Drag reduction of cylinders by partial porous coating

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The paper summarizes experimental investigations concerning drag reduction of circular cylinders by porous coating. In order to quantify the effect, wind tunnel experiments with a force balance and flow field analyses have been carried out. In a first experiment, the cylinders were coated completely with a thin porous layer. The results show that the boundary layer over the porous surface is turbulent right from the beginning and thickens faster because of the enhanced vertical momentum exchange when compared to a smooth cylinder surface. The region of flow detachment is widened resulting in a broader area with almost vanishing low flow velocities. All in all, the measurements show that a full porous coating of the cylinders increase the flow resistance. In a second experiment, the cylinders were coated only on the leeward side, which resulted in a reduction of the body's flow resistance. This effect seems due to the fact that the recirculating velocity and the underpressure in the wake is reduced significantly through a leeward porous coating. Thus, combining a smooth non-permeable windward side with a porously coated leeward side can lead to a drag reduction of the body. These findings can be applied advantageously in many technical areas, such as energy saving of moving bodies (cars/trains/planes) or in reducing fluid loads on submersed bodies.dc201

Quality of life in elderly ICU survivors before the COVID-19 pandemic: a systematic review and meta-analysis of cohort studies

Objectives The influence of age on intensive care unit (ICU) decision-making is complex, and it is unclear if it is based on expected subjective or objective patient outcomes. To address recent concerns over age-based ICU decision-making, we explored patient-assessed quality of life (QoL) in ICU survivors before the COVID-19 pandemic. Design A systematic review and meta-analysis of cohort studies published between January 2000 and April 2020, of elderly patients admitted to ICUs. Primary and secondary outcome measures We extracted data on self-reported QoL (EQ-5D composite score), demographic and clinical variables. Using a random-effect meta-analysis, we then compared QoL scores at follow-up to scores either before admission, age-matched population controls or younger ICU survivors. We conducted sensitivity analyses to study heterogeneity and bias and a qualitative synthesis of subscores. Results We identified 2536 studies and included 22 for qualitative synthesis and 18 for meta-analysis (n=2326 elderly survivors). Elderly survivors’ QoL was significantly worse than younger ICU survivors, with a small-to- medium effect size (d=0.35 (−0.53 and −0.16)). Elderly survivors’ QoL was also significantly greater when measured slightly before ICU, compared with follow-up, with a small effect size (d=0.26 (−0.44 and −0.08)). Finally, their QoL was also marginally significantly worse than age-matched community controls, also with a small effect size (d=0.21 (−0.43 and 0.00)). Mortality rates and length of follow-up partly explained heterogeneity. Reductions in QoL seemed primarily due to physical health, rather than mental health items. Conclusions The results suggest that the proportionality of age as a determinant of ICU resource allocation should be kept under close review and that subjective QoL outcomes should inform person-centred decision -aking in elderly ICU patients. PROSPERO registration number CRD42020181181

How Captain Amerika uses neural networks to fight crime

Artificial neural network models can make amazing computations. These models are explained along with their application in problems associated with fighting crime. Specific problems addressed are identification of people using face recognition, speaker identification, and fingerprint and handwriting analysis (biometric authentication)

What determines the differences found in forest edge flow between physical models and atmospheric measurements? - An les study

A recent study has shown that Doppler lidar is a state-of-the-art method to obtain spatially and temporally resolved flow fields in forest edge flow regimes. In that study, the general flow features observed by lidar were found to be similar to those detected above a physical tree model in a wind tunnel. But in pivotal details, for example regarding the absolute height and the inner structure of the internal boundary layer (IBL), significant differences were detected. The main objectives of this Large-Eddy Simulation (LES) study are to analyze these differences and to associate them to the meteorological and physical differences between the set-ups of the wind tunnel and the atmospheric measurement. This enables on the one hand a model evaluation for the LES and the physical model respectively, and on the other hand a better understanding of the results from the lidar measurements. Results from an LES with neutral stratification and without Coriolis force show a similar IBL structure as in the wind tunnel and represent well-known characteristics of forest edge flow. A variation of the forest density only marginally affects the IBL structure. The presence of a finite forest clearing as observed at the lidar site increases the turbulence level of the IBL, compared to a set-up with a quasi-infinite clearing like in the wind tunnel. Including Coriolis force further enhances the turbulence levels to values observed by lidar. An increasing thermal instability results in even higher turbulence levels. Hence, differences between wind tunnel and atmospheric measurements are mainly traced back to differences in the flow forcing and in the onflow conditions upstream of the forest edge. Furthermore, a statistical analysis reveals that insufficient averaging of the lidar data also contributes to the observed deviations from the wind tunnel results. Based on this analysis, we suggest that at least two and a half hours of measurements during equivalent atmospheric conditions are necessary to obtain a statistically representative mean IBL structure

International Educators’ Perspectives on the Purpose of Science Education and the Relationship between School Science and Creativity

This is the author accepted manuscript. The final version is available from Taylor & Francis (Routledge) via the DOI in this record.Background: Creativity across all disciplines is increasingly viewed as a fundamental educational capability. Science can play a potentially important role in the nurturing of creativity. Research also suggests that creative pedagogy, including interdisciplinary teaching with Science and the Arts, can engage students with science. Previous studies into teachers’ attitudes to the relationship between science and creativity have been largely situated within national educational contexts. Purpose: This study, part of the large EU funded CREATIONs project, explores educators’ perspectives on the relationship between Science and Creativity across national contexts drawn from Europe and beyond. Sample and Methods: 270 educators, broadly defined to include primary (age 4-11) and secondary (age 11-18) teachers and trainee teachers, informal educators and teacher educators, responded to a survey designed to explore perceptions of the relationship between science and creativity. Respondents were a convenience sample recruited by project partners and through online media. The elements of the survey reported here included Likert-scale questions, open response questions, and ranking questions in the form of an electronic self-administered questionnaire. Exploratory factor analysis was used to develop a combined attitude scale labelled ‘science is creative’, with results compared across nationalities and phases of education. Open question responses were analysed thematically to allow more nuanced interpretation of the descriptive statistical findings. Results: The findings show broad agreement internationally and across phases that science is a creative endeavour, with a small number of educators disagreeing about the 3 relationship between science and creativity in the context of school science. Those who disagreed were usually secondary science teachers, from England, Malta or outside Europe (primarily from the United States). The role of scientific knowledge within creativity in science education was found to be contentious. Conclusions: That educators broadly see science as creative is unsurprising, but initial exploration of educators’ perspectives internationally shows some areas of difference. These were especially apparent for educators working in formal education, particularly relating to the role of knowledge with respect to creativity in science. With current interest in STEAM education, further investigation to understand potential mediating factors of national educational contexts on teachers’ perspectives with respect to the role of disciplinary knowledge(s) in creativity and their interaction in interdisciplinary teaching and learning, is recommended.European Commissio

Creative pedagogy and environmental responsibility: A diffractive analysis of an intra-active science|arts practice

This is the author accepted manuscriptThis chapter explores the entanglement of research and practice, offering an account of science|arts practice in which research-driven “features of creative pedagogy” were used within an action research project to engage young people with the problem of ocean plastics. Thinking with Barad’s theory of agential realism, we explore the ongoing emergence of new matter and meaning for the young people, teachers and researchers engaged in this transdisciplinary practice-research. One component of a large H2020-funded project exploring creativity in science/arts transdisciplinary practices across Europe was a study of action research in six UK secondary schools with science/art teacher pairs. This chapter draws on research conducted within one school in which the issue of plastics in the ocean was explored with 52 students aged 14–15 within an “arts-science project”, to develop the young people’s ideas about environmental responsibility understood, explored and expressed together through science and art. An approach to researching emergent and creative pedagogies which brings agency to the fore within a material-dialogic, intra-active understanding of (post)human creativity was used. Data gathered through mixed methods, including questionnaires, interviews and photographs, and selected via “glow moment” assemblages, were analysed with and through theory using diffractive analysis to iteratively unfold data, theory, research and practice. This stance embodies a material-dialogic approach, with research, theory and “data” in dialogue. In the chapter, a sequence of diffractions is described, responding to initial questions posed by the book editors: “When/where/how do objects/subjects of inquiry, and embodiment, come to matter in STEAM (re-)configurings in practice?” These diffractions unfold the emergence of matter and meaning through intra-active material dialogue in a science|art practice, raising questions from/for practice about the concept of ethics, trusteeship and responsibility in environmental education.European Commissio

Cu-O network-dependent core-hole screening in low-dimensional cuprate systems: a high-resolution X-ray photoemission study

We present an experimental study of the dynamics of holes in the valence bands of zero-, one-, and two-dimensional undoped model cuprates, as expressed via the screening of a Cu 2p core hole. The response depends strongly upon the dimensionality and the details of the Cu-O-Cu network geometry and clearly goes beyond the present theoretical state-of-the-art description within the three-band d-p model

Simonsenia aveniformis sp nov (Bacillariophyceae), molecular phylogeny and systematics of the genus, and a new type of canal raphe system

The genus Simonsenia is reviewed and S. aveniformis described as new for science by light and electron microscopy. The new species originated from estuarine environments in southern Iberia (Atlantic coast) and was isolated into culture. In LM, Simonsenia resembles Nitzschia, with bridges (fibulae) beneath the raphe, which is marginal. It is only electron microscope (EM) examination that reveals the true structure of the raphe system, which consists of a raphe canal raised on a keel (wing), supported by rib like braces (fenestral bars) and tube-like portulae; between the portulae the keel is perforated by open windows (fenestrae). Based on the presence of portulae and a fenestrated keel, Simonsenia has been proposed to be intermediate between Bacillariaceae and Surirellaceae. However, an rbcL phylogeny revealed that Simonsenia belongs firmly in the Bacillariaceae, with which it shares a similar chloroplast arrangement, rather than in the Surirellaceae. Lack of homology between the surirelloid and simonsenioid keels is reflected in subtle differences in the morphology and ontogeny of the portulae and fenestrae. The diversity of Simonsenia has probably been underestimated, particularly in the marine environment.Polish National Science Centre in Cracow within the Maestro program [N 2012/04/A/ST10/00544]; Sciences and Technologies Foundation-FCT (Portugal) [SFRH/BD/62405/2009]info:eu-repo/semantics/publishedVersio