26 resultados para Low-impact camping


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This paper describes the potential impact of social media and new technologies in secondary education. The case of study has been designed for the drama and theatre subject. A wide set of tools like social networks, blogs, internet, multimedia content, local press and other promotional tools are promoted to increase students’ motivation. The experiment was developed at the highschool IES Al-Satt located in Algete in the Comunidad de Madrid. The students included in the theatre group present a low academic level, 80% of them had previously repeated at least one grade, half of them come from programs for students with learning difficulties and were at risk of social exclusion. This action is supported by higher and secondary education professors and teachers who look forward to implanting networked media technologies as new tools to improve the academic results and the degree of involvement of students. The results of the experiment have been excellent, based on satisfactory opinions obtained from a survey answered by students at the end of the course, and also revealed by the analytics taken from different social networks. This project is a pioneer in the introduction and usage of new technologies in secondary high-schools in Spain.

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Results of previous studies conducted by different researchers have shown that impact techniques can be used to evaluate firmness (Delwiche et al., 1989; Delwiche et al.;1996; Jaren et al., 1992; Ruiz Altisent et al., 1996). To impact the fruit with a small spherical impactor of known mass and radius of curvature and measure the acceleration of the impactor is a technique described by Chen et al. (1985) and used by several researchers for sensing fruit firmness (Jaren et al., 1992; Correa et al.; 1992). The advantages of this method vs. a force sensor that measures the force as a function of time is that the measured impact-acceleration response is independent of the fruit mass and is less sensitive to the variation in the radius of curvature of the fruit (Chen et al., 1996). Ruiz Altisent et al. (1993) developed and used a 50 g impactor with a 19 mm diameter spherical tip, dropping from different height for fruits (apples, pears, avocados, melons, peaches ...). Another impact device for firmness sensing of fruits was developed by Chen and Ruiz Altisent (1996). They designed and fabricated an experimental low-mass impact sensor for high-speed sensing of fruit firmness. The impactor consisted of a semi-spherical impacting tip attached to the end (near the centre of percussion) of a pivoting arm. Impact is done by swinging the impactor to collide with the fruit. It has been implemented for on-line use. In both devices a small accelerometer is mounted behind the impacting tip. Lateral impactor and vertical impactor have been used in laboratory and the results from non-destructive impact tests have contributed to standardise methods to measure fruit firmness: Barreiro (1992) compared impact parameters and results of Magness-Taylor penetration tests for apples, pears, apricots [and peaches; Agulheiro (1994) studied the behaviour of the impact parameters during seven weeks of cold storage of two melon varieties; Ortiz (1998) used low energy impact and NIR procedures to segregate non crispy, non firm and soft peaches. Steinmetz (1996) compared various non-destructive firmness sensors, based on sound, impact and micro-deformation.

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We examined the consequences of the spatial heterogeneity of atmospheric ammonia (NH3) by measuring and modelling NH3 concentrations and deposition at 25 m grid resolution for a rural landscape containing intensive poultry farming, agricultural grassland, woodland and moorland. The emission pattern gave rise to a high spatial variability of modelled mean annual NH3 concentrations and dry deposition. Largest impacts were predicted for woodland patches located within the agricultural area, while larger moorland areas were at low risk, due to atmospheric dispersion, prevailing wind direction and low NH3 background. These high resolution spatial details are lost in national scale estimates at 1 km resolution due to less detailed emission input maps. The results demonstrate how the spatial arrangement of sources and sinks is critical to defining the NH3 risk to semi-natural ecosystems. These spatial relationships provide the foundation for local spatial planning approaches to reduce environmental impacts of atmospheric NH3.

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On December 17 came into force on community standard marine fuels. Bunker prices are expected to increase, recent statistics support this argument and the difference between the high sulphur (HS) and the low sulphur (LS) marine bunkers will be sustained. Considering also the price difference between the basis-market of Rotterdam with the rest European ports, the expected bunker prices will be higher in the Mediterranean. This paper begins with a review of the current situation in ECAS areas, highlighting the rules to be implemented shortly. The aim of the paper is known the current situation bunkering determine the estimated short term in Spain from world fleet.

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The current space environment, consisting of manmade debris and micrometeoroids, poses a risk to safe operations in space, and the situation is continuously deteriorating due to in-orbit debris collisions and to new satellite launches. Bare electrodynamic tethers can provide an efficient mechanism for rapid deorbiting of satellites from low Earth orbit at end of life. Because of its particular geometry (length very much larger than cross-sectional dimensions), a tether may have a relatively high risk of being severed by the single impact of small debris. The rates of fatal impact of orbital debris on round and tape tethers of equal length and mass, evaluated with an analytical approximation to debris flux modeled by NASA’s ORDEM2000, shows much higher survival probability for tapes. A comparative numerical analysis using debris flux model ORDEM2000 and ESA’s MASTER2005 validates the analytical result and shows that, for a given time in orbit, a tape has a probability of survival of about one and a half orders of magnitude higher than a round tether of equal mass and length. Because deorbiting from a given altitude is much faster for the tape due to its larger perimeter, its probability of survival in a practical sense is quite high.

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We show that for a tether at 800 km altitude, which is 5 km long, 2 cm wide and 0.05 mm thick, the risk of substantial damage during a 3 month period due to multiple impacts with debris or micrometeoroids is low, of about 1.4%. By substantial damage we mean that if the tape is divided in 2 cm2 cm squares, then in some square the damaged area by bombardment with debris or micrometeoroids exceeds 11% of the area of the square. Furthermore, we show that the danger posed by the micrometeoroids is negligible compared to the risk posed by the debris.

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Un caloducto en bucle cerrado o Loop Heat Pipe (LHP) es un dispositivo de transferencia de calor cuyo principio de operación se basa en la evaporación/condensación de un fluido de trabajo, que es bombeado a través de un circuito cerrado gracias a fuerzas de capilaridad. Gracias a su flexibilidad, su baja masa y su mínimo (incluso nulo) consumo de potencia, su principal aplicación ha sido identificada como parte del subsistema de control térmico de vehículos espaciales. En el presente trabajo se ha desarrollado un LHP capaz de funcionar eficientemente a temperaturas de hasta 125 oC, siguiendo la actual tendencia de los equipos a bordo de satélites de incrementar su temperatura de operación. En la selección del diseño optimo para dicho LHP, la compatibilidad entre materiales y fluido de trabajo se identificó como uno de los puntos clave. Para seleccionar la mejor combinación, se llevó a cabo una exhaustiva revisión del estado del arte, además de un estudio especifico que incluía el desarrollo de un banco de ensayos de compatibilidad. Como conclusión, la combinación seleccionada como la candidata idónea para ser integrada en el LHP capaz de operar hasta 125 oC fue un evaporador de acero inoxidable, líneas de titanio y amoniaco como fluido de trabajo. En esa línea se diseñó y fabricó un prototipo para ensayos y se desarrolló un modelo de simulación con EcosimPro para evaluar sus prestaciones. Se concluyó que el diseño era adecuado para el rango de operación definido. La incompatibilidad entre el fluido de trabajo y los materiales del LHP está ligada a la generación de gases no condensables. Para un estudio más detallado de los efectos de dichos gases en el funcionamiento del LHP se analizó su comportamiento con diferentes cantidades de nitrógeno inyectadas en su cámara de compensación, simulando un gas no condensable formado en el interior del dispositivo. El estudio se basó en el análisis de las temperaturas medidas experimentalmente a distintos niveles de potencia y temperatura de sumidero o fuente fría. Adicionalmente, dichos resultados se compararon con las predicciones obtenidas por medio del modelo en EcosimPro. Las principales conclusiones obtenidas fueron dos. La primera indica que una cantidad de gas no condensable más de dos veces mayor que la cantidad generada al final de la vida de un satélite típico de telecomunicaciones (15 años) tiene efectos casi despreciables en el funcionamiento del LHP. La segunda es que el principal efecto del gas no condensable es una disminución de la conductancia térmica, especialmente a bajas potencias y temperaturas de sumidero. El efecto es más significativo cuanto mayor es la cantidad de gas añadida. Asimismo, durante la campaña de ensayos se observó un fenómeno no esperado para grandes cantidades de gas no condensable. Dicho fenómeno consiste en un comportamiento oscilatorio, detectado tanto en los ensayos como en la simulación. Este efecto es susceptible de una investigación más profunda y los resultados obtenidos pueden constituir la base para dicha tarea. ABSTRACT Loop Heat Pipes (LHPs) are heat transfer devices whose operating principle is based on the evaporation/condensation of a working fluid, and which use capillary pumping forces to ensure the fluid circulation. Thanks to their flexibility, low mass and minimum (even null) power consumption, their main application has been identified as part of the thermal control subsystem in spacecraft. In the present work, an LHP able to operate efficiently up to 125 oC has been developed, which is in line with the current tendency of satellite on-board equipment to increase their operating temperatures. In selecting the optimal LHP design for the elevated temperature application, the compatibility between the materials and working fluid has been identified as one of the main drivers. An extensive literature review and a dedicated trade-off were performed, in order to select the optimal combination of fluids and materials for the LHP. The trade-off included the development of a dedicated compatibility test stand. In conclusion, the combination of stainless steel evaporator, titanium piping and ammonia as working fluid was selected as the best candidate to operate up to 125 oC. An LHP prototype was designed and manufactured and a simulation model in EcosimPro was developed to evaluate its performance. The first conclusion was that the defined LHP was suitable for the defined operational range. Incompatibility between the working fluid and LHP materials is linked to Non Condensable Gas (NCG) generation. Therefore, the behaviour of the LHP developed with different amounts of nitrogen injected in its compensation chamber to simulate NCG generation, was analyzed. The LHP performance was studied by analysis of the test results at different temperatures and power levels. The test results were also compared to simulations in EcosimPro. Two additional conclusions can be drawn: (i) the effects of an amount of more than two times the expected NCG at the end of life of a typical telecommunications satellite (15 years) is almost negligible on the LHP operation, and (ii) the main effect of the NCG is a decrease in the LHP thermal conductance, especially at low temperatures and low power levels. This decrease is more significant with the progressive addition of NCG. An unexpected phenomenon was observed in the LHP operation with large NCG amounts. Namely, an oscillatory behaviour, which was observed both in the tests and the simulation. This effect provides the basis for further studies concerning oscillations in LHPs.

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The effects of nature on people's mind have been an active research theme for decades. However, the impact of people's mind on landscape ecological health has received less attention. How and why perception, meanings and mental constructs determine the way nature is valued and consequently managed? How this interplay should be? These are in some cases more relevant questions than knowing what particular landscapes are preferred (Carlson 1993). This was the underlying inquiry in the focus group experience held in a natural protected area in La Rioja (Spain). Participants were asked to locate in a map areas representing low/high quality in terms of ecology and aesthetics. Some relevant conclusions for landscape management were derived from the analysis of participant's discourse in terms of ecological aesthetical appreciation and their consideration about how human takes place in nature.

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Smart and green cities are hot topics in current research because people are becoming more conscious about their impact on the environment and the sustainability of their cities as the population increases. Many researchers are searching for mechanisms that can reduce power consumption and pollution in the city environment. This paper addresses the issue of public lighting and how it can be improved in order to achieve a more energy efficient city. This work is focused on making the process of turning the streetlights on and off more intelligent so that they consume less power and cause less light pollution. The proposed solution is comprised of a radar device and an expert system implemented on a low-cost platform based on a DSP. By analyzing the radar echo in both the frequency and time domains, the system is able to detect and identify objects moving in front of it. This information is used to decide whether or not the streetlight should be turned on. Experimental results show that the proposed system can provide hit rates over 80%, promising a good performance. In addition, the proposed solution could be useful in kind of other applications such as intelligent security and surveillance systems and home automation.

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One of the main objectives of European Commission related to climate and energy is the well-known 20-20-20 targets to be achieved in 2020: Europe has to reduce greenhouse gas emissions of at least 20% below 1990 levels, 20% of EU energy consumption has to come from renewable resources and, finally, a 20% reduction in primary energy use compared with projected levels, has to be achieved by improving energy efficiency. In order to reach these objectives, it is necessary to reduce the overall emissions, mainly in transport (reducing CO2, NOx and other pollutants), and to increase the penetration of the intermittent renewable energy. A high deployment of battery electric (BEVs) and plug-in hybrid electric vehicles (PHEVs), with a low-cost source of energy storage, could help to achieve both targets. Hybrid electric vehicles (HEVs) use a combination of a conventional internal combustion engine (ICE) with one (or more) electric motor. There are different grades of hybridation from micro-hybrids with start-stop capability, mild hybrids (with kinetic energy recovery), medium hybrids (mild hybrids plus energy assist) and full hybrids (medium hybrids plus electric launch capability). These last types of vehicles use a typical battery capacity around 1-2 kWh. Plug in hybrid electric vehicles (PHEVs) use larger battery capacities to achieve limited electric-only driving range. These vehicles are charged by on-board electricity generation or either plugging into electric outlets. Typical battery capacity is around 10 kWh. Battery Electric Vehicles (BEVs) are only driven by electric power and their typical battery capacity is around 15-20 kWh. One type of PHEV, the Extended Range Electric Vehicle (EREV), operates as a BEV until its plug-in battery capacity is depleted; at which point its gasoline engine powers an electric generator to extend the vehicle's range. The charging of PHEVs (including EREVs) and BEVs will have different impacts to the electric grid, depending on the number of vehicles and the start time for charging. Initially, the lecture will start analyzing the electrical power requirements for charging PHEVs-BEVs in Flanders region (Belgium) under different charging scenarios. Secondly and based on an activity-based microsimulation mobility model, an efficient method to reduce this impact will be presented.

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El sector energético, en España en particular, y de forma similar en los principales países de Europa, cuenta con una significativa sobrecapacidad de generación, debido al rápido y significativo crecimiento de las energías renovables en los últimos diez años y la reducción de la demanda energética, como consecuencia de la crisis económica. Esta situación ha hecho que las centrales térmicas de generación de electricidad, y en concreto los ciclos combinados de gas, operen con un factor de utilización extremadamente bajo, del orden del 10%. Además de la reducción de ingresos, esto supone para las plantas trabajar continuamente fuera del punto de diseño, provocando una significativa pérdida de rendimiento y mayores costes de explotación. En este escenario, cualquier contribución que ayude a mejorar la eficiencia y la condición de los equipos, es positivamente considerada. La gestión de activos está ganando relevancia como un proceso multidisciplinar e integrado, tal y como refleja la reciente publicación de las normas ISO 55000:2014. Como proceso global e integrado, la gestión de activos requiere el manejo de diversos procesos y grandes volúmenes de información, incluso en tiempo real. Para ello es necesario utilizar tecnologías de la información y aplicaciones de software. Esta tesis desarrolla un concepto integrado de gestión de activos (Integrated Plant Management – IPM) aplicado a centrales de ciclo combinado y una metodología para estimar el beneficio aportado por el mismo. Debido a las incertidumbres asociadas a la estimación del beneficio, se ha optado por un análisis probabilístico coste-beneficio. Así mismo, el análisis cuantitativo se ha completado con una validación cualitativa del beneficio aportado por las tecnologías incorporadas al concepto de gestión integrada de activos, mediante una entrevista realizada a expertos del sector de generación de energía. Los resultados del análisis coste-beneficio son positivos, incluso en el desfavorable escenario con un factor de utilización de sólo el 10% y muy prometedores para factores de utilización por encima del 30%. ABSTRACT The energy sector particularly in Spain, and in a similar way in Europe, has a significant overcapacity due to the big growth of the renewable energies in the last ten years, and it is seriously affected by the demand decrease due to the economic crisis. That situation has forced the thermal plants and in particular, the combined cycles to operate with extremely low annual average capacity factors, very close to 10%. Apart from the incomes reduction, working in out-of-design conditions, means getting a worse performance and higher costs than expected. In this scenario, anything that can be done to improve the efficiency and the equipment condition is positively received. Asset Management, as a multidisciplinary and integrated process, is gaining prominence, reflected in the recent publication of the ISO 55000 series in 2014. Dealing Asset Management as a global, integrated process needs to manage several processes and significant volumes of information, also in real time, that requires information technologies and software applications to support it. This thesis proposes an integrated asset management concept (Integrated Plant Management-IPM) applied to combined cycle power plants and develops a methodology to assess the benefit that it can provide. Due to the difficulties in getting deterministic benefit estimation, a statistical approach has been adopted for the cot-benefit analysis. As well, the quantitative analysis has been completed with a qualitative validation of the technologies included in the IPM and their contribution to key power plant challenges by power generation sector experts. The cost- benefit analysis provides positive results even in the negative scenario of annual average capacity factor close to 10% and is promising for capacity factors over 30%.