Design, simulation and development of a decentralized control for a robotic manipulator

The objective of this thesis is to design, develop and test a decentralized control for the YouBot. This robot is composed by an omnidirectional mobile platform on which a five – axis robot arm with a two – finger gripper is installed. In the first step the YouBot arm’s performance is analysed and the problems are verified and mentioned by the community. The stat of the art is assessed. The available hardware and software is analysed, as well as the temporal performances, the responses of the system, the optimal sampling time and the torque characterization. Subsequently the COM (center of mass) for each link, is estimated, through a least squares algorithm, and the gravity compensation is implemented. After this a hybrid motion/force decentralized control based on Newton – Eulero dynamics is realized. The control algorithm is tested in simulation and on the real Youbot Manipulator. The obtained results have been analyzed and discussed

effect of thermo mechanical processes on microstructure evolution in austenitic stainless steels

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Sharp second-order regularity for widely degenerate elliptic equations

We consider local weak solutions of widely degenerate or singular elliptic PDEs of the type \begin{equation*} -\,\mathrm{div}\left((\vert Du\vert-\lambda)_{+}^{p-1}\frac{Du}{\vert Du\vert}\right)=f \,\,\,\,\,\,\, \text{in}\,\,\Omega, \end{equation*} where $\Omega$ is an open subset of $\mathbb{R}^{n}$ for $n\geq2$, $\lambda$ is a positive constant and $(\,\cdot\,)_{+}$ stands for the positive part. We establish some higher differentiability results, under essentially sharp conditions on the datum $f$. Our results improve the one contained in [8] for $\lambda=0$ and $p>2$, and give back a result similar to that in [12] for $1 < p \le 2$.Comment: This version contains a slight modification of the proof of Theorem 1.1, compared with the previous version. The conclusions of the teorem are the sam

Analysis of Forming Parameters Involved in Plastic Deformation of 441 Ferritic Stainless Steel Tubes

A welded stainless steel tube is a component used in several industrial applications. Its manufacturing process needs to follow specific requirements based on reference standards. This calls for a predictive analysis able to face some critical issues affecting the forming process. In this paper, a model was adopted taking into account the tube geometrical parameters that was able to describe the deformation process and define the best industrial practices. In this paper, the effect of different process parameters and geometric constraints on ferritic stainless steel pipe deformation is studied by finite element method (FEM) simulations. The model sensitivity to the input parameters is reported in terms of stress and tube thinning. The feasibility of the simulated process is assessed through the comparison of Forming Limit Diagrams. The comparison between the calculated and experimental results proved this approach to be a useful tool in order to predict and properly design industrial deformation processes

Statistical modelling of recrystallization and grain growth phenomena in stainless steels: effect of initial grain size distribution

Abstract Modelling and simulation of recrystallization, grain growth, and related phenomena are important tools for the fundamental understanding of microstructural evolution that takes place during the annealing and thermomechanical processing of steel. It is also important for the prediction of engineering properties. In this paper, the evolution of mean grain radius and the recrystallized volume fraction of steel was modelled using the statistical theory of grain growth originally developed by Lücke [1] and here integrated to take into consideration the effect of recrystallization. In particular, the effect of one free input parameter (initial distribution of grain radii) of the model is analysed without taking into account the textures effect

Mapping combined wildfire and heat stress hazards to improve evidence-based decision making

Heat stress and forest fires are often considered highly correlated hazards as extreme temperatures play a key role in both occurrences. This commonality can influence how civil protection and local responders deploy resources on the ground and could lead to an underestimation of potential impacts, as people could be less resilient when exposed to multiple hazards. In this work, we provide a simple methodology to identify areas prone to concurrent hazards, exemplified with, but not limited to, heat stress and fire danger. We use the combined heat and forest fire event that affected Europe in June 2017 to demonstrate that the methodology can be used for analysing past events as well as making predictions, by using reanalysis and medium-range weather forecasts, respectively. We present new spatial layers that map the combined danger and make suggestions on how these could be used in the context of a Multi-Hazard Early Warning System. These products could be particularly valuable in disaster risk reduction and emergency response management, particularly for civil protection, humanitarian agencies and other first responders whose role is to identify priorities during pre-interventions and emergencies

Elementi metodologici per una riflessione sui dati dell'epidemia di sars-cov-2

Findings of the seroprevalence survey conducted by Istat between May 25 and July 15 2020, on a sample of 64,660 people, show that only 2.5% of Italian people developed antibodies to SARS-CoV-2, a prevalence very far from the hypothesis of achieving herd immunity. Starting from the comment on these results, we summarized some of the main indicators used to evaluate the epidemic curves (R, R0, Rt) and the concept of herd immunity. R0, basic reproduction number, represents the average number of secondary cases we expect to observe from a single primary case in a population with no immunity to the disease before prevention and containment measures have been planned. Rt, effective reproduction number, is calculated over time and considers how the outbreak progresses, as a result of the containment measures and of people who might have gained immunity, because they survived from infection or were vaccinated. We presented the issue of herd immunity, or community immunity, a state of protection in a population obtained because the number of people in the population who are immune to infectious disease is above a critical threshold, resulting in a protection even for those who are not immune

MENTAL ILLNESS AND PREJUDICES IN PSYCHIATRIC PROFESSIONALS Data from the social stigma questionnaire for psychiatric professionals: a multicentre study

The prejudices about mental illness and the related social stigma are still present in the population. People suffer from both the disease and the marginalization behaviors implemented by the "so-called healthy" towards them and their relatives. Even psychiatric professionals can get sick and suffer for the same reason. The authors of this multicentric study have focused their attention on the presence or absence of groups of psychiatric pathologies among the "insiders". The most frequent pathologies encountered were the mood and anxiety disorders, in a percentage similar to that of the general population. To continue the research on the stigma begun in a previous study, the authors asked themselves if there could be prejudices and/or stigma among psychiatric professionals towards sick colleagues, how they relate in the workplace and how they react to the behavior of colleagues. The stigma questionnaire has been used on psychiatric professionals, and 130 Italian colleagues were tested in the provinces of Avellino, Brindisi and Trento. The data were compared with those of the research on the stigma "Thinking of Psychiatric Disorders as" Normal "Illness" (Tavormina et al. 2016) and it emerged that among the attending professionals there are no statistically significant behaviors of marginalization, exclusion or stigma against sick colleagues, even if there is a certain discomfort in working together. Above all, it emerged that 80% of the interviewees, who have had work experience with sick colleagues, have replied that the latter can treat those who are also sick of their own disease, thus showing esteem and confidence in their work, in analogy with the Jungian thesis of the "wounded Healer" in the myth of the centaur Chiron

Factors associated with the subjective health complaints among adolescents: Results from the ASSO Project

Objectives. Subjective health complaints (e.g. headache and feeling low) are common among adolescents. The objective of this study was to identify the factors associated with the subjective health of adolescents from a population-based point of view. Material and methods. A sample of 712 students was recruited within the web-based Project ASSO (Adolescents and Surveillance System for the Obesity prevention), funded by the Italian Ministry of Health and piloted in Palermo. A 0-100 quantitative score (arbitrarily named "psychosomatic malaise index") based on the frequency of occurrence of seven subjective health complaints was created and used as outcome; socio-demographic characteristics, medical items and lifestyle data were collected as potential explanatory variables. Associations were evaluated through a bivariate analysis first, and a multiple linear regression model afterwards by correcting for confounders. Results. The psychosomatic malaise index averaged 49.0 within the girls and 36.8 within the boys. After adjustment, the psychosomatic malaise index was confirmed to be significantly higher in the females, subjects with a diagnosed disease, smokers and alcohol consumers. Conclusions. Beyond the female gender, incorrect lifestyles such smoking and drinking alcohol may play an important role in the quality of life of adolescents, and thus preventive actions by the public health services should be addressed mainly to avoid such habits in young populations. The work has been performed within the Adolescents and Surveillance System for the Obesity prevention (ASSO) Project (code GR-2008-1140742, CUP I85J10000500001), a project funded by the Italian Ministry of Health