Ingegnerizzazione di materiali nanostrutturati fotocataliticamente attivi

Il lavoro oggetto di questa tesi è rivolto alla sintesi e alla caratterizzazione di materiali nanostrutturati costituiti da biossido di titanio e ossido di silicio da utilizzare come fotocatalizzatori per la depurazione delle acque. L’obiettivo è stato quello di realizzare un sistema in fase solida costituito da una matrice inerte, la silice, e una fase fotocataliticamente attiva, la nano-TiO2. Tale sistema si inserisce perfettamente nel settore di ricerca che studia la sintesi colloidale di eterostrutture nano e micro cristalline che combinano materiali diversi in un’unica particella. Il progetto nasce all’interno dell’ISTEC-CNR di Faenza, dove è stato svolto il lavoro.

Sviluppo e caratterizzazione di scaffolds polimerici a base di gelatina e nanocellulosa per la rigenerazione dei tessuti

L’ingegneria tissutale rappresenta oggi una delle tematiche più importanti di ricerca in ambito medico-ingegneristico. Questa disciplina si pone come obiettivo di far fronte alla mancanza, sostituzione o riparazione di tessuto attraverso lo sviluppo di scaffolds opportunamente ottimizzati. I polimeri naturali rappresentano una classe di materiali particolarmente indicata per soddisfare i requisiti richiesti soprattutto per la biocompatibilità che spesso li caratterizza. La gelatina è uno dei materiali che si presta alla realizzazione di scaffolds innovativi ad altissima biocompatibilità nonostante le scarse proprietà meccaniche e la facilità di degradazione. Proprio per questo è possibile migliorarne le prestazioni attraverso l’ottimizzazione di processi di blending con altri polimeri, in questo caso le nanofibre di cellulosa e l’impiego di agenti reticolanti. Lo scopo di questo lavoro di tesi, svolto presso l’Istituto di Scienza e Tecnologia dei Materiali Ceramici (ISTEC-CNR) di Faenza, è la progettazione, lo sviluppo e la caratterizzazione di scaffolds polimerici porosi a base di gelatina e nanocellulosa opportunamente reticolati per un ampio range di applicazioni nell’ambito dell’ingegneria tissutale. A questo scopo, sono stati sviluppati cinque dispositivi 3D porosi, ottenuti tramite liofilizzazione, che differiscono per il tipo di processo reticolante applicato. Il progetto ha previsto una prima fase di ricerca bibliografica che ha permesso di conoscere lo stato dell’arte sull’argomento trattato. Si è potuto così procedere alla realizzazione degli scaffolds e a una prima caratterizzazione di carattere chimico-fisico e morfologico. A questo punto, sulla base dei dati ottenuti, sono stati scelti i campioni su cui effettuare ulteriori caratterizzazioni meccaniche. In ultimo, sono stati analizzati e rielaborati tutti i risultati.

The Revised Transactional Model (RTM) of occupational stress and coping : an improved process approach

Despite more than three decades of research, there is a limited understanding of the transactional processes of appraisal, stress and coping. This has led to calls for more focused research on the entire process that underlies these variables. To date, there remains a paucity of such research. The present study examined Lazarus and Folkman’s (1984) transactional model of stress and coping. One hundred and twenty nine Australian participants with full time employment (i.e. nurses and administration employees) were recruited. There were 49 male (age mean = 34, SD = 10.51) and 80 female (age mean = 36, SD = 10.31) participants. The analysis of three path models indicated that in addition to the original paths, which were found in Lazarus and Folkman’s transactional model (primary appraisal-->secondary appraisal-->stress-->coping), there were also direct links between primary appraisal and stress level time one and between stress level time one to stress level time two. This study has provided additional insights into the transactional process which will extend our understanding of how individuals appraise, cope and experience occupational stress.

Caratterizzazione proteomica di fluidi e tessuti in diverse condizioni fisio-patologiche

This thesis has been focused on the proteomic characterization of human saliva from donors of different ages, starting from birth up to adult age, and pediatric brain tumor tissues. The first study has been performed in order to compare the acid-insoluble fraction of saliva from preterm with at-term newborns and adults and establish if differences exist. In the second study medulloblastoma and pilocytic astrocytoma pediatric brain tumor extracts have been compared. In both studies 2- DE analysis was coupled with high resolution tandem mass spectrometry (MS/MS). The proteomic characterization of the acid-insoluble fractions of saliva from preterm newborns allowed to integrate data previously obtained on the acid-soluble fraction by HPLC-electrospray ionization (ESI)-mass spectrometry (MS), and to evidence several differences between preterm newborns, at-term newborns and adults. Spots differentially expressed between the three groups, according to image analysis of the gels, were submitted to in-gel tryptic digestion and the peptide mixture analyzed by high performance HPLC-ESI-MS/MS for their characterization. By this strategy, we identified three over-expressed proteins in atterm newborns with respect to preterm newborns and adults (BPI fold-containing family A member 1, two proteoforms of annexin A1, and keratin type 1 cytoskeletal 13), and several over-expressed proteins in adults (fatty acid-binding protein, S100A6, S100A7, two proteoforms of S100A9, several proteoforms of prolactin-inducible protein, Ig kappa chain, two proteoforms of cystatin SN, one proteoform of cystatin S and several proteoforms of α-amylase 1). Moreover, for the first time, it was possible to assign by MS/MS four spots of human saliva 2-DE, already detected by other authors, to different proteoforms of S100A9. The strategy applied used a sequential staining protocol to the 2-DE gels, first with Pro-Q Diamond, that allows specific detection of phosphoproteins, and successively with total protein SYPRO Ruby stain. In the second study, proteomic analysis of two pediatric brain tumor tissues pointed out differences between medulloblastoma, the prevalent malignant tumor in childhood, and pilocytic astrocytoma, the most common, that only rarely shows a malignant progression. Due to the limited availability of bioptic tissue, the study was performed on pooled tumor tissues, and was focused on acid-insoluble fraction to integrate the characterization performed by a group of colleagues in Rome on the acid-soluble fraction by high performance HPLC-ESI-MS/MS. The results indicated that the two tumors exhibit different proteomic profiles and evidenced interesting differential expression of several proteins. Among them, peroxiredoxin- 1, peptidyl-prolyl cis–trans isomerase A, heterogeneous nuclear ribonucleoproteins A2/B1, mitochondrial isoform of malate dehydrogenase, nucleoside diphosphate kinase A, glutathione S-transferase P and fructose bisphosphate aldolase A resulted significantly over-expressed in medulloblastoma while glial fibrillary acidic protein, serotransferrin, α crystallin B chain, ferritin light chain, annexin A5, fatty acid-binding protein (brain), sorcin and apolipoprotein A-I resulted significantly over-expressed in pilocytic astrocytoma. In conclusion, the work done allowed to evidence the usefulness of using an integrated bottom-up/top-down approach, based on 2-DE-MS analysis and high performance MS in order to obtain a complete characterization of the proteome under investigation, revealing and identifying, not only peptides and small proteins, but also proteins with higher MW, that often it is not possible to identify by using exclusively a top-down ESI-MS approach.

Caratterizzazione geo-petrografica, petrologica e geochimica di rocce anatettiche del nord Sardegna

The 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.

Implementação do algoritmo (RTM) para processamento sísmico em arquiteturas não convencionais

With the growth of energy consumption worldwide, conventional reservoirs, the reservoirs called "easy exploration and production" are not meeting the global energy demand. This has led many researchers to develop projects that will address these needs, companies in the oil sector has invested in techniques that helping in locating and drilling wells. One of the techniques employed in oil exploration process is the reverse time migration (RTM), in English, Reverse Time Migration, which is a method of seismic imaging that produces excellent image of the subsurface. It is algorithm based in calculation on the wave equation. RTM is considered one of the most advanced seismic imaging techniques. The economic value of the oil reserves that require RTM to be localized is very high, this means that the development of these algorithms becomes a competitive differentiator for companies seismic processing. But, it requires great computational power, that it still somehow harms its practical success. The objective of this work is to explore the implementation of this algorithm in unconventional architectures, specifically GPUs using the CUDA by making an analysis of the difficulties in developing the same, as well as the performance of the algorithm in the sequential and parallel version

Escalabilidade Paralela de um Algoritmo de Migração Reversa no Tempo (RTM) Pré-empilhamento

The seismic method is of extreme importance in geophysics. Mainly associated with oil exploration, this line of research focuses most of all investment in this area. The acquisition, processing and interpretation of seismic data are the parts that instantiate a seismic study. Seismic processing in particular is focused on the imaging that represents the geological structures in subsurface. Seismic processing has evolved significantly in recent decades due to the demands of the oil industry, and also due to the technological advances of hardware that achieved higher storage and digital information processing capabilities, which enabled the development of more sophisticated processing algorithms such as the ones that use of parallel architectures. One of the most important steps in seismic processing is imaging. Migration of seismic data is one of the techniques used for imaging, with the goal of obtaining a seismic section image that represents the geological structures the most accurately and faithfully as possible. The result of migration is a 2D or 3D image which it is possible to identify faults and salt domes among other structures of interest, such as potential hydrocarbon reservoirs. However, a migration fulfilled with quality and accuracy may be a long time consuming process, due to the mathematical algorithm heuristics and the extensive amount of data inputs and outputs involved in this process, which may take days, weeks and even months of uninterrupted execution on the supercomputers, representing large computational and financial costs, that could derail the implementation of these methods. Aiming at performance improvement, this work conducted the core parallelization of a Reverse Time Migration (RTM) algorithm, using the parallel programming model Open Multi-Processing (OpenMP), due to the large computational effort required by this migration technique. Furthermore, analyzes such as speedup, efficiency were performed, and ultimately, the identification of the algorithmic scalability degree with respect to the technological advancement expected by future processors

Monitoring of cure kinetic prepreg and cure cycle modeling

Cure kinetic model is an integral part of composite process simulation, which is used to predict the degree of curing and the amount of the generated heat. The parameters involved in kinetic models are usually determined empirically from isothermal or dynamic differential scanning calorimetry (DSC) data. In this work, DSC and rheological techniques were used to investigate some of the kinetic parameters of cure reactions of carbon/F161 epoxy prepreg and to evaluate the cure cycle used to manufacture polymeric composites for aeronautical applications. As a result, it was observed that the F161 prepreg presents cure kinetic with total order 1.2-1.9. (c) 2006 Springer Science + Business Media, Inc.

Evaluation of stitched fabric composite processed by RTM in quasi-static test

Stitched fabrics have been widely studied for potential application in aircraft structures since stitch yarns offer improvements in the out-of-plane mechanical properties and also can save time in the lay up process. The down side of stitch yarns came up in the manufacturing process of fabric in which defects introduced by the needle movement creating fiber-free-zones, fiber breakage and misalignment of fibers. The dry stitched carbon fabric preform has mainly been used in the Resin Transfer Molding (RTM) process which high fiber content is aimed, those defects influence negatively the injection behavior reducing the mechanical properties of final material. The purpose of this research work focused on testing in quasi-static mechanical mode (in-plane tension) of a monocomponent resin CYCOM (R) 890 RTM/carbon fiber anti-symmetric quadriaxial fabric stitched by PE 80Dtex yarn processed by RTM. The evaluation consisted in comparing the scatter of the quasi-static test with the attenuation of ultrasonic maps, which show the path of the resin and possible dry spots considering that interference of yarn in resin flow is detectable in ultrasonic measurement. Microscopic analysis was also considered for further evaluation in case of premature failure. (C) 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of ICM11

Characterization of cure of carbon/epoxy prepreg used in aerospace field

Carbon/epoxy 8552 prepreg is a thermoplastic toughened high-performance epoxy being used in the manufacture of advanced army material. Understanding the cure behavior of a thermosetting system is essential in the development and optimization of composite fabrication processes. The cure kinetics and rheological behavior were evaluated using a differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and a rheometer. Values of the kinetic parameters were obtained from dynamic DSC scans using an nth order reaction model. Rheological measurements as a function of temperature and time were made for the prepreg system. The manufacturer's recommended cure cycle was evaluated and considered adequate to consolidated the studied system.