High-Voltage Temperature Humidity Bias Test (HV-THB): Overview of Current Test Methodologies and Reliability Performances

2The high voltage temperature humidity bias test (HV-THB) has become increasingly popular for evaluating the performances of power semiconductor devices. Given the new challenges of the power semiconductor industry, several applications and devices need to be designed to withstand harsh environments during working operations, with a remarkable focus on high-humidity conditions. The HV-THB test allows one to activate and study different failure mechanisms which were not highlighted by the standard low voltage THB test, enabling new designs in several energy conversion fields, such as energy harvesting, industry and automotive applications. After a brief introduction of current test standards, this work goes through the current methodologies and state-of-the-art of the HV-THB test. The following sections are then dedicated to the knowledge about the failure mechanisms and the models for accelerated testing. Eventually, there is a section devoted to the main passivation materials in order to understand their effects on the HV-THB capabilities of the devices.openopenDavide Cimmino; Sergio FerreroCimmino, Davide; Ferrero, Sergi

Methane-Assisted Iron Oxides Chemical Looping in a Solar Concentrator: A Real Case Study

Recent interest in hydrogen as an alternative fuel for lowering carbon emissions is funding the exploration of new ways to cleanly produce this molecule. Iron oxides can be used within a process of chemical looping. More specifically, they can lose oxygens at extremely high temperature in an inert atmosphere. An alumina receiver could not stand the extreme thermal stress, while steel (AISI 316 and Inconel Hastelloy c-276) lasted enough for the reaction to start, even if at the end of the process the receiver melted. Operating at a temperature above 1000 K helped the reaction switch from methane chemical looping combustion to chemical looping reforming, thus favouring H2 and CO yields. The gas flow outlet from the reactor reached a percentage up to 45% of H2 and 10% of CO. Carbon dioxide instead reached very low concentrations. While CO and CO2 reached a peak at the beginning of the experiment and then decreased, H2 was oscillating around a stable value. Unreacted methane was detected. The temperatures recorded in the reactor and the gas mixture obtained were used to validate a multiphysical model. The heat transfer and the chemistry of the experiment were simulated

Riding, Filming and Posting: Digital Ways to Skateboarding Professional Authenticity in Italy

Skaters have always been involved in making their practice visible and recordable to become professional athletes through gaining sponsorship from corporations, meanwhile struggling to keep subcultural recognition within the peer community. New media are providing amateurs and professional skaters with a variety of more accessible digital media-based careers.In this article, drawing on a qualitative research project carried out in 2014-15, including participant observation, digital ethnography and interviews with skaters in the peripheral skate context of Turin, Northern Italy, we will focus on the ways three profiles of skate-involved professionals (skate-shop managers; sponsored amateurs; and filmers) use new media. New media on the one hand facilitate the access to the main sponsorship scheme career; on the other hand, alternative uses of new technologies (e.g., opting for low-quality filming or displaying creative, ground-level tricks) open up new battlegrounds for claiming subcultural authenticity, reshaping distinctions and hierarchies within different skate professional careers

Managing alternative sports: new organisational spaces for the diffusion of Italian parkour

The article explores the encounter between parkour as an unstructured and culturally innovative practice, challenging both physical as well as organisational spaces, and UISP (Unione Italiana Sport per Tutti / Sport for All Italian Union) as a sport promotion body open to organisational and cultural experimentation. Drawing on a multi-method qualitative approach (analysis of documentary material, interviews and focus groups), we look at the role of UISP in the diffusion and legitimation of parkour within the Italian context, investigating the interplay between the cultural and organisational logics of both this new practice itself on the one hand, and the organisations that are trying to accommodate it on the other. The incorporation in a sport-for-all organisation like UISP provides traceurs with a safe and legitimised space, which is however ‘loose’ enough to maintain the fluidity of the practice. Nonetheless, by enabling the coexistence of different and competing definitions and uses of parkour, this fluid organisational space reproduces tensions among traceurs and weakens their voice in UISP’s decision-making processes

The RES approach for debris flow susceptibility analysis: A case study

Climate change has increased the occurrence and magnitude of debris flow events, especially in mountain areas. Moreover, their unpredictability requires to develop reliable methodologies for the evaluation of debris flow susceptibility, which is the starting point for risk assessment and management. In this paper, a modified version of the Debris flow Propensity Index (DfPI) is developed for the debris flow susceptibility estimation at basin scale. Bedrock lithology, fracture network, quaternary deposits, slope angle, channel network, and land use were identified as debris flow predisposing factors and were indexed by using open-access data and geodatabases. The objective of the proposed study is to develop a simple and economic procedure for the susceptibility estimation, easily to implement in GIS-based software for further analyses, such as propagation simulations or hazard scenarios, useful for planning mitigation strategies. The Can? Valley, a small valley located in the more famous Camonica Valley, (Lombardia Region, Northern Italy), was used as a case study for developing and testing the proposed approach

Pyogenic Granuloma of the Sigmoid Colon causing Intussusception in an Infant

Pyogenic granuloma is a benign vascular tumor that may affect the gastrointestinal tract. This report describes a rare case of sigmoid-colon pyogenic granuloma in a 4-month-old boy causing intussusception. Resection and anastomosis were curative. The mother had history of high dose of progesterone exposure during initial weeks of conception for vaginal bleeding. This may point towards etiology of the lesion