The NOvA experiment has seen a 4.4σ signal of ν¯e appearance in a 2 GeV ν¯μ beam at a distance of 810 km. Using 12.33×1020 protons on target delivered to the Fermilab NuMI neutrino beamline, the ...experiment recorded 27 ν¯μ→ν¯e candidates with a background of 10.3 and 102 ν¯μ→ν¯μ candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Δm322|=2.48−0.06+0.11×10−3 eV2/c4 and sin2θ23 in the ranges from (0.53–0.60) and (0.45–0.48) in the normal neutrino mass hierarchy. The data exclude most values near δCP=π/2 for the inverted mass hierarchy by more than 3σ and favor the normal neutrino mass hierarchy by 1.9σ and θ23 values in the upper octant by 1.6σ.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
Using a beam made (mainly) by muon neutrinos traveling through the earth, the NOvA Experiment looks for the appearance of electron neutrinos, a transformation explained by the quantum-mechanical ...phenomenon known as neutrino oscillation. NOvA uses two neutrino detectors located 14.6 mrad off-axis from the main beam direction. The first (Near) detector stands at a distance of 1 km from the neutrino source, while the second (Far) one is at 810 km. Traveling from the Near Detector to the Far Detector, muon neutrinos can morph into electron neutrinos with a probability depending upon the parameters Δm322 and sin2 θ23, among others. By comparing the observed number of νµ and νe events at the Far Detector with the expected number of events predicted by a 3-neutrino oscillation model, NOvA is able to measure these parameters and help to improve our understanding about neutrinos. After a brief introduction to the physics of neutrinos and a presentation of the experiment, in this talk the most recent results obtained by NOvA through the study of muon neutrino oscillations νµ → νµ and νµ → νe, are shown. The oscillation parameters are found to be Δm322=2.44×10−3eV2 and sin2 θ23 = 0.56.
A study on the effects of implementing the Granda–Oliveros infrared cutoff in the recently introduced Barrow holographic dark energy model is presented, and its cosmological evolution is ...investigated. We find how the deformation parameter,
Δ
, affects the evolution of
H
(
z
) and that from this model it is possible to obtain an accelerated expansion regime of the universe at late times. We also observe that increasing
Δ
causes a transition of the EoS parameter from quintessence to phantom regimes. In addition, we show that the model can be used to describe the know eras of dominance. Finally, after studying the stability of the proposed model, a fit of the corresponding parameters is preformed, utilizing the measurements of the expansion rate of the universe,
H
(
z
). The best fit of the parameters is found to be
(
α
,
β
,
Δ
)
=
1
.
00
-
0.02
+
0.02
,
0
.
69
-
0.02
+
0.03
,
0
.
000
-
0.000
+
0.004
at
1
σ
C.L., for which the Bekenstein–Hawking relation is favored.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A new technique is proposed in this paper to produce jets, droplets, and emulsions with sizes ranging from tens of microns down to the submicrometer scale. Liquid is injected at a constant flow rate ...through a hypodermic needle to form a film over the needle's outer surface. This film flows toward the needle tip until a liquid ligament is steadily ejected. Both the film motion and the liquid ejection are driven by the viscous and pressure forces exerted by a coflowing fluid stream. If this stream is a high-speed gas current, the outcome is a capillary jet which breaks up into droplets due to the Rayleigh instability. Micrometer emulsions are also produced by this instability mechanism when the injected liquid is focused by a viscous liquid stream. The minimum flow rates reached with the proposed technique are two orders of magnitude lower than those of the standard flow focusing configuration. This sharp reduction of the minimum flow rate allows one to form steady jets with radii down to the submicrometer scale. The stability of this new configuration is analyzed experimentally for both gas-liquid and liquid-liquid systems. In most of the cases, the loss of stability must be attributed to the liquid source because the critical Weber (capillary) number for the gas-liquid (liquid-liquid) case was significantly greater than the value corresponding to the convective/absolute instability transition in the jet.
We study both theoretically and experimentally the forced and free oscillations of a viscoelastic pendant drop in the linear regime. The Jeffreys model is numerically solved using the zero-shear ...viscosity of the steady shear flow in a rotational rheometer, and the stress relaxation time measured with a filament stretching elongational rheometer. The damping factor characterizing the first oscillation mode is one order of magnitude larger than that measured in the experiments. Three possible conclusions can be drawn from this study: (i) the Jeffreys model severely underestimates the viscosity decrease due to elasticity; (ii) the zero-shear viscosity measured in the rotational rheometer is much larger than the effective viscosity responsible for energy dissipation in the pendant droplet oscillations; and (iii) the relaxation time measured with the filament stretching elongational rheometer is much smaller than that characterizing those oscillations. The failure of the Jeffreys model necessarily entails that of all nonlinear constitutive relationships which the Jeffreys model can be derived from, like the commonly used Oldroyd-B model.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Uncertainty budget model for worm and worm gear single-flank rolling tests.•Identification of error sources affecting the gears’ dynamic measuring process.•Optimized uncertainty model minimizing the ...effects of main error contributions.•Free-eccentricity assembling of gears and minimum guides backlash are key factors.
This work presents the development of a new uncertainty budget model for worm and worm gear single-flank rolling tests. Also known as tangential composite test, this functional test offers an alternative way to analytical measurements to verify the accuracy grade of a gear obtaining also geometric information. The lack of available standards for the evaluation and calibration of these test equipment generates repeatable testers but not comparable ones because of the lack of traceability in the test results. The authors identified in this paper the different error sources affecting the dynamic measuring process, weighting them with the corresponding experimentally quantified sensitivity factors. The global expanded uncertainty of Fi′, fi′ and Fp′ parameters was calculated for an industrial single flank rolling tester. This uncertainty budget served as a basis for defining an optimized model that minimizes the effects of the main error contributions in worm and worm gear single-flank rolling tests.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The cross section of neutrino-induced neutral-current coherent π0 production on a carbon-dominated target is measured in the NOvA near detector. This measurement uses a narrow-band neutrino beam with ...an average neutrino energy of 2.7 GeV, which is of interest to ongoing and future long-baseline neutrino oscillation experiments. The measured, flux-averaged cross section is σ = 13.8 ± 0.9 ( stat ) ± 2.3 ( syst ) × 10−40 cm2 / nucleus , consistent with model prediction. This result is the most precise measurement of neutral-current coherent π 0 production in the few-GeV neutrino energy region.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
We propose a modified flow focusing configuration to produce low-viscosity microjets at much smaller flow rates than those reached by the standard configuration. In the modified flow focusing device, ...a sharpened rod blocks the recirculation cell appearing in the tapering liquid meniscus for low flow rates, which considerably improves its stability. We measured the minimum flow rates attainable with the modified configuration and compared the results with the corresponding values for the standard technique. For moderate and large applied pressure drops, the minimum flow rate reached with the modified configuration was about five times smaller than its counterpart in the standard configuration. The Weber numbers of the jets produced with the modified flow focusing configuration were considerably smaller than those with the standard technique. Numerical simulations were conducted to show how the presence of the inner rod substantially changes the flow pattern in the liquid meniscus.
Focusing liquid microjets with nozzles Acero, A J; Ferrera, C; Montanero, J M ...
Journal of micromechanics and microengineering,
06/2012, Volume:
22, Issue:
6
Journal Article
Peer reviewed
Open access
The stability of flow focusing taking place in a converging-diverging nozzle, as well as the size of the resulting microjets, is examined experimentally in this paper. The results obtained in most ...aspects of the problem are similar to those of the classical plate-orifice configuration. There is, however, a notable difference between flow focusing in nozzles and in the plate-orifice configuration. In the former case, the liquid meniscus oscillates laterally (global whipping) for a significant area of the control parameter plane, a phenomenon never observed when focusing with the plate-orifice configuration. Global whipping may constitute an important drawback of flow focusing with nozzles because it reduces the robustness of the technique.
PDF
