• Journal of Magnetics
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• 제21권3호
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• pp.437-441
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• 2016

Dipole model based analytical expression is proposed to estimate the length and depth of the rectangular defect on ferromagnetic pipe. Among the three leakage profiles of Magnetic Flux Leakage (MFL), radial and axial leakage profiles are considered in this work. Permeability variation of the specimen is ignored by considering the flux density as close to saturation level of the inspected specimen. Comparing the profile of both the components, radial leakage profile furnishes the better estimation of defect parameter. This is evident from the results of error percentage of length and depth of the defect. Normalized pattern of the proposed analytical model radial leakage profile is good agreement with the experimentally obtained profile support the performance of proposed expression.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1990년도 추계학술발표회논문집
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• pp.35-40
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• 1990

Temperature distribution of high pressure mercury lamp has been mesured as a function of time using spectroscopic method. Sampling signal which is synchronized by lamp voltage was used to mesure temporal line intensity at each radius. To obtain radial temprature distribution, the mesured intensity was transformed into radial line intensity by Abel's formula. Absolute temperature profile was calculater from relative intensities of spectral lines as a function of line and tube radius. The temperature profile is very similar to the electrical tube current profile.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 제7회 압연 심포지엄
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• pp.19-22
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• 2009

It is essential to predict the deformed roll profile for the prediction of the strip profile in rolling process. The work roll of the Sendzimir mill has a small diameter in comparison to a barrel length, so that it is well deformed by the rolling pressure. Also it has a complex roll system, so it is difficult to analyze the roll deflection. In this paper, 3D finite element method is used for the analysis of the roll deflection of the Sendzimir due to the contact between rolls. But it takes much time to get the results, so that the on-line model to evaluate the radial deformation of a roll is developed on the basis of the finite element method.

• 한국진공학회지
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• 제17권5호
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• pp.400-407
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• 2008

본 연구에서는 축전 결합형 플라즈마원에 대한 전자기장의 2차원 공간 의존성을 계산하였다. 1차원 유체 방정식을 기반으로 축전 전기장과 전도 전류 밀도의 axial 방향 공간 의존성을 계산한 후, radial 방향으로는 맥스웰 방정식의 해를 ${\omega}r/c$에 대한 power series로 전개하여 전자기장의 2차원 공간 의존성을 계산하였다.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1582-1589
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• 2016

In this paper the integration of Distributed Generation (DG) in radial distribution system is investigated by computing the optimal site and size of DG to be placed. An analytical expression based on equivalent current injection has been derived by utilizing topological structure of radial distribution system to find optimal size of DG to minimize losses. In the presented formulation, the optimal DG placement is obtained without repeatedly computing the load flow. The proposed formulation can be used to find the optimal size of all types of DGs namely Type-I, Type-II, Type-III and Type-IV DGs. The investigations are carried out on IEEE 33-bus and 69-bus radial distribution systems. The optimal DG placement results into reduction in active and reactive power losses and improvement in voltage profile of the buses.

• 태양에너지
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• 제2권1호
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• pp.24-32
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• 1982

In this paper, temperature distributions in radial fin of rectangular profile for steady-state with no heat generation are obtained by one-dimensional analytical method, finite difference method and experiment respectively. Heat flow rate and fin efficiency from the fin model are obtained by analytical method. Consequently, temperature distributions in radial fin can certify that are similar to exact solution. From theoretical analysis, the effects according to heat flow rate and fin efficiency are related to variation of parameters which are fin thickness ${\delta}_o$, fin base temperature $T_o$, thermal conductivity K with same basic dimensions and the effects are studied and compared.

• 대한설비공학회지:설비저널
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• 제11권3호
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• pp.9-17
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• 1982

In this paper, temperature distributions in radial fin of hyperbolic profile for steady -state with no heat generation are obtained by one-dimensional analytical method, finite difference method and experiment respectively. Heat flow rate and fin efficiency from the fin model are obtained by analytical method. To compare the exact solutions obtained by theoretical analysis with the results obtained by finite difference method, cylindrical shape is selected. Particularly, equations of finite difference method for cylindrical shape with irregular boundary are rearranged and formulated. Consequently, temperature distributions in radial fin can certify that are similar to exact solutions. From theoretical analysis, the effects according to heat flow rate and fin efficiency are related to variation of parameters which are fin thickness ${\delta}_o$, fin base temperature $T_o$, thermal conductivity K with same basic dimensions and the fleets are studied and compared.

• 대한기계학회논문집B
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• 제23권2호
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• pp.243-253
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• 1999

The dual reciprocity boundary element method (DRBEM) is used to solve the Graetz problem of laminar flow inside circular duct. In this method the domain integral tenn of boundary integral equation resulting from source term of governing equation is transformed into equivalent boundary-only integrals by using the radial basis interpolation function, and therefore complicate domain discretization procedure Is completely removed. Velocity profile is obtained by solving the momentum equation first and then, using this velocities as Input data, energy equation Is solved to get the temperature profile by advancing from duct entrance through the axial direction marching scheme. DRBEM solution is tested for the uniform temperature and heat flux boundary condition cases. Local Nusselt number, mixed mean temperature and temperature profile inside duct at each dimensionless axial location are obtained and compared with exact solutions for the accuracy test Solutions arc in good agreement at the entry region as well as fully developed region of circular duct, and their accuracy are verified from error analysis.

• 천문학회지
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• 제45권3호
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• pp.71-84
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• 2012

We present a photometric study of the globular clusters (GCs) in the Virgo giant elliptical galaxy M86 based on Washington $CT_1$ images. The colors of the GCs in M86 show a bimodal distribution with a blue peak at ($C-T_1$) = 1.30 and a red peak at ($C-T_1$) = 1.72. The spatial distribution of the red GCs is elongated similar to that of the stellar halo, while that of the blue GCs is roughly circular. The radial number density profile of the blue GCs is more extended than that of the red GCs. The radial number density profile of the red GCs is consistent with the surface brightness profile of the M86 stellar halo. The GC system has a negative radial color gradient, which is mainly due to the number ratio of the blue GCs to the red GCs increasing as galactocentric radius increases. The bright blue GCs in the outer region of M86 show a blue tilt: the brighter they are, the redder their mean colors get. These results are discussed in comparison with other Virgo giant elliptical galaxies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1009-1011
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• 1997

This paper presents an optimization method which determines locations and size of capacitors simultaneously while minimizing power losses and improving voltage profile in radial distribution systems. Especially, the cost function associated with capacitor placement is considered as step function due to banks of standard discrete capacities. Genetic algorithms(GA) are used to obtain efficiently the solution of the cost function associated with capacitors which is non-continuous and non-differentiable function. The strings in GA consist of the node number index and size of capacitors to be installed. The length mutation operator, which is able to change the length of strings in each generation, is used. The proposed method which determines locations and size of capacitors simultaneously can reduce power losses and improve' voltage profile with capacitors of minimum size. Its efficiency is proved through the application in radial distribution systems.