Investigating the Thermo-Mechanical Behavior of a Ceramic Matrix Composite Wing Leading Edge by Sub-Modeling Based Numerical Analyses

The thermo-structural design of the wing leading edge of hypersonic vehicles is a very challenging task as high gradients in thermal field, and hence high thermal stresses, are expected. Indeed, when employing passive hot structures based thermal protection systems, very high temperatures (e.g., 1400 °C) are expected on the external surface of the wing leading edge, while the internal structural components are required to not exceed a few hundred degrees Celsius (e.g., 400 °C) at the interface with the internal cold structure. Hence, ceramic matrix composites (CMC) are usually adopted for the manufacturing of the external surface of the wing leading edge since they are characterized by good mechanical properties at very high temperatures (up to 1900 °C) together with an excellent thermal shock resistance. Furthermore, the orthotropic behavior of these materials together with the possibility to tailor their lamination sequence to minimize the heat transferred to internal components, make them very attractive for hot structure based thermal protection systems applications. However, the numerical predictions of the thermo-mechanical behavior of such materials, taking into account the influence of each ply (whose thickness generally ranges between 0.2 and 0.3 mm), can be very expensive from a computational point of view. To overcome this limitation, usually, sub-models are adopted, able to focus on specific and critical areas of the structure where very detailed thermo-mechanical analyses can be performed without significantly affecting the computational efficiency of the global model. In the present work, sub-modeling numerical approaches have been adopted for the analysis of the thermo-mechanical behavior of a ceramic matrix composite wing leading edge of a hypersonic vehicle. The main aim is to investigate the feasibility, in terms of computational efficiency and accuracy of results, in using sub-models for dimensioning complex ceramic matrix components. Hence, a comprehensive study on the size of sub-models and on the choice of their boundaries has been carried out in order to assess the advantages and the limitations in approximating the thermo-mechanical behavior of the investigated global ceramic matrix composite component

Pancreatic tumors imaging: an update

Currently, ultrasound (US), computed tomography (CT) and Magnetic Resonance imaging (MRI) represent the mainstay in the evaluation of pancreatic solid and cystic tumors affecting pancreas in 80-85% and 10-15% of the cases respectively. Integration of US, CT or MR imaging is essential for an accurate assessment of pancreatic parenchyma, ducts and adjacent soft tissues in order to detect and to stage the tumor, to differentiate solid from cystic lesions and to establish an appropriate treatment. The purpose of this review is to provide an overview of pancreatic tumors and the role of imaging in their diagnosis and management. In order to a prompt and accurate diagnosis and appropriate management of pancreatic lesions, it is crucial for radiologists to know the key findings of the most frequent tumors of the pancreas and the current role of imaging modalities. A multimodality approach is often helpful. If multidetector-row CT (MDCT) is the preferred initial imaging modality in patients with clinical suspicion for pancreatic cancer, multiparametric MRI provides essential information for the detection and characterization of a wide variety of pancreatic lesions and can be used as a problem-solving tool at diagnosis and during follow-up

Il problema dell'interazione fluido-strutura nella modellazione del comportamento dinamico delle dighe

[IT] II problema in oggetto può essere formulato, come ben noto, a diversi livelli di complessità (e di “completezza” per quanto attiene alia rappresentatività física dei modelli proposti). Ciò è attestato dai numerosissimi contributi in proposito, a partire dal classico approccio “alla Westergaard” (v. concetto di “masse aggiunte”, Westergaard,1993) con fondo del serbatoio rígido (approccio nel quale, al livello più elementare, si assume anche I’ ipotesi di rigidità della struttura e di incomprimibilità del fluido), per arrivare alle formulazioni più recenti in cui si tiene conto, separatamente [8] o congiuntamente, della deformabilità della struttura, della comprimibilità del fluido e della deformabilità del fondo del serbatoio; formulazioni nelle quali in genere il concetto di “masse aggiunte” non è più valido (o va modificato profundamente, ad es. Rendendo tali “masse “ quantità complesse anzichè reali efunzioni della frequenza anzichè costanti). Assai spesso interessa in primo luogo identificare i modi naturali (smorzati o no) di vibrazione della diga, considerata come un sistema elástico lineare, ed in tal caso il problema è direttamente formulato in termini di oscillazioni armoniche (eventualmente con smorzamento: moto “pseudo-armonico”); la risposta ad eccilazioni non periodiche in campo lineare viene allora ricoslruita attraverso la nota tecnica dell’analisi modale.Fanelli, M.; Palumbo, P. (1998). Il problema dell'interazione fluido-strutura nella modellazione del comportamento dinamico delle dighe. Ingeniería del Agua. 5(2):51-62. https://doi.org/10.4995/ia.1998.2749SWORD516252Antes H., von Estorff, G., (1987) Analysis of absorption effects on the dynamic response of dam-reservoir systems by boundary element methods, Earthquake Eng. Str. Dyn. Vol. 15Fanelli M., (1990) Rapid preliminary analysis of arch dams: The Ritter method revisited, Dam Engineering. Vol.I, Issue 2Fanelli M., Fanelli A., (1992) Optimal proportioning of archgravity dams: the automatic generation of a simplified starting geometry, Dam Engineering. Vol.III, Issue 4Fanelli M, Fanelli A., Salvaneschi R, (1993) A neural network approach to the definition of near optimal arch dam shape, Dam Engineering, Vol. IV, Issue 2;Fanelli M., Fanelli A., Bonetti R, (1994) Non linear analysis in the preliminary evaluation of arch dam design, Hydropower & Dams. Vol.I, Issue 6Fanelli M., Fanelli A., GalimbertiC., Palumbo, P. (1995) The role of the reservoir in the selsmic analysis of concrete dams, Hydropower & Dams. Vol. 11, Issue 6Fork., Chopra A.K., (1986) Earthquake analysis of arch dams including dam-water interaction, boundary absorption and foundation flexibility, Earth-quake Eng. Str. Dyn. Vol. 14Kashiwayanagi M., Ohmachi T., (1992) Observed effects of reservoir water ondynamic characteristics of an arch dam, Proceedings. International Symposium on Arch Dams. Univ. Press, Nanjing, ChinaProceedings of the Benchmark-Workshops on Numerical Analysis of Dams: Bergamo, May 1991; Bergamo, July 1992; Paris, September 1994; Madrid, September 1996Westergaard, H.M., (1993) Water pressures on dams during earthquakes, Transactions of ASCE, Vol. 98, 41

Implementing virtual pheromones in BDI robots using MQTT and Jason

Robotic coordination is a crucial issue in the development of many applications in swarm robotics, ranging from mapping unknown and potentially dangerous areas to the synthesis of plans to achieve complex tasks such as moving goods between locations under resource constraints. In this context, stigmergy is a widely employed approach to robotic coordination based on the idea of interacting with the environment by means of markers called pheromones. Pheromones do not need to be "physical marks", and a number of works have investigated the use of digital, virtual pheromones. In this paper, we show how the concept of virtual pheromones can be implemented in Jason, a Java-based interpreter for an extended version of AgentSpeak, providing a high-level modelling and execution environment for multi-agent systems. We also exploit MQTT, a messaging infrastructure for the Internet-of-Things. This allows the implementation of stigmergic algorithms in a high-level declarative language, building on top of low-level infrastructures typically used only for controlling sensors and actuators

Sequeval: A framework to assess and benchmark sequence-based recommender systems

In this paper, we present sequeval, a software tool capable of performing the offline evaluation of a recommender system designed to suggest a sequence of items. A sequence-based recommender is trained considering the sequences already available in the system and its purpose is to generate a personalized sequence starting from an initial seed. This tool automatically evaluates the sequence-based recommender considering a comprehensive set of eight different metrics adapted to the sequential scenario. Sequeval has been developed following the best practices of software extensibility. For this reason, it is possible to easily integrate and evaluate novel recommendation techniques. Sequeval is publicly available as an open source tool and it aims to become a focal point for the community to assess sequence-based recommender systems

How the andrological sector suffered from the dramatic Covid 19 outbreak in Italy: supportive initiatives of the Italian Association of Andrology (SIA)

The possible strategies for the remodulation of the andrological activity were discussed and shared within a team of national experts belonging to the Italian Society of Andrology (SIA). Initiatives for andrologists. With the various provisions of the Prime Minister that have followed all the national and local scientific meetings were canceled. In order to compensate for this abrupt lack of opportunities for scientific meetings, a cycle of live reports was activated on YOUTUBE by recognized experts, to cover many different andrological topics. The YOUTUBE channel was chosen as it can be easily followed by each member without having to download any streaming program, with the possibility to consult the contents without any time limitation. Initiatives for patients In this new context, non-urgent outpatient activities (such as Andrology) have been suspended throughout the national territory

Is Italian Agriculture "Pull Factor" for Irregular Migration -- And, If So, Why?

In discussions on irregular migration in Europe, undeclared work is generally viewed as a "pull factor"—positive aspects of a destination-country that attract an individual or group to leave their home—for both employers as well as prospective migrants, and especially in sectors such as agriculture. A closer examination of the agricultural model, however, reveals that structural forces are driving demand for work and incentivizing exploitation. This is particularly evident in Southern Italy, a region famous for its produce, where both civil society organizations and the media have documented exploitation of migrant workers. A closer examination of EU and member states efforts to avoid exploitation is needed.In Is Italian Agriculture a 'Pull Factor' for Irregular Migration—and, If So, Why?, a new study, authors from the Open Society Foundations' European Policy Institute and the European University Institute look at how Europe's Common Agricultural Policy, the practices of supermarket chains, organized crime, and gang-master recruitment practices contribute to migrant exploitation. The study further recommends a closer examination of EU member state efforts to counter exploitation and offers an overview of private sector practice's intended to combat exploitation—such as the provision of information on workers' rights, adequate housing and transport, and EU-wide labeling schemes, among others

Synthesis of Tailored Perfluoro Unsaturated Monomers for Potential Applications in Proton Exchange Membrane Preparation

The aim of the present work is the synthesis and characterization of new perfluorinated monomers bearing, similarly to Nafion®, acidic groups for proton transport for potential and future applications in proton exchange membrane (PEM) fuel cells. To this end, we focused our attention on the synthesis of various molecules with (i) sufficient volatility to be used in vacuum polymerization techniques (e.g., PECVD)), (ii) sulfonic, phosphonic, or carboxylic acid functionalities for proton transport capacity of the resulting membrane, (iii) both aliphatic and aromatic perfluorinated tags to diversify the membrane polarity with respect to Nafion®, and (iv) a double bond to facilitate the polymerization under vacuum giving a preferential way for the chain growth of the polymer. A retrosynthetic approach persuaded us to attempt three main synthetic strategies: (a) organometallic Heck-type cross-coupling, (b) nucleophilic displacement, and (c) Wittig–Horner reaction (carbanion approach). Preliminary results on the plasma deposition of a polymeric film are also presented. The variation of plasma conditions allowed us to point out that the film prepared in the mildest settings (20 W) shows the maximum monomer retention in its structure. In this condition, plasma polymerization likely occurs mainly by rupture of the bond in the monomer molecule

Policy Brief: Is Italian Agriculture a "Pull Factor" for Irregular Migration -- And, If So, Why?

In discussions on irregular migration in Europe, undeclared work is generally viewed as a "pull factor"—positive aspects of a destination-country that attract an individual or group to leave their home—for both employers as well as prospective migrants, and especially in sectors such as agriculture. A closer examination of the agricultural model, however, reveals that structural forces are driving demand for work and incentivizing exploitation. This is particularly evident in Southern Italy, a region famous for its produce, where both civil society organizations and the media have documented exploitation of migrant workers. A closer examination of EU and member states efforts to avoid exploitation is needed.In Is Italian Agriculture a 'Pull Factor' for Irregular Migration—and, If So, Why?, a new study, authors from the Open Society Foundations' European Policy Institute and the European University Institute look at how Europe's Common Agricultural Policy, the practices of supermarket chains, organized crime, and gang-master recruitment practices contribute to migrant exploitation. The study further recommends a closer examination of EU member state efforts to counter exploitation and offers an overview of private sector practice's intended to combat exploitation—such as the provision of information on workers' rights, adequate housing and transport, and EU-wide labeling schemes, among others

BC-SIM-IAPSUPA-TR-001 HRIC NECP report

The present document has been issued with the aim of describing the NECP (Near Earth Commissioning Phase) Tests results of HRIC channel part of the SIMBIO-SYS instrument suite on board the BepiColombo ESA mission