Search results for "SVI"
showing 10 items of 4456 documents
Membrane distillation: Solar and waste heat driven demonstration plants for desalination
2013
Abstract The development of small to medium size, autonomous and robust desalination units is needed to establish an independent water supply in remote areas. This is the motivation for research on alternative desalination processes. Membrane distillation (MD) seems to meet the specific requirements very well. This work is focused on experimental studies on full scale demonstration systems, utilizing a parallel multi MD-module setup. Three different plant concepts are introduced, one of them is waste heat driven and two of them are powered by solar thermal collectors. Design parameters and system design are presented. After the analysis of plant operation a comparison among the plants as we…
CFD simulations of dense solid–liquid suspensions in baffled stirred tanks: Prediction of solid particle distribution
2013
Abstract Industrial tanks devoted to the mixing of solid particles into liquids are often operated at an impeller speed N less than Njs (defined as the lowest speed allowing the suspension of all particles): under such conditions the distribution of solid-particles is very far from being homogeneous and very significant concentration gradients exist. The present work is devoted to assessing the capability of Computational Fluid Dynamics (CFD) in predicting the particle distribution throughout the tank. The CFD model proposed by Tamburini et al. [58] and successfully applied to the prediction of the sediment amount and shape was adopted here to simulate the particle distribution under partia…
Steady State and Dynamic Models of Multistage Flash Desalination: A Review
2010
This article focuses on a review of literature studies on steady state and dynamic modeling of the multistage flash desalination process (MSF). The review shows that both steady state and dynamic models are based on lumped parameter approach. Differences in literature models are found in the assumptions used to model the flashing stage in addition to the correlations used to determine the heat transfer coefficients, thermodynamic losses, thermodynamic and transport properties. Interestingly, literature indicates a rapid progress made in software used for coding and solution of the model equations. The review shows a limited number of literature models for the internals of the flashing stage…
Development of a Membrane Distillation module for solar energy seawater desalination
2012
Abstract Membrane Distillation (MD) processes are gaining growing interest among novel desalination technologies, in particular for small scale applications also coupled with non-conventional energy sources. In the present work an original laboratory scale planar geometry Membrane Distillation unit was designed, built and tested for future coupling with solar energy. Though conceptually simple, the original geometry was developed in order to allow for multi-stage arrangement, compactness, internal heat recovery and possible integration with a polymeric heat exchanger for final brine heating by means of solar energy or waste heat. The laboratory scale unit was tested in order to investigate …
Control of the Biodegradation of Mixed Wastes in a Continuous Bioreactor by a Type-2 Fuzzy Logic Controller
2009
Abstract Type-2 fuzzy logic control is proposed for nonlinear processes characterized by bifurcations. A control simulation study was conducted for a bioreactor with cell recycle containing phenol and glucose as carbon and energy sources in which a pure culture of Pseudomonas putida is carried out. The model developed by Ajbar [Ajbar, A. (2001). Stability analysis of the biodegradation of mixed wastes in a continuous bioreactor with cell recycle. Water Research, 35 (5), 1201–1208] was used for the simulations. The particular dynamics of the bioreactor, characterized by two saddle-node bifurcations, makes its control difficult, since it may become unstable also for small variations of some p…
Particle distribution in dilute solid liquid unbaffled tanks via a novel laser sheet and image analysis based technique
2013
The availability of experimental information on particle distribution inside stirred tanks is a topic of great importance for many industrial applications such as catalysis and polymerization. The measurement of solid particle distribution is not simple and the development of suitable measuring techniques is still an open problem in chemical engineering research. In this work, a non-intrusive optical technique for measuring particle concentration fields in solid–liquid systems is discussed. The “Laser Sheet Image Analysis” (LSIA) technique described here makes use of a laser sheet, a digital camera for image acquisition and a suitable procedure for post-processing. It is able to provide sol…
A description model for regeneration through urban tourism in rural towns with underused historic real estate
2016
Il presente contributo propone un modello di descrizione (description model) che trova applicazione in una situazione reale di aiuto alla decisione posto dall'urbanista per lo sviluppo turistico delle città rurali nelle zone dell'entroterra siciliano. Il problema decisionale riguarda la città di Cianciana (AG), che negli ultimi anni si è resa protagonista di un particolare fenomeno di turismo internazionale. In particolare, proponiamo un quadro valutativo multicriteriale per la riqualificazione fisica ed economica del centro storico della città attraverso lo sviluppo del turismo. Il modello presentato, relativo a un problema decisionale di tipo descrittivo, è orientato a supportare i deciso…
Ambizioni e insuccessi di alcune politiche di sviluppo locale per il Mezzogiorno. Patti territoriali e Programmi integrati territoriali (Pit)
2008
In 1997 a “new programming” was launched in Italy by the Department of development and cohesion policies in Rome. One of the key features of this new phase was the emphasis on “endogenous” local development, i.e. a development which is mainly based on local actors and productive specializations. The new programming strikingly failed to deliver its expected results. Some wrong expectations were fostered with regard to local political elites (§§ 1). A certain concept of local development is inherently flawed (§§ 2). The first failure was that of “territorial agreements” (patti territoriali), but there is a remarkable reluctancy to admit it (§§ 3). Another experience of “local” development who…
Sustainable Development Goals in Strategy and Practice: Businesses in Colombia and Egypt
2021
Businesses may adopt strategies and practices that support sustainable development goals. Such strategies include considering social and environmental impacts as well as prioritizing socio-environmental benefits at a higher level than profits. Supportive practices comprise enhancing social benefits and limiting environmental harm. What SDG-related strategies and practices are businesses pursuing? Are businesses implementing practices and strategies? Do the practices and strategies differ across societies? A survey of representative samples of 399 businesses in Colombia and 413 businesses in Egypt was conducted in 2021, by the Global Entrepreneurship Monitor. The owner-managers reported that…
Entrepreneurs’ interpersonal communication competence in networking
2020
Modern international business calls for competencies that enable entrepreneurs to be creative, innovative, effective and capable of networking. Competencies in forming and developing networks are particularly valuable for organizations and companies in countries with small economies, such as Finland, that are dependent on export and profitable international business. The aim of this research is to build understanding of what kind of interpersonal communication competence (ICC) entrepreneurs need in networking.
 Since the classic work of Granovetter (1982) and others (see e.g. Håkansson, 1982; Håkansson & Snehota, 2000), network theory and network analysis have become popular when t…