Search results for "Modelli"
showing 10 items of 1866 documents
Effect of biobased plasticizers, used as dispersing aids, on mechanical, rheological and thermal properties of micro fibrillated cellulose (MFC)/poly…
2022
Micro Fibrillated Cellulose (MFC) has gained interest both in academia and industry, but some critical issues must be overcome to exploit the industrial MFC/biocomposites uses. In particular, the first drawback is related to the MFC agglomeration during the primary processing. Encouraging results have been obtained using plasticizers, as dispersing aids, during the extrusion that optimizes the process parameters based on the variation of the melt viscosity. However, even if the plasticizer addition counterbalances the excessive biocomposite stiffness, caused by the addition of the MFC, its eventual migration from the finished product needs to be evaluated to avoid toughness reductions as we…
Solving gap metabolites and blocked reactions in genome-scale models: application to the metabolic network of Blattabacterium cuenoti
2013
Abstract Background Metabolic reconstruction is the computational-based process that aims to elucidate the network of metabolites interconnected through reactions catalyzed by activities assigned to one or more genes. Reconstructed models may contain inconsistencies that appear as gap metabolites and blocked reactions. Although automatic methods for solving this problem have been previously developed, there are many situations where manual curation is still needed. Results We introduce a general definition of gap metabolite that allows its detection in a straightforward manner. Moreover, a method for the detection of Unconnected Modules, defined as isolated sets of blocked reactions connect…
On the modelling of an Acid/Base Flow battery: an innovative electrical energy storage device based on pH and salinity gradients
2019
The Acid/Base Flow Battery (AB-FB) is an innovative and sustainable way to store electric energy. It can theoretically guarantee an energy density of about 11 kWh/m3, which is higher than that provided by pumped hydropower, osmotic energy storage and compressed air. The AB-FB stores energy as pH and salinity gradients by employing a stack provided with (i) channels, hosting the solutions at difference pH and concentrations, separated by (ii) monopolar and bipolar ion exchange membranes. Two different membrane processes are involved: the Bipolar Membrane Electrodialysis (ED-BM) as charging step and its opposite, Bipolar Membrane Reverse Electrodialysis (RED-BM) as discharging step. The prese…
A generalized model of elastic foundation based on long-range interactions: Integral and fractional model
2009
The common models of elastic foundations are provided by supposing that they are composed by elastic columns with some interactions between them, such as contact forces that yield a differential equation involving gradients of the displacement field. In this paper, a new model of elastic foundation is proposed introducing into the constitutive equation of the foundation body forces depending on the relative vertical displacements and on a distance-decaying function ruling the amount of interactions. Different choices of the distance-decaying function correspond to different kind of interactions and foundation behavior. The use of an exponential distance-decaying function yields an integro-d…
The mechanically-based approach to 3D non-local linear elasticity theory: Long-range central interactions
2010
Abstract This paper presents the generalization to a three-dimensional (3D) case of a mechanically-based approach to non-local elasticity theory, recently proposed by the authors in a one-dimensional (1D) case. The proposed model assumes that the equilibrium of a volume element is attained by contact forces between adjacent elements and by long-range forces exerted by non-adjacent elements. Specifically, the long-range forces are modelled as central body forces depending on the relative displacement between the centroids of the volume elements, measured along the line connecting the centroids. Further, the long-range forces are assumed to be proportional to a proper, material-dependent, dis…
Mechanically-based approach to non-local elasticity: Variational principles
2010
Abstract The mechanically-based approach to non-local elastic continuum, will be captured through variational calculus, based on the assumptions that non-adjacent elements of the solid may exchange central body forces, monotonically decreasing with their interdistance, depending on the relative displacement, and on the volume products. Such a mechanical model is investigated introducing primarily the dual state variables by means of the virtual work principle. The constitutive relations between dual variables are introduced defining a proper, convex, potential energy. It is proved that the solution of the elastic problem corresponds to a global minimum of the potential energy functional. Mo…
Habitat preferences of Bonelli's Eagles Aquila fasciata in Sicily
2012
Capsule For breeding, areas dominated by extensive agricultural and rugged Mediterranean landscapes are preferred; maintenance of habitat heterogeneity and extensive agriculture are key for the conservation of this eagle. Aims To model breeding habitat preferences of Bonelli’s Eagles Aquila fasciata in Sicily, where the last viable population still remains in Italy, in order to identify the most important habitats for conservation. Methods Pairs were monitored between 1990 and 2010. A case-control design through GLMs was used at two spatial scales: landscape and home-range. Variables included topographic, climatic, land-use, road and descriptors of habitat heterogeneity. Information-based c…
Analysis of Spatially and Temporally Overlapping Events with Application to Image Sequences
2006
Counting spatially and temporally overlapping events in image sequences and estimating their shape-size and duration features are important issues in some applications. We propose a stochastic model, a particular case of the nonisotropic 3D Boolean model, for performing this analysis: the temporal Boolean model. Some probabilistic properties are derived and a methodology for parameter estimation from time-lapse image sequences is proposed using an explicit treatment of the temporal dimension. We estimate the mean number of germs per unit area and time, the mean grain size and the duration distribution. A wide simulation study in order to assess the proposed estimators showed promising resul…
A Grain Boundary Formulation for the Analysis of Three-Dimensional Polycrystalline Microstructures
2013
A 3D grain boundary formulation is presented for the analysis of polycrystalline microstructures. The formulation is expressed in terms of intergranular displacements and tractions, that play an important role in polycrystalline micromechanics, micro-damage and micro-cracking. The artificial morphology is generated by Hardcore Voronoi tessellation, which embodies the main statistical features of polycrystalline microstructures. Each crystal is modeled as an anisotropic elastic region and the integrity of the aggregate is restored by enforcing interface continuity and equilibrium between contiguous grains. The developed technique has been applied to the numerical homogenization of cubic poly…
Coupled VEM–BEM Approach for Isotropic Damage Modelling in Composite Materials
2023
Numerical prediction of composite damage behaviour at the microscopic level is still a challenging engineering issue for the analysis and design of modern materials. In this work, we document the application of a recently developed numerical technique based on the coupling between the virtual element method (VEM) and the boundary element method (BEM) within the framework of continuum damage mechanics (CDM) to model the in-plane damage evolution characteristics of composite materials. BEM is a widely adopted and efficient numerical technique that reduces the problem dimensionality due to its underlying formulation. It substantially simplifies the pre-processing stage and decreases the compu…