• Journal of the Korean Wood Science and Technology
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• v.40 no.5
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• pp.352-362
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• 2012

Mass transfer behavior in wood was estimated through its microscopic structure. The diffusion coefficients which were decided by theoretical equations are influenced by different anatomical properties of wood. From the experiment, the moisture flux was linear to the square root of time. The diffusion coefficients had a regular tendency during the time elapse. During the modeling, it is necessary to understand the limitation of parameters and consider the particular situation to be simulated. In hardwood, because the apertures were not considered, tangential mass transfer simulation was totally different from experiment. As a result, a hardwood model design should consider the apertures which are even on the fiber walls.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.5
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• pp.63-71
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• 2005

In-situ soil remediation mechanism through the vertical drains (VDs) is analyzed with numerical model as the error and complementary error function. Results from in-situ test and analysis indicate that the contaminant concentration ratio as initial one ( C/$C_0$) increases as the radius ratio ( r/R) increases from the injection well, and also increases as the depth ratio ( z/ H) increases from the top of contaminated area. The elapse time needed to attain $50\%$ and $90\%$ clean up level ($ t_{50},\;t_{90}$) increases as the radius ratio ( r/R) and the depth ratio ( z/ H) increase. As above results, the procedure of soil flushing in contaminated area using vertical drains makes progress from the top of injection well to the bottom of extraction well.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1741-1748
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• 1995

A new particle tracking algorithm using the concept of match probability between two consequent image frames has been developed to obtain an instantaneous 2-dimensional velocity field. A computer simulation has been carried out to check the performance and usefulness of the developed algorithm by comparing with the conventional 4-frame Particle Tracking Velocimetry(PTV) method. As a result the newly developed algorithm shows very good performance. Although the major part of the developed algorithm is time-consuming iterative updating routine of match probability, computational elapse time to get the resonable results is a very short compared with the 4-frame PTv.Additionally, the present 2-frame PTV algorithm recovers more velocity vectors and has higher dynamic range and lower error ratio compared with the conventional 4-frame PTV.

• Journal of the Korean Institute of Telematics and Electronics
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• v.10 no.5
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• pp.7-15
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• 1973

The gain stability of the nuclear pulse ampifiers with negative feedback for such a fast pulse input as the step voltge or the nuclear radiation detector pulse is analyzed in detail and the experimental results are given. It is shown that a few risetime should elapse to get the full effect of the negative feedback upon the liearity and the stability of the amplifiers for the fast pulse input, and to reduce this limitation the risetime of the negative feedback amplifier must be designed to be short compared with the width of the input pulse.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.237-245
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• 2005

In this paper, the changes of the period of cold weather concrete in Korea with the elapse of age are discussed to investigate the influence of elapse of age on period of cold weather concrete. The climate data of Korean Meteorological Administration(KMA) ranging from 1971 to 2000 was used. The period of cold weather concrete was calculated by following the specification of Korea Concrete Institute(KCI), American Concrete Institute(ACI) and Architectural Institute of Japan(AIJ), respectively. Previous research by the authors used the climate dada of KMA from 1961 to 1990 and research conducted by Kim M.H. used the climate data from 1931 to 1980 were also compared with the period of present paper. According to the results, in present paper, the period of cold weather concreting by KCI was calculated about 95days on average and the period by ACI was 101 days on average and the period by AIJI was 92days on average. For the variation of the period with the elapse of time, the period of cold weather concrete by KCI and ACI in present paper was shortened by as much as 5${\~}$6days compared with that of previous paper 10years ago. However, the period of cold weather concreting by AIJ did not exhibit a marked reduction in the period compared with that of previous paper by the author. But the period by Kim following AIJ exhibited a decrease in the period compared to the period by present paper by as much as 3days. For regional influence, the period of cold weather concreting in southern part of Korea was found to be much shorter than those at northern part. This may be due to the rising of mean temperature caused by global warming effect.

• KIEAE Journal
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• v.11 no.6
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• pp.13-18
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• 2011

Building is different from the general commodities and needs to maintain the function and performance to get the living condition. Building deterioration occurs naturally with time elapse. Deterioration reasons are various. These are physical, functional, social and second physical aspect. Building would inevitably be deteriorated and need to repair various building part and materials. It gets to arrive at repair or rebuilding time until any management activity is meaningless. It is important to decide the rebuilding time in a management cost. In this paper, it aimed at analyzing the management annual cost and provide a rebuilding time of a apartment housing with a deterioration curve model. Results of this study are as follows : Most of the building has started to deteriorate in 40 years when the performance of building downgrades to 20%. After it past about 40 years, the deterioration rate is faster than the earlier 40 years. Fourth, the rebuilding time of an apartment housing is recommended about 45 years if the building service life has 60 years.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.3
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• pp.135-143
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• 2009

To study the behavioral reaction of common squid Todarodes pacificus, to different colors of LED light, individual distribution in the dark condition without LED light stimuli, individual distribution when four colors of light stimuli were at the sections of end and middle of water tank and the changes of gathering rates as the elapse of illuminating time were examined. When it was dark, the distribution of the fish in each section of the tank was U-shape regardless of the investigating time intervals, which means that Todarodes pacificus gathered at the both ends of the tank. The individual distribution when light stimuli were at the one end of the tank showed the tendency of gathering at the illuminated section and decreasing at the opposite section. There were 448 of them at the end of the tank when the light was blue, 352 when white, 302 when green and 132 when red. Thus the fish liked blue light the most, followed by white light. The variations of gathering rate at the both ends of tank as illuminating time elapsed showed the tendency of increasing at the light section (A section), however, it showed the tendency of decreasing at the darkest section (F section). The individual distribution showed the tendency of letter $\wedge$ of gathering at the center and decreasing at the both ends mostly when the light stimuli were at the middle section of tank. The gathering rates at the lighting section were 80.4% when red, 76.4% when white, 69.6% when green and 56.7% when blue. The fishes showed the affinity for the red light mostly, followed by the white light source. The red light and blue light showed the opposite when the light stimuli were at the one end of water tank. The variations of gathering rates as the elapse of time at the lighted section showed the tendency of gradual increasing in the four light sources. The color of light source showing the highest gathering rate within 25-30 minutes of light stimuli was the white, followed by the red.

• Journal of the Korean housing association
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• v.17 no.5
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• pp.87-95
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• 2006

Building components have been deteriorated by various factors such as location, a building type, a surrounding environment and so on. In addition, each component has a peculiar characteristics, compared with other components in properties of matter an used part. Building components would be required to maintain its function and performance to provide the resident with a decent living condition. It is important to decide the repair time, scope and a required cost in repair plan, considering the each component's characteristics. In this parer, it aimed at providing the economic repair pattern to analyze the relation of the time-elapse and the cumulative repair cost in the apartment housing using 3rd quadratic function. Results of the study are as follows: First, the shape of the function for the economic repair is classified into two type. One is the continuous increase type of the cumulative cost which properly means the iterative repair type after built. The other is that the function has the maximum state at a point which means one-repair after its repair would be delayed to a scheduled time. Second, the iterative repair pattern would include window, roof proof, lighting and water supply pipe. The other repair pattern would include the paintings, heating pipe and sign board.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.73-79
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• 1997

This research was intended as an investigation of applying Reduced Pressure Evaporation as efficient treatment method for landfill leachate. According to the variance of time, temperature, pressure and pH in experiments, the properties of leachate treatment are follows. The removal efficiencies of COD, NH$_{3}$-N, TOC, Conductivity and SS on the basis of reaction time was 96.4%-97.5%, -1.4%-53.7%, 81.7%-89.0%, 92.0%-95.3% and 99.86%-99.97%, respectively. When the pH of Influent was 7.5, the pH of effluent was increased to 10-11 with time elapse. It is concluded that the orgin of pH increase may be ammonia. When the properties of concentrate were investigated at the concentration ratio 90%(V/V), concentration difficiency represented in the ratio of experimental value/calculated value had following orders ; COD>TOC>NH$_{3}$-N>Conductivity>SS. Concentrate had good precipitation because of additive thermal treatment in the process. When evaporation experiments with pH adjustment of 4.0, 6.0, 7.5, 9.0 and 10.0 were performed ; Acidic evaporation experiments(pH 4.0, 6.0) showed low removal efficiency(81.6, 87.6%) of COD and high removal efficiency (97.5%. 84.6%) of NH$_{3}$-N at initial evaporation. Basic evaporation(pH 9.0, 10.0) showed high removal efficiency (97.2%, 98.9%) of COD and very low removal efficiency (-7.4%, -27.2%) of NH$_{3}$-N at initial evaporation.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10a
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• pp.147-158
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• 2001

In general, two methods have been used to predict settlement of soft ground. One method is Terzaghi's one dimensional consolidation theory which gives time-settlement relationship using the standard consolidation test results. The other is forecasting method of ground settlement to be occured in the future using in-situ monitoring data. The above both methods have some defects in application manner or in itself especially in very deep and soft clayey ground. In view of the lessons and experiences of soft ground improvement projects, several techniques were proposed for more accurate theorectical calculation of consolidation settlement as follows ; ① Subdivision of soft ground, ② Consideration of secondary compression, ③ Using the modified compression index, etc. And also, revised hyperbolic fitting method was suggested to minimize the error of predicted future settlement. In addition, revised De-Beer equation of immediate settlement of loose sandy soil was proposed to overcome the tendency to show too small settlement calculation results by original De-Deer equation. And also, considering the various effects of settlement delay in the improved ground by vertical drains, time-settlement caculation equation(Onoue method) was revised to match the tendency of settlement delay by using the characteristics of discharge capacity decreases of vertical drain with time elapse by the pattern of hyperbolic equation.