8 resultados para container planting
em Universidad Politécnica de Madrid
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This paper is concerned with the study of non-Markovian queuing systems in container terminals. The methodology presented has been applied to analyze the ship traffic in the port of Valencia located in the Western Mediterranean. Two container terminals have been studied: the public container terminal of NOATUM and the dedicated container terminal of MSC. This paper contains the results of a simulation model based on queuing theory. The methodology presented is found to be effective in replicating realistic ship traffic operations in port as well as in conducting capacity evaluations. Thus the methodology can be used for capacity planning (long term), tactical planning (medium term) and even for the container terminal design (port enlargement purposes).
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This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control. Based on the concept of service segmentation, the authors employed control charts to classify container terminal services. The purpose of control charts is to allow simple detection of events that are indicative of actual process change. This simple decision can be difficult where the process characteristic is continuously varying, the control chart provides statistically objective criteria of change. When change is detected and considered good its cause should be identified and possibly become the new way of working, where the change is bad then its cause should be identified and eliminated. Both theoretical and practical implications of the research findings are discussed in this paper.
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This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control. Based on the concept of service segmentation, we employed control charts to classify container terminal services. The purpose of control charts is to allow simple detection of events that are indicative of actual process change. This simple decision can be difficult where the process characteristic is continuously varying; the control chart provides statistically objective criteria of change. When change is detected and considered good its cause should be identified and possibly become the new way of working, where the change is bad then its cause should be identified and eliminated. This paper is organized as follows: Section 1 is the introduction, Section 2 provides a brief note on other studies that inspired this research, section 3 focuses on the methodology used, and develops the results obtained and finally conclusions are shown in Section 4. Theoretical and practical implications of the research findings are discussed.
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Conferencia Internacional Nutrient Dynamics of Planted Forests, Noviembre de 2012
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The neutron Howitzer container at the Neutron Measurements Laboratory of the Nuclear Engineering Department of the Polytechnic University of Madrid (UPM), is equipped with a 241Am-Be neutron source of 74 GBq in its center. The container allows the source to be in either the irradiation or the storage position. To measure the neutron fluence rate spectra around the Howitzer container, measurements were performed using a Bonner spheres spectrometer and the spectra were unfolded using the NSDann program. A calibrated neutron area monitor LB6411 was used to measure the ambient dose equivalent rates, H*(10). Detailed Monte-Carlo simulations were performed to calculate the measured quantities at the same positions. The maximum relative deviation between simulations and measurements was 19.53%. After validation, the simulated model was used to calculate the equivalent dose rate in several key organs of a voxel phantom. The computed doses in the skin and lenses of the eyes are within the ICRP recommended dose limits, as is the H*(10) value for the storage position.
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Article New Forests November 2015, Volume 46, Issue 5, pp 869-883 First online: 17 June 2015 Establishing Quercus ilex under Mediterranean dry conditions: sowing recalcitrant acorns versus planting seedlings at different depths and tube shelter light transmissionsJuan A. OlietAffiliated withDepartamento de Sistemas y Recursos Naturales, E.T.S. Ingenieros de Montes, Universidad Politécnica de Madrid Email author View author's OrcID profile , Alberto Vázquez de CastroAffiliated withDepartamento de Sistemas y Recursos Naturales, E.T.S. Ingenieros de Montes, Universidad Politécnica de Madrid, Jaime PuértolasAffiliated withLancaster Environment Centre, Lancaster University $39.95 / €34.95 / £29.95 * Rent the article at a discount Rent now * Final gross prices may vary according to local VAT. Get Access AbstractSuccess of Mediterranean dry areas restoration with oaks is a challenging goal. Testing eco-techniques that mimic beneficial effects of natural structures and ameliorate stress contributes to positive solutions to overcoming establishment barriers. We ran a factorial experiment in a dry area, testing two levels of solid wall transmission of tube shelters (60 and 80 %) plus a control mesh, and two depths (shallow and 15 cm depth) of placing either planted seedlings or acorns of Quercus ilex. Microclimate of the planting or sowing spots was characterized by measuring photosynthetically active radiation, temperature and relative humidity. Plant response was evaluated in terms of survival, phenology, acorn emergence and photochemical efficiency (measured through chlorophyll fluorescence). We hypothesize that tube shelters and deep planting improve Q. ilex post-planting and sowing performance because of the combined effects of reducing excessive radiation and improving access to moist soil horizons. Results show that temperature and PAR was reduced, and relative humidity increased, in deep spots. Midsummer photochemical efficiency indicates highest level of stress for oaks in 80 % light transmission shelter. Optimum acorn emergence in spring was registered within solid wall tree shelters, and maximum summer survival of germinants and of planted seedlings occurred when acorns or seedlings were placed at 15 cm depth irrespectively of light transmission of shelter. Survival of germinants was similar to that of planted seedlings. The importance of techniques to keep high levels of viability after sowing recalcitrant seeds in the field is emphasized in the study
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Las terminales de contenedores son sistemas complejos en los que un elevado número de actores económicos interactúan para ofrecer servicios de alta calidad bajo una estricta planificación y objetivos económicos. Las conocidas como "terminales de nueva generación" están diseñadas para prestar servicio a los mega-buques, que requieren tasas de productividad que alcanzan los 300 movimientos/ hora. Estas terminales han de satisfacer altos estándares dado que la competitividad entre terminales es elevada. Asegurar la fiabilidad de las planificaciones del atraque es clave para atraer clientes, así como reducir al mínimo el tiempo que el buque permanece en el puerto. La planificación de las operaciones es más compleja que antaño, y las tolerancias para posibles errores, menores. En este contexto, las interrupciones operativas deben reducirse al mínimo. Las principales causas de dichas perturbaciones operacionales, y por lo tanto de incertidumbre, se identifican y caracterizan en esta investigación. Existen una serie de factores que al interactuar con la infraestructura y/o las operaciones desencadenan modos de fallo o parada operativa. Los primeros pueden derivar no solo en retrasos en el servicio sino que además puede tener efectos colaterales sobre la reputación de la terminal, o incluso gasto de tiempo de gestión, todo lo cual supone un impacto para la terminal. En el futuro inmediato, la monitorización de las variables operativas presenta gran potencial de cara a mejorar cualitativamente la gestión de las operaciones y los modelos de planificación de las terminales, cuyo nivel de automatización va en aumento. La combinación del criterio experto con instrumentos que proporcionen datos a corto y largo plazo es fundamental para el desarrollo de herramientas que ayuden en la toma de decisiones, ya que de este modo estarán adaptadas a las auténticas condiciones climáticas y operativas que existen en cada emplazamiento. Para el corto plazo se propone una metodología con la que obtener predicciones de parámetros operativos en terminales de contenedores. Adicionalmente se ha desarrollado un caso de estudio en el que se aplica el modelo propuesto para obtener predicciones de la productividad del buque. Este trabajo se ha basado íntegramente en datos proporcionados por una terminal semi-automatizada española. Por otro lado, se analiza cómo gestionar, evaluar y mitigar el efecto de las interrupciones operativas a largo plazo a través de la evaluación del riesgo, una forma interesante de evaluar el effecto que eventos inciertos pero probables pueden generar sobre la productividad a largo plazo de la terminal. Además se propone una definición de riesgo operativo junto con una discusión de los términos que representan con mayor fidelidad la naturaleza de las actividades y finalmente, se proporcionan directrices para gestionar los resultados obtenidos. Container terminals are complex systems where a large number of factors and stakeholders interact to provide high-quality services under rigid planning schedules and economic objectives. The socalled next generation terminals are conceived to serve the new mega-vessels, which are demanding productivity rates up to 300 moves/hour. These terminals need to satisfy high standards because competition among terminals is fierce. Ensuring reliability in berth scheduling is key to attract clients, as well as to reduce at a minimum the time that vessels stay the port. Because of the aforementioned, operations planning is becoming more complex, and the tolerances for errors are smaller. In this context, operational disturbances must be reduced at a minimum. The main sources of operational disruptions and thus, of uncertainty, are identified and characterized in this study. External drivers interact with the infrastructure and/or the activities resulting in failure or stoppage modes. The later may derive not only in operational delays but in collateral and reputation damage or loss of time (especially management times), all what implies an impact for the terminal. In the near future, the monitoring of operational variables has great potential to make a qualitative improvement in the operations management and planning models of terminals that use increasing levels of automation. The combination of expert criteria with instruments that provide short- and long-run data is fundamental for the development of tools to guide decision-making, since they will be adapted to the real climatic and operational conditions that exist on site. For the short-term a method to obtain operational parameter forecasts in container terminals. To this end, a case study is presented, in which forecasts of vessel performance are obtained. This research has been entirely been based on data gathered from a semi-automated container terminal from Spain. In the other hand it is analyzed how to manage, evaluate and mitigate disruptions in the long-term by means of the risk assessment, an interesting approach to evaluate the effect of uncertain but likely events on the long-term throughput of the terminal. In addition, a definition for operational risk evaluation in port facilities is proposed along with a discussion of the terms that better represent the nature of the activities involved and finally, guidelines to manage the results obtained are provided.
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The study of the temperature gradients in cold stores and containers is a critical issue in the food industry for the quality assurance of products during transport and for minimising losses. This work presents an analysis of the temperatures during the refrigerated transport of 4,320 kg of blueberries in a reefer (set point temperature at ?1ºC) on a container ship from Montevideo (Uruguay) to Verona (Italy). The monitoring was performed by using semi-passive RFID loggers (TurboTag cards). The objective was to carry out a multi-distributed supervision using low-cost, wireless and autonomous sensors for the characterisation of the distribution and spatial gradients of temperatures during a long distance transport. Data analysis shows spatial (phase space) and temporal sequencing diagrams and reveals a significant heterogeneity of temperature at different locations in the container, which highlights the ineffectiveness of a temperature control system based on a single sensor, as is usually done.