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The paper proposes a systemic transition from the location and orientation of tolerance product features to linear and angular coordinates in the coordinate system of the product electronic model. The coordinate system is formed by designing datums set with a total informativeness content of six constrains on the object degrees of freedom, three of them being linear and three of them being angular constrains. The main design datums determine the object position in the product and form a generalized coordinate system. Auxiliary design datums determine the position of the attached object on the considered object and form an auxiliary coordinate system. Each element of the product has a certain informativeness content to limit the degrees of freedom, both linear and angular. When forming a Cartesian coordinate system, the datum element transfers piece or all of its informativeness content to it. As a result, the coordinate planes acquire different informativeness of three, two and one, and the coordinate axes acquire that of four, two and zero. The coordinate axes and planes informativeness content determines the number of linear and angular coordinates that can be set relative to them. Similarly, the feature datums informativeness means the number of linear and angular coordinates that must be specified in the coordinate system for its single-task location and orientation. The transition to a coordinate system for standardizing location and orientation deviations demonstrates compliance with a systematic approach that improves the quality of products in terms of the geometric specifications accuracy.

This study is devoted to the recent problem of quality assurance of technical products in the design process. However, it is impossible to solve this problem by using international standards ISO and geometrical product specifications developed by ISO technical Committee ISO/TC 213. They lack a reference system of geometrical characteristics, i.e. the coordinate systems of the products are not applied. On the other hand, the technical committee ISO/TC 184 – "Industrial automation systems and integration" introduced in their standards coordinate systems for the design of machine tools with numerical control, which made parts of products, 40 years ago, since neither design nor manufacture, nor the development of control programs or the control of parts after processing can be without coordinate systems. At the beginning of the XXI century, the same technical committee developed a series of international standards for the implementation of electronic geometrical 3D models of products, in the structure of which coordinate systems were introduced. Consequently, the coordinate system of products should be introduced in the standards for geometrical specifications ISO-GPS. With that study purpose, a new matrix of common GPS standards of a higher level on a coordinate basis was recommended.

The paper considers the types of heat transfer in the furnace chamber and ash residue values influence on the heat released and received in the furnace. The influence of different grades of coal (Kamyshanskij, Taldinskij and Ekibastuzkij deposits) with ash residue value from 16.4 to 43 % on the furnace combustion heat was analyzed. The ash residue value influence on the value of the heat received in the combustion chamber, which is the boiler efficiency defining characteristic, is considered. The graphical dependence of the heat amount received in the combustion chamber on the ash residue for the different types of solid fuel is shown.

The method for the experimental study of the viscoelastic properties of pneumatic elements with a rubber-cord casing is proposed. Based tests of relaxation in which the height of the pneumatic element is kept constant (a practically incompressible fluid is used as the working medium). The implementation of the method is illustrated by the example of the rubber-cord casing of the balloon type of model N-50. The value of the absorption coefficient (relative hysteresis) is established, which in order of magnitude coincides with the value of the absorption coefficient of tread rubbers given in literary sources. In the process of holding the height of the pneumatic element at a constant level, increments of the force of the pneumatic element and overpressure are proportional to each other with a proportionality coefficient depending on the value of the internal volume and height of the air element. The comparative analysis of the features of the operation of pneumatic elements in cases where the working medium is a gas or liquid is done. The results obtained are of interest in the development of vibration protection and vibration isolation systems for technical objects, the design of which includes air springs, air damping shock absorbers and rubber-hydraulic vibration mounts.

A method for the experimental construction of isobaric static (equilibrium) power characteristics of pneumatic elements with a rubber-cord casing at a constant temperature is proposed. This method also allows you to determine isobar geometric characteristics, establishing a relationship between the height of the pneumatic element and the increment of its internal volume relative to some fixed position. The practical implementation of the method is illustrated by the example of a pneumatic element with a rubber-cord casing of the balloon type of the model N-50. The agreement of the experiment with the theoretical data calculated by the traditional method, widely used in the scientific literature, is analyzed. The obtained parameters are mandatory for the model of air spring and study the damping phenomenon. The results of the study are intended to develop vibration protection and vibration isolation systems for technical objects, the design of which includes air springs and air damping shock absorbers.

The international organization for Standardization has developed a series of standards for the implementation of electronic geometrical models of products, where coordinate systems have been introduced for the first time. However, it is not considered in the electron models that the different functional purposes of both the coordinate planes and axis are differed. In order to improve the quality of project documentation developed with the help of electronic models, the geometric specifications of coordinate systems were determined, coordinate planes and axes were established to perform six basic 2D projections of the product. A new geometrical specification "informativeness" is introduced as the number of product degrees of freedom restricted by the base, coordinate plane or axis. The coordinate system of the product is materializes by a set of its design datums with a total informativeness of 6. Coordinate planes of the rectangular coordinate systems have the informativeness of 3,2 and 1, the coordinate axes -4,2 and θ (zero).

The paper presents the results of experimental studies of an arcjet thruster in pulsed mode of operation on nitrogen with a thrust value of up to 32 mN and energy consumption of up to 30 watts. The pulse mode of operation of the arcjet thruster is provided by the developed power source. At measured values of temperature at the nozzle and pressure in the arc chamber of the engine in a pulsed mode of operation define the basic characteristics of gas-dynamic functions of gas flow. The forecast of the achieved values of the specific impulse when using ammonia as a working fluid is carried out

The article is devoted to the topical problem of the reliability of measurements of geometrical specifications of technical products. The purpose of this article is to improve the quality control of the linear dimensions of the parts by the two-point measurement method. The goal of the article is the study of advanced methodical uncertainties of measurement of linear dimensions of plane-parallel prismatic elements. The method of research is geometric modeling of deviations of the element surfaces form and position in the rectangular coordinate system. The research was carried out for various executive elements with regard to their information content corresponding to the classes of kinematic pairs in the theory of mechanics and the number of constrained degrees of freedom in function of the basic elements. Prismatic elements with informative content 3, 2, 1 and θ (zero) were studied. Uncertainty assessment of two-point measurements were made by comparing the measurements results of linear dimensions and functional dimensions of the element maximum and minimum material constrained by the limits of maximum and minimum. As a result of studies of the two-point measurements accuracy, it is found that the methodical uncertainty is formed when measuring the average size of elements for all types of form deviations. The two-point measurement method cannot account for deviations of the location dimension of the element and therefore its use for items with less than the maximum informativeness creates unacceptably large methodical uncertainties of measurement the maximum, minimum and medium linear sizes. The same methodical uncertainties occur under the arbitration control of the parts linear dimensions by the limit two-point gauges.

The study is carried out on the urgent topic for technical products quality providing in the tolerancing process of the component parts. The aim of the paper is to develop alternatives for improving the system linear sizes tolerances and dimensional fits in the international standard ISO 286-1. The tasks of the work are, firstly, to classify as linear sizes the elements additionally linear coordinating sizes that determine the detail elements location and, secondly, to justify the basic deviation of the tolerance interval for the element's linear size. The geometrical modeling method of real details elements, the analytical and experimental methods are used in the research. It is shown that the linear coordinates are the dimensional basis of the elements linear sizes. To standardize the accuracy of linear coordinating sizes in all accuracy classes, it is sufficient to select in the standardized tolerance system only one tolerance interval with symmetrical deviations: Js for internal dimensional elements (holes) and js for external elements (shafts). The main deviation of this coordinating tolerance is the average zero deviation, which coincides with the nominal value of the coordinating size. Other intervals of the tolerance system are remained for normalizing the accuracy of the elements linear sizes with a fundamental change in the basic deviation of all tolerance intervals is the maximum deviation corresponding to the limit of the element material: EI is the lower tolerance for the of the internal elements (holes) sizes and es is the upper tolerance deviation for the outer elements (shafts) sizes. It is the sizes of the material maximum that are involved in the of the dimensional elements mating of the shafts and holes and determine the fits type.

To determine the plasma arc parameters of an arcjet thruster, the kinetic theory of gases is used. We can find a well-known statement about the adiabatic character of the compression process due to the growth of the gas temperature in a change in its spectral composition and in the Doppler effect. The use of tungsten in the nozzle design details explains the appearance of atoms of this element in the plasma volume. The emission spectra of tungsten allow us to indirectly judge the temperature of the arc discharge and its character. Absorption of the long-wavelength wing of the line contour at λ = 465.987 nm substantiates our conclusion about the consumption of the anode material in the process of operating the arcjet. The Doppler shift of the emission lines of argon allows us to determine the rate of the gas jet escape. The results of the study can be useful in the design of aircraft.