MECHANICAL ENGINEERING АND ENGINEERING SCIENCE
The paper presents results of the investigations pertaining to morphology and chemical composition of thin surface layer of structural carbon and corrosion-resistant steel after the process of electro-impulse polishing. It has been established that removal of metal being polished occurs due to anode processes on the treated surface that leads to formation of surface films that can have different nature and thicknesses. The paper reveals that under conditions of electro-impulse polishing anodic dissolution of steel takes place with direct participation of anions of electrolyte solution.
In order to obtain an adequate mathematical model of vehicle hydro-mechanical steering which is equipped with a steering mechanism combined with power steering and a rotary distributor it is initially necessary to get current consumption values in the units of hydraulic scheme which are determined by dynamic changes of flow passages of pressure and drain circuits according to turning angle of the distributor. Such characteristics are usually determined experimentally.
The paper proposes a sequence which is recommended for determination of consumption characteristics which is formed with due account of multi-directional kinematic perturbations, mechanical clearance, possible emergence of hydraulic backlash and desired throttling law.
The factors account makes it possible to obtain an acceptable mathematical analogue of a hydro-mechanical steering for execution of robust investigations.
The paper considers a problem pertaining to selection friction pair materials for plain bearings of mining equipment which are lubricated with nano-dispersed magnetic oil. Methodology for equipment tests, technology for obtaining new anti-friction materials (polymer, ceramic, amorphous) and investigation results are presented in the paper.
NANOTECHNOLOGY AND NANOMATERIALS
This paper presents results that reveal influence of modifiers characterized by different nature and composition and subjected to heat treatment on operational characteristics of single and binary compositions. Interaction between dispersed clay particles and dependence of coating properties on their mass content in oligomeric and polymeric matrices have been justified in the paper. The paper contains data that prove an increase of coating hardness by 15–20 %. The coating composition includes thermally-treated dispersed clay particles.
A technology has been developed to obtain porous powder materials on the basis of spherecal powder particles of 12Х18Н10T сorrosion-resistant steel by technological coating deposition on them –condensate from layered and composite Si and (Si + C) or Si and (Mo + Si) nano-layers. Their deformation at points of spherical particles contact creates press forming conditions with sufficient strength rate at pressure below yield point of steel powder (below 200 MPa). The subsequent sintering occurring with an exothermic reaction in the coating ensures particle sintering in their local heating within 1100–1200 °С temperature range.
PROCESSES AND MACHINERY OF AGRICULTURAL ENGINEERING SYSTEMS
It has been established that existing mineral fertilizer spreaders do not fully meet technical requirements. In order to ensure continuous and reliable fertilizer dosing it is necessary to destruct bridges above exhaust ports and facilitate forced fertilizer feed to the spreader.
The results of theoretical investigations on conical-helical agitator-bridge breaking cone of mineral fertilizers have made it possible to establish interdependence of the motion path of an elementary volume of mineral fertilizers along helical spiral coil of the agitator and its relative speed on functional and technological parameters such as cone-generating angle to its axis, an angle of lead, a radius of helical surface, coefficients of external and internal friction and an angular velocity. Modifying the above-mentioned parameters it is possible to select the optimum combinations depending on the accepted criteria for efficient turning.
The paper considers a process of interaction between a wheel tractor with a mounted implement while crossing relief irregularities. An analytical model has been developed that demonstrates small linear and angular interactions of the tractor and the mounted implement in the longitudinal vertical plane. The paper contains justified proposals on the relative position of tractor and implement centers in order to ensure longitudinal stability of the unit as a whole. Recommendations have been given for setting length of an upper arm and creation a regulatory system.
CIVIL ENGINEERING AND ARCHITECTURE
The paper presents investigation results pertaining to peculiar features of thermal insulation material production and description of their property study. The production process presupposes swelling of alkaline-silicate raw materials at temperature 300–500 °C of mixes, are presented.
The paper shows a principal possibility to develop a technology for production of qualitative regenerated mixtures from old asphalt concrete pavement on the basis of electro-hydraulic cold method applied for their recycling.
TRANSPORT
The paper presents the developed principle for volumetric division of operating fluid flow in multi-motor hydraulic drive of working elements of construction and road machinery. Basic technical solutions and design parameters of discrete rotary-type hydraulic distributive valve have been determined in the paper.
CHEMICAL TECHNOLOGY
Process of alkaline pulping in the presence of salts of some metals having mixed valence has been simulated on the basis of the executed investigations. The paper reveals that optimization of alkaline (sulphate) pulping depends on chemical nature and metal and its amount which is introduced in the form of salt.
ECONOMICS AND MANAGEMENT OF NATIONAL ECONOMY BY BRANCHES AND FIELDS OF ACTIVITIES
The paper presents an economic model for operation of the national cargo service which is responsible for international freight transportation as a general totality of infrastructure subsystems, customer services and international cargo transportation services granted by national transport operators.
ISSN 2414-0392 (Online)