596 research outputs found
Energy integration of high pressure processes using gas turbines and internal combustion engines
High pressure processes (e.g. sustainable hydrothermal manufacturing of nanomaterials [1], supercritical water oxidation (SCWO) [2] and biomass hydrolysis [3]) require high operational conditions. Water at high pressure and temperature conditions improves kinetic, selectivity and efficiency of these processes but entail high-energy operational expenditure. Use of fluids at high operational conditions makes necessary to supply heat of high quality, as well as power. Because of this, it is necessary to study reasonable solutions for energy recovery and integration in order to achieve the energy self-sufficiency of the process and, if possible, the net power production and with a viable efficiency [4].
In this work, the energy integration of supercritical water oxidation process is being studied. One solution that has been recently proposed is the integration of supercritical processes with energy production in cogeneration or Combined Heat and Power (CHP) cycles. Cogeneration is defined as the simultaneous production of various forms of energy – being the most frequent heat and shaft work, i.e., power – from one power source. The implementation of CHP processes is often joined to the use of gas turbines (GT) [3, 5]. SCWO process produces a high pressure reactor outlet stream, being these mainly composed of water, nitrogen and carbon dioxide and can be thermally integrated if there is a necessity of heat in other parts of the process. At the same time, it is possible to use this effluent to implement a steam injection in the gas turbine, which will improve the efficiency of the global process. This mechanism links the process of SCWO with the cogeneration process (Fig. 1). Steam injection is a technique which can increase the ability of a plant to generate extra power without burning extra fuel and requiring moderate capital investment. In its most basic form, steam injection works by increasing the global mass flow rate through the gas turbine without increasing the mass of air compressed.
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Thermal transport in glassy selenium: The role of low-frequency librations
7 págs.; 3 figs.The experimental curves giving the temperature dependence of the thermal conductivity of glassy selenium are considered in detail. The observed behavior can be taken into account quantitatively if the densities of states for short-wavelength phonons as well as for low-energy librations arising from computer simulations are used for the calculations. In particular, it is shown that the lowest frequency excitations of a chain of selenium atoms can give due account of the plateau observed at temperatures about 2-10 K. The implications of the present findings for the current debate regarding the mechanisms for thermal transport in glasses are finally discussed. © 1994 The American Physical Society.This work has been supported by DGICYT Grant No. PB92-0114-C03Peer Reviewe
Planification of conservation and preservation program in Maneto Group dog
In the present paper we are describing the planification of a conservation and preservation programme of the Maneto dog breed group in developing under two consecutive phases. Firstly we show the results obtained in the ethnogenetic characterization (mopho-structural and external), but also a preliminary report of the functional, genetic and environmental information collection, using a zootechnic inquiry as applications of the first phase. In the second phase we are proposing some actuation destines to the reproducers evaluation and the planification of the breeding system to develop a complete conservation programme for this breed.En el presente trabajo se describen la planificación de un programa de conservación y preservación en la Agrupación Racial del Perro Maneto a desarrollar en dos fases sucesivas. Primeramente se muestran los resultados obtenidos en la caracterización etnogenética (morfoestructural y faneróptica) así como un esbozo de la recogida de información funcional, genética y del entorno a través de una encuesta zootécnica como acciones englobadas en la primera fase. En la segunda fase se proponen actuaciones encaminadas a la valoración de reproductores y la planificación de los sistemas de cría conducentes al establecimiento de un programa de conservación integral en la raza
Morphostructural characterisation of Spanish Alano as a base for its conservation: preliminar results
Using 68 pure exemplars of the Spanish Alano Dog Breed (37 males and 31 females) we have developed a preliminary study of the breed characterisation analysing several morphostructural variables as a base for the definition of racial pattern, considering that a one of the main objectives of the project entitled Planning of the recuperation and conservation of the Spanish Alano canine breed. All the studied zoometric variables reflected bigger values if males than in females, but we could not proved statistically a clear sexual dimorphism in most of the studied variables. Our results coincide with descriptions and data published by other authors with respect to this breed. In general, from this study we conclude that this population is characterised by braquicephalic proportions, and sublongilineous body proportions, all inside a strong and compact morphostructure. It permit us to clasify this breed inside the group of light molosoids caught dogs.Sobre un total de 68 ejemplares de la raza Alano Español (37 machos y 31 hembras) se realiza un estudio de caracterización racial preliminar, analizando diversas variables morfoestructurales, como base para su utilización en la redacción del patrón racial, considerado como uno de los objetivos iniciales prioritarios en el proyecto denominado Planificación de la recuperación y conservación de la raza canina Alano Español. Todas las variables zoométricas estudiadas reflejaron valores mayores en machos que en hembras, aunque no comprobamos estadísticamente un dimorfismo sexual manifiesto en la mayoría de dichas variables. Asimismo nuestros resultados concuerdan con las descripciones y datos aportados por los distintos autores que estudiaron esta raza anteriormente. En líneas generales, de este estudio se puede concluir que la población estudiada se caracteriza por presentar características braquicéfalas, y proporciones corporales sublongilíneas dentro de una morfoestructura general fuerte y compacta, lo que nos permite encuadrar esta raza dentro del grupo de perros molosos ligeros de presa
Influencia de la expropiación forzosa en la disponibilidad de terrenos para la ejecución de obras de modernización de regadíos
La evolución de la economía del país, ha hecho que los tipos de interés hayan
disminuido de manera continuada en los últimos años. El hecho de que la determinación del
valor de expropiación desde el año 2.007 se lleve a cabo mediante capitalización de rentas y
que, por lo tanto, el valor de indemnización dependa del tipo de interés, ha ocasionado un
efecto económico difícil para las partes beneficiarias en una expropiación.
En este trabajo se estudia la evolución de la normativa, se cuantifican los
resultados para el caso de una finca concreta de una explotación de algodón de regadío en
el valle del Guadalquivir y se analizan los resultados.
En el estudio puede observarse que en los últimos ocho años, el valor de mercado
de la tierra ha seguido una tendencia a la baja. Por el contrario, el valor de indemnización
por expropiación de la misma se ha disparado, lo que hace inviable a las comunidades de
regantes la participación en la modernización de regadíos, así como a la Administración la
aplicación del Plan Hidrológico Nacional o Plan Nacional de Regadíos.
Estas circunstancias han hecho que, en octubre de 2.015 (Ley de carreteras) y
noviembre de 2.015 (Texto refundido de Ley de Suelo), la legislación haya intentado paliar la
situación, aunque sigue siendo insuficiente. Por ello se proponen algunas medidas a modo
de conclusión al final del trabajo.The evolution of the country's economy has made that interest rates have decreased
continuously in recent years. The fact that since the year 2007 the determination of the value
of expropriation is being carried out through revenue capitalization, in which the
indemnification value depends on the interest rate, has caused a difficult economic impact in
the recipient parties of an expropriation.
In this paper we study the evolution of the expropriation regulations as well as the
assessment of the amount of money corresponding to the expropriation of a farm dedicated
the production of cotton in the Guadalquivir valley.
In the study it can be seen that over the last eight years the market value of the land
has followed a downward trend. On the other hand, the value of compensation for land expropriation has been triggered, making infeasible to the irrigation communities their
participation in the modernization of the irrigation systems and hinders the Administration the
implementation of the National Hydrological Plan or the National Irrigation Plan.
These circumstances have led the Government to try to alleviate the situation with new
regulations (road act of October 2015 and revised text of law of soil of November 2015)
which remain insufficient. Therefore some legislative proposals are given as conclusions at
the end of this work
Los drones a la luz del Derecho Internacional Humanitario (DIH)
Desde hace décadas se utilizan los drones como un instrumento más para ejecutar operaciones de
diverso tipo que, incluso, pueden implicar el uso de la fuerza letal. Con frecuencia, el recurso a los drones armados ha sido criticado por supuestas violaciones del Derecho internacional humanitario (DIH). El presente estudio analiza, por tanto, el recurso a unas armas tan criticadas como los drones a la luz, en particular, de los principios básicos del DIH de precaución, distinción y proporcionalidad. El objetivo es demostrar que, pese a su mala fama atribuida por los medios de comunicación, los drones armados respetan el DIH precisamente en atención a los tres principios mencionados.It is decades that States use drones as instruments to fulfil their operations of different kind, from patrolling to the use of lethal armed force. Frequently the use of armed drones has been criticised (and it is still) for alleged violations of International Humanitarian Law (IHL). Thus, this work analyses the use of –sometimes much
condemned by Medias– armed drones, especially in the light of precautionary, distinction, and proportionality IHL principles. The aim is to demonstrate that, despite their bad reputation, armed drones respect IHL under those three basic principles cited above
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