• Journal of the Korean Society of Mechanical Technology
• /
• v.20 no.6
• /
• pp.783-789
• /
• 2018

This paper investigates the relationship of voltage and current waveform between normal piezo injector and deterioration abnormal piezo injector. The experimental methods using Pico oscilloscope and GDS scan tool are employed to measure current and voltage waveform and fuel pressure of piezo injector. The experiment is carried out during no-load condition. A summary of the important results are as follows. 1) In case of normal injector, the fluctuation of duration time of piezo injector was linearly and regularly decreased with increasing engine speed, but the that of deterioration piezo injector was irregularly decreased with increasing engine speed. 2) In main injection, the peak value of the current waveform of abnormal injector was larger than that of normal injector, the duration time of deteriorated abnormal injector was less than that of normal injector at 800rpm and 1500rpm, but the duration time of deteriorated abnormal injector was larger than that of normal injector at 2000rpm and 3000rpm. This irregularity appears to be caused by the deterioration of the injector.

• Corrosion Science and Technology
• /
• v.23 no.2
• /
• pp.83-92
• /
• 2024

A hot-dip simulator was utilized to replicate abnormal coating buildup observed during line stops at galvanize lines, assessing the influence of processing conditions on buildup (up to 14 mm/side). Steel samples from 19 coils (comprising IF, BH, LCAK, HSLA, DP600-DP1180, Si: 0.006 - 0.8 wt%, P: 0.009 - 0.045 wt%) were examined to explore the phenomenon of heavy coating growth. It was discovered that heavy coating buildup (~3 mm/h) and rapid strip dissolution (~0.17 mm/h) in a GA or GI pot can manifest with specific combinations of steel chemistry and processing conditions. The results reveal the formation of a unique coating microstructure, characterized by a blend of bulky Zeta crystals and free Zn pockets/networks due to the "Sandlin" growth mechanism. Key variables contributing to abnormal coating growth include steel Si content, anneal temperature, dew point in heating and soaking furnaces, Zn pot temperature, Zn bath Al%, and cold-rolling reduction%. At ArcelorMittal Dofasco galvanize lines, an automatic online warning system for operators and special scheduling for incoming Si-bearing steels have been implemented, effectively preventing further heavy buildup occurrences.

• Korean Journal of Radiology
• /
• v.24 no.8
• /
• pp.752-760
• /
• 2023

Radiologists and trauma surgeons should monitor for early killers among patients with thoracic trauma, such as tension pneumothorax, tracheobronchial injuries, flail chest, aortic injury, mediastinal hematomas, and severe pulmonary parenchymal injury. With the advent of cutting-edge technology, rapid volumetric computed tomography of the chest has become the most definitive diagnostic tool for establishing or excluding thoracic trauma. With the notion of "time is life" at emergency settings, radiologists must find ways to shorten the turnaround time of reports. One way to interpret chest findings is to use a systemic approach, as advocated in this study. Our interpretation of chest findings for thoracic trauma follows the acronym "ABC-Please" in which "A" stands for abnormal air, "B" stands for abnormal bones, "C" stands for abnormal cardiovascular system, and "P" in "Please" stands for abnormal pulmonary parenchyma and vessels. In the future, utilizing an artificial intelligence software can be an alternative, which can highlight significant findings as "warm zones" on the heatmap and can re-prioritize important examinations at the top of the reading list for radiologists to expedite the final reports.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.669-670
• /
• 2008

In this paper, we present a real-time system to detect abnormal events on gas pipes, based on the signals which are observed through the audio sensors attached on them. First, features are extracted from these signals so that they are robust to noise and invariant to the distance between a sensor and a spot at which an abnormal event like an attack on the gas pipes occurs. Then, a classifier is constructed to detect abnormal events using neural networks. It is a combination of two neural network models, a Gaussian mixture model and a multi-layer perceptron, for the reduction of miss and false alarms. The former works for miss alarm prevention and the latter for false alarm prevention. The experimental result with real data from the actual gas system shows that the proposed system is effective in detecting the dangerous events in real-time with an accuracy of 92.9%.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.26 no.4
• /
• pp.469-474
• /
• 2016

Abnormal sound was heard from a heat exchanger of condensate water system in a nuclear power plant, which was identified as impact sound of a loose part later. Nuclear power plants are normally equipped with loose part monitoring system for primary water system, but not for secondary water system. The abnormal sound was analyzed by using the impact signal-processing methodology based on the Hertz theory. The predicted results for impact location and size of the loose part showed good agreement with those of the actual loose part found during the overhaul period in the plant. So, this analysis methodology for the impact signal will be widely utilized for the primary and secondary side of the nuclear power plant.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.05a
• /
• pp.1049-1052
• /
• 2006

Object of this study is to develop an Stack Silencer System for quieting abnormal noise around power plant. Abnormal noise gets resident people to feel uncomfortable. Stack Silencer System is to minimize pressure loss of exhaust gas and to maximize noise reduction effect from abnormal noise frequency band. Stack Silencer System is installation in stack and absorbing material is an aluminum foam. Reduction effect measures insertion loss of $8.2{\sim}19.4dB$ by Stack silencer installation. After Stack Silencer System installation, pressure loss of exhaust gas measured $5{\sim}9mmH_2O$.

• Journal of radiological science and technology
• /
• v.24 no.1
• /
• pp.33-41
• /
• 2001

This study is to get preliminary data for an effectiveness evaluation of abdominal examination and improvement of it. Abnormal cases of abdominal ultrasonography are classified by sex, frequency, diagnosis and age. 4,924 examinees were included at a university hospital of health promotion center from January to December in 1999. The results are as follows. 1. According to the distribution of sex, there are more male patients(55.0%) than females patients(48.0%). For men, 40's showed the highest percentage among examinees. For women, 50's were the highest. 2. The reason that they visited the health promotion center was that 'they wanted to check their health status'. This answers were reported the highest(59.3%). 3. Patients that had abnormal cases of abdominal ultrasonography were 48.3%. Liver, kidney, gallbladder showed the highest percentage of abnormal cases in order of organs. Additionally, abnormal cases were discovered in liver cases. 4. According to the frequency of abnormal cases among examinees, the slight fatty liver were the highest regardless of sex. Men had the slight fatty liver, kidney simple cyst, liver calcification and liver simple cyst in order of abnormal cases. Women showed the slight fatty liver kidney simple cyst, kidney calcification, liver simple cyst, and blood vessel tumor in order of abnormal cases. 5. For the abnormal cases of liver by sex and age, the 50's reported the highest number of abnormal cases in men(299 patients). In addition, 60's had the highest of disease rata 47.8%. For women, 50's reported the highest number of abnormal cases(361 patients). Over 70's patients had the highest of disease rata 52.6%. For kidney, men and women showed the highest number of abnormal cases -62 vs 44 respectively. Over 70's patients had the highest percentage of disease rata-23.2% vs 14.0% respectively. For gallbladder, the number of abnormal cases were the most in men's 60's (31 patients) and in women's in the same age group (32patients). Disease showed the highest percentage in men's 60's(7.6%) and in women's 70's (14.0%). 6. According to malignant tumor, 17patients were liver cancer, 2patients stomach ca and 1pt kidney cancer. 7. The relationship between the malignant tumor and the examination motive was that 'they wanted to check their health status(41.0%)' and 'regular checkup (24.0%)'.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2263-2268
• /
• 2011

THE VIBRATION MODE OF RAILWAY VEHICLE IS DIFFICULT TO FIND OUT THE CHARACTERISTICS OF MOTION DURING THE OPERATION ON THE TRACK BECAUSE THESE HAPPEN TO INDEPENDENCE OR DUPLICATION MOTION CAUSED BY VEHICLE, WHEEL/RAIL INTERACTION, TRACK IRREGULARITY AND FAILURE OF THE SUSPENSION & POWER TRANSMISSION DEVICE ETC. IT IS NAMED AN ABNORMAL VIBRATION THAT THE VIBRATION, WHICH WAS PASSED THE PRIMARY AND SECONDARY SUSPENSION, IS AFFECTED TO THE PASSENGER OR DRIVER WITHOUT DAMPING. THIS PAPER DESCRIBES AN EXPERIENCE EVALUATION TO FIND OUT THE CAUSE OF AN ABNORMAL VIBRATION WHICH WAS HAPPEN AT THE CAB OF POWER CAR IN KTX-SANCHEON TRAINSET WHEN ON RUNNING AT HIGH SPEED ZONE.

• Journal of Environmental Impact Assessment
• /
• v.23 no.3
• /
• pp.220-226
• /
• 2014

This study investigated temporal-spatial and variations in Geostationary Ocean Color Imager (GOCI) products of parameters total suspended solids (TSS) and chlorophyll-a in the North Marine Areas of East China Sea.GOCI data were collected daily from February 2012 to December 2012. The higher chlorophyll-a values were observed during the investigation period. The relatively large increase in TSS and chlorophyll-a at the sampling stations coupled with typhoon events during the summer rainy period. The abnormal chlorophyll-a concentration was mainly driven by meteorological factors such as typhoon and rainfall in the coastal areas of Jeju and the North Marine Areas of East China Sea. The abnormal high chlorophyll-a concentration at the majority of the coastal stations indicate eutrophication of coastal waters, especially Red tide. The events such as eutrophication and abnormal high chlorophyll-a concentration may potentially influence outbreak of Red Tide, detected with GOCI parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.356-360
• /
• 2003

At rotating machinery, Many factors had caused vibration. especially one of the major factor is mass unbalance. A sort of mass unbalance are followings; Static, Coupling, Single and Dynamic. In this paper, We had investigated abnormal vibration due to mass unbalance that changed phase whenever starting of steam Turbine at Combined Cycle.