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The present article considers a comparative analysis of two elastomers, polyurethane (PUC) and organosilicon (OSC), both modified with 1.0-9.0 wt% multiwall carbon nanotubes (MWCNTs). The MWCNTs-1 and MWCNTs-2 were synthesized through CVD method using Co-Mo/[Al.sub.2][O.sub.3]-MgO and Fe-[Co/.sub.2,1][Al.sub.2][O.sub.3]. The results obtained showed that the lowest bulk conductivity (5 * [10.sup.-10] S * [cm.sup.-1]) was typical for PUC elastomer modified with 1 wt.% MWCNTs-2. As for OSC elastomer (modified with 9 wt.% MWCNTs-1), the lowest bulk conductivity was found to be 0.4 S * [cm.sup.-1]. The maximum temperature field uniformity was established for OSC elastomer modified with 7 wt.% MWCNTs-2, whereas in the modified PUC-based elastomer, the nonuniform temperature field took place. This might be caused by local MWCNTs entanglement manifested in the formation of agglomerates or a denser packing of conductive networks. The best combination of the polymer matrix and MWCNTs type was revealed. Finally, it was established that for electric heaters, it is the most efficient to employ OSC modified with 7 wt.% MWCNTs and use MWCNTs-1 or MWCNTs-2, depending on the feeding voltage level of 12 or 24 V. This study is of special importance in household purposes, clothing with built-in heating panels, car/tractor systems, minibus interiors, onboard thermal ventilation systems, clothing, and aircraft industries. KEYWORDS catalysts, MWCNTs-based heating composites, MWCNTs synthesis, organosilicon and polyurethane compounds, percolation, | INTRODUCTION The advanced electrical conductors based on nano-carbon or their metals nanocomposites are superior to copper and aluminum from the conductivity point of view. The use of these advanced [...]

The article presents the synthesis of multi-walled carbon nanotubes (MWCNTs) on the porous nickel foam (3D-Ni) surface using the chemical vapor deposition (CVD) method, followed by the field emission characteristics of the resulting 3D-Ni/MWCNT nanocomposite structures. The characterization of the 3D-Ni/MWCNT morphology showed a uniform distribution of the "moss-like" CNT coating on the walls of the porous 3D-Ni. TEM images showed a high number of walls in MWCNTs, which made such a material resistant to destruction under conditions of strong electric fields during the field emission process. The studies also showed a high degree of chemical purity of the synthesized MWCNTs under the presented technological conditions. An increase in the emission current due to the introduction of CNTs into the structure of porous 3D-Ni is shown. 3D-Ni/MWCNTs field emitter showed a low turn-on field of 5.41 V/μm; a field enhancement factor of 915; and high operating stability. For the first time, the current mode of 3D-Ni-MWCNTs cathode was tested for compliance with the classical field emission law using the Forbes "orthodoxy" test. [ABSTRACT FROM AUTHOR]

Researchers worldwide are studying thermal energy storage with phase change materials because of their substantial benefits in the enhancement of energy efficiency of thermal drying systems. A two-stage convectivevacuum impulsive drying plant is a technology for the manufacturing of chemical and food products with high quality and low energy costs. Energy consumption during the drying process is the main indicator in terms of economy. In this paper, a brief and focused review of the peculiarities of TEAs with PPCMs and opportunities of their application in such drying systems is done and discussed. The paper described the mentioned manufacturing system. The advantages of paraffin wax and thermal conductivity improvement techniques were demonstrated for their use as heat storage materials in CVID drying units. The results of similar previous studies were presented. The results of the experimental studies conducted by the researchers proved that the use of heat accumulators with PCMs increased the overall energy efficiency of drying systems. Finally, integration of TEAs based on modified PPCMs in the CVID system was recommended to intensify thermal energy, reduce thermal influence on the main indicators of the vacuum pump during the evacuation process, and decrease production costs. [ABSTRACT FROM AUTHOR]