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Effectiveness of Absorbing Microwaves by the Multimaterial Sodium Silicate Base Sand - PLA (Polylactide) Mould Wall Systems

Stachowicz Mateusz

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

30--37

EN

In the paper presented are results of a research on effectiveness of absorbing electromagnetic waves at frequency 2.45 GHz by unhardened sodium silicate base sands (SSBS) prepared of high-silica base sand and a PLA (Polylactide) 3D-prited (3DP) mould walls. Measurements of power loss of microwave radiation (Pin) expressed by a total of absorbed power (Pabs), output power (Pout) and reflected power (Pref) were carried-out on a stand of semiautomatic microwave slot line for determining balance of microwave power emitted into selected multimaterial systems. Values of microwave power loss in the rectangular waveguide filled with unhardened moulding sands and prepared by fused deposition modelling (FDM) 5 mm polylactide (PLA) walls with grid infill density from 25% to c.a. 100% served for determining effectiveness of microwave heating. Balance of microwave power loss is of technological importance for microwave manufacture of high quality casting sand moulds and cores in possibility of use 3D-printed mould tools and core boxes. It was found that apparent density of SSBS placed in a waveguide with PLA walls influences parameters of power output (Pout) and power reflected (Pref). The PLA wall position and grid infill density were identified to have a limited effect on effectiveness of absorbing microwaves (Pabs).

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Fabrication and characterization of iron coated carbon nanotubes/polymer composite for microwave absorption

Kaur Gurjit, Deep Aul Gagan

Composites Theory and Practice

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2020

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R. 20, nr 3-4

111--117

EN

Electrical characteristics of iron coated multi-walled carbon nanotubes (MWNTs) along with ferromagnetic properties are very interesting nanomaterial for microwave absorption. In this research work, surface morphology, compositions and microwave absorption properties of polymer containing iron coated MWNTs have been investigated. Iron coated multi-walled carbon nanotubes composite were prepared by two simple steps method. In addition, microstructure and microwave absorption properties under frequency range 8÷13 GHz by means of FESEM, EDX &Vector network analyzer had shown. The maximum reflection loss is observed for Fe-coated MWNTs/polymer sample B is –20.86 dB and –18.13 dB at frequency 8.1 and 10.75 GHz respectively. And the maximum bandwidth window is available for sample C is 3.25 GHz from frequency 8.45 to 11.7 GHz with 3 mm thickness, which can be attributed to synergistic effect of improved impedance matching characteristic and superior microwave attenuation characteristic of the absorber. The reflection properties of the material enhanced with variations in the wt.% of Fe-coated MWNTs and polymer. In this research paper, Fe-coated MWNTs are analyzed as promising microwave absorbing material and combined utilization of dielectric loss and magnetic loss absorbent design shows great design flexibility and diversity in the frequency range 8÷13 GHz.

3

Nadprzewodnictwo międzyziarnowe wysokotemperaturowych nadprzewodników badane techniką absorpcji mikrofal

Niewolski J., Kołodziejczyk A., Zając T.

Przegląd Elektrotechniczny

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2003

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R. 79, nr 9(2)

612-615

PL

Zmierzono bezpośrednią i modulowaną magnetycznie absorpcję mikrofalową w funkcji zewnętrznego pola magnetycznego dla nadprzewodników wysokotemperaturowych z rodzin itrowej, bizmutowej i talowej. Badania przeprowadzono dla mikrofalowego pasma X w temperaturach 4,2 K, 66 K i 77 K. Zaobserwowano korelację między wartością niskopolowego maksimum absorpcji mikrofal a międzyziarnowym prądem krytycznym Josephsona. Wyniki pomiarów porównano z teoretycznymi modelami mikrofalowej absorpcji otrzymując dobrą zgodność.

EN

Magnetic field dependences of the direct and the magnetically modulated microwave absorption versus external magnetic field of a numbers of Y-, Bi- and Tl-based high-temperature superconductors were measured at 4.2 K, 66 K and 77 K by X-band microwave spectrometer. Correlation between value of the low field maximum of the absorption and the inter-grain critical currents of Josephson junctions was found. Results were analyzed and compared to theoretical models of microwave absorption available in the literature yielding good agreement.