some first step to study cultural nursing phenomena. It is not our intent necessarily to return to the past and develop a nationalistic of nursing, but to identify the core of traditional caring and relate that to professional nursing care. Our Assumptions are as follows : 1) Care is essential for human growth, well being and survial. 2) 7here are diverse and universal forma, expressions, patterns, and processes of human care that exist transcul - turally. 3) The behaviors and functions of caring differ according to the social structure of each culture. 4) Cultures have folk and professional care values, beliefs, and practices. To promote the quality of nursing care we must understand the folk care value, beliefs, and practices. We undertook this study to understand caring in our traditional culture. The Goals of this study were as follows : 1) To identify patterns in caring behavior, 2) To identify the structural components of caring, and 3) To understand the meaning and some principles of caring. We faised several questions in this study. Who is the care-giver? Who is the care-receipient? Was the woman the major care -giver at any time? What are the patterns in caring behavior? What art the priciples underlying the caring process? We used an interdisciplinary team approach, composed of representatives from nursing and anthropology, to contribute in -depth understanding of caring through a socicaltural perspeetive. A Field study was conducted in Ro-Bong, a small agricultural kinship village. The subjects were nine women and one man aged be or more years of age. Data were collected from january 15 to 21, 1990 through opem-ended in-depth interviews and observations. The interview focused on caring behaviors sorrounding birth, aging, death and child rearing. We analysed these data for meaning, pattern and priciples of caring. In this report we describe caring behaviors surrounding childbirth. The care-givers were primarily mothers- in -low, other women in the family older than the mother - to- be, older neighbor woman, husbands, and mothers of the mother-to- be. The care receivers were the mother-to-be the baby, and the immediate family as a component of kinship. Emerging caring behavior included praying, helping proscribing, giving moral advice(Deug - Dam), showing concern, instructing, protecting, making preparations, showing consideration, touching, trusting, encouraging, giving emotional comfort, being with, worrying about, being patient, preventing problems, showing by an example, looking after bringing up, taking care of postnatal health, streng thening the health condition, entering into another's feelings(empathizing), and sharing food, joy and sorrow The emerging caring component were affection, touching, nurtuing, teaching, praying, comforting, encouraging, sharing. empathizing, self - discipline, protecting, preparing, helping and compassion. Emerging principles of. caring were solidarity, heir- archzeal relationships, sex - role distinction. Caring during birth expresses the valve of life and reflects the valued traditional beliefs that human birth is given by god and a unique unifying family event reaching back to include the ancestors and foreward to later generations. In addition, We found positive and rational foundations for traditionl caring behaviors surrounding birth, these should not be stigmatized as inational or superstitious. The nurse appropriately adopts the rational and positive nature of traditional caring behaviors to promote the quality of nursing care.

• Journal of Bio-Environment Control
• /
• v.22 no.4
• /
• pp.341-348
• /
• 2013

Maintenance of adequate soil tension or content during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil tension and content for precision irrigation would allow optimal soil water condition to crops and minimize the adverse effects of water stress on crop growth and development. This research reports on a comparison of soil water tension and content variations in differently textured soils over time under drip irrigation using two different water management methods, i.e. pulse time and required water irrigation methods. The pulse time-based irrigation was performed by turning the solenoid valve on and off for preset times to allow the wetting front to disperse in root zone before additional water was applied. The required water estimation method was a new water control logic designed by Rural Development Administration that applies the amount of water required based on a conversion of the measured water tension into water content. The use of the pulse time irrigation method under drip irrigation at a high tension of -20 kPa and high temperatures over $30^{\circ}C$ was not successful at maintaining moisture tensions within an appropriate range of 5 kPa because the preset irrigation times used for water control could not compensate for the change in evapotranspiration during day and night. The response time and pattern of water contents for all of the tested soils measured with capacitance-based sensor probes were faster and more direct than those of water tensions measured with porous and ceramic cup-based tensiometers when water was applied, indicating water content would be a better control variable for automatic irrigation. The required water estimation-based irrigation method provided relatively stable control of moisture tension, even though somewhat lower tension values were obtained as compared to the target tension of -20 kPa, indicating that growers could expect to be effective in controlling low tensions ranging from -10 to -20 kPa with the required water estimation system.

• Proceedings of the KOSOMBE Conference
• /
• v.1992 no.05
• /
• pp.27-47
• /
• 1992

Engineers have developed new instruments that aid in diagnosis and therapy Ultrasonic imaging has provided a nondamaging method of imaging internal organs. A complex transducer emits ultrasonic waves at many angles and reconstructs a map of internal anatomy and also velocities of blood in vessels. Fast computed tomography permits reconstruction of the 3-dimensional anatomy and perfusion of the heart at 20-Hz rates. Positron emission tomography uses certain isotopes that produce positrons that react with electrons to simultaneously emit two gamma rays in opposite directions. It locates the region of origin by using a ring of discrete scintillation detectors, each in electronic coincidence with an opposing detector. In magnetic resonance imaging, the patient is placed in a very strong magnetic field. The precessing of the hydrogen atoms is perturbed by an interrogating field to yield two-dimensional images of soft tissue having exceptional clarity. As an alternative to radiology image processing, film archiving, and retrieval, picture archiving and communication systems (PACS) are being implemented. Images from computed radiography, magnetic resonance imaging (MRI), nuclear medicine, and ultrasound are digitized, transmitted, and stored in computers for retrieval at distributed work stations. In electrical impedance tomography, electrodes are placed around the thorax. 50-kHz current is injected between two electrodes and voltages are measured on all other electrodes. A computer processes the data to yield an image of the resistivity of a 2-dimensional slice of the thorax. During fetal monitoring, a corkscrew electrode is screwed into the fetal scalp to measure the fetal electrocardiogram. Correlations with uterine contractions yield information on the status of the fetus during delivery To measure cardiac output by thermodilution, cold saline is injected into the right atrium. A thermistor in the right pulmonary artery yields temperature measurements, from which we can calculate cardiac output. In impedance cardiography, we measure the changes in electrical impedance as the heart ejects blood into the arteries. Motion artifacts are large, so signal averaging is useful during monitoring. An intraarterial blood gas monitoring system permits monitoring in real time. Light is sent down optical fibers inserted into the radial artery, where it is absorbed by dyes, which reemit the light at a different wavelength. The emitted light travels up optical fibers where an external instrument determines O2, CO2, and pH. Therapeutic devices include the electrosurgical unit. A high-frequency electric arc is drawn between the knife and the tissue. The arc cuts and the heat coagulates, thus preventing blood loss. Hyperthermia has demonstrated antitumor effects in patients in whom all conventional modes of therapy have failed. Methods of raising tumor temperature include focused ultrasound, radio-frequency power through needles, or microwaves. When the heart stops pumping, we use the defibrillator to restore normal pumping. A brief, high-current pulse through the heart synchronizes all cardiac fibers to restore normal rhythm. When the cardiac rhythm is too slow, we implant the cardiac pacemaker. An electrode within the heart stimulates the cardiac muscle to contract at the normal rate. When the cardiac valves are narrowed or leak, we implant an artificial valve. Silicone rubber and Teflon are used for biocompatibility. Artificial hearts powered by pneumatic hoses have been implanted in humans. However, the quality of life gradually degrades, and death ensues. When kidney stones develop, lithotripsy is used. A spark creates a pressure wave, which is focused on the stone and fragments it. The pieces pass out normally. When kidneys fail, the blood is cleansed during hemodialysis. Urea passes through a porous membrane to a dialysate bath to lower its concentration in the blood. The blind are able to read by scanning the Optacon with their fingertips. A camera scans letters and converts them to an array of vibrating pins. The deaf are able to hear using a cochlear implant. A microphone detects sound and divides it into frequency bands. 22 electrodes within the cochlea stimulate the acoustic the acoustic nerve to provide sound patterns. For those who have lost muscle function in the limbs, researchers are implanting electrodes to stimulate the muscle. Sensors in the legs and arms feed back signals to a computer that coordinates the stimulators to provide limb motion. For those with high spinal cord injury, a puff and sip switch can control a computer and permit the disabled person operate the computer and communicate with the outside world.

• Journal of the Society of Disaster Information
• /
• v.9 no.4
• /
• pp.449-461
• /
• 2013

As the hydrofluoric acid leak in Gumi-si, Gyeongsangbuk-do or hydrochloric acid leak in Ulsan, Gyeongsangnam-do demonstrated, chemical related accidents are mostly caused by large amounts of volatile toxic substances leaking due to the damages of storage tank or pipe lines of transporter. Safety assessment is the most important concern because such toxic material accidents cause human and material damages to the environment and atmosphere of the surrounding area. Therefore, in this study, a hydrofluoric acid leaked from a storage tank was selected as the study example to simulate the leaked substance diffusing into the atmosphere and result analysis was performed through the numerical Analysis and diffusion simulation of ALOHA(Areal Location of Hazardous Atmospheres). the results of a qualitative evaluation of HAZOP (Hazard Operability)was looked at to find that the flange leak, operation delay due to leakage of the valve and the hose, and toxic gas leak were danger factors. Possibility of fire from temperature, pressure and corrosion, nitrogen supply overpressure and toxic leak from internal corrosion of tank or pipe joints were also found to be high. ALOHA resulting effects were a little different depending on the input data of Dense Gas Model, however, the wind direction and speed, rather than atmospheric stability, played bigger role. Higher wind speed affected the diffusion of contaminant. In term of the diffusion concentration, both liquid and gas leaks resulted in almost the same $LC_{50}$ and ALOHA AEGL-3(Acute Exposure Guidline Level) values. Each scenarios showed almost identical results in ALOHA model. Therefore, a buffer distance of toxic gas can be determined by comparing the numerical analysis and the diffusion concentration to the IDLH(Immediately Dangerous to Life and Health). Such study will help perform the risk assessment of toxic leak more efficiently and be utilized in establishing community emergency response system properly.

• Journal of Chest Surgery
• /
• v.39 no.1 s.258
• /
• pp.18-27
• /
• 2006

Background: Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly, but is one of the most common causes of myocardial ischemia which would result in high mortality within the first year of life. This is our early result of the surgical management for these patients. Material and Method: From June 1989 to July 2003, 6 patients with ALCAPA and one patient with ARCAPA (Anomalous origin of the Right coronary artery from the pulmonary artery) underwent surgical repair. We have reviewed the all medical records, electrocardiogram, chest X-ray and echocardiography retrospectively. Result: Three of the patients were boys and four were girls. The median age at the operation was 5.4 months (Range: 3$\∼$33 months). The average body weight of at the operation was 6.7 kg (Range: 3.7$\∼$11.3 kg). A mean follow up period was 18 months. Only 3 patients were initially diagnosed as ALCAPA. And 3 patients had moderate mitral regurgitation. Immediate coronary artery reimplantation on diagnosis with the aim of restoring a two-coronary system circulation was done. The average bypass time was 114$\pm$37 minutes, and the average aortic cross clamping time was 55$\pm$22 minutes. The average stay of intensive care unit was 5$\pm$3 days, the mean mechanical ventilator time was 38$\pm$45 hours and the hospital stay after operation was 12$\pm$5 days. There were significant improvements in electrocardiogram and chest X-ray of the all patients except one late death patient. The ventricular function showed almost normal recovery after operation; the EF (Ejection Fraction) increased from 41.2$\pm$ 10.3$\%$ to 60.5$\pm$ 15.8$\%$ within 1 month and to 59.8$\pm$13.9$\%$ within 1 year after operation, the SF (Shortening Fraction) increased from 23.6$\pm$4.7$\%$ to 38.6$\pm$8.4$\%$ within 1 month and to 37.4$\pm$7.9$\%$ within 1 year after operation, LVEDDI (Left Ventricular End-diastolic Dimension Index) decreased from 100.8$\pm$25.6 mm/$m^{2}$ to 90.3$\pm$ 19.2 mm/$m^{2}$ within f month and to 79.3$\pm$ 15.8 mm/$m^{2}$ within 1 year after operation. Concomitant mitral repair was done in two patients with anterior mitral leaflet prolapse. In every patient, mitral valve showed less than mild regurgitation during follow up. One late death occurred in which patient Dor procedure was applied 10 months after initial operation due to the dilated cardiomyopathy Conclusion: In the management of this rare and could be fatal Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA), early suspicion and correct diagnosis is of most important. But, after diagnosis, immediate restoration of 2 coronary systems could result in good outcome.

• Journal of Chest Surgery
• /
• v.31 no.5
• /
• pp.472-480
• /
• 1998

We reviewed the surgical results of intracardiac lateral tunnel Fontan procedure for the repair of functional single ventricles. Between 1990 and 1996, 104 patients underwent total cavopulmonary anastomosis. Patients' age and body weight averaged 35.9(range 10 to 173) months and 12.8(range 6.5 to 37.8) kg. Preoperative diagnoses included 18 tricuspid atresias and 53 double inlet ventricles with univentricular atrioventricular connection and 33 other complex lesions. Previous palliative operations were performed in 50 of these patients, including 37 systemic to pulmonary artery shunts, 13 pulmonary artery bandings, 15 surgical atrial septectomies, 2 arterial switch procedures, 2 resections of subaortic conus, 2 repairs of total anomalous pulmonary venous connection and 1 Damus-Stansel-Kaye procedure. In 19 patients bidirectional cavopulmonary shunt operation was performed before the Fontan procedure and in 1 patient a Kawashima procedure was required. Preoperative hemodynamics revealed a mean pulmonary artery pressure of 14.6(range 5 to 28) mmHg, a mean pulmonary vascular resistance of 2.2(range 0.4 to 6.9) wood-unit, a mean pulmonary to systemic flow ratio of 0.9(range 0.3 to 3.0), a mean ventricular end-diastolic pressure of 9.0 (range 3.0 to 21.0) mmHg, and a mean arterial oxygen saturation of 76.0(range 45.6 to 88.0)%. The operative procedure consisted of a longitudinal right atriotomy 2cm lateral to the terminal crest up to the right atrial auricle, followed by the creation of a lateral tunnel connecting the orifices of either the superior caval vein or the right atrial auricle to the inferior caval vein, using a Gore-Tex vascular graft with or without a fenestration. Concomitant procedures at the time of Fontan procedure included 22 pulmonary artery angioplasties, 21 atrial septectomies, 4 atrioventricular valve replacements or repairs, 4 corrections of anomalous pulmonary venous connection, and 3 permanent pacemaker implantations. In 31, a fenestration was created, and in 1 an adjustable communication was made in the lateral tunnel pathway. One lateral tunnel conversion was performed in a patient with recurrent intractable tachyarrhythmia 4 years after the initial atriopulmonary connection. Post-extubation hemodynamic data revealed a mean pulmonary artery pressure of 12.7(range 8 to 21) mmHg, a mean ventricular end-diastolic pressure of 7.6(range 4 to 12) mmHg, and a mean room-air arterial oxygen saturation of 89.9(range 68 to 100) %. The follow-up duration was, on average, 27(range 1 to 85) months. Post-Fontan complications included 11 prolonged pleural effusions, 8 arrhythmias, 9 chylothoraces, 5 of damage to the central nervous system, 5 infectious complications, and 4 of acute renal failure. Seven early(6.7%) and 5 late(4.8%) deaths occured. These results proved that the lateral tunnel Fontan procedure provided excellent hemodynamic improvements with acceptable mortality and morbidity for hearts with various types of functional single ventricle.