Physics

Instability of Plane Poiseuille Flow in Viscous Compressible Gas
Instability of plane Poiseuille flow in viscous compressible gas is investigated. A condition for the Reynolds and Mach numbers is given in order for plane Poiseuille flow to be unstable. It turns out that plane Poiseuille flow is unstable for Reynolds numbers much less than the critical Reynolds number for the incompressible flow when the Mach number is suitably large. It is proved by the anal...


Biogasoline: An out-of-the-box solution to the food-for-fuel and land-use competitions
Societal developments are hinged on the energy supplied by fossil fuels. However, the supply of these fuels is finite in the foreseeable future. This is aside the associated environmental degradation and economic sustainability of these fuels. These negative consequences and challenges spurred the search for sustainable energy sources such as biofuels. However, affordable feedstocks and efficie...
Study on the matching performance of a low temperature reverse Brayton air refrigerator
A small reverse Brayton cycle air refrigerator was designed and fabricated. Bump-type air journal foil bearing, pressurized thrust gas bearing and centrifugal blower as brake were employed in the turboexpander. Usually, constant brake inlet pressure is set in a reverse Brayton refrigerator. However, the unchanged brake inlet pressure cannot adapt to the changing temperature and expansion ratio ...


Air blast reflecting on a rigid cylinder: simulation and reduced scale experiments
In this paper, the Multi-Material ALE formulation is applied to simulate the propagation of an air blast through the atmosphere, and its reflection on an assumed rigid cylindrical obstacle. The mathematical and numerical implementations of this formulation are presented. In order to validate the formulation and prove its ability to capture the propagation and reflection of high pressure waves, ...
Raman spectroscopy analysis of lipid droplets content, distribution and saturation level in Non-Alcoholic Fatty Liver Disease in mice
Non-Alcoholic Fatty Liver Disease (NAFLD) is a common liver disorder, characterized by an excessive lipids deposition within the hepatic tissue. Due to the lack of clear-cut symptoms and optimal diagnostic method, the actual prevalence of NAFLD and its pathogenesis remains unclear, especially in the early stages of progression. In the presented work confocal Raman microspectroscopy was used to ...


Characterisation of the triumf neutron facility using a monte carlo simulation code
Here, the characterisation of the high-energy neutron field at TRIUMF (The Tri Universities Meson Facility, Vancouver, British Columbia) with Monte Carlo simulation software is described. The package used is MCNPX version 2.6.0, with the neutron fluence rate determined at three locations within the TRIUMF Thermal Neutron Facility (TNF), including the exit of the neutron channel where users of t...
Implementation of the new international standards in swiss legislation on radon protection in dwellings
The current revision of the Swiss Radiological Protection Ordinance aims to bring Swiss legislation in line with new international standards. In future, the control of radon exposure in dwellings will be based on a reference level of 300 Bq m–3. Since this value is exceeded in >10 % of the buildings so far investigated nationwide, the new strategy requires the development of efficient mea...

Interstitial H + -Mediated Ferromagnetism in Co-Doped ZnS
The ferromagnetic mediation centers of enough high concentration are the prerequisites for the realization of ferromagnetic diluted magnetic semiconductors. Zn0.97Co0.03S ultrafine nanoparticles of diameter ˜4 nm with zinc blende structure were synthesized by the chemical coprecipitation method. After annealing in H2 atmosphere at 500 °C for 2 h, Zn0.97Co0.03S transformed to wurtzite structur...
Simulation of Magnetotransport Properties of Ferromagnetic/Antiferromagnetic Multilayers of Manganites
In this work, magnetic and magnetotransport properties of ferromagnetic (FM)/antiferromagnetic (AF) (La2/3Ca1/3MnO3/La1/3Ca2/3MnO3)n (n = 1, 3, 5, 8) manganite multilayers using the standard Monte Carlo method were studied. Simulations of a three-dimensional classical Heisenberg model implemented with a single spin-flip Metropolis dynamics were performed. The Hamiltonian included four different...

Effect of Annealing Temperature and Boron Addition on Magnetic Properties of Hexaferrites Synthesized by Standard Ceramic Method
The barium and strontium hexaferrites (BaM and SrM) were successfully prepared by the standard solid-state reaction method. To inhibit crystal growth, 1 wt % B2O3 was added into the initial mixture. The structural and magnetic properties of pure hexaferrites were compared with the samples prepared with boron addition. Powders were annealed at temperatures between 800 and 1200 ∘C. The crystal ...
Cube Texture Formation in Fe–50 % Ni Thin Tapes Under Annealing in DC High Magnetic Field
The main purpose of the work is to study the recovery and recrystallization processes in cold-rolled tapes of the Ni48.8Fe51.2 alloy subjected annealing under high magnetic fields up to 20T. In the course of primary recrystallization without magnetic field, in the tapes made of this alloy, there forms a sufficiently sharp cube texture, which makes it possible to use these tapes for epitaxial de...

Spontaneous Appearance of the Spin-Triplet Fulde-Ferrell-Larkin-Ovchinnikov Phase in a Two-Band Model: Possible Application to LaFeAsO 1−x F x
The possibility of a spontaneous spin-triplet paired phase of the Fulde-Ferrell-Larkin-Ovchinnikov type is studied. As it is shown in a system with the dominant interband pairing and two distinct Fermi surface sheets, the Fermi wave-vector mismatch can be compensated by a nonzero center-of-mass momentum of the Cooper pairs. This idea is examined with the use of a model which describes the two h...
Graphene folding on flat substrates
We present a combined experimental-theoretical study of graphene folding on flat substrates. The structure and deformation of the folded graphene sheet are experimentally characterized by atomic force microscopy. The local graphene folding behaviors are interpreted based on nonlinear continuum mechanics modeling and molecular dynamics simulations. Our study on self-folding of a trilayergraphene...
Design of 4-electrode optical device for application of vector electric fields to self-assembled quantum dot complexes
Self-assembledInAsquantum dots(QDs) are of great interest as components of optoelectronic devices that can operate at the quantum limit. The charge configuration, interdot coupling, and symmetry of complexes containing multiple QDs can all be tuned with applied electric fields, but the magnitude and angle of the electric field required to control each of these parameters depend on the orientati...
Irreversibility fields and critical current densities in strongly pinned YBa2Cu3O7-x films with BaSnO3 nanorods: The influence of segmented BaSnO3 nanorods
We report irreversibility fields Birr and critical current densities Jc in YBa2Cu3O7-x thin films containing segmented BaSnO3nanorods. Birr and Jc are systematically changed by selection of nanorod length and its spacing, and the variations are explained by the “harmonic oscillator” approach based on the Bose glass state. Analysis of pinning energies and Jc indicates that segmented nanorods...