203,646 research outputs found

    Informality and the Development and Demolition of Urban Villages in the Chinese Peri-urban Area

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    The fate of Chinese urban villages (chengzhongcun) has recently attracted both research and policy attention. Two important unaddressed questions are: what are the sources of informality in otherwise orderly Chinese cities; and, will village redevelopment policy eliminate informality in the Chinese city? Reflecting on the long-established study of informal settlements and recent research on informality, it is argued that the informality in China has been created by the dual urban-rural land market and land management system and by an underprovision of migrant housing. The redevelopment of chengzhongcun is an attempt to eliminate this informality and to create more governable spaces through formal land development; but since it fails to tackle the root demand for unregulated living and working space, village redevelopment only leads to the replication of informality in more remote rural villages, in other urban neighbourhoods and, to some extent, in the redeveloped neighbourhoods. © 2012 Urban Studies Journal Limited

    Orbital-resolved vortex core states in FeSe Superconductors: calculation based on a three-orbital model

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    We study electronic structure of vortex core states of FeSe superconductors based on a t2g_{2g} three-orbital model by solving the Bogoliubov-de Gennes(BdG) equation self-consistently. The orbital-resolved vortex core states of different pairing symmetries manifest themselves as distinguishable structures due to different quasi-particle wavefunctions. The obtained vortices are classified in terms of the invariant subgroups of the symmetry group of the mean-field Hamiltonian in the presence of magnetic field. Isotropic ss and anisotropic ss wave vortices have G5G_5 symmetry for each orbital, whereas dx2y2d_{x^2-y^2} wave vortices show G6G^{*}_{6} symmetry for dxz/yzd_{xz/yz} orbitals and G5G^{*}_{5} symmetry for dxyd_{xy} orbital. In the case of dx2y2d_{x^2-y^2} wave vortices, hybridized-pairing between dxzd_{xz} and dyzd_{yz} orbitals gives rise to a relative phase difference in terms of gauge transformed pairing order parameters between dxz/yzd_{xz/yz} and dxyd_{xy} orbitals, which is essentially caused by a transformation of co-representation of G5G^{*}_{5} and G6G^{*}_{6} subgroup. The calculated local density of states(LDOS) of dx2y2d_{x^2-y^2} wave vortices show qualitatively similar pattern with experiment results. The phase difference of π4\frac{\pi}{4} between dxz/yzd_{xz/yz} and dxyd_{xy} orbital-resolved dx2y2d_{x^2-y^2} wave vortices can be verified by further experiment observation

    Sustainability in design: now! Challenges and opportunities for design research, education and practice in the XXI century

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    Copyright @ 2010 Greenleaf PublicationsLeNS project funded by the Asia Link Programme, EuropeAid, European Commission

    Comparative study of Steel-FRP, FRP and steel reinforced coral concrete beams in their flexural performance

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    In this paper, a comparative study of Carbon Fiber Reinforced Polymer (CFRP) Bar and Steel-Carbon Fiber Composite Bar (SCFCB) reinforced coral concrete beams are made through a series experimental tests and theoretical analysis. The flexural capacity, crack development and failure modes of CFRP and SCFCB reinforced coral concrete were investigated in detail. They are also compared to ordinary steel reinforced coral concrete beams. The results show that under the same condition of reinforcement ratio, the SCFCB reinforced beam exhibits better performance than those of the CFRP reinforced beams, and its stiffness is slightly lower than that of the steel reinforced beam. Under the same load condition, the crack width of the SCFCB beam is between the steel reinforced beam and the CFRP bar reinforced beam. Before the steel core yields, the crack growth rate of SCFCB beam is similar to the steel reinforced beam. SCFCB has a higher strength utilization rate, about 70% -85% of its ultimate strength. The current design guidance was also examined based on the test results. It was found that the existing design specifications for FRP reinforced normal concrete is not suitable for SCFCB reinforced coral concrete structures