• Structural Engineering and Mechanics
• /
• v.40 no.2
• /
• pp.257-277
• /
• 2011

In this paper the geometrically nonlinear continuum plate finite element model, hitherto not reported in the literature, is developed using the total Lagrange formulation. With the layerwise displacement field of Reddy, nonlinear Green-Lagrange small strain large displacements relations (in the von Karman sense) and linear elastic orthotropic material properties for each lamina, the 3D elasticity equations are reduced to 2D problem and the nonlinear equilibrium integral form is obtained. By performing the linearization on nonlinear integral form and then the discretization on linearized integral form, tangent stiffness matrix is obtained with less manipulation and in more consistent form, compared to the one obtained using laminated element approach. Symmetric tangent stiffness matrixes, together with internal force vector are then utilized in Newton Raphson's method for the numerical solution of nonlinear incremental finite element equilibrium equations. Despite of its complex layer dependent numerical nature, the present model has no shear locking problems, compared to ESL (Equivalent Single Layer) models, or aspect ratio problems, as the 3D finite element may have when analyzing thin plate behavior. The originally coded MATLAB computer program for the finite element solution is used to verify the accuracy of the numerical model, by calculating nonlinear response of plates with different mechanical properties, which are isotropic, orthotropic and anisotropic (cross ply and angle ply), different plate thickness, different boundary conditions and different load direction (unloading/loading). The obtained results are compared with available results from the literature and the linear solutions from the author's previous papers.

• Journal of the Korean Geographical Society
• /
• v.51 no.1
• /
• pp.89-108
• /
• 2016

This paper aims to illustrate how the third generation bike sharing schemes (BSS) are operated in Korea and identify the possible factors that have made cities to adopt and maintain BSS successfully in Korea. For this, the paper selects the case of Nubija in Changwon as the representative and the most successful BSS case in Korea. It identifies three major factors that have made the city to adopt Nubija. First, Nubija was initiated as a part of the bigger project of 'Environmental Capital' aiming to develop the city as a world class green city attempted by the city government. Second, the mayor's willingness to learn and adopt European model cities of environmental capital and green transportation played a decisive role in developing Nubija. Third, the city government was able to implement BSS policy in a top-down manner so the policy process was relatively speedy and effective. Also Nubijia became a stable policy because the city has gained international reputation as a Korea's representative green city, and as a result, the city's BSS policy has passed the point of no return. In the future, channels should be made for active citizen participation in the decision making process of Nubija so that they can cooperate with the city government to develop Nubija further.

• Composites Research
• /
• v.20 no.1
• /
• pp.23-31
• /
• 2007

In order to improve the mechanical properties of jute fiber/polypropylene(PP) composites, the property change with the addition of a coupling agent, maleic anhydride polypropylene(MAPP) was examined experimentally. The maleated coupler acts as an intermediate to chemically connect the polar nature of the fiber and non-polar nature of the polyolefin polymer resin. Furthermore, the decrease in viscosity of the resin which results from the melting point reduction by the MAPP, leads to an increase of contact area with the fiber interface. We discussed the improvement of the PP composite blend of the maleated coupler with the 80mm jute long fiber mat in conjunction with the change of physical parameters in the thermoplastic resin. We confirmed the extent of contribution to the mechanical physical enhancement by using the following parameters: melting flow index(MI) and viscosity, contact angle, thickness of the composite, interfacial shear strength and morphology observation etc. Especially it was observed that the MI and viscosity, MAPP mixture had a very strong relationship with the tensile and flexural strength and modulus, and interfacial shear strength(IFSS).

• Economic and Environmental Geology
• /
• v.14 no.3
• /
• pp.123-142
• /
• 1981

Granitic complex in the Woosanbong area is composed of schistose granite, two-mica granite, biotite granite, porphyritic granite and pink feldspar granite in order of intrusion. In their boundary aspects, the gradational change between porphyritic granite and pink feldspar granite is observed in field relations. All the granites of the complex are classified to quartz monzonite by the modal compositions following Bateman's classification (1961) with the exception of pink feldspar granite which belongs to granite according to the petrographical classification. The first three granites are characterized by highly development of vein and/or lens-like pegmatites in their bodies, and two others contain green hornblende uniquely. These leucocratic two-mica granite shows an unusual character in ratio of muscovite to biotite 1: 0.7 to 1:13, and contains dominantly microcline. The content of muscovite varies in places in the field. Under the polarizing microscope it is revealed that the muscovite flakes occur as the products altered from biotite partly or completely, and it usually associates with chlorite flakes nearby. These features, therefore, suggests that biotite probably has been altered to muscovite and chlorite by hydration during deuteric processes. At the same stage, sericitization of plagioclase by the hydrolytic decomposition, and transformation of orthoclase to microcline may be taken place. Accordingly, it is obviously permissible to consider the two-mica granite as a kind of 'apo-granite' by deuteric alterations during the consolidation of magma.

• Journal of Urban Science
• /
• v.9 no.1
• /
• pp.17-31
• /
• 2020

This study aims to analyze the relations among greenbelt, urban land surface temperature empirically in order to assess the environmental effects of the greenbelt in the Seoul metropolitan area, objectively. For this purpose, this study conducts an empirical analysis of impacts of greenbelt on urban land surface temperature using a multiple-regression model. The main data employed in the analysis include real-time air pollution data, Landsat 8-OLI Landsat imagery data, KLIS data and Jip-gye-gu data. The major findings are summarized as follows. NDVI has a negative (-) correlation with the land surface temperature, and the urban temperature is high in areas with poor vegetation. The land surface temperature is low in residential or commercial areas, while the temperature is high in industrial areas. The temperature is low in green fields, open spaces, and river areas. it is found that the urban land surface temperature is low in the greenbelt zone. In the greenbelt zone, there is an effect that reduces the land surface temperature by 1% on average, as compared to that at the center of the Seoul metropolitan area. Especially, the center of the Seoul metropolitan area, in a range from 0.6% to 1.9% of the average temperature, the temperature gets lower up to approximately 3km from the greenbelt boundary.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.24 no.4
• /
• pp.9-18
• /
• 1987

The hydrodynamic radiation forces acting on a ship travelling in waves have been conventionally treated by strip theories or by direct three dimensional approaches, most of which have been formulated in frequency domain. If the forward speed of a ship varies with time, or if its path is not a straight line, conventional frequency domain analysis can no more be used, and for these cases time domain analysis may be used. In this paper, formulations are made in time domain with applications to some problems the results of which are known in frequency domain. And the results of both domains are compared to show the characteristics and validity of time domain solutions. The radiation forces acting on a three dimensional body within the framework of a linear theory. If the linearity of entire system is assumed, radiation forces due to arbitrary ship motions can be expressed by the convolution integral of the arbitrary motion velocity and the so called impulse response function. Numerical calculations are done for some bodies of simple shapes and Series-60[$C_B=0.7$] ship model. For all cases, integral equation techniques with transient Green's function are used, and velocity or acceleration potentials are obtained as the solution of the integral equations. In liner systems, time domain solutions are related with frequency domain solutions by Fourier transform. Therefore time domain solutions are Fourier transformed by suitable relations and the results are compared with various frequency domain solutions, which show good agreements.

• Journal of Urban Science
• /
• v.9 no.2
• /
• pp.31-44
• /
• 2020

This study aims to analyze the relations among greenbelt, air pollution empirically in order to assess the environmental effects of the greenbelt in the Seoul metropolitan area, objectively. For this purpose, this study conducts an empirical analysis of impacts of greenbelt on urban air pollution using a multiple-regression model. The major findings are summarized as follows. As a result of an empirical analysis of the impacts of greenbelt on air pollution, it is found that the characteristics of the city have impacts on air pollution concentration. It is found that the population and employment are the causes of increases in CO and NO2 concentrations, and the number of employees in the manufacturers has impacts on increases of O3 and SO2, while power plants have impacts on PM10, CO and NO2. Intersections have impacts on O3 and SO2, while the areas of the roads have impacts on CO and NO2. In addition, as for the spatial distribution of air pollutants, it is found that CO and NO2 concentrations are relatively higher in the center of the Seoul metropolitan area, while PM10, O3 and SO2 concentrations are relatively higher in the suburbs. It is found that air pollution concentration is low in greenbelt zone. In the greenbelt zone, PM10, CO and SO2 concentrations are low.

• Nuclear Engineering and Technology
• /
• v.55 no.2
• /
• pp.587-594
• /
• 2023

This study investigates the impacts of nuclear energy consumption on environmental quality from a different perspective by focusing on carbon dioxide (CO2) emissions, ecological footprint, and load capacity factor. In this context, the South Korea case, which is a leading country producing and consuming nuclear energy, is investigated by considering also economic growth, and the 1997 Asian crisis from 1977 to 2018. To this end, the study employs the autoregressive distributed lag (ARDL) approach. Different from previous literature, this study proposes a load capacity curve (LCC) and tests the LCC and environmental Kuznets curve (EKC) hypotheses simultaneously. The analysis results reveal that (i) the LCC and EKC hypotheses are valid in South Korea; (ii) nuclear energy has an improving effect on the environmental quality; (iii) renewable energy does not have a significant long-term impact on the environment; (iv) the 1997 Asian crisis had an increasing effect on the load capacity factor; (v) South Korea has not yet reached the turning point, identified as $55,411, where per capita income improves environmental quality. Overall, the results show the validity of the LCC and EKC hypotheses and prove the positive contribution of nuclear energy to South Korea's green development strategies.

• Journal of Wetlands Research
• /
• v.21 no.1
• /
• pp.27-33
• /
• 2019

The future water management needs decentralization of facilities, diversity of technology and integration of management to overcome the waste of financial resources and increase in scale of facilities that occurred from centralized water management. In addition, citizen's environmental awareness and participation is important because all infrastructure installed in the watershed where citizens live should have the function of water management. Therefore, the research was performed by investigating the citizen's recognition about urban environment와 LID application to analyze citizen's perceptions and analyze the feasibility and possibility of LID application. The LID awareness of citizens was about 59%, but only about 46% of citizens agreed on the extension of application. However, after contacting LID photographs and information, 90% of respondents agreed on the application of LID, and 94% of respondents were able to distinguish between grey infrastructure and LID infrastructure. Citizens appeared to have a tendency to recognize green spaces as multi-functional LID infrastructure or green infrastructure. If citizens recognize multi-functional LIDs only as landscapjng area, it will be very difficult to extend the LID on the city areas. Therefore, for the extended application of the LID facilities, it is necessary to use public relations strategy to utilize the results and visual data on the actual effect verification. In addition, as every social infrastructure is formed in watershed where citizens live, it is necessary to plan and manage the infrastructure through governance with citizen participation.

• Journal of the Korean Society of Costume
• /
• v.20
• /
• pp.31-47
• /
• 1993

1. The relationship between Korea and Buk-Song had maintained for 164 years(964 1126 A.D). The period of relationship was from KwangJong Year 13(4years after establishing Buk-Song), Song Tae-Cho 1 year, to HeumJong Cheong Dang 1st year(InJong 4years in Koran). Author divides into three periodic terms, and remarkable diplomatic facts are as follows. 1) KwangJong year 13(963 A.D) SungJong year 13(994 A.D) : Normal relations, Song needed Korea's armed support. 2) MokJong year 6(1003 A.D) HyunJong year 9(1018 A.D) : Not steady relations and broke up, by MunJong year 26, Dang requested to resume the diplomatic relations. 3) MunJong year 25(1017 A.D) InJong 4(1126 A.D) : Song utilized Korea as a back supporter, but Song destructed by Keum. 2. Korea was donated knightage without offcial clothing by BukSong 10 times(KwangJong year 13 SungJong year 11). However during 164 years. Song presented some clothings Korea friendly. 3. Even though Korea cound not continue the steady diplomatic relations, Korea had been influenced the social systems including cloth-ing systems by Dang. Song dynasty. 4. The author studys historical materials which show that TongilSh-Shinra adapted social systems of Dang dynasty including clothing systems, which was succeeded to Korea for 200 years. Details are as follows ; 1) Original clothing color-systems which were Ja(purpil), Cheong(blue), Hwang(yellow), Pi, called 4-clored-system, of Tongil-Shinra, was suceeded to Korea, Above mentioned clothing systems of three countries of Korean peninsula. 2) When Korea unified the certificate of Pisam holders were superior from those of Tongil-Shinra and Hoo-Bakjae. There two classes used same seried-color 'ja, (Dan, Pi), Cheong(blue), Hwang(yellow)', or 'ja, (Dan, Pi), Cheong' and lasted to KwangJong year10 as a of-ficial clothing. 3) KwangJong year 7, according to the three colored official clothing system of Hooju, accepted Hooju's KwangJong year 11, that shifted 'Ja, (Dan, Pi), Cheong, Hwang', or, Ja, (Dan, Pi) Cheong', to 'Ja, Dan, Pi, Rok(green)'. 4) The clothing systems which are ja, (Dan, Pi), Rok which established KwangJong year 11 shifted to Song's, Ja, Ju(orange), Rok, Cheong, which had happened SungJong year 14 to MokJong 1st year. 5) 4-colored systems ('Ja, Pi, Rok, Cheong (distictable : sky blue, ocean blue)' shifted to 3 colored system which established Song ShingJong 1st year, which succeeded to Nam-Song and Keum. 5. The relationship between Korea and Yo had maintained for 207 years(918 1125 A.D). The period of relationship was from TaeJo 1st year to InJong year 3. 6. Yo, and Korea were called for king(15 times), prince(7 times). 7. Korea was donated knightage by Yo. The time when HyunJong year 13, Yo donated official clothing. From that time had used to do. The author divides into three periodic terms and discrives the shifting the formal clothing systems. Details were as follows ; 1) HyunJong year 13 MunJong year 8 : Even donating clothing systems from Yo had maintained for 35 years, Yeo, Song, Yo, three countries had not have formal cloth-ing, because they had been on the strug-gling. So that Korea had followed the same way of informal clothing. 2) MunJong year 918 : Yo donated the formal clothing to Korea for the King. Diplomatic condition was in the control, so that whole three countries used formal clothing. 3) MunJong year 19 YeaJong year 3 : Korea was donated 'Kuryumyun Kujangbokje', which became the formal clothings vs China.