• Proceedings of the KSR Conference
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• 2000.11a
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• pp.418-425
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• 2000

In this study, the evaluation for utilization of waste landfill was performed by field test to use waste landfill as construction site(Nangido in Seoul). The site where dynamic compaction test was carried out was divided by 4 yards. Yard 1, 2 were not eliminated widening of cover soil and Yard 3, 4 were eliminated it. Dynamic Compaction Pilot Test was carried out by the 15ton heavy tamper with drop height of 20m in Yard 1, 3 and with drop height of 15m in Yard 2, 4 We evaluated the compaction ability, optimum compaction number and noiseㆍvibration through field test, monitoring. To make use of waste landfill as a construction site, The dynamic compaction method is suitable for using in waste landfill as a construction site among the ground improvement methods.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.767-772
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• 1998

schumidt hammer and ultra-sonic method are commonly used for concrete compressive strength test in a construction field. At present, various kinds of equations for estimation of strength are present, which have been used in a construction field. The purpose of this study is to evaluate the correlation between estimation strength by presentation equations and destructive strength to test specimen, and find out which is a suitable equation for this construction site. In this study, a strength test was carried out destructive test by means of core sampling. Non destructive test was conducted Schumidt hammer and ultra-sonic method, the experimental parameter were concrete age, test method and strength level. It is demonstrated that the correlation behavior of concrete strength in this study good due to the performs analysis of correlation between core strength and nondestructive strength.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.47-54
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• 2003

As a tool for strain measurement to work with screw driven or hydraulic material test systems, in which mechanical vibration is inherent, SSDG (Speckle Strain/Displacement Gage), ESP (Electronic Speckle Photography) and its 3-dimension version SDSP are evaluated for the theory and practical appliance. Through tension test of steel strips, their validity and shortcomings are examined. As the results, it has been shown that, although SSDG and ESP provide direct measurement of in-plane strain in one direction, they are so sensitive to the out-plane displacement. On the other hand, SDSP which is aided with DIC (Digital Image Correlation) technique to trace the movement of the speckles provides not only in-plane 2-dimensional displacement field, but also out-of-plane displacement simultaneously. However, because the DIC is time-consuming, not automated yet and it needs post-processing to evaluate strain from the displacement field, SDSP appears to be not adequate as a real time sensor.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.97-105
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• 2005

In order to reduce the uncertainties and improve the air flow field, objective analysis using asynoptic observational data is chosen as a method that enhances the reality of meteorology. In surficial data and their numerical interpolation for improving the interpretation of meteorological components, objective analysis scheme should perform a smooth interpolation, detect and remove the bad data and carry out internal consistency analysis. For objective analysis technique which related to data reliability and error suppression, we carried out two quality control methods. In site quality control, asynoptic observational data at urban area revealed low representation by the complex terrain and buildings. In case of wind field, it was more effective than temperature field when it were interpolated near waterbody data. Many roads, buildings, subways, vehicles are bring about artificial heat which left out of consideration on the simulation of air flow field. Therefore, in temperature field, objective analysis for more effective result was obtained when surficial data were interpolated as many as possible using value quality control rather than the selection of representative site.

• Tribology and Lubricants
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• v.29 no.1
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• pp.39-45
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• 2013

Magnetorheological (MR) fluid belongs to the group of smart materials. In MR fluid, iron particles in base oil form chains in the direction of the applied magnetic field, thus resulting in a variation in the stiffness and damping characteristics of the fluid. Research is being carried out on controlling the stiffness and damping characteristics as well as the tribological characteristics of the MR fluid. In this study, the friction characteristics of MR fluid have been evaluated using three types of materials and magnetic fields of different strengths. The coefficients of friction of the three types of MR fluid are measured, and the relationship between the coefficient of friction and the strength of the applied magnetic field is obtained.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.96-101
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• 2008

Due to improve form accuracy and surface roughness of a aspheric lens core that is made of Ni, the study is carried out on localization about a Subminiature Optics of Proximity and Wide Field of View. The required form accuracy P-V $0.2{\mu}m$ and surface roughness is Ra 10 nm. The design of experiment(DOE) is adopted to find a optimal cutting conditions which are spindle speed, depth of cut, feedrate. Finally, the effects of this study are replacing importation and strengthening competitiveness through the localization of the Subminiature Optics of Proximity and Wide Field of View.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.9-17
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• 2002

This analysis is aimed to find out how the conditions of secondary air injection affects the residence time and the turbulence energy of flue gas and flow field in a small incinerator. A commercial code, PHOENICS, is used to simulate the flow field of an Incinerator. The computational grid system is constructed in a cartesian coordinate system In this numerical experiment, an independent numerical variable is the conditions of secondary air injection and dependants are the residence time of flue gas and the mean value of turbulence energy in a primary combustion chamber. The flow field and the distribution of turbulence energy are analysed to evaluate the residence time of flue gas and the turbulence energy The computational results say that the tangential injection of secondary air make the residence time much longer than the radial injection and that the radial injection of secondary make turbulence much stronger than the tangential injection.

• Journal of the Korean Society of Tobacco Science
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• v.19 no.1
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• pp.24-28
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• 1997

The field experiment for field desalinization by precultivation of orchard crops were carried out to evaluate relationship between the varieation of chlorine contents of soil and crop uptake in the upland diverted from paddy field. After harvest of grass crops, soil samples were taken for analysis of chlorine contents of soil layers. Regardless of kinds of grass crops cutivated, contents of soil chlorine were decreased comparing to non-crop plot. Chlorine content in plant harvested at just before the flowering stage was much higher than that of after flowering. Chlorine uptake and dry matter were increased in order of Italian ryegrass, Perennial ryegrass, and Sudan grass. Positive correlations were showed between chlorine uptake and dry matter. The content of soil chlorine decreased by higher yield of dry matter.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.459-462
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• 2008

The fact that the major cases of life casualties are from smoke in the fire accidents and the expected steep increase of skyscrapers, huge spaces, multiplexes and huge scaled underground spaces demand establishment of efficient smoke countermeasure. The architectural factors affecting the pressure field of building should be examined for the successful design and operation of smoke management system and the stack effect is one of the important factors. The field experiments on stack effect in stairwells of high-rise building with regard to open/close condition of door are carried out to evaluate the features of pressure applied to door between each compartments, i.e, stair, lobby and accommodation. The procedures and results of experiments are presented.

• Journal of Biosystems Engineering
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• v.24 no.6
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• pp.493-500
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• 1999

In 1990's, two types of land consolidation has been widely carried out to enforce competativeness of rice production in Korea. One is so called large-scale land consolidation for resizing paddy field and farm road, the other is general land consolidation for changing both size and shape of field, water channel and farm road. This study was conducted to evaluate how much effect on fm mechanization the land consolidation had. To evaluate the influence of the land consolidation, theoretical analysis and surveys were accomplished. Land consolidation was analyzed to increase field efficiency by 180 to 670% depending on the type of land consolidation and machine selection. Also, land consolidation brought increment of real working time ratio by reducing traveling time on farm road. Trends of large scale mechanization and increment of custom work were observed to be accelerated by land consolidation. It also gave effect on the pattern of machine troubles. Farmers were conscious of the influence of land consolidation on machine utilization, however, in plains level of satisfaction was shown to be low.