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Cristallizzazione del solfato di sodio in calcari biomicritici: l'uso di inibitori per la mitigazione del degrado
No full textSalt crystallisation is one of the most harmful decay problems in porous materials. Especially ancient building and archaeological sites can show very intense damage (e.g. detachment and pulverization of the materials) that produce a strong loss of matter and so cultural identity. Mainly hypogea show salt crystallisation due to capillary rising. However also anthropic sources like pollution or cement can be found in these sites producing decay. Sodium sulphate is very common where there is the combination between cement and pollution. This salt is very harmful for porous materials due to his high crystallization pressure and the possibility to change to anhydrous phase to hydrated one. When microclimatic variations occur due to semi-confined environment, phase transitions of sodium sulphate take place with consequence on porous material decay.
This research studied sodium sulphate crystallisation on a Mediterranean biomicritic limestone and the action of crystallisation inhibitors to mitigate it.
The early Christian burial of Munazio Ireneo was studied to understand sodium sulphate crystallisation in biomicritic limestone. Diagnostic investigation and microclimatic monitoring were carried out to understand decay phenomena. The hypogeum is a semi-confined environment and high damage can be found due to phase transition of sodium sulphate.
Crystallisation of a Mediterranean biomicric limestone was also studied in laboratory by XRD, OM, SEM, MIP and NMR analysis. Crystallisation inhibitors were tested on the limestone in sodium sulphate solution capillary rising. Two different inhibitors were applied with two distinct system (immersion and poultice). XRD, MIP and SEM analysis were carried out to understand the modification of the inhibitor on the stone microstructure. The loss of material was evaluated to understand the effect of the inhibitors comparing the loss of material in the blank sample. A greater loss of material than the blank sample was found when the first inhibitor was applied through both of the system; the second inhibitor had a minor loss of material but chromatic variations could be found on the stone
Las milicias en el Mediterráneo occidental. Valencia y Cerdeña en la época de los Austrias
Full text linkIn evolutionary terms, it is generally accepted that in the early decades of the sixteenth
century the art and scale of war changed. The increase of the professional component in royal
armies caused logistical and economic difficulties to solve by the royal administration. With a great
empire to defend, the Hispanic Monarchy focused on their military resources to the most strategic
borders.
For this and other reasons, traditional forms of military organizations, suchs as local militias,
were far from being former things: defending the cities, towns and villages of the kingdom was the
responsability and the right of the neighbours. This is the subject of our reseach and focusing on
kingdoms of Valencia and Sardinia during the sixteenth and seventeenth centuries.
According to the documentation found, in both kingdoms traditional forms of military
contribution were revised with a different operational scale and service conditions after the fall of
La Goleta in 1574. About this reality shared at the end of sixteenth century, our main objective is to
make a comparative study between the two forms of territorial militia
Cinquant'anni di padri della patria 1848-1900
No full textOne of main examples of the organization of political consent and of the building of nation-wide feeling can be found in Italy during the second part of 19th century.
In the recent years, historical studies have been increasingly oriented in investigating how the events and the figures of the period known as “Risorgimento” have been re-interpreted in the subsequent years in a mythical and celebrative way to support and legitimate the political choices of specific groups. Nonetheless, so far none of these studies have analyzed how was created an interest among the wide public around the protagonists of the political events of Italian “Risorgimento”. In this context, the present study investigates how key figures as Giuseppe Mazzini, Vittorio Emanuele II, Giuseppe Garibaldi and Camillo Benso di Cavour were seen by the public opinion in the second half of 19th century and how the re-interpretations of the events that had led to the reunification of Italy were used to create the myth of the “Fathers of the Nation”.
The analysis concerns the period between 1848 and 1900 and has been divided in three sections: the first (1848-1861) concerns the events that led to the reunification of Italy when those who would became the Fathers of the Nation were still interacting each other some time in a conflicting manner. The second section consider the period 1861-1976 when the antagonism between these figures was changing to memory. The last section deals with the period between 1875 and 1900 in which the left-wing governments promoted a re-interpretation of the events of “Risorgimento” in a way that mitigated the contrasts and strengthen the public consent around those who were seen as founders of the nations
Experimental and numerical investigations to assess the behaviour of a buried pipeline in areas with high geological instability
Full text linkGround displacements such as landslides, fault movements, soil liquefaction which may be
caused by seismic activity are one of the most dangerous phenomena that can involve buried
pipelines, e.g. for oil and gas transportation, or water and sewage. This aspect is currently
an important part of research and a challenge for lifelines owners that are interested
in prevent or limit pipeline damages.
Within the framework of GIPIPE1 research program (SAFETY OF BURIED STEEL
PIPELINES UNDER GROUND-INDUCED DEFORMATIONS) new full-scale facilities
have been developed and adopted in order to investigate pipe-soil interaction mechanism
(in particular sand and 8” 5/8 X65 steel pipes). The new experimental facilities have been
designed to perform two groups of tests: simple interaction tests (axial pullout and transversal
pullout test) and complex interaction tests (reproducing a pipeline crossing landslide).
A system of steel containers (stationary and fixed) in which pipe samples are buried
within the sand, have been assembled. Numerical analyses have been performed using
strength parameters of sand and steel obtained from laboratory testing and subsequently
validated by means full-scale experimental results.
The outcomes of the experimental activity showed some differences in soil reaction on
pipe by increasing the relative density of soil filling and using a smoother coating.
Moreover peak soil resistances estimated with equations suggested by ASCE guidelines [4]
cannot predict satisfactory measured axial and lateral soil reactions. This is a confirmation
of previous studies in which was evidenced the effect of soil dilation in the annular soil
zone around the pipe during axial relative movement between pipe and soil causes an increase
of the normal stress at pipe soil interface, in particular the horizontal direction is
significantly constrained by the surrounding soil mass leading to an higher increase in lateral
soil stress in this direction respect to the vertical direction. Therefore this phenomenon
leads to a lateral earth pressure coefficient K which is greater than K0 (coefficient of pressure
at rest) as suggested in the ASCE guidelines [4], therefore for a better estimation of
soil response using that equation it is suggested to measure the ratio between horizontal
stress and the vertical stress during a full-scale axial pullout test.
Pipes submitted to lateral soil displacement with a constrained uplifting show as expected a
greater soil reaction than that estimated by ASCE [4] and PRCI [20].
As far as the landslide/fault test are concerned, the maximum soil relative density (Dr)
achieved during experimental tests performed in this study was around 40%. This level of
density led to a low stiffness of soil mass hence a limited global deformation of a 24 m
embedded pipe during landslide/fault tests in which one caisson was moved up to 4 m respect
to the initial position. These experimental findings confirm that sand with a low value
of maximum achievable density may prevent from high loads developing on pipelines,
in contrast to native soil which can apply higher loads.
Numerical analyses and their validation gave us a suitable instrument to estimate the pipe
soil response for large ground displacements phenomena
Evoluzione naturale ed impatto antropico sui sistemi costieri della Penisola del Sinis (Sardegna centro occidentale)
Full text linkAll over the world the coastal strip has suffered over the centuries the presence and the activities of
the human beings: the historical needs of defending the countries from the invasions and to exploit
natural resources for subsistence, have caused significant impacts on coastal environments, which
now shows environmental changes hardly reversible. The Sardinia region despite having been
affected more late from the effects of a fast economical and territorial development, shows
noticeable mutations of the coastal strip, especially functional to a recreational and tourism use of
the beaches and surrounding areas.
The Sinis Peninsula, located along the central-western part of this region, despite having been
historically characterized by a constant and important human presence (well represented in
particular by the remains of the Nuragic native culture, but also of the Roman, Phoenician-Punic
and Arabian), is often considered as one of the parts of Sardinia that has been only partially affected
by modern human impacts.
The need to understand how the presence and human activities may have worked on the present
stage of the evolution of the coastal environments in the Sinis Peninsula, led to the development of
the proposed research theme, whose main objective has been achieved through the integration of
several research methods and themes. To achieve this result six representative Sinis Peninsula beach
areas were studied through field laboratory and research activities. The first, primarily through a
series of geomorphological, sedimentological and multi gave reliefs have allowed to determine the
current status of the environments in study, both for the natural characteristics both for their direct
interaction with the human activities. The latter mainly by means of historical photo interpretation,
has allowed to assess the main changes that have occurred in the Sinis Peninsula in a specific time
span, conceptually defined in this study as a period denominated Antropogene. The activities have
been completed trough some corollary activities, which consist in the exam of some historical
photographic documents, in the development of a expeditious geomorphological survey method and
in the analysis of a particular environmental situation that occurred in one of the beaches in study.
A final proposal for the development of an environmental index has permitted to achieve a
satisfactory final result
Ossitocina nella Sostanza Nera del ratto: azione sull'attività locomotoria e interazione con i neuroni dopaminergici, glutammatergici e GABAergici nigrali
Full text linkOxytocin, the neurohypophyseal hormone well-known for its hormonal role in lactation and parturition, also exerts a wide range of effects acting in the Central Nervous System as a neuromodulator or neurotransmitter. An increasing number of experimental studies have suggested that, in rodents, central oxytocin exerts also a modulatory role on locomotor activity, but little is known about the cerebral areas in which oxytocin might act to produce this effect.
The substantia nigra, a mesencephalic structure which is part of the basal ganglia, a group of interconnected nuclei involved in motor and non-motor functions, receives oxytocinergic projections from the parvocellular compartment of the paraventricular nucleus of the hypothalamus. Moreover, oxytocinergic receptors and oxytocin receptor messenger RNA have been shown to be present in human and rat substantia nigra, respectively. Furthermore, it has been demonstrated that a significant decrease in the number of oxytocin-immunoreactive neurons occurs in the paraventricular nucleus of patients suffering from Parkinson’s Disease, a progressive neurodegenerative movement disorder characterised by the degeneration of the cell bodies of nigrostriatal dopaminergic neurons projecting to the dorsal striatum.
In order to investigate the role of nigral oxytocin in locomotor activity, a combined approach comprehensive of immunohistochemical, behavioural and lesion studies, has been used in male rats. First, the effect on locomotor activity of low and high doses of oxytocin, given intraperitoneally or into the substantia nigra, and of d(CH2)5Tyr(Me)2-Orn8-vasotocin, a selective oxytocin receptor antagonist, given into the lateral ventricles or into the substantia nigra, were studied in male rats habituated to the experimental conditions in order to avoid novelty-induced behavioural effects. Second, the presence of nigral oxytocinergic fibres and their localization with respect to nigral neurons immunoreactive for tyrosine hydroxylase (TH) (a marker of dopaminergic neurons) was investigated by immunohistochemistry. Finally, the effect on spontaneous locomotor activity of the bilateral injection into the substantia nigra of oxytocin-saporin (OXY-SAP), a recently discovered neurotoxin that specifically destroys neurons presenting oxytocinergic receptors on their surface, was studied in relation to the modifications induced in the dopaminergic, glutamatergic and GABAergic systems, assessed by immunohistochemistry using antibodies against TH, vesicular glutamate transporters (VGluT1, VGluT2 and VGluT3) and glutamate decarboxylase (GAD). Together, the results of the above experiments with oxytocin and d(CH2)5Tyr(Me)2-Orn8-vasotocin and those with OXY-SAP, which revealed the existence of a correlation between the changes in locomotor activity found in OXY-SAP-treated rats and the extent of the changes in nigral TH, VGluT1, VGluT2 and VGluT3 immunoreactivities measured at 28 days after OXY-SAP injection, provide support for a modulatory role of oxytocin on locomotor activity at the level of the substantia nigra
Il pensiero algebrico:questioni di natura epistemologica e didattica
Full text linkThe subject of this thesis is the study of the birth of algebraic thinking, as a generalization
process, in 10 to 14 years old pupils.
We analyse the relationships between the ways of describing a general algorithm, the strategies
applied in solving arithmetical-algebraic problems and verbal and symbolic languages.
As a result of the study, we can confirm that the causes of some difficulties in learning
elementary algebra are due to a didactic obstacle rather than to an ontogenic obstacle.
Furthermore, we have found some features of didactical activity in classroom that can further
or prevent generalization processes
Metal complexes with biological activity
No full textCancer is a group a diseases that involves abnormal cell growth with potential to invade or spread to other parts of the body, and it represents the second leading cause of death in developed countries.
Cisplatin is one of the most chemotherapeutic drug. In spite of its great efficacy, it shows several side effects and most patients develop a resistance to cisplatin. To overcome the cisplatin resistance, drugs are often administered in combination in order to exploit the drug synergy. After discovery of cisplatin, the research focused on metal complexes less toxic, more effective and that exploit synergistic effect when used in combination.
In this work I studied new copper, zinc and vanadium complexes with biological activity. I tested in vitro the studied compounds alone and in combination with drug currently in use against a panel of wild type tumour cell lines and their cisplatin-resistant sublines. I applied chemometric tools such as experimental design (ED) and artificial neural networks (ANNs) to the biochemical data collected. Finally, I used the artificial neural networks to evaluate the cell culture cross-contamination.
I selected a new family of copper(II) complexes with 1,10-phenanthroline (phen), 1,10-phenanthrolin-5,6-dione (phendione), and 1,10-phenanthrolin-5,6-diol (phendiol) for the synthesis of new antiproliferative agents. Considering that the DNA is an important target for several cytotoxic metal complexes, I studied the interaction of these Cu(II) complexes with DNA. I tested the ligands and complexes against normal and tumour derived human cell lines.
I tested combinations of the studied complexes and cisplatin for their potential synergistic effect against a panel of wild type tumour cell lines and their cisplatin-resistant sublines. I evaluated the selectivity of drug combinations testing the compounds also against ex vivo cultures of human normal cell lines. Considering that the synergy may arise from a chemical reaction among the
drugs, I studied the possible formation of new adducts between cisplatin, copper(II) complexes and glutathione.
I studied the phospholipid profile of wild type human cancer cell lines and their cisplatin-resistant sublines, given that changes in lipid composition and distribution on the cell membranes have been observed in cancer cells.
The in vitro cultured cell lines are widely used as model in biomedical research and the cross-contamination of cell lines represents a highly relevant problem. The ex-post discovery of erroneous results and conclusions led to paper retraction and many high-impact journals started to adopt a zero-tolerance policy requiring confirmation of cell line identity as prerequisite for publication. On the base of these considerations, I decided to develop and validate a method for evaluation of cell culture cross-contamination.
I also studied zinc and vanadium complexes. Zinc is an essential metal ion involved in a wide variety of biological processes and several proteins bind zinc for their proper functioning. I studied zinc complexes with the drug methimazole (MeImHS) and its anion (MeImS) in order to provide information for the structure prediction and reactivity of Zn-metalloproteins and -metalloenzymes.
Vanadium plays a number of roles in biological systems and vanadocene dichloride was the first discovered vanadium species with antitumour activity. Considering that the mechanism of the anticancer agent vanadocene dichloride is closely related to the biotransformation in the blood plasma, I studied the speciation of vanadocene dichloride in the plasma under physiological conditions.
In order to prepare new metal complexes, I also synthesized and characterized a new group of Schiff base ligands derived from salicyladehyde and six natural amino acids.
For the analysis of the collected data, I used the ED to set up the experiments for the evaluation of the synergistic effect of drug combinations, and for the study of the possible formation of new adducts between cisplatin, glutathione and studied complexes. I used ANNs for predict and quantify the synergism of drugs, and for the evaluation of cell culture cross-contamination levels
Modelling, design and analysis of innovative thermal energy storage systems using PCM for industrial processes, heat and power generation
Full text linkThe topic of this PhD thesis is framed on the study and the analysis of thermal energy storage (TES) systems based on phase change materials (PCM) to be used as a back-up for intermediate temperature applications (up to 250 °C). The work is divided in two part: the first part presents the development of numerical models of the latent heat thermal energy storage (LHTES) devices. Different models are developed by means of a 2D and 3D numerical simulation codes specifically implemented in the COMSOL Multiphysics environment. Design of LHTES requires knowledge of the heat transfer process within them, as well as the phase change behaviour of the PCM used. For simulate the PCM, two approaches are used: the first approach takes only into account heat transfer by conduction during the entire process, also when the PCM is in the liquid phase. In the second, the energy equation considering both heat conduction and natural convection is solved to predict the behaviour of the PCM. Different PCM materials, geometries and configurations of the storage device are considered and tested in order to evaluate the effectiveness of the adopted numerical codes under different working conditions. Finally, the models are validated using experimental data obtained from tests carried out on a double tube heat exchanger with fins and with Rubitherm® RT35 paraffin as PCM. The tests are conducted in the laboratories of the University of Lleida (Spain) by the research group GREA Innovació Concurrent.
The second part of this work concerns the design and implementation of a test rig, specifically built for experimental investigation of heat storage devices in the laboratory for TES technologies of the University of Cagliari. An accurate study and selection of both the test rig layout and all the needed equipment is carried out to perform experimental analysis.
The test bench is composed of an electrical heater, which heats the HTF up to the operating temperature, an air cooler, which simulate the thermal demand during the discharge phase, a HTF circulating pump, two test sections for thermal energy storage systems, and a preliminary TES device which consists in a shell and tube heat exchanger, where the HTF flows in the tubes while the PCM is placed in the shell side. At this stage, the thermal energy storage system, the measuring devices and the data acquisition system are under implementation
Trattamento di Biomasse vegetali e algali finalizzato all'ottenimento di energia. Potenziali sviluppi in Sardegna
Full text linkThe biomass employ for energy purposes is the subject of debate and controversy, especially as regards the use of plant species of interest to food and agricultural land. Indeed, the cultivation of plant species for energy enables diversification of agricultural activities, the recovery of wild areas or the exploitation of land not suitable to food production, but requires the use of resources and energy, which must then assess the environmental impacts.
The use of biomass in the energy production is a complex issue that involves many aspects such as the knowledge of the actual extractability in a given territory, the chemical and physical properties, the availability of efficient technologies for energy conversion and last, but not least, the management of the supply chain. This aspect is very important when using residual biomass.
This doctoral thesis has been carried out to evaluate the biomass energy production in Sardinia, considering the availability and the distribution of these resources in the region, the economic and environmental context. Specifically, it has been taken into account the potential of plant, residual and algal biomass.
In this work are examined the main technologies used for biomass energy conversion, with a special reference to thermochemical and biochemical processes. In the thermochemical, combustion, gasification, pyrolysis, pyro gasification, hydrogen production are described. In the biochemical, anaerobic digestion and energy production from microalgae are illustrated. The biorefinery concept is highlighted and the major hurdles to the production of energy from biomass are considered.
The amount and distribution of biomass in the whole region in terms of dedicated crops, both agricultural residues and agro-industrial are subjected to a detailed analysis. It is also evaluated the potential energy of each resource and the thermochemical and biochemical energy conversion technologies are identified as the most practicable with a high degree of effectiveness in Sardinia.
Regional planning of the biomass energy production requires the exact calculation of the energy needs, the mapping of all the resources available and finally, the definition and implementation of specific strategies.
The Biomass Regional Plan is viewed in the overall Regional Action Plan for Renewable Energy and the detailed strategy for this sector is illustrated. Particular emphasis has been given to the segment of the residual biomass because these represent available low cost raw materials for energy production, but are also very important from an environmental point of view.
The results of many tests carried out on a pilot plant for anaerobic digestion, are showed in detail. Several tests were carried out by the treatment of the residue of the vegetable market of Sardinia, the waste of the processing of potatoes and the by-products of the oil and dairy industry in the co-digestion with energy crops.
To identify the specific relations between the most significant variables for the process, even when subjected to a wide range of variation, the multivariate statistical analysis was employed.
The forest biomass have a wide use in the thermal energy production in large areas of the planet. The largest share of biomass fuel comes from the woods and is represented from the direct combustion of the trees or the forestry residues. The construction of a forest biomass-energy chain, however, must take into account many technical, economic and environmental aspects.
A study in Ogliastra, for the assessment of availability and distribution of forest biomass, targeted planning of a specific energy supply chain is presented. The study required a methodology of recognition and assessment of forest resources based on GIS method with the use of soil paper integrated with the vegetation chart. The forest biomass have been subjected to a chemical-physical analysis for the evaluation of the energy potential of the territory. The choice of the best energy conversion technology was performed by applying a multi attribute method (MADM).
The ability of algal biomass to grow rapidly and to store high amounts of oil has long been known and a lot of studies have been undertaken to make possible its use in replacing fossil fuels.
To achieve this goal is necessary to maximize the microalgae yield and know the influence of different variables on their growth. The results of the growth conditions study of the Nannochloropsis oculata, species suitable for the oil production and aquaculture, using two sizes of reactors (6l and 120l) of the type "bubble column" is presented. The main parameters influencing microalgal growth and their interactions are studied through the approach of the design of experiment (DoE).
The growth of microalgae is modelled using the modified Gompertz equation. This model allowed calculating the specific speed of growth and to determinate the biomass and oil productivity.
The evaluation of the influence of nitrates concentration has made to assess the use of the Nannochloropsis oculata, contextually in the treatment of waste water and in the oil production. The energy characterization of the algal biomass, obtained in the different operating conditions, complete the study.
In summary, the plant, residual and algal biomass, may be relevant not only for the energy sector, but also for the whole agro-industrial economy of the island. The biomasses are totally renewable raw materials and can allow to completely rethinking the agro-industrial production.
A new approach is the application of the biorefinery concept that allows designing integrated production systems with the production of foods, animal feeds, chemicals and energy, achieving great benefits from an economical and environmental point of view.
A plant biomass, widely available in Sardinia, is represented by the artichoke that residues at the end of the culture. Sardinia is, in fact, the third largest producer of this Italian Ortiva with about 12,000 ha divided into four basins in different parts of the region. The crop wastes amount, is estimated prudentially, to about 180,000 t a-1 and is theoretically possible to exploit these to obtain energy, chemicals such as inulin and phenolic substances for food and pharmaceutical industry, fresh and processed vegetable fibres for packaging use.
This will require in the future a specific research to assess the real feasibility, but the sector seems to be certainly promising