91 research outputs found
Dynamic analysis of spur gear with backlash using ADAMS
Gear tooth profile can deviate from its initial design shape and size as a result of increasing service time under time-varying load, introducing external agents like debris, overheating due to friction, wear, and in generally due to other nonlinear factors such as backlash. As a result, the dynamics of the gear will also vary depending on the resulting gear tooth profile. In this study, the worn-out gear tooth is modelled as a backlash by assuming a uniformly distributed worn out surface and the effect on the dynamic performance is investigated. By changing the amount of backlash of the gear tooth from 0 mm to 1 mm by 0.2 mm increment, the gear is modelled and analysed for three loading cases using MSC ADAMS software. This paper discusses the effect of backlash or uniformly worn out spur gear tooth faces on the dynamics specifically the contact and angular accelerations of the gear.publishedVersio
Contact temperature analysis of the classical Geneva mechanism through numerical methods
In this study, the flash temperature of the classical Geneva mechanism has been studied using the numer-
ical method. An excessive sliding motion between the wheel and pin leads to the generation of heat at the
contact surfaces, which raises the surface temperature of the two contacting bodies. The flash tempera-
ture has been anticipated for different loading cases and coefficients of friction. The analytical Blok equa-
tion results are compared with the finite element results, and the results are satisfactory for maximum
temperature. Based on the simulation results, the maximum contact temperature occurred in the driving
crankpin within 10-15° and 70–75° of the angular position, and as the load increased the contact temper-
ature also increases. In addition, the angular velocity increment produced higher temperatures than the torque load increments.publishedVersio
Magnetic Structure in Fe/Sm-Co Exchange Spring Bilayers with Intermixed Interfaces
The depth profile of the intrinsic magnetic properties in an Fe/Sm-Co bilayer
fabricated under nearly optimal spring-magnet conditions was determined by
complementary studies of polarized neutron reflectometry and micromagnetic
simulations. We found that at the Fe/Sm-Co interface the magnetic properties
change gradually at the length scale of 8 nm. In this intermixed interfacial
region, the saturation magnetization and magnetic anisotropy are lower and the
exchange stiffness is higher than values estimated from the model based on a
mixture of Fe and Sm-Co phases. Therefore, the intermixed interface yields
superior exchange coupling between the Fe and Sm-Co layers, but at the cost of
average magnetization.Comment: 16 pages, 6 figures and 1 tabl
Driven lattice glass as a ratchet and pawl machine
Boundary-induced transport in particle systems with anomalous diffusion
exhibits rectification, negative resistance, and hysteresis phenomena depending
on the way the drive acts on the boundary. The solvable case of a 1D system
characterized by a power-law diffusion coefficient and coupled to two particles
reservoirs at different chemical potential is examined. In particular, it is
shown that a microscopic realisation of such a diffusion model is provided by a
3D driven lattice-gas with kinetic constraints, in which energy barriers are
absent and the local microscopic reversibility holds.Comment: 12 pages, 4 figures, minor change
Highly Tunable Intrinsic Exchange Bias from Interfacial Reconstruction in Epitaxial NixCoyFe3-x-yO4(111)/{\alpha}-Al2O3(0001) Thin Films
Intrinsic exchange bias up to 12.6 kOe is observed in
NixCoyFe3-x-yO4(111)/{\alpha}-Al2O3(0001) (0<=x+y<=3) epitaxial thin films
where 0.15<=y<=2. An interfacial layer of rock-salt structure emerges between
NixCoyFe3-x-yO4 thin films and {\alpha}-Al2O3 substrates and is proposed as the
antiferromagnetic layer unidirectionally coupled with ferrimagnetic
NixCoyFe3-x-yO4. In NiCo2O4(111)/{\alpha}-Al2O3(0001) films, results of
reflection high energy electron diffraction, X-ray photoelectron spectroscopy,
X-ray reflectometry, and polarized neutron reflectometry support that the
interfacial layer is antiferromagnetic NixCo1-xO (0.32<=x<=0.49) of rock-salt
structure; the interfacial layer and exchange bias can be controlled by growth
oxygen pressure revealing the key role of oxygen in the mechanism of the
interfacial reconstruction. This work establishes a family of intrinsic
exchange bias materials with great tunability by stoichiometry and growth
parameters and emphasizes the strategy of interface engineering in controlling
material functionalities.Comment: Main Text: 14 pages, 5 figures; Supplemental Materials: 12 pages, 11
figure
Discovery of a high-temperature antiferromagnetic state and transport signatures of exchange interactions in a Bi2Se3/EuSe heterostructure
Spatial confinement of electronic topological surface states (TSS) in
topological insulators poses a formidable challenge because TSS are protected
by time-reversal symmetry. In previous works formation of a gap in the
electronic spectrum of TSS has been successfully demonstrated in topological
insulator/magnetic material heterostructures, where ferromagnetic exchange
interactions locally lifts the time-reversal symmetry. Here we report an
experimental evidence of exchange interaction between a topological insulator
Bi2Se3 and a magnetic insulator EuSe. Spin-polarized neutron reflectometry
reveals a reduction of the in-plane magnetic susceptibility within a 2 nm
interfacial layer of EuSe, and the combination of SQUID magnetometry and Hall
measurements points to the formation of an antiferromagnetic layer with at
least five-fold enhancement of N\'eel's temperature. Abrupt resistance changes
in high magnetic fields indicate interfacial exchange coupling that affects
transport in a TSS. High temperature local control of TSS with zero net
magnetization unlocks new opportunities for the design of electronic,
spintronic and quantum computation devices, ranging from quantization of Hall
conductance in zero fields to spatial localization of non-Abelian excitations
in superconducting topological qubits
Magnetic proximity-induced energy gap of topological surface states
Topological crystalline insulator surface states can acquire an energy gap
when time reversal symmetry is broken by interfacing with a magnetic insulator.
Such hybrid topological-magnetic insulator structures can be used to generate
novel anomalous Hall effects and to control the magnetic state of the insulator
in a spintronic device. In this work, the energy gap of topological surface
states in proximity with a magnetic insulator is measured using Landau level
spectroscopy. The measurements are carried out on Pb1-xSnxSe/EuSe
heterostructures grown by molecular beam epitaxy exhibiting record mobility and
a low Fermi energy enabling this measurement. We find an energy gap that does
not exceed 20meV and we show that is due to the combined effect of quantum
confinement and magnetic proximity. The presence of magnetism at the interface
is confirmed by magnetometry and neutron reflectivity. The recovered energy gap
sets an upper limit for the Fermi level needed to observe the quantized
anomalous Hall effect using magnetic proximity heterostructures
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