A Modeling Study for Moisture Diffusivities and Moisture Transfer Coefficients in Drying of “Violet de Galmi” Onion Drying

In the present work, the mass transfer characteristics, namely moisture diffusivity and moisture transfer coefficient of “Violet de Galmi” variety of onions were evaluated using the analytical model. Onions were dried in a single layer at different temperatures (40℃, 50℃, 60℃, and 70℃) and for a relative humidity of drying air of 20%. The results showed a reasonably good agreement between the values predicted by the correlation and the experimental observations. This model computed the Biot number, effective moisture diffusivity, and mass transfer coefficient. Effective diffusion coefficient values are obtained between 0.2578 × 10-9 m2·s-1 and 0.5460 × 10-9 m2·s-1. Mass transfer coefficients of “Violet de Galmi” onion drying vary between 3.37 × 10-7 m·s-1 and 13.38 × 10-7 m·s-1. Numbers of mass transfer Biot are found between 0.9797 and 2.9397. The activation energy Ea is 31.73 kJ·mol-1.

Physical Alloying of Plasma Metallization Carbide Nanocomposite Coating by Allotropic Carbon Nanostructures

The fundamental scientific problem for micro- and nano-electronics has been solved—methods for creating and investigating properties of physically doped materials with spatially inhomogeneous structure at the micro- and nano-meter scale have been developed. For the application of functional nanocomposite film coatings based on carbides of various transition metals structured by nanocarbon, for the first time in the world, we developed a new technique for their plasma deposition on a substrate without the use of reaction gases (hydrocarbons such as propane, acetylene, etc.). We have created nanostructured film materials, including those with increased strength and wear resistance, heterogeneous at the nanoscale, physically doped with nanostructures—quantum traps for free electrons. We learned how to simultaneously spray (in a plasma of a stationary magnetron discharge) carbides and graphite from a special mosaic target (carbide + carbon) made mechanically. As a result of such stationary sputtering of carbides and carbon, plasma nanostructured coatings were obtained from nanocarbides, metal nanocrystals and nanocarbon. Our design of such a target made it possible to intensively cool it in the magnetron body and spray its parts (carbide + carbon) simultaneously with a high power density of a constant plasma discharge—in the range of values from 40 W/cm2 to 125 W/cm2. Such sputtering with a change in the power or the initial relative surface areas of various parts of the mosaic target (carbon and carbide) made it possible to change the average density of carbide, metal and carbon in a nanostructured (nanocarbon and metal nanostructures) coating. The changed relative density of various components of the nanocomposite (nanostructures of carbide, metal, and carbon in the form of graphite) significantly affected the physical properties of the nanocomposite coating. The creating method of multiphase nanostructured composite coatings (based on carbides of transition metals) with high hardness of 30 GPa, a low coefficient of friction to dry 0.13 - 0.16, with high heat resistance up to 3000°C and thermal stability in the nanocrystalline state over 1200°C is developed. It is established that the presence of nanographite in the composite significantly improves the impact strength and extends the range of possible applications, compared with pure carbides. The solution to this problem will allow creating new nanostructured materials, investigating their various physical parameters with high accuracy, designing, manufacturing and operating devices with new technical and functional capabilities, including for the nuclear industry and rocket science.

Determation method for water content of diesel contaminated soil

With the increasing researches on geotechnical properties of the diesel contaminated soil( DCS),the water content measured is indispensable part during the early period. In this study,the relative error of water content measurement using the traditional method is as high as 20. 78%,which is no longer suitable for contaminated soil. Through a series of tests to measure the loss coefficient of diesel in the drying time,the authors finally proposed a modified calculation formula for test samples. The results show that the maximum relative error calculated by using the modified formula is 0. 96%,far lower than that of traditional formula,which can provide accurate data for further study of diesel contaminated soil.