• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집A
• /
• pp.304-309
• /
• 2000

Strain gage method is used to evaluate the mode I dynamic stress intensity factor of marging steel(18Ni) and titanium alloy(Ti-6A1-4V). To decide the best strain gage position on specimen, static fracture toughness test was performed. Then instrumented charpy impact test and dynamic tensile test was performed by using strain gage method for evlauating dynamic stress intensity factor. Strain gage signals on the crack tip region are used to calculate the stress intensity factors. It is found that strain gage method is more useful than method by using load which is obtained from impact tup to assess dynamic characteristics such as dynamic stress intensity factor.

• 환경영향평가
• /
• 제7권2호
• /
• pp.113-125
• /
• 1998

The amount of mercury emitted from an incinerator depends on the properties of waste, combustion condition, and control devices. Mercury concentration in air proportionates to the increase of incinerator installation. The purpose of this study is to provide a method for determination of mercury emission factor which can predict the amount of mercury emitted from each incinerator specifically. Case study was performed for N municipal waste incinerator. Based on the method presented in this paper, we obtained mercury emission factor as 1.85~1.95 g Hg/t at N Municipal Waste Incinerator and this result was regarded as reasonable when compared with existing mercury emission factor in reference cases. Fluorescent lamps turned out to be the most important source(44.4%) of mercury in municipal waste and its amount will tend to increase, while batteries become less significant. In addition, medical waste is one of the major source of mercury.

• Structural Engineering and Mechanics
• /
• 제46권3호
• /
• pp.353-370
• /
• 2013

This paper presents a new method to study the impact factor of an old bridge based on the model updating technique. Using the genetic algorithm (GA) by minimizing an objective function of the residuals between the measured and predicted responses, the bridge and vehicle coupled vibration models were updated. Based on the displacement relationship and the interaction force relationship at the contact patches, the vehicle-bridge coupled system can be established by combining the equations of motion of both the bridge and vehicles. The simulated results show that the present method can simulate precisely the response of the tested bridge; compared with the other bridge codes, the impact factor specified by the bridge code of AASHTO (LRFD) is the most conservative one, and the value of Chinese highway bridge design code (CHBDC) is the lowest; for the large majority of old bridges whose road surface conditions have deteriorated, calculating the impact factor with the bridge codes cannot ensure the reliable results.

• 대한기계학회논문집
• /
• 제14권2호
• /
• pp.298-309
• /
• 1990

In this paper, a new method is suggested to analyze impulsive stresses at loading poing of concentrated impact load under certain impact conditions determined by impact velocity, stiffness of plate and mass of impact body, etc. The impulsive stresses are analyzed by using the three dimensional dynamic theory of elasticity so as to analytically clarify the generation phenomenon of cone crack at the impact fracture of fragile materials (to be discussed if the second paper). The Lagrange's plate theory and Hertz's law of contact theory are used for the analysis of impact load, and the approximate equation of impact load is suggested to analyze the impulsive stresses at the impact point to decide the ranage of impact load factor. When impact load factors are over and under 0.263, approximate equations are suggested to be F(t)=Aexp(-Bt)sinCt and F(t)=Aexp(-bt) {1-exp(Ct)} respectively. Also, the inverse Laplace transformation is done by using the F.F.T.(fast fourier transform) algorithm. And in order to clarity the validity of stress analysis method, experiments on strain fluctuation at impact point are performed on a supported square glass plate. Finally, these analytical results are shown to be in close agreement with experimental results.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1993년도 추계학술대회 논문집
• /
• pp.381-386
• /
• 1993

This paper describes the dynamic fracture behavior of brittle materials under impact loading by using INSAMCR program with instrumented charpy test machine. To calculate the Dynamic Stress Intensity Factor The finite element analysis methods program, INSAMCR, was used. Dynamic fracture characteristic was researched to verify a relationship between Dynamic Stress Intensity Factor and crack tip propagation velocity in WC-6%Co. The relationship between Dynamic Stress Intensity Factor and crack tip velocity revealed typical .GAMMA. shape. INSAMCR was run to verify experimental results in WC-6%Co and shows a good coincidence.

• 한국문헌정보학회지
• /
• 제44권2호
• /
• pp.357-379
• /
• 2010

인용문헌 분석을 과거 집단적 분석에서 탈피하여 개개 문헌이 갖는 행위를 시간축에 따른 영향력으로 해석하여 단순히 인용 회수가 아닌 인용 체인내에서 문헌의 영향력으로 해석하여 보았다. 영향력 지수는 직접 인용이 되거나 비록 직접 인용은 되지 않았더라도 특정 문헌을 인용한 문헌이 다시 다른 문헌에 의해 인용되어질 경우, 특정 문헌의 영향을 받았다는 체인 구조 내에서의 연결 효과를 설명하고 있다. 실험의 결과는 인용되지 않은 문헌의 grace period를 도입하여 문헌의 수명을 인용 관계 속에서 풀었고 이렇게 살아남아 영향력 지수가 높은 문헌을 하나의 데이터베이스로 서비스 할 경우, 학술지 시장의 활성화와 도서관재정의 압박을 풀 수 있을 것이란 예측을 내놓았다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.382-399
• /
• 2011

Impact factor of concrete and ballast track which has been used in Korea railway was applied to equation (1+0.513V/100) from AREA. As the use of this equation, overcapacity of track design might be occurred. Therefore, this study compared impact of ballast track (well, bad) and concrete track (sleeper embeded system, rail floating and sleeper floating) by field test to analyzing dynamic effect of track structure's characteristic and wheel load on service line. In addition, it suggested a method to generate reasonable track impact factor on each track type.

• 조명전기설비학회논문지
• /
• 제20권9호
• /
• pp.78-83
• /
• 2006

A new measure, the distributed generation impact factor (DGIF), is used for evaluating the impact of newly introduced distributed generators on a networked distribution or a transmission system. Distribution systems are normally operated in a radial structure. But the introduction of distributed generation needs load flow calculation to analyze the networked system. In the developed framework, the potential share of every generation bus in each line flow of a networked system can be directly evaluated. The developed index does not require the solution of power flow equations to evaluate the effect of the distributed generation. The main advantage of the developed method lies in its capability of considering simultaneous outputs of multiple generation sites.

• 아태비즈니스연구
• /
• 제6권2호
• /
• pp.63-79
• /
• 2015

The purpose of this study is to examine the effects of transformational leadership on job satisfaction and to examine the effects of transactional leadership on job satisfaction. This study tried to verify the facial feedback hypothesis in causal relations of charisma, intellectual stimulation, individualized consideration, contingent reward, management by exception, job satisfaction. The self-administerd survey was undertaken against 380 respondents who soldier working in Daegu. A total of 375 responses were collected. Excluding missing data, 337 usable data were used for analysis. Results of this study are as follows. First, it is found that charisma factor is positively impact on job satisfaction. Second, it is found that individualized consideration factor is positively impact on job satisfaction. Third, it is found that contingent reward factor is positively impact on job satisfaction. Fourth, it is found that management by exception is positively impact on job satisfaction. The theoretical implication and practical implication for the army and government are discussed. The limitations are also mentioned.

• Structural Engineering and Mechanics
• /
• 제59권2호
• /
• pp.277-290
• /
• 2016

This paper investigates the ground vibration induced by high-speed trains moving on multi-span continuous bridges. The dynamic impact factor of multi-span continuous bridges under trainloads was first determined in the parametric study, which shows that the dynamic impact factor will be large when the first bridge vertical natural frequency is equal to the trainload dominant frequencies, nV/D, where n is a positive integer, V is the train speed, and D is the train carriage interval. In addition, more continuous spans will produce smaller dynamic impact factors at this resonance condition. Based on the results of three-dimensional finite element analyses using the soil-structure interaction for realistic high-speed railway bridges, we suggest that the bridge span be set at 1.4 to 1.5 times the carriage interval for simply supported bridges. If not, the use of four or more-than-four-span continuous bridges is suggested to reduce the train-induced vibration. This study also indicates that the vibration in the train is major generated from the rail irregularities and that from the bridge deformation is not dominant.