A generalized self-consistent method accounting for fiber section shape

A three-phase confocal elliptical cylinder model is proposed for fiber-reinforced composites, in terms of which a generalized self-consistent method is developed for fiber-reinforced composites accounting for variations in fiber section shapes and randomness in fiber section orientation. The reasonableness of the fiber distribution function in the present model is shown. The dilute, self-consistent, differential and Mori-Tanaka methods are also extended to consider randomness in fiber section orientation in a statistical sense. A full comparison is made between various micromechanics methods and with the Hashin and Shtrikman's bounds. The present method provides convergent and reasonable results for a full range of variations in fiber section shapes (from circular fibers to ribbons), for a complete spectrum of the fiber volume fraction (from 0 to 1, and the latter limit shows the correct asymptotic behavior in the fully packed case) and for extreme types of the inclusion phases (from voids to rigid inclusions). A very different dependence of the five effective moduli on fiber section shapes is theoretically predicted, and it provides a reasonable explanation on the poor correlation between previous theory and experiment in the case of longitudinal shear modulus.

Brazil’s patent reform : innovation towards national competitiveness

Adaptação para a língua inglesa da obra “A revisão da lei de patentes: inovação em prol da competitividade nacional

Does Immigration Raise Natives’ Income? National and Regional Evidence from Spain

How immigration affects the labor market of the host country is a topic of major concern for many immigrant-receiving nations. Spain is no exception following the rapid increase in immigrant flows experienced over the past decade. We assess the impact of immigration on Spanish natives’ income by estimating the net immigration surplus accruing at the national level and at high immigrant-receiving regions while taking into account the imperfect substitutability of immigrant and native labor. Specifically, using information on the occupational densities of immigrants and natives of different skill levels, we develop a mapping of immigrant-to-native self-reported skills that reveals the combination of natives across skills that would be equivalent to an immigrant of a given self-reported skill level, which we use to account for any differences between immigrant self-reported skill levels and their effective skills according to the Spanish labor market. We find that the immigrant surplus amounts to 0.04 percent of GDP at the national level and it is even higher for some of the main immigrant-receiving regions, such as Cataluña, Valencia, Madrid, and Murcia.

Sociedades Cooperativas. Aspectos Contables Singulares

[ES] Las sociedades cooperativas han visto recientemente reforzada su normativa contable con la aprobación de la ORDEN ECO/3614/2003 que tiene por objeto la adaptación de las Normas de valoración y elaboración de cuentas anuales aprobada en el Plan General de Contabilidad a las características de estas entidades.

Conceptual model of salt marsh management on Merritt Island National Wildlife Refuge, Florida: final report

Diking and holding water on salt marshes ("impounding" the marsh) is a management technique used on Merritt Island National Wildlife Refuge (MINWR) and elsewhere in the Southeast to: a) prevent the reproduction of saltmarsh mosquitos, and b) attract wintertering waterfowl and other marsh, shore, and wading birds. Because of concern that diking and holding water may interfere with the production of estuarine fish and shellfish, impoundment managers are being asked to consider altering management protocol to reduce or eliminate any such negative influence. How to change protocol and preserve effective mosquito control and wildlife management is a decision of great complexity because: a) the relationships between estuarine organisms and the fringing salt marshes at the land-water interface are complex, and b) impounded marshes are currently good habitat for a variety of species of fish and wildlife. Most data collection by scientists and managers in the area has not been focused on this particular problem. Furthermore, collection of needed data may not be possible before changes in protocol are demanded. Therefore, the purpose of this document is two-fold: 1) to suggest management alternatives, given existing information, and 2) to help identify research needs that have a high probability of leading to improved simultaneous management of mosquitos, waterfowl, other wildlife, freshwater fish, and estuarine fish and shellfish on the marshland of the Merritt Island National Wildlife Refuge. (92 page document)

Manual Control of Phragmites australis on Pondshores of Cape Cod National Seashore, Masachusetts, USA

The non-native, invasive genotype of the common reed ( Phragmites australis (Cav.) Trin. ex Steudel) has become a problem of significant proportions throughout wetlands of North America (Saltonstall 2001). Although attempts to suppress or eradicate Phragmites have utilized a wide variety of techniques, herbicides have generally been most effective (Marks et al. 1994). In the spring, mid-summer, and late summer of 2003, we attempted to opportunistically control Phragmites in five freshwater ponds within Cape Cod National Seashore (CCNS) by repeatedly severing stems underwater, at ground level.(PDF has 4 pages.)

System requirement report for ‘Level 2’: national management institutions, Fisheries Department in Cambodia

(51 p.)