Insights into building a digital twin of closed-cell aluminum foam during impact loading: Microstructural, experimental and finite element investigations

The mechanical behavior of metal foams under impact loading depends on multiple and complex parameters like impact velocity, strain-rate, local plastic deformation, oscillating and micro-inertial effects, etc. The prediction of the behavior of metal foams that are subject to impact loads is still challenging and engineering application of these materials typically requires time-consuming experimental tests. Numerical models based on the finite element method (FEM) can contribute to minimizing the experimentation effort. Realistic FEM models were built that account both for the macro- and micro-scopic characteristics of the porous material, explain the acting mechanisms that take place during impact, and study the yield properties as well as the energy absorption during the impact of closed-cell aluminum foams. The simulation results are compared with the ones derived from respective experimental uniaxial tests. Two different modeling approaches were applied thus creating two models. The first model relies on a cell-based method where the initial geometry of the foam was generated based on the Voronoi tessellation algorithm and the second one relies on the isotropic, strain-hardening, and continuum-based model developed by Deshpande-Fleck. The outcome of the investigation sheds light on the metal foam behavior under impact by explaining macro- and micro-structural phenomena that develop during impact

“Out there”: British travel journalism and the negotiation of cultural difference

This chapter examines how British travel journalism provides its readership with cultural frames of reference for a specific touristic experience: safari holidays in Africa. It will focus on a selection of articles from British broadsheet newspapers, from The Sunday Times, and The Sunday Telegraph. The intention is to address two principal concerns. What representational strategies are deployed in travel journalism on this region and how are they constitutive of broader British imaginings of Africa? Secondly, it is important that these representational concerns are considered in terms of the commercial context in which they are produced. In addressing these concerns the intention is also to explore how this is indicative of the broader, cultural frames of reference through which travel journalism views its “others”

COVID-19 in children and adolescents in Europe: a multinational, multicentre cohort study

Background To date, few data on paediatric COVID-19 have been published, and most reports originate from China. This study aimed to capture key data on children and adolescents with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection across Europe to inform physicians and health-care service planning during the ongoing pandemic. Methods This multicentre cohort study involved 82 participating health-care institutions across 25 European countries, using a well established research network—the Paediatric Tuberculosis Network European Trials Group (ptbnet)—that mainly comprises paediatric infectious diseases specialists and paediatric pulmonologists. We included all individuals aged 18 years or younger with confirmed SARS-CoV-2 infection, detected at any anatomical site by RT-PCR, between April 1 and April 24, 2020, during the initial peak of the European COVID-19 pandemic. We explored factors associated with need for intensive care unit (ICU) admission and initiation of drug treatment for COVID-19 using univariable analysis, and applied multivariable logistic regression with backwards stepwise analysis to further explore those factors significantly associated with ICU admission. Findings 582 individuals with PCR-confirmed SARS-CoV-2 infection were included, with a median age of 5·0 years (IQR 0·5–12·0) and a sex ratio of 1·15 males per female. 145 (25%) had pre-existing medical conditions. 363 (62%) individuals were admitted to hospital. 48 (8%) individuals required ICU admission, 25 (4%) mechanical ventilation (median duration 7 days, IQR 2–11, range 1–34), 19 (3%) inotropic support, and one (<1%) extracorporeal membrane oxygenation. Significant risk factors for requiring ICU admission in multivariable analyses were being younger than 1 month (odds ratio 5·06, 95% CI 1·72–14·87; p=0·0035), male sex (2·12, 1·06–4·21; p=0·033), pre-existing medical conditions (3·27, 1·67–6·42; p=0·0015), and presence of lower respiratory tract infection signs or symptoms at presentation (10·46, 5·16–21·23; p<0·0001). The most frequently used drug with antiviral activity was hydroxychloroquine (40 [7%] patients), followed by remdesivir (17 [3%] patients), lopinavir–ritonavir (six [1%] patients), and oseltamivir (three [1%] patients). Immunomodulatory medication used included corticosteroids (22 [4%] patients), intravenous immunoglobulin (seven [1%] patients), tocilizumab (four [1%] patients), anakinra (three [1%] patients), and siltuximab (one [<1%] patient). Four children died (case-fatality rate 0·69%, 95% CI 0·20–1·82); at study end, the remaining 578 were alive and only 25 (4%) were still symptomatic or requiring respiratory support. Interpretation COVID-19 is generally a mild disease in children, including infants. However, a small proportion develop severe disease requiring ICU admission and prolonged ventilation, although fatal outcome is overall rare. The data also reflect the current uncertainties regarding specific treatment options, highlighting that additional data on antiviral and immunomodulatory drugs are urgently needed