1,721,104 research outputs found
Mechanisms for CubeSats and SmallSats
No full textCubeSat mechanisms usually represent dedicated technical solutions and are often developed as mission-specific or product-specific developments. By contrast, other CubeSat systems are often available as off-the-shelf components. This difference reduces the availability and the possibility to integrate standard mechanisms across custom platforms. Despite this limitation, the increasing capabilities and ambitious goals of CubeSat missions are making mechanisms fundamental parts of current and future projects. In this chapter the state of the art and the future advancements of mechanisms for CubeSat are presented. First, the main design drivers for CubeSat mechanisms development are introduced; the most common mechanism applications and some potential future developments are then classified in function of three application fields: antennas deployment, solar array mechanisms, and other mechanisms
An attempt at modelling the lithosphere of Sardinia block and surroundings: relationships among isostatic disequilibrium, geomorphic features and neotectonics
No full textMechanical influence of inherited folds in thrust development: A case study from the variscan fold-and-thrust belt in SW sardinia (Italy)
Full text linkFold-and-thrust belts have a high variability of structural styles, whose investigation provides continuous updates of the predictive models that try to better approximate the geometries recognized in the field. The majority of studies are focused on the geometry and development of folds and thrust surfaces and the amount of displacement, taking into account the role played by the involved stratigraphic succession assumed as a layer cake. We present a case study from the external zone of the Variscan fold-and-thrust belt in SW Sardinia, where it was possible to investigate the lateral and vertical variations of the mechanical properties of the involved succession, how they related to previous folding, control thrust geometry, and kinematics. In this case, the superposition of two fold systems acted as a buttress that induced extensive back-thrusting. We found that there is a close connection between the attitude of the bedding and the geometry of back thrust surfaces, shear strength during thrust propagation, and variation in the shortening amount, de-pending on which part of the folds were cut across. The folding-related mechanical anisotropy also seems to have induced a ductile deformation in the footwall of back-thrusts. Although the case study considers the development of back-thrust, the relations between thrust and not-layer cake geometries could also be applied to fore-thrust development
Regole per l'istruttorialegislativa e la redazione tecnica, Relazione al Seminario nazionale di Studi sugli strumenti per il drafting e il linguaggio delle leggi, Bologna, 19-20 giuno 1997
No full text
Gravity field and geothermal structure of the Corsica-Sardinia Block
No full textThis paper presents a finite-differences 3D numerical model that simulates the gravity and thermal structure of the Corsica-Sardinia Block (CSB), an apparently stable lithospheric domain characterized by cryptic tectonic activity. In the experiments, we change the density and heat production rate of the model crust within a range of geologically realistic values to fit the measured Bouguer gravity anomaly and surface heat flow pattern. The discrepancy between the observed geophysical structure and the outcomes of numerical modelling are discussed in relation to the composition of the CSB crust and finally recast in the geodynamic framework of the western Mediterranean region
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Scenario Optimization Asset and Liability Modelling for Individual Investors
Full text linkWe develop a scenario optimization model for asset and liability management of
individual investors. The individual has a given level of initial wealth and a target goal to be
reached within some time horizon. The individual must determine an asset allocation strategy
so that the portfolio growth rate will be sufficient to reach the target. A scenario optimization
model is formulated which maximizes the upside potential of the portfolio, with limits on
the downside risk. Both upside and downside are measured vis- `a-vis the goal. The stochastic
behavior of asset returns is captured through bootstrap simulation, and the simulation is
embedded in the model to determine the optimal portfolio. Post-optimality analysis using
out-of-sample scenarios measures the probability of success of a given portfolio. It also
allows us to estimate the required increase in the initial endowment so that the probability of
success is improved
- …
