666 research outputs found
Optimal Carbon Taxes for Emissions Targets in the Electricity Sector
The most dangerous effects of anthropogenic climate change can be mitigated
by using emissions taxes or other regulatory interventions to reduce greenhouse
gas (GHG) emissions. This paper takes a regulatory viewpoint and describes the
Weighted Sum Bisection method to determine the lowest emission tax rate that
can reduce the anticipated emissions of the power sector below a prescribed,
regulatorily-defined target. This bi-level method accounts for a variety of
operating conditions via stochastic programming and remains computationally
tractable for realistically large planning test systems, even when binary
commitment decisions and multi-period constraints on conventional generators
are considered.
Case studies on a modified ISO New England test system demonstrate that this
method reliably finds the minimum tax rate that meets emissions targets. In
addition, it investigates the relationship between system investments and the
tax-setting process. Introducing GHG emissions taxes increases the value
proposition for investment in new cleaner generation, transmission, and energy
efficiency; conversely, investing in these technologies reduces the tax rate
required to reach a given emissions target
A Remarkable Tiphiiform Wasp in Mid-Cretaceous Amber from Myanmar (Hymenoptera: Tiphiidae)
The first tiphiid wasp (Aculeata: Euaculeata: Vespoidea: Tiphiiformes) in Cretaceous amber is described and figured. Thanatotiphia nyx, new genus and species, is represented by a male entombed in mid-Cretaceous (latest Albian) amber from Myanmar. Thanatotiphia possesses remarkable apomorphies in wing venation, lacks key traits of modern subfamilies, and is thus classified in a new subfamily, Thanatotiphiinae. The fossil is further shown to be nested well within the family, indicating that major lineages of Tiphiidae diverged by the mid-Cretaceous. The new taxon is compared with modern tiphiid subfamilies and the sparse fossil history of the family briefly overviewed
A Primitive Aphidiine Wasp in Albian Amber from Spain and a Northern Hemisphere Origin for the Subfamily (Hymenoptera: Braconidae: Aphidiinae)
A description of a new genus and species of braconid, Archephedrus stolamissus, from Early Cretaceous (Albian) amber from Moraza-Peñacerrada I (Spain) is here provided. This is the first fossil Aphidiinae described in Cretaceous amber. The fossil has some typical characters of the subfamily but possesses a unique assemblage of characters among aphidiines, such as a fairly robust abdomen, with a more pronounced articulation between the first and second, instead of the second and third, metasomal segments, as well as several wing venational traits. The distribution of this and other aphidiine fossils, as well as their putative phylogenetic placement as basal among Aphidiinae, is discussed, supporting a Northern rather than Southern Hemisphere origin for the lineage
Determinación del Desbalance en Sistemas Rotor-cojinete a velocidad constante: Método de Identificación Algebraica
The development of a mathematical model for an on-line algebraic identifier is presented in this work. This model is used for determining the unbalance and its related angular position on vibrating rotor-dynamic systems of multiple degrees of freedom. The proposed identifier was obtained from the basis of a finite element mathematical model for rotating systems of multiple degrees of freedom. The model was developed under the consideration of four degrees of freedom beam-type element, where rotational inertia, gyroscopic moments, shearing strains and inner and outer damping effects were included. The on time behavior of proposed identifier was assessed for unbalance identification and its related angular position; the constant-speed unbalanced vibration response obtained from numerical simulation was used as input data
Acción de las radiaciones U.V. sobre el poli (cloruro de vinilo) flexible
The aim of this work is the study of the U.V. radiations effects on plasticized Poly (vinyl chloride) used as waterproofing membrane in Building and also in Public Works.
The ageing fact due to U.V. radiations has been followed for 3.000 hours, checking the changes produced in the composition of the material, on its mechanical characteristics and microscopic structure.En este trabajo se trata de poner de manifiesto el efecto de las radiaciones U.V. sobre el poli (cloruro de vinilo) plastificado, utilizado en forma de lámina para la impermeabilización, tanto en la Edificación como en la Obra Pública. La acción del envejecimiento por radiaciones U.V. se ha seguido a lo largo de 3.000 horas, comprobando las alteraciones producidas en la composición del material, características mecánicas y estructura microscópica
Modificación de Betún-Venezuela por reacción de Friedel y Crafts
In this work, a Venezuelan-bitumen of newtonian nature was modified by Friedel and Crafts reaction, changing it in new materials that present pseudoplastic characteristics, with very different properties from the original product. These new materials are harder and have less thermical susceptibility and allow us to use them in many applications such as paving and roofing. The modifications have been made with rubbers, PVC, phtalic anhydride, maleic anhydride, 1, 2-propyleneglycol, hexamethylenediisocyanate and toluylene-2,4-diisocyanate.En el presente trabajo se modificó un betún-Venezuela, de naturaleza newtoniana, mediante reacción de Friedel y Crafts, transformándolo en unos nuevos materiales, ya de carácter pseudoplástico, con unas propiedades notablemente distintas a las del producto de partida. Los nuevos materiales son más duros y de menor susceptibilidad térmica, lo que los hace útiles para pavimentación e impermeabilización. Las modificaciones se han realizado con cauchos, policloruro de vinilo, anhídrido ftálico, anhídrido maléico, 1,2-propanodiol, hexametilendiisocianato y toluen-2,4-diisocianato
Tuning the carrier injection barrier of hybrid metal–organic interfaces on rare earth-gold surface compounds
Magnetic hybrid metal-organic interfaces possess a great potential in areas such as organic spintronics and quantum information processing. However, tuning their carrier injection barriers on-demand is fundamental for the implementation in technological devices. We have prepared hybrid metal-organic interfaces by the adsorption of copper phthalocyanine CuPc on REAu2 surfaces (RE = Gd, Ho and Yb) and studied their growth, electrostatics and electronic structure. CuPc exhibits a long-range commensurability and a vacuum level pinning of the molecular energy levels. We observe a significant effect of the RE valence of the substrate on the carrier injection barrier of the hybrid metal-organic interface. CuPc adsorbed on trivalent RE-based surfaces (HoAu2 and GdAu2) exhibits molecular level energies that may allow injection carriers significantly closer to an ambipolar injection behavior than in the divalent case (YbAu2)
Habilidades del psicólogo en drogodependencias
Las habilidades del terapeuta constituyen un aspecto fundamental para la consecución de los distintos objetivos que al psicólogo se le plantean en el transcurso de su intervención con el usuario drogodependiente. En este articulo se presenta una revisión de las habilidades que los autores consideran imprescindibles, aportando ejemplos prácticos y con independencia de la orientación teórica del psicólogo. Las habilidades técnicas o profesionales se refieren a conocimientos teóricos y prácticos; el afltocontrol emocional, incluyendo tanto el afrontamiento ef caz por parte del psicólogo de ciertas situaciones ante el usuario, y especificamente si éste es un drogodelincuente, como el afrontamiento del burn out; y por último, las habilidades sociales, en las que se sustenta la interacción entre el psicólogo y el usuario, destacando la asertividad y la empatia. Finalmente se revisan distintos aspectos y principios generales referidos a la ética profesional en la práctica de la Psicologia Clínica
Cross-Comparison of Climate Change adaptation Strategies Across Large River Basins in Europe, Africa and Asia
A cross-comparison of climate change adaptation strategies across regions was performed, considering six large river basins as case study areas. Three of the basins, namely the Elbe, Guadiana, and Rhine, are located in Europe, the Nile Equatorial Lakes region and the Orange basin are in Africa, and the Amudarya basin is in Central Asia. The evaluation was based mainly on the opinions of policy makers and water management experts in the river basins. The adaptation strategies were evaluated considering the following issues: expected climate change, expected climate change impacts, drivers for development of adaptation strategy, barriers for adaptation, state of the implementation of a range of water management measures, and status of adaptation strategy implementation. The analysis of responses and cross-comparison were performed with rating the responses where possible. According to the expert opinions, there is an understanding in all six regions that climate change is happening. Different climate change impacts are expected in the basins, whereas decreasing annual water availability, and increasing frequency and intensity of droughts (and to a lesser extent floods) are expected in all of them. According to the responses, the two most important drivers for development of adaptation strategy are: climate-related disasters, and national and international policies. The following most important barriers for adaptation to climate change were identified by responders: spatial and temporal uncertainties in climate projections, lack of adequate financial resources, and lack of horizontal cooperation. The evaluated water resources management measures are on a relatively high level in the Elbe and Rhine basins, followed by the Orange and Guadiana. It is lower in the Amudarya basin, and the lowest in the NEL region, where many measures are only at the planning stage. Regarding the level of adaptation strategy implementation, it can be concluded that the adaptation to climate change has started in all basins, but progresses rather slowl
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