• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.11
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• pp.789-796
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• 2007

It has been noted, in case of the apartments in collective form, the drainage noise from cleaning of toilet causes many problems in the basement and adjacent rooms, mainly hampering the pleasant housing environment. The problems are increasingly raised by civil complaints with the public offices. Therefore, if the drainage noise generates when wash out of toilet bowl is grasped how the characteristics change according to the sorts of drainpipe, it is considered that the establishment of an effective sound insulation countermeasure could be possible when a civil petition against the drainage noise of apartment house is submitted hereafter. On such viewpoint, this study measured and analyzed the characteristics of drainage noise per the type of drainage pipe, according to KS A ISO $1996-1{\sim}3$, with the horizontal branch pipe and riser pipes in the drainage noise experiment chamber which has the characteristics of the anechoic room. In the result, the pipe type with excellent noise reduction function. The result of this study is considered to become available as fundamental data, to take actions on reduction of drainage noise of the ceiling piping method.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.157-162
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• 2005

It is necessary for us to research and analyze of Open Housing in order to change new housing system, because exiting multi family housing is lack of flexibility and easy remodeling. The purpose of this study is to supply and grasp basic planning and design data for flexibility of Open Housings in Korea. This study is based on the literature survey and actual investigation through visiting 17 open housing sites from 1995 to 2005 in Netherlands, Finland and Japan, which are main Open Housing. We analyzed the planning methods and elements for flexibility of open housing block and unit plan, and described the contents of analyses. We found a lot of planning and design methods-supplying option plan and user participation before occupation, various structural system for openness, common piping shaft location, slab-down and applying access flooring system, movable and demountable partition wall system etc. -applied to the open housings, and findings are applicable to the planning and designing works of apartment housings in Korea.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.10
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• pp.953-959
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• 2010

This paper deals with the process to identify the exciting forces generated from a rotary compressor. The equation of motion of a rigid compressor supported by several mounts was derived with 6 degree of freedom. The mass moment of inertia of compressor and the stiffness of rubber mounts were also identified by experiments. The exciting force at the center of mass of the compressor were estimated from the acceleration data measured at compressor shell. The piping system connected to the compressor was modeled. The acceleration of a pipe was predicted numerically by using the predicted exciting force. The numerical results showed good agreement with experimental results, which validated the identified exciting force.

• Corrosion Science and Technology
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• v.18 no.3
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• pp.78-85
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• 2019

The International Maritime Organization (IMO) will administer a new 0.5% global sulfur cap on fuel content from 1 January 2020, lowering from the present 3.5% limit. Seawater $SO_x$ (sulfur oxide) scrubbing is especially spray scrubbing and a promising alternative to complying with the IMO regulation. However, the ionization of $SO_2$ (sulfur dioxide) and the $H_2SO_4$ (sulfuric acid) formed from $SO_3$ (sulfur trioxide) is proposed to accelerate corrosion of the internal seawater pipe. Apparently, the corrosion of the scrubber seawater piping system occurs in a severe and frequent manner. Hence, in this study, electrochemical measurement and weight loss of carbon steel (used as seawater pipe in most of the ships) in diluted sulfuric acid solution were investigated to determine corrosion rate, corrosion current density, corrosion potential, electrochemical behavior, and impressed-current density. Accordingly, the corrosion rate of carbon steel sheet in various diluted sulfuric acid solutions was observed to be greater than that in natural seawater, thus suggesting the fundamental data to deal with corrosion problems in scrubber seawater pipe.

• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1805-1815
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• 2019

While nickel-based alloys have been widely used for power plants due to corrosion resistance and good mechanical properties, during the last couple of decades, failures of nuclear components increased gradually. One of main degradation mechanisms was primary water stress corrosion cracking at dissimilar metal welds of piping and reactor head penetrations. In this context, precise estimation of welding effects became an important issue for ensuring reliability of them. The present study deals with a series of finite element analyses and crack growth rate evaluation of Alloys 690/152. Firstly, variation of residual stresses and equivalent plastic strains was simulated taking into account welding of a cylindrical block. Subsequently, extraction and pre-cracking of compact tension (CT) specimens were considered from different locations of the block. Finally, crack growth curves of the alloys and heat affected zone were developed based on analyses results combined with experimental data in references. Characteristics of crack growth behaviors were also discussed in relation to mechanical and fracture parameters.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.1-9
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• 2020

In highly complex EPC(engineering, procurement, construction)-based manufacturing processes such as shipbuilding and marine plants, it is essential to prepare a way to enable organic working at the site referring to each other's detailed working data for collaboration between partner companies. However, companies cannot share the progress of the sites including working information in real-time due to the use of SW unique to each company and the complex site management system. As a result, the construction process is delayed, and resources are used inefficiently. This study developed a neutral data generation algorithm that can apply the working information in various file formats to a collaborative manufacturing process. In addition, this study verified the accuracy of the algorithm by applying the developed algorithm to the manufacturing process of piping in shipbuilding and marine plants, developing the SW for visualization of working information using the generated neutral data, and comparing the coordinate, shape & dimension and the kind, number, and spec. of BOM. The result confirmed that the accuracy of the coordinate of the neutral data was 99%, and that of the shape & dimension of the neutral data and BOM Spec. was both 100%. It is thought that this study can be used for overcoming the restrictions in information sharing due to the development of informatization at companies and maximizing the share of working file information in a complex manufacturing process.

• Journal of the Korean GEO-environmental Society
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• v.11 no.9
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• pp.15-25
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• 2010

The main objective of this study was to offer informations about long-term seepage behavioral characteristics and to find a leakage safety management method for Juam Dam and Imha Dam, a central cored rockfill dams in Korea by the evaluating the automatically monitored leakage data. In the water leakage monitoring of fill dam, the generation of abnormal water leakage is difficult to directly detect due to the effect of outside factors such as the component of rainfall inherent in the observation value. Therefore, conventionally estimation methods of water leakage quantity were applied by multiple regression analysis considering reservoir water level, rainfall, etc.. However, the estimated error of rainfall component is relatively big in these method. This paper identifies the seepage characteristic of each dams which is not directly affected by rainfall through the hydrograph separation analysis and 3 dimensional analytical method, and thinks a leakage management method. It was noticed that two dams had site specific seepage behaviour features and were in stable state with the decreasing leakage quantity. It was also found that hydrograph separation method might be applicable to leakage safety management method.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.5
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• pp.495-501
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• 2005

Al is a active metal that owes its resistance to a thin, protective, barrier oxide surface layer, which is stable in air and neutral aqueous solution. Thus Al alloys are widely used in architectural trim. cold & hot-water storage vessels and piping. However Al and most of its alloy may corrode with some forms such as pitting corrosion, intergranular corrosion and galvanic corrosion in the case of exposure to various industrial and marine atmosphere. Therefore a correct evaluation of corrosion resistance for their Al and Al alloys may be more important in a economical point of view. In this study. a relative evaluation of corrosion resistance for three kinds of Al alloys such as ALDC2, ALDC3, and ALDC8 series was carried out with electrochemical method. There is a tendency that corrosion potential is shifted to positive or negative direction by alloying components regardless of corrosion resistance. Moreover the data of corrosion properties obtained from cathodic Polarization curve, cyclic voltammogram and AC. DC impedance respectively showed a good correspondence each other against the corrosion resistance but variation of corrosion potential. passivity current density of anodic polarization curve and corrosion current density by Tafel extrapolation and Stern-Geary method didn't correspond with not only each other but also considerably the data of corrosion properties discussed above. Therefore it is suggested that an optimum electrochemical evaluation for corrosion resistance of Al alloy is to calculate the diffusion limiting current density of cathodic polarization curve, impedance of AC or DC and polarization resistance of cyclic voltammogram.

• Journal of Korea Water Resources Association
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• v.47 no.4
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• pp.307-319
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• 2014

Because of the rapid rising of water related disasters due to the global warming, the extreme design criteria of levee construction for severe flood has been applied in several developed countries such as USA and Netheland. In Korea, the national river restoration projects were carried out on 4 major rivers in recent several years. The projects consisted of riverbed dredge and levee reinforcement, and new construction have caused wide change of river environment. However, concrete countermeasures for levee safety and river management have not been suggested until now. Therefore, this study assesses the levee safety of Yulji levee located in Hoechon, Nakdong Basin, where the Levee Seepage Monitoring System installed. The stability of levee is assessed based on the simulation performed by SEEP/W(2D unsaturated seepage model) and the simulated results are compared with the observed data. The effects of the flood wave and levee shape on the levee safety are investigated through several simulations.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.1
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• pp.63-68
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• 2013

Some essential components in nuclear power plants are periodically inspected using non-destructive examinations, for example ultrasonic, eddy current and radiographic examinations, in order to determine their integrity. These components include nuclear power plant items such as vessels, containments, piping systems, pumps, valves, tubes and core support structure. Steam generator tubes have an important safety role because they constitute one of the primary barriers between the radioactive and non-radioactive sides of the nuclear power plant. There is potential that if a tube bursts while a plant is operating, radioactivity from the primary coolant system could escape directly to the atmosphere. Therefore, in-service inspections are critical in maintaining steam generator tube integrity. In general, the eddy current testing is widely used for the inspection of steam generator tubes due to its high inspection speed and flaw detectability on non-magnetic tubes. However, it is not easy to analyze correctly eddy current signals because they are influenced by many factors. Therefore, the performance of eddy current data analysts for steam generator tubing should be demonstrated comprehensively. In Korea, the performance of steam generator tubing analysts has been demonstrated using the Qualified Data Analyst program. This paper describes the performance demonstration program for steam generator tubing analysts and its implementation results in Korea. The pass rate of domestic analysts for this program was 71.4%.