1,270 research outputs found

    Interleaved Flyback Converter with Embedded Grid Interacting PV Cascaded MLI

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    The importance of extracting power from renewable energy sources are increasing in the modern world as the power demand is increasing day by day and the non renewable energy sources are getting dried up. Solar power is a domestic source of energy and its availability throughout the year makes it a primary target to solve this crisis. It will never produce any hazardous waste or pollution. But various issues like Power quality problems and Harmonic distortion seep in due to the intermittent nature of PV system. This paper proposes a cascaded H–bridge multilevel inverter for grid connected PV system with a flyback converter. This helps to achieve maximum power point tracking and also provides isolation which will further help to increase system efficiency. The DC–DC flyback converters are cascaded to generate multilevel output voltage. Then this multilevel dc output is given to H bridge inverter to generate multilevel output. A new control algorithm is used in this paper which combines voltage–hold Perturb and observe method and modified PWM algorithm which helps to achieve the best MPPT. The proposed topology is implemented in PSIM. The Simulation and Hardware results reveal that the suggested technique is highly

    Biomechanical analysis of temporomandibular joint dynamics based on real-time magnetic resonance imaging

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    Aim: The traditional hinge axis theory of temporomandibular joint (TMJ) dynamics is increasingly being replaced by the theory of instantaneous centers of rotation (ICR). Typically, ICR determinations are based on theoretical calculations or three-dimensional approximations of finite element models. Materials and methods: With the advent of real-time magnetic resonance imaging (MRI), natural physiologic movements of the TMJ may be visualized with 15 frames per second. The present study employs real-time MRI to analyze the TMJ biomechanics of healthy volunteers during mandibular movements, with a special emphasis on horizontal condylar inclination (HCI) and ICR pathways. The Wilcoxon rank sum test was used to comparatively analyze ICR pathways of mandibular opening and closure. Results: Mean HCI was 34.8 degrees (± 11.3 degrees) and mean mandibular rotation was 26.6 degrees (± 7.2 degrees). Within a mandibular motion of 10 to 30 degrees, the resulting x- and y-translation during opening and closure of the mandible differed significantly (10 to 20 degrees, x: P = 0.02 and y: P 30 degrees showed no significant differences in x- and y-translation. Near occlusion movements differed only for y-translation (P < 0.01). Conclusion: Real-time MRI facilitates the direct recording of TMJ structures during physiologic mandibular movements. The present findings support the theory of ICR. Statistics confirmed that opening and closure of the mandible follow different ICR pathways, which might be due to muscular activity discrepancies during different movement directions. ICR pathways were similar within maximum interincisal distance (MID) and near occlusion (NO), which might be explained by limited extensibility of tissue fibers (MID) and tooth contact (NO), respectively

    Differential cross-section measurements for the electroweak production of dijets in association with a Z boson in proton–proton collisions at ATLAS

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    Differential cross-section measurements are presented for the electroweak production of two jets in association with a Z boson. These measurements are sensitive to the vector-boson fusion production mechanism and provide a fundamental test of the gauge structure of the Standard Model. The analysis is performed using proton–proton collision data collected by ATLAS at s=13TeVs=13 TeV\sqrt{s}=13\ \hbox {TeV} and with an integrated luminosity of 139fb-1139 fb1139\ \hbox {fb}^{-1}. The differential cross-sections are measured in the Z→ℓ+ℓ-Z+Z\rightarrow \ell ^+\ell ^- decay channel (ℓ=e,μ=e,μ\ell =e,\mu ) as a function of four observables: the dijet invariant mass, the rapidity interval spanned by the two jets, the signed azimuthal angle between the two jets, and the transverse momentum of the dilepton pair. The data are corrected for the effects of detector inefficiency and resolution and are sufficiently precise to distinguish between different state-of-the-art theoretical predictions calculated using Powheg+Pythia8, Herwig7+Vbfnlo and Sherpa 2.2. The differential cross-sections are used to search for anomalous weak-boson self-interactions using a dimension-six effective field theory. The measurement of the signed azimuthal angle between the two jets is found to be particularly sensitive to the interference between the Standard Model and dimension-six scattering amplitudes and provides a direct test of charge-conjugation and parity invariance in the weak-boson self-interactions

    Measurements of the production cross-section for a Z boson in association with b-jets in proton-proton collisions at √s = 13 TeV with the ATLAS detector

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    This paper presents a measurement of the production cross-section of a Z boson in association with b-jets, in proton-proton collisions at √s = 13$ TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of 35.6 fb-1. Inclusive and differential cross-sections are measured for events containing a Z boson decaying into electrons or muons and produced in association with at least one or at least two b-jets with transverse momentum PT &gt; 20 GeV and rapidity |y| &lt;2.5. Predictions from several Monte Carlo generators based on leading-order (LO) or next-to-leading-order (NLO) matrix elements interfaced with a parton-shower simulation and testing different flavour schemes for the choice of initial-state partons are compared with measured cross-sections. The 5-flavour number scheme predictions at NLO accuracy agree better with data than 4-flavour number scheme ones. The 4-flavour number scheme predictions underestimate data in events with at least one b-jet

    Higgs boson production cross-section measurements and their EFT interpretation in the 4 ℓ decay channel at s = 13 TeV with the ATLAS detector

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    Abstract: Higgs boson properties are studied in the four-lepton decay channel (where lepton = e, μ) using 139 fb-1 of proton–proton collision data recorded at s=13 TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive cross-section times branching ratio for H→ZZ∗ decay is measured to be 1.34±0.12 pb for a Higgs boson with absolute rapidity below 2.5, in good agreement with the Standard Model prediction of 1.33±0.08 pb. Cross-sections times branching ratio are measured for the main Higgs boson production modes in several exclusive phase-space regions. The measurements are interpreted in terms of coupling modifiers and of the tensor structure of Higgs boson interactions using an effective field theory approach. Exclusion limits are set on the CP-even and CP-odd ‘beyond the Standard Model’ couplings of the Higgs boson to vector bosons, gluons and top quarks

    Search for heavy resonances decaying into a pair of Z bosons in the ℓ + ℓ - ℓ ′ + ℓ ′ - and ℓ + ℓ - ν ν ¯ final states using 139 fb - 1 of proton–proton collisions at s = 13 TeV with the ATLAS detector

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    Abstract: A search for heavy resonances decaying into a pair of Z bosons leading to ℓ+ℓ-ℓ′+ℓ′- and ℓ+ℓ-νν¯ final states, where ℓ stands for either an electron or a muon, is presented. The search uses proton–proton collision data at a centre-of-mass energy of 13 TeV collected from 2015 to 2018 that corresponds to the integrated luminosity of 139 fb-1 recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. Different mass ranges spanning 200 GeV to 2000 GeV for the hypothetical resonances are considered, depending on the final state and model. In the absence of a significant observed excess, the results are interpreted as upper limits on the production cross section of a spin-0 or spin-2 resonance. The upper limits for the spin-0 resonance are translated to exclusion contours in the context of Type-I and Type-II two-Higgs-doublet models, and the limits for the spin-2 resonance are used to constrain the Randall–Sundrum model with an extra dimension giving rise to spin-2 graviton excitations

    Measurement of the charge asymmetry in top-quark pair production in association with a photon with the ATLAS experiment

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    A measurement of the charge asymmetry in top-quark pair (tt ̄) production in association with a photon is presented. The measurement is performed in the single-lepton tt ̄ decay channel using proton–proton collision data collected with the ATLAS detector at the Large Hadron Collider at CERN at a centre-of-mass-energy of 13 TeV during the years 2015–2018, corresponding to an integrated luminosity of 139 fb−1. The charge asymmetry is obtained from the distribution of the difference of the absolute rapidities of the top quark and antiquark using a profile likelihood unfolding approach. It is measured to be AC=−0.003±0.029 in agreement with the Standard Model expectation

    Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

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    In the version of this article initially published, the ATLAS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the article

    Search for associated production of a Z boson with an invisibly decaying Higgs boson or dark matter candidates at s=13 TeV with the ATLAS detector

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    A search for invisible decays of the Higgs boson as well as searches for dark matter candidates, produced together with a leptonically decaying Z boson, are presented. The analysis is performed using proton−proton collisions at a centre-of-mass energy of 13 TeV, delivered by the LHC, corresponding to an integrated luminosity of 139 fb−1 and recorded by the ATLAS experiment. Assuming Standard Model cross-sections for ZH production, the observed (expected) upper limit on the branching ratio of the Higgs boson to invisible particles is found to be 19% (19%) at the 95% confidence level. Exclusion limits are also set for simplified dark matter models and two-Higgs-doublet models with an additional pseudoscalar mediator

    Search for events with a pair of displaced vertices from long-lived neutral particles decaying into hadronic jets in the ATLAS muon spectrometer in pp collisions at root s=13  TeV

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    A search for events with two displaced vertices from long-lived particle (LLP) pairs using data collected by the ATLAS detector at the LHC is presented. This analysis uses 139 fb-1 of proton-proton collision data at s=13 TeV recorded in 2015-2018. The search employs techniques for reconstructing vertices of LLPs decaying to jets in the muon spectrometer displaced between 3 and 14 m with respect to the primary interaction vertex. The observed numbers of events are consistent with the expected background and limits for several benchmark signals are determined. For the Higgs boson with a mass of 125 GeV, the paper reports the first exclusion limits for branching fractions into neutral long-lived particles below 0.1%, while branching fractions above 10% are excluded at 95% confidence level for LLP proper lifetimes ranging from 4 cm to 72.4 m. In addition, the paper present the first results for the decay of LLPs into tt¯ in the ATLAS muon spectrometer
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