Planar hyper-lens with uniform pre-designed magnification factor by homogeneous medium

This study deals with a methodology for increasing the efficiency of dynamic process calculations in elastic elements of complex engineering constructions. We studied the complex dynamic processes in a simple engineering construction, a mechanical system of an elastic body–continuous flow of homogeneous medium. The developed methodology is based on the use of a priori information on some of the vibrations forms, the construction of a “simplified” mathematical model of system dynamics, and the obtaining of an analytical relationship that describe the overall range of factors on the elastic vibrations of system. The methodology is used for cases of complex vibrations of elastic bodies, and the obtained results can serve as a basis for choosing the main technological and operational parameters of elastic elements of mechanisms and machines that perform complex vibrations. The results obtained in this work are the basis for calculating the blast effect on the elements of protective structures in order to increase their protective capacity by improving the method of their attachment or by using additional reinforcement, buff load effects on the elements of drilling strings and dynamic processes that occur during surface strengthening by work hardening in order to avoid resonance phenomena, and technological processes of vibration displacement or vibration separation of granular media.

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A Critical Note on the Engineering Model of Radiating Antenna in Homogeneous Medium: Field Regions and Transition Zone Boundaries

IEEE Electromagnetic Compatibility Magazine ◽

10.1109/memc.2021.9400993 ◽

2021 ◽

Vol 10 (1) ◽

pp. 41-50

Author(s):

Anatoly Tsaliovich ◽

Motti Haridim ◽

Jacob Gavan

Keyword(s):

Transition Zone ◽

Homogeneous Medium ◽

Engineering Model ◽

Critical Note

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Effects of supernovae feedback and black hole outflows in the evolution of Dwarf Spheroidal Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s174392132000215x ◽

2020 ◽

Vol 15 (S359) ◽

pp. 280-282

Author(s):

Gustavo Amaral Lanfranchi ◽

Anderson Caproni ◽

Jennifer F. Soares ◽

Larissa S. de Oliveira

Keyword(s):

Black Hole ◽

Homogeneous Medium ◽

Massive Black Hole ◽

Dwarf Spheroidal Galaxies ◽

Stellar Feedback ◽

Gas Removal ◽

The Galaxy ◽

Main Driver ◽

Ia Supernovae ◽

Jet Structure

AbstractThe gas evolution of a typical Dwarf Spheroidal Galaxy is investigated by means of 3D hydrodynamic simulations, taking into account the feedback of type II and Ia supernovae, the outflow of an Intermediate Massive Black Hole (IMBH) and a static cored dark matter potential. When the IMBH’s outflow is simulated in an homogeneous medium a jet structure is created and a small fraction of the gas is pushed away from the galaxy. No jet structure can be seen, however, when the medium is disturbed by supernovae, but gas is still pushed away. In this case, the main driver of the gas removal are the supernovae. The interplay between the stellar feedback and the IMBH’s outflow should be taken into account.

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Superfluid vortex-mediated mutual friction in non-homogeneous neutron star interiors

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3097 ◽

2020 ◽

Vol 499 (3) ◽

pp. 3690-3705

Author(s):

M Antonelli ◽

B Haskell

Keyword(s):

Neutron Star ◽

Normal Component ◽

Homogeneous Medium ◽

Outer Core ◽

Two Dimensions ◽

Pinning Force ◽

Mutual Friction ◽

Momentum Exchange ◽

Drag Forces ◽

Vortex Lines

ABSTRACT Understanding the average motion of a multitude of superfluid vortices in the interior of a neutron star is a key ingredient for most theories of pulsar glitches. In this paper, we propose a kinetic approach to compute the mutual friction force that is responsible for the momentum exchange between the normal and superfluid components in a neutron star, where the mutual friction is extracted from a suitable average over the motion of many vortex lines. As a first step towards a better modelling of the repinning and depinning processes of many vortex lines in a neutron star, we consider here only straight and non-interacting vortices: we adopt a minimal model for the dynamics of an ensemble of point vortices in two dimensions immersed in a non-homogeneous medium that acts as a pinning landscape. Since the degree of disorder in the inner crust or outer core of a neutron star is unknown, we compare the two possible scenarios of periodic and disordered pinscapes. This approach allows us to extract the mutual friction between the superfluid and the normal component in the star when, in addition to the usual Magnus and drag forces acting on vortex lines, also a pinning force is at work. The effect of disorder on the depinning transition is also discussed.

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Giant refractometric sensitivity by combining extreme optical Vernier effect and modal interference

Scientific Reports ◽

10.1038/s41598-020-76324-7 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

André D. Gomes ◽

Jens Kobelke ◽

Jörg Bierlich ◽

Jan Dellith ◽

Manfred Rothhardt ◽

...

Keyword(s):

State Of The Art ◽

Single Mode ◽

High Magnification ◽

Magnification Factor ◽

Detection Systems ◽

Current State ◽

Modal Interference ◽

Vernier Effect ◽

Index Unit ◽

Conventional Detection

Abstract The optical Vernier effect consists of overlapping responses of a sensing and a reference interferometer with slightly shifted interferometric frequencies. The beating modulation thus generated presents high magnified sensitivity and resolution compared to the sensing interferometer, if the two interferometers are slightly out of tune with each other. However, the outcome of such a condition is a large beating modulation, immeasurable by conventional detection systems due to practical limitations of the usable spectral range. We propose a method to surpass this limitation by using a few-mode sensing interferometer instead of a single-mode one. The overlap response of the different modes produces a measurable envelope, whilst preserving an extremely high magnification factor, an order of magnification higher than current state-of-the-art performances. Furthermore, we demonstrate the application of that method in the development of a giant sensitivity fibre refractometer with a sensitivity of around 500 µm/RIU (refractive index unit) and with a magnification factor over 850.

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