4,226 research outputs found
Effects of Orientations, Aspect Ratios, Pavement Materials and Vegetation Elements on Thermal Stress inside Typical Urban Canyons
The analysis of local climate conditions to test artificial urban boundaries and related climate hazards through modelling tools should become a common practice to inform public authorities about the benefits of planning alternatives. Different finishing materials and sheltering objects within urban canyons (UCs) can be tested, predicted and compared through quantitative and qualitative understanding of the relationships between the microclimatic environment and subjective thermal assessment. This process can work as support planning instrument in the early design phases as has been done in this study that aims to analyze the thermal stress within typical UCs of Bilbao (Spain) in summertime through the evaluation of Physiologically Equivalent Temperature using ENVI-met. The UCs are characterized by different orientations, height-to-width aspect ratios, pavement materials, trees’ dimensions and planting pattern. Firstly, the current situation was analyzed; secondly, the effects of asphalt and red brick stones as streets’ pavement materials were compared; thirdly, the benefits of vegetation elements were tested. The analysis demonstrated that orientation and aspect ratio strongly affect the magnitude and duration of the thermal peaks at pedestrian level; while the vegetation elements improve the thermal comfort up to two thermophysiological assessment classes. The outcomes of this study, were transferred and visualized into green planning recommendations for new and consolidated urban areas in Bilbao.The work leading to these results has received funding from COST Action TU0902, the European Community’s Seventh Framework Programme under Grant Agreement No. 308497, Project RAMSES—Reconciling Adaptation, Mitigation and Sustainable Development for Cities (2012–2017) and Diputación Foral de Bizkaia Exp. 6-12-TK-2010-0027, Project SICURB-ITS- Desarrollo de Sistemas para el análisis de la Contaminación atmosférica en zonas URBanas integrados en ITS (2010–2011)
Patrón temporal de movimientos del mero Epinephelus morio en la plataforma continental norte de la Península de Yucatán, México
Los movimientos estacionales del mero Epinephelus morio en la plataforma continental de Yucatán, son un elemento muy sensible en el manejo de la pesquería de este recurso que actualmente se encuentra sobreexplotado. En este trabajo se estima el patrón de movimientos de la población utilizando un modelo dinámico espacial. Se estimaron tasas de flujo de individuos entre áreas adyacentes considerando explícitamente la estructura de la población (juveniles, preadultos y adultos). El modelo fue aplicado utilizando información de captura por unidad de esfuerzo y distribuciones de frecuencias de longitud de la flota mediana mexicana que operó en la zona durante 1973, correspondiente a la época de las más altas capturas históricas. Se consideró capturabilidad variable con la talla, tiempo y zona así como mortalidad natural variable con la edad. Los resultados muestran patrones temporales de movimientos diferenciados por sector de población. Movimientos asociados a concentraciones de adultos fueron encontrados entre invierno y primavera en el centro y oriente de la plataforma continental, en profundidades de 35 a 60 m, mientras que el movimiento de los preadultos y juveniles fue en sentido contrario dirigiéndose hacia zonas más someras. En primavera-verano la población se desplaza hacia la zona occidental de la plataforma continental. Se detectó una mayor dinámica en adultos que en juveniles, sin embargo, se encontraron movimientos importantes de juveniles hacia el norte de la plataforma continental y frente a las zonas de Dzilam de Bravo-Río Lagartos. Los resultados muestran la importancia de esta información en la orientación de medidas de manejo como la exploración de áreas marinas protegidas o zonas de exclusión a la pesca que permitan la recuperación de la población
Bioremediation and biovalorisation of olive-mill wastes
Olive-mill wastes are produced by the industry of olive oil production, which is a very important economic activity, particularly for Spain, Italy and Greece, leading to a large environmental problem of current concern in the Mediterranean basin. There is as yet no accepted treatment method for all the wastes generated during olive oil production, mainly due to technical and economical limitations but also the scattered nature of olive mills across the Mediterranean basin. The production of virgin olive oil is expanding worldwide, which will lead to even larger amounts of olive-mill waste, unless new treatment and valorisation technologies are devised. These are encouraged by the trend of current environmental policies, which favour protocols that include valorisation of the waste. This makes biological treatments of particular interest. Thus, research into different biodegradation options for olive-mill wastes and the development of new bioremediation technologies and/or strategies, as well as the valorisation of microbial biotechnology, are all currently needed. This review, whilst presenting a general overview, focus critically on the most significant recent advances in the various types of biological treatments, the bioremediation technology most commonly applied and the valorisation options, which together will form the pillar for future developments within this fiel
Numerical model of the inhomogeneous scattering by the human lens
We present in this work a numerical model for characterizing the scattering properties of the human lens. After analyzing the scattering properties of two main scattering particles actually described in the literature through FEM (finite element method) simulations, we have modified a Monte Carlo''s bulk scattering algorithm for computing ray scattering in non-sequential ray tracing. We have implemented this ray scattering algorithm in a layered model of the human lens in order to calculate the scattering properties of the whole lens. We have tested our algorithm by simulating the classic experiment carried out by Van der Berg et al for measuring "in vitro" the angular distribution of forward scattered light by the human lens. The results show the ability of our model to simulate accurately the scattering properties of the human lens. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen
Corvina plateada (Cynoscion nothus): analisis de edad y crecimiento por metodos de frecuencias de longitud; Silver seatrout (Cynoscion nothus): age and growth analysis using length-based methods
Voltage dip generator for testing wind turbines connected to electrical networks
This paper describes a new voltage dip generator that allows the shape of the time profile of the voltage generated to be configured. The use of this device as a tool to test the fault ride-through capability of wind turbines connected to the electricity grid can provide some remarkable benefits: First, this system offers the possibility of adapting the main features of the time–voltage profile generated (dip depth, dip duration, the ramp slope during the recovery process after clearing fault, etc.) to the specific requirements set forth by the grid operation codes, in accordance with different network electrical systems standards. Second, another remarkable ability of this system is to provide sinusoidal voltage and current wave forms during the overall testing process without the presence of harmonic components. This is made possible by the absence of electronic converters. Finally, the paper includes results and a discussion on the experimental data obtained with the use of a reduced size laboratory prototype that was constructed to validate the operating features of this new device
Measurement driven quantum evolution
We study the problem of mapping an unknown mixed quantum state onto a known
pure state without the use of unitary transformations. This is achieved with
the help of sequential measurements of two non-commuting observables only. We
show that the overall success probability is maximized in the case of measuring
two observables whose eigenstates define mutually unbiased bases. We find that
for this optimal case the success probability quickly converges to unity as the
number of measurement processes increases and that it is almost independent of
the initial state. In particular, we show that to guarantee a success
probability close to one the number of consecutive measurements must be larger
than the dimension of the Hilbert space. We connect these results to quantum
copying, quantum deleting and entanglement generation.Comment: 7 pages, 1 figur
Second law analysis of two-stage vapour compression refrigeration plants
[EN] This paper describes a Second Law Analysis based on experimental data of a two-stage vapour compression facility driven by a compound compressor for medium and low-capacity refrigeration applications, which operates with the most usual inter-stage configurations (direct liquid injection and subcooler). The experimental analysis is performed for an evaporating temperature range between 36 degrees C and 20 degrees C and for a condensing temperature range between 30 degrees C and 47 degrees C using the refrigerant R-404A. The final results are compared with energy analysis from previous works. Additionally, a new criterion of equivalence between the simple vapour compression cycle and the two-stage compression cycle is given.The authors are indebted to the Spanish Ministry of Education and Science
(CTM2008-06468-C02-02/TECNO) and to the Spanish Ministry of the Environment and
Rural and Marine Affairs (200800050084716) for their economic support to this work.Torrella Alcaraz, E.; Llopis, R.; Cabello, R.; Sanchez, D.; Larumbe, J. (2010). Second law analysis of two-stage vapour compression refrigeration plants. International Journal of Exergy. 7(6):641-653. https://doi.org/10.1504/IJEX.2010.035512S6416537
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