• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.3B
• /
• pp.153-159
• /
• 2012

In this study, we proposed modified settling basins transformed by substituting the downstream sill for low head weirs such as generic labyrinth weir and inclined crest labyrinth weir worked as internal baffles. Laboratory experiments were carried out to understand hydraulic characteristics inside of the settling basin to improve the efficiency of sedimentation rate. For a quantitative analysis, we suggested the headwater ratio($H_t/P$), the magnification ratio(L/W) and the inflow rate per total crest length($q_L$) as primary analysis indexes for sedimentation efficiency. Six different types of settling basin were used for labscaled pilot tests by distinguishing with internal structures. Based on results, the variation of headwater ratio with the change of magnification ratio would highly affect the deposition efficiency(%) and it was improved under specific condition that repeating arrange number(N) of labyrinth weir was between 2 and 4. Also, the regression analysis showed that initial condition and shape for improving sedimentation efficiency were plotted on the graph for both $q_L{\geq}3.5cm^2/s$ and $L/W{\leq}3.5$. It would be expected that the geometrically optimized labyrinth settling basin could be designed with proper deposition efficiency for inflow rates of influent and required area of settling basin utilizing the proposed analysis index in this study.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.3
• /
• pp.407-417
• /
• 2011

Nowadays, the high land use, mainly used for urbanization, is affecting runoff loads of non-point pollutants to increase. According to this fact, increasing runoff loads seems like to appear that it contributes to high ratio of pollution loads in the whole the pollution loads and that this non-point source is the main cause of water becoming worse quality. Especially, concentrated pollutants on the impermeable roads run off to the public water bodies. Also the coefficient of runoff from roads is high with a fast velocity of runoff, which ends up with consequence that a lot of pollutants runoff happens when it is raining. Therefore it is very important project to evaluate the quantity of pollutant loads. In this study, I computed the pollutant loadings depending on time and rainfall to analyze characteristics of runoff while first flush storm water and evaluated the runoff time while first flush storm water and rainfall based on the change in curves on the graph. I also computed contribution ratio to identify its impact on water quality of stream. I realized that the management and treatment of first flush storm water effluents is very important for the management of road's non-point source pollutants because runoff loads of non-point source pollution are over the 80% of whole loads of stream. Also according to the evaluation of runoff loads of first flush storm water for SS, run off time was shown under the 30 minute and rainfall was shown under the 5mm which is less than 20% of whole rainfall. These are under 5mm which is regarded amount of first flush storm water by the Ministry of Environment and it is judged to be because run off by rainfall is very fast on impermeable roads. Also, run off time and rainfall of BOD is higher than SS. Therefore I realized that the management of non-point source should be managed and done differently depending on each material. Finally, the contribution ratio of pollutants loads by rainfall-runoff was shown SS 12.7%, BOD 12.7%, COD 15.9%, T-N 4.9%, T-P 8.9%, however, the pollutants loads flowing into the steam was shown 4.4%. This represents that the concentration of non-point pollutants is relatively higher and we should find the methodical management and should be concerned about non-point source for improvement on water quality of streams.

• Journal of the Ergonomics Society of Korea
• /
• v.4 no.1
• /
• pp.17-25
• /
• 1985

To evaluate the values of Aerobic on Deong-Deokoong Gymnastic that is variated Korean folk dance, 9 college women (from Soph. to Junior) who learned Korean Dance for 2 hours by week were volunteered as subjects from Sept. 1st to Nov. 3rd, 1984. Heart- rate of Deong-Deokoong Gymnastic performances recorded by 8 channel poly-graph system. 1. Critical values of Heart Rate in healthy college women is 142.54 bpm (mean). 2. Mean H.R. of Deong-Deokoong the 1st is $166.5{\pm}13.19bpm$, the 2nd is $164.06{\pm}13.93bpm$, the 3rd is $145.89{\pm}18.81bpm$, and the 4th is $151.5{\pm}16.7bpm$. 3. The ratio (%) of exercise H.R. by that of Maximum in Deong-Deokoong the 1st is $82.27{\pm}9.78%$, the 2nd is $79.91{\pm}8.65%$, the 3rd is $76.13{\pm}8.65%$, the 3rd is $76.13{\pm}9.15%$, and the 4th is $76.18{\pm}9.41%$. 4. Deong-Deokoong Gymnastic has the optimum load intensity as on aerobic function training program.

• Korean Journal of Poultry Science
• /
• v.16 no.4
• /
• pp.201-207
• /
• 1989

This study was carried out to identify the chromosome morphological structure and G-, C-banding pattern of Korean native fowl. The samples used in this study were early chick embryos, and the method of chromosomal analysis quoted from the protocal of Ohio univ. with more or less modified. The results were summerized as follow as； 1. In each of macrochromosomal morphology, the arm-ratio, centromeric index, and relative length of Korean native fowl were more or less different from improved breeds, but the designations were the same. 2. The graphical pecks, by densitometric recordings, in each macrochromosome number of 1, 2, 3, 4, Z, and 5, numbered 21, 14, 12, 8, 11, and 4 in G-banded, and 16, 13, 9, 9, 9, and 4 in C-banded, respectively. Those pecks could be explained as a consequence of chromosome condensation during mitosis and of genetic material differences.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.11
• /
• pp.92-97
• /
• 2010

The object of this study is to investigate the definite method for pitting damaged surfaces. Pitting is a sort of fatigue damages and it is made by a repetitive load. For a judgment between damages or not, sensing vibrations of test equipment is simple. However, it is not only difficult to observe a growth of pitting but also impossible to detect the juncture of initial pitting. Therefore, a method for the pitting damaged area measuring technique was effectively implemented by Two Roller Machine. The change of surface damaged area was measured by an optical microscope in regular time and calculated by the use of dark and bright ratio of test specimens' pictures taken by optical microscope. In conclusion, S - N Curves gained by Failure rate - Cycle graph was led and the curves are able to be chosen as occasion demands for a failure area percentage.

• Progress in Medical Physics
• /
• v.6 no.2
• /
• pp.103-109
• /
• 1995

Power spectral analysis of spontaneous heart rate fluctuations were assessed by use of autooic blocking agents and changes in posture. The total power spectral range of interest is divided amongst the various experiments so that each respiratory pattern contributes a spectral ratio of interval to respiration only over a group of frequencies for which the specific respiratory pattern has substantial, and roughly constant, spectral magnitudes. System hardware is consisted ECG preamplifier, respiratory fluctuation detect, interval time generator and IBC 486PC. High frequency fluctuation, at the respiratiory frequency, are decreased by standing and are mediated solely by the parasympathetic system. Power spectral analysis is a powerful nonivsve tool for quantitying autonomic nervous system activity.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.9 no.3
• /
• pp.251-261
• /
• 2007

This study is to investigate the damage assessment of adjacent structures due to tunneling in urban environment. Model tests were carried out with two-story masonry building structures in various shapes and locations. The damage level of adjacent structures were very differently estimated in accordance with the shape ratio (L/h) of structures, construction stages, and various locations. The results of model tests were plotted on the damage level graphs in order to predict the direction of damage levels for the different types of structures (i.e. stiffness of structures, L/h). The progressive crack development mechanism at various construction stages was revealed through model tests and crack size indicated more conservative side of damage level on the damage level graph.

• Journal of Industrial Technology
• /
• v.24 no.A
• /
• pp.37-46
• /
• 2004

A performance analysis for newly being considered electric rail car office has been made in this study. The major purpose is to examine a proposed design in terms of its capacity and the proposed number of travels (82-84) per day. For this study we first examined the overall system configuration with detailed operational processes of cleaning and inspection. We then developed a simulation model using ARENA and designed input data from 12 selected factors and their interaction effects. A simulation run for each treatment combination of $L_{16}(2^{15})$ orthogonal array was run and 20 batch means were obtained. Through careful analyses of the results obtained, we drew a diversity of suggestions including the best factor level combination. Our confirmation experiments at the optimal level combination further validate the possibility of 82 runs and the consistency in the results.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.37 no.2
• /
• pp.12-16
• /
• 2000

The electrical characteristics of n-channel LDD structured poly-Si TFT's have been systematically investigated. It have been found that the LDD regions act as the effect of series resistance and reducing the electric field. Kink effect is disappeared and off current is greatly reduced, while on current is slightly reduced. On/off current ratio graph shows that LDD device's switching characteristic is better than that of conventional device. As a result of study, it is concluded that the effect of electric field's reduction is more dominant than that of series resistance.

• Korean Journal of Food Science and Technology
• /
• v.35 no.6
• /
• pp.1093-1097
• /
• 2003

The aim of this study was to investigate the benefits of storing grapes through precooling, which is easier and more economical than the existing methods of storage. According to the analysis on the weight loss ratio, which is considered an important indicator of grape storage, the time at which the grapes reached 7% weight loss was prolonged by 5 to 10 days by the precooling method. Moreover, the percentage of abnormality on the 31st day of storage was at most 25% less in the precooled grapes than in the non-precooled grapes. In addition, the total bacterial count and the hardness of the precooled grapes were superior to those of the non-precooled grapes. Therefore, the precooling process markedly improved the commercial value of grapes.