• Journal of Industrial Technology
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• v.32 no.A
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• pp.57-64
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• 2012

In order to examine the tailorability of advanced sewage treatment of a separated sewer pipe, we observed the quality of leaked water in a reactor. A2C affiliation and MBR affiliation decreased by over 78% in cases of BOD, COD, and SS. SBR affiliation decreased by 79.1% in a case of T-N. Overall, the efficiency of T-N on the above affiliations was low. SS had the high efficiency in MBR affiliation. In the end, examination of water quality improvement showed that the quality was improved from 20% to 90%; hence, it is expected that this treatment can protect the water resources of the Hongcheon River and makes it easier to use the water of the river.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.2
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• pp.91-96
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• 2014

An acoustical model for detecting the leak location in a buried gas pipeline has been developed. This model is divided into an experimental model for sound diagnosis, and a theoretical model for sound prediction, which is based on the transfer matrix method, representing the sound pressure and the volume velocity as state variables. The power spectrum is measured by attaching only one microphone to the closed end pipe. It has been shown that the response magnitude of acoustic pressure signals calculated by the acoustical model depends upon the thickness and diameter of a pinhole. The validity for the acoustical model has been verified through a comparison between the measured and calculated results.

• Transactions of Materials Processing
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• v.26 no.5
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• pp.271-276
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• 2017

A tee is the most common pipefitting used to combine or divide fluid flow. Tees can connect pipes of different diameters or change the direction of a pipe run. To manufacture tee type of stainless steel pipe, combinations of punch piercing and burr forming have been widely used in the industry. However, such method is considerably time consuming with regard to performing empirical work necessary to attain process conditions to prevent upper end tearing of the tee product and meet target tee height. Numerous experiments have shown that the piercing profile is the main cause of defects mentioned above. Furthermore, the mold design is formed through trial and error according to pipe diameters and changes in requirements. Thus, the objective of this study was to perform piercing and burring process analysis via finite element analysis using DYNAFORM to resolve problems mentioned above. An optimization design method was used to determine the piercing punch profile. Three radii of the piercing punch (i.e., large, small, and joined radii) were selected as design variables to minimize thinning of a tee pipe. Based on results of correlation and multiple regression analyses, we developed a predictive approximation model to satisfy requirements for both thickness reduction and target height. The new piercing punch profile was then applied to actual tee forming using the developed prediction equation. Model results were found to be in good agreement with experimental results.

• Management & Information Systems Review
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• v.24
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• pp.45-71
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• 2008

These days the international environmental regulations of the developed countries, especially from the EU, are rapidly changed to the regulations of product-based environment from a conventional end-of-pipe environmental technology. Especially the motive in this paper come from the EU's electrical and electronic equipment environment regulation. It may affect much to whole export of Korea Firms Integrated product policy has the potential to increase not only competitive power in today's global market, but also trade compatibility between countries. Furthermore it is important to make a contribution to sustainable development. CEOs must change their notions about firms' environmental policy from the end-of-pipe approach to the sustainable approach to improve company's competitive power. As emphasized a paradigm of naw environmental management by EU' environmental directives, the company must establish clean production system to save resources and reduces pollutant. Also Korean Company constructs a systematical network to collect EU' environmental regulation information which are changing rapidly. Large company will cooperate with small and medium-sized firm for their win-win strategy in the field of environmental management. Also it is necessary to make the domestic regulations of product-based environment to meet the international environmental regulations.

• Nuclear Engineering and Technology
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• v.48 no.6
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• pp.1404-1411
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• 2016

Pipe wall thinning in the secondary piping system of a nuclear power plant is currently a major problem that typically affects the safety and reliability of the nuclear power plant directly. Regular in-service inspections are carried out to manage the piping system only during the overhaul. Online thickness monitoring is necessary to avoid abrupt breakage due to wall thinning. To this end, a transducer that can withstand a high-temperature environment and should be installed under the insulation layer. We propose a thin plate type of embedded ultrasonic transducer based on magnetostriction. The transducer was designed and fabricated to measure the thickness of a pipe under a high-temperature condition. A number of experimental results confirmed the validity of the present transducer.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.6
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• pp.75-82
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• 2002

Design for a quiet operation of fluid power system requires the understanding of noise and vibration characteristics of the system. It's not easy to analyze noise problem in hydraulic cylinder used in typical actuator Because they've got complex fluid dynamics. One of the fundamental problems associated with the hydraulic system is the pulsating flow in pipe lines, which can be tackled by the analysis under simplifying assumptions. The present study focuses on theoretic analysis and experimental study on the dynamics of laminar pulsating flow in a circular pipe. We analyze the propagation characteristics of the pressure pulse within a hydraulic pipe line taking into account the pulsating flow frequency variation. We also measure instantaneous pressure pulses within pipe line to identify the transfer functions. We conduct series of experiments to investigate the propagation characteristics of pressure pulse for various pressure of pulsating flow. The working fluid of the present study is ISO VG46 and the temperature ranges from 20 to $60^{\circ}$ with normal pressure at 4000kPa. The flow rate is measured by using an ultrasonic flow meter. Pressures at fixed upstream and downstream positions are measured concurrently. The electric signals of the pressure sensor are stored and analyzed using a system analyzer(PKE 983 series). The frequency is varied in the range of 10~500Hz. The Reynolds number is kept below 2,000. In the present study, boundary condition was varied by installing a surge tank and an orifice at the end of pipe. Experimental and theoretical results were compared each other under various boundary conditions.

• Clean Technology
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• v.11 no.2
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• pp.75-81
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• 2005

With a development of nanotechonlogy, the concept of environmental technology has been changed from end-of-pipe to green or clean technology. Nanoscience or nanotechnology involves studying and working with matter on a nano-scale. In this article, we introduced the necessity for the development of environmental sensing/monitoring technologies with nanotechnologies for the clean technology.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.8
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• pp.449-455
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• 2017

Process input data including material and energy, process output data including product, co-product and its environmental emissions of the reference and target processes were collected and analyzed to evaluate the process performance. Environmentally problematic input/environmental emissions of the manufacturing processes were identified using these data. Significant process inputs contributing to each of the environmental emissions were identified using multiple regression analysis between the process inputs and environmental emissions. Optimum combination of the end-of-pipe technologies for treating the environmental emissions considering economic aspects was made using the linear programming technique. The cement manufacturing processes in Korea and the EU producing same type of cement were chosen for the case study. Environmentally problematic input/environmental emissions of the domestic cement manufacturing processes include coal, dust, and $SO_x$. Multiple regression analysis among the process inputs and environmental emissions revealed that $CO_2$ emission was influenced most by coal, followed by the input raw materials and gypsum. $SO_x$ emission was influenced by coal, and dust emission by gypsum followed by raw material. Optimization of the end-of-pipe technologies treating dust showed that a combination of 100% of the electro precipitator and 2.4% of the fiber filter gives the lowest cost. The $SO_x$ case showed that a combination of 100% of the dry addition process and 25.88% of the wet scrubber gives the lowest cost. Salient feature of this research is that it proposed a method for identifying environmentally problematic input/environmental emissions of the manufacturing processes, in particular, cement manufacturing process. Another feature is that it showed a method for selecting the optimum combination of the end-of-pipe treatment technologies.

• Smart Structures and Systems
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• v.9 no.5
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• pp.461-472
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• 2012

This study proposes an optics-based active sensing system for continuous monitoring of underground pipelines in nuclear power plants (NPPs). The proposed system generates and measures guided waves using a single laser source and optical cables. First, a tunable laser is used as a common power source for guided wave generation and sensing. This source laser beam is transmitted through an optical fiber, and the fiber is split into two. One of them is used to actuate macro fiber composite (MFC) transducers for guided wave generation, and the other optical fiber is used with fiber Bragg grating (FBG) sensors to measure guided wave responses. The MFC transducers placed along a circumferential direction of a pipe at one end generate longitudinal and flexural modes, and the corresponding responses are measured using FBG sensors instrumented in the same configuration at the other end. The generated guided waves interact with a defect, and this interaction causes changes in response signals. Then, a damage-sensitive feature is extracted from the response signals using the axi-symmetry nature of the measured pitch-catch signals. The feasibility of the proposed system has been examined through a laboratory experiment.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.1
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• pp.67-73
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• 2008

The most common method of pipeline inspection is to use a remote-controlled-machine equipped with a CCTV, which, however, has many limitations to accurately inspect pipeline condition. In case of a typical CCTV, since the camera looks at the end point of the pipe, the locations of the defects and distance-readings are often different. In addition, the quality and accuracy of the inspection is highly dependent on the operator's skill and experience. In this research a new system is developed by use of the image processing techniques and the lens combination. The image acquisition system is developed that acquires the front and the side view of the pipe simultaneously. Side view unwrapping and stitching technology using image process techniques are developed which delivers high resolution image data.