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Wyszukujesz frazę "R41" wg kryterium: Wszystkie pola


Tytuł:
Near Magnetic Field of a Small Turbojet Engine
Autorzy:
Andoga, R.
Főző, L.
Powiązania:
https://bibliotekanauki.pl/articles/1030273.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.-q
Opis:
Different parameters like temperatures, pressures, speed, and vibrations are used in evaluation of technical state of turbojet engines. The article presents a pioneering idea to expand this set of parameters with measurements of distortions in magnetic field in a close vicinity of the engine to obtain more information about its state, which can be further used in its diagnostic and control systems. We believe that deviations in near magnetic field can hold valuable information, which can be used to predict malfunctions and evaluate the condition of the engine. The presented article shows pilot experimental results and gives answer to the basic hypothesis, if such measurements can be realized using a small turbojet engine, as well if there are significant changes in near magnetic field, which would warrant further research in the area.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1117-1119
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
TE Surface Waves in a Plasma Sandwich Structure
Autorzy:
Shaikh, M.
Zamir, B.
Ali, R.
Powiązania:
https://bibliotekanauki.pl/articles/1189881.pdf
Data publikacji:
2015-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
84.40.Az
Opis:
Transverse electric surface waves are analyzed in a plasma medium bounded by a left-handed material. A dispersion relation is obtained by applying the boundary conditions for the tangential field components. Numerical investigations show the dependence of effective wave index on the propagation frequency for different thicknesses and number densities of the plasma medium and also for different values of the filling factor of left-handed material.
Źródło:
Acta Physica Polonica A; 2015, 127, 6; 1625-1629
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experience Gained during the Decommissioning of the SSEC from the VVR-S Nuclear Research Reactor
Autorzy:
Deju, R.
Iorga, I.
Gurau, D.
Powiązania:
https://bibliotekanauki.pl/articles/1033371.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
28.41.Te
Opis:
The VVR-S nuclear research reactor owned by Horia Hubulei National Institute of Physics and Nuclear Engineering was designed for research and radioisotope production being permanently shut-down in 2002 after 40 years of operation. The decommissioning of the reactor started in 2010 and is planned to be finalized in 2020, being the first nuclear research reactor that has started the decommissioning project from the South-East of Europe. This paper presents the lessons learned from the decommissioning of systems, structures, equipment and components from pumps room. The experiences gained cover a diverse range of topics from planning, approval, radiological characterization process made, dismantling, equipment used, resources, etc. Radiation protection and economics are the key factors for the selection of technology for decommissioning. The evaluation of the available technology has been made and areas for improving the technology have been identified. Dedicated and advanced technologies were chosen to perform specific tasks. The project was planned well in advance. Safety aspects have been taken into consideration. Resource constraints have also been an important issue considered in defining the decommissioning strategy. Experiences and knowledge were presented and shared with the community.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 82-88
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Confined Metamaterial Structures Based on Coordinate Transformations
Autorzy:
Vasić, B.
Gajić, R.
Isić, G.
Hingerl, K.
Powiązania:
https://bibliotekanauki.pl/articles/1807844.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.50.De
41.20.Jb
42.70.-a
Opis:
We apply transformation optics to structures in which the electromagnetic field is confined by highly conducting coatings. The possibility of changing the field propagation direction without perturbation is demonstrated on the example of a waveguide bend. Using this approach it is also possible to reshape a confined structure in order to meet certain external requirements and to redistribute a field in order to obtain desired field distribution. The structure implementation implies replacing a part of given confined structure with a metamaterial designed using the technique of transformation optics. Simplification of structure realization based on using reduced set of material parameters is examined. Our theoretical considerations are confirmed by full wave finite element simulations of a waveguide bend.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 96-98
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Shielding Effectiveness of a Magnetic Fluid in Radio Frequency Range
Autorzy:
Dolník, B.
Rajňák, M.
Cimbala, R.
Kolcunová, I.
Kurimský, J.
Džmura, J.
Petráš, J.
Zbojovský, J.
Kosterec, M.
Kopčanský, P.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030481.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
41.20.Gz
75.50.Mm
81.70.Ex
07.50.Hp
Opis:
This article builds on the previous work and describes the interaction of transformer oil-based magnetic fluid (MF) with the radio frequency (RF) magnetic near-field. Three prepared samples of the MF used as a barrier to magnetic near-field, consist of transformer oil and dispersed magnetite nanoparticles coated with oleic acid. We pay attention to the important area related to the electromagnetic field shielding by the MF. Such sample of the MF may be a good candidate for applications where it is necessary to simultaneously electrically isolate, remove the excess of heat and to shield electromagnetic interference (EMI). We present a method for the determination of shielding effectiveness (SE) of the MF under RF excitation conditions ranging from 500 MHz to 3 GHz. We report the effect of magnetic volume fraction in the MF and the effect of the sample thickness on the SE.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 585-587
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Imperfect Cloaking Devices Based on Metamaterials
Autorzy:
Isić, G.
Gajić, R.
Novaković, B.
Popović, Z. V.
Hingerl, K.
Powiązania:
https://bibliotekanauki.pl/articles/2047887.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
42.25.Fx
78.20.Ci
Opis:
Cloaking devices designed using the coordinate transform approach were shown to be realizable, at least in principle, within the realm of electromagnetic metamaterials. In this paper we investigate the strictness of conditions imposed on the parameters of metamaterial cloaks by calculating the degree of wave scattering when those parameters have variations with respect to theoretically ideal values. A simple idea is used to obtain analytic results for the case of the nonideal two-dimensional cloaking cylinder. Also, results of realistic finite element simulations of the Helmholtz equation are presented and it is found that they are in excellent agreement with the analytic results.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 1083-1088
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutron Shielding Properties of Concrete and Ferro-Boron
Autorzy:
Sarıyer, D.
Küçer, R.
Küçer, N.
Powiązania:
https://bibliotekanauki.pl/articles/1401975.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.Uu
28.41.Qb
87.52.-g
87.52.Ga
Opis:
The problem of shielding against high-energy neutrons has always attracted a great deal of attention. Neutron shielding requires slowing down energetic neutrons and absorbing with a shield material. Concrete is one of the best known materials for neutron shielding and ferro-boron is described as an alternative shielding material in this study. FLUKA Monte Carlo simulation code was used for the application of shielding calculation. When the simulation results are compared, it is clear that ferro-boron is more effective in neutron shielding than the concrete.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-201-B-202
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Response of a Magnetic Fluid to Radio Frequency Electromagnetic Field
Autorzy:
Dolník, B.
Rajňák, M.
Cimbala, R.
Kolcunová, I.
Kurimský, J.
Balogh, J.
Džmura, J.
Petráš, J.
Kopčanský, P.
Timko, M.
Briančin, J.
Fabián, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032825.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
41.20.Gz
75.50.Mm
81.70.Ex
07.50.Hp
Opis:
Electromagnetic pollution generated by the electrical devices has been regarded as a new form of pollution, harmful to the society as air and water pollution. The operation of electronic devices in a polluted electromagnetic environment has caused electromagnetic interference to become important concerns. Devices that are vulnerable to interference must often be shielded to protect them from the effects of electromagnetic interference. In this work we describe an interaction of a magnetic fluid based on transformer oil with alternating magnetic field. The magnetic fluid was composed of a transformer oil and dispersed magnetite nanoparticles coated with oleic acid. Among the wide range of topics covered, we pay attention to an important field related to the absorption of electromagnetic field by magnetic fluid as a suitable candidate for applications where it is necessary to electrically isolate, remove excess of heat, and to shield electromagnetic fields. We present a method for the determination of shielding effectiveness of the magnetic fluid under high-frequency excitation conditions from 750 MHz to 3 GHz by means of magnetic near field measurements and analysis. Herein, we report the effect of magnetic volume fraction in the magnetic fluid and the effect of the sample thickness on the shielding effectiveness. We have found that the magnetic fluid has a frequency dependent "windows", characterized that either absorb the magnetic field, or facilitate penetration of the magnetic field through the barrier.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 946-948
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimized Frequency Selective Surface for the Design of Magnetic Type Thin Broadband Radio Absorbers
Autorzy:
Babayan, V.
Kazantseva, N.
Kazantsev, Yu.
Vilčáková, J.
Moučka, R.
Powiązania:
https://bibliotekanauki.pl/articles/1032283.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.-q
Opis:
A novel frequency selective surface for expansion of operating frequency range of magnetic-type radio absorbers was elaborated. Frequency selective surface represents an array of flat electrically conductive elements deposited on the polyethylene terephthalate (PET) foil. The elements have a closed-loop structure on the one side of the foil, and on the opposite side, the conductive elements have the shape of solid fragments which connect projections of the neighboring closed loops. The advantage of such frequency selective surface design is that owing to capacitive shunting one can achieve the value of frequency selective surface quality factor (Q-factor) as low as 0.5. Operating frequency range and thickness of designed radio absorbers depend on the composition of polymer-magnetic material and the position of frequency selective surface therein.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1147-1149
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Outdoor Ageing of an Ethylene-Propylene Copolymer: A Positron Annihilation Study
Autorzy:
Consolati, G.
Quasso, F.
Gallo, R.
Severini, F.
Powiązania:
https://bibliotekanauki.pl/articles/2043322.pdf
Data publikacji:
2005-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
78.70.Bj
81.05.Lg
Opis:
An investigation on the environmental degradation of an ethylene-propylene copolymer was carried out through positron annihilation lifetime spectroscopy, density and differential scanning calorimetry measurements. Polymer sheets were exposed to sunlight up to 11000 hours. Density and melting enthalpy increase with ageing, while ortho-positronium intensity decreases; ortho-positronium lifetime does not show significant variations up to 4400 hours. At higher exposures it starts to decrease. Outdoor ageing produces an increased crystallinity of the copolymer; also a degradation occurs with formation of carbonyl groups. The corresponding Ps inhibition is the main reason for the decrease in ortho-positronium intensity, the other one being the reduced amount of the amorphous phase available. The lifetime decrease observed at the highest exposures can be interpreted in terms of a shrinking of the nanoholes trapping positronium.
Źródło:
Acta Physica Polonica A; 2005, 107, 5; 805-810
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Porosimetry Studies of Template Removal from As-Synthesized MCM-41 Silica
Autorzy:
Zaleski, R.
Wawryszczuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812554.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
36.10.Dr
61.43.Gt
81.07.-b
Opis:
The course of template removal from MCM-41 pores was investigated by positron annihilation lifetime spectroscopy. Two methods of removal were the object of interest: a decarbonisation after standard calcination procedure and a novel procedure - pyrolysis in vacuum. The shapes of positron lifetime spectra of decarbonised sample are determined by positronium quenching caused by presence of carbon deposit on the surface. Positron annihilation lifetime spectroscopy allows also monitoring the evolution of empty space inside pores. During pyrolysis no conductive carbon is produced, so consecutive stages of template material transformation are easy to observe. In the case of pyrolysis the effect of pore emptying is obtained at temperature 500 K, lower comparing to calcination and decarbonisation (820 K).
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1543-1550
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a Soft X-ray Microprobe for Radiobiology Studies
Autorzy:
Appuhamilage, I.
Adjei, D.
Alatabi, S.
Alnaimi, R.
Michette, A.
Pfauntsch, S.
Powiązania:
https://bibliotekanauki.pl/articles/1197646.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.50.+h
07.85.Fv
Opis:
The King's College London (KCL) first X-ray microprobe (MKI) and the third generation microfocus X-ray sources (MKIII) are intended to be used for various applications including the study of physical and biological interactions at the atomic and molecular scales. The microfocus ultra-soft X-ray sources (MKI and MKIII) with interchangeable targets will provide a superior spatial resolution (a focal spot a few hundreds of nanometres in diameter can be achieved) and the control of the dose delivered to irradiated cells. This will require characterization of the spectra and intensities of the source, measurements of the focus intensities and spot sizes of suitable X-ray optics such as zone plates, grazing incidence microstructured optical arrays and multilayer mirrors.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 882-885
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of Operational Radioprotection Simulation in the Dismantling of the Protection and Control Rods of VVR-S Reactor
Autorzy:
Iorga, I.
Deju, R.
Gurau, D.
Mincu, M.
Powiązania:
https://bibliotekanauki.pl/articles/1033535.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
28.41.Te
Opis:
The VVR-S nuclear research reactor owned by Horia Hubulei National Institute of Physics and Nuclear Engineering, has functioned between 1957 and 1997 at a nominal thermal power of 2 MW, using less-enriched nuclear fuel (10%), type EK-10, and highly enriched fuel (36%), type S-36. The reactor control was carried out by means of nine rods placed in the central part of the core. Four rods were used for the manual control of power, one for automatic control, three rods for reactor safety (emergency rods) and one for the fine control of power. One of the high hazard operations was the dismantling of the activated-contaminated control rods. Because of a higher radiological risk, simulation was performed to determine the expected maximum dose. The maximum gamma dose rate obtained using simulated results was 3.5 Sv/h, for the highly activated rod. In the real measurement, when the work was performed, the maximum gamma dose rate was 3 Sv/h. ⁹⁰Sr+⁹⁰Y are expected to be present in the control rods radioactivity.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 514-518
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement and Analysis of the Positron Annihilation Lifetime Spectra for Mesoporous Silica
Autorzy:
Zaleski, R.
Powiązania:
https://bibliotekanauki.pl/articles/2047164.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
36.10.Dr
61.43.Gt
81.07.-b
41.75.Fr
Opis:
Positron annihilation lifetime spectroscopy as a technique of porous materials investigation is still under development. Both measurement conditions and lifetime spectra analysis methods have to be adapted to the requirements of positron porosimetry. If complex positron annihilation lifetime spectra of porous materials are processed, numerical methods of lifetime spectra analysis have to be used with a particular care. Among various methods of positron annihilation lifetime spectra analysis available, the most popular ones were tested implemented in programs MELT and LT. It was found, from the simulated spectra study, that a large number of counts in a spectrum is needed to obtain reliable results of analysis. Even then only an approximate solution is available. Determination of the approximation nature helps in a further interpretation of the results and in positron annihilation lifetime spectrometer setting adequate to the problem. For this purpose, a few complex spectra obtained from positron beam facility were tested. The results show a negligible influence of resolution function on long lifetime components, while the precise estimation of the background level is crucial. Also some distortions caused by imperfection of numerical analysis methods are pointed out.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 729-738
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Two-Dimensional Photonic Crystal Microcavities as a Function of Refractive Index
Autorzy:
Moukhtari, R.
Hocini, A.
Khedrouche, D.
Powiązania:
https://bibliotekanauki.pl/articles/1398722.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Qs
04.30.Nk
41.20.Jb
42.82.-m
Opis:
Quality factor of two-dimensional photonic crystals microcavity fabricated by SiO₂/ZrO₂ or SiO₂/TiO₂ in which the refractive index varied in the range of 1.51 to 1.58 has been investigated in the present paper. The structure studied consists of circular rods of radius r embedded in air slab, while a is the constant of triangular lattice. Finite difference time domain method with perfectly matched layers was used to calculate the transmission spectrum by FullWAVE software. The results of simulation clearly demonstrate the existences of resonance wavelength of which the position and the highest Q (Q ≈ 4×10⁵) value are strongly affected by refractive index. We demonstrate that the calculated Q factor for the designed cavity increases by a factor of three relative for a cavity without increasing the refractive index.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 556-558
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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