MEGAREGIONS: CAUSES, SCOPE, CHARACTERISTICS AND CHALLENGES OF DEVELOPMENT

Megalopolis is considered as a merger of a number of agglomerations, which have synergistic effect. The megaregion is a more complex system relative to its constituent agglomerations and has the sum of their synergies and new emergent qualities. The domestic and foreign terminology used for the designation of megaregions is given. The existential cause is determined, the economic, social factors and synergistic effects of the functioning of mega-agglomerations are identified. The stages of the structural and planning formation of megalopolises are reflected graphically and in tabular form. The correlation between the capacity building of megalopolises and the development of the transport infrastructure of their territories is noted. The structural and planning characteristics and urban development trends of megalopolises are revealed. The characteristics of the types of planning structure of megalopolises are given. Polycentricity and prevalence of linear-axial development of the architectural and planning structure of megalopolises are shown. The constant territorial and spatial expansion of mega agglomerations is noted. The modern urban planning problems of megalopolises' development are set: the lack of urban regulation of their development, the lack of professional personnel in the field of their planning, the lack of a theory of megalopolises' development, excessive pressure on ecosystems. Extrapolation of the territorial growth of the combined metro areas allows to predict their merger into a single urbanized "network" of the planet. The prerequisites for the development of the latest urban development trend of the XXI century – the formation of crossborder megaregions are highlighted.

Influence of Property Variation on Natural Convection in an Isothermal Vertical Finned Channel: An Extended Study

Boussineśq and non-Boussineśq fluid with thermo-physical property variation have been investigated for a vertical fin array. Computations are executed for the range of parameter such as Grashof number 1.86 × 105 and 4.42 × 105, non-dimensional S* = 0.2, 0.3, and 0.5, and non-dimensional clearance C* = 0.10, 0.15, and 0.40. The axial development of various fluid flow quantities, such as the pressure defect (P*), local Nusselt number (Nul), and the bulk temperature of the fluid (θb) has been presented for each of the property combinations. Nul is observed to have reduced by 70% near the exit from the Boussineśq fluid with fixed viscosity and thermal conductivity to the non-Boussineśq fluid with the variable property. Furthermore, the overall Nusselt number (Nu) at S* = 0.2 in an isothermal vertical fin array for an increase in Gr from 1.86 × 105 to 4.42 × 105 with different combination of properties such as Boussineśq fluid with fixed viscosity and thermal conductivity (ρb μc kc), Boussineśq fluid with variable viscosity and thermal conductivity (ρb μv kv), non-Boussineśq fluid with fixed viscosity and thermal conductivity (ρv μc kc), and non-Boussineśq fluid with variable viscosity and thermal conductivity (ρv μv kv) are observed to have an increase of 138%, 148%, 150%, and 160%, respectively.