Systematic analysis of quantitative structure – property relationships for dyes of different nature has been reviewed. On the basis of the experimental results published in the literature and theoretical evaluation of amphiphilic and electrophilic properties of dyes of different nature several basic conclusions of scientific and practical importance are proposed. It was found that water/octanol partition coefficients exhibit correlation with dye partition between hydrophobic synthetic fibres and dyebath as well as dye affinity. Hydrophobicity of dyes controls several technical properties of dyes and dyeings, such as wash fastness and light fastness, migration factor, rate of dyeing and fixation rate. Energy of frontier electronic orbitals (HOMO and LUMO energies) correlates with different properties characterizing redox properties of dyes: oxidative and reductive destruction in chemical reactions, photochemical and biochemical destruction of dyes, wash and light fastness of dyeings. The results of this study are useful for physico-chemical analysis of dye sorption by textile fibres, destruction of dyes in polymers and solutions as well as for design of new dyes of high quality.

The article presents a methodology for determining the parameters of the spatial trajectory of movement of a standard cutting tool processing ring gears with spatially modified teeth working by the copying technique. The implementation of the methodology makes it possible to determine the reference points coordinates of the trajectory of movement of the cutting tool in the process of multiple-axis processing of spatially modified teeth of spur wheels on CNC machines. The results obtained in the development of the methodology for determining the trajectory of the cutting tool movement can be further used in the process of performing the technological preparation for the production of spatially modified ring gears, including large-scale ones, in the conditions of single and small-scale production, as well as with choosing a technological equipment, the appointment of cutting modes, as well as in the process of writing control programs for CNC machines.

No abstract

If the positive ions are placed in an intense electric field, they will be attracted and accelerated to the negatively charged piece. This phenomenon is currently used as part of an ion deposition process. One can consider that the deposition process is the result of the accelerated ions' impact with the workpiece surface layer. In the specialty literature, the ion deposition process is included in the so-called larger category of the physical vapour deposition. This paper presents some considerations of the authors concerning the base phenomena and applied aspects of the ion deposition process. To improve some service properties (corrosion and wear resistance, friction coefficient etc.) of certain pieces or tools, thin layers of titanium nitride can be deposited on their surfaces. The titanium nitride deposition process can be regarded as a system; as input parameters, one may consider the type of the material to be deposited and of the substrate, the type of the gas existing or obtained in the vessel, the electrical parameters used to generate the ions and to accelerate them to the cathode, the pressure in the recipient etc. The paper includes some hypotheses developed by the authors regarding the phenomena occurring during the plasma deposition process of titanium nitride. There are also some considerations concerning the changing of the surface roughness as consequence of the plasma deposition process.

The use of cutting fluids in turning can change thermomechanical loading of cutting tools. Currently, manufacturers provide a wide range of cutting fluids, which have different combinations of lubricating and cooling properties. Depending on cutting conditions, this combination can reduce tool wear in different degrees, and, in some cases, to even increase it. Therefore, an effective choice of cutting fluids requires a considerable amount of experiments, which requires cost and time. To solve this problem in the software SIMULIA/Abaqus Explicit 6.10 was developed thermomechanical model of the turning process by cutting tools with PVD-coating, which allows simulating the effect of any combination of cooling and lubricating action. An Arbitrary Lagrangian-Eulerian formulation method was used in the modeling. Under the lubricating and cooling action is understood the final result of interaction of cutting fluids with the cutting zone. Modeling of lubricating action of cutting fluid is performed by introducing into the model corresponding average coefficient of friction in the contact zone of cutting tool, worked material and cutting fluid. Modeling of cooling action of cutting fluids is implemented through the introduction of the heat transfer coefficient, calculated on the basis of cutting conditions and thermo-physical properties of cutting fluids. As an example, turning of austenitic stainless steel X10CrNiTi18 by carbide cutting insert with TiN-coating for a predetermined cutting condition was examined. A selection of cutting fluids of the proposed range, formulations of which have different combinations of cooling and lubricating properties ("Unizor-M", "Ferrobetol-M", "EkoEM-1", "STARCUT E9", "SAFECUT M120") was accomplished through the simulation model and the calculated data contact stresses. Experimental studies have confirmed the validity of this choice by comparing the rate of flank tool wear in the using different cutting fluids. The rate of wear was determined by surface micrographs of flank tool. An application of the recommended cutting fluid "SAFECUT M120" has reduced wear by 4 times as compared with the application of the "Ferrobetol-M", the use of which has shown the highest wear. The model developed can be used for selecting a predetermined range of cutting fluids, in determining the optimal combination of lubricating and cooling actions for establishing the required characteristics of cutting fluid or in developing new formulations of cutting fluids.