819 research outputs found

    A Physical Internet-enabled Building Information Modelling System For Prefabricated Construction

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    Prefabricated construction is believed to be energy conserving though opportunities for achieving higher energy efficiency have yet to be fully harnessed. From investigation of a prefabricated construction project in Hong Kong, two main problems have been revealed relating to energy consumption, including: i) inefficient management of resources such as labours and machines, and ii) inefficient production, transportation, and on-site assembly of prefabricated components. These problems are primarily caused by lagged information communication and human errors. This paper seeks to offer a solution by developing a Physical Internet-enabled Building Information Modelling System (PI-BIMS) that integrates Auto-ID technologies, BIM, and cloud computing. The PI-BIMS enables real-time collection, communication, and visualization of information across the processes of production, transportation, and on-site assembly. Practical issues of the system implementation are provided through a pilot prototype. It is found that the PI-BIMS helps enhance the resource allocation efficiency and decrease human errors. Thus, an alternative opportunity to improve energy efficiency in prefabricated construction has become possible

    Influence of large-scale interplanetary structures on the propagation of solar energetic particles: The Multispacecraft event on 2021 October 9

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    An intense solar energetic particle (SEP) event was observed on 2021 October 9 by multiple spacecraft distributed near the ecliptic plane at heliocentric radial distances R ≲ 1 au and within a narrow range of heliolongitudes. A stream interaction region (SIR), sequentially observed by Parker Solar Probe (PSP) at R = 0.76 au and 48° east from Earth (ϕ = E48°), STEREO-A (at R = 0.96 au, ϕ = E39°), Solar Orbiter (SolO; at R = 0.68 au, ϕ = E15°), BepiColombo (at R = 0.33 au, ϕ = W02°), and near-Earth spacecraft, regulated the observed intensity-time profiles and the anisotropic character of the SEP event. PSP, STEREO-A, and SolO detected strong anisotropies at the onset of the SEP event, which resulted from the fact that PSP and STEREO-A were in the declining-speed region of the solar wind stream responsible for the SIR and from the passage of a steady magnetic field structure by SolO during the onset of the event. By contrast, the intensity-time profiles observed near Earth displayed a delayed onset at proton energies ≳13 MeV and an accumulation of ≲5 MeV protons between the SIR and the shock driven by the parent coronal mass ejection (CME). Even though BepiColombo, STEREO-A, and SolO were nominally connected to the same region of the Sun, the intensity-time profiles at BepiColombo resemble those observed near Earth, with the bulk of low-energy ions also confined between the SIR and the CME-driven shock. This event exemplifies the impact that intervening large-scale interplanetary structures, such as corotating SIRs, have in shaping the properties of SEP events

    Measurements of the observed cross sections for e+e−→e^+e^-\to exclusive light hadrons containing π0π0\pi^0\pi^0 at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV

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    By analyzing the data sets of 17.3, 6.5 and 1.0 pb−1^{-1} taken, respectively, at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for e+e−→π+π−π0π0e^+e^-\to \pi^+\pi^-\pi^0\pi^0, K+K−π0π0K^+K^-\pi^0\pi^0, 2(π+π−π0)2(\pi^+\pi^-\pi^0), K+K−π+π−π0π0K^+K^-\pi^+\pi^-\pi^0\pi^0 and 3(π+π−)π0π03(\pi^+\pi^-)\pi^0\pi^0 at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay into these final states at 90% C.L..Comment: 7 pages, 2 figure

    Partial wave analysis of J/\psi \to \gamma \phi \phi

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    Using 5.8×107J/ψ5.8 \times 10^7 J/\psi events collected in the BESII detector, the radiative decay J/ψ→γϕϕ→γK+K−KS0KL0J/\psi \to \gamma \phi \phi \to \gamma K^+ K^- K^0_S K^0_L is studied. The ϕϕ\phi\phi invariant mass distribution exhibits a near-threshold enhancement that peaks around 2.24 GeV/c2c^{2}. A partial wave analysis shows that the structure is dominated by a 0−+0^{-+} state (η(2225)\eta(2225)) with a mass of 2.24−0.02+0.03−0.02+0.032.24^{+0.03}_{-0.02}{}^{+0.03}_{-0.02} GeV/c2c^{2} and a width of 0.19±0.03−0.04+0.060.19 \pm 0.03^{+0.06}_{-0.04} GeV/c2c^{2}. The product branching fraction is: Br(J/ψ→γη(2225))⋅Br(η(2225)→ϕϕ)=(4.4±0.4±0.8)×10−4Br(J/\psi \to \gamma \eta(2225))\cdot Br(\eta(2225)\to \phi\phi) = (4.4 \pm 0.4 \pm 0.8)\times 10^{-4}.Comment: 11 pages, 4 figures. corrected proof for journa

    Measurements of the observed cross sections for exclusive light hadron production in e^+e^- annihilation at \sqrt{s}= 3.773 and 3.650 GeV

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    By analyzing the data sets of 17.3 pb−1^{-1} taken at s=3.773\sqrt{s}=3.773 GeV and 6.5 pb−1^{-1} taken at s=3.650\sqrt{s}=3.650 GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 12 exclusive light hadron final states produced in e+e−e^+e^- annihilation at the two energy points. We have also set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay to these final states at 90% C.L.Comment: 8 pages, 5 figur

    Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays

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    By analyzing about 33 pb−1\rm pb^{-1} data sample collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we directly measure the branching fractions for the neutral and charged DD inclusive semimuonic decays to be BF(D0→μ+X)=(6.8±1.5±0.7)BF(D^0 \to \mu^+ X) =(6.8\pm 1.5\pm 0.7)% and BF(D+→μ+X)=(17.6±2.7±1.8)BF(D^+ \to \mu^+ X) =(17.6 \pm 2.7 \pm 1.8)%, and determine the ratio of the two branching fractions to be BF(D+→μ+X)BF(D0→μ+X)=2.59±0.70±0.25\frac{BF(D^+ \to \mu^+ X)}{BF(D^0 \to \mu^+ X)}=2.59\pm 0.70 \pm 0.25

    Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-

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    We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi --> D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7 J/Psi events collected with the BESII detector at the BEPC. No excess of signal above background is observed, and 90% confidence level upper limits on the branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi --> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure

    A study of charged kappa in J/ψ→K±Ksπ∓π0J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0

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    Based on 58×10658 \times 10^6 J/ψJ/\psi events collected by BESII, the decay J/ψ→K±Ksπ∓π0J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0 is studied. In the invariant mass spectrum recoiling against the charged K∗(892)±K^*(892)^{\pm}, the charged κ\kappa particle is found as a low mass enhancement. If a Breit-Wigner function of constant width is used to parameterize the kappa, its pole locates at (849±77−14+18)−i(256±40−22+46)(849 \pm 77 ^{+18}_{-14}) -i (256 \pm 40 ^{+46}_{-22}) MeV/c2c^2. Also in this channel, the decay J/ψ→K∗(892)+K∗(892)−J/\psi \to K^*(892)^+ K^*(892)^- is observed for the first time. Its branching ratio is (1.00±0.19−0.32+0.11)×10−3(1.00 \pm 0.19 ^{+0.11}_{-0.32}) \times 10^{-3}.Comment: 14 pages, 4 figure

    Measurements of psi(2S) decays to octet baryon-antibaryon pairs

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    With a sample of 14 million psi(2S) events collected by the BESII detector at the Beijing Electron Positron Collider (BEPC), the decay channels psi(2S)->p p-bar, Lambda Lambda-bar, Sigma0 Sigma0-bar, Xi Xi-bar are measured, and their branching ratios are determined to be (3.36+-0.09+-0.24)*10E-4, (3.39+-0.20+-0.32)*10E-4, (2.35+-0.36+-0.32)*10E-4, (3.03+-0.40+-0.32)*10E-4, respectively. In the decay psi(2S)->p p-bar, the angular distribution parameter alpha is determined to be 0.82+-0.17+-0.04.Comment: 8 pages, 8 figure

    Direct Measurements of the Branching Fractions for D0→K−e+νeD^0 \to K^-e^+\nu_e and D0→π−e+νeD^0 \to \pi^-e^+\nu_e and Determinations of the Form Factors f+K(0)f_{+}^{K}(0) and f+π(0)f^{\pi}_{+}(0)

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    The absolute branching fractions for the decays D0→K−e+νeD^0 \to K^-e ^+\nu_e and D0→π−e+νeD^0 \to \pi^-e^+\nu_e are determined using 7584±198±3417584\pm 198 \pm 341 singly tagged Dˉ0\bar D^0 sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC. In the system recoiling against the singly tagged Dˉ0\bar D^0 meson, 104.0±10.9104.0\pm 10.9 events for D0→K−e+νeD^0 \to K^-e ^+\nu_e and 9.0±3.69.0 \pm 3.6 events for D0→π−e+νeD^0 \to \pi^-e^+\nu_e decays are observed. Those yield the absolute branching fractions to be BF(D0→K−e+νe)=(3.82±0.40±0.27)BF(D^0 \to K^-e^+\nu_e)=(3.82 \pm 0.40\pm 0.27)% and BF(D0→π−e+νe)=(0.33±0.13±0.03)BF(D^0 \to \pi^-e^+\nu_e)=(0.33 \pm 0.13\pm 0.03)%. The vector form factors are determined to be ∣f+K(0)∣=0.78±0.04±0.03|f^K_+(0)| = 0.78 \pm 0.04 \pm 0.03 and ∣f+π(0)∣=0.73±0.14±0.06|f^{\pi}_+(0)| = 0.73 \pm 0.14 \pm 0.06. The ratio of the two form factors is measured to be ∣f+π(0)/f+K(0)∣=0.93±0.19±0.07|f^{\pi}_+(0)/f^K_+(0)|= 0.93 \pm 0.19 \pm 0.07.Comment: 6 pages, 5 figure
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