Graded Readers and Vocabulary

No description supplie

Contact analysis using Trefftz and interface finite elements

Hybrid-Trefftz (HT) finite element (FE) analysis of two-dimensional elastic contact problems is addressed with the aid of interface elements and an interfacial constitutive relation. This paper presents the formulation of a four-noded HT finite element for discretizing the contacting bodies and a four-noded interface element that could be embedded in the prospective contact zone for simulating the interaction behaviour. Due to the superior performance, the Simpson-type Newton-Cotes integration scheme is utilized to compute interface element formulation numerically. In order to evaluate the applicability of the present approach two benchmark examples are investigated in detail. Comparisons have been made between the results by the present approach and analytical as well as traditional FE solutions using ABAQUS software

Contact modelling using Trefftz and interface finite elements

Modelling of elastic contact problems is addressed with the aid of Hybrid-Trefftz (HT) and interface finite elements based on a simple interfacial constitutive relation. This paper presents the formulation of a four-noded HT finite element for discretizing the contacting bodies and a four-noded interface element that could be embedded in the prospective contact zone for simulating the interaction behaviour. Due to the superior performance, the Simpson-type Newton-Cotes integration scheme is utilized to compute interface element formulation numerically. In order to evaluate the applicability of the present approach two benchmark examples are investigated in detail. Comparisons have been made between the results by the present approach and analytical as well as traditional FE solutions using ABAQUS software

Antibiotics for lower respiratory tract infection in children presenting in primary care: ARTIC-PC RCT

Background Antimicrobial resistance is a global health threat. Antibiotics are commonly prescribed for children with uncomplicated lower respiratory tract infections, but there is little randomised evidence to support the effectiveness of antibiotics in treating these infections, either overall or relating to key clinical subgroups in which antibiotic prescribing is common (chest signs; fever; physician rating of unwell; sputum/rattly chest; shortness of breath). Objectives To estimate the clinical effectiveness and cost-effectiveness of amoxicillin for uncomplicated lower respiratory tract infections in children both overall and in clinical subgroups. Design Placebo-controlled trial with qualitative, observational and cost-effectiveness studies. Setting UK general practices. Participants Children aged 1–12 years with acute uncomplicated lower respiratory tract infections. Outcomes The primary outcome was the duration in days of symptoms rated moderately bad or worse (measured using a validated diary). Secondary outcomes were symptom severity on days 2–4 (0 = no problem to 6 = as bad as it could be); symptom duration until very little/no problem; reconsultations for new or worsening symptoms; complications; side effects; and resource use. Methods Children were randomised to receive 50 mg/kg/day of oral amoxicillin in divided doses for 7 days, or placebo using pre-prepared packs, using computer-generated random numbers by an independent statistician. Children who were not randomised could participate in a parallel observational study. Semistructured telephone interviews explored the views of 16 parents and 14 clinicians, and the data were analysed using thematic analysis. Throat swabs were analysed using multiplex polymerase chain reaction. Results A total of 432 children were randomised (antibiotics, n = 221; placebo, n = 211). The primary analysis imputed missing data for 115 children. The duration of moderately bad symptoms was similar in the antibiotic and placebo groups overall (median of 5 and 6 days, respectively; hazard ratio 1.13, 95% confidence interval 0.90 to 1.42), with similar results for subgroups, and when including antibiotic prescription data from the 326 children in the observational study. Reconsultations for new or worsening symptoms (29.7% and 38.2%, respectively; risk ratio 0.80, 95% confidence interval 0.58 to 1.05), illness progression requiring hospital assessment or admission (2.4% vs. 2.0%) and side effects (38% vs. 34%) were similar in the two groups. Complete-case (n = 317) and per-protocol (n = 185) analyses were similar, and the presence of bacteria did not mediate antibiotic effectiveness. NHS costs per child were slightly higher (antibiotics, £29; placebo, £26), with no difference in non-NHS costs (antibiotics, £33; placebo, £33). A model predicting complications (with seven variables: baseline severity, difference in respiratory rate from normal for age, duration of prior illness, oxygen saturation, sputum/rattly chest, passing urine less often, and diarrhoea) had good discrimination (bootstrapped area under the receiver operator curve 0.83) and calibration. Parents found it difficult to interpret symptoms and signs, used the sounds of the child’s cough to judge the severity of illness, and commonly consulted to receive a clinical examination and reassurance. Parents acknowledged that antibiotics should be used only when ‘necessary’, and clinicians noted a reduction in parents’ expectations for antibiotics. Limitations The study was underpowered to detect small benefits in key subgroups. Conclusion Amoxicillin for uncomplicated lower respiratory tract infections in children is unlikely to be clinically effective or to reduce health or societal costs. Parents need better access to information, as well as clear communication about the self-management of their child’s illness and safety-netting. Future work The data can be incorporated in the Cochrane review and individual patient data meta-analysis.</p

Roadmap on nanogenerators and piezotronics

Piezoelectric nanogenerator (PENG) was first introduced by using piezoelectric nanowires for converting tiny mechanical energy into electric power. Research in nanogenerators has been vastly expanded in the last decade due to the invention of the triboelectric nanogenerator (TENG). As of today, the definition of nanogenerator has far exceeded its traditional meaning, and it represents a field that uses the Maxwell’s displacement current to convert mechanical energy into electric power/signal. This field is attracting a wide range of interest due to the huge advances in the internet of things, big data, sensor network, robotics, and artificial intelligence. TENGs are playing a key role in harvesting high entropy energy distributed in our living environment for effective driving of distributed electronics and systems.</p

SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution - survey description and compact source catalogue

We present the first release of the data and compact-source catalogue for the JCMT Large Program SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE). SCOPE consists of 850 μm continuum observations of 1235 Planck Galactic Cold Clumps (PGCCs) made with the Submillimetre Common-User Bolometer Array 2 on the James Clerk Maxwell Telescope. These data are at an angular resolution of 14.4 arcsec, significantly improving upon the 353 GHz resolution of Planck at 5 arcmin, and allowing for a catalogue of 3528 compact sources in 558 PGCCs. We find that the detected PGCCs have significant sub-structure, with 61 per cent of detected PGCCs having three or more compact sources, with filamentary structure also prevalent within the sample. A detection rate of 45 per cent is found across the survey, which is 95 per cent complete to Planck column densities of N(H2) > 5 × 10^21 cm^−2. By positionally associating the SCOPE compact sources with young stellar objects, the star formation efficiency, as measured by the ratio of luminosity to mass, in nearby clouds is found to be similar to that in the more distant Galactic Plane, with the column density distributions also indistinguishable from each other