The social dimension of urban design as a means of engendering community engagement in urban regeneration

PhD ThesisThe contribution to knowledge of this thesis is to suggest the potential of urban design through an integrated linkage between the social role of urban design and community engagement in urban regeneration as a response of the advocacy of participative urban design approach and the academic debate of community engagement. This thesis explores the social dimension of urban design in urban regeneration with the contexts of urban policies in England and South Korea. The thesis progresses a detailed empirical investigation of urban design in both countries’ urban regeneration practices, principally Scotswood and Walker Riverside in Newcastle upon Tyne, UK and Singil in Seoul, South Korea. It illustrates that urban design plays various roles in urban regeneration in physical and social aspects, concerning improving physical environments, local resident’s liveability, and tackling social problems. It also identifies challenges for urban design in urban regeneration in relation to various tensions in the practice of urban regeneration. How local communities are engaged in the wider process of urban regeneration practices is illustrated in this thesis. The exploration of urban regeneration practices explains the mechanisms for identifying community views in relation to urban design. It identifies factors affecting community engagement and channels for community engagement in the process of urban design in urban regeneration and underlines community engagement in the management of end-products of urban design. The thesis concludes with a discussion about the social dimension and the potentials of urban design in urban regeneration. It highlights that urban design plays a role in community engagement, as a means of engendering community engagement in urban regeneration. It discusses the potential of urban design as a process of integration, as a responsible process to the social consequences of urban regeneration, and as proactive actions for the delivery of better urban design and as reactive actions for the iii management of the built environment. It also recommends actions in the process of urban design for local communities in Korean urban regeneration practices. Overall, this thesis highlights that there is a need to be a shift in the perspectives of urban design in urban regeneration towards urban design as a collaborative and an ongoing process of making better places, concerning not only improving existing urban environment and the quality of life for users, but also the management of the built environments the legacy of urban regeneration

Ultrafast resonant optical scattering from single gold nanorods: Large nonlinearities and plasmon saturation

We measure nonlinear optical scattering from individual Au nanorods excited by ultrafast laser pulses on resonance with their longitudinal plasmon mode. Isolating single rods removes inhomogeneous broadening and allows the measurement of a large nonlinearity, much greater than that of nanorod ensembles. Surprisingly, the ultrafast nonlinearity can be attributed entirely to heating of conduction electrons and does not exhibit any response associated with coherent plasmon oscillation. This indicates a previously unobserved damping of strongly driven plasmons.Comment: Revised tex

Common Mode Noise Reduction for an LLC Resonant Converter by Using Passive Noise Cancellation

This paper describes the application of a passive noise cancellation method to a prototype inductor-inductor-capacitor (LLC) resonant converter by placing a compensation winding in a transformer to reduce common mode noise. The connection method for the compensation winding is investigated. A circuit analysis is implemented for the displacement currents between the primary and secondary windings in the transformer. The analyzed displacement currents are verified by performing a circuit simulation and a proper compensation winding connection that reduces common mode noise is found. The measurement results show that common mode noise is reduced effectively up to 20 dB in the 1 to 7 MHz frequency region for the prototype LLC resonant converter by using the proposed passive noise cancellation method.clos

Uniaxial Bond Stress-Slip Relationship of Reinforcing Bars in Concrete

This paper documents a study carried out on the estimation of the bond stress-slip relationship for reinforced concrete members under axial tension loading. An analytical model is proposed that utilizes the conventional bond stress-slip theories as well as the characteristics of deformed bar and concrete cross-sectional area. An equation for the estimation of the bond stress is formulated as the function of nondimensional factors (e.g., bond stress, slip, etc.). The validity, accuracy, and efficiency of the proposed model are established by comparing the analytical results with the experimental data and the JSCE design codes, as well as the analytical models given by Ikki et al. and Shima. The analytical results presented in this paper indicate that the proposed model can effectively estimate the bond stress-slip relationship of reinforced concrete members under axial tension loading

Experimental Study of Flexural Behavior of Reinforced Concrete Beam Strengthened with Prestressed Textile-Reinforced Mortar

In this study, nine specimens were experimentally tested to analyze the strengthening efficiency of textile-reinforced mortar (TRM) and the difference in flexural behavior between prestressed and non-prestressed TRM-strengthened reinforced concrete beam. The test results show that TRM strengthening improves the flexural strength of TRM-strengthened reinforced concrete beams with alkali-resistant-(AR-) glass textile as well as that with carbon textile. However, in the case of textile prestressing, the strengthening efficiency for flexural strength of the AR-glass textile was higher than that of the carbon textile. The flexural stiffness of AR-glass textiles increased when prestressing was introduced and the use of carbon textiles can be advantageous to reduce the decreasing ratio of flexural stiffness as the load increased. In the failure mode, textile prestressing prevents the damage of textiles effectively owing to the crack and induces the debonding of the TRM

Behavior of Concrete Columns Repaired with Polymer Mortar and Epoxy Fiber Panel

Underwater structures are not easy to check for the degree of damage or to repair and strengthen damaged regions. Even during repair and strengthening, quality control is very difficult, because the work is done under water. Moreover, underwater structures severely deteriorate, owing to special environmental conditions. If this deterioration continues, the structures face serious structural problems, because of the corrosion of steel rods and the loss of concrete sections. Repairing or strengthening underwater structures requires effective, economic underwater repair and reinforcement techniques that allow the same working conditions as on the ground while maintaining dry condition for the repair sections. However, systematic studies on the repair and strengthening techniques for underwater structures are insufficient. This study proposes a new repair method for underwater structures, which applies epoxy fiber panel forms and shear connectors. To demonstrate the repair effects, this study compared and evaluated the failure modes and repair effects by the surface condition of repair sections, by applying various repair methods, in consideration of the ground and underwater conditions

Experimental Study on Flexural Behavior of TRM-Strengthened RC Beam: Various Types of Textile-Reinforced Mortar with Non-Impregnated Textile

In this study, to compare strengthening efficiency and flexural behaviors of textile- reinforced mortar (TRM) according to various types of strengthening methods without the textile being impregnated, ten specimens were tested. The results showed that TRM was beneficial for uniform distribution of cracks and increased the strengthening efficiency and load-bearing capacity, as textile reinforcement ratio and textile lamination increased and the mesh size of the textile decreased and mechanical end anchorage applied. However, the strengthening effect was shown obviously until the yield load considering structural safety and serviceability

Flexural Behavior of Textile Reinforced Mortar-Strengthened Reinforced Concrete Beams Subjected to Cyclic Loading

Textile-reinforced mortar (TRM) is used to strengthen reinforced concrete (RC) structures using a textile and inorganic matrix. TRM is a part of textile-based composites; the basic structural behaviors, application methods, and methodologies for the extension of actual structures in TRM were studied. However, structural behavior and performance verification which depict the long-term service situation and fatigue is limited. Therefore, this study, verified the flexural behavior of TRM-strengthened beams and their fatigue performances using carbon- and alkali-resistant (AR) glass textiles through 200,000 load cycles. TRM-strengthened beams were applied to an optimization strengthening method which consisted of whether the textile was straightened. According to the test results, the strengthening efficiency of TRM-strengthened beams when subjected to cyclic loading was lower than that of the monotonic loading, except for the straightened carbon textile specimen. The average efficiency of the AR-glass textile (straightened and non-straightened) and carbon (non-straightened) was 0.86 compared to the TRM-strengthened beam subjected to monotonic loading in terms of flexural strength. In the case of deflection, the average efficiency of the AR-glass textile type was similar to the monotonic loading test results, while that of the non-straightened carbon textile was improved. The Ca-S specimen that was used to straighten the carbon textile showed a reliable structural performance with a strength efficiency of 0.99 and a deflection efficiency of 0.97 compared to the monotonic load test. Therefore, TRM strengthening using a straightened carbon textile is expected to be sufficient for the fatigue design of TRM-strengthened beams