Corrosion inhibition effect of
Justicia gendarussa extract (JGPE) on mild steel in 1
M HCl medium has been investigated by weight loss and electrochemical techniques. Inhibition efficiency of 93% was ...achieved with 150
ppm JGPE at 25
°C. The polarization studies showed that JGPE acts as mixed-type inhibitor. The Nyquist plots showed that on increasing JGPE concentration, increases charge transfer resistance and decreases double layer capacitance. JGPE obeys the Langmuir adsorption isotherm. AFM and ESCA confirmed the adsorption of JGPE on mild steel surface. Finally, JGPE inhibition efficiency was discussed in terms of adsorption and protective film formation.
Using the well established principles of Lorentz invariance, CP and CPT symmetry, and quantum statistics we do a model-independent study of effects of possible non-standard couplings of (Dirac and ...Majorana) neutrinos. The study is sensitive to the different quantum statistical properties of the Dirac and Majorana neutrinos which, contrary to neutrino-mediated processes of lepton number violation, could lead to observable effects
not
suppressed by the small ratios of neutrino and heavier particle masses. For processes with a neutrino-antineutrino pair of the same flavor in the final state, we formulate the “Dirac Majorana confusion theorem (DMCT)” showing why it is normally very difficult to observe the different behaviour of both kinds of neutrinos in experiments if they have only the standard model (SM)-like left-handed vector couplings to gauge bosons. We discuss deviations from the confusion theorem in the presence of non-standard neutrino interactions, allowing to discover or constrain such novel couplings. We illustrate the general results with two chosen examples of neutral current processes,
Z
→
ν
ν
¯
and
P
i
→
P
f
ν
ν
¯
(with
P
i
,
f
denoting pseudoscalar mesons, such as
B
,
K
,
π
). Our analysis shows that using 3-body decays the presence of non-standard interactions can not only be constrained but one can also distinguish between Dirac and Majorana neutrino possibilities.
A computational analysis of heat transfer augmentation and flow characteristics due to artificial roughness in the form of ribs on a broad, heated wall of a rectangular duct for turbulent flow ...(Reynolds number range 3000–20,000, which is relevant in solar air heater) has been carried out. Shear stress transport
k−
ω turbulence model is selected by comparing the predictions of different turbulence models with experimental results available in the literature. A detailed analysis of heat transfer variation within inter rib region is done by using the selected turbulence model. The analysis shows that peak in local heat transfer coefficient occurs at the point of reattachment of the separated flow as observed experimentally. The results predict a significant enhancement of heat transfer in comparison to that for a smooth surface. There is a good matching between the predictions by SST
k−
ω and experimental results. In this work, nine different shapes of rib are examined using SST
k−
ω model and compared on the basis of heat transfer enhancement, friction characteristics and performance index considering heat transfer enhancement with the same pumping power.
A
bstract
The disagreement between the standard model prediction and the experimental measurement of muon anomalous magnetic moment can be alleviated by invoking an additional particle which is ...either a vector boson (
X
1
) or a scalar (
X
0
). This new particle, with the mass
m
X
≲ 2
m
μ
, can be searched for in the decay
J
/
ψ → μ
−
μ
+
X
, where
X
is missing. Our numerical study shows that the search is quite feasible at the BESIII experiment in the parameter space allowed by muon
g −
2 measurements.
We present, how a systematic study of
B
→
D
ℓ
N
(
D
→
K
ℓ
N
) decays with
ℓ
=
μ
,
τ
, at Belle II (BESIII) can provide unambiguous signature of a heavy neutrino
N
and/or constrain its mixing with ...active neutrinos
ν
ℓ
, which is parameterized by
|
U
ℓ
N
|
2
. Our constraint on
|
U
μ
N
|
2
that can be achieved from the full Belle II data is comparable with what can be obtained from the much larger data set of the upgraded LHCb. Additionally, our method offers better constraint on
|
U
μ
N
|
2
for mass of sterile neutrino
m
N
<
2
GeV. We can also probe the Dirac and Majorana nature of
N
by observing the sequential decay of
N
, including suppression from observation of a displaced vertex as well as helicity flip, for Majorana
N
.
The scattering of flexural-gravity waves in a thin floating plate is investigated in the presence of compression. In this case, wave blocking occurs, which is associated with both a zero in the group ...velocity and coalition of two or more roots of the related dispersion relation. There exists a region in the frequency space in which there are three real roots of the dispersion equation and hence three propagating modes. This multiplicity leads to mode conversion when scattering occurs. In one of these modes, the energy propagation direction is opposite to the wavenumber, making enforcement of the Sommerfeld radiation condition challenging. The focus here is on a canonical problem in flexural-gravity wave scattering, the scattering of waves by a crack. Formulae are developed that apply uniformly at all frequencies, including through the blocking frequencies. This solution is developed by tracking the movement of the dispersion relation roots carefully in the complex plane. The mode conversion is verified by the scattering matrix of the process and through an energy identity. This energy identity for the case of more than one progressive modes is established using Green's theorem and later applied in the scattering matrix to identify the incident and transmitted waves in the scattering process and derive the radiation condition. Appropriate scaling of the reflection and transmission coefficients are provided with the energy identity. The solution method is illustrated with numerical examples.
Abstract
Isotope shifts (ISs) of atomic energy levels are sensitive probes of nuclear structure and new physics beyond the standard model. We present an analysis of the ISs of the cadmium atom (Cd I) ...and singly charged cadmium ion (Cd II). ISs of the 229 nm, 326 nm, 361 nm and 480 nm lines of Cd I are measured with a variety of techniques; buffer–gas-cooled beam spectroscopy, capturing atoms in a magneto-optic-trap, and optical pumping. IS constants for the D
1
and D
2
lines of Cd II are calculated with high accuracy by employing analytical response relativistic coupled-cluster theory in the singles, doubles and triples approximations. Combining the calculations for Cd II with experiments, we infer IS constants for all low-lying transitions in Cd I. We benchmark existing calculations via different many-body methods against these constants. Our calculations for Cd II enable nuclear charge radii of Cd isotopes to be extracted with unprecedented accuracy. The combination of our precise calculations and measurements shows that King plots for Cd I can improve the state-of-the-art sensitivity to a new heavy boson by up to two orders of magnitude.
Nickel (Ni)-doped Copper ferrite (inverse spinel ferrite)
Cu
1
-
X
Ni
X
Fe
2
O
4
(
x
= 0.00, 0.05, 0.10, 0.15) are synthesized via sol–gel auto-combustion method. The phase formation is examined by ...X-ray diffraction technique which confirms the tetragonal structure of all samples at room temperature. Field Emission Scanning Electron Microscope (FESEM), dielectric, conductivity, impedance and modulus analysis are also carried out to study the morphology and the electrical properties of the ferrites. Dielectric study (
ϵ
r
vs.
T
) confirms the presence of frequency dependent dielectric relaxation peak. The temperature (
T
m
) at which the value of
ϵ
r
is maximum shift towards higher temperature as frequency increases. Dielectric properties have been improved after Ni is doped into Copper ferrite. Both ac and dc conductivity confirms the NTCR behavior in the ferrites. Frequency variation of ac conductivity follows the Jonscher’s power law and the conduction mechanism in the ferrites is well explained by Correlated barrier hopping (CBH) model. Nyquist plot (
Z
′
′
vs.
Z
′
) reveals combine contribution of both bulk and grain boundary effects in the ferrites. DC conductivity (
σ
dc
) and the relaxation time (
τ
) obeys Arrhenius type behavior and the modulus study validates the existence of non-Debye type of relaxation. The detail complex impedance and modulus analysis support the usage of many technological applications. Vibrating Sample Magnetometer (VSM) analyzer shows the soft magnetic nature of as-prepared ferrites and has the potential application towards magnetic storage devices and field sensor. Enhancement of saturation magnetization (
M
S
) is also noticed as Ni content is increased.
•Preparation of bilayer of CoFe2O4/ZnFe2O4 on quartz substrate which results in large magnetization after annealing.•The obtained room temperature magnetization is higher than any binary ferrite and ...is close to metallic Nickel.•The highest magnetic moment value cannot be explained by Néel model.
In this paper, we report our observation of an extraordinarily large value of magnetization in an annealed CoFe2O4/ZnFe2O4 bilayer. Sets of bilayers of CoFe2O4/ZnFe2O4 were deposited at ambient temperature, using pulsed laser deposition setup equipped with Nd: YAG laser, and subsequently annealed in air at different temperatures for 2 h. The highest attained value of magnetization was ≈7200 G at 300 K and ≈15000 G at 10 K for a bilayer with a 60 nm thickness tCo of CoFe2O4 and 40 nm thickness tZn of ZnFe2O4, annealed at 650 °C. This measured magnetization value is the highest for any oxide spinel reported thus far in the literature. The observed value is close to that of metallic Ni and cannot be explained by current theories of magnetism in oxides.
•GaFeO3 and (Ga0.97Nd0.03)(Fe1−xMnx)O3 (where × = 0.01–0.03)are synthesized by ceramic method.•Ferroelectric property is enhanced with the increase of Mn content.•With increase in Mn content Tc ...value has increased from 196.6 K (for GFO) to 202.1 K (for GNFMO2).•Temperature dependent impedance analysis of the sample shows the presence of two relaxation process.
GaFeO3 and (Ga0.97Nd0.03)(Fe1-xMnx)O3 (where × = 0.01–0.03)are synthesized by ceramic method. X-ray diffractometer (XRD), Field Emission Scanning Electron Microscope (FESEM), electrical properties (such as dielectric, impedance, modulus, and conductivity), P-E loop (polarization) and magnetic studies are carried out to investigate the structural, microstructural, electrical and multiferroic properties of the materials. The XRD peaks of all the specimens have pure phases with an orthorhombic crystal structure bearing Pc21n space group as obtained from the Rietveld refinement. Variation of dielectric constant with temperature represents that GaFeO3 and the doped samples exhibits dielectric anomaly well above the room temperature. It is also noticed that transition temperature increases with the increment of Mn content. The complex impedance plot exhibits two semicircles, which represents the presence of bulk and grain boundary effects. The modulus spectroscopy validates the existence of a non-Debye type of relaxation. P-E loop and PUND analysis at room temperature confirms the presence of weak ferroelectricity in the materials. However, ferroelectric property is enhanced with the increase of Mn content.
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