Search results for "FD"

Modelling and simulation of gas-liquid hydrodynamics in mechnically stirred tanks

2007

Abstract Computational fuid dynamics (CFD) is an increasingly important tool for carrying out realistic simulations of process equipment. In the case of multiphase systems the development of CFD models is less advanced than for single-phase systems. In the present work CFD simulations of gas–liquid stirred tanks are reported. An Eulerian–Eulerian multi-fluid approach is used in conjunction with the simplest two-phase extension of the k–ɛ turbulence model. All bubbles are assumed to share the same size. The effect of inter-phase forces on simulation results is separately considered. As concerns drag, it is shown that the sole parameter needed to characterize the dispersed phase behaviour is …

Thermal-hydraulic behaviour of the DEMO divertor plasma facing components cooling circuit

2017

Abstract Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. A comparative evaluation study has been performed considering three different options for the cooling circuit layout of the divertor Plasma Facing Components (PFCs). The potential improvement in the thermal-hydraulic performance of the cooling system, to be achieved by modifying cooling circuit layout, has been also assessed and discussed in terms of optimization strategy. The research acti…

Imaging and biochemical biomarkers of psychiatric comorbidities in a rat epilepsy model

2018

Aims: Biomarkers of epilepsy-associated psychiatric comorbidities represent a powerful tool for an early diagnosis and personalized therapy in patients with epilepsy. Here, in order to identify new candidates as biomarkers of epilepsy comorbidities, alterations in brain metabolic activity and serotonergic neurotransmission in a rat post-status epilepticus model were explored and cross-correlated with alterations in various neurobehavioral and biochemical parameters. Methods: Status epilepticus was induced in twelve female Sprague Dawley rats by lithium chloride-pilocarpine treatment. µPET analysis to determine [18F]FDG uptake and [18F]MPPF binding were performed in the chronic phase of epil…

Etude numérique du comportement thermique d’un séchoir solaire utilisant un lit thermique pour le stockage d’énergie

2018

This thesis presents a numerical study of an indirect natural convection solar dryer for drying agricultural products (Figs). The first part analyzes a solar dryer containing a drying chamber coupled to a reversed absorber and a solar chimney. Simulations were made to determine the dynamic and thermal fields under the influence of the variation of the solar chimney configuration and the size of the inlet opening. The governing equations based on the standard k-ε turbulence model are solved by the finite volume method using the ANSYS-Fluent commercial code. The second part analyzes the effect of adding a thermal storage in the form of a gravel bed in the drying chamber. The bed is modeled as…

On improving the accuracy of Visible Light Positioning system using deep autoencoder

2020

International audience; DC-biased optical Orthogonal Frequency DivisionMultiplexing (DCO-OFDM)-based visible light positioning (VLP)technology along with the Received Signal Strength(RSS) po-sitioning algorithm is widely used to achieve centimeter levelpositioning accuracy for incoming 5G era, especially indoorenvironment. However, the DCO-OFDM has the peak-to-averagepower ratio (PAPR) issue which imposes the nonlinear distortionand it will directly affect the positioning accuracy in the VLPsystem. The PAPR reduction scheme is urgently needed. There-fore, in this paper, the impact of PAPR reduction scheme onpositioning accuracy is investigated. The positioning accuracywith and without the s…

ANALISI STRUTTURALE DI UN TIMONE PER ALISCAFI

2012

Attualmente i sistemi di controllo direzionale (timone) e di stabilità (flap) dei battelli veloci per il trasporto passeggeri (HSC) sono realizzati con elementi scatolari in acciaio. Ciò è essenzialmente dovuto alle notevoli sollecitazioni idrodinamiche che tali elementi sopportano a causa dell’elevata velocità di crociera. L’esigenza di ridurre il peso di tali elementi e di aumentarne la resistenza alle azioni corrosive esterne spinge ad una ricerca su materiali e tecnologie di fabbricazioni innovative. In questo studio è presentato il progetto di un timone, realizzato in materiale ibrido composito e acciaio, da impiegare su un battello per trasporto veloce passeggeri.

Analisi e sviluppo di imbarcazioni a sostentamento idrodinamico

Analysis and performance of FBMC techniques with application to relay networks

2014

Green Composites Based on Hedysarum coronarium with Outstanding FDM Printability and Mechanical Performance

2022

The addition of natural scraps to biodegradable polymers has gained particular interest in recent years, allowing reducing environmental pollution related to traditional plastic. In this work, new composites were fabricated by adding 10% or 20% of Hedysarum coronarium (HC) flour to Poly (lactic acid) (PLA). The two formulations were first produced by twin screw extrusion and the obtained filaments were then employed for the fabrication of composites, either for compression molding (CM) or by fused deposition modeling (FDM), and characterized from a morphological and mechanical point of view. Through FDM it was possible to achieve dense structures with good wettability of the filler that, on…

Hedysarum coronarium-Based Green Composites Prepared by Compression Molding and Fused Deposition Modeling

2022

In this work, an innovative green composite was produced by adding Hedysarum coronarium (HC) flour to a starch-based biodegradable polymer (Mater-Bi®, MB). The flour was obtained by grinding together stems, leaves and flowers and subsequently sieving it, selecting a fraction from 75 μm to 300 μm. Four formulations have been produced by compression molding (CM) and fused deposition modeling (FDM) by adding 5%, 10%, 15% and 20% of HC to MB. The influence of filler content on the processability was tested, and rheological, morphological and mechanical properties of composites were also assessed. Through CM, it was possible to obtain easily homogeneous samples with all filler amounts.…