839 resultados para Characteristics physical and industry
Resumo:
Trade affects the internal location of industry in two ways: it induces firms to specialize and it expands the set of markets that firms serve. If there are industry-specific external economies, firms in related industries will spatially agglomerate (Hanson 1996a). In the context of economic integration, diminished barriers to trade affect industry location particularly in less developed countries. As described below, regional agreements in North America and Europe have caused frontier regions to expand. These regions, which include border regions and port cities, have advantages over internal regions in terms of access to foreign markets. Since trade liberalization induces many firms in developing countries to participate in production networks and to specialize in labor-intensive activities such as assembling and processing of foreign-made components, their inputs as well as final products need to be carried across borders. Therefore, the best industry location, one that minimizes transport costs, is likely to shift to frontier regions. In East Asia, China has developed rapidly since it opened up to international trade. Simultaneously, a large amount of foreign direct investment (FDI) has been attracted and industry agglomerations have been formed in coastal regions, that is, frontier regions linked to the global market by sea, leaving many internal regions behind. Similarly, Cambodia, Laos, Myanmar, and Vietnam (CLMV) have joined AFTA and/or the WTO and liberalized international trade since the 1990s. Moreover, transport infrastructures such as the East-West Economic Corridor, the Southern Economic Corridor, and the North-South Economic Corridor have been built and narrowed economic distances in the Greater Mekong Subregion (GMS). As a result, frontier regions are likely to increase their location advantages and lure labor-intensive operations from neighboring countries. It is expected that, as has happened in North America and Europe, economic integration in East Asia will significantly affect internal geography in CLMV. In this study, I first review theories relevant to economic integration and industry location within a country. In particular, emphasis is placed on the new economic geography (NEG). Secondly, empirical results for North America and Europe are surveyed since they have preceded East Asia in regional integration and a substantial number of studies have been conducted on these regions. The final section summarizes and discusses implications for internal geography in CLMV.
Resumo:
Following the success achieved in previous research projects usin non-destructive methods to estimate the physical and mechanical aging of particle and fibre boards, this paper studies the relationships between aging, physical and mechanical changes, using non-destructive measurements of oriented strand board (OSB). 184 pieces of OSB board from a French source were tested to analyze its actual physical and mechanical properties. The same properties were estimated using acoustic non-destructive methods (ultrasound and stress wave velocity) during a physical laboratory aging test. Measurements were recorded of propagation wave velocity with the sensors aligned, edge to edge, and forming an angle of 45 degrees, with both sensors on the same face of the board. This is because aligned measures are not possible on site. The velocity results are always higher in 45 degree measurements. Given the results of statistical analysis, it can be concluded that there is a strong relationship between acoustic measurements and the decline in physical and mechanical properties of the panels due to aging. The authors propose several models to estimate the physical and mechanical properties of board, as well as their degree of aging. The best results are obtained using ultrasound, although the difference in comparison with the stress wave method is not very significant. A reliable prediction of the degree of deterioration (aging) of board is presented.
Resumo:
The ability to reproduce reduced gravity conditions for long periods is one of the reasons why the orbiting laboratory is so attractive. In this paper several fluid dynamics problem areas are reviewed in which zero-gravity conditions are of great importance. Although emphasis is placed on space processing, there are some older problems also in which gravity masks the phenomcna, impeding a reasonably simple approach to the solution. Three problems are considered: Thermal convection under reduced gravity. The dumping effect ofsurface gravity waves at the outset of convection induced by surface tractions is discussed in particular. The existence of convection is of concern for some satellite thermal control techniques presently used, and for most of the proposed manufacturing processes. Whereas convection should be normally avoided, problems related to the containerless stirring ofa melt constitute an exception. Secondly, gravity and chemical reactions. Although chemical reactions are independent of gravity because of the small mass of the molecules and atoms involved, in many cases the reaction rate dcpends on the arrival of the species to the reaction zone. When the arrival process is buoyancy-controlled, the net specd of the reaction will be affected by the gravity. Thirdly, two-phase flows under reduced gravity provkle interesting problems from boiling heat transfer to degasslng of melts. This part of the paper deals only with the measurement of sound veiocity in a liquid containing bubbles. It is suggested that such measurements should be mude under reduced gravity to provide reliable residís.
Resumo:
The separation of the lower stage of the ARIANE 5 Vehicle Equipment Bay (VEB) Structure is to be done using a pyrotechnic device. The wave propagation effects produced by the explosion can affect the electronic equipment, so it was decided to analyze, using both physical and numerical modeling, a small piece of the structure to determine the distribution of the accelerations and the relative importance of damping, stiffness, connections, etc. on the response of the equipment.
Resumo:
The basics of laser driven neutron sources, properties and possible applications are discussed. We describe the laser driven nuclear processes which trigger neutron generation, namely, nuclear reactions induced by laser driven ion beam (ion n), thermonuclear fusion by implosion and photo-induced nuclear (gamma n) reactions. Based on their main properties, i.e. point source (<100 μm) and short durations (< ns), different applications are described, such as radiography, time-resolved spectroscopy and pump-probe experiments. Prospects on the development of laser technology suggest that, as higher intensities and higher repetition rate lasers become available (for example, using DPSSL technology), laser driven methodologies may provide neutron fluxes comparable to that achieved by accelerator driven neutron sources in the near future.