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Caratterizzazione di pannelli x-lam in pino marittimo sardo
Full text linkBackground and Purpose: The aim of this work is to present the idea of a short procurement chain of timber as a means to provide an increased value to Sardinian forests. It is based on the evidence that timber buildings are increasingly useful for a number of reasons including sustainability, the speed of erection, and excellent structural performance. However, most of the timber currently used in Sardinia is imported from outside this area. The idea is to use the best part of locally-grown trees to produce timber boards, while all the remaining part of the tree including the production waste is used as biomass for energy production. Important issues to address are the generally low mechanical properties of timber from locally-grown Sardinia trees such as Maritime Pine, which would make some wood-based products like glue-laminated timber not technically viable. Cross-laminated timber panels seems to be a possible solution to this problem because this wood-based product is manufactured in such a way that even with low-quality timber boards it is possible to obtain a medium quality panel. The panel is made of layers of timber boards with the adjacent layers glued under pressure at a right angle. Another issue is the need to grade the local timber, for which a number of specimens must be tested on destruction in order to identify a visual or a machine stress grading procedure. Last but not least, the panels must be tested on destruction to correlate their mechanical properties to the properties of the boards.
Materials and Method: the research has been developed through the following steps: 1) two maritime pine plantations with stands suitable for logging and processing were identified, extensively surveyed and sampled. On selected standing trees, based on measurements taken at different heights, the first preliminary grading was applied by sorting for structural and energy use. 2) Trees were harvested by a local company and the logs were finally assorted based on their size and their external defects. 3) The logs were then transported to the local sawmill, where different boards size required to build the grading rules and to produce the CLT panels were cut. Each board was then subjected to a non-destructive measurement of the Modulus of Elasticity using acoustic tool for measuring stress wave velocity (Viscan-Microtec) 4). After kiln drying, the required boards (approximately 840) were subjected to non-destructive measurements of their physical properties (density, humidity, defects etc.) using the machine purposely developed by Microtec. The aim was the calibration of this machine in order to enable the machine strength grading of Sardinia maritime pine. 5) The required boards were visually characterized and then tested to destruction in order to measure their strength and correlate this values to the presence of defects such as knot diameters and positions, grain deviations, etc. 6) Based on the results of phases 4 and 5, the visual and machine based grading rule for Sardinia Maritime Pine have been developed. 7) By applying the newly developed grading rules, some boards
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have been selected among the available ones and used for the production of some prototypes of CLT panels. 8) In order to determine the structural performance, 68 panel have been tested to destruction. Testing was carried out in accordance with EN 408 on specimens with a span to depth ratio equal to 18 to determine the bending strength and stiffness, and on specimens with span to depth ratio equal to 9 to determine the shear strength. A number of different methods exist for the analysis and design of CLT elements, including the Shear Analogy Method and the Mechanically Jointed Beams Theory (Gamma Method). These methods have been considered in this study and a relative comparison have been presented in order to determine which method is most suitable when considering CLT formed using Sardinian grown timber..
Results: It was found that Maritime Pine as structural material is limited by stiffness rather than strength or density. The effective bending stiffness of CLT is a measure of the material stiffness in relation to the cross sectional build-up of the panel. To be competitive on the market, a Sardinian CLT product will have to compete with imported CLT panels, which are usually made from C24 graded material (spruce). In most cases this is simply because the C24 material is widely available on the market rather than a specification from the designer. The performance of panels made of Maritime Pine boards has been compared directly with that of imported products, demonstrating that an increase in the Sardinian panel depth of just 15% is sufficient to match the stiffness of the imported panels, which is the most important design property.
Conclusions: This work lays the foundation for the development of a short procurement chain of wood in Sardinia. The EDENSO project developed in parallel to this doctorate study is still in progress and further tests on maritime pine CLT panels are planned. A short procurement chain of timber is a possible means to create job opportunities and reduce depopulation, particularly important in some area of the island. By adding value to the forests by means of timber production used in prefabricated components employed in low-rise timber buildings, it is also possible to improve forest management and even extend forested areas, which have many positive effects on the environment, the landscape and the reduction of hydrogeological hazard
Le torri costiere della Sardegna nel Mediterraneo: cronotipologie delle strutture murarie
Full text linkThe research focuses on the system of coastal towers in Sardinia, the realization of which spans more than five centuries (XIII-XVIII sec.) and reaches its peak between the sixteenth century and the first half of the seventeenth under the impulse of the Spanish monarchy. The coastal fortification process seems well documented in archival sources thanks to the establishment, starting in 1583, of the Reale Amministrazione delle torri This institution managed the system and produced a copious technical and administrative documentation. This made possible the philological dating of construction phase and historic restorations works referring to several towers.
From this awareness comes the desire to investigate, in reference to these buildings, the structural and material characteristics, with particular emphasis on building techniques with the aim of defining an abacus with chrono-typological value. The choice of subject was also influenced by the awareness of the absence of studies, referring to Sardinia, oriented to the knowledge, documentation and chronological definition of construction praxis adopted for the construction of the masonry structures. So, with the awareness of the influence that Spain exercises in the definition of the architectural types and construction techniques in the countries that were under his dominion (direct or indirect), the ongoing study opened to the comparison between Sardinia and other Mediterranean contexts.
Considering the high number of buildings investigated, the study was structured in homogeneous districts also taking care to safeguard all-embracing perspective that takes into account the specificity of the system. Starting from a systematic investigation in situ, eight representative cases-study were identified, selected from the towers belonging to a precise chronological range (16th-17th centuries). Specifically, the study focused on the following towers: Porto Giunco (Villasimius-Sarrabus Area), Mezza Spiaggia (Cagliari Area), San Macario (Teulada-Chia Area), Capo San Marco (Oristano Area), Ischia Ruggia (Bosa Area), Airadu (Alghero Area ), Trabuccato (Stintino-Asinara Area ) and Isola Rossa (Gallura Area).
The need to ensure a systemic approach to the subject, and then to detect a large number of buildings, determined the decision to integrate the classic relief tools with innovative survey methodologies, based on photogrammetric techniques. This made it possible to acquire, in a short time, a satisfactory number of data related to the volumetric characteristics of the investigated buildings, allowing you to check and sometimes refute the previous typological classifications. At the same time, the processing of the product derived from "photomodeling" process provided a detailed basis on which to conduct analytical studies.
With the objective to evaluate the many aspects of the subject, a multidisciplinary and integrated protocol was adopted: the towers were studied from a historical point of view, architectural and typological, technical and mineral-petrographic favoring a stratigraphic approach tailored to the peculiarities of the topic. Cataloging, georeferencing and insertion into a geographic information system made it possible to establish a multi-layer dynamic comparison and thus to reach a critical synthesis of the results obtained.
This methodological approach has led to interesting results and represents a small advancement in the knowledge of these artifacts. In general, while taking into account the number of persons who commissioned the construction, all the towers analyzed shared the choice of a type of easy to build, with technical and architectural solutions far from modernity that characterized other similar systems. The adoption of these solutions, however, meets the basic military requirements. It is strongly influenced by the scarcity of population and economic resources and the need for shorter construction times. Indeed, a low population density in the island coasts and the constant shortage of financial resources, always aggravated by lack of interest by the central government, justified the adoption of a particularly expensive model.
Similarly, in the realization of masonry structures, the short construction times and lower construction costs represent common imperatives. These aspects have influenced the quality of the mortar, often not optimal, and the choice of the stone material. Also the masonry technique most commonly adopted, a cantieri, was an expression of the same needs. It used the most of the available materials, responding to structural requirements. The systematization of the dimensional data relating to the cantieri revealed the recurrence of certain values such as to identify invariants of great interest for the chronological definition of masonry structures. The texture appears almost always irregular, with extreme heterogeneity in dimensions and morfhology of the stone elements. It was conditioned, as expected, by the level of workability of the material.
The data obtained in the analytical phase converge in the project guidelines, aimed at providing methodological ideas and cultural references useful for restoration works. In addition, the multidisciplinary approach, supported by the integration of technological and innovative technical tools, reveals a spendable methodology in other contexts, and to a larger scale. Finally, the typological classification of a wide repertoire of masonry techniques, referred to a specific chronology can be an important basis of comparison for the dating of contemporary buildings
Three Essays on the generalizability of experimental results in economics
Full text linkAlthough few economists today dismiss the use of the laboratory experiments, it would be a mistake to think that experimental methodology no longer represents a controversial issue in economics. One of the major criticisms is represented by the external validity of experimental data and concerns the transferability of results obtained in laboratory to the real world. The aim of this thesis is to tackle the issue of external validity focusing in particular on one aspect: the possible lack of representativeness of standard subjects pools usually used in economic research. The first experimental study compares the choices of undergraduates and subjects representative of population in different treatments and with different reward dimensions by exploiting the experimental design used by Pelligra and Stanca (2013) to investigate social preferences in a field experiment. Our results show that two samples follow a common behavioral pattern with the only exception of a significant difference in choices where self-interest may play a prominent role. In the second study we use a between-subjects design to compare the behavior of experienced and inexperienced subjects. We investigate whether the laboratory experience, built through repeated participation in experimental sessions, biases subjects’ behavior in a set of representative simple games used to study social preferences. Our main finding shows how subjects having a high level of experience in lab experiments do not behave in a significantly different way from novices
La qualificazione degli interessi plurisoggettivi e l’evoluzione dei mezzi di tutela nel sistema amministrativo
Full text linkSubjective legal positions are legally irrelevant firstly, because they have
superindividual features and they do not refer to a specif subject.
There are many legal scholars who have qualified the interests such as interests of a
purely factual and they have started the discussion of legal consistency of common
interests and arrangements of protection.
Many docrtinal conflicts about protections way of collective interests started due to the
conflicting between collective nature of the interests and personal nature of common
interests.
The problem of relevance has been overcame through the attribution of legal standing to
exponential authorities, bearers of collective interests, then it has gone in search of the
ways of protection both in procedural and in the judicial.
Collective action that finds its most typical expression in the US class action has also
been welcomed in our system and also with regard to public administration, aimed at
overcoming the inefficiencies and reduce bureaucracy delays, with a view 'transparent
administration and higher quality.
In conclusion the discussion can be said dormant, because the common interest have
been overcame instead the assimilation of the candidate positions is increasing, relied
by collective bodies to individual rights
La funzione di comunicazione delle pubbliche amministrazioni tra dinamiche di apertura ed esigenze di partecipazione
Full text linkThis research wants to follow the elements that characterize the administrative function
inside the public communications activities, and to highlight the distintive aspects,
considering the changes that involved the public administration within the current
process of open government.
Preliminary to reconstruction is the study of the concept of “function”, examined in
deph by public law doctrine.
After this introduction, emerges that public function’s communication is already
consolidated because is largely recognized by doctrine, noticing the presence of some
elements: global interest in public information, connected to the right of citizens to be
informed, juridical importance, related to the right and obligation to know, and the
presence of legislation; the organisation in specific offices.
From the doctrine debate emerged some opinions that qualified the public
communication as a special system, for the difficulty to be objective.
Thi aspect influenced the rule of communication in the realization a democratic system
to guarantee openess to public institution and participation of citizens, and concern
relation between communication and power.
This issue originated from evanescent border between institutional communication and
politics communication, that is connected to the risk of becoming propaganda that
compromise the impartiality of public function. In its origin lives the distinction of its
informational process to promote image of administration and who rules it, and of
communication process that realize a citizen’s dialogue.
This aspect gets more importance considering the expansion of public function, that
today is an essential factor in the administrative action, based on transparency,
openess, and participation.
Here’s a thought on the necessity to combine this metamorphosis, with a revision of
legislation, starting from law n. 150/2000, and digitisation process.
This riform will consider transformation inside connection between public
administration and citizens, and priority necessity to guarantee objectivity and
impartiality to communication’s activities. All of this to ensure the respect of the
general interest of knowledge
Conception, design and evaluation of an ICT platform for independent living and remote health monitoring
Full text linkThe current society is dealing with a progressive ageing of the population. Life expectancy
is constantly increasing and, at the same time, families tend to have less children than in
the past. For these reasons, the global proportion of people aged 60 or over is expected to
outnumber the younger age groups. This trend will have a serious impact on the society,
since the health related costs will rise, there will be a lack of professional caregivers trained
to assist the elderly and more and more people will suffer from chronic diseases that must
be treated somehow. To overcome this situation, in the past years many initiatives aiming
at increasing the elderly independence were born. The problemin developing technological
systems for the elderly is that they are reluctant to try out newsystems and devices, so a great
emphasismust be put on the design of an acceptable and usable solution. In this thesis, an
ICT platform for independent living of older adults is presented. The platform is based on
a standard TV and remote control, in order to lower the risk of technology refusal by older
people, and aims at offering a rich set of services that include social networking, support,
welfare and health. The health aspect is important but not the leading one, since such platformshould
be first perceived as useful for different aspects of their daily life, and not strictly
related to the concept the being oldmeans having health problems. Another aimof the proposed
platformis to expand the offered services by involving external service providers, that
will exploit the basic functionalities offered natively by the platform. The aspects related
to the initial studies that let to the definition of system requirements and technical specifications
will be presented, together with some preliminary usability results obtained from
several user tests. Starting from mid 2016, the proposed platformwill be tested during three
field trials in Italy, Belgiumand the Netherlands
Caratterizzazione geo-petrografica, petrologica e geochimica di rocce anatettiche del nord Sardegna
No full textThe High Grade Metamorphic Complex (HGMC) of Variscan basement of north Sardinia is characterized by the widespread of migmatites. This study is focused on two localities of NE Sardinia (Porto Ottiolu and Punta Sirenella) where ortho- and para-derivates migmatites outcrop. A geological and structural survey was carried out, leading to the realization of a geological schematic map of Punta Sirenella area. Several samples of different rocks were collected for petrographic, micro-structural minero-chemical and geochemical analyses.
In the Porto Ottiolu area three main deformation phases have been identified; D1, characterized by tight folds with sub-horizontal axes, rarely preserved in paragneisses; D2, that produce a pervasive foliation oriented N100° 45°SW marked by biotite and sillimanite blastesis and locally transposed by shear zone oriented N170°; D3, late deformation phase caused symmetric folds with sub-horizontal axes with no axial plane schistosity. Leucosomes form pods and layers along S2 schistosity but also leucosomes along shear zones have been observed. In the Punta Sirenella area, three main deformation phases have been identified; D1, is manifested by the transposition of centimeter-sized leucosomes and is rarely observed in paragneisses were produce open folds with sub-vertical axes; D2, NW-SE oriented on whose XY plane three mineralogical lineation (quartz+plagioclase, fibrolite+quarz and muscovite) lie; D3, a ductile-brittle deformation phase that produce a mylonitc S3 foliation that locally become the most evident schistosity in the field oriented N140° steeply dipping toward NE.
In both areas, leucosomes of sedimentary-derived migmatites are generally trondhjemitic pointing out for a H2O fluxed melting reaction, but also granitic leucosomes have been found, produced by muscovite dehydration melting. Leucosomes of migmatitic orthogneiss instead, have granitic compositions. Migmatization started early, during the compressional and crustal thickening (sin-D1, pre-D2) and was still active during exhumation stage.
For each studied outcrop of migmatite pseudosections for the average mesosome composition have been calculated; these pseudosections have been used to model the P-T conditions of anatexis on the basis of the melt volume (%) of melt, Si/Al and Na/K molar ratios, modal content of garnet and Si content in metamorphic white mica. Further pseudosections have been calculated for the average composition of leucosomes in order to define the P-T conditions of the end of the crystallization through intersection of solidus curve and isopleths of Si content in white mica and/or XMg ratio in biotite. Thermodynamic modeling on ortho- and sedimentary-derived migmatites of Punta Sirenella yield P-T conditions of 1.1-1.3 GPa - 670-740°C for migmatitic event and 0.75-0.90 GPa - 660-730°C for the end of crystallization. These conditions are fit well with previous studies on adjacent rocks. Modeling of Porto Ottiolu ortho- and sedimentary-derived migmatites yield P-T conditions of 0.85-1.05 GPa - 690-730°C for migmatitic event and 0.35-0.55 GPa - 630-690°C strongly affected by re-equilibration during exhumation, expecially for crystallization conditions.
Geochemical analyses of samples belonging to Porto Ottiolu and Punta Sirenella orthogneisses show a strong link with those of other orthogneisses outcropping in NE Sardinia (for instance, Lode-Mamone and Golfo Aranci) that are considered the intrusive counterparts of middle-Ordovician metavolcanics rocks outcropping in the Nappe Zone. Thus, the studied ortogneiss bodies, even lacking radiometric data, can be considered as belonging to the same magmatic
cycle
Solid acid catalysts for biorefinery processes
Full text linkThe present work regards the study of alternative synthetic routes for biofuels and biochemicals. Biofuels and biochemicals constitute the two main classes of biorefinery products. Biofuels are obtained from biomass and have many environmental advantages over the traditional fuels. In this work particular attention has been given to biodiesel, one of the most widely used biofuels. Biodiesel is a safe, non-toxic, and biodegradable alternative diesel fuel. The development of active acid catalysts for biodiesel synthesis could reduce the production costs, in particular because the acid catalysts permit the use of low value feedstocks such as waste and non-edible oils. Biodiesel production occurs with co-production of glycerol, which is co-product also in other industrial productions such as the production of fatty acids and soaps. Because of its large production the market demand is largely less than the supply. For this reason glycerol is considered a problematic product. Possible solution to its disposal is the use as platform chemical in the production of high value bioproducts. Among them are particularly interesting the trioses dihydroxyacetone and glyceraldehyde. They could be feedstocks for an alternative synthetic way for lactic acid and its esters. Lactic acid and lactates are, nowadays, considerably important because they are used as building blocks in the production of biodegradable polymers (the polylactic acids), which are potential substitute for petroleum derived polymers. Lactic acid is also one of the most promising bio-based platform molecules. The high costs of the conventional production process hinder the use of lactic acid and lactates in many applications. So it is essential to develop cheaper and greener synthetic routes.
In this work catalysts synthesis, characterization of the materials, and catalytic testing have been carried out mainly at the Laboratory of Industrial Chemistry in the Department of Chemical and Geological Sciences of the University of Cagliari.
The study involved the use of several techniques for the characterization of the materials. All the catalytic results have been related to the acid properties of the tested materials. For this reason the measurements of adsorption microcalorimetry and adsorption FTIR using basic probe molecules have been the most important used techniques in this work.
The measurements of adsorption microcalorimetry were carried out at the Laboratory of Industrial Chemistry in Cagliari while the measurements of adsorption FTIR were carried out under the supervision of Prof. Konstantin Hadjiivanov at the Institute of General and Inorganic Chemistry of the Bulgarian Academy of Sciences.
This work is divided in five chapters. The first chapter is an introduction of the fundamentals of sustainable chemistry, biorefinery and acid-base heterogeneous catalysis. The
second chapter is a description of the most important techniques for the characterization of acid-base properties of solid materials. In the third chapter are listed the used materials, the experimental procedures and apparatus. The chapter four is the study of the acid catalyzed transesterification of tryglicerides for the production of biodiesel and glycerol. In chapter five is described the work on the conversion of dihydroxyacetone to methyl lactat
Margaret Thatcher. Formazione e ascesa di un leader.
No full textThe thesis sets out to examine the character of British politician Margaret Thatcher, following the path of her life and her career since her years at the University of Oxford, where she studied chemistry, to her election as the leader of the Conservative Party in 1975. The investigation has been conducted by examining a number of sources and documents: minutes of meetings, electoral speeches and manifestos, accounts of informal exchanges, transcripts of parliamentary debates, articles and editorials published in both local and national newspapers. The aim of the research, on the one hand, is that of filling a gap in the Italian scholarly literature on the subject, while, on the other hand, bringing to light a number of underestimated factors, which have in time contributed to turning the “Grantham girl” into a world leader. The investigation covers three decades during which Thatcher has evolved from “the grocer’s daughter” into “the iron lady”. The originality of the research consists in its attempt to show to what extent the main traits of what will get to be known as Thatcherism started to emerge well before Thatcher’s election to the role of prime minister and, therefore, how the political climax of her story had already reached its peak in 1975. By examining the crucial events which marked Thatcher personal and political history the thesis aims at providing a picture of British society during the period under scrutiny as well as at unveiling a degree of complexity, in both Thatcher and British society, which has often been under investigated
Urbanistica informale degli slum nelle città metropolitane. Processi migratori e modelli significativi delle forme di inurbamento. Interventi sperimentali negli slum di Mumbai
Full text linkThe phenomenon of slum with its related problems interests different regions in the world and it is one of the most interesting topics for the multidisciplinary research, in particular on issues of urban migration in large cities. For various reasons, it is difficult that this phenomenon could be formalized by the planning tools.
The main aim of this dissertation is to analyse, interpret, evaluate the different social and economic factors of informal settlements that characterize the growth in the metropolitan areas of many countries. On this basis, the research compares the different urban and suburban informal settlements that have not yet acquired and certified.
The thesis is divided into two parts. The first deals with a survey of the slum settlements in some countries strongly characterized by the phenomenon of slum: Mexico, Argentine and Brazil in Latin America; Kenya in Africa and India in Asia.
In order to analyze this phenomenon, and its broader aspects, the thesis focuses on the dynamic not only of the migration flow, from Europe to America, but also of wars, conflict and persecution which are causes of illegal immigration, that, particularly in Africa, are a very topical issue.
The second part of the thesis treats Dharavi and Shivaji Nagar slums in Mumbai (India). They are the most important examples of informal settlements in Asia because of different levels of aggregation, and also because urban and social literature recognises them as the most difficult problems for size and complexity.
Mumbai was the city where the empirical research took place. The collaboration with Indian architects allowed to describe experiences and cases study that helped to understand models of aggregation and sustainability of the slums considering political activities and projects produced by the Municipality of Mumbai.
Stakeholders interviews, characterised by different age and gender, made possible to understand and represent different housing and land reclamation of slums.
This research underlines the difficulties that cities will have as increasing of the land use due to non programmed migration flows. Therefore, urban planning, interested on the periphery, the enclave of poverty and social distress within the city, needs to choose which kinds of urban design tools could adopt. In fact, zoning, as land-use planning tool, needs to face with these new realities so as to suggest solutions for redevelopment of informal settlements especially where it is important to consider the socially and economically consolidated contests