410 research outputs found

    Thermoecological cost of electricity, heat and cold generated in a trigeneration module fuelled with selected fossil and renewable fuels

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    The paper presents a thermoecological evaluation of a trigeneration module based on an Internal Combustion Engine fuelled with selected fuels of various origin: domestic/mixed-origin natural gas, CMM (coal mine methane) and biogas. The generated products comprise: electric energy, heat available in hot water and cold generated in an absorption chiller. Transformations of energy and exergy in the trigeneration module have been analysed, and the TEC (thermoecological cost) of the products has been determined. The decomposition of TEC into the cost of resources, the contribution of process irreversibility and the equivalent cost of noxious substances has been shown. The chosen gaseous fuels reflect four different cases: a fossil, non-renewable resource (1 – domestic, 2 – mixed origin) 3 – a by-product from the extraction of a fossil resource and 4 – a renewable resource. It has been demonstrated how the TEC of final products depends on the chosen resource, on the process irreversibility, and on the waste contribution. TEC of electricity produced in the trigeneration module varies from 0.30 (biomass syngas) to 3.11 (mixed origin natural gas), and the TEC of the generated heat and cold varies from 0.61 to 6.46 (heat) and 3.37 and 35.5 (cold) accordingly

    Tratamiento quirúrgico de las pérdidas de sustancia cutánea en el carpo, mediante colgajos libres vascularizados en el perro

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    En el presente trabajo se describe la técnica de la transposición libre microquirúrgica de colgajos de piel, así como los resultados de dicha transferencia, realizada en cinco perros.At the present research the techníque of the free transposition mícrosurgícal of flaps is described, as well as the results from the performed transference in five dogs

    La neumografia retroperitonealdirecta frente a otras técnicas radioloógicas de contraste negativo para la visualización del riñón en la especie canina

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    Proponemos el uso de una nueva técnica radiológica para la visualización de los riñones, la neumografia retroperitoneal directa, una técnica sencilla y segura, en la que se obtienen imágenes de gran calidad y que nos permite visualizar selectivamente uno o ambos riñones a partir de un único punto de insuflación. Desarrollarnos un modelo experimental en el que se compara esta técnica con la neumoperitoneografía y la neumografía retroperítoneal presacra, valorando la calidad de las imágenes, el grado de dificultad y la seguridad de las mismas.The use of a new radiological technique for kidneys visualization isproposed, the direct retroperitoneal pneumograpby; an easy and safe technique which gives high qua lity images, visualizing selectively one or both kidneys starting from only one insufflation point. An experimental model of comparison between the direct retroperitoneal pneumograpby, the pneumoperitoneograpby and the pararectal retroperitoneal neumography is carried out; estimating the images qua lity, the difficulty level and the security ofthis techniques

    Sustainability reporting in view of the European sustainable finance taxonomy: Is the financial sector ready to disclose circular economy?

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    The European sustainable finance taxonomy requires financial and nonfinancial companies to provide investors with information about the environmental performance of their assets and economic activities. For financial institutions, making socially and environmentally responsible investments visible through a common label that guarantees specific standards for the entire European Union is crucial. Against this background, this study analyzes the evolution of sustainability reporting practices and their assurance in a sample of European financial institutions. To this end, we used a double qualitative methodological approach, based on (a) an external analysis of nonfinancial information and its relationship with the main economic-financial variables of the sample companies, and (b) a case study of a bank carried out through semi-structured interviews. This study provides an external measurement analysis of nonfinancial information in entities from different countries, which can contribute to broadening the scope and level of sustainability and circular economy accountability

    Irrigation from the Sixties: Flumen-Monegros

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    53 Pags.- Tabls.- Maps.In arid and semiarid areas, agricultural land use is mainly restricted, in the first place, by the availability of water for crop growth. The transformation to irrigation of about 600 000 ha in the Ebro Valley has led to high increases in yield and in diversity of crops. After the Spanish Civil War (1936-39), which was followed by II World War, the Spanish food production system was heavily disrupted and food shortages appeared. This put high pressure on the development of new irrigated schemes which had been planned many years ago. In the Flumen-Monegros area, the technology available in the late fifties was based on flood-irrigation systems, with no previous soil studies, an empirical land evaluation, no control of saltinization risk and, finally, levelling without topsoil preservation. The extension of salinity and/or sodicity-affected soils in the Ebro Valley (IRYDA, 1977) was 200 000 ha, from which 160 000 were located in Aragon, mainly in Bardenas, Cinca and Flumen-Monegros area. But Alberto et al. (1984) reckron this data in 300 000 ha. As a result of these studies, ILACO (1975) designed two experimental drainage plots. Although the existence of salt-affected soils was known, information about the extent, location and general functioning at landscape level of those soils was lacking in the area. Some of the problems related to land use and soil management which are present now in the area or can be expected in the near future are:- Salinity-Sodicity: Diagnosis, monitoring and rehabilitation of salt-affected soils. - Soil structural degradation and surface crust formation. - Need for improved efficiency in water use: irrigation technology, water reuse, ... - Control of drainage-system degradation: open-air drains as well as underground drains. Several approaches at different scales have been adopted to work on these issues. Satellite images have been used to monitor land use and its temporal variability. Classical soil mapping at 1: 100000 level have been performed; in addition various detailed studies have been undertaken in model areas using the electromagnetic and four electrode sensors, micromorphological techniques, scanning electronic microscopy, and land evaluation procedures. The results have been presented in several papers: about salinity-sodicity trends in the Flumen sector (Herrero, 1987); about parameters related to water behaviour (Aragues, 1986); about soil porosity in plough horizons (Rodriguez-Ochoa, 1998); about translocation of solid materials (Rodriguez-Ochoa, et al. 1989; Porta and Rodriguez-Ochoa, 1991; Rodriguez-Ochoa, 1998); about degradation of underground drainage systems by mineral siltation (Herrero et al. 1989; Rodriguez-Ochoa, et al. 1989; Munoz, 1991; RodriguezOchoa, 1998).Other studies performed in the area include: Soil-vegetation relationships (Herrero, 1981); laboratory trials with different amendments in the drainage trench infilling material (Porta et al. 1996); dispersive processes because of soil structural instability (Amezketa and Aragues, 1990; Aragues and Amezketa, 1991; Amezketa and Aragues, 1995) and degradation of the hydraulic conductivity of soils (Amezketa and Aragues, 1989; Aragues and Amezketa, 1991; Amezketa and Aragues, 1995). The trip to the Flumen-Monegros area undertakes some of these points, and the stops are located in some of the main soil units. Discussion will be centered on aspects of soil genesis, classification and mapping, land use and soil conservation.Peer reviewe

    Gyre and gimble: a maximum-likelihood replacement for Patterson correlation refinement.

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    Descriptions are given of the maximum-likelihood gyre method implemented in Phaser for optimizing the orientation and relative position of rigid-body fragments of a model after the orientation of the model has been identified, but before the model has been positioned in the unit cell, and also the related gimble method for the refinement of rigid-body fragments of the model after positioning. Gyre refinement helps to lower the root-mean-square atomic displacements between model and target molecular-replacement solutions for the test case of antibody Fab(26-10) and improves structure solution with ARCIMBOLDO_SHREDDER

    A conserved filamentous assembly underlies the structure of the meiotic chromosome axis.

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    The meiotic chromosome axis plays key roles in meiotic chromosome organization and recombination, yet the underlying protein components of this structure are highly diverged. Here, we show that 'axis core proteins' from budding yeast (Red1), mammals (SYCP2/SYCP3), and plants (ASY3/ASY4) are evolutionarily related and play equivalent roles in chromosome axis assembly. We first identify 'closure motifs' in each complex that recruit meiotic HORMADs, the master regulators of meiotic recombination. We next find that axis core proteins form homotetrameric (Red1) or heterotetrameric (SYCP2:SYCP3 and ASY3:ASY4) coiled-coil assemblies that further oligomerize into micron-length filaments. Thus, the meiotic chromosome axis core in fungi, mammals, and plants shares a common molecular architecture, and likely also plays conserved roles in meiotic chromosome axis assembly and recombination control

    Exergy assessment and exergy cost analysis of a renewable-based and hybrid trigeneration scheme for domestic water and energy supply

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    Exergy and exergy cost analyses are proposed as complementary methods for the assessment and better understanding of the efficiency of a hybrid trigeneration system based on renewable energy sources. The system combines photovoltaic/thermal collectors, an evacuated tube collector and a wind turbine and produces electricity, sanitary hot water and desalted fresh water for a single family house. The system includes two desalination technologies (reverse osmosis and membrane distillation) that consume power and heat respectively, and two kinds of energy storage devices (a hot water tank and two lead-acid batteries). The assessment is based on simulations developed by using TRNSYS software. As a first level of detail, exergy analysis is applied in ten-minute basis to selected plant components. As a second level of detail, it is proposed to apply exergy-based indicators that summarize the system behavior during a longer period of time (monthly basis). By using aggregated values, exergy accumulation terms become negligible, what allows applying symbolic thermoeconomics to calculate exergy cost and to analyze in depth the process of cost formation. The system has an exergy efficiency of 7.76% (6.68 due to electricity, 0.33 due to fresh water and 0.75 due to sanitary hot water)
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