Search results for " INGEGNERIA"
showing 10 items of 796 documents
An integrated model for physical-biological wastewater organic removal in a submerged membrane bioreactor: Model development and parameter estimation
2008
The paper presents the setting up of a mathematical model for membrane bioreactor able to simulate physical-biological wastewater organic removal. The model is basically divided into two sub-models: the first sub-model is basically devoted for the simulation of the biological features and the second one for the physical processes. In particular regarding the biological aspects, the ASM concept has been employed. On the other hand, the physical processes have been modelled considering the deep-bed theory taking into account not only the effect of the physical membrane filtration but also the cake layer effect. This latter operates as a biological membrane leading to a further reduction of th…
REWAQUA: an advanced technology for water purification in sustainable aquaculture based on photocatalytic ozonation
2017
The present study has been undertaken in order to test the real potential of photocatalytic ozonation in a bench-scale recirculating aquaculture system working on a 180 L reef coral aquarium. Notably, this choice may be considered representative. In fact, (i) the system is virtually closed so that fresh water turnover is practically negligible, (ii) the presence of living organisms is highly diversified (corals, fishes, molluscs, echinoderms and crustaceans) and some of them are particularly sensitive to water quality, (iii) high salinity strongly puts a strain on the purification system. The hereby presented purification method has been named REWAQUA, which stands for REcycling Water for A…
Prediction of flow fields in a dual-impeller stirred vessel
1999
Numerical simulations were connected for the flow field in a baffled tank stirred by a dual Rushton impeller. For this geometry, LDV measurements show a characteristic dependence of the flow patterns upon the position of the impellers. Two advanced modeling approaches were tested. In the first, the vessel was divided info two concentric blocks, coupled by, a sliding grin technique, and simulations were conducted in time-dependent mode. In the second approach, the vessel was modeled as two partially over-lapping I regions, the inner one rotating with the impeller and rite outer one stationary simulations were run in steady-state mode for each of the two regions, while information was iterati…
Coupling CFD with a one-dimensional model to predict the performance of reverse electrodialysis stacks
2017
Abstract Different computer-based simulation models, able to predict the performance of Reverse ElectroDialysis (RED) systems, are currently used to investigate the potentials of alternative designs, to orient experimental activities and to design/optimize prototypes. The simulation approach described here combines a one-dimensional modelling of a RED stack with a fully three-dimensional finite volume modelling of the electrolyte channels, either planar or equipped with different spacers or profiled membranes. An advanced three-dimensional code was used to provide correlations for the friction coefficient (based on 3-D solutions of the continuity and Navier-Stokes equations) and the Sherwoo…
A strategic framework for firm networks in manufacturing industry: An empirical survey
2009
Firm networking is becoming more and more the most important competitive strength in nowadays competitive environment. Such an evidence is partially neglected by the classical strategic analysis of firms competitiveness which mainly looks at the firm strength and weakness not in relationship with its capacity to build competitive networks. For such a reason, in the last years, many theoretical approaches have stressed the importance of networks to gain competitive advantage. In this paper, the most significant theories on firm networking are reviewed and an innovative strategic framework that mainly underlies at firm networks organisation is proposed. Very briefly, it is argued that network…
High Level Planning of Reconfigurable Enterprises: a Game Theoretic Approach
2006
Reconfigurable Enterprises (REs) represent production networks made of different and geographically dispersed plants that, in case of unpredictable market changes, can be reconfigured in order to gather a specific production objective. However, REs effectiveness and efficiency depend on the extent to which global performance is obtained. Basically two approaches are available to reach coordination: centralised or decentralised planning tools. In this paper, the authors propose a novel cooperative game theoretical approach for distributed production planning at high level of a RE; the proposed approach has been benchmarked in front of both a distributed one, based on negotiation, and a centr…
Distributed intelligent control of exceptions in reconfigurable manufacturing systems
2003
In order to react to the continuous and unpredictable changes in product demand, in product variety, and in process technologies, reconfigurable manufacturing systems allow quick adjustment of production capacity and functionality by rearranging or changing their modular components. In this kind of system, operation management issues, such as exception handling policies, become more complex since correct reconfiguration strategies have to be selected. This paper explores the potential of the reconfigurability feature to be a basis for the development of new strategies to handle out-of-the-ordinary events in the production process; in particular, maintaining production flow when machine brea…
Reconfigurable control of robotized manufacturing cells
2007
This paper investigates the field of manufacturing system control. The addressed subject is indeed very fascinating, due to the importance that it has reached in the last decades both at research and industrial level. On the other hand, it seems to the author that most of the complexity intrinsic to the subject itself relies on the different meanings or levels of abstraction that both the terms ''manufacturing system'' and ''control'' may symbolize. The presented research aims to face the topic in a concrete fashion, i.e., by developing a control software system for a specific, although easy to be generalized, robotized manufacturing cell. Two different development methodologies, from the c…
Unveiling the distinctive role of titanium dioxide nanoparticles in aerobic sludge digestion.
2022
Abstract Aerobic digestion is considered to be a common process for the stabilization of waste activated sludge (WAS) in the small-sized wastewater treatment systems, while the broad application of titanium dioxide nanoparticles (TiO2 NPs) results in their unavoidable existence in WAS aerobic digestion, with its role in aerobic sludge digestion being never documented. This study set up a series of aerobic sludge digesters to evaluate the previously unknown role of TiO2 NPs on the performance of the digesters. The volatile solids (VS) degradation percentage increased from 21.9 ± 0.6% to 26.9 ± 0.1% − 30.0 ± 0.3% with the different contents of TiO2 NPs (0, 1, 20 and 50 mg/L). Similarly, the t…
Dewaterability of CAS and MBR Sludge: Effect of Biological Stability and EPS Composition
2018
The dewaterability of sludge from two conventional activated sludge (CAS) and three membrane bioreactor (MBR)-based wastewater treatment plants is investigated prior to and after anaerobic digestion. The concentration and composition of extracellular polymeric substances (EPS) mostly affect the dewaterability of all raw sludge samples. Better sludge dewaterability is observed when the concentration of proteins, carbohydrates, uronic acids, and humic acids is below approximately 400, 250, 200, and 40 mg/L, respectively. In contrast, the specific resistance to filtration (SRF) increases in the sludge samples with a higher EPS concentration. The MBR results in a lower EPS production and a uron…