1,878 research outputs found

    The standing wave model of the mesons and baryons

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    Only photons are needed to explain the masses of the pi(0), eta, Lambda, Sigma(0), Xi(0), Omega(-), Lambda(c,+), Sigma(c,0), Xi(c,0), and Omega(c,0) mesons and baryons. Only neutrinos are needed to explain the mass of the pi(+-) mesons. Neutrinos and photons are needed to explain the masses of the K-mesons, the neutron and D-mesons. Surprisingly the mass of the mu-meson can also be explained by the oscillation energies and rest masses of a neutrino lattice. From the difference of the masses of the pi(+-) mesons and mu(+-) mesons follows that the rest mass of the muon-neutrino is 47.5 milli-eV. From the difference of the masses of the neutron and proton follows that the rest mass of the electron-neutrino is 0.55 milli-eV. The potential of the weak force that holds the lattices of the particles together can be determined with Born's lattice theory. From the weak force follows automatically the existence of a strong force between the sides of two lattices. The strong nuclear force is the sum of the unsaturated weak forces at the sides of each lattice and is therefore 10^6 times stronger than the weak force.Comment: 41 pages, 6 figure

    Albedo and laser threshold of a diffusive Raman gain medium

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    The diffuse reflectance (albedo) and transmittance of a Raman random gain medium are calculated via semi-analytic two-stream equations with power-dependent coefficients. The results show good agreement with the experimental data for barium nitrate powder. Both the Raman albedo AR and Raman transmittance TR diverge at a critical gain gc, interpreted as the threshold for diffusive Raman laser generation. However, the ratio TR/AR approaches a finite limiting value dependent on particle scattering albedo v and scattering asymmetry g. The dependence of the generation threshold on the scattering parameters is analysed and the feedback effect of Fresnel reflection at the gain boundaries evaluated. The addition of external mirrors, particularly at the pumped surface, significantly reduces the threshold gain.Comment: 15 pages, 8 figure

    Humanised childbirth:the status of emotional support of women in rural Bangladesh

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    The World Health Organization has recently set standards emphasising the importance of emotional support during birth for improving the quality of maternal and newborn healthcare in facilities. In this study, we explore the emotional support status of women during birth in rural Bangladesh. A cross-sectional household survey of 1367 women was administered in 2018 in Brahmanbaria district. Outcomes of interest included: presence of a companion of choice; mobility; intake of fluids and food; and position of choice. Associations between outcomes of interest and background characteristics were explored through binary and multiple logistic regressions. Approximately 68% women had a companion of choice during labour or childbirth, significantly higher among women giving birth at home (75%) than in a health facility. Nearly 60% women were allowed to eat and drink during labour, also significantly higher among women giving birth at home. Seventy-per cent women were allowed to be ambulatory during labour (46% in a facility vs. 85% at home). Only 27% women were offered or allowed to give birth in the position of their choice at facility, compared to 54% giving birth at home. Among women giving birth in a facility who did not have a companion of choice, 39% reported that the health provider/health facility management did not allow this. Ensuring emotional support and thereby improving the quality of the experience of care within health facilities should be prioritised by the Bangladesh government both to improve health outcomes of women and newborns and also to promote more humanised, positive childbirth experiences.</p

    Pre-notched and corroded low cycle fatigue behaviour of a nickel based alloy for disc rotor applications

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    Currently there is doubt surrounding the suitability of chemically-induced stress independent pre-conditioning of specimens to simulate turbine corrosion prior to fatigue testing. the thick oxide scales developed using such techniques can lead to net section loss and typically a lack of grain boundary sulphide attack seen in components that experience stress. An alternative approach to a corrosion-fatigue test scenario is suggested by micro-notching fatigue specimens prior to low salt flux corrosion to form grain boundary sulphide particles within channel-like features akin to stress assisted morphologies. On fatigue testing, a trend was identified where a change of mechanism was observed. The grain boundary oxide likely formed in the wake of freshly precipitated sulphide particles fractures around segments of grains leading to a metal loss that contributes to a significant reduction in fatigue properties

    Designing Engaging Learning Experiences in Programming

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    In this paper we describe work to investigate the creation of engaging programming learning experiences. Background research informed the design of four fieldwork studies to explore how programming tasks could be framed to motivate learners. Our empirical findings from these four field studies are summarized here, with a particular focus upon one – Whack a Mole – which compared the use of a physical interface with the use of a screen-based equivalent interface to obtain insights into what made for an engaging learning experience. Emotions reported by two sets of participant undergraduate students were analyzed, identifying the links between the emotions experienced during programming and their origin. Evidence was collected of the very positive emotions experienced by learners programming with a physical interface (Arduino) in comparison with a similar program developed using a screen-based equivalent interface. A follow-up study provided further evidence of the motivation of personalized design of programming tangible physical artefacts. Collating all the evidence led to the design of a set of ‘Learning Dimensions’ which may provide educators with insights to support key design decisions for the creation of engaging programming learning experiences
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