The hydrocarbon group-type composition (so-called SARA-composition) is one of the main characteristics of oil, providing an information about its chemical nature and determining the quality of the obtained petroleum products. In world laboratory practice, data on the hydrocarbon group-type composition of petroleum feedstock are widely used to assess its colloidal stability and compatibility with crude oil, reactivity in various conversion processes, predicting physical properties, etc. Traditionally, the hydrocarbon group-type composition is determined in accordance with standard and research chromatographic methods that differ significantly from each other, which often leads to obtaining incomparable analytical results. In this paper, a comparative analysis of the results of determining the hydrocarbon group-type composition obtained in accordance with two test methods within the open-column liquid chromatography method is carried out for various of petroleum samples of Russian origin (commercial oils of different classes and two petroleum products). Using the standard test method ASTM D4124 (method B) and the research test method developed by JSC VNII NP, the content of identical hydrocarbon groups in the maltene part of petroleum samples was determined: saturated hydrocarbons (SH) and paraffinic-naphthenic hydrocarbons (PNH), naphthenic aromatic (NAH) and aromatic hydrocarbons (AH), polar aromatic hydrocarbons (PAH) and resins (R), respectively. It is shown that with an increase the density and viscosity of petroleum samples, the content of less polar groups (SH and PNH) in their composition decreases and the content of more polar groups (PAH and R) obviously increases, and there is no pronounced distribution pattern of the NAH and AH groups. Statistical processing revealed insignificant differences in the results for «heavy and viscous» oils, despite the large error of those obtained according to the research test method. Obtaining comparable results justifies the use of both test methods not only for the analysis of high-boiling petroleum products, but also for the analysis «heavy and viscous» oil samples.

To determine the content of macronutrients in rocks, soils and sediments, three methods of sample preparation were used by the X-ray fluorescence method: pressing powder samples; fusing in gold-platinum crucibles to obtain glass discs; fusing on graphite substrates followed by melting and tablet pressing. A detailed description of each of the methods used is provided. For fusion in gold-platinum crucibles, a ready-made LITHIUM BORATE FLUX (from the company CHEMPHYS) was used, its composition: Li₂B₄O₇ (67%) + LiBO₂ (33%) + alloying additive LiBr. For fusion on graphite substrates, powders of lithium tetraborate and metaborate in a ratio of 2:1, dried at 600°C. Random errors of the analysis are estimated: errors of sample preparation and intensity measurement. It is shown that in all cases, the total errors do not exceed the permissible level when conducting mass analyses of the III category. Standard samples of rocks, sediments and soils were used to obtain the grades, The metrological characteristics of X-ray fluorescence analysis techniques using each of the three sample preparation methods are presented. The residual standard deviations of the calibration dependencies are compared. The correctness of the analysis results was verified on three standard samples. The advantages and disadvantages of each sample preparation method are noted. The use of the simplest, cheapest and express method of pressing tablets from the source material is possible only if the content of elements in the analyzed samples does not exceed the limits of the calibration dependencies of this technique. The method of fusion in gold-platinum crucibles requires preliminary information about the chemical composition of the analyzed sample. The method of fusing on graphite substrates (followed by melting and pressing the tablet) is more versatile and has no restrictions on the composition of the fused sample. It is shown that the systematic errors of the method for pressed tablets exceed the errors of the methods using the second and third techniques. The work was performed on the AXIOS Advanced wave dispersive X-ray fluorescence spectrometer (PANalytical B.V., Holland).

A procedure for gas chromatographic determination of O-isobutylmethylphosphonate micro-quantities in industrial emissions with a concentration range from 0.5 to 50 mg/m³ has been developed. The target analyte was collected and concentrated using an aspirator of the required volume of the test medium taken from sources of industrial emissions through sampling tubes equipped with ready-made filter materials, two layers of filters of the PFC (Petryanova filter cloth) type, 12 mm in diameter, two layers of filters of the appropriate size, washed in ethyl alcohol and dried in air, made of dense cotton material «moleskin». Recovery of concentrated substances from the sample tubes was performed by extraction with isopropanol. Methylation with diazomethane was carried out to convert the desired substance to a volatile product for subsequent chromatography, by a method improved to obtain micro-quantities of dialkyl esters of MPA and its monoesters. The high efficiency of the proposed methylation method as a factor for obtaining solutions with a low content of impurities of both starting reagents and non-target reaction products has been experimentally proven, which leads to higher accuracy of microconcentration measurements. Trace impurities, including diazomethane residues, were removed by vacuuming the methylated solution for 2 – 5 min. The use of other methods to remove excess diazomethane does not give positive results: blowing diazomethane from the solution with an inert gas does not lead to noticeable changes even for 15 – 20 min, during which time part of the solvent is removed and, therefore, the concentration of the target product changes; the addition of additional chemicals, for example acetic acid, leads to contamination with two products at once-excess acetic acid and methyl acetate, in addition, the addition of excess competing reagent can lead to transalkylation with the participation of the target product and, as a result, to incomplete progress of the target reaction. Quantitative data were obtained by gas chromatography using a Varian CP-3800 gas chromatograph equipped with a pulsed flame photometric detector, the mixture was separated on a CP WAX CB capillary column. The methodology was tested at real control facilities, appropriately certified and implemented in environmental control and monitoring programs.

Temperature control of a medium bounded by walls without direct placement of sensors in it is important to ensure efficient operation of many devices and process units (heat treatment devices, engines, reactors, etc.). However, development of a monitoring method with a wide scope of application requires automation of determination of thermophysical properties of wall and medium materials without specialized tests, which is difficult due to the individual specifics of each object. The paper presents the results of determining the thermophysical properties of materials during indirect monitoring of the temperature of the medium bordering the wall. We investigated the difficulties arising in the automation of determining the properties of materials during adaptation of models of complex heat exchange between the medium and the wall with partially uncertain properties. We used simplified heat exchange models making it possible to present the model signals as increments relative to the initial moment for the time period and to reduce the effect of the mismatch between the functional form of the model and the object on the indirect monitoring results. The parameters unknown during model adaptation were determined based on retrospective data of a limited time domain. It is shown that the model can be used to monitor a generalized estimate of the temperature of the medium near the point of temperature monitoring in the wall with subsequent prediction of the consequences of varying the temperature of the isolated medium. The efficiency of the proposed approach is demonstrated using a case study of heating fireclay bricks. The results obtained can be used in developing universal temperature control methods applicable to various objects.

When studying mixtures of minerals, composites of complex composition, and selecting powder catalysts, problems often arise for which the small masses of samples used in thermogravimetry do not provide sample representativeness. This requires the use of other methods of analysis that allow the use of samples ten times larger in mass. The paper presents the results of a study of the thermolysis process of copper (II) sulfate pentahydrate using a thermovolumometric method. During the tests, a sealed container with the analyzed substance and a thermoelectric converter was placed in a tubular furnace. The gas released during thermolysis entered the bubbling tank through the capillary. SoundForge13 and TableCurve 2D programs were used to process experimental data. The sources of error in the thermovolumometric analysis technique are analyzed. Dependencies that can be used to improve its accuracy are given. It was revealed that the value of the repeatability index obtained as a result of assessing the repeatability of the method is 3 °C; in the range of densities of the evolved gases 1. 25 – 1. 43 kg/m³, the resolution of the method in terms of the mass of the substance is 12 – 13 μg. The results obtained can be used to determine the temperatures of phase transitions when studying processes occurring during heating of mineral compositions, as well as the temperatures of decomposition reactions of substances. The accuracy of measurements can be increased by careful sample preparation, reducing the heating rate of the sample and introducing corrections to the measurement result based on the obtained dependencies.

It is noted that reaction of bearing elements of structures and engineering components to service loadings, impacts of physical fields and corrosive environments is initiation not only fields of stresses and strains, but also fields of damages. At the same time depending on conditions of a loading and environment various mechanisms of accumulation of damages and fracture which indicators are essential changes in spectra of a response of technical systems to different impacts are realized. The analysis of parameters of a state of such systems by registration of spectral characteristics of service processes allows to carry out estimations of levels of their damage in rather full degree. On the basis of results of research of service states of technical systems on spectral diagnostic parameters approaches to the analysis of amplitude-frequency characteristicses of their actual states both in the regular allowed states, and upon transition to dangerous states owing to accumulation in them of dangerous service damages are offered. At the same time criteria of transition of technical systems from regular in emergency and catastrophic states at accumulation of critical limits of damage are formulated. Examples of the dispersed initiation of microcracks in material of structures parts at a cyclic deformation with their propagation in the main fractures, and also examples of the analysis of dynamic states on vibration spectra of a response of simple and compound technical systems with the crack which arose in them and with existence of defects are given. At the same time the possibility of obtaining initial computation and experimental information on parameters of a stress-strain state and damage of installation with use of methods of the spectral analysis of a response of a compound structure to vibration impact as a result of initiation of damage of its separate parts is shown. Results of such spectral analysis can be used for diagnostics and monitoring of conditions of regular service of high-loaded installations of a technosphere and transition of their states to limit emergency and catastrophic in relation to objects of power engineerings, space-rocket and aircraft equipment.

The paper reflects new experimental results describing the processes of deformation and fracture of composites with significant structural heterogeneity with concentrators. A large-scale approach to the development of the method of digital image correlation (DIC) under complex modes of external influences is proposed. A number of methods of fixation of recorded data under cyclic impacts are considered. The peculiarities of each of the presented ways of data fixation depending on the main purpose of the research on the basis of static and cyclic tests of carbon fiber reinforced plastic specimens are outlined. Recommendations on the use of «analog capture» and «flex capture» options of the program «vic snap» are presented. The recommendations are valid for solving problems related to the analysis of regularities of deformation and fracture of objects with structural heterogeneity made of polymer composite materials under different modes of external loading. The study reflects the main methodological peculiarities arising when working with the non-contact optical video system VIC-3D and the method of correlation of digital images on polymer composite materials. Deformations at the structural and macroscopic levels are compared. Recommendations on the selection of post-treatment parameters, namely the step in the calculation by the KCI method, are proposed. A method of reducing the edge effect arising during uniaxial tensile testing of specimens with a concentrator is proposed. As a result of these studies, it becomes possible to obtain new experimental data on the processes of defect development and macroscopic fracture zones in the hole region, avoiding the influence of the edge zone.

Operation of mechanical engineering products operating under conditions of intensive wear at high rotation speeds and loads leads to their inevitable wear and significant metal losses. One of the methods for obtaining wear-resistant surfaces on products, for example, friction pair parts, is the microarc oxidation (MAO) method of aluminum alloys. The method allows obtaining dense hard surface wear-resistant composites based on α-Al₂O₃ (corundum) and γ-Al₂O₃. The structure, composition and surface quality of the resulting MAO coating significantly affect the performance characteristics of the product surface. The aim of the work is to determine the effect of porosity (10 and 16%) and surface roughness (R_a, equal to 2.7 and 0.51 μm) of MAO composites on D16T alloy on tribological properties and to evaluate the possibility of using MAO coatings in friction pairs, including end seals, under dry friction conditions. Comparative tests were carried out on an SMT-1 machine under dry friction conditions at a specific pressure in the friction pair of P = 0.5 MPa; the duration of the experiment was 90 – 91 min for each friction pair. The studies have shown that in many friction pairs, various types of damage (destruction) of the coating integrity, as well as deep abrasive wear, occurred. The porosity of the MAO coating in the range of 10 – 16% at different roughness values does not affect the abrasive wear of the coating. However, a porosity of 10% and a surface roughness of no more than R_a ≤ 0.51 ± 0.12 μm are preferable for achieving better tribological characteristics of surface MAO composites on D16T aluminum alloy.

Statements of problems of statistical analysis of data with a gamma distribution are related to classical mathematical statistics. Oddly enough, not all alone were solved within the framework of parametric statistics, which was at the forefront of the development of statistical science in the first third of the 20th century. As with the beta distribution, gaps need to be filled. This is necessary because the gamma distribution is currently widely used in theoretical and applied work. An example is GOST 11.011–83 «Applied statistics. Rules for determining estimates and confidence limits for gamma distribution parameters». The standard gamma distribution is determined by the shape parameter. When switching to a scale-shift family, scale and translation parameters are added. Seven formulations of parameter estimation problems are considered, since each of the three parameters can be either unknown or known. For each of the formulations, the estimates of the method of moments and their asymptotic variances are found. For a known shift parameter, maximum likelihood estimates are obtained. One-step estimates, asymptotically equivalent to maximum likelihood estimates, are used for an unknown shift parameter. The presence of measurement errors affects the accuracy of parameter estimates when applying certain calculation algorithms. In GOST 11.011–83, based on the interval data model, rules are given for choosing an estimation method for unknown shape and scale parameters and a known shift parameter. During the development of GOST 11.011–83, problems were identified, for the solution of which new methods from a scientific point of view were proposed. Further development of new scientific results obtained in the course of solving a practical problem (development of GOST 11.011–83) led to the creation of new scientific directions. We are talking about the statistics of interval data, as well as one-step estimates. To date, the statistics of interval data as a branch of mathematical statistics is quite developed and covers all the main areas of statistical methods. It is an important part of systemic fuzzy interval mathematics.