This paper presents the results of an experimental study on the operation of a wick-type heat pipe equipped with an innovative induction heating system. This work is a logical continuation of theoretical studies published by the authors in 2025 and aims to verify a mathematical model of thermal processes in the “inductor–magnetic core–heat transfer fluid” system. The design of the tube under study includes a copper housing, a wick based on an AISI 304 stainless steel mesh, and a ferromagnetic core made of AISI 430 steel. Heating was performed using a parallel resonant circuit at a frequency of 28.15 kHz. The aim of the study was to determine the effect of the tilt angle on the thermal efficiency of the tube in the low-temperature range (18–50°C). The architecture of the experimental setup is described, which includes a two-channel thermometer based on an Arduino microcontroller and film thermistors, which ensure high measurement accuracy in the evaporation and condensation zones. A series of experiments yielded sets of temperature curves for tilt angles of 30°, 45°, 60°, and 90°. It was found that in the vertical orientation (90°), the tube exhibits the highest isothermality and the shortest time to reach steady state. A characteristic temperature threshold for phase transition activation was identified in the range of 30–32°C. It has been proven that when the tilt angle is reduced below 30°, thermal efficiency decreases significantly, which is due to the limited capillary potential of the AISI 304 steel wick, which does not ensure sufficient condensate return to the heating zone under conditions of weak gravitational influence. The obtained data allow for the optimization of heat pipe parameters for their application in mobile personal heating systems, particularly in thermal mats, and indicate the need to modernize the wick structure for operation in a horizontal position.
Систему Zr–Ru–Al досліджено за 900 °С методами Х-променевої дифракції та скануючої електронної мікроскопї. Встановлено низку фазових рівноваг в цій системі за вмісту Al ≤ 55 ат. %. Підтверджено існування двох тернарних сполук: ZrRuxAl2-x з гексагональною структурою типу MgZn2 (просторова група (ПГ) P63/mmc): a = 5,2225(5), c = 8.1980(8) Å та кубічної Zr6Ru7+xAl16-x (x=0.58) структурного типу Th6Mn23: a = 12,27655(8) Å. Вздовж ізоконцентрати за 50 ат. % Ru виявлено неперервний твердий розчин на основі бінарних сполук RuAl та ZrRu зі структурою типу CsCl (ПГ Pm3^(-)m).
In this work, polymer nanocomposites films of (PEO-MnO2-SrTiO3) were manufactured using the casting method, where varying percentages of nanoparticles (MnO2-SrTiO3) were mixed at concentrations of 1.7%, 3.4%, and 5.1%, respectively. The morphological and optical properties of (PEO-MnO2-SrTiO3) films were studied. The results showed that by increasing the percentages of MnO2-SrTiO3 the optical properties improved. The results showed that with increasing concentration, the morphology on the surface of PEO-MnO2-SrTiO3 appears homogeneous and more cohesive. The absorption of PEO doped with MnO2-SrTiO3 increased of 75% with wavelength equal to 380 nanometer and 76% with wavelength equal to 680 nanometer, by increasing the content of MnO2-SrTiO3 nanoparticles to reach of 5.1%. The transmittance decreased from 43% to 41%. Absorption coefficient increased from 6453 cm-1 at Eph=4.41 electron volt to reach 8589 cm-1 for MnO2-SrTiO3 nanoparticles content equal to 5.1%. The energy gap for the allowed indirect transitions decreased from 3.7 eV to reach 3.3 eV while content of the nanoparticles increased to reach of 5.%. The energy gap of forbidden indirect transition decreased from 3.7 eV to 3.2 eV while the nanoparticles content of MnO2-SrTiO3 increased to reach of 5.1%. Extinction and refractive indexes, and dielectric constant increased. The optical conductivity increased from 3.1 × 1012 S-1 at the wavelength of 800 nanometer for pure PEO to 1.6 × 1013 S-1 when the addition of nanoparticles equal to 5.1%. Results showed that the PEO-MnO2-SrTiO3 films could be used for transistors application and flexible solar cells, and diodes.
The influence of structural defects in fast neutron-irradiated CdSb to 2 ⸱ 1018 n/cm2 on the state of the crystal surface was studied. It was shown that during storage of irradiated crystals, their surface (layer 60 ÷ 80 μm) increases its conductivity. A model is proposed that explains the influence of irradiation on the state of the crystal surface. The migration energy of interstitial cadmium atoms, the values of diffusion coefficients at different temperatures, and the frequency factor are experimentally determined. Also, the isochronal annealing of radiation defects in neutron-irradiated CdSb crystals was studied in detail.
In this study, glass systems with chemical composition (40-x)Li2O–10Y2O3–50SiO2:xV2O5 were prepared using melt-quenching method. The XRD patterns of the prepared samples conform to the glassy nature. Optical absorption spectra exhibit two absorption bands at around roughly 630 nm and 1030 nm, identified as the transitions due to 2B2→2B1 and 2B2→2E transitions of [VO]2+ ions. The intensities of these identified peaks are observed to grow with a slightly red shift with the V2O5 content in the glass matrix. The direct and indirect optical band gaps, evaluated using Davis-Mott theory, decreased with increasing V2O5 concentration, while the Urbach energy obtained from the Urbach rule increased. IR spectral analysis revealed that the glass samples exhibit various structural units via., asymmetric and symmetric stretching linkages, , linkages and ; it appeared that the intensity of asymmetric linkages was observed to increase by the expense of symmetric linkages with a gradual increase in the content of V2O5. The optical absorption spectra of the investigated glasses suggest the coexistence of V4+ and V5+ ionic species. The observed evolution of the characteristic vanadyl absorption bands with increasing V2O5 concentration indicates a possible shift in the V4+/V5+ equilibrium within the glass network.
