Papers by Keyword: Concentration

Abstract: The chrome alloy has better affinity with nitrogen atom in nitriding process than any other alloy elements in steel. The higher content of chrome element binds larger number of nitrogen atoms. However, the higher concentration of nitrogen atom on the surface of the steel does not often make thicker case depth. This study clarified the phenomenon. The nitriding process was performed in two stages, namely the boost stage in the fluidized bed with the composition of 80 % NH₃ and 20 % of N₂ in 4 hours at 550 °C. Subsequently, the diffusion process was carried out in fluidized bed with the gas composition of 100 % N₂ HP (high purity) in 2 hours. The chemical composition was measured by spectrometry and EDAX. The case depth was identified by micro-Vickers, and metallography was observed by SEM. The concentration of nitrogen atom on the surface of AISI 316 L is twice higher than that on the AISI 4140. The result shows that 0.1 to 1 wt % of nitrogen atom creates diffusion layer, 1 to 5 wt % of nitrogen atom produces nitride layer of γꞌ and ε, and nitrogen atom above 5 wt % forms white layer. The layer strongly depends on the percentage of nitrogen atom concentration. The nitrogen atom concentration is determined by the concentration of chromium element within the steel (AISI 316 L). Meanwhile, the depth of nitrogen atom diffusion is highly determined by the alloy element of Fe (AISI 4140).

Abstract: Among noble metal nanoparticles (MNPs), plasmonic effect of gold and silver nanoparticles (Au NPs and Ag NPs) is interesting to study due to their high near-field energy. This makes them excellent particles to absorb and scatter incident radiation in optical applications such as coupling them to fluorescent emitters to enhance their radiative decay and emission rate. This paper reviews and studies the methodology required for tuning the doping concentration and modelling plasmonic optical properties of Au NPs and Ag NPs by using finite difference time domain (FDTD) method. The frequency-dependent optical behaviour of MNPs is discussed. Plasmonic optical properties of MNPs can be characterised by their dimension, shape and doping concentration. Dimension and shape of MNPs can be simply defined in FDTD space grid (known as Yee grid). However, tuning MNPs doping concentration is more challenging which is undertaken by changing the spacing between MNPs and lateral boundaries of FDTD Yee grid. This can be vastly useful in Au NPs and Ag NPs optical optimization and applications to estimate plasmonic resonance based on doping concentration of particles.

Abstract: The integral-differential equation of the cascade process for ions was solved using the Laplace transform and the method of successive approximations, taking into account the energy loss during the formation of primary-knocked-on atoms (PKA) in a one-dimensional model of an elementary atom. It is shown that the solution includes a cascade-probability function (CPF) for these particles. The main properties of CPF are considered and its graphical dependencies on the depth of registration are presented. It is shown that with the specific ionization loss coefficient k = 0, the FQM turns into the simplest cascade-probability function. When λ₀→ 0, λ₀→∞ and n→∞, the KV-function is equal to 0. The sum of the probabilities for all possible collisions from 0 to ∞ is 1. As the detection depth h increases, for all values of n, the CRF increases, reaches a maximum and then decreases . With increasing n, the curves shift to the right.

Abstract: The article is devoted to the analysis of the composition and properties of the materials and liquids during transportation using pipeline and shows that in order to increase the efficiency of hydraulic transport systems in mining a transition to the transportation of slurries with a high concentration of solids in the slurry flow is necessary. Experimental studies have shown that slurry tailings of gold-containing ore with mass concentrations of more than 55 % are viscoplastic fluids. Experiments on a rotational viscometer allowed us to establish the main rheological characteristics of the studied slurries – shear stress and the dynamic effective viscosity. It has been established that over the entire range of concentrations from 55 to 65 %, the flow of slurries is described by the Bingham rheological equation. Experimental studies of hydraulic transport performed on a laboratory setup with a pipeline diameter of 50 mm confirmed the results obtained on a rotational viscometer. The curved of mixture stream is inclined straight lines that are cut off on the axis of the head in the sections, which determine the initial hydraulic slope corresponding to the yield shear stress on the rheological curves. According to the results of the experiments, a method has been developed for calculating the hydraulic transport of high concentrated slurries of tailings of gold-bearing ore. Calculations showed that in a given range the performance of the hydrotransport system and the mass concentration of the solid phase pressure losses vary from 11 to 84 m of water column/m. Head loss values increase with the increasing concentration. A sharp increase in the head loss occurs in the concentration range from 60 to 65 % and higher.

Abstract: Nano-SnO₂ is a relatively important semiconductor material. Its crystal structure is unique rutile type. It has the advantages of high conductivity, high transparency and stable chemical properties. It is widely used in gas sensing detectors and solar cells for photoelectric conversion. Applications. In this paper, SnO₂ nanofilms with different crystal structures were prepared by changing the three process parameters of salt concentration, reaction time and hydrothermal temperature in hydrothermal method. The samples were tested by scanning electron microscopy (SEM) and three-dimensional ultra-depth microscopy analyzer. As the concentration of the reaction solution increases, the macroscopic thickness of the film gradually thickens, and the three-dimensional structure of the surface changes from flat to coarse to coarse peak. The peak between the peaks first increases and then decreases, and the surface microstructure is The conditions change are not obvious. Through the comprehensive comparison of film integrity and surface area, it is found that the concentration is 0.03mol/L, which is relatively better.

Abstract: During the operation of thermal power plants, boilers, incinerators, vehicles, industrial enterprises for the production of synthetic fatty acids, building materials, paints, textiles, cardboard, paper, as well as resins and products based on them – plywood, chipboards, wood-fiber boards, plastics, etc. The environment is contaminated with formaldehyde. Formaldehyde acts climatically and toxically on local, regional and global processes in the environment and contributes to a high level of air pollution (air pollution index > 14) in almost all industrialized regions of Russia. Products containing formaldehyde, getting into residential and non-residential premises, create an environmental risk to public health. The article is devoted to determining the effect of formaldehyde on woody plants by biochemical and electrophysiological methods and developing a method of reducing the concentration of formaldehyde in the environment by introducing into industrial materials aluminosilicate sorbents of different crystal chemical structure, processed thermo-, in a pulsed magnetic field and under the combined effect of a pulsed magnetic field and temperature effects.

Abstract: Computer simulation of vacancy clusters distribution by depth in molybdenum irradiated by alpha particles within Cascade probability method has been carried out. Cascade probability functions have been calculated taking into account energy losses for alpha particles in molybdenum and depending on number of interactions and depth of particles penetration. Microhardness comparison of calculations and modified experimental data show their satisfactory fit.

Abstract: This work aims to evaluate the influence of the alkoxy precursor concentration on the morphological and electrochemical characteristics of the chemical conversion layer formed on a galvanized steel surface. Different films were obtained by the dip coating method varying precursor concentrations in 2, 5 and 10%. According to the SEM and EIS results the corrosion resistance property increases for higher GPTMS precursor concentrations.

Abstract: In this work, the calculation algorithms of cascade and probability functions and vacancy nanoclusters concentration were developed and their calculations for various incident particles in silicon and iron were made.

Abstract: Nowaday´s trend is the effort to replace metal materials with the polymers, which already have the irreplaceable place in the field of the construction of various applications. Development offices effort is to achieve the best polymer quality for which various ways of modification are used. Besides common fillers and e.g. modification using beta radiation, there is a possibility to modify these properties (creep resistance, hardness, tensile strength) with the nanofillers, which have also the irreplaceable place in the field of development. This article deals with the possibilities of use of the nanofillers in HDPE material and primarily with the influence on creep properties of thus modified matrix. The influence of nanofillers shows a considerable influence in various materials, which should contribute to better resistance during these long-term tests.