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Computational fluid dynamics and experimental study of the hydrodynamics of a bubble column and an air-water jet-stirred cell
Get PDFA large number of flows encountered in nature and in many industrial processes areintrinsically multiphase flows. The efficiency and the effectiveness of multiphase flow
processes strongly depend on the ability to model the fluid flow behaviour. Thus, a robust and accurate description of multiphase flow can lead to an increase in performance, a
reduction in cost, and an improvement in safety for engineering systems. In recent years, Computational Fluid Dynamics (CFD) has become an indispensable predictive tool for gathering information to be used for design and optimization for fluid systems. In this thesis the hydrodynamics of two bubbly flow systems, a bubble column and a waterjet-agitated flotation cell (Hydrojet cell), were studied by means of numerical simulations. In
order to validate the bubble column CFD simulations Particle Image Velocimetry (PIV) was used. An experimental investigation about bubble size distribution (BSD) along a water jet was carried out by means of image analysis. Because of high gas fraction and high velocity of
the air/water streams used to agitate the Hydrojet cell, with the available equipment, no experimental measurements could be done to evaluate the velocity field of the cell.
The thesis consists of three parts: theoretical part, bubble column study and Hydrojet cell study. In the theoretical part, first, a summary of fluid dynamics principles and an overview of the principal issues related to multiphase flow modelling were presented. Then a brief
introduction to PIV and its application to two phase bubbly flow were given. Finally a review of the principle of the flotation process and its modelling were done in order to highlight the reasons for the low recovery of fine particles. Then the potentialities offered by the use of
waterjets to fine particles flotation were presented.
In the second part experimental and numerical studies of a bubble column were presented. PIV technique was used to determine the velocity field of a laboratory bubble column. A separation method for multiphase PIV was developed and tested. By means of the proposed method, the acquired mixed-fluid images were processed to obtain two sets of single phase images before PIV analysis. The velocity field was determined using a multi-pass crosscorrelation.
Following three-dimensional time-dependent CFD simulations of a lab-scale bubble column were presented. The simulations were carried out using the Euler - Euler
approach. Two different multiphase turbulence models, Shear Stress Transport (SST) and Large Eddy Simulation (LES), were tested, and different interfacial closure models reported in the literature were examined. When LES were used to model the turbulence instead of the
SST model, much better agreement with the experimental data was found, provided that the drag, lift and virtual mass forces were taken into account. In the third part a preliminary experimental study, carried out in a rectangular flat cell, was presented. It was carried out to investigate the size distribution of bubbles generated by a
moderate pressure water jet, by means of image analysis. This study showed the ability of water jets at moderate pressure to break an air stream into small bubbles. Increasing the pressure of the pump, smaller and more uniform bubbles were obtained. Then three-dimensional CFD simulations of the Hydrojet cell are presented. The Hydrojet
cell, due to the exceeding computational burden, was simulated as a two-phase (gas-liquid) system, although actually it is a three-phase (gas-liquid-solid) system. Also in this case simulations were carried out using the Euler - Euler approach. The turbulence of the liquid
phase was modelled with the SST model. The single reference frame technique was used to describe the movement of the waterjet lance. To achieve a homogeneous aeration in the
region near the inlets different inlet velocity and rotational speed were tested. The results gave useful indications about the role of the four principal operating parameters: nozzles diameter, velocity of rotation of the lance, speed of the water jets and then pressure of the
pump and inlet air flow rate. What emerges is the need of high rotational speed of the waterjet lance in order to ensure an uniform gas distribution within the mixing zone. This is not possible with the current apparatus. Thus in order to make the system suitable to produce an appropriate environment for the full development of the flotation process it is necessary to modify the system
L'attività motoria acquatica come nuovo approccio terapico alla cardio-diabetologia
Get PDFThe role of general physical activity on improving cardiometabolic profile and quality of life in patients with type 2 diabetes is widely demonstrated. However, little is known about the effects of specific water exercise program in patients with type 2 diabetes. Therefore, the aims of this pilot study were to evaluated the effects of a supervised water training program in subjects affected by type 2 diabetes. Methods: eighteen men affected by type 2 diabetes (51,4±9,38 years), were enrolled in a program of 12 weeks of supervised water training. We assess Cardiometabolic Profile (echocardiography, glycemic, lipidemic and anthropometric profille, blood pressure levels and cardiopulmonary exercise test), and Quality of Life and Physical Activity Levels (Short-form Health Survey 36 with items (SF-36), Problem Areas in Diabetes Questionnaire (PAID) and International Physical Activity Questionnaire (IPAQ)) before and after 12-weeks of a supervised water exercise program. Results: The results showed a significant improvement of cardiovascular and metabolic assessments (aerobic capacity, work, blood pressure, glycemic,
anthropometric and lipidemic profile, and diastolic function) and an increasing in quality of life and physical activity levels (Sf-36, PAID, energy expenditure in general
physical activity). Discussion: Our findings showed that structured and supervised physical activity
performed in water, produced benefits both in improving of the cardiometabolic profile and the HRQoL and also in increasing of the physical activity levels in subjects affected by type 2 diabetes
Volte Tardogotiche sarde: disegno, misura, materia
Get PDFThe thesis investigates the way how the Sardinian late Gothic vaults were built. The previous opportunities of study reinforced the need to explore this specific topic within the broad field of the Sardinian late Gothic architecture, which covers a period between the fourteenth and the seventeenth century. The aspects of research are numerous because of the large number of architectures of this kind on the island. Each of this aspect is rich in possible facets of analysis. However, the problem of vaulted roofs appear the most complex and varied both for the large number of cases available and for the opportunity to deepen the close link between the Sardinian buildings and those of Catalonia. A link already pointed out by many scholars of architectural history. The thesis highlights this link not delving into the historical aspects but especially using drawing as a tool of knowledge and inquiry.
The drawing is the development tool of all the work. It contributed to the phase of territorial analysis as an instrument for the graphic display of census data. It was the tool of analysis of the vault construction and the stereotomic practice. Drawing allowed the visual interpretation of the project and the theoretical representation of the volume. Finally, the drawing appears as an inquiry element about the dimensions, as a transcription tool of the survey operations, as an instrument for the geometric and dimensional comparison.
The focus of the work is certainly the survey and documentation phase which took place on two different levels. A general documentation level describes the phenomenon and draws up a catalog of late gothic buildings with ribbed vaults. A detail documentation levels makes a thorough analysis of several case studies. In parallel to the problems related to the architectural survey, each phase of work has also addressed the inherent aspect of the building material in order to: shed light on the different solutions adopted in relation to the workability of the material, and to identify, as far as possible, the extraction sites of the materials used in the analyzed cases. The work is divided into successive stages:
framework of the problem that highlights the potential and shortcomings of the state of the art on the subject. The path of inquiry has been drawn to provide an initial understanding of the phenomenon in the area and identify the connection points with the regions of Spain from which was imported the constructional praxis. organization of the census and analysis of results. The data are organized into a GIS system and are designed to be queried to obtain cartographic representations that ensure an immediate visual analysis of the collected data. The census has allowed the identification of a large number of buildings on the entire region. A summary sheet has been prepared for each building. The census showed the ubiquity of the spread and the variety of building materials, even in relation to the geological diversity of the island. analysis of aspects related to the construction of the vault. Real cases were correlated with the theoretical ones obtained by encoding the treaties of stereotomy and construction published in Spain in the sixteenth century. At this stage, the relationship between the construction technique and the building materials were examined on the basis of information gathered during the census. elaboration and application of the survey process. The objective of this phase was to define and apply a survey method that allowed the rapid but accurate measurement and restitution of numerous case studies identified according to criteria of homogeneity related to dating, construction material and geographic area. The survey method developed has allowed to test the application of the Image Based Modelling software in the documentation of interior spaces. The procedure was refined to make it suitable in documenting Sardinian late Gothic vaults that have size and shape well suited to the specifications required by the software. The procedure has been tested on a large number of vaults so it was possible to highlight the strengths and limitations of the method and establish a protocol for the documentation of other similar vaults.
The work ends with a dimensional comparison between the measured vaults, highlighting similarities and differences with the theoretical cases described in the Spanish construction treaties. Finally, the recurring characteristics have been identified for the decorative elements. This latter aspect outlines possible future developments of the research, which could evolve in the analysis of the stone work and the comparison between the moldings and decorative elements that most characterize keystones, capitals and corbels
Studio microstrutturale e magnetico di nanocomposti innovativi a matrice silicea mesoporosa
Get PDFThis study deals with the characterization of innovative nanostructured composite materials made out of nanocrystals based on transition metals dispersed on an highly porous amorphous silica matrix. In particular, the research has been focused on the morphological, structural, compositional, and magnetic investigation of two series of nanocomposites: mesoporous ordered silica SBA16 containing iron-cobalt alloy nanocrystals, and silica aerogel embedding zinc ferrite nanocrystals. The materials have been investigated both by conventional (bright field and dark field imaging, electron diffraction) and advanced (high resolution transmission electron microscopy,
and high resolution scanning electron microscopy in high annular angle dark field mode) electron microscopy techniques. Scanning transmission measurements have been combined with simultaneous X-ray energy dispersion spectroscopy measurements. The results obtained
from the microscopy investigation have been compared with the information obtained by the Xray diffraction study of the same materials. The magnetic behavior has been investigated by ZFC-FC static and dynamic magnetization
measurements, by thermoremnant magnetization, by isothermal hysteresis cycles, and by Mössbauer spectroscopy.
The ZFC-FC experimental magnetization curves have been fitted though a simplified model by a FORTRAN code which has been defined, optimized, and implemented with a user-friendly graphic interface. The aim of this study it to highlight the key role of advanced characterization in determining and interpreting the chemico-physical properties of nanocomposite innovative materials. The two series of materials investigated in this work have been selected mainly in view of the peculiar morphological features of the porous matrix (silica aerogel and mesoporous silica with cubic symmetry) as well as in view of the functional catalytic and magnetic) properties of the
resulting nanocomposite. The results enabled to define the features of the nanocomposites responsible for their
functional properties, such as: composition, crystallinity, shape, size and size distribution of the nanophase, and its dispersion within the porous matrix. Particular attention has been given to the correlation between chemico-physical features of the nanocomposites and interpretation interpretation and prediction of the magnetic behavior
Depositional and welding processes in low aspect ratio ignimbrites: examples from the Sulcis Volcanic District(Sardinia, Italy)
Get PDFThe rheomorphic, high-grade, welded ignimbrites are a special type of pyroclastic density current (PDC) deposits usually associated with high intensity volcanic explosive activity (VEI >4). They are characterized by a high variability of physical features and sedimentological structures that may testify different emplacement mechanisms from a PDC and a different response to topography during and after the end of the depositional processes. When the temperatures of the deposits are higher than the glass transition temperature (Tg) and the deposits stay hot for long periods, they can undergo important local readjustments. The purpose of this PhD thesis is to investigate the processes which control the deposition and deformation of rhyolitic to comenditic welded ignimbrites, how and when the different processes occurred and which factors influenced the formation of the main structures.
The Sulcis Volcanic District (SW of Sardinia - Italy) is a good field laboratory where sixteen, well exposed, well conserved and not affected by recent tectonic processes, welded ignimbrites crop out. All these features permit to study and analyze the main processes, despite their Miocene age. The research focalized its attention on three ignimbritic units: Punta Senoglio Unit, Ventrischio Unit and Monte Ulmus Unit. In particular, attention was pointed on the Monte Ulmus Ignimbrite (MUI), where all these processes are particularly well recorded along the numerous available outcrops . A systematic and detailed study of the deposits was carried out. The description at different scales of the main features of the deposits and the analysis of the products with different methodologies, permitted to recognize the main eruptive phases and the main processes driving the formation of the ignimbrite, together with their relative timing. The deposits of all the three studied ignimbrites show evidences of syn- and post-emplacement welding and rheomorphism. The analysis of the micro-structural features on thin sections clear evidences an upward variations in strain rate, suggesting deposition varying from gradual to step-wise aggradation.
The MUI well preserves primary structures typical of high grade ignimbrites (foliations, lineations, welding and facies variations), structures typical of rheomorphic ignimbrites (rotated solid fragments, different scale folds, ramps, etc) and structures related with cooling and degassing processes (blisters, degassing pipes, devitrification facies). The MUI is a high-grade, rhyolitic to trachytic, locally rheomorphic, low-aspect-ratio welded ignimbrite. It crops out mainly in Sant’Antioco and San Pietro islands and in the Sulcis, on an area of 300 km2 with a minimum estimated volume of 2.5 km3. The most likely position of the source area is in the northern sector, few kilometers N of the San Pietro Island. Four main pyroclastic flow units (in the sense of Smith 1960) that cooled together, named A0, A1, A2 and B and preceded by a basal fall-out deposit (F), have been distinguished. In addition, seven main lithofacies were recognized inside the MUI, reflecting the different flow regimes of PDC (from turbulent to laminar) and the different depositional processes (from gradual to step-wise aggradation). All the described lithofacies are suggestive of welding and deformation processes are syn- and post emplacement. MUI physical features are strongly related to the paleotopographic conditions (topographic highs, topographic lows or flat conditions). Locally, the deposits record quick syn-emplacement en-masse readjustment, also on gently dipping slopes (~10°), probably due to generally low viscosity of the products or to the large amount of gas entrapped inside the deposits. The low values of Tg estimated for the MUI products ( ~415 °C) possibly resulted in protracted, nearly plastic conditions of the deposits, enhancing the remobilization of the deposits also during the final phases of emplacement.
The first, turbulent, steady flows were characterized by high depositional rates and the related deposits were emplaced by gradual aggradation. The flows became progressively laminar with the increase of the run-out, and different traction carpets were emplaced en-masse by step-wise aggradation. The second half of eruption was characterized by an unsteady mass flow, possibly related with a caldera-forming phases. The deposits grew up by quick gradual aggradation from laminar flows. Welding processes of the upper portion of MUI are mainly post-emplacement and they were driven principally by lithostatic load
Sintesi e caratterizzazione di nanocompositi aerogel altamente porosi per applicazioni catalitiche
No full textThis thesis has focused on the synthesis, characterization and catalytic applications of nanocomposite aerogels, made out of an active nanophase dispersed in a highly porous
amorphous silica matrix. These nanocomposites have unique properties which mainly depend on the composition, size and distribution of the nanoparticles and on the morphology and porosity of the matrix. Highly porous MFe2O4-SiO2 (M = Co, Ni, Mn, Zn), NiCo2O4-SiO2, Fe/Mo-SiO2, CuO-SiO2, Cu2O-SiO2 e
Cu-SiO2 nanocomposite aerogels, with variable amounts of dispersed phase, were prepared by a sol-gel procedure followed by supercritical drying and thermal treatments. This method is based on the co-hydrolysis and co-gelation of the precursors of the matrix and the dispersed phase
through the pre-hydrolysis of the TEOS (tetraethoxysilane) under acid conditions followed by gelation under basic conditions, using urea as gelling agent. The detailed characterization of nanocomposite aerogels was carried out using a multitechnique approach involving conventional techniques, such as X-ray diffraction (XRD), nitrogen
physisorption at 77 K and transmission electron microscopy (TEM), associated with more advanced techniques such as X-ray absorption spectroscopy (XAS), Mössbauer spectroscopy and SQUID magnetometry. These nanocomposites, thanks to their high porosity, low density and high area surface, were
tested as catalysts in important industrial processes such as the synthesis of Carbon Nanotubes via Catalytic Chemical Vapour Deposition (CCVD) and the Water Gas Shift Reaction (WGSR), which plays an important role in the technology of fuel cells (FC), showing interesting catalytic activities.
The tests for multiwall carbon nanotubes (MWCNT) production and for WGSR were performed in collaboration with the Applied and Environmental Chemistry Department of Szeged University (Hungary), the Chemistry Department of Rome University “La Sapienza” and the Chemical and Earth Science Department of Cagliari University
Combining FPGA prototyping and high-level simulation approaches for Design Space Exploration of MPSoCs
Get PDFModern embedded systems are parallel, component-based, heterogeneous and finely tuned on the basis of the workload that must be executed on them. To improve design reuse, Application Specific Instruction-set Processors (ASIPs) are often employed as building blocks in such systems, as a solution capable of satisfying the required functional and physical constraints (e.g. throughput, latency, power or energy consumption etc.), while providing, at
the same time, high flexibility and adaptability. Composing a multi-processor architecture including ASIPs and mapping parallel applications onto it is a design activity that require an extensive Design Space Exploration process (DSE), to result in cost-effective systems. The
work described here aims at defining novel methodologies for the application-driven customizations of such highly heterogeneous embedded systems. The issue is tackled at different levels, integrating different tools.
High-level event-based simulation is a widely used technique that offers speed and flexibility as main points of strength, but needs, as a preliminary input and periodically during the iteration process, calibration data that must be acquired by means of more accurate
evaluation methods. Typically, this calibration is performed using instruction-level cycleaccurate
simulators that, however, turn out to be very slow, especially when complete multiprocessor
systems must be evaluated or when the grain of the calibration is too fine, while FPGA approaches have shown to performbetter for this particular applications.
FPGA-based emulation techniques have been proposed in the recent past as an alternative solution to the software-based simulation approach, but some further steps are needed
before they can be effectively exploitedwithin architectural design space exploration. Firstly,
some kind of technology-awareness must be introduced, to enable the translation of the emulation results into a pre-estimation of a prospective ASIC implementation of the design. Moreover, when performing architectural DSE, a significant number of different candidate design points has to be evaluated and compared. In this case, if no countermeasures are taken, the advantages achievable with FPGAs, in terms of emulation speed, are counterbalanced
by the overhead introduced by the time needed to go through the physical synthesis and implementation flow.
Developed FPGA-based prototyping platform overcomes such limitations, enabling the use of FPGA-based prototyping for micro-architectural design space exploration of ASIP processors. In this approach, to increase the emulation speed-up, two different methods are proposed: the first is based on automatic instantiation of additional hardware modules, able to reconfigure at runtime the prototype, while the second leverages manipulation of application
binary code, compiled for a custom VLIW ASIP architecture, that is transformed into code executable on a different configuration. This allows to prototype a whole set of ASIP
solutions after one single FPGA implementation flow, mitigating the afore-mentioned overhead.A short overview on the tools used throughout the work will also be offered, covering basic aspects of Intel-Silicon Hive ASIP development toolchain, SESAME framework general
description, along with a review of state-of-art simulation and prototyping techniques for complex multi-processor systems. Each proposed approach will be validated through a real-world use case, confirming the validity of this solution
Studio in vitro dell'espressione di varianti del gene CFTR con ruolo patofisiologico non ancora definito
Get PDFThe mutational screening of the CFTR gene, performed with three progressive steps (screening of the most common mutations with a commercial diagnostic kit, analysis of deletions/duplications with MLPA assay and sequencing of the coding CFTR regions) leads to a detection rate of about
94%. The analysis of the CFTR transcripts, by RNA extraction from nasal epithelial cells, allows to identify new mutations and/or to define the pathogenic role of variants initially considered as polymorphisms. In this PhD study, three different mutations, identified in patients followed at the CF Center of Regione Lombardia, were characterized:
i) the c.2679 G>T mutation, initially described as a polymorphism, causes the creation of a
new donor splice site, leading to the skipping of 230 bp of exon 17 in CFTR transcript;
ii) the duplication spanning from exon 7 to exon 18, identified by MLPA assay was confirmed and characterized on CFTR transcript. This rearrangement causes a 2244-bp-out-of-frame insertion, leading to the creation of a premature stop codon located 8 amino acids after the beginning of the duplicated exon 7;
iii) the c.1584+18672 A>G deep-intronic mutation, identified in five different patients, was characterized by a combination of in-vitro (hybrid minigene constructs) and in-vivo (RTPCRs performed on nasal brushing RNA) approaches. These studies showed that this mutation creates a new donor splice site and activates two cryptic acceptor splice sites, causing the production of two CFTR transcript variants. The two alternative splicing products include a 104-bp pseudoexon and a 65-bp pseudoexon located between exon 11 and exon 12. Allele-specific measurement of wild-type and aberrant splicings from the nasal brushing RNA of the probands showed that the c.1584+18672 A>G mutation did not completely abolish the wild-type splicing in vivo. In particular, about 3,5% of the mRNA molecules produced by the c.1584+18672 A>G allele were completely wild-type; these data well correlate with the mild clinical phenotype of patients. In the second part of the PhD project, two pilot studies, aiming at the improvement of the molecular
analysis of CFTR gene, have been developed:
i) analysis of the CFTR transcript by RNA extraction from lymphocytes and lymphoblastoid cell lines, to evaluate the possibility to use a target tissue alternative to the nasal epithelium, not available in pediatric patients (age < 9 years) and in patients refusing the nasal brushing.
The data obtained, however, suggest that the very low level of CFTR expression in lymphocytes does not allow a correct analysis of transcript profiles.
ii) Development of a custom new generation sequencing (NGS) kit, using the platform HiSeq 2000 (Illumina), in order to scan the entire CFTR gene. After a careful evaluation of the
possible alternatives, we chose a target enrichment strategy and designed a set of probes covering the full-length CFTR to be used for DNA capture (custom capture kit, Nimblegen SeqCap EZ Library, Roche). The application of NGS will lead to the improvement of time and cost of molecular diagnosis, that is nowadays increasingly relevant thanks to the recent advances obtained in mutation-specific therapie
Diagnosi Energetica dell’Azienda Ospedaliera “G.Brotzu”
Get PDFHealth care facilities, particularly hospitals, are known to be among the most energy intensive. The cause lies in the large amount of energy needed to cope with the demands of medical equipment and to provide the best quality of air conditioning. Therefore, energy efficiency measures could allow achieving important economic benefits and improving environmental impact of these types of facilities.
The purpose of the research was the energy audit of the AOB (Azienda Ospedaliera Brotzu), the most important hospital in Sardinia (Italy). The work has been developed around the following topics: preliminary audit; thermal analysis via dynamic modeling; technical-economic feasibility analysis of the energy efficiency measures.
Through the preliminary energy audit we aimed to achieve a realistic description, by the point of view of the energy, of the current status of the structure. The main objective of this phase was the identification of the characteristics of the building-plant system, its use, hence the definition of the energy balance of the hospital. Much time and efforts were required to gather all the information needed to determine the current status of the structure and its systems, particularly to the collection both of historical data of energy purchase (fuel and electricity) and the survey and validation of the hourly consumption recorded by the monitoring systems already present in the structure. Following this phase, that enabled us to provide an updated and realistic view of the energy behavior of the building-plant system, we drew up the AOB’s energy balance, considering the energy flows entering the plant, the historical analysis of consumption and their economic impact. Finally, through the reconstruction of the energy flows within the hospital and the performance evaluation of the systems, it was possible to determine the energy required by the users, and their hourly loads (Heating, Cooling, Domestic Hot Water, Electricity, etc.). The preliminary energy audit was integrated with the analysis and comparison of the AOB’s benchmark indicators with those of other hospitals in the national context.
The second phase of the work involved the thermo physics analysis of the hospital via a virtual dynamic model implemented with the code TRNSYS-TRNBUILD. After the validation and the calibration of the code, we developed a virtual reproduction of the entire building that was used to perform several hourly simulations in dynamic conditions, aiming to study the thermal behavior of the structure depending on boundary conditions, such as weather, HVAC set-up, etc. With the virtual model it has been possible to achieve the following targets: verification of consumptions in compliance with applicable regulations; analysis and comparison between numerical results and data collected, with the aim of identifying the main causes of energy consumption and directing the selection of energy-saving strategies to be implemented; simulation of some energy efficiency measures by means of a numerical model more accurate and realistic of the common stationary codes.
Starting from considerations arising from the preliminary audit and the dynamic simulations, in the third and final phase of the work we analyzed some energy-saving proposals that would allow achieving important economic benefits, improving at the same time the environmental sustainability of building-plant system. Aiming to ensure a better agreement with reality, the analysis of
interventions were not carried out with numerical methods based on steady monthly calculation, but using more complex methods such as dynamic modeling (TRNSYS) or quasi-stationary codes which work on hourly loads. At first we contemplated the possibility of improving the performance of the building envelope by means of isolation of the facade, later we have examined the possible improvements by regarding the energy monitoring systems already installed in the hospital. Finally we carried out the technical and economic feasibility analysis on the possibility of using alternative systems for energy production, renewable energy technologies (solar thermal and photovoltaic), CHP (combined heat and power) and CCHP (combined cooling, heating and power) systems were examined. A multi scenario analysis was carried out to select the best technology possible in order to fulfill the energy demand of the AOB.
The methodology and tools developed during the Ph.D. are not only applicable to the case under examination (AOB). The generality and flexibility of application allows the extension in several fields of application beyond health care facilities, such as civil, commercial and industrial building
Participatory approaches in support of the decision-making processes. The ambivalence of participation
Get PDFThe dissertation concerns the analysis of participatory practices in support of the decision-making processes. In particular, the research work is based on an important
consideration, according to which, traditional participatory processes do not work in practical terms. Indeed, the evolution of the concept of participation reveals that although the implementation of the participatory processes arose from the necessity of strongly criticizing the contemporary society of the 1960’s, nowadays they have been used to reinforce and legitimate the existing power relations. In this conceptual
framework, participation is currently analysed and interpreted either as a democratic right or as an instrument to achieve specific goals. As a result, the dichotomy, between theory and practice, acquires an increasing importance within the international debate.
Moreover, the dissertation intends to interpret the intrinsic ambivalence within the concept of participation through the analysis of a case study represented by the
Sardinian Regional Landscape Plan (RLP). Sardinian regional government elaborated its RLP in 2006. However, different problems, such as the lack of implementation of the RLP at the local level, entailed the necessity for a revision. In
particular, the Sardinian case study represents an emblematic case due to the implementation of two very different participatory processes. From this perspective,
these approaches are studied in order to understand the difficulties to translate theoretical concepts about participation into practice. In addition, the research work is based on a qualitative strategy and on a case study design, where a triangulation of methods, which are traditionally related to either qualitative or quantitative research strategy, is used. In particular, the data
were collected through semi-structured interviews and self-completion questionnaires that involved different categories of participants such as academicians, officials of the regional, provincial and local governments, technicians of building enterprises, member of environmentalist bodies and practitioners. Moreover, the data analysis highlights some important considerations. First of all, the political decisions influenced negatively the outcomes of the participatory processes. Indeed, during the elaboration phase, the specific purpose of the regional
government was to legitimate its ruling role on the planning decisions at the local level, implying a lack of real involvement of participants. In the revision phase, despite the apparently good intentions, the regional government, which belongs to an opposite political alignment of the previous one, intended to represent itself as a forward-looking administration in order to increase consensus on behalf of citizens, local and provincial administrations, practitioners and the economic and productive sectors. Secondly, the lack of a solid awareness of the importance of participation makes the implementation of effective inclusive moments impossible without a methodological reference framework. From this conceptual perspective, the research work proposes a procedural
protocol, whose aim is to define a methodological framework concerning the implementation of participatory practices in support of the planning processes at the regional scale. The procedural protocol focuses on four main issues: the
interdependency of participatory and planning processes, the definition of specific responsibilities, the circularity of the processes, and their flexibility. First of all, the participatory processes should be parallel to the planning processes, becoming a necessary element of the procedures of elaboration and approval of plans. On the
other hand, despite the complementary nature of the relation between participatory and planning processes, they should not lose their decisional autonomy and independence. Secondly, with respect to the impacts of the political decisions on participatory and planning processes, the authorities that implement participatory processes should be external bodies, composed by a multidisciplinary group of
experts in political and social science, and in participatory practices. Thirdly, the circularity of the processes is based on considerations, according to which the
relations between participatory and planning processes are not linear. In this way, it could be possible to take corrective measures in the most important phases. Finally,
the fourth issue is related to specific economic, social and political contexts in which the participatory processes are implemented. Indeed, the research work tries to
maintain a certain degree of flexibility in order to make it possible that suitable adjustments of the processes in relation to the reference context do occur.In conclusion, “learning from failing” represents an important lesson of the research work. Indeed, despite the undeniable failures that characterise the current participatory practices, participation remains a significant aspect that could give adecisive contribution to the effectiveness of planning decisions