Peripheral ameloblastoma: use of cytokeratin 19 and Ber-EP4 to distinguish it from basal cell carcinoma

n/

Investigating Complex Geometrical Features in LPBF-Produced Parts: A Material-Based Comparison Between Different Titanium Alloys

The Ti–6Al–4V (Ti64) alloy is a well-established material to be processed via laser powder bed fusion (LPBF). Recently, other α + β titanium alloys are receiving attention, such as Ti–6Al–2Sn–4Zr–6Mo (Ti6246). Their typical industrial fields of application (aerospace, automotive), often require critical design choices, such as low wall thicknesses and hollow channels. Thus, a comparative analysis between these two competitor alloys in terms of processability was conducted in this work. To do so, specific sample designs were developed. The specimens were analyzed in terms of geometrical compliance with the initial design, porosity, and microstructure. A correlation between the width of the specimens and their porosity, micro- structure and hardness was found. Overall, both the alloys proved to be well processable, even for very low wall thickness (300 μm) and channel diameter (1 mm) values. Nevertheless, the Ti6246 alloy seemed to behave better in specific scenarios. For instance, some Ti64 specimens provided delamination. The hollow channels proved to be challenging for both materi- als, mainly due to the high amount of residual powder particles adhered to the upper part of the holes. This works aims at giving a materials perspective on process-related issues, considering the LPBF-induced defectology and microstructural variations in these Ti alloys

Bringing the Embedded Systems Industry Towards Open Source: the SHARE project experience

International audienceOpen source software adoption in the embedded systems domain is gaining growing interest within the european industrial and academic communities due to the significant benefits it brings in terms of flexibility and cost reduction.Nonetheless, scepticism about open source as a viable option to support critical business functions still holds, since its decentralized and distributed development model makes quality evaluation and assessment hard to achieve. This paper reports the SHARE project experience, aimed at facilitating and promoting the use of open source software in the embedded systems industry. Performed activities, proposed methodology and achieved results are presented, along with lessons learned to exploit for enabling further initiatives in the next future

Electrochemistry of fuming sulphuric acids : III. Mechanism of the cathodic reactions on platinum

The cathodic potential-decay process on platinum electrodes in oleums has been investigated by means of a rotating disk. The non-stady parameters are compared with those already reported under steady-state conditions. Both results are discussed in terms of a general reaction mechanism comprising various consecutive as well as alternative steps, considering that the main cathodic product is sulphur dioxide. The SO3-containing species acts as a depolarizer by reacting with hydrogen atoms adsorbed on the electrode surface.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Electrochemistry of fuming sulphuric acids : II. Current/voltage characteristics at a platinum rotating disk electrode

Anodic and cathodic processes involved in the electrolysis of different oleums were studied on platinum rotating disk electrodes at 25 and 5O°C, in a range of rotation speeds from 260 to 2000 rpm. Anodic processes do not change with the rate of stirring. The cathodic process occurring at low overvoltages comprises a limiting current linearly related to the concentration of free Soa. The anodic and cathodic Tafel lines previously determined with the electrolyte at rest are confirmed. It is concluded that the cathodic process occurring at low overvoltages involves the reduction of a solvated SOa. The effective diffusion coefficient of the latter is evaluated.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Electrochemical study of fuming sulphuric acids : I. Kinetic parameters of the anodic and cathodic reactions on platinum electrodes

Kinetic parameters related to the anodic and cathodic processes in the electrolysis of fuming sulphuric acids on bright platinum and platinized platinum electrodes have been established, the electrolyte being kept at rest. Experiments cover temperatures from 25 to 70°C and oleums with a sulphur trioxide concentration from about 5 to 28 per cent. The yields of the different anodic and cathodic products mentioned in a previous publication have been confirmed and results for others are given. The anodic reaction is characterized by current/voltage curves which fit Tafel plots at high voltage, with a slope close to 2·3(2RT/F). The cathodic current/voltage curves plotted according to the Tafel equation exhibit three different regions. (i) At voltages lower than 0·4 V, a Tafel line with a slope of 2·3(RT/F) is observed. (ii) At about 0·5 V a limiting current is shown. These regions are related to the reduction of sulphur trioxide. (iii) At voltages larger than 0·7 V, a clear Tafel line region appears again, involving a 2·3 (2RT/F) slope. The latter is related to the evolution of hydrogen and the simultaneous presence of a blue tinge in the oleums, which is attributed to the formation of disulphur trioxide.Les paramètres cinétiques des processus anodiques et cathodiques dans l'électrolyse des oléums sur des électrodes de platine poli et platine platinisé ont été établis, l'électrolyte étant au repos. Les expériences ont été réalisées a des températures de 25 à 70°C avec une concentration de trioxyde de soufre de 5 à 28 pour cent. Les rapports des différents produits anodiques et cathodiques mentionnés dans une publication antérieure ont été confirmés; on présente aussi d'autres résultats. Les courbes courant/voltage de la réaction anodique suivent la loi de Tafel à tensions élevées, avec une pente proche de 2,3(2RT/F). Les courbes cathodiques tracées de la même façon montrent trois régions différentes. (i) A des tensions de moins de 0,4 V on observe une droite avec un pente 2,3(RT/F). (ii) A des tensions d'environ 0,5 V, on a trouvé un courant limite. Ces deux régions (i) et (ii) sont déterminées par la réduction du trioxide de soufre. (iii) A des tensions de plus de 0,7 V on a retrouvé une droite de Tafel avec une pente de 2,3(2RT/F). Celle-ci est on relation avec l'évolution de l'hydrogène et l'apparition simultanée d'une teinte bleue dans l'électrolyte, qu'on a attribuée a la formation de trioxyde de disoufre.Man ermittelte die kinetischen Parameter der Anoden- und Kathodenvorgänge bei der Elektrolyse von rauchender Schwefelsäure an Platin- und platinierten Platinelektroden in ruhendem Elektrolyten. Die Versuchstemperatur wurde zwischen 25 und 70°C, der Schwefeltrioxydegehalt des Oleums zwischen ungefähr 5 und 28 %. variiert. Die Zusammensetzung der kathodischen und anodischen Reaktionsprodukte, wie sie in einer früheren Arbeit beschrieben wurden, konnten bestätigt werden, daneben werden die Ergebnisse weiterer Versuche bekanntegegeben. Die anodische Reaktion ist gekennzeichnet durch Strom-Spannungskurven, welche bei hohen Spannungen Tafel-Charakter mit einer Steigung von beinahe 2,3(2RT/F) annehmen. Die als Tafel-Beziehungen aufgezeichneten kathodischen Strom-Spannungskurven weisen drei verschiedene Gebiete auf. (A) Bei Spannungen unterhalb von 0,4 V erhält man eine Gerade mit der Steigung 2,3(2RT/F). (B) Bei ungefähr 0,5 V tritt ein Grenzstrom auf, welcher von der Reduktion dos Schwefeltrioxyds/herrührt. (C) Bei Spannungen oberhalb 0,7 V ergibt sich wiederum eine Gerade mit deutlichem Tafel-Charakter und einer Steigung von 2,3(2RT/F). Diese dritte Zone steht in Beziehung zur Wasserstoffentwicklung und zu der gleichzeitigen Blaufärbung des Oleums, welche der Bildung von Schwefelsesquioxyd zugeschrieben wird.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Bubbles and jackets: new scaling bounds in topological group field theories

We use a reformulation of topological group field theories in 3 and 4 dimensions in terms of variables associated to vertices, in 3d, and edges, in 4d, to obtain new scaling bounds for their Feynman amplitudes. In both 3 and 4 dimensions, we obtain a bubble bound proving the suppression of singular topologies with respect to the first terms in the perturbative expansion (in the cut-off). We also prove a new, stronger jacket bound than the one currently available in the literature. We expect these results to be relevant for other tensorial field theories of this type, as well as for group field theory models for 4d quantum gravity.Comment: v2: Minor modifications to match published versio

An innovative approach on directed energy deposition optimization: A study of the process environment's influence on the quality of Ti-6Al-4V Samples

Blown powder additive manufacturing technologies are not restricted to the use of a process chamber. This feature allows to build larger components with respect to conventional powder bed processes. This peculiarity is mostly promising for manufacturing large components or repairing/rebuilding parts of large systems. The main downside of using an open environment, even if a protective shielding gas system is adopted, is the lack of control of process atmosphere. This is particularly critical for titanium alloys which are very sensitive to oxygen/nitrogen pick-up; they have a detrimental effect on ductility, by causing embrittlement and possibly leading to the formation of cracks. It is then important to address how environmental factors, such as process atmosphere and platform temperature, impact not only on the processability but also on the final component properties, both from a compositional and mechanical point of view. The correlations between these environmental factors and microstructure, interstitials content, grain size, and hardness were investigated. Moreover, the Hall-Petch equation was then adopted to additive manufacturing microstructures, characterized by a columnar grain morphology, and used to further investigate the relationship intercurring between grains and hardness and how different microstructures might influence this correlation

Improving domiciliary robotic services by integrating the ASTRO Robot in an AmI Infrastructure

This work describes the ECHORD Experiment ASTROMOBILE, a project aimed to design, develop and test a system for favourable independent living, improved quality of life and efficiency of care for senior citizens in domestic environments. The system, composed of a mobile robotic platform (called ASTRO) and an Ambient Intelligent Infrastructure that actively cooperated between them and with the end-user, was designed and implemented with a user-centred design approach, involving different stakeholders. The system was designed to deliver services to users, like drug delivery, stand support, reminding, info-entertainment. The design took advantages of the integration of robotic platforms with smart environments, to provide to users higher quality and localization based services. Senior end-users were involved in the experimentation of the system in the DomoCasa Living Lab and feedbacks were gathered for the technology assessment. Particularly, this paper demonstrates the general feasibility of the ASTROMOBILE system and thanks to users feedbacks its acceptability and usability