Volume 4 Issue 1
Authors: Marina N. Dubyago; Nikolay K. Poluyanovich
Abstract: The paper is deal with detection and estimation of level of the partial discharges (PD) in insulating materials of technical systems. Theoretical consideration of processes and mechanisms of electric breakdown in insulating materials is fulfilled. Comparison of characteristics of PD is executed at different types of electric breakdown allowing to allocate and identify different types of defects and by that to establish characteristics of a working condition of high-voltage insulating materials. Practical application of a technique of diagnosing of technical condition, insulating materials under operating conditions and identifications of malfunctions of the cable systems (CS) on the basis of the PD method is represented.
Keywords: Insulating Materials; Cable System; PD Method
Authors: Victor K. Pustovalov
Abstract: The investigations and the use of nanoparticles (NPs), as photothermal agents in light-to-heat conversion processes in nanoenergy and nanotechnology are fast growing areas of research and applications. Analytical investigation of the light-to-heat conversion by nanoparticle ensemble under radiation action was conducted. The investigation of the influence of NPs parameters (their radii, absorption efficiency factor, density and heat capacity of NP material, concentration), the characteristics of radiation (wavelength, pulse duration, radiation beam radius), the surrounding material (its density, heat capacity, and heat conduction coefficient, characteristic length of radiation extinction) on the efficiency of the light-to-heat conversion is carried out. The possibility of thermal confinement (saving NP and material thermal energy practically without heat exchange with surrounding) has been established for single NP and irradiated volume of medium with NPs for determined time intervals. These results can be used for the description of the light-to-heat conversion processes in experimental investigations in nanoenergy and nanotechnology.
Keywords: Light-to-Heat Conversion; Nanoparticles; Ensemble; Thermal Confinement; Analytical Investigation
Authors: Kai Wang; Huan Qi; Xudong Sui; Guojian Li; Qiang Wang; Xiangkui Zhou
Abstract: Titanium Aluminum Silicon Nitride (TiAlSiN) coating has been expected to be applied in the field of cutting new difficult-to-machine materials such as titanium and superalloys. TiAlSiN coatings in the range of 4-8 at.% silicon content are prepared by reactive magnetron sputtering. The results show that the structure of nanocrystal surrounded by amorphous Si3N4 was formed in all the TiAlSiN coatings. When the silicon content increases to 8 at.%, the grain size of TiAlSiN coatings is refined to 7 nm and distributes in a narrow size range. Meanwhile, the nano-column growth of the TiAlSiN coating with 4 at.% silicon disappeared and changed to nanocrystals growth. The hardness as a function of the silicon content showed a nonlinear relationship, and the highest hardness is obtained at 6 at.% silicon content. TiAlSiN coating with 4 at.% silicon content has the highest critical load of 87.8 N. With increasing silicon content, the preferred orientations change from (111) to (200) and the adhesion strength decreased. The optimized mechanical properties of the TiAlSiN coatings, with a hardness of about 32.8 GPa and a critical load of 69.2 N, will have a promising application in modern cutting technology.
Keywords: Sputtering; TiAlSiN Coatings; Microstructure; Nanocomposite; Nanoindentation; Adhesion