Search results for "IMPIANTI"
showing 10 items of 797 documents
EXPERIMENTAL INVESTIGATION OF DILUTE SOLID-LIQUID SUSPENSION IN AN UNBAFFLED STIRRED VESSELS BY A NOVEL PULSED LASER BASED IMAGE ANALYSIS TECHNIQUE
2009
The availability of experimental information on solid distribution inside stirred tanks is a topic of great importance in several industrial applications. The measurement of solid particle distribution in turbulent multiphase flow is not simple and the development of suitable measurement techniques is still in progress. In this work a novel non-intrusive technique for measuring particle concentration fields in solid-liquid systems is employed. The technique makes use of a laser sheet, a high sensitivity digital camera for image acquisition and a Matlab procedure for post-processing the acquired images. Experimental data are here obtained for the case of an unbaffled stirred tank. Stable tor…
Vacuum air-lift bioreactor for microalgae production
2017
Microalgae production is receiving an increasing interest both by research institutions and commercial companies (Di Caprio et al., 2016). This is due to the growing consciousness of the need to move towards renewable, sustainable feedstoks for commodities production (Wang et al., 2012). However, process development at industrial scale, either based on open or closed photobioreactors, still is in a rather early stage and there is room for further development (Morweiser et al., 2010), especially aimed at reducing process costs. In this work an innovative low-cost technology for microalgae production, currently under development at Palermo University, is described. The main ways through which…
Valorization of waste solvents through supercritical water gasification
2017
The supercritical water gasification of various organic species belonging to the groups of organic acids, aldehydes, ketones, alcohols and phenols, has been studied as a possible waste disposal method for polluted water stream produced in industries and laboratories. Gasification has been investigated using a 200 cm3 down flow reactor working continuously at 24 MPa and 660 °C. Supercritical water gasification (SCWG) is effective for the syngas production at very high conversion rate for all the species investigates, but phenol. Phenol, when mixed with other species, has an inhibitory effect of the radical chain gasification mechanism that dramatically reduced the gasification performance. …
A multi objective approach to short food supply chain management
2017
Conventional supply chains, involving several stages and various intermediaries, are affected by some well- known forms of inefficiencies and drawbacks. Besides the increase of market price consequent to multiple marginalization, such supply chains generally suffer of significant post-harvest losses and product waste. In this context, short food supply chains have been recently proposed as different systems capable of delivering higher quality products while promoting sustainability and efficiency. Across the EU, a growing number of consumers choose to buy food products on local farmers' markets, associating local products with higher quality standards (freshness, nutritional value), health…
Sustainable vehicle routing based on firefly algorithm and TOPSIS methodology
2019
Abstract In a sustainable management of logistics, transportation plays a crucial role. Traditionally, the main purpose was to solve the Vehicle Routing Problem minimizing the cost associated with the travelled distances. Nowadays, the economic profit cannot be the only driver for achieving sustainability and environmental issues have to be also considered. In this paper, to satisfy the intricate limits involved in real vehicle routing problem, the study has been structured considering different types of vehicles in terms of maximum capacity, velocity and emissions, asymmetric paths, vehicle-client constraints and delivery time windows. The firefly algorithm has been implemented to solve th…
Combined effect of nutrient and flashing light frequency for a biochemical composition shift in Nannochloropsis gaditana grown in a quasi-isoactinic …
2020
Artificial lighting may be an interesting opportunity for the cultivation of microalgae as an alternative to natural sunlight. In particular, light emitting diodes (LEDs) can be employed to tailor the lighting to the microalgal culture in a controlled mode in order to create flashing light. In order to establish the effect of the flashing frequency on growth and biochemical composition of a model microalga, a quasi-isoactinic reactor, in which the light distribution is almost homogeneous, was set up. In this work, it was employed for the cultivation of the heterokont Nannochloropsis gaditana in two growth media with limiting and nonlimiting nutrients. The combined effect of nutrient concent…
Recent Progress in the WCLL Breeding Blanket Design for the DEMO Fusion Reactor
2018
The water-cooled lithium-lead (PbLi) breeding blanket is one of the candidate systems considered for the implementation in the European Demonstration Power Plant (DEMO) nuclear fusion reactor. This concept employs PbLi liquid metal as tritium breeder and neutron multiplier, water pressurized at 15.5 MPa as the coolant, and EUROFER as the structural material. The current design is based on the single module segment approach and follows the requirements of the DEMO-2015 baseline design. The module is constituted by a basic toroidal-radial cell that is recursively repeated along the poloidal direction where the liquid metal flows along a radial-poloidal path. The heat generated by the fusion r…
A GENERAL COMPUTATIONAL APPROACH FOR MAGNETOHYDRODYNAMIC FLOWS USING THE CFX CODE: BUOYANT FLOW THROUGH A VERTICAL SQUARE CHANNEL
2000
The buoyancy-driven magnetoconvection in the cross section of an infinitely long vertical square duct is investigated numerically using the CFX code package. The implementation of a magnetohydrodynamic (MHD) problem in CFX is discussed, with particular reference to the Lorentz forces and the electric potential boundary conditions for arbitrary electrical conductivity of the walls. The method proposed is general and applies to arbitrary geometries with an arbitrary orientation of the magnetic field. Results for fully developed flow under various thermal boundary conditions are compared with asymptotic analytical solutions. The comparison shows that the asymptotic analysis is confirmed for hi…
A Multi-Criteria Group Decision To Support The Maintenance Service: A Case Study
2015
The present paper wants to propose a methodology to support a group of decision makers into the choice of actions, to implement on a multi-component system, regarding the maintenance service. The choice has to be made on the basis of several criteria, namely the total maintenance cost, the system unavailability and by considering the maintenance actions feasibility. In particular, with the aim to select the maintenance service that represents for the group the best comprise among the criteria to satisfy, the proposed methodology consists of two multi-criteria decisions methods to apply in two successive phases. The first one regards the application of the Analytic Hierarchy Process (AHP) to…
IMPIANTO DI STABILIZZAZIONE DI UNA IMBARCAZIONE A SOSTENTAMENTO ALARE
2012
Lo studio, frutto dell’attività di ricerca svolta dal DICGIM dell’Università degli Studi di Palermo in partnership con l’Engineering Department della Ustica Lines S.p.A. nell’ambito di un progetto finanziato con fondi PON Ricerca e Competitività 2007-2013, analizza preliminarmente le cause di guasto comportanti la fermata di un battello a sostentamento alare HSC per trasporto passeggeri al fine di individuare i componenti critici del mezzo. Individuato tale componente nel sistema di stabilizzazione, viene valutato l’impatto economico che il fermo del battello comporta sui costi operativi della Compagnia di navigazione. L’entità di tali costi, anche in termini di mancata utilizzazione del me…