22 resultados para Environmental effect
Resumo:
Son numerosos los expertos que predicen que hasta pasado 2050 no se utilizarán masivamente las energías de origen renovable, y que por tanto se mantendrá la emisión de dióxido de carbono de forma incontrolada. Entre tanto, y previendo que este tipo de uso se mantenga hasta un horizonte temporal aún más lejano, la captura, concentración y secuestro o reutilización de dióxido de carbono es y será una de las principales soluciones a implantar para paliar el problema medioambiental causado. Sin embargo, las tecnologías existentes y en desarrollo de captura y concentración de este tipo de gas, presentan dos limitaciones: las grandes cantidades de energía que consumen y los grandes volúmenes de sustancias potencialmente dañinas para el medioambiente que producen durante su funcionamiento. Ambas razones hacen que no sean atractivas para su implantación y uso de forma extensiva. La solución planteada en la presente tesis doctoral se caracteriza por la ausencia de residuos producidos en la operación de captura y concentración del dióxido de carbono, por no utilizar substancias químicas y físicas habituales en las técnicas actuales, por disminuir los consumos energéticos al carecer de sistemas móviles y por evitar la regeneración química y física de los materiales utilizados en la actualidad. Así mismo, plantea grandes retos a futuras innovaciones sobre la idea propuesta que busquen fundamentalmente la disminución de la energía utilizada durante su funcionamiento y la optimización de sus componentes principales. Para conseguir el objetivo antes citado, la presente tesis doctoral, una vez establecido el planteamiento del problema al que se busca solución (capítulo 1), del estudio de las técnicas de separación de gases atmosféricos utilizadas en la actualidad, así como del de los sistemas fundamentales de las instalaciones de captura y concentración del dióxido de carbono (capítulo 2) y tras una definición del marco conceptual y teórico (capítulo 3), aborda el diseño de un prototipo de ionización fotónica de los gases atmosféricos para su posterior separación electrostática, a partir del estudio, adaptación y mejora del funcionamiento de los sistemas de espectrometría de masas. Se diseñarán y desarrollarán los sistemas básicos de fotoionización, mediante el uso de fuentes de fotones coherentes, y los de separación electrostática (capítulo 4), en que se basa el funcionamiento de este sistema de separación de gases atmosféricos y de captura y concentración de dióxido de carbono para construir un prototipo a nivel laboratorio. Posteriormente, en el capítulo 5, serán probados utilizando una matriz experimental que cubra los rangos de funcionamiento previstos y aporte suficientes datos experimentales para corregir y desarrollar el marco teórico real, y con los que se pueda establecer y corregir un modelo físico– matemático de simulación (capítulo 6) aplicable a la unidad en su conjunto. Finalmente, debido a la utilización de unidades de ionización fotónica, sistemas láseres intensos y sistemas eléctricos de gran potencia, es preciso analizar el riesgo biológico a las personas y al medioambiente debido al impacto de la radiación electromagnética producida (capítulo 7), minimizando su impacto y cumpliendo con la legislación vigente. En el capítulo 8 se planteará un diseño escalable a tamaño piloto de la nueva tecnología propuesta y sus principales modos de funcionamiento, así como un análisis de viabilidad económica. Como consecuencia de la tesis doctoral propuesta y del desarrollo de la unidad de separación atmosférica y de captura y concentración de dióxido de carbono, surgen diversas posibilidades de estudio que pueden ser objeto de nuevas tesis doctorales y de futuros desarrollos de ingeniería. El capítulo 9 tratará de incidir en estos aspectos indicando líneas de investigación para futuras tesis y desarrollos industriales. ABSTRACT A large number of experts predict that until at least 2050 renewable energy sources will not be massively used, and for that reason, current Primary Energy sources based on extensive use of fossil fuel will be used maintaining out of control emissions, Carbon Dioxide above all. Meanwhile, under this scenario and considering its extension until at least 2050, Carbon Capture, Concentration, Storage and/or Reuse is and will be one of the main solutions to minimise Greenhouse Gasses environmental effect. But, current Carbon Capture and Storage technology state of development has two main problems: it is a too large energy consuming technology and during normal use it produces a large volume of environmentally dangerous substances. Both reasons are limiting its development and its extensive use. This Ph Degree Thesis document proposes a solution to get the expected effect using a new atmospheric gasses separation system with the following characteristics: absence of wastes produced, it needs no chemical and/or physical substances during its operation, it reduces to minimum the internal energy consumptions due to absence of mobile equipment and it does not need any chemical and/or physical regeneration of substances. This system is beyond the State of the Art of current technology development. Additionally, the proposed solution raises huge challenges for future innovations of the proposed idea finding radical reduction of internal energy consumption during functioning, as well as regarding optimisation of main components, systems and modes of operation. To achieve this target, once established the main problem, main challenge and potential solving solutions (Chapter 1), it is established an initial starting point fixing the Atmospheric Gasses Separation and Carbon Capture and Storage developments (Chapter 2), as well as it will be defined the theoretical and basic model, including existing and potential new governing laws and mathematical formulas to control its system functioning (Chapter 3), this document will deal with the design of an installation of an operating system based on photonic ionization of atmospheric gasses to be separated in a later separation system based on the application of electrostatic fields. It will be developed a basic atmospheric gasses ionization prototype based on intense radioactive sources capable to ionize gasses by coherent photonic radiation, and a basic design of electrostatic separation system (Chapter 4). Both basic designs are the core of the proposed technology that separates Atmospheric Gasses and captures and concentrates Carbon Dioxide. Chapter 5 will includes experimental results obtained from an experimental testing matrix covering expected prototype functioning regimes. With the obtained experimental data, theoretical model will be corrected and improved to act as the real physical and mathematical model capable to simulate real system function (Chapter 6). Finally, it is necessary to assess potential biological risk to public and environment due to the proposed use of units of intense energy photonic ionization, by laser beams or by non–coherent sources and large electromagnetic systems with high energy consumption. It is necessary to know the impact in terms of and electromagnetic radiation taking into account National Legislation (Chapter 7). On Chapter 8, an up scaled pilot plant will be established covering main functioning modes and an economic feasibility assessment. As a consequence of this PhD Thesis, a new field of potential researches and new PhD Thesis are opened, as well as future engineering and industrial developments (Chapter 9).
Resumo:
This study examines the seed dispersal spectrum of the tropical dry forests of Southern Ecuador, in an effort to contribute to the knowledge of the complex dynamics of tropical dry forests. Seed dispersal spectrum was described for a total number of 160 species. Relationships of dispersal syndromes with plant growth form and climatic seasonality were explored. For a subset of 97 species, we determined whether dispersal spectrum changes when species abundance, in addition to species number, is taken into account. The same subset was used to relate dispersal syndromes with the environmental conditions. Zoochorous species dominated in the studied community. When considering the individual abundance of each species, however, anemochory was the prevalent dispersal syndrome. We found a significant difference in the frequency of dispersal syndromes among plant growth forms, with epizoochory only occurring in shrub species. The dispersal spectrum was dependent on climatic seasonality. The largest proportion of anemochorous species fructified during the dry season, while zoochorous diaspores dominated during the rainy season. A fourth-corner analysis indicated that the seed dispersal spectrum of Southern Ecuador dry forests is controlled by environmental conditions such as annual precipitation, annual temperature range or topography. Our results suggest that spatio-temporal changes in the environmental conditions may affect important ecological processes for dispersal. Thus, the predominance of one syndrome or another may depend on the spatial variation of environmental conditions.
Resumo:
This paper reports the effects produced on the organisms of the soil (plants, invertebrates and microorganisms), after the application of two types of poultry manure (sawdust and straw bed) on an agricultural land. The test was made using a terrestrial microcosm, Multi-Species Soil System (MS3) developed in INIA. There was no difference in the germination for any of the three species of plants considered in the study. The biomass was increased in the wheat (Triticum aestivum) coming from ground treated with both kinds of poultry manure. Oilseed rape (Brasica rapa) was not affected and regarding vetch (Vicia sativa) only straw poultry manure showed significant difference. For length only Vicia sativa was affected showing a reduction when straw was exposed to poultry manure. When the effect on invertebrates was studied, we observed a reduction in the number of worms during the test, especially from the ground control (13.7%), higher than in the ground with sawdust poultry manure (6.7%), whereas in the ground with straw poultry manure, there was no reduction. The biomass was affected and at the end of the test it was observed that while the reduction of worms in the ground control was about 48%, the number of those that were in the ground with sawdust poultry manure or straw poultry manure decreased by 41% and 22% respectively. Finally, the effects on microorganisms showed that the enzymatic activities: dehydrogenase (DH) and phosphatase and basal respiration rate increased at the beginning of the test, and the differences were statistically significant compared with the values of the control group. During the test, all these parameters decreased (except DH activities) but they were always higher than in the ground control. This is why it is possible to deduce that the contribution of poultry manure caused an improvement in the conditions of fertilization and also for the soil.
Resumo:
Introducing cover crops (CC) interspersed with intensively fertilized crops in rotation has the potential to reduce nitrate leaching. This paper evaluates various strategies involving CC between maize and compares the economic and environmental results with respect to a typical maize?fallow rotation. The comparison is performed through stochastic (Monte-Carlo) simulation models of farms? profits using probability distribution functions (pdfs) of yield and N fertilizer saving fitted with data collected from various field trials and pdfs of crop prices and the cost of fertilizer fitted from statistical sources. Stochastic dominance relationships are obtained to rank the most profitable strategies from a farm financial perspective. A two-criterion comparison scheme is proposed to rank alternative strategies based on farm profit and nitrate leaching levels, taking the baseline scenario as the maize?fallow rotation. The results show that when CC biomass is sold as forage instead of keeping it in the soil, greater profit and less leaching of nitrates are achieved than in the baseline scenario. While the fertilizer saving will be lower if CC is sold than if it is kept in the soil, the revenue obtained from the sale of the CC compensates for the reduced fertilizer savings. The results show that CC would perhaps provide a double dividend of greater profit and reduced nitrate leaching in intensive irrigated cropping systems in Mediterranean regions.
Resumo:
Los montes Mediterráneos han experimentado múltiples cambios en las últimas décadas (tanto en clima como en usos), lo que ha conducido a variaciones en la distribución de especies. El aumento previsto de las temperaturas medias junto con la mayor variabilidad intra e inter anual en cuanto a la ocurrencia de eventos extremos o disturbios naturales (como periodos prolongados de sequía, olas de frío o calor, incendios forestales o vendavales) pueden dañar significativamente al regenerado, llevándolo hasta la muerte, y jugando un papel decisivo en la composición de especies y en la dinámica del monte. La amplitud ecológica de muchas especies forestales puede verse afectada, de forma que se esperan cambios en sus nichos actuales de regeneración. Sin embargo, la migración latitudinal de las especies en busca de mejores condiciones, podría ser una explicación demasiado simplista de un proceso mucho más complejo de interacción entre la temperatura y la precipitación, que afectaría a cada especie de un modo distinto. En este sentido tanto la capacidad de adaptación al estrés ambiental de una determinada especie, así como su habilidad para competir por los recursos limitados, podría significar variaciones dentro de una comunidad. Las características fisiológicas y morfológicas propias de cada especie se encuentran fuertemente relacionadas con el lugar donde cada una puede surgir, qué especies pueden convivir y como éstas responden a las condiciones ambientales. En este sentido, el conocimiento sobre las distintas respuestas ecofisiológicas observadas ante cambios ambientales puede ser fundamentales para la predicción de variaciones en la distribución de especies, composición de la comunidad y productividad del monte ante el cambio global. En esta tesis investigamos el grado de tolerancia y sensibilidad que cada una de las tres especies de estudio, coexistentes en el interior peninsular ibérico (Pinus pinea, Quercus ilex y Juniperus oxycedrus), muestra ante los factores abióticos de estrés típicos de la región Mediterránea. Nuestro trabajo se ha basado en la definición del nicho óptimo fisiológico para el regenerado de cada especie a través de la investigación en profundidad del efecto de la sequía, la temperatura y el ambiente lumínico. Para ello, hemos desarrollado un modelo de predicción de la tasa de asimilación de carbono que nos ha permitido identificar las condiciones óptimas ambientales donde el regenerado de cada especie podría establecerse con mayor facilidad. En apoyo a este trabajo y con la idea de estudiar el efecto de la sequía a nivel de toda la planta hemos desarrollado un experimento paralelo en invernadero. Aquí se han aplicado dos regímenes hídricos para estudiar las características fisiológicas y morfológicas de cada especie, sobre todo a nivel de raíz y crecimiento del tallo, y relacionarlas con las diferentes estrategias en el uso del agua de las especies. Por último, hemos estudiado los patrones de aclimatación y desaclimatación al frio de cada especie, identificando los periodos de sensibilidad a heladas, así como cuellos de botella donde la competencia entre especies podría surgir. A pesar de que el pino piñonero ha sido la especie objeto de la gestión de estas masas durante siglos, actualmente se encuentra en la posición más desfavorable para combatir el cambio global, presentado el nicho fisiológico más estrecho de las tres especies. La encina sin embargo, ha resultado ser la especie mejor cualificada para afrontar este cambio, seguida muy de cerca por el enebro. Nuestros resultados sugieren una posible expansión en el rango de distribución de la encina, un aumento en la presencia del enebro y una disminución progresiva del pino piñonero a medio plazo en estas masas. ABSTRACT Mediterranean forests have undergone multiple changes over the last decades (in both climate and land use), which have lead to variations in the distribution of species. The expected increase in mean annual temperature together with the greater inter and intra-annual variability in extreme events and disturbances occurrence (such as prolonged drought periods, cold or heat waves, wildfires or strong winds) can significantly damage natural regeneration, up to causing death, playing a decisive role on species composition and forest dynamics. The ecological amplitude for adaptation of many species can be affected in such a way that changes in the current regeneration niches of many species are expected. However, the forecasted poleward migration of species seeking better conditions could be an oversimplification of what is a more complex phenomenon of interactions among temperature and precipitation, that would affect different species in different ways. In this regard, either the ability to adapt to environmental stresses or to compete for limited resources of a single species in a mixed forest could lead to variations within a community. The ecophysiological and morphological traits specific to each species are strongly related to the place where each species can emerge, which species can coexist, and how they respond to environmental conditions. In this regard, the understanding of the ecophysiological responses observed against changes in environmental conditions can be essential for predicting variations in species distribution, community composition, and forest productivity in the context of global change. In this thesis we investigated the degree of tolerance and sensitivity that each of the three studied species, co-occurring in central of the Iberian Peninsula (Pinus pinea, Quercus ilex and Juniperus oxycedrus), show against the typical abiotic stress factors in the Mediterranean region. Our work is based on the optimal physiological niche for regeneration of each species through in-depth research on the effect of drought, temperature and light environment. For this purpose, we developed a model to predict the carbon assimilation rate which allows us to identify the optimal environmental conditions where regeneration from each species could establish itself more easily. To obtain a better understanding about the effect of low temperature on regeneration, we studied the acclimation and deacclimation patterns to cold of each species, identifying period of frost sensitivity, as well as bottlenecks where competition between species can arise. Finally, to support our results about the effect of water availabilty, we conducted a greenhouse experiment with a view of studying the drought effect at the whole plant level. Here, two watering regimes were applied in order to study the physiological and morphological traits of each species, mainly at the level of the root system and stem growth, and so relate them to the different water use strategies of the species. Despite the fact that stone pine has been the target species for centuries, nowadays this species is in the most unfavorable position to cope with climate change. Holm oak, however, resulted the species that is best adapted to tolerate the predicted changes, followed closely by prickly juniper. Our results suggest a feasible expansion of the distribution range in holm oak, an increase in the prickly juniper presence and a progressive decreasing of stone pine presence in the medium term in these stone pine-holm oak-prickly juniper mixed forests.
Resumo:
Researchers in ecology commonly use multivariate analyses (e.g. redundancy analysis, canonical correspondence analysis, Mantel correlation, multivariate analysis of variance) to interpret patterns in biological data and relate these patterns to environmental predictors. There has been, however, little recognition of the errors associated with biological data and the influence that these may have on predictions derived from ecological hypotheses. We present a permutational method that assesses the effects of taxonomic uncertainty on the multivariate analyses typically used in the analysis of ecological data. The procedure is based on iterative randomizations that randomly re-assign non identified species in each site to any of the other species found in the remaining sites. After each re-assignment of species identities, the multivariate method at stake is run and a parameter of interest is calculated. Consequently, one can estimate a range of plausible values for the parameter of interest under different scenarios of re-assigned species identities. We demonstrate the use of our approach in the calculation of two parameters with an example involving tropical tree species from western Amazonia: 1) the Mantel correlation between compositional similarity and environmental distances between pairs of sites, and; 2) the variance explained by environmental predictors in redundancy analysis (RDA). We also investigated the effects of increasing taxonomic uncertainty (i.e. number of unidentified species), and the taxonomic resolution at which morphospecies are determined (genus-resolution, family-resolution, or fully undetermined species) on the uncertainty range of these parameters. To achieve this, we performed simulations on a tree dataset from southern Mexico by randomly selecting a portion of the species contained in the dataset and classifying them as unidentified at each level of decreasing taxonomic resolution. An analysis of covariance showed that both taxonomic uncertainty and resolution significantly influence the uncertainty range of the resulting parameters. Increasing taxonomic uncertainty expands our uncertainty of the parameters estimated both in the Mantel test and RDA. The effects of increasing taxonomic resolution, however, are not as evident. The method presented in this study improves the traditional approaches to study compositional change in ecological communities by accounting for some of the uncertainty inherent to biological data. We hope that this approach can be routinely used to estimate any parameter of interest obtained from compositional data tables when faced with taxonomic uncertainty.
Resumo:
The research work as presented in this article covers the design of detached breakwaters since they constitute a type of coastal defence work with which to combat many of the erosion problems found on beaches in a stable, sustainable fashion. The main aim of this work is to formulate a functional and environmental (but not structural) design method, enabling the fundamental characteristics of a detached breakwater to be defined as a function of the effect it is wished to induce on the coast, and taking into account variables of a different nature (climate, geomorphology and geometry) influencing the changes the shoreline undergoes after its construction. With this article, it is intended to submit the final result of the investigation undertaken, applying the detached breakwater design method as developed to solving a practical case. Thus it may be shown how the method enables a detached breakwater’s geometric pre-sizing to be tackled at a place on the coast with certain climate, geomorphology and littoral dynamic characteristics, first setting the final state of equilibrium it is wanted to obtain therein after its construction.
Resumo:
Adding Zn improves crop growth, increases seed yield and also positively affects nutritional quality. After Zn fertilization, there is normally a period of several years in which residual effects provide an adequate supply of Zn to successive crops. Immediately after the application of Zn sources water-soluble Zn slowly but continually decreases. Various factors, including time and moisture conditions, affect the aging process and modify the solubility of the metal in soil and therefore its availability. In previous experiments, we studied the residual effect of synthetic chelates, obtained that the amounts of potentially available Zn decreased in the second cropping year due to aging processes. The present study was undertaken to verify variations in the residual effects of applying four different synthetic Zn sources
Resumo:
La termografía infrarroja (TI) es una técnica no invasiva y de bajo coste que permite, con el simple acto de tomar una fotografía, el registro sin contacto de la energía que irradia el cuerpo humano (Akimov & Son’kin, 2011, Merla et al., 2005, Ng et al., 2009, Costello et al., 2012, Hildebrandt et al., 2010). Esta técnica comenzó a utilizarse en el ámbito médico en los años 60, pero debido a los malos resultados como herramienta diagnóstica y la falta de protocolos estandarizados (Head & Elliot, 2002), ésta se dejó de utilizar en detrimento de otras técnicas más precisas a nivel diagnóstico. No obstante, las mejoras tecnológicas de la TI en los últimos años han hecho posible un resurgimiento de la misma (Jiang et al., 2005, Vainer et al., 2005, Cheng et al., 2009, Spalding et al., 2011, Skala et al., 2012), abriendo el camino a nuevas aplicaciones no sólo centradas en el uso diagnóstico. Entre las nuevas aplicaciones, destacamos las que se desarrollan en el ámbito de la actividad física y el deporte, donde recientemente se ha demostrado que los nuevos avances con imágenes de alta resolución pueden proporcionar información muy interesante sobre el complejo sistema de termorregulación humana (Hildebrandt et al., 2010). Entre las nuevas aplicaciones destacan: la cuantificación de la asimilación de la carga de trabajo físico (Čoh & Širok, 2007), la valoración de la condición física (Chudecka et al., 2010, 2012, Akimov et al., 2009, 2011, Merla et al., 2010), la prevención y seguimiento de lesiones (Hildebrandt et al., 2010, 2012, Badža et al., 2012, Gómez Carmona, 2012) e incluso la detección de agujetas (Al-Nakhli et al., 2012). Bajo estas circunstancias, se acusa cada vez más la necesidad de ampliar el conocimiento sobre los factores que influyen en la aplicación de la TI en los seres humanos, así como la descripción de la respuesta de la temperatura de la piel (TP) en condiciones normales, y bajo la influencia de los diferentes tipos de ejercicio. Por consiguiente, este estudio presenta en una primera parte una revisión bibliográfica sobre los factores que afectan al uso de la TI en los seres humanos y una propuesta de clasificación de los mismos. Hemos analizado la fiabilidad del software Termotracker, así como su reproducibilidad de la temperatura de la piel en sujetos jóvenes, sanos y con normopeso. Finalmente, se analizó la respuesta térmica de la piel antes de un entrenamiento de resistencia, velocidad y fuerza, inmediatamente después y durante un período de recuperación de 8 horas. En cuanto a la revisión bibliográfica, hemos propuesto una clasificación para organizar los factores en tres grupos principales: los factores ambientales, individuales y técnicos. El análisis y descripción de estas influencias deben representar la base de nuevas investigaciones con el fin de utilizar la TI en las mejores condiciones. En cuanto a la reproducibilidad, los resultados mostraron valores excelentes para imágenes consecutivas, aunque la reproducibilidad de la TP disminuyó ligeramente con imágenes separadas por 24 horas, sobre todo en las zonas con valores más fríos (es decir, zonas distales y articulaciones). Las asimetrías térmicas (que normalmente se utilizan para seguir la evolución de zonas sobrecargadas o lesionadas) también mostraron excelentes resultados pero, en este caso, con mejores valores para las articulaciones y el zonas centrales (es decir, rodillas, tobillos, dorsales y pectorales) que las Zonas de Interés (ZDI) con valores medios más calientes (como los muslos e isquiotibiales). Los resultados de fiabilidad del software Termotracker fueron excelentes en todas las condiciones y parámetros. En el caso del estudio sobre los efectos de los entrenamientos de la velocidad resistencia y fuerza en la TP, los resultados muestran respuestas específicas según el tipo de entrenamiento, zona de interés, el momento de la evaluación y la función de las zonas analizadas. Los resultados mostraron que la mayoría de las ZDI musculares se mantuvieron significativamente más calientes 8 horas después del entrenamiento, lo que indica que el efecto del ejercicio sobre la TP perdura por lo menos 8 horas en la mayoría de zonas analizadas. La TI podría ser útil para cuantificar la asimilación y recuperación física después de una carga física de trabajo. Estos resultados podrían ser muy útiles para entender mejor el complejo sistema de termorregulación humano, y por lo tanto, para utilizar la TI de una manera más objetiva, precisa y profesional con visos a mejorar las nuevas aplicaciones termográficas en el sector de la actividad física y el deporte Infrared Thermography (IRT) is a safe, non-invasive and low-cost technique that allows the rapid and non-contact recording of the irradiated energy released from the body (Akimov & Son’kin, 2011; Merla et al., 2005; Ng et al., 2009; Costello et al., 2012; Hildebrandt et al., 2010). It has been used since the early 1960’s, but due to poor results as diagnostic tool and a lack of methodological standards and quality assurance (Head et al., 2002), it was rejected from the medical field. Nevertheless, the technological improvements of IRT in the last years have made possible a resurgence of this technique (Jiang et al., 2005; Vainer et al., 2005; Cheng et al., 2009; Spalding et al., 2011; Skala et al., 2012), paving the way to new applications not only focused on the diagnose usages. Among the new applications, we highlighted those in physical activity and sport fields, where it has been recently proven that a high resolution thermal images can provide us with interesting information about the complex thermoregulation system of the body (Hildebrandt et al., 2010), information than can be used as: training workload quantification (Čoh & Širok, 2007), fitness and performance conditions (Chudecka et al., 2010, 2012; Akimov et al., 2009, 2011; Merla et al., 2010; Arfaoui et al., 2012), prevention and monitoring of injuries (Hildebrandt et al., 2010, 2012; Badža et al., 2012, Gómez Carmona, 2012) and even detection of Delayed Onset Muscle Soreness – DOMS- (Al-Nakhli et al., 2012). Under this context, there is a relevant necessity to broaden the knowledge about factors influencing the application of IRT on humans, and to better explore and describe the thermal response of Skin Temperature (Tsk) in normal conditions, and under the influence of different types of exercise. Consequently, this study presents a literature review about factors affecting the application of IRT on human beings and a classification proposal about them. We analysed the reliability of the software Termotracker®, and also its reproducibility of Tsk on young, healthy and normal weight subjects. Finally, we examined the Tsk thermal response before an endurance, speed and strength training, immediately after and during an 8-hour recovery period. Concerning the literature review, we proposed a classification to organise the factors into three main groups: environmental, individual and technical factors. Thus, better exploring and describing these influence factors should represent the basis of further investigations in order to use IRT in the best and optimal conditions to improve its accuracy and results. Regarding the reproducibility results, the outcomes showed excellent values for consecutive images, but the reproducibility of Tsk slightly decreased with time, above all in the colder Regions of Interest (ROI) (i.e. distal and joint areas). The side-to-side differences (ΔT) (normally used to follow the evolution of some injured or overloaded ROI) also showed highly accurate results, but in this case with better values for joints and central ROI (i.e. Knee, Ankles, Dorsal and Pectoral) than the hottest muscle ROI (as Thigh or Hamstrings). The reliability results of the IRT software Termotracker® were excellent in all conditions and parameters. In the part of the study about the effects on Tsk of aerobic, speed and strength training, the results of Tsk demonstrated specific responses depending on the type of training, ROI, moment of the assessment and the function of the considered ROI. The results showed that most of muscular ROI maintained warmer significant Tsk 8 hours after the training, indicating that the effect of exercise on Tsk last at least 8 hours in most of ROI, as well as IRT could help to quantify the recovery status of the athlete as workload assimilation indicator. Those results could be very useful to better understand the complex skin thermoregulation behaviour, and therefore, to use IRT in a more objective, accurate and professional way to improve the new IRT applications for the physical activity and sport sector.
Resumo:
The optoelectronic properties of Cu2ZnSnS4 and environmental considerations have attracted significant interest for photovoltaics. Using first-principles, we analyze the possible improvement of this material as a photovoltaic absorber via the isoelectronic substitution of S with O atoms. The evolution of the acceptor level is analyzed with respect to the atomic position of the nearest neighbors of the O atom. We estimate the maximum efficiency of this compound when used as a light absorber. The presence of the sub-band gap level below the conduction band could increases the solar-energy conversion with respect to the host.
Resumo:
The wake produced by the structural supports of the ultrasonic anemometers (UAs)causes distortions in the velocity field in the vicinity of the sonic path. These distortions are measured by the UA, inducing errors in the determination of the mean velocity, turbulence intensity, spectrum, etc.; basic parameters to determine the effect of wind on structures. Additionally, these distortions can lead to indefinition in the calibration function of the sensors (Cuerva et al., 2004). Several wind tunnel tests have been dedicated to obtaining experimental data, from which have been developed fit models to describe and to correct these distortions (Kaimal, 1978 and Wyngaard, 1985). This work explores the effect of a vortex wake generated by the supports of an UA, on the measurement of wind speed done by this instrument. To do this, the Von Karman¿s vortex street potential model is combined with the mathematical model of the measuring process carried out by UAs developed by Franchini et al. (2007). The obtained results are the correction functions of the measured wind velocity, which depends on the geometry of the sonic anemometer and aerodynamic conditions. These results have been validated with the ones obtained in a wind tunnel test done on a single path UA, especially developed for research. The supports of this UA have been modified in order to reproduce the conditions of the theoretical model. Good agreements between experimental and theoretical results have been found.
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All activities of an organization involve risks that should be managed. The risk management process aids decision making by taking account of uncertainty and the possibility of future events or circumstances (intended or unintended) and their effects on agreed objectives. With that idea, new ISO Standard has been drawn up. ISO 31010 has been recently issued which provides a structured process that identifies how objectives may be affected, and analyses the risk in term of consequences and their probabilities before deciding on whether further treatment is required. In this lecture, that ISO Standard has been adapted to Open Pit Blasting Operations, focusing in Environmental effects which can be managed properly. Technique used is Fault Tree Analysis (FTA), which is applied in all possible scenarios, providing to Blasting Professionals the tools to identify, analyze and manage environmental effects in blasting operations. Also this lecture can help to minimize each effect, studying each case. This paper also can be useful to Project Managers and Occupational Health and Safety Departments (OH&S) because blasting operations can be evaluated and compared one to each other to determine the risks that should be managed in different case studies. The environmental effects studied are: ground vibrations, flyrock and air overpressure (airblast). Sometimes, blasting operations are carried out near populated areas where environmental effects may impose several limitations on the use of explosives. In those cases, where these factors approach certain limits, National Standards and Regulations have to be applied.
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This paper presents a mechanical actuator for the biomimetic propulsion of swimming devices and the experimental study of the effect of the caudal fin elasticity on the overall performance. The design of the proposed drive allows the DC motor to operate at constant speed, so all the power of the motor is spent only for the motion of the caudal fin. A prototype of the actuator, in which the caudal fin serves as a driving element, is manufactured and tested in both laboratory and natural conditions. The swimming speed, the thrust efficiency and the maneuverability are evaluated for caudal fins with different stiffness. The caudal fin whose rigidity varies relative to both vertical and horizontal cross-section, exhibits the best performance. The achieved results also confirm that the proposed actuator could be of great interest to applications in the field of underwater operation, ocean investigation and environmental protection.
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Soil erosion is a serious environmental threat in the Mediterranean region due to torrential rainfalls, and it contributes to the degradation of agricultural land. Techniques such as rainwater harvesting may improve soil water storage and increase agricultural productivity, which could result in more effective land usage. Reservoir tillage is an effective system of harvesting rainwater, but it has not been scientifically evaluated like other tillage systems. Its suitability for the conditions in Spain has not been determined. To investigate and quantify water storage from reservoir tillage and how it could be adapted to improve infiltration of harvested rainwater, a laboratory-scale rainfall simulator was developed. Rainfall characteristics, including rainfall intensity, spatial uniformity and raindrop size, confirm that natural rainfall conditions are simulated with sufficient accuracy. The simulator was auto-controlled by a solenoid valve and three pressure nozzles were used to spray water corresponding to five rainfall intensities ranging from 36 to 112 mm h-1 for 3 to 101-year return period with uniformity coefficients between 83 and 94%. In order to assess the reservoir tillage method under surface slopes of 0, 5, and 10%, three soil scooping devices with identical volume were used to make depressions in the following forms: a) truncated square pyramid, b) triangular prism, and c) truncated cone. These depressions were compared to a control soil surface with no depression. For the loam soil used in this study, results show that reservoir tillage was able to reduce soil erosion and surface runoff and significantly increase infiltration. There was significant difference between the depressions and the control. Compared to the control, depression (a) reduced surface runoff by about 61% and the sediment yield concentration by about 79%.
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The effect of water potential ( J w ) on the growth of 15 fungal species isolated from cheeses was analysed. The species, identified mainly by analysis of DNA sequences, belonged to genera Penicillium , Geotrichum , Mucor , Aspergillus , Microascus and Talaromyces . Particularly, the effect of matric potential ( J m ), and ionic (NaCl) and non-ionic (glycerol) solute potentials ( J s ) on growth rate was studied. The response of strains was highly dependent on the type of J w . For J s , clear profiles for optimal, permissive and marginal conditions for growth were obtained, and differences in growth rate were achieved comparing NaCl and glycerol for most of the species. Conversely, a sustained growth was obtained for J m in all the strains, with the exception of Aspergillus pseudoglaucus , whose growth increased proportionally to the level of water stress. Our results might help to understand the impact of environmental factors on the ecophysiology and dynamics of fungal populations associated to cheeses.