Assessment of the structural properties of timber members in situ : a probabilistic approach

The assessment of the structural performance of existing timber structures is dependent, among other factors, on the capacity to evaluate the physical and mechanical properties of structural timber elements in situ. This paper discusses the possibilities/advantages of using a probabilistic approach to obtain a more reliable prediction of the reference properties of these timber members in situ. The presented approach combines information from common non-destructive techniques (NDT), such as visual assessment and ultrasounds, and those from semi-destructive tests (SDT), as meso tension specimens and wood cores. An application of this approach to maritime pine (Pinus pinaster Ait.) and chestnut (Castanea sativa Mill.) timber pieces of structural dimension is presented

Carbon balance estimation for agroforestry land use alternatives in Portugal

PosterIn 2005, 11% of the anthropogenic greenhouse gases emissions (GHG) were originated from agricultural activities and this value is expected to increase in the future. Besides the contribution for the restoration of soil productivity and for the improvement of conditions in degraded land, Agroforestry is also proposed as one of the main solutions for the mitigation of the GHG emissions and their effect on Climate Change. With European Union’s legislation supporting and promoting the conversion of land into low-carbon-integrated agriculture, new opportunities arise for the implementation of this type of land use in Europe. In Portugal, this type of agriculture is well represented by a traditional Agroforestry system called montado, combining low density cork oak trees (Quercus suber L) with pastoral activities occupying an area of 715,922 ha, with recent studies showing an extra area suitable for its implementation of around 353,000ha. Considering the new policies established by the EU in regard to the measures to be considered in agriculture for the Climate Change mitigation, and the capacity of the Agroforestry systems to act as a low-carbon and highly productive agriculture, two main objectives are proposed for this work: 1) Compare the potential capacity of the montado to mitigate the GHG emissions by quantifying the net carbon balance of activities in comparison to two other land-use alternatives occurring in the same area: dense cork oak forestry and wheat monoculture; 2) Quantify the benefits/consequences in terms of net carbon balance if new areas are converted into Agroforestry systems, as an alternative to current activities and management models. The methodology for the net carbon balance estimation includes the use of the Yield-SAFE model, calibrated for crop components and cork oak and current most used management practices concerning the three land use types and associated activities.AGFORWARD FP7 (contract nº 613520); FCT CorkCarbon Footprint (PTDC/AGR-FOR/4360/2012

Using the yield-safe model to assess hypothetical eucalyptus silvopastoral systems in Portugal

info:eu-repo/semantics/publishedVersio

Modelling holm oak acorn production in south western Iberia

info:eu-repo/semantics/publishedVersio

Innovating tree plantation design: spiralographing agroforestry

PosterMost of forestry or agroforestry artificial plantations either have an orthogonal design, or curvilinear under contour lines to prevent soil erosion. These designs are known to maximize machinery workflow or erosion control respectively. As in many occasions in land use management, what optimizes machinery operation is not what optimizes prevention of soil loss and vice versa. An alternative and intermediate design system such as an Archimedes spiral could offer in one hand, the ability to have equidistant lines to facilitate machinery operation and, in other hand reduce soil loss in comparison to orthogonal designs. Additionally can be an alternative design when aesthetics plays a role in the planting decision. Although the spiral land use design is present in permaculture related literature, scaling up the methodology to forestry is practically absent in literature. This work tries to contribute to the knowledge of planting trees in an Archimedes spiral design. Making a spiral is a trivial command in computer assisted design, but this work envisaged the creation of the spiral in the field without any high technology software (e.g. tractor with laser technology) to enlarge the scope of possible application. We used the spiral equation to explore and define in the spiral: 1) the number of turns, 2) the distance between the arms and 3) the tree density. The widest machinery of the farmer was five meters so, to allow the tractor to move inwards and outwards in the spiral, we opted to design twelve meters between rows to allow 1 meter safety distance to the tree line. The final spiral would have three arms with two meters between trees in the line (240 trees). Part of the challenge was to implement the spiral with the exact dimensions in order to respect the farmer needs. To implement the spiral in the field a “field spiralographer” was made with the following description: an axis with about 1 meter high, where on top was placed a base with six equidistant arms. Each arm was made telescopic to allow different lengths of the arms. At 2 meters from the center the arms were marked and a screw pin was placed on the mark. A rope was rolled up around the screw pins. The number of complete turns is equal to the number of lines existing in the field spiral. Because the union of the screw pins in the arms’ builds a hexagon with 6 x 2 meters perimeter, a full turn has 12 meters length. To mark the spiral in the field, start unrolling the rope and walk at the same time avoiding a loose rope, marking the place for planting the trees. By the end of a full turn around the “spiralographer” there should be 12 meters distance between the first and last tree mark. By keeping unrolling the rope until needed, the spiral keeps being designed in the field depending on the turns needed. In other words, the “spiralographer” could be an hexagon with R radius, being 6xR, the distance between the lines in the spiral. Unrolling and keeping the rope unloose will provide a guide to mark the spiral in the field. Because the description might be unclear, a video was made showing the “making of” this spiral preparation: http://www.youtube.com/watch?v=5lzjT1UcJvM The experimental site is being used to survey operational costs to compare with conventional designs

Using EcoYieldSAFE to compare soil carbon dynamics under future climate in two contrasting agroforestry systems

N/

Recurso. sIMfLOR – plataforma portuguesa de modelos forestales

In the last decades there has been an increasing number of forest models developed for the main species of the Portuguese forest. Forest models support management decisions by predicting long term stand development under alternative scenarios and taking into account all the components of the ecosystem. However, in most cases, there is a gap between the models developed and their application by decision-makers. The platform for Portuguese Forest Simulators (sIMfLOR) tries to overcome this gap integrating a wide variety of forest models into simulators and providing a baseline tool for forest managers in Portugal. As an integrated modular platform, sIMfLOR makes available forest simulators for the Portuguese forest with user-friendly interfaces to facilitate the introduction of the information for the simulators. The platform displays stand and regional simulators, interfaces to generate required inputs and also auxiliary tools. As the platform focus on end-users, it allows visualization of the simulators outputs in default graphics which can easily be edited by users. The sIMfLOR platform can be permanently accessed at http://www.isa.utl.pt/cef/forchange/fctools.En las últimas décadas ha habido un número creciente de modelos forestales desarrollados para las principales especies forestales portuguesas. Los modelos forestales apoyan la toma de decisiones de gestión mediante la predicción del desarrollo a largo plazo de los rodales bajo escenarios alternativos y teniendo en cuenta todos los componentes del ecosistema. Sin embargo, en la mayoría de los casos, existe una brecha entre los modelos desarrollados y su aplicación por los que toman las decisiones. La plataforma portuguesa de simuladores forestales (sIMfLOR) intenta salvar esta brecha integrando una amplia variedad de modelos forestales en simuladores y proporcionando una herramienta de referencia para los gestores forestales en Portugal. Como plataforma modular integrada, sIMfLOR hace accesibles simuladores forestales para los bosques portugueses utilizando interfaces de fácil uso para facilitar la introducción de la información para los simuladores. La plataforma muestra simuladores de rodales y regionales, interfaces para generar insumos necesarios y también herramientas auxiliares. Como el enfoque de la plataforma es en los usuarios finales, permite la visualización de las salidas de los simuladores en gráficos por defecto que pueden ser modificados por los usuarios. A la plataforma sIMfLOR se puede acceder de forma permanente en http://www.isa.utl.pt/cef/forchange/fctools

Evaluation of spatial and temporal variability of pasture based on topography and the quality of the rainy season

Yield and botanical composition of a given dry-land pasture are heavily influenced by rainfall distribution, and vary according to topography. Through analyzing these parameters, it is possible to identify patterns of spatial distribution, related to topographic characteristics, which can be used to improve spatial management of pasture. The main objective of this project was to assess the role of rainfall, temperature and topography in the spatial and temporal variability of pasture and establish models for predicting the spatial distribution and yield of certain plant species, based on its topographic characteristics. This study was carried out over three years, 2004 to 2006, in a dryland pasture located in Southern Portugal. The data obtained were analyzed as a function of distance to flow lines and the results demonstrate that certain topographical characteristics, associated with agronomic information, can be very useful in explaining the spatial and temporal variability of yield and the botanical composition of the pasture. The slope of the linear regression of the variables mentioned can be used to estimate the spatial variation of yield and the botanical composition as a function of distance to flow lines. The regression coefficient can be estimated from the annual rainfall, given the strong correlation between the two

Using continuous measurement to protect a universal set of quantum gates within a perturbed decoherence-free subspace

We consider a universal set of quantum gates encoded within a perturbed decoherence-free subspace of four physical qubits. Using second-order perturbation theory and a measuring device modeled by an infinite set of harmonic oscillators, simply coupled to the system, we show that continuous observation of the coupling agent induces inhibition of the decoherence due to spurious perturbations. We thus advance the idea of protecting or even creating a decoherence-free subspace for processing quantum information.Comment: 7 pages, 1 figure. To be published in Journal of Physics A: Mathematical and Genera

Keeping a parameter-sparse concept in agroforestry modeling while integrating new processes and dynamics: new developments in yield-safe

info:eu-repo/semantics/publishedVersio