Search results for "Width ratio"

showing 10 items of 12 documents

Experimental observations of upstream overdeepening

2005

The issue of morphodynamic influence in meandering streams is investigated through a series of laboratory experiments on curved and straight flumes. Both qualitative and quantitative observations confirm the suitability of the recent theoretical developments (Zolezzi & Seminara 2001) that indicate the occurrence of two distinct regimes of morphodynamic influence, depending on the value of the width ratio of the channel β. The threshold value βR separating the upstream from the downstream influence regimes coincides with the resonant value discovered by Blondeaux & Seminara (1985). Indeed it is observed that upstream influence may occur only in relatively wide channels, while narrower stream…

BedformMechanics of MaterialsMechanical EngineeringOverdeepeningThe issue of morphodynamic influence in meandering streams is investigated through a series of laboratory experiments on curved and straight flumes. Both qualitative and quantitative observations confirm the suitability of the recent theoretical developments (Zolezzi & Seminara 2001) that indicate the occurrence of two distinct regimes of morphodynamic influence depending on the value of the width ratio of the channel β. The threshold value βR separating the upstream from the downstream influence regimes coincides with the resonant value discovered by Blondeaux & Seminara (1985). Indeed it is observed that upstream influence may occur only in relatively wide channels while narrower streams are dominated by downstream influence. A series of experiments has been carried out in order to check the above theoretical predictions and show for the first time evidence of the occurrence of upstream overdeepening. Two different sets of experiments have been designed where a discontinuity in channel geometry was present such that the channel morphodynamics was influenced in the upstream direction under super-resonant conditions (β >βR) and in the downstream direction under sub-resonant conditions (β <βR). Experimental results give qualitative and quantitative support to the theoretical predictions and allow us to clarify the limits of the linear analysis.MechanicsLinear analysisCondensed Matter PhysicsWidth ratioGeology
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Fatigue Crack Growth Rate under Different Bending to Torsion Ratios in 10HNAP Steel

2011

The paper contains the fatigue test results of rectangular cross-section specimens made of 10HNAP steel. The specimen height to width ratio was 1.5. Bending with torsion tests were carried out for the following ratios of bending to torsional moments MaB / MaT = 0.47, 0.94, 1.87 and the loading frequency 26.5 Hz. The tests were performed in a high cycle fatigue regime for the stress ratio R = - 1 and phase shift between bending and torsion loading equal to  = 0.

Materials scienceMechanics of Materialsbusiness.industryStress ratioMechanical EngineeringTorsion (mechanics)General Materials ScienceStructural engineeringComposite materialParis' lawbusinessWidth ratioKey Engineering Materials
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A search for $\eta'_c$ production in photon-photon fusion at LEP

1998

A search for the production of the $\eta'_c$ meson, the first radial excitation of the ground state of charmonium $\eta_c$(2980), in the photon-photon fusion reaction at LEP has been performed using the data collected by the DELPHI detector during 1992-1996. No evidence of $\eta'_c$ production is found in the mass region 3520--3800 MeV/c^2. An upper limit for the ratio of the two-photon widths of the $\eta'_c$ and $\eta_c$ is obtained.

Nuclear and High Energy PhysicsParticle physicsPhotonMesonHigh Energy Physics::LatticeWidth ratio01 natural sciencesPartícules (Física nuclear)High Energy Physics - ExperimentNuclear physics0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Nuclear fusion010306 general physicsNuclear ExperimentDELPHIPhysicsFusion010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyLARGE ELECTRON POSITRON COLLIDERLarge Electron–Positron ColliderPARTICLE PHYSICS; LARGE ELECTRON POSITRON COLLIDER; DELPHIPARTICLE PHYSICSFísica nuclearHigh Energy Physics::ExperimentGround stateExcitationParticle Physics - Experiment
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Test of lepton flavour universality in K+→ℓ+ν decays

2011

Abstract A precision test of lepton flavour universality has been performed by measuring the ratio R K of kaon leptonic decay rates K + → e + ν and K + → μ + ν in a sample of 59 813 reconstructed K + → e + ν candidates with ( 8.71 ± 0.24 ) % background contamination. The result R K = ( 2.487 ± 0.013 ) × 10 − 5 is in agreement with the Standard Model expectation.

Nuclear physicsPhysicsNuclear and High Energy PhysicsParticle physicsFlavourWidth ratioUniversality (dynamical systems)LeptonPhysics Letters B
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Physiological advantages of dwarfing in surviving extinctions in high-CO2 oceans

2015

Excessive CO2 in the present-day ocean-atmosphere system is causing ocean acidification, and is likely to cause a severe biodiversity decline in the future, mirroring effects in many past mass extinctions. Fossil records demonstrate that organisms surviving such events were often smaller than those before, a phenomenon called the Lilliput effect. Here, we show that two gastropod species adapted to acidified seawater at shallow-water CO2 seeps were smaller than those found in normal pH conditions and had higher mass-specific energy consumption but significantly lower whole-animal metabolic energy demand. These physiological changes allowed the animals to maintain calcification and to partial…

Ocean Acidification International Coordination Centre (OA-ICC)IdentificationSalinityTemperateBicarbonate ion standard deviationBottles or small containers/Aquaria (<20 L)Alkalinity total standard deviationinorganicAlkalinityExperimentTemperature waterCarbon inorganic dissolvedWidthCalculated using seacarb after Nisumaa et al 2010Aragonite saturation stateRespiration rate oxygenAlkalinity totalBottles or small containers Aquaria 20 LtotalCO2 ventpHRespirationCalcification rate of calcium carbonateTemperatureMonthdissolvedCarbonate ionLaboratory experimentPartial pressure of carbon dioxide (water) at sea surface temperature (wet air)Temperature water standard deviationRespiration rateEarth System ResearchField observationstandard deviationThicknessCalcification/DissolutionPotentiometric titrationCalcite saturation statePotentiometricwaterPartial pressure of carbon dioxideSiteGrowth MorphologyFigureAragonite saturation state standard deviationBenthosMediterranean SeaOcean Acidification International Coordination Centre OA ICCCalcite saturation state standard deviationAnimaliaBicarbonate ionLONGITUDECalculated using seacarb after Nisumaa et al. (2010)SpeciesCyclope neriteaBottles or small containers/Aquaria (&lt;20 L)Calculated using CO2SYSHeightPartial pressure of carbon dioxide standard deviationCarbonate system computation flagpH standard deviationCarbonate ion standard deviationFugacity of carbon dioxide (water) at sea surface temperature (wet air)CarbonHeight/width ratioTreatmentPartial pressure of carbon dioxide water at sea surface temperature wet airCarbon dioxideMolluscaGrowth/MorphologySingle speciesCalcification DissolutionLATITUDEHeight width ratioBenthic animalsFugacity of carbon dioxide water at sea surface temperature wet airCoast and continental shelfNassarius corniculusoxygenTable
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Search forB±→[K∓π±]DK±and Upper Limit on theb→uAmplitude inB±→DK±

2004

We search for B±→[K∓π±]DK± decays, where [K∓π±]D indicates that the K∓π± pair originates from the decay of a D0 or D 0. Results are based on 120×106 Υ(4S)→BB decays collected with the BABAR detector at SLAC. We set an upper limit on the ratio RKπ≡ [Γ(B+→[K-π+]DK+)+Γ(B-→[K+π-]DK-)]/[Γ(B+→[K+π-]DK+)+Γ(B-→[K-π+]DK-)]<0.026 (90%   C.L.). This constrains the amplitude ratio rB≡ |A(B-→D 0K-)/A(B-→D0K-)|<0.22 (90% C.L.), consistent with expectations. The small value of rB favored by our analysis suggests that the determination of the Cabibbo-Kobayashi-Maskawa phase γ from B→DK will be difficult.

Physics010308 nuclear & particles physicsElectron–positron annihilationAnalytical chemistryGeneral Physics and AstronomyValue (computer science)Width ratio01 natural sciencesAmplitude ratioParticle decayAmplitudeClassical mechanics0103 physical sciencesLimit (mathematics)010306 general physicsPhysical Review Letters
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Measurements ofCP-Violating Asymmetries and Branching Fractions inBMeson Decays toη′K

2006

We present measurements of CP-violating asymmetries and branching fractions for the decays B+->omega pi(+), B+->omega K+, and B-0 ->omega K-0. The data sample corresponds to 232x10(6) B (B) over bar pairs produced by e(+)e(-) annihilation at the Upsilon(4S) resonance. For the decay B-0 ->omega K-S(0), we measure the time-dependent CP-violation parameters S=0.51(-0.39)(+0.35)+/- 0.02, and C=-0.55(-0.26)(+0.28)+/- 0.03. We also measure the branching fractions, in units of 10(-6), B(B+->omega pi(+))=6.1 +/- 0.7 +/- 0.4, B(B+->omega K+)=6.1 +/- 0.6 +/- 0.4, and B(B-0 ->omega K-0)=6.2 +/- 1.0 +/- 0.4, and charge asymmetries A(ch)(B+->omega pi(+))=-0.01 +/- 0.10 +/- 0.01 and A(ch)(B+->omega K+)=0…

PhysicsNuclear and High Energy PhysicsAnnihilation010308 nuclear & particles physicsElectron–positron annihilationAnalytical chemistryResonanceGeneral Physics and AstronomyBranching (polymer chemistry)Width ratioOmega01 natural sciencesNuclear physicsNuclear magnetic resonance0103 physical sciencesPiCP violationB meson010306 general physicsPhysical Review Letters
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Study of the leptonic decays of the Z0 boson

1990

Measurements are presented of the cross section ratios Rℓ = σℓ(e+e-→ℓ+ℓ -)/σhh(e+e-→hadrons) for ℓ = e, μ and τ using data taken from a scan around the Z0. The results are Re = (5.09±0.32±0.18)%, Rμ = (4.96±0.35±0.17)% and Rτ,=(4.72±0.38± 0.29)% where, for the ratio Re, the t-channel contribution has been subtracted. These results are consistent with the hypothesis of lepton universality and test this hypothesis at the energy scale s ∼ 8300 GeV2. The absolute cross sections σℓ(e+e-→ℓ +ℓ-) have also been measured. From the cross sections the leptonic partial widths Γe = (83.2±3.0±2.4) MeV, (ΓeΓμ) 1/2=(84.6±3.0±2.4) MeV and (ΓeΓτ) 1/2=(82.6±3.3±3.2) MeV have been extracted. Assuming lepton un…

PhysicsNuclear and High Energy PhysicsParticle physics[PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex]010308 nuclear & particles physicsElectron–positron annihilationHadronWidth ratio01 natural sciences7. Clean energyNuclear physics0103 physical sciencesPhysique des particules élémentaires[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Neutrino010306 general physicsParticle Physics - ExperimentLeptonBosonPhysics Letters B
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Two-photon widths of theχc0,2states and helicity analysis forχc2→γγ

2012

Based on a data sample of 106 X 10(6) psi' events collected with the BESIII detector, the decays psi' -> gamma chi(c0,2), chi(c0,2) -> gamma gamma are studied to determine the two-photon widths of the chi(c0,2) states. The two-photon decay branching fractions are determined to be B(chi(c0) -> gamma gamma) = (2.24 +/- 0.19 +/- 0.12 +/- 0.08) X 10(-4) and B(chi(c2) -> gamma gamma) = (3.21 +/- 0.18 +/- 0.17 +/- 0.13) X 10(-4) From these, the two-photon widths are determined to be Gamma(gamma gamma)(chi(c0)) = (2.33 +/- 0.20 +/- 0.13 +/- 0.17) keV, Gamma(gamma gamma)(chi(c2)) = (0.63 +/- 0.04 +/- 0.04 +/- 0.04) keV, and R = Gamma(gamma gamma)(chi(c2))/Gamma(gamma gamma)(chi(c0)) = 0.271 +/- 0.0…

PhysicsNuclear physicsNuclear and High Energy PhysicsAnnihilationElectron–positron annihilationLambdaWidth ratioHelicityEvent generatorGamma gammaPhysical Review D
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The Ratio R of hadronic and electronic Z widths and the strong coupling constant alpha-s

1994

Abstract We review the relation between the ratio of hadronic and electronic Z widths, R = Γ( Z → q q )/Γ( Z → e + e − ) and the strong coupling constant at the Z mass, αs. The theoretical uncertainty of αs derived from R is estimated to be Δα s = ±0.002 (electroweak) ± 0.002 (QCD) −0.003 +0.004 (m top , m Higgs ) .

Quantum chromodynamicsCoupling constantPhysicsNuclear and High Energy PhysicsParticle physicsHigh Energy Physics::PhenomenologyHadronElectroweak interactionWidth ratiolcsh:QC1-999Nuclear physicsHiggs bosonStrong couplingHigh Energy Physics::ExperimentAstrophysics::Earth and Planetary Astrophysicslcsh:PhysicsParticle Physics - Phenomenology
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