270 research outputs found

    Automated link analysis using radio frequency identification (RFID)

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    Being able to accurately record the interactions which take place within any environment is beneficial for understanding human behaviour in a wide range of industries. Link Analysis is a standard technique which is often used, but traditional pen and paper methods are cumbersome and time consuming. This paper details a way to automate recording the interactions between a human and their current environment by using radio frequency identification (RFID) tags and a subject-mounted receiver. Using the results from the system, it is possible to instantly create conventional Link Analysis diagrams and tables, reducing the time and resources required for data collection and analysis. The system has been developed in partnership with the Healthcare Ergonomics and Patient Safety Unit (HEPSU) at Loughborough University, with initial focus being on monitoring paramedics, patients and environment interactions within an ambulance; however, the technologies and the analyser system are not limited to use within this particular field

    Short-term performance variations of different photovoltaic system technologies under the humid subtropical climate of Kanpur in India

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    The study discusses the short-term performance variations of grid-connected photovoltaic (PV) systems installed in Kanpur, India. The analysis presents a holistic view of the performance variations of three PV array technologies [multi-crystalline (multi-Si), copper indium gallium diselenide and amorphous silicon] and two inverter types (high-frequency transformer and low-frequency transformer). The analysis considers the DC–AC conversion efficiency of the inverter, system performance through performance ratio (PR) calculations, energy variations between fixed and tracking systems and the comparison between calculated and simulated data for the examined period. The energy output difference between the tracking and fixed systems of the same PV technology show that these are dependent on differences in temperature coefficient, shading and other system related issues. The PR analysis shows the effect of temperature on the multi-Si system. The difference between the simulated and measured values of the systems was mostly attributed to the irradiance differences. Regarding the inverter evaluation, the results showed that both inverter types underperformed in terms of the conversion efficiency compared with nameplate values

    Organization theory and military metaphor: time for a reappraisal?

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    A ‘conventional’ use of military metaphor would use it to convey attributes such as hierarchical organization, vertical communication and limited autonomy. This is often used in contrast to a looser form of organization based on the metaphor of the network. However, this article argues that military practice is more complex, with examples of considerable autonomy within the constraints of central direction. It is suggested that not only might this be a more useful metaphor for many contemporary organizations, but also that simplistic uses of military metaphor divert our attention away from the functions that management hierarchies play. The discussion is embedded within a critical realist account of metaphor, arguing for both its value and the need for its further development

    Recoil Polarization Measurements of the Proton Electromagnetic Form Factor Ratio to Q^2 = 8.5 GeV^2

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    Among the most fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents; indeed, recent proton data have attracted intense theoretical interest. In this letter, we report new measurements of the proton electromagnetic form factor ratio using the recoil polarization method, at momentum transfers Q2=5.2, 6.7, and 8.5 GeV2. By extending the range of Q2 for which GEp is accurately determined by more than 50%, these measurements will provide significant constraints on models of nucleon structure in the non-perturbative regime

    Single Spin Asymmetries of Inclusive Hadrons Produced in Electron Scattering from a Transversely Polarized 3^3He Target

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    We report the first measurement of target single-spin asymmetries (AN_N) in the inclusive hadron production reaction, e e~+ 3He↑→h+X~^3\text{He}^{\uparrow}\rightarrow h+X, using a transversely polarized 3^3He target. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Three types of hadrons (π±\pi^{\pm}, K±\text{K}^{\pm} and proton) were detected in the transverse hadron momentum range 0.54 <pT<<p_T< 0.74 GeV/c. The range of xFx_F for pions was -0.29 <xF<<x_F< -0.23 and for kaons -0.25 <xF<<x_F<-0.18. The observed asymmetry strongly depends on the type of hadron. A positive asymmetry is observed for π+\pi^+ and K+\text{K}^+. A negative asymmetry is observed for π−\pi^{-}. The magnitudes of the asymmetries follow ∣Aπ−∣<∣Aπ+∣<∣AK+∣|A^{\pi^-}| < |A^{\pi^+}| < |A^{K^+}|. The K−^{-} and proton asymmetries are consistent with zero within the experimental uncertainties. The π+\pi^{+} and π−\pi^{-} asymmetries measured for the 3^3He target and extracted for neutrons are opposite in sign with a small increase observed as a function of pTp_T.Comment: Updated version, submitted to Phys. Rev.

    Single Spin Asymmetries in Charged Kaon Production from Semi-Inclusive Deep Inelastic Scattering on a Transversely Polarized 3He^3{\rm{He}} Target

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    We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He^3{\rm{He}} target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1<<xbjx_{bj}<<0.4 for K+K^{+} and K−K^{-} production. While the Collins and Sivers moments for K+K^{+} are consistent with zero within the experimental uncertainties, both moments for K−K^{-} favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the K+K^{+} Sivers moments are consistent with the prediction, the K−K^{-} results differ from the prediction at the 2-sigma level.Comment: 6 pages, 3 figure

    Double Spin Asymmetries of Inclusive Hadron Electroproductions from a Transversely Polarized 3He^3\rm{He} Target

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    We report the measurement of beam-target double-spin asymmetries (ALTA_\text{LT}) in the inclusive production of identified hadrons, e⃗ \vec{e}~+ 3He↑→h+X~^3\text{He}^{\uparrow}\rightarrow h+X, using a longitudinally polarized 5.9 GeV electron beam and a transversely polarized 3He^3\rm{He} target. Hadrons (π±\pi^{\pm}, K±K^{\pm} and proton) were detected at 16∘^{\circ} with an average momentum =2.35 GeV/c and a transverse momentum (pTp_{T}) coverage from 0.60 to 0.68 GeV/c. Asymmetries from the 3He^3\text{He} target were observed to be non-zero for π±\pi^{\pm} production when the target was polarized transversely in the horizontal plane. The π+\pi^{+} and π−\pi^{-} asymmetries have opposite signs, analogous to the behavior of ALTA_\text{LT} in semi-inclusive deep-inelastic scattering.Comment: Published in PRC (92.015207), nuclear experiment, high-energy experimen

    A precise extraction of the induced polarization in the 4He(e,e'p)3H reaction

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    We measured with unprecedented precision the induced polarization Py in 4He(e,e'p)3H at Q^2 = 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2. The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are over-estimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin independent charge-exchange term in the latter calculation.Comment: submitted to Physical Review Letter
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