• Journal of Power System Engineering
• /
• v.15 no.3
• /
• pp.65-69
• /
• 2011

This paper introduces the multi-coil eddy current sensor and its characteristic in magnetic material gas turbine rotor. In the past, magnetic particle inspection method was used for qualitative defect evaluation in magnetic material gas turbine rotor. And the ultrasonic inspection method was used for quantitative defect evaluation. Nowadays, eddy current method is used in magnetic gas turbine rotor inspection due to advanced sensor design technology. We developed multi-coil eddy current sensor for the rotor dovetail inspection. At first, rotor stress is analyzed for the determination of sensor position and number. The sensor coils are designed to cover the stress concentration area of rotor dovetail. We select optimum frequency according to material standard penetration data and experiment results. The rotor mock-up and artificial defects were made for the signal detection and resolution analysis of multi-coil eddy current sensor. The results show that signal detection and resolution capabilities are enhanced in comparison to the commercialized sensor enough for the gas turbine rotor inspection. So, this developed multi-coil eddy current sensor substituted for commercialized one and it applied in real gas turbine rotor inspection.

• Journal of Haehwa Medicine
• /
• v.20 no.1
• /
• pp.51-63
• /
• 2011

There are two methods in inspection diagnosis(望診), the viewing shape(觀形) and the inspecting color(察色). Acquiring proper analysis from viewing shape(觀形) requires several standards of shape that can be compared with. We can identify major defects and flaws of the shape from comparing it with the standards that is defined as very normal shape. Also, It can eventually provide us interpretation of health related meanings of the objective shapes. Those standards need symmetrical and proportional details. In this research, I put some physiognomy and inspection diagnosis related documents, and standards for restorative plastic surgery together to suggest standards on viewing shape diagnosis of nose which is one of the most important spot in facial inspection. It is expected to improve delicacy of Oriental medine's inspection diagnosis, as the result of the comparison between plastic surgery and inspection diagnosis.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.7 no.3
• /
• pp.117-127
• /
• 2001

On this research, recognizing that ship inspection is closely related in improving ship safety', the importance of active quality managements of ship inspection has been notified. This paper aims to explore effective ways to improve inspection service and develop customer-centered inspection administration, by carrying out a case study on K Company. The methods applied for this research project are as follows, 1) sector-based examination of the existence of the ISO 9001 system; 2) evaluation of the operation of the system; 3) conduction of a survey questionnaire with the participation of all staff and inspection companies to analyze customer satisfaction of their inspection service, and 4) statistical analysis of the data collected from the survey questionnaire.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.4
• /
• pp.446-451
• /
• 2011

Recent trends for the miniaturization and weight reduction of portable electronic parts have driven uses of subminiature components. Assembly of the miniaturized components requires subminiature screws of which pitch sizes are micrometer scale. To produce such subminiature screws with high precision threads, not only a precision forming technology but also a high-precision measurement technology is required. The present study covers the development of a vision inspection system for precision screws for the automatic measurement of subminiature screws with high speed and reliability. In this study, the feeding unit that transfers the subminiature screws to the inspection unit is investigated through finite element(FE) analysis. The vibration characteristics of the feeding unit are predicted through FE analyses, from which we can determine whether the subminiature screw can be stably fed into the inspection unit or not. The effects of several design parameters on the vibration characteristics are also discussed.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.7 no.3
• /
• pp.8-14
• /
• 2011

The clogging of the flow area at the tube support plates(TSPs), especially at the upper TSPs results in the water level oscillation of a steam generator during normal operation. A reduction of the TSP flow area causes to increase in pressure drop within the two-phase flow zone, which destabilizes the boiling flow through the tube bundle. This phenomenon was occasionally observed at a few domestic and foreign nuclear power plants. One of the methods for defining the flow area clogging is visual inspection, which is the most effective inspection method. The results of the visual inspection for TSPs' flow area are clogging images on TSPs' quartrefoil lobes. These images are complexly distorted due to lens aberration and external factors like the distance to a subject and angle etc. In this work, we developed the analysis algorithm for clogging image of the TSP flow area of steam generators. For this purpose, we designed an image verification device applicable to the camera employed in the field for visual inspection and then, we demonstrated the validity of image analysis algorithm by using this device and commercial autoCAD program.

• Corrosion Science and Technology
• /
• v.7 no.4
• /
• pp.208-211
• /
• 2008

Safety operation of main pipelines is primarily provided by anticorrosive monitoring. Anticorrosive monitoring of oil pipeline transportation objects is based on results of complex corrosion inspections, analysis of basic data including design data, definition of a corrosion residual rate and diagnostic of general equipment's technical condition. All the abovementioned arrangements are regulated by normative documents. For diagnostics of corrosion-technical condition of oil pipeline transportation objects one presently uses different methods such as in-line inspection using devices with ultrasonic, magnetic or another detector, acoustic-emission diagnostics, electrometric survey, general external corrosion diagnostics and cameral processing of obtained data. Results of a complex of diagnostics give a possibility: $\cdot$ to arrange a pipeline's sectors according to a degree of corrosion danger; $\cdot$ to check up true condition of pipeline's metal; $\cdot$ to estimate technical condition and working ability of a system of anticorrosive protection. However such a control of corrosion technical condition of a main pipeline creates the appearance of estimation of a true degree of protection of an object if values of protective potential with resistive component are taken into consideration only. So in addition to corrosive technical diagnostics one must define a true residual corrosion rate taking into account protective action of electrochemical protection and true protection of a pipeline one must at times. Realized anticorrosive monitoring enables to take a reasonable decision about further operation of objects according to objects' residual life, variation of operation parameters, repair and dismantlement of objects.

• Korean Journal of Occupational Health Nursing
• /
• v.12 no.2
• /
• pp.99-109
• /
• 2003

Although occupational accidents caused by presses are found to be the highest in manufacturing industrial groups, there are no study regarding to annulment for periodical inspection of press. The purpose of this study was to evaluate the economic benefit of periodical inspection of press for preventing accidents. The cost-benefit analysis in this study was conducted to evaluate the relative magnitude of benefit to cost. Study samples were 26 and years analysed were 1995, 1996, 1998 and 1999. Personal interviews with safety managers were held from October 7 to November 2, 2002. Costs of the periodical inspection program were compared with the benefit of accident that caused by presses. Costs and benefits were calculated at an discount rate of 5%. The benefit-cost ratio was 5.7. The sensitivity analysis for the discount rate, the number of press, and size of industry showed that every benefit-cost ratios were upper than one(1.0). The results of this study suggested that periodical inspection for press is important program for preventing accident and the regulation for periodical inspection program should be reenforced by government.

• Journal of the Semiconductor & Display Technology
• /
• v.14 no.4
• /
• pp.67-71
• /
• 2015

Product of technology developed in this study is an external interface for controlling the equipment of pendant key remote control system circuit board, and it is used in the electronic component test equipment system. Main control system module is in the role as a device for controlling the various control devices that make up the integrated system for microscopic examination at the request of the host computer engineers to control the inspection equipment. The pentane-key interface module to its role as a device for controlling the various control devices that make up the integrated system for microscopic examination at the request of the host computer for the engineer to control the inspection equipment. Development of the control system can be expected in the configuration of a system for efficient and accurate inspection of high-precision parts.

• Journal of the Society of Naval Architects of Korea
• /
• v.57 no.1
• /
• pp.1-7
• /
• 2020

In general, an inspection schedule is established based on the long-term fatigue life during the design stage. However, in the design stage, it is difficult to clearly identify the uncertainty factors affecting long-term fatigue life. In this study, the probabilistic fatigue life assessment was conducted in accordance with the methodology of DNV-GL. Firstly, The initial crack distribution estimated through the initial crack propagation analysis was updated by reflecting the results of crack inspection. Secondly, the updated crack distribution was compared with the initial crack distribution, and the probability of failure was updated with the effect of crack inspection.

• Structural Engineering and Mechanics
• /
• v.64 no.3
• /
• pp.347-352
• /
• 2017

The poor maintenance practice increases the possibility of system failure. Subsequently, the consequences of failure fall on the aspects of output, safety and healthy, environmental integrity, system quality, and customer satisfaction. Conditionbased maintenance is seen as a potential strategy to improve performance. Whereby, the key success factor of this maintenance strategy is identified as the system inspection. This study aims to investigate the association between system breakdown rate and frequency of inspection. A mixed method approach is implemented by distributing questionnaire and interviewing for data collection. Subsequently, descriptive analysis, correlation analysis and regression are adopted to analyse the collected data from 100 respondents and the results are validated with interview data of 10 interviewees. The research result establishes significant relationship between the system breakdown rate and the frequency of inspection. Additionally, the result of regression analysis confirms that the frequency of inspection is the significant predictor of system breakdown rate. Planning of accurate inspection frequency is crucial to secure the system performance. Hence, the research signifies the importance to carry out regular inspection towards the building systems and components. As a recommendation, the maintenance personnel should assess the risk criticality of the building systems. Then, continuously monitor the condition of critical building systems; regularly inspect the condition of non-critical building systems and randomly inspect all of them.