• Geophysics and Geophysical Exploration
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• v.26 no.1
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• pp.1-7
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• 2023

This study derives the expressions of vector gravity and gravity gradient tensor due to an elliptical cylinder. The vector gravity for an arbitrary three-dimensional (3D) body is obtained by differentiating the gravitational potential, including the triple integral, according to the shape of the body in each axis direction. The vector gravity of the 3D body with axial symmetry is integrated along the axial direction and reduced to a double integral. The complex Green's theorem using complex conjugates subsequently converts the double integral into a one-dimensional (1D) closed-line integral. Finally, the vector gravity due to the elliptical cylinder is derived using 1D numerical integration by parameterizing a boundary of the elliptical cross-section as a closed line. Similarly, the gravity gradient tensor due to the elliptical cylinder is second-order differentiated from the gravitational potential, including the triple integral, and integrated along the vertical axis direction reducing it to a double integral. Consequently, all the components of the gravity gradient tensor due to an elliptical cylinder are derived using complex Green's theorem as used in the case of vector gravity.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.46.1-46.1
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• 2019

We present an accurate and efficient method to calculate the gravitational potential of an isolated system in three-dimensional Cartesian and cylindrical coordinates subject to vacuum (open) boundary conditions. Our method consists of two parts: an interior solver and a boundary solver. The interior solver adopts an eigenfunction expansion method together with a tridiagonal matrix solver to solve the Poisson equation subject to the zero boundary condition. The boundary solver employs James's method to calculate the boundary potential due to the screening charges required to keep the zero boundary condition for the interior solver. A full computation of gravitational potential requires running the interior solver twice and the boundary solver once. We develop a method to compute the discrete Green's function in cylindrical coordinates, which is an integral part of the James algorithm to maintain second-order accuracy. We implement our method in the {\tt Athena++} magnetohydrodynamics code, and perform various tests to check that our solver is second-order accurate and exhibits good parallel performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1204-1210
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• 2000

An analysis method for obtaining transient response of electromagnetic pulse(EMP) coupled via a slot aperture into a parallel-plate waveguide, is considered. The mixed-potential integral equation(MPIE), in which the vector and scalar potential Green's functions for the unknown equivalent magnetic surface current of the aperture in parallel-plate region are expressed in closed forms derived by use of the improved complex image method, is formulated. When the method of moments(MoM) is used to solve the MPIE, the matrix-fill time is significantly reduced because of closed-form Green's functions. In order to check the validity of the present method, the numerical results obtained by the present method are compared with those obtained by the previous method. Fairly good agreements between them are observed.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1910-1913
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• 2006

To solve the interaction of incident monochromatic waves with a bottom-fixed vertical circular cylinder, a numerical analysis by boundary element method is developed using three-dimensional linear potential theory. A numerical analysis by boundary element method is based on Green's theorem and introduce to an integral equation for the fluid velocity potential around the vertical circular cylinder. These numerical results are compared with those of ManCamy and Fuchs(1954) and Williams and Mansour(2002), and it has shown good relationship with their results. This numerical analysis developed by boundary element method will be applied for various offshore structures to be constructed in coastal zones in the future.

• Journal of Navigation and Port Research
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• v.32 no.7
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• pp.543-552
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• 2008

The diffraction of waves by three bottom fixed vertical circular cylinders is investigated by using the boundary element method. This method has been successfully applied to the isolated vertical circular cylinder and now is used to study the interaction between waves and multiple vertical cylinders. In this paper, a numerical analysis by the boundary element method is developed by the linear potential theory. The numerical analysis by the boundary element method is based on Green's second theorem and introduced to an integral equation for the fluid velocity potential around the vertical circular cylinders. To verify this method, the results obtained in present study are compared with the results computed by the multiple scattering method. The results of the comparisons show strong agreement. Also in this paper, several numerical examples are given to illustrate the effects of various parameters on the wave exciting force such are the separation distance, the wave number and the incident wave angle. This numerical computation method might be used broadly for the design of various offshore structures to be constructed in the future.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.241-241
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• 2010

Recently high and persistent spontaneous buildup of a surface potential (SP) upon vacuum deposition of tris (8-hydroxyquinolinato) aluminum (III) ($Alq_3$), which is widely used for organic light emitting devices. The removal of the giant surface potential by visible light irradiation has also been reported. In this study, we coated $Alq_3$ on the FTO substrate and raise the capacity for absorbing sun light. The $Alq_3$ which is green light emitting diode emits light at wavelengths between 500 and 550nm. If we apply one's FTO/$Alq_3$ substrate in one's DSSC, we could get higher energy conversion efficiency because the N719 dye that we used for fabricating the DSSC emits light just at near 540nm. The energy conversion efficiency of approximately 4.8 % at the condition of irradiation of AM 1.5 (100 mW/$cm^2$) simulated sunlight, and the $J_{sc}$ is 12.0 mA/$cm^2$, $V_{oc}$ is 0.71 V, FF is 0.56, respectively.

• Bulletin of the Society of Naval Architects of Korea
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• v.24 no.1
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• pp.1-8
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• 1987

It is shown that irregular frequencies in the source and doublet distribution method, can be eliminated if the Green function associated with Kelvin's source of pulsating strength, is modified only in the region inside the body at the level of the undisturbed free surface. The system of the resulting Green integral equation is augmented without loss of the square-integrable property of its kernel so hat the discretisation yield N linearly independent equations for N unknown variables. From the solution, the potential and velocity at any point on the wetted surface of a surface-piercing body can be found using the properties of the double layer composed of the source and normal doublet distribution.

• Bulletin of the Korea Photovoltaic Society
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• v.6 no.1
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• pp.76-85
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• 2020

The Republic of Kazakhstan is a geographically large but sparsely populated country, rich in natural resources, located in the center of the Eurasian continent. In recent years, it has begun to create a green economy, leading it among its neighbors in Central Asia. Therefore, the country has set a clear goal: by 2030, emissions should be reduced by 15-25% compared to the level of the 90s. As part of the country green economy strategy, in 2013 Kazakhstan adopted the "National Concept for the Transition to the Green Economy until 2050", which sets out the principles of the green economy as a path for future development. The goal is to bring the share of renewable energy in electricity production from zero to 3% by 2020, and then increase it to 30% by 2030 and 50% by 2050. This paper looks at what Kazakhstan has done to promote renewable energy and provider perspectives. The paper also considers Kazakhstani legislation in terms of the development of renewable energy sources and provides information on incentives and preferences for the development of renewable energy sources. Thus, it will be easier for investors to evaluate the implementation of potential projects in Kazakhstan.

• Journal of Korean Society of Rural Planning
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• v.22 no.1
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• pp.69-79
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• 2016

The purpose of this study is to draw implications and critical success factors by surveying and analysing practice cases of green care in south Korea. To achieve the object of this study, many valuable cases were checked through preceding researches and internet informations. Case study targets were divided into side-work farmer type, professional farmer type, and Institution directed type, and then case study surveys were performed by each type. Every case has the natural environment in common, and tries to satisfy users's demands and to give the opportunity to communicate. Especially, the strong motivation, mind, and entrepreneurship of operators are very important factors for green care. If the development of government supporting policies and related education programs are accompanied with lots of potential such as Korean oriental medicine, rural tourism village, and sixth industry project, it will be possible to introduce and manage green care successfully.

• East Asian Journal of Business Economics (EAJBE)
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• v.11 no.2
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• pp.29-38
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• 2023

Purpose - The current study aims to learn how fashion consumers now feel about environmental issues. The significance of "green fashion product creation" in resolving environmental issues is explored. It also examines how customers' environmental consciousness has evolved due to the introduction of green fashion products. Research design, data, and methodology - The study methods, procedures, and results of the 16 publications included in this literature review were critically examined. The data sources, analyses, and key findings presented in each publication were compared and contrasted. To better understand how to raise environmental consciousness among customers. Result - The investigation indicates a total of four results why eco-friendly product should be developed to attract potential green consumers. Four solutions are as follows; (1) Encourages Sustainable Consumption Behavior, (2) Increases Consumer Environmental Awareness, (3) Improves Corporate Social Responsibility, and (4) Enhances Competitive Advantage. Conclusion - Promoting sustainability in the fashion sector requires full visibility throughout the supply chain. Companies in the fashion industry would serve their customers better if they were more forthcoming about the resources, methods, and circumstances that went into making their wares. Consumers may accomplish this by including instructions on the packaging or posting them on the business's website.