526 research outputs found
Stress analysis of helicopter main rotor torsion bar
The results of stress analysis for the main rotor torsion bar of the ANSAT helicopter based on the finite element method are presented. The analysis was performed for the base types of loading in the linear statement. The analysis results agree well with the experimental data. © Allerton Press, Inc., 2009
Explicit asymptotic modelling of transient Love waves propagated along a thin coating
The official published version can be obtained from the link below.An explicit asymptotic model for transient Love waves is derived from the exact equations of anti-plane elasticity. The perturbation procedure relies upon the slow decay of low-frequency Love waves to approximate the displacement field in the substrate by a power series in the depth coordinate. When appropriate decay conditions are imposed on the series, one obtains a model equation governing the displacement at the interface between the coating and the substrate. Unusually, the model equation contains a term with a pseudo-differential operator. This result is confirmed and interpreted by analysing the exact solution obtained by integral transforms. The performance of the derived model is illustrated by numerical examples.This work is sponsored by the grant from Higher Education of Pakistan and by the Brunel University’s “BRIEF” research award
Remote visual detection of impacts on the lunar surface
We propose a novel method of remotely observing impacts on the airless Moon that may extend the present data base on meteoroids down to 1 m in diameter. Meteorites or comets of radius approximately 1-100 m are burnt away or dispersed in the atmospheres of the Earth and Venus. However, when such objects strike the Moon they deposit their energy in a small initial volume, forming a plasma plume whose visible and infrared radiation may be visible from the Earth. We consider impacts of model SiO2 projectiles on the surface of an SiO2 model Moon
The Structure of Martian Magnetosphere at the Dayside Terminator Region as Observed on MAVEN Spacecraft
We analyzed 44 passes of the MAVEN spacecraft through the magnetosphere,
arranged by the angle between electric field vector and the projection of
spacecraft position radius vector in the YZ plane in MSE coordinate system
( E ). All passes were divided into 3 angular sectors near 0{\deg},
90{\deg} and 180{\deg} E angles in order to estimate the role of IMF
direction in plasma and magnetic properties of dayside Martian magnetosphere.
The time interval chosen was from January 17 through February 4, 2016 when
MAVEN was crossing the dayside magnetosphere at SZA ~ 70{\deg}. Magnetosphere
as the region with prevailing energetic planetary ions is always found between
the magnetosheath and the ionosphere. 3 angular sectors of dayside interaction
region in MSE coordinate system with different orientation of the solar wind
electric field vector E = -1/c V x B showed that for each sector one can find
specific profiles of the magnetosheath, the magnetic barrier and the
magnetosphere. Plume ions originate in the northern MSE sector where motion
electric field is directed from the planet. This electric field ejects
magnetospheric ions leading to dilution of magnetospheric heavy ions
population, and this effect is seen in some magnetospheric profiles. Magnetic
barrier forms in front of the magnetosphere, and relative magnetic field
magnitudes in these two domains vary. The average height of the boundary with
ionosphere is ~530 km and the average height of the magnetopause is ~730 km. We
discuss the implications of the observed magnetosphere structure to the
planetary ions loss mechanism.Comment: 24 pages, 13 figure
Observation of a Chiral State in a Microwave Cavity
A microwave experiment has been realized to measure the phase difference of
the oscillating electric field at two points inside the cavity. The technique
has been applied to a dissipative resonator which exhibits a singularity --
called exceptional point -- in its eigenvalue and eigenvector spectrum. At the
singularity, two modes coalesce with a phase difference of We
conclude that the state excited at the singularity has a definitiv chirality.Comment: RevTex 4, 5 figure
К 85-летию со дня рождения Ивана Никандровича Шестова
The information on activity of the Chair of the Dynamic Geology and Hydrogeology Department of the Perm State University, Dr. I.N. Shestov is presented.Приведены сведения о деятельности кандидата геолого-минералогических наук, доцента кафедры динамической геологии и гидрогеологии Пермского государственного национального исследовательского университета Ивана Никандровича Шестова
Enabling magnetic resonance imaging of hollow-core microstructured optical fibers via nanocomposite coating
Optical fibers are widely used in bioimaging systems as flexible endoscopes
capable of low-invasive penetration inside hollow tissue cavities. Here, we
report on the technique which allows magnetic resonance imaging (MRI) of
hollow-core microstructured fibers (HC-MFs), paving the way for combing MRI and
optical bioimaging. Our approach is based on Layer-by-Layer assembly of
oppositely charged polyelectrolytes and magnetite nanoparticles on the inner
core surface of HC-MFs. Incorporation of magnetite nanoparticles into
polyelectrolyte layers renders HC-MFs visible for MRI and induces the red-shift
in their transmission spectra. Specifically, the transmission shifts up to 60
nm have been revealed for the several-layers composite coating along with the
high-quality contrast of HC-MFs in MRI scans. Our results shed light on
marrying fiber-based endoscopy with MRI that opens novel possibilities for
minimally invasive clinical diagnostics and surgical procedures in vivo.Comment: 11 pages, 6 figure
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