Relación entre historia de la filosofía y filosofía teorética

Resumen: El presente artículo, después de trazar un resumen del recorrido de los modos de historiar la filosofía, enfoca el tema de la relación entre ambos aspectos: el de la filosofía teorética y el de la historia de la filosofía. Toma distancia crítica tanto de la concepción que independiza la historia de la filosofía de la labor de búsqueda de la verdad teorética, como de la identificación de ambas dimensiones, tesis que tomó forma sobre todo a partir de Hegel. Propone una aplicación de la hermenéutica en la lectura del pasado filosófico, para abrir nuevas cuestiones y horizontes de búsqueda en el mundo de la realidad y en las exigencias y desafíos de la propia época histórica. Dicha hermenéutica, a su vez, no se desliza hacia el relativismo, sino que confirma la perennidad de lo verdadero en su persistencia fecunda a lo largo del tiempo.

Studies on two-phase co-current air/non-Newtonian shear-thinning fluid flows in inclined smooth pipes

In this work. co-current flow characteristics of air/non-Newtonian liquid systems in inclined smooth pipes are studied experimentally and theoretically using transparent tubes of 20, 40 and 60 turn in diameter. Each tube includes two 10 m lone pipe branches connected by a U-bend that is capable of being inclined to any angle, from a completely horizontal to a fully vertical position. The flow rate of each phase is varied over a wide range. The studied flow phenomena are bubbly, plug flow, slug flow, churn flow and annular flow. These are observed and recorded by a high flow. stratified flow. -speed camera over a wide range of operating conditions. The effects of the liquid phase properties, the inclination angle and the pipe diameter on two-phase flow characteristics are systematically studied. The Heywood-Charles model for horizontal flow was modified to accommodate stratified flow in inclined pipes, taking into account the average void fraction and pressure drop of the mixture flow of a gas/non-Newtonian liquid. The pressure drop gradient model of Taitel and Barnea for a gas/Newtonian liquid slug flow was extended to include liquids possessing shear-thinning flow behaviour in inclined pipes. The comparison of the predicted values with the experimental data shows that the models presented here provide a reasonable estimate of the average void fraction and the corresponding pressure drop for the mixture flow of a gas/ non-Newtonian liquid. (C) 2007 Elsevier Ltd. All rights reserved.

Wire array photovoltaics

Over the past five years, the cost of solar panels has dropped drastically and, in concert, the number of installed modules has risen exponentially. However, solar electricity is still more than twice as expensive as electricity from a natural gas plant. Fortunately, wire array solar cells have emerged as a promising technology for further lowering the cost of solar.

Si wire array solar cells are formed with a unique, low cost growth method and use 100 times less material than conventional Si cells. The wires can be embedded in a transparent, flexible polymer to create a free-standing array that can be rolled up for easy installation in a variety of form factors. Furthermore, by incorporating multijunctions into the wire morphology, higher efficiencies can be achieved while taking advantage of the unique defect relaxation pathways afforded by the 3D wire geometry.

The work in this thesis shepherded Si wires from undoped arrays to flexible, functional large area devices and laid the groundwork for multijunction wire array cells. Fabrication techniques were developed to turn intrinsic Si wires into full p-n junctions and the wires were passivated with a-Si:H and a-SiNx:H. Single wire devices yielded open circuit voltages of 600 mV and efficiencies of 9%. The arrays were then embedded in a polymer and contacted with a transparent, flexible, Ni nanoparticle and Ag nanowire top contact. The contact connected >99% of the wires in parallel and yielded flexible, substrate free solar cells featuring hundreds of thousands of wires.

Building on the success of the Si wire arrays, GaP was epitaxially grown on the material to create heterostructures for photoelectrochemistry. These cells were limited by low absorption in the GaP due to its indirect bandgap, and poor current collection due to a diffusion length of only 80 nm. However, GaAsP on SiGe offers a superior combination of materials, and wire architectures based on these semiconductors were investigated for multijunction arrays. These devices offer potential efficiencies of 34%, as demonstrated through an analytical model and optoelectronic simulations. SiGe and Ge wires were fabricated via chemical-vapor deposition and reactive ion etching. GaAs was then grown on these substrates at the National Renewable Energy Lab and yielded ns lifetime components, as required for achieving high efficiency devices.

Problemen Ebazpena Lehen Hezkuntzan

Lan honen helburua, EAE-ko curriculuma oinarritzat hartuz, Lehen Hezkuntzako testuliburuetan sormena eta intuizioa garatzen diren problemak lantzen diren, aztertu eta analizatzea da. Horrez gain, testuliburuan atal honetan gabeziak dituzten haur talde batean, mota hauetako problemak praktikan jarriko dira, beraien jarrera eta erantzuna aztertuz.

The Private Provision of International Impure Public Goods: the Case of Climate Policy

33 p.

Taking a systems-oriented view of phosphorous enrichment in fresh waters

Eutrophication of fresh waters through anthropogenic enrichment by phosphorus is a global problem. The role of phosphorus enrichment in the formation of blooms of toxic blue-green algae (Cyanobacteria) in fresh waters is well established and of considerable concern in terms of human and animal health, loss of water resources and amenities, threats to fish stocks, and aesthetic considerations. Cultural eutrophication also poses threats to the ecosystem balance in fresh waters, with implications for wildlife. This article examines phosphorus enrichment in fresh waters from a systems perspective, and explores systems solutions that may be helpful in the development of more sustainable policies.

Estrategias empresariales en el sector bancario

[ES]La internacionalización ha sido una de las principales estrategias de crecimiento llevadas a cabo por la gran banca española, sobre todo a partir de la década de los 90. Es en esta década cuando hubo un destacable salto por parte de las entidades españolas hacia el mercado latinoamericano en especial, así como hacia Europa y Estados Unidos. Por otro lado, una vez comenzada la crisis financiera -entre finales de 2007 y principios de 2008-, dicho proceso de expansión se vio mermado, debido a que la banca tuvo que afrontar una nueva etapa de reforzamiento interno en la que todavía sigue inmersa. En el presente trabajo, tomando como ejemplos los bancos Santander y BBVA, se tratarán de analizar tanto los motivos y destinos de la mencionada expansión internacional; así como el nuevo entorno en el que tras la crisis y, una vez realizados los distintos procesos regulatorios, el sistema bancario español tendrá que desarrollar su actividad. A su vez, también serán objeto de análisis los modelos de negocio planteados por las dos entidades, a través de los cuales podremos definir algunas de las estrategias que se presentan en este nuevo entorno económico-financiero.