CALCIUM IN SOIL HUMUS OF WEST-SIBERIAN TRANSECT

The paper analyzes the behavior of one of the main components of humus (humic acids - calcium system) depending on the participation of calcium in the biological cycle of substances. The role of calcium in the formation of ecological stability of humic systems is shown, which largely determines the environmentally sustainable agriculture. It is shown that the changeable calcium amounts to no more than a half of its total content in humus horizon of automorphic zonal soils. Within the limits of the transect, the participation of calcium in binding of humic and fulvic acids is distributed according to their content in humus composition. Additional assessment of exchangeable calcium content to be determined by nontraditional method showed the same geographic regularity of its distribution in the soils of the transect as in the case of distribution of the main characteristics of humus.

NONTRADITIONAL METHOD OF CHEMICAL MODIFICATION OF THE SURFACE OF POROUS SILICA

The main results obtained in the study of the possibility of low-temperature chemical modification of porous silica, applying various nanodispersed substances to their surface are given. It has been shown that the use of the chemical transport reaction (CTR) $ \mathrm{H_{2}O_{2}/ZnO} $ for this purpose with the participation of $ \mathrm{H_{2}O_{2}} $ vapors at room temperature makes it possible to apply a number of oxides, sulfides and metal halides to the surface of various sorbents. An important advantage of the proposed modification method is that changes in the original texture parameters of the substrate are minimized. Using the example of modifying the behavior of highly pure $ \mathrm{SiO_{2}} $ with zinc oxide, it was shown that the decomposition of gaseous intermediate products of CTR $ \mathrm{H_{2}O_{2}/ZnO} $ occurs mainly in pores with a diameter of more than $ 6~nm $.

Influence of shrinkage of polymer on the stationarity of propagation of frontal polymerization heat waves

The purpose of this work was to study the causes of the formation of nonlinear and spin modes in the process of frontal polymerization (FP). The latter is an autowave process of the propagation of polymerization heat waves, and is a nontraditional method for the synthesis of various polymers and polymeric composites. Monomers of metal-complexes of acrylamide with and without additions of inert and nano-fillers were chosen as objects of study. Research data on dilatometric analysis, as well as on kinetics and macrokinetics of the polymerization processes of the monomers in frontal mode are presented. On the basis of the results obtained, a conclusion was drawn on the stability loss and transition boundary from a stationary mode to nonstationary one during FP. It was shown that, during the polymerization processes, shrinkage of the resulting polymer composites occurs, commensurate with the phase of the heat wave oscillations, which disturbs the propagating heat waves from layer to layer and violates the stationarity of the process. This, in turn, results in the formation of spin-like rings and a nonstationary mode of FP.

Parametric Optimization of WEDM Characteristics on Inconel 825 using Desirability Research

The present research focuses on the optimization of wire-cut electric discharge machining (WEDM) parameters. In this study, RSM based multi-response desirability method is used to optimize the WEDM characteristics for single and multiple responses. Input parameters of WEDM viz. pulse-on time, pulseoff time, spark gap voltage, wire tension, peak current, wire feed and performance was measured in terms of material removal rate (MRR) and surface roughness (SR). WEDM is a nontraditional method uses the spark erosion principle to produce the intricate shape and profiles of difficult-to-cut material. Inconel 825 is increasing in demand in the aerospace industry for more heat resistant and tough material. Because of its robust nature, it is difficult to be machined with conventional methods. WEDM is best alternate to overcome this problem. It has been observed that at Ton 111 MU, Toff 35 MU, SV 46V, IP 140A, WT 9 MU and WF 6 m/min, the values obtained for MRR and SR are 32.015mm2/min and 2.528 μm respectively

Investigation on the Surface Finish, MRR and the Surface Damage during the EDM of Tungsten Carbide

EDM is a nontraditional method of removing material by a series of rapidly recurring electric discharges between an electrode (the cutting tool) and the workpiece, in a medium of a dielectric fluid. EDM is a precision machining technique and is used in making dies and molds of extremely hard materials that cannot be machined by conventional techniques. The present work was conducted in order to investigate the surface finish, material removal rate and the surface damage during EDM. Copper and carbide were taken as the electrode and the work materials for the present study. The influence of current and pulse-on time on the responses were studied. Design of Experiment (DOE) was used to conduct the investigation. It was found that MRR and surface roughness increases with both current and pulse on time. Tool wear, work surface damage and materials migration between the electrode and the workpiece was found to be increased with current.