Single pulse avalanche robustness and repetitive stress ageing of SiC power MOSFETs

This paper presents an extensive electro-thermal characterisation of latest generation silicon carbide (SiC) Power MOSFETs under unclamped inductive switching (UIS) conditions. Tests are carried out to thoroughly understand the single pulse avalanche ruggedness limits of commercial SiC MOSFETs and assess their aging under repetitive stress conditions. Both a functional and a structural characterisation of the transistors is presented, with the aim of informing future device technology development for robust and reliable power system development

Seismic Vulnerability Assessment of a Historical Church: Limit Analysis and Nonlinear Finite Element Analysis

The seismic vulnerability of a historical Basilica church located in Italy is studied by means of limit analysis and nonlinear finite element (FE) analysis. Attention is posed to the failure mechanisms involving the façade of the church and its interaction with the lateral walls. In particular, the limit analysis and the nonlinear FE analysis provide an estimate of the load collapse multiplier of the failure mechanisms. Results obtained from both approaches are in agreement and can support the selection of possible retrofitting measures to decrease the vulnerability of the church under seismic loads

Design tools for rapid multidomain prototyping of power electronic systems

The need for multidisciplinary virtual prototyping in power electronics has been well established however design tools capable of facilitating a rapid, iterative virtual design process do not exist. A key challenge in developing such tools is identifying and developing modelling techniques which can account for 3D, geometrical design choices without unduly affecting simulation speed. This challenge has been addressed in this work using model order reduction techniques and a prototype power electronic design tool incorporating these techniques is presented. A relevant electro-thermal power module design example is then used to demonstrate the performance of the software and model order reduction techniques. Five design iterations can be evaluated, using 3D inductive and thermal models, under typical operating and startup conditions on a desktop PC in less than 15 minutes. The results are validated experimentally for both thermal and electrical domains

A Method for Battery Sizing in Parallel P4 Mild Hybrid Electric Vehicles

This article deals with a sensitivity analysis concerning the influence that the capacity of the battery in a parallel hybrid powertrain has on the vehicle's energy regeneration. The architecture under analysis is constituted by an internal combustion engine (ICE), which provides traction to the front axle's wheels, and an electric motor powering the rear wheels. The energy management system (EMS) is based on a simple torque split strategy that distributes the driver's required torque between the front and rear machines as a function of battery and electric motor functional limitations (state of charge, temperatures, and maximum admissible currents). Together with the selected driving cycles, the central role played by the battery size in the overall vehicle recoverable energy is evaluated, while the influence of the powertrain limitations is highlighted, accounting both for uncertain parameters (e.g., initial state of charge [SoC 0]) and for tunable parameters (e.g., maximum electric traction vehicle speed). Therefore, a method of sizing the battery of a P4 mild hybrid electric vehicle (HEV), which allows the maximization of the braking energy recovery, is developed

Students’ experiences of learning in the operating theatre

Human parechoviruses (HPeVs) are members of the large and growing family of Picornaviridae. Although 16 types have been described on the basis of the phylogenetic analyses of the VP1 encoding region, the majority of published reports relate to the HPeV types 1-8. In pediatrics, HPeV1, HPeV2 and HPeV4-8 mainly cause mild gastrointestinal or respiratory illness; only occasionally more serious diseases have been reported, including myocarditis, encephalitis, pneumonia, meningitis, flaccid paralysis, Reye syndrome and fatal neonatal infection. In contrast, HPeV3 causes severe illness in young infants, including sepsis and conditions involving the central nervous system. Currently, the most sensitive method for detecting HPeV is real-time polymerase chain reaction assays on stools, respiratory swabs, blood and cerebrospinal fluid. However, although it is known that HPeVs play a significant role in various severe pediatric infectious diseases, diagnostic assays are not routinely available in clinical practice and the involvement of HPeV is therefore substantially underestimated. Despite long-term efforts, the development of antiviral therapy against HPeVs is limited; no antiviral medication is available and the use of monoclonal antibodies is still being evaluated. More research is therefore needed to clarify the specific characteristics of this relevant group of viruses and to develop appropriate treatment strategies

SiC power MOSFETs performance, robustness and technology maturity

Relatively recently, SiC power MOSFETs have transitioned from being a research exercise to becoming an industrial reality. The potential benefits that can be drawn from this technology in the electrical energy conversion domain have been amply discussed and partly demonstrated. Before their widespread use in the field, the transistors need to be thoroughly investigated and later validated for robustness and longer term stability and reliability. This paper proposes a review of commercial SiC power MOSFETs state-of-the-art characteristics and discusses trends and needs for further technology improvements, as well as device design and engineering advancements to meet the increasing demands of power electronics

A computational multiscale approach to couple hygro-mechanical responses of large-scale masonry walls

We present a computational multiscale approach to the nonlinear problems of humidity diffusion and mechanical damage of large-scale masonry walls, and their coupling in terms of the effects of the humidity diffusion on the mechanical response and the effects of the mechanical degradation on the diffusion process. Such an approach allows us to recover, both efficiently and accurately, the complex nonlinear response of large-scale walls, which are in general hard to be solved by means of standard numerical tools. Two representative tests of two- and three-storey walls are here analyzed, and the corresponding results reported and commented, aiming to show how samples like these can potentially serve as reference solutions for more applicative purposes

Update on the management of pediatric acute osteomyelitis and septic arthritis

Acute osteomyelitis and septic arthritis are two infections whose frequencies are increasing in pediatric patients. Acute osteomyelitis and septic arthritis need to be carefully assessed, diagnosed, and treated to avoid devastating sequelae. Traditionally, the treatment of acute osteoarticular infection in pediatrics was based on prolonged intravenous anti-infective therapy. However, results from clinical trials have suggested that in uncomplicated cases, a short course of a few days of parenteral antibiotics followed by oral therapy is safe and effective. The aim of this review is to provide clinicians an update on recent controversies and advances regarding the management of acute osteomyelitis and septic arthritis in children. In recent years, the emergence of bacterial species resistant to commonly used antibiotics that are particularly aggressive highlights the necessity for further research to optimize treatment approaches and to develop new molecules able to fight the war against acute osteoarticular infection in pediatric patients

Effect of a multistrain probiotic (Lactoflorene® Plus) on inflammatory parameters and microbiota composition in subjects with stress-related symptoms

Stress affects the immune system and intestinal microbiota composition and can lead to imbalance between pro- and anti-inflammatory cytokines or to uncontrolled production of cytokines. The effect of emotional stress on secretory IgA levels also indicates that stress decreases mucosal integrity. Our aim was to evaluate whether a probiotic product (Lactoflorene® Plus) can prevent alterations in the immune response associated with self-reported stress and microbiota composition. Healthy adult volunteers who self-reported psychological stress were enrolled and randomised into a placebo and a probiotic group. Salivary stress markers (α-amylase, cortisol, chromogranin A) and immunological parameters (sIgA, NK cell activity, IL-8, IL-10, TNF-α) in feces and the composition of intestinal microbiota were evaluated. Administration of the product did not exert a direct effect on the salivary stress markers or NK cell activity but did reduce abdominal pain and increase faecal IgA and IL-10 levels. The probiotic product induced a moderate increase in Bifidobacterium and Lactobacillus spp., as expected, and in Faecalibacterium spp., and decreased the size of the Dialister spp. and Escherichia and Shigella populations. Administration of the product helped protect the mucosal barrier by supporting the number of short-chain fatty acid producers and decreasing the load of potentially harmful bacteria, thus reducing intestinal inflammation and abdominal discomfort. ClinicalTrials.gov: NCT03234452

Semi-automated creation of accurate FEM meshes of heritage masonry walls from point cloud data

The structural analysis of buildings requires accurate spatial models. Additionally, pathologies such as settlement-induced damages are paramount in the assessment of heritage assets. This spatial information is used as a basis for Finite Element Method (FEM) meshes to evaluate the stability of the structure. Traditional data acquisition approaches rely on manual measurements which are labor intensive and error prone. Therefore, major simplifications are made to document structures efficiently. The goal of this research is to provide faster and more accurate procedures to capture the spatial information required by a FEM. This paper presents a semi-automated approach to create accurate models of complex heritage buildings for the purpose of structural analysis. By employing non-destructive techniques such as terrestrial laser scanning and photogrammetry, a complex mesh of the structure is created. Also, a methodology is proposed to capture crack information. A stepwise approach is elaborated to illustrate how the spatial information is adapted towards a FEM mesh. The results show a significant difference between the geometry our model and a traditional wire- frame model. Not only does accurate modelling result in deviating loads, it also affects the behavior of the object. Through the proposed approach, experts can develop highly accurate FEM meshes to assess the stability of the structure up to as-built conditionsPostprint (published version