The Economics of Gasification: A Market-Based Approach

This paper deals with the economics of gasification facilities in general and IGCC power plants in particular. Regarding the prospects of these systems, passing the technological test is one thing, passing the economic test can be quite another. In this respect, traditional valuations assume constant input and/or output prices. Since this is hardly realistic, we allow for uncertainty in prices. We naturally look at the markets where many of the products involved are regularly traded. Futures markets on commodities are particularly useful for valuing uncertain future cash flows. Thus, revenues and variable costs can be assessed by means of sound financial concepts and actual market data. On the other hand, these complex systems provide a number of flexibility options (e.g., to choose among several inputs, outputs, modes of operation, etc.). Typically, flexibility contributes significantly to the overall value of real assets. Indeed, maximization of the asset value requires the optimal exercise of any flexibility option available. Yet the economic value of flexibility is elusive, the more so under (price) uncertainty. And the right choice of input fuels and/or output products is a main concern for the facility managers. As a particular application, we deal with the valuation of input flexibility. We follow the Real Options approach. In addition to economic variables, we also address technical and environmental issues such as energy efficiency, utility performance characteristics and emissions (note that carbon constraints are looming). Lastly, a brief introduction to some stochastic processes suitable for valuation purposes is provided.

Blue upconversion Luminescence in Tm3+/Yb3+-Codoped New Oxyfluoride Tellurite Glass

The thermal stability, Raman spectrum and upconversion properties of Tm^(3+)/Yb^(3+) co-doped new oxyfluoride tellurite glass are investigated. The results show that Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass possesses good thermal stability, lower phonon energy, and intense upconversion blue luminescence. Under 980-nm laser diode (LD) excitation, the intense blue (475 nm) emission and weak red (649 nm) emission corresponding to the 1G4 -> 3H6 and 1G4 -> 3F4 transitions of Tm^(3+) ions respectively, were simultaneously observed at room temperature. The possible upconversion mechanisms are evaluated. The intense blue upconversion luminescence of Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass can be used as potential host material for the development of blue upconversion optical devices.

Synthesis of polycrystalline nanotubular Bi2Te3

Polycrystalline nanotubular Bi2Te3 could be prepared via a high-temperature solution process using nanoscale tellurium, decomposed from trioctylphosphine oxide (TOPO) extracted tellurium species (Te-TOPO), as sacrificial template. The formation of such tubular structure is believed to be the result of outward diffusion of Te during the alloying process. The electrical properties (Seebeck coefficient and electrical conductivity) of the polycrystalline nanotubular Bi2Te3 have been studied and the experimental results show that the electrical conductivity is approximately three orders of magnitude smaller than bulk bismuth telluride materials mainly due to the much larger resistance brought by the insufficient contact between the nanotubular structures.

L'Écho de Paris

1917/03/15 (Numéro 11899).

La razón filosófica y la razón católica

UANL

Una cadena humana cap al futur. 'Una cadena humana hacia el futuro'.

Resumen de la revista en catalán

Análisis del abordaje realizado por Colombia al crimen transnacional de la trata de personas como amenaza a la seguridad en el periodo 2004-2014: una mirada desde la securitización

El objetivo de esta monografía es analizar el abordaje a la trata de personas en Colombia durante el período 2004-2014 desde la teoría de la securitización, para determinar su posición en la agenda de seguridad del país. La hipótesis que se propone es que a través de algunos postulados de esta teoría es posible establecer que la trata de personas es un crimen transnacional que no ha sido percibido como amenaza para la seguridad del país, lo cual ha incidido en que no se hayan tomado medidas eficaces para contenerlo. A través de una investigación descriptiva que analiza las políticas de seguridad, y un ejercicio comparativo del abordaje gubernamental dado al secuestro durante este periodo, se intentará establecer una relación explicativa entre los postulados teóricos escogidos y el fenómeno analizado. Se espera también profundizar en el concepto de securitización y sus implicaciones para los estados y la población.