Studio della resistenza a fatica di giunzioni saldate

In questo lavoro si è analizzata la resistenza a fatica di giunti saldati con cordoni d’angolo. Dopo una prima parte dove sono state descritte brevemente le due norme principali di riferimento per la verifica a fatica dei giunti saldati: l’Eurocodice 3 e la norma per i carrelli ferroviari ERRI B 12/RP 60, si è fatto un quadro riassuntivo sullo stato dell’arte dei metodi di verifica a fatica delle saldature. Dopo di che si è passati all’analisi sperimentale su componenti ferroviari. I provini consistono in tubi cilindrici uniti ad una piastra quadrata mediante saldatura a cordone d’angolo; le prove sono state eseguite con i tubi soggetti a flessione pura, flesso-torsione e torsione pura. Acquisiti i risultati sperimentali si sono ottenute le varie curve di fatica S-N, tali curve sono state poi confrontate con le curve ottenute mediante il software di simulazione 3D ‘Virtual Lab Durability’ e con le curve contenute nell’Eurocodice 3. Sia le curve S-N ottenute con ‘Virtual Lab Durability’ sia le curve SN dell’Eurocodice 3 presentano una pendenza maggiore rispetto alle curve sperimentali, le curve fornite dall’Eurocodice 3 presentano un ampio margine di sicurezza rispetto ai dati sperimentali. This thesis deals with fatigue strength of seam welds. At the beginning of the work the main rules about the fatigue seam welds strength are described according to: the Eurocode 3 and the ERRI B 12/RP 60 (that deals with railway bogies); then a brief summary of technical literature of methods for the analysis of welds strength is reported. After that experimental tests on railway component were started. This components are cylindrical pipes welded to a square plate by seam weld. The tests have been made with the pipes load by pure bending, by bending-torsion and by pure torsion. At this point the S-N curves obtained by experimental data were compared to the curves obtained by 3D simulation software ‘Virtual Lab Durability’ and with the ones given by the Eurocode 3. Both the S-N curves obtained by software and both the ones given by Eurocode 3 are more leaning than the experimental S-N cuves; the SN curves given by the Eurocode 3 appear to be significantly conservative

Abel: Integrating Humanoid Body, Emotions, and Time Perception to Investigate Social Interaction and Human Cognition

Humanoids have been created for assisting or replacing humans in many applications, providing encouraging results in contexts where social and emotional interaction is required, such as healthcare, education, and therapy. Bioinspiration, that has often guided the design of their bodies and minds, made them also become excellent research tools, probably the best platform by which we can model, test, and understand the human mind and behavior. Driven by the aim of creating a believable robot for interactive applications, as well as a research platform for investigating human cognition and emotion, we are constructing a new humanoid social robot: Abel. In this paper, we discussed three of the fundamental principles that motivated the design of Abel and its cognitive and emotional system: hyper-realistic humanoid aesthetics, human-inspired emotion processing, and human-like perception of time. After reporting a brief state-of-the-art on the related topics, we present the robot at its stage of development, what are the perspectives for its application, and how it could satisfy the expectations as a tool to investigate the human mind, behavior, and consciousness

Small Firms, Corruption, and Demand for Credit. Evidence from the Euro Area

In this paper, we aim to assess how the quality of the institutional environment \u2013 identified according to the level of corruption perceived in a country \u2013 may affect the access to credit for micro, small, and medium-sized enterprises (MSMEs). Based on a sample of 68,115 observations \u2013 drawn from the ECB-SAFE survey \u2013 related to MSMEs chartered in 11 euro area countries, we investigate whether the level of corruption affects their demand for bank loans during the period 2009\u20132014. Overall, we find that the degree of corruption seems to play a role in the applications for bank loans when small firms are under investigation. Interestingly, results highlight that small businesses chartered in highly corrupt countries face a greater probability of self-restraint regarding their loan applications (about 7.4%) than small firms located in low-corruption economies (around 6%). The results are robust to various model specifications and econometric methodologies. Our findings suggest that anti-corruption policies and measures enhancing transparency in the economy may be crucial in reducing the negative spillovers generated by a low-quality institutional environment on the access to credit by small firms

Role of Fibre in Nutritional Management of Pancreatic Diseases

The role of fibre intake in the management of patients with pancreatic disease is still controversial. In acute pancreatitis, a prebiotic enriched diet is associated with low rates of pancreatic necrosis infection, hospital stay, systemic inflammatory response syndrome and multiorgan failure. This protective effect seems to be connected with the ability of fibre to stabilise the disturbed intestinal barrier homeostasis and to reduce the infection rate. On the other hand, in patients with exocrine pancreatic insufficiency, a high content fibre diet is associated with an increased wet fecal weight and fecal fat excretion because of the fibre inhibition of pancreatic enzymes. The mechanism by which dietary fibre reduces the pancreatic enzyme activity is still not clear. It seems likely that pancreatic enzymes are absorbed on the fibre surface or entrapped in pectin, a gel-like substance, and are likely inactivated by anti-nutrient compounds present in some foods. The aim of the present review is to highlight the current knowledge on the role of fibre in the nutritional management of patients with pancreatic disorders

Il Pascolamento nell'alimentazione di vacche in lattazione: effetto dell'impiego di una tecnica di pascolamento limitata a 2 ore giornaliere

In a trial carried out on 154 Holstein Friesian high productive cows (73 house feed and 81 with supplementa ry pasture for 2 h/d) with unifeed system, the authors found no significative differences between two groups in daily milk yield (kg 29.7 ± 7.2 vs kg 29.6 ± 7.8), in butterfat (2.97% ± 0.39% vs 2.92% ± 0.47%) and protein (3.03% ± 0.21 % vs 3.00 ± 0.20%) content and in health state: furthermore they estimated about 2 3 kg the D,M. daily intake from pasture grass

Effect of HXT1 and HXT7 hexose transporter overexpression on wild-type and lactic acid producing Saccharomyces cerevisiae cells

<p>Abstract</p> <p>Background</p> <p>Since about three decades, <it>Saccharomyces cerevisiae </it>can be engineered to efficiently produce proteins and metabolites. Even recognizing that in baker's yeast one determining step for the glucose consumption rate is the sugar uptake, this fact has never been conceived to improve the metabolite(s) productivity.</p> <p>In this work we compared the ethanol and/or the lactic acid production from wild type and metabolically engineered <it>S. cerevisiae </it>cells expressing an additional copy of one hexose transporter.</p> <p>Results</p> <p>Different <it>S. cerevisiae </it>strains (wild type and metabolically engineered for lactic acid production) were transformed with the <it>HXT</it>1 or the <it>HXT</it>7 gene encoding for hexose transporters.</p> <p>Data obtained suggest that the overexpression of an Hxt transporter may lead to an increase in glucose uptake that could result in an increased ethanol and/or lactic acid productivities. As a consequence of the increased productivity and of the reduced process timing, a higher production was measured.</p> <p>Conclusion</p> <p>Metabolic pathway manipulation for improving the properties and the productivity of microorganisms is a well established concept. A high production relies on a multi-factorial system. We showed that by modulating the first step of the pathway leading to lactic acid accumulation an improvement of about 15% in lactic acid production can be obtained in a yeast strain already developed for industrial application.</p

SEAI: Social Emotional Artificial Intelligence Based on Damasio's Theory of Mind

A socially intelligent robot must be capable to extract meaningful information in real-time from the social environment and react accordingly with coherent human-like behaviour. Moreover, it should be able to internalise this information, to reason on it at a higher abstract level, build its own opinions independently and then automatically bias the decision-making according to its unique experience. In the last decades, neuroscience research highlighted the link between the evolution of such complex behaviour and the evolution of a certain level of consciousness, which cannot leave out of a body that feels emotions as discriminants and prompters. In order to develop cognitive systems for social robotics with greater human-likeliness, we used an "understanding by building" approach to model and implement a well-known theory of mind in the form of an artificial intelligence, and we tested it on a sophisticated robotic platform. The name of the presented system is SEAI (Social Emotional Artificial Intelligence), a cognitive system specifically conceived for social and emotional robots. It is designed as a bio-inspired, highly modular, hybrid system with emotion modelling and high-level reasoning capabilities. It follows the deliberative/reactive paradigm where a knowledge-based expert system is aimed at dealing with the high-level symbolic reasoning, while a more conventional reactive paradigm is deputed to the low-level processing and control. The SEAI system is also enriched by a model which simulate the Damasio's theory of consciousness and the theory of Somatic Markers. After a review of similar bio-inspired cognitive systems, we present the scientific foundations and their computational formalisation at the basis of the SEAI framework. Then, a deeper technical description of the architecture is disclosed underlining the numerous parallelisms with the human cognitive system. Finally, the influence of artificial emotions and feelings, and their link with the robot's beliefs and decisions have been tested in a physical humanoid involved in Human-Robot Interaction (HRI)