Search results for "Modell"
showing 10 items of 2134 documents
Lettura stratigrafica degli elevati e restituzione 3d della Chiesa
2009
Il contributo riguarda lo studio architettonico della chiesa attraverso un percorso metodologico che parte del rilievo architettonico e dalla lettura stratigrafica degli elevati fino all'ipotesi di ricostruzione virtuale dell'edificio The contribution concerns the architectural study of the church through a methodological path that is part of the architectural survey and from the stratigraphic reading of the elevated to the hypothesis of virtual reconstruction of the building
Mass appraisal of residential real estate using multilevel modelling
2016
Mass appraisal, or the automatic valuation of a large number of real estate assets, has attracted the attention of many researchers, who have mainly approached this issue employing traditional econometric models such as Ordinary Least Squares (OLS). However, this method does not consider the hierarchical structure of the data and therefore assumes the unrealistic hypothesis of the independence of the individuals in the sample. This paper proposes the use of the Hierarchical Linear Model (HLM) to overcome this limitation. The HLM also gives valuable information on the percentage of the variance error caused by each level in the hierarchical model. In this study HLM was applied to a large dat…
Simplified dynamic pressure method for kLa measurement in aerated bioreactors
2010
Abstract A simplified version of the dynamic pressure method for measuring mass-transfer coefficients in gas–liquid systems is proposed. With this method oxygen concentration in the liquid phase is monitored after a sudden change of total pressure is applied to the system. With respect to the original technique introduced by Linek [14] the simplified version here proposed greatly simplifies the data treatment, yet resulting in good accuracy for most practical purposes. In practice, with the help of a simple mathematical model, it is found that the dynamic oxygen concentration response, when plotted as residual driving force versus time in a semi-log diagram, should be expected to finally se…
11B-MAS NMR approach to the boron adsorption mechanism on a glucose-functionalised mesoporous silica matrix
2018
[EN] Boron chemistry has raised much interest because, despite the difference between necessities and toxicity being very narrow, it is still widely used in industrial processes. In a previous work we reported an adsorbent for boron extraction from water by the functionalisation of a UVM-7 mesoporous silica matrix with gluconamide moieties. The ability of this material to adsorb boron is based on its well-known affinity for coordinating the cis-diols present in attached saccharide. Although much research on the formation of boron esters with sugars and sugar derivatives in solution has been done, very few reports have dealt with the adsorption mechanism of boron onto functionalised material…
Development and analysis of a model based on chirped fiber Bragg gratings employed for cracks characterization in materials
2018
In this work a model was developed that allows to understand the behavior of a chirped fiber Bragg grating for the detection and characterization of cracks in materials. In addition to the amplitude response, we show that the group delay of the grating provides useful information for the characterization of the crack. The position of the crack can be determined thanks to the linear chirp of the grating that fixes a correlation between the spatial position and both, the wavelength and the group delay. However, our analysis shows that this simple approach has a source of error, which can be overcome if a controllable external strain can be applied to the embedded grating, additional to the st…
Numerical simulations of the mechanical characteristics of glass fibre reinforced C-profiles
2006
A mechanical characterisation analysis on pultruded glass fibre reinforced C-shaped profiles, developed as modular construction elements to assemble fastening systems, such as doors, window frames and shutters is presented. The key idea is to perform the analysis, and all the related identification procedures of the material parameters, via a coupled approach, based on a limited number of standard laboratory tests and on the numerical finite element simulations of the same tests. The proposed approach allows one to identify all those material parameters which are difficult to detect, by means of simple laboratory experiments on specimens that are extracted from commercial products. It also …
High-dose behaviour of CaSO4: Dy thermoluminescent phosphors as deduced by a continuous model for trap depths
1978
Abstract The high-dose behaviour of CaSO4: Dy TL dosimeters observed by some authors is compared with the one deduced by the continuous distribution of trap depths previously proposed by us. A general agreement results.
Determination of lifetime probabilities of carbon fibre composite plates and pressure vessels for hydrogen storage
2011
International audience; It is shown that an analogy can be made between the failure of unidirectional carbon fibre reinforced epoxy plates and filament wound carbon fibre composite pressure vessels and that their strengths and failure probabilities can be determined. Fibres in filament wound composite structures are placed on geodesic paths around the mandrel, which becomes the liner; so that when the structure is pressurised the fibres are only subjected to tensile forces, as in a unidirectional composite. Multiscale modelling reveals that composite failure is controlled by fibre breakage and that clustering of fibre breaks determines ultimate reliability of the structure. Time dependent r…
Visual indicator for the detection of end-of-life criterion for composite high pressure vessels for hydrogen storage
2012
International audience; A model to predict the accumulation of fibre breaks in advanced composites, that takes into account all physical phenomena implicated in fibre failure (i.e. the random nature, stress transfer due to breaks, fibre debonding and viscosity of the matrix) shows clearly that the failure of a unidirectional composite structure results in the formation of random fibre breaks which at higher loads coalesce into clusters of broken fibres. This stage of development is followed almost immediately by failure. This has direct application to filament wound pressure vessels of the type used to store hydrogen under high pressure. A novel, cost effective, method of revealing developi…
Cohesive–frictional interface constitutive model
2009
AbstractIn the framework of numerical analysis of joined bodies, the present paper is devoted to the constitutive modeling, via an interface kinematic formulation, of mechanical behaviour of internal adhesive layers. The proposed interface constitutive model couples a cohesive behaviour, based on the damage mechanics theory, with a frictional one, defined in a non-associative plasticity framework. Namely, the interface formulation follows the transition of the adhesive material from the sound elastic condition to the fully cracked one. This formulation is able to model, by means of a specific interpretation of the damage variable and in a relevant mathematical setting, the interface interme…