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In this paper, we analyze the relationship between the characteristics of transportation energy consumption and urban form elements that were actively argued along with Environmentally Sound and Sustainable Development (ESSD). This paper can be divided into two parts: an examination of the theories and a practical analysis of domestic, small-, and medium-sized cities. Firstly, in the examination of theories, we surveyed the arguments about the sustainable urban form. Secondly, we made some hypotheses about the relationships between transportation energy consumption, city size, density, and center distribution pattern. Thirdly, we tested those hypotheses and examined the suitability of policies for each alternative for small-and medium-sized cities in Korea. The main themes in this paper are as follows. Firstly, how does the city size, density, etc. affect the transportation energy consumption? Secondly, in an overcrowded Korean situation, which alternative is the more suitable sustainable urban form from the point of transportation energy consumption, i.e., concentration or decentralized concentration? Thirdly, we examined the argument that a densely centralized development can reduce the need for travel, increase the transit use, and decrease automobile use. From the results of the analysis, we found that as the population increases, transportation energy represented by yearly gasoline consumption per automobile and the average yearly energy consumption as a result of surface transportation per 1,000 persons tends to decrease. Further, if the degree of city's concentration represented by Gini coefficient is high, energy efficiency tends to decrease. Besides, the influential factors on the transportation energy consumption among the indicators of urban form could be road ratio and density. Whereas the road ratio is not related to the transportation energy consumption, road density is. From the analyzed results, we can deduce planning implications concerned with Korean cities. Firstly, Korean cities are already highly centralized so a decentralization policy should be carried out to increase transportation energy efficiency. In any case, in the case of high-density cities, multinuclei cities are better than mononuclear ones. Further, to increase the transportation energy efficiency, policies for high road densities through the construction of new roads in spite of narrow road widths are more effective than those for high road ratio-widening existing roads.

In an effort to reduce the weight of vehicles, automotive companies are replacing conventional steel parts with light weight alloys and/or with advanced high strength steels (AHSS) such as dual-phase (DP), twinning induced plasticity (TWIP), and transformation induced plasticity (TRIP) steels. The main objective of this work is to experimentally and numerically evaluate the macro-performance of the automotive TWIP sheet in conjunction with springback. In order to characterize the mechanical properties, simple tension and tensioncompression tests were performed to determine anisotropic properties, as well as the Bauschinger, transient, and permanent softening behaviors during reverse loading. For numerical simulations, the anisotropic yield function Yld2000-2d was utilized along with the combined isotropic-kinematic hardening law based on the modified Chaboche model. Springback verification was performed for the unconstrained cylindrical bending and 2D draw bending tests.

Combustion characteristics such as combustion performance and combustion stability have been studied experimentally using a small liquid rocket thrust chamber with 19 liquid-liquid swirl coaxial injectors. Data were obtained from static pressure, temperature, and dynamic pressure sensors installed in propellant manifolds and the combustion chamber. While changing the recess length of the injector, characteristic velocity and pressure fluctuation data were collected and analyzed. In addition, chamber pressure was varied between 42 and 54 bar, which covers the sub-and supercritical pressures of oxygen. The results show that the longer recess length generally promotes combustion performance and the spray interaction between injectors in the multielement combustor increases the characteristic velocity. When the chamber pressure is above the critical pressure of oxygen, the recess length scarcely affects the pressure fluctuation. However, when the chamber pressure is below the critical pressure, the shift from external mixing to internal mixing of oxidizer and fuel sheets by the variation of recess length significantly degrades combustion stability and induces strong low-frequency instability. Accordingly, the effects of both recess length and operating chamber pressure must be taken into consideration when designing liquid-liquid swirl coaxial injectors.