• Structural Engineering and Mechanics
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• v.48 no.4
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• pp.455-466
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• 2013

In recent years, many countries have added railway noise to the issues covered by noise regulations. It is known that the rail is the dominant source of rolling noise at frequency range of 500Hz-2000Hz for the conventional speeds (<160km/h). One of the effective ways to reduce noise from railway track is using a rail vibration absorber. To study the acoustic performance of rail absorber, the decay rates of vibration have long been used by researcher. In this paper, A FE model of a periodic supported rail with infinite element in ABAQUS is developed to study the acoustic performance of the rail absorber. To compute the decay rates, acceleration responses along the rail transferred to MATLAB to obtain response levels in frequency domain and then by processing the response levels, the decay rates obtained for each1/3octav band. Continous rail absorber is represented by a steel layer and an elastomer layer. The decay rates for conventional rail and rail with one-side absorber and also, the rail with two side absorber are obtained and compared. Then, to improve the system of rail absorber, a steel plate with elastomer layer is added to bottom of the rail foot. The vertical decay rate results show that the decay rate of rail vibration along the track is significantly increased around the tuned frequency of the absorber and thus the rail vibration energy is substantially reduced in the corresponding frequency region and also effective in rail noise reduction.

• International Journal of Concrete Structures and Materials
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• v.4 no.2
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• pp.89-96
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• 2010

This paper focuses on the effect of creep on the critical compressive strain (CCS) of concrete. The strain of concrete corresponding to the peak compressive stress is crucial in the selection of the ultimate yield strength of the reinforcing bar used in reinforced concrete columns. Among the various influencing factors, such as the creep, shrinkage, loading rate and confinement, the effect of creep and shrinkage is the most significant. So far, investigations into how these factors can affect the CCS of concrete have been rare. Therefore, to investigate the effect of creep and shrinkage on CCS, an experimental (part I) and a parametric study (part II) were conducted, as presented in these papers (part I considers creep effect, part II considers effect of creep and shrinkage). In part I, experiments pertaining to the loading age, loading rate, loading duration and loading and creep levels were conducted to study the effect of these variables on the CCS of concrete. It was found that the effects of the loading rate, loading age, and level and duration on the CCS of concrete were negligible. However, it is very important to consider the effect of creep.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1387-1393
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• 2002

The measurement of velocity and stain rate field has been conducted in opposed impinging jet combustion. When a smaller diameter (5mm) orifice of pre-chamber was used, previous studies had reported that the combustion phase showed a shift from weak turbulent combustion to moderate turbulent combustion in the modified Borghi Diagram. In the case with smaller orifice diameter (5mm), NOx emission was substantially reduced by a factor 1/2 while the combustion pressure remains at the same as that in the conventional combustion. Hence, in this study, the experiment setup using PIV technique was designed to identify the relation of the strain rate distribution and NOx reduction associated with moderate turbulent combustion. As a result, it was found that the highly strained pockets are widely distributed during the combustion in the middle of chamber when the orifice diameter is 5mm. And the corresponding PDF distribution of strain rates she was the smoothly distributed strain .ate within the range of ｜$\pm$1000｜ (1/sec) rather than a spike shape about zero point. This is the unique feature observed in the combustion with 5mm orifice diameter. Therefore, it can be concluded that the substantial NOx reduction in opposed impinging combustor is mainly attributed to the strain rate distribution within the range of ｜$\pm$1000｜resulting in the combustion phase shift to moderate turbulent combustion.

• Journal of Korea Technology Innovation Society
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• v.15 no.3
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• pp.700-721
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• 2012

This paper deals with methods for determining the reasonable royalty rates in the valuation of patents. To calculate the reliable reasonable royalty rate of a patent, we review pros and cons of the 25% rule royalty calculating method and the recent trend of this method. We also review the game theory of Nash Bargaining equation and review the Investment of Rate of Return Method according to the financial analysis. Next, we refer to the reasonable royalty damage cases among the recent patent infringement cases in USA and analyze the corresponding patents. We extract the patent indicators from the patent bibliographic information. Finally, we obtain a regression model for calculating a reasonable royalty rate using the patent indicators and the reasonable royalty rates in the recent patent infringement cases.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.3
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• pp.287-293
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• 2009

The study involved the measurement of flowrate and BOD in the Yeoju area and analyzed annual sewerage data by the I/I analysis technique which is common in Korea. The results of this study are as follows. The I/I for the Y-1 site before maintenance and after the completion of the whole process was reduced from 62% to 16.1% respectively with respect to maximum sewage flow per day. The average quality of water increased. The study measured the Y-2 site from a point of time corresponding to an 80% process rate and its I/I rate went up a little from 8.5% to 11.5%. At the Y-3 site, the I/I rate went up a little from 11% to 13.8%, while little change was noted in the average water quality. At the Y-4 site, the I/I rate was reduced from 43% to 16.9% and its average water quality went up. At the Y-5 site, the I/I quantity went up a little however its average water quality also went up largely. Therefore, it was concluded that the Y-5 site showed great improvement due to the sewer pipe maintenance.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.267-274
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• 2008

This study is about efficiency of pretreatment process and operating factor to membrane process at continuous coagulation/ultrafiltration process in water treatment. The capacity of pilot plant was $0.06{\beta}(C)/d$. The raw water used was from Nakdong stream which was characteristized by high organic matter and high turbidity. The result of the test was that coagulation is good process as to high removal rate to organic matter and turbidity but It caused problem to membrane pore blocking. This paper is to determine the membrane fouling potential under different membrane flux, backwash pressure and linear velocity. Backwash pressure and flux is important parameter on operation of membrane system. Those are directly affected on membrane system. When backwash pressure increased from 150 kPa to 200 kPa, the result showed that fouling (pressure increase rate) changed from 3.69 kPa/h to 0.93 kPa/h and the recovery rate changed from 90.7 % to 82.0 %. Linear velocity had slightly effect on fouling. Linear velocity increased from 0.2 m/s to 0.5 m/s, the corresponding pressure rate changed from 0.93 kPa/d to 0.77 kPa/d.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.181-189
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• 2014

PURPOSES : Ambiguous decision on whether rural or urban area for road design can increase the construction cost and restrict the land use of surrounding area. However, administrative classification on rural and urban area is not directly related to road design because of this classification is not based on the engineering viewpoint, so method which can explain the road design context is required. METHODS : Method which enables to identify the area for road design is suggested based on the deceleration expected to be experienced by drivers who use the road section concerned. Deceleration rate corresponding to the area such as rural or urban suggested in Road Design Guideline is used as the criteria to identify the area by comparing this value with the estimated deceleration rate at the road section concerned. Speed profile method is utilized to derive the deceleration rate, and speed estimation way for reflecting both road geometry and intersection is suggested using stopping sight distance concept. RESULTS : The procedure of the method application is suggested, and the design example utilizing the method is provided. CONCLUSIONS : The method is expected to be used to identify the area for road design with engineering viewpoint, and design consistency among the roads with similar driving environment can be made.

• Korean Journal of Veterinary Service
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• v.21 no.3
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• pp.255-260
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• 1998

Since bovine leukosis caused considerable economic loss to the dairy industry, seroepidemiologi-cal survey on bovine leukosis was carried out for the dairy herds in Kyunggi province. 1. When compared the results of immunodifussion test with those of enzyme-linked immunosorbent assay(ELISA) for 94 dairy herds sera, the relationship between the immunodifussion test and ELISA were showen high corresponding rate with sensitivity(97.5%) and specificity(92.6%). 2. In immunodiffusion test for bovine leukosis virus (BLV) antibody in 570 dairy cattle from 30 herds, mean positive rate for BLV antibody was 28.2%. The positive rate by districts were 16.5% in central, 35.4% in east, 17.3% in west, 29.1% in south, 31.6% in north, 43.7% in northeast. 3. When the results of serological studies was analyzed by age groups, the number of positive was increased gradually with the advanced in age of herds. The highest positive rate was found in the age over 6 years. 4. Of 30 dairy herds examined, 5 herds(16.7%) have no reactions against BLV antigen while 15 herds (50%) showed the range of 1∼5 positive cattle and 5 herds(16.7%), the rang of over 11 positive cattle.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.580-584
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• 2008

Second-order rate constants (kN) have been measured spectrophotometrically for reactions of Y-substituted phenyl benzoates (1a-h) with azide ion (N3) in 80 mol % H2O/20 mol % DMSO at 25.0 0.1 oC. The Brnsted-type plot for the azidolysis exhibits a downward curvature, i.e., the slope (b lg) changes from 0.97 to 0.20 as the basicity of the leaving group decreases. The pKao (defined as the pKa at the center of the Brnsted curvature) is 4.8, which is practically identical to the pKa of the conjugate acid of N3 ion (4.73). Hammett plots correlated with s o and s constants exhibit highly scattered points for the azidolysis. On the contrary, the corresponding Yukawa-Tsuno plot results in an excellent linear correlation with r = 2.45 and r = 0.40, indicating that the leaving group departs in the rate-determining step. The curved Brnsted-type plot has been interpreted as a change in the rate-determining step in a stepwise mechanism. The microscopic rate constants (k1 and k2/k1 ratio) have been calculated for the azidolysis and found to be consistent with the proposed mechanism.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1678-1681
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• 2004

The light-transmission technique has been applied to a slit rheometer for measuring red blood cell aggregation as well as blood viscosity over a range of shear rates. For measurement of blood viscosity and aggregation, instantaneous pressure and transmit-light intensity are measured with time. Using a precision pressure measurement, one can determine the shear stress and shear rate. In addition, a transmitted light through a blood sample indicates degree of RBC aggregation. With abruptly flowing with high shear rate, RBCs rapidly disaggregate and the intensity of the transmitted light becomes low. When continuously flowing with decreasing shear rate, RBCs tend to re-aggregate and the corresponding transmit-intensity gradually increases with time. The light intensity as a degree of RBC aggregation is plotted against shear rate and compared with blood viscosity. The advantages of this design are dual measurement at a time, simplicity, i.e., ease of operation and no moving parts, low cost, short operating time, and the disposable kit which is contacted with blood sample.