STUDI DI OTTIMIZZAZIONE DEI TRATTAMENTI TERMICI SU UNA LEGA AL-SI PER USO AUTOMOBILISTICO

Oggetto di questo lavoro è lo studio di trattamenti termici sulla lega 87S1 (nome commerciale), derivata dalla A357, appositamente modificata per migliorare la sua formabilità allo stato semi-solido. Tale lega è particolarmente idonea ad essere formata attraverso il processo Rheocast per la produzione di componenti soprattutto automobilistici. Per la lega presa in esame le caratteristiche meccaniche migliori sono state ad oggi ottenute con il trattamento brevettato dal produttore, un trattamento T6 con solubilizzazione multistadio seguito da un invecchiamento. La finalità del presente studio è quella di valutare la possibilità di effettuare un trattamento termico più economico di quello proposto senza gravose conseguenze per le proprietà meccaniche. La lega è stata sottoposta a trattamenti termici, prove meccaniche ed indagini microstrutturali di microscopia ottica ed elettronica in scansione. Sono stati studiati diversi trattamenti termici, T5 e T6 non multistadio di durate inferiore rispetto a quello brevettato, ottenendo, in alcuni casi, risultati promettenti in termini di proprietà di interesse ingegneristico. In particolare si è osservato come un semplice trattamento termico di solubilizzazione a 500°C per 4 ore fosse in grado di garantire un buon compromesso fra resistenza meccanica e duttilità a temperatura ambiente

Comparative Study Of High Temperature Workability OF ZM21 And AZ31 Magnesium Alloys

High temperature regime, 300-450?C for Mg-Al-Zn alloys, is currently used in primary processing, such as rolling and extrusion, as well as for secondary operation like forging. The knowledge of temperature and strain rate proper combination (processing window) as well as the microstructure evolution occurring during hot deformation clarifies the relationships between forming variables and final properties of components. Numerous data on AZ31 and few other Mg-Al alloys, produced by laboratory testing, are available in the scientific and technical literature. The ZM21, Mg-2Zn-1Mn, by contrast, is characterized by absolute lack of scientific data. In the alloy the addition of manganese, by suppressing the formation of beta phase, increases the solidus temperature that results in the larger processing window than in AZ31. The benefit requires extensive analysis aimed at optimizing the deformation variables that affect the microstructure refinement under dynamic and static recrystallization. The high-temperature plastic deformation and the microstructure evolution of the ZM21 were thus investigated in the temperature range between 200 and 500?C and results were analysed and compared with those of a conventional heat-treated AZ31

Thin Polymer Brush Decouples Biomaterial's Micro-/Nano-Topology and Stem Cell Adhesion

Surface morphology and chemistry of polymers used as biomaterials, such as tissue engineering scaffolds, have a strong influence on the adhesion and behavior of human mesenchymal stem cells. Here we studied semicrystalline poly(ε-caprolactone) (PCL) substrate scaffolds, which exhibited a variation of surface morphologies and roughness originating from different spherulitic superstructures. Different substrates were obtained by varying the parameters of the thermal processing, i.e. crystallization conditions. The cells attached to these polymer substrates adopted different morphologies responding to variations in spherulite density and size. In order to decouple substrate topology effects on the cells, sub-100 nm bio-adhesive polymer brush coatings of oligo(ethylene glycol) methacrylates were grafted from PCL and functionalized with fibronectin. On surfaces featuring different surface textures, dense and sub-100 nm thick brush coatings determined the response of cells, irrespective to the underlying topology. Thus, polymer brushes decouple substrate micro-/nano-topology and the adhesion of stem cells

Personalizing Cancer Pain Therapy: Insights from the Rational Use of Analgesics (RUA) Group

Introduction: A previous Delphi survey from the Rational Use of Analgesics (RUA) project involving Italian palliative care specialists revealed some discrepancies between current guidelines and clinical practice with a lack of consensus on items regarding the use of strong opioids in treating cancer pain. Those results represented the basis for a new Delphi study addressing a better approach to pain treatment in patients with cancer. Methods: The study consisted of a two-round multidisciplinary Delphi study. Specialists rated their agreement with a set of 17 statements using a 5-point Likert scale (0 = totally disagree and 4 = totally agree). Consensus on a statement was achieved if the median consensus score (MCS) (expressed as value at which at least 50% of participants agreed) was at least 4 and the interquartile range (IQR) was 3–4. Results: This survey included input from 186 palliative care specialists representing all Italian territory. Consensus was reached on seven statements. More than 70% of participants agreed with the use of low dose of strong opioids in moderate pain treatment and valued transdermal route as an effective option when the oral route is not available. There was strong consensus on the importance of knowing opioid pharmacokinetics for therapy personalization and on identifying immediate-release opioids as key for tailoring therapy to patients’ needs. Limited agreement was reached on items regarding breakthrough pain and the management of opioid-induced bowel dysfunction. Conclusion: These findings may assist clinicians in applying clinical evidence to routine care settings and call for a reappraisal of current pain treatment recommendations with the final aim of optimizing the clinical use of strong opioids in patients with cancer

Valutazione di un'irroratrice a tunnel nei trattamenti al vigneto

Una delle vie seguite dai costruttori di irroratrici per ridurre la dispersione di prodotto \ue8 quella di dotare la macchina di schermi di protezione e intercettazione dello spray in eccesso. Questo studio analizza i risultati di prove di campo su di un prototipo di questo tipo, impiegato in due fasi di sviluppo vegetativo, in confronto con un atomizzatore classico. I risultati dimostrano un\u2019altissima efficienza del sistema di recupero del liquido fuori bersaglio, che ha consentito di ridurre le perdite a terra a percentuali inferiori al 12% del distribuito. Il sistema si \ue8 dimostrato particolarmente valido con vegetazione scarsa, laddove le macchine tradizionali disperdono di pi\uf9. L\u2019uniformit\ue0 di distribuzione e il grado di copertura sono risultate buone a tutte le quote ed in linea con quelle della macchina tradizionale, nonostante il minor volume irrorato

Legalità e comunicazione. Una sfida ai processi di vittimizzazione.

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