The frontier of electron probe x-ray method in determination of the trace quantities of metal on a silicon substrate is studied. Experimental data are obtained for ultra-thin chromium films on a silicon substrate. It is shown that the signal - noise ratio significantly increases at a strong inclination of the sample (80°) which provides determination of extremely low (for this method) chromium content. Calibration curve for inclined sample position is obtained using Monte Carlo method. Surface concentration of chromium atoms (2.2 ± 0.5) × 10¹⁴ cm^-2 and chromium detection limit (5 × 10¹³ cm^-2) are determined experimentally for the given configuration of the experiment. For electron-probe microanalysis of bulk samples this is a record value. The equivalent mass of chromium at aforementioned value of the surface concentration is approximately 4 × 10^-18 g. Implementation of the method does not require changes in the of the device design.

At present, the amperometric determination of oxygen concentration using the Clarke electrode is surely replaced by an optical method based on dye phosphorescence quenching by molecular oxygen with subsequent conversion of the lifetime of the excited state into the concentration value using a calibration curve. The first domestic serial analyzer «Expert-009» based on the aforementioned principle was included in the State Register of Measuring Instruments in March 2016. The sensitive element of the sensor is a polymer film with a dye (fluorine-substituted porphyrin metallocomplex) distributed therein. The matrix material should be resistant to highly active singlet oxygen formed during measurements. Here, we study a possibility of using polyhexafluoropropylene (PHFP) as a matrix material. The metrological characteristics of the sensor are determined: the accuracy figures do not exceed 5% and 8% for isothermal measurements (25.0°C), and for the measurements within a temperature range of 5 - 35°C, respectively.

A key feature of the analytical control in industrial production is a constant striving for automation and shortening of the time of analysis. Optimization of the sample preparation which is the most time-consuming and inaccurate stage of any chemical analysis is first required to achieve the goals. The case study of NPKS-fertilizer using x-ray fluorescence analysis (XF) is presented to assess different methods of sample preparation. A matrix «object - characteristic feature» is compiled for NPKS fertilizers and most informative indicators are specified for ranging analysis of the particles in size in pressed sample. The line intensities of middle (by atomic mass) elements, potassium in particular, are considered the most informative features for this purpose. Statistical indices are calculated for each type of sample preparation.

A method for determination of hydroxyl number (HN) of bifunctional polyethers (polyethylene glycols) in the range from 28 to 380 mg KOH/g by melting point T_melt using differential-scanning calorimetry (DSC) is developed. Provided that the functionality of the polyester is constant (f = 2), T_melt exhibits a linear dependence on the hydroxyl number of polyester. The method was tested in the analysis of industrial PEG samples.

The technique of atomic-emission determination of boron in aluminosilicate-based catalysts is described. Spectrum excitation conditions are specified. Proper choice of the calibration samples and fluorine-containing carrier in the spectral buffer provided more accurate results of analysis with a rather low error of 11% rel.

Lacks of penetration, pores, etc. often formed upon socket welding of polypropylene pipes adversely affect the weld strength. At the same time, welding is allowable at a positive ambient temperature. We present the results of studying weld strength for conditionally divided zones along the length of socket welded joints obtained at different ambient temperatures and various welding modes. At a negative temperature of ambient air welding of polypropylene pipes PPRC PN10 63 × 5.8 is carried out according to the technology developed at the Institute of Oil and Gas Problems SB RAS. Indicators of the strength of socket welding are obtained in tensile tests of blade specimens and ring specimen testing for shear by compression.

A method for calculation of the specific dynamic capacity Q_i of sorbents upon sorption purification of flowing solutions at any time is presented. The method is based on the assumption that any isotherm of sorption from flowing solutions includes three characteristic sections: i) initial section of complete sorption of the ecotoxicant (the sorption coefficient ρ is equal to 1) which can be absent on the isotherm if the adsorbent is incapable of complete extracting of the adsorbate under given process conditions; ii) on the next time interval of the sorption isotherm ρ is a linear function of the process duration ρ = f(τ), which is observed rather often; iii) on the third time interval of the sorption isotherm ρ = 0, since the entire dynamic capacity of the sorbent is depleted to the onset of the interval. This approach allows us to obtain the equation of the sorption process on the second interval using the coordinates of two characteristic points. The developed provides estimation of the Q value with the accuracy not inferior to the experimental data, and substantially simplifies the practice of continuous sorption purification of drinking, technological and waste waters. Examples of experimentally observed sections of sorption isotherms and the specific features of calculating the dynamic capacity of the sorbent on each of them are presented.

We present a methodology of studying particle size distribution of Ce-doped YAG (yttrium aluminum garnet) powders by laser diffraction method based on the difference in the character of laser beam scattering by the particles of different size. Since the measurements are taken in a flow of dispersion medium, powder aggregation probably occurred during measurement procedure can result in overvaluation of the particle size in the distribution thus obtained. Different dispersion media (water, ethanol, isopropanol) and additives (Na salts and commercial surfactants) are used to lower powder aggregation. Most of the modified systems demonstrate reduced agglomeration of the particles during measurement procedure compared to standard «water - powder» dispersion system. The best and most stable results are obtained in isopropanol or water added with phosphate-based electrolyte which effectively prevent aggregation. Addition of surfactants appeared ineffective with regard to the stability of the results. Water with addition of sodium orthophosphate is proposed as the most convenient medium, in which dispersion is stable and all the components are readily available.

A passivation action of a phosphate electrolyte used as a P-2 rust converter during painting on a rusty surface, as well as the effect of inorganic and organic additives on the passivation region of U8A steel and the properties of the protective film formed on the surface are considered. The shape of anodic polarization curves obtained on the sampled with a preformed film indicates that introduction of the additives hinders the anodic process. Cathode polarization curves show inhibition of the cathodic process. A region of the passive state of steel U8A is observed in the media of the rust converter. Introduction of the considered additives into a P-2 rust converter improves the protective properties of the passive films on steel: the onset passivation potential decreases by 20 - 40 mV, the yield of metal up to 60% compared to the background, and the films thus formed exhibit high electrical insulating properties. The most effective additives and their optimal concentrations are specified for developing coatings with improved protective properties.

Reduction of noxious emissions and increase in oil drain intervals which reduce the maintenance cost of the vehicles and decrease a negative impact on the environment is one of the main trends in the modern automobile industry. The goals are achieved through introduction of the new systems and modes of engine operation, which in turn increases the rate of oil pollution and speeds-up degradation of the motor oils. Periodic monitoring of the oil characteristics can prevent the engine failure and reveal a decrease in the motor oil performance in due time which entails the necessity of developing the new methods for rapid analysis of motor oils. The development of the element base and increase in the accuracy of measuring devices provide their adaptation for determination of the qualitative characteristics of the motor oil. Nowadays, there are available measuring devices providing measuring of the dielectric characteristics of the motor oil within a wide range. The possibility of using measurement data for determination of condition of the motor oil is considered. The results of studying motor oils of various basic bases through determination of dielectric parameters are presented. Correlation analysis revealed clear dependence of the dielectric parameters of motor oil on the soot content.

Critical analysis of the methods of testing for fracture toughness in corrosive media under long-term load is presented. Bearing in mind the shortcomings of the known methods, we develop a technique for estimating the fracture toughness of structural materials in corrosive media under the impact of a long-term static load which is set with a high accuracy on testing machine and then fixed with a spacer bolt. The method provides determination of the effective load in the sample at any time of the exposure, which predetermines the possibility of studying the kinetics of corrosion attack and change in the fracture toughness in conditions of prolonged static loading and corrosive media.

The size effect arising upon the load decrease from 50 kgf up to 0.05 kgf in measurements of the Vickers hardness for medium-grained (WC-8Co), submicron (WC-8Co-1Cr₃C₂) and ultrafine-grained (WC-8Co-0.4VC-0.4Cr₃C₂) hard alloys, as well as standard hard alloys T15K6 and VK6OM is considered. An increase in hardness resulting from the size effect attains 14 - 16%. Presence of the elevations near the penetrator indentation distorts the measurement results. The inverse dependence of hardness on the size of indentation is demonstrated. The largest dimensional effect is observed for the hardest ultrafine-grained alloy. The results of the fracture resistance measurements using Palmquist method for optical and raster microscopes are compared. It is shown that crack formation in the Palmquist scheme occurs under the impact of loads exceeding a critical value, which depends on the fracture toughness of the alloy. Annealing does not have a significant effect on the results of hardness and fracture toughness measurements. The results confirm a decrease in the crack resistance with increasing hardness due to reduction in the average grain size of WC sample when going from medium-grained hard alloys to submicron and ultrafine-grained alloys.

Experimental study of the scale factor impact on determination of the mechanical characteristics of metals and alloys in scratch indentation tests with recording «scratch intensity - scratch length» deformation diagrams is presented. The advantages of using the scratching method with a constant preset depth for control of the mechanical characteristics of materials and coatings are shown. The effect of the scratch depth on the determined values of the mechanical characteristics -scratch hardness and specific energy of local destruction - is studied in scratching tests using the edge of the Vickers tetrahedral pyramid. It is shown that the scale effect in scratching tests is manifested rather clearly. As the scratch depth decreases, the strain resistance, scratch hardness and specific fracture energy grow due to a multiple reduction of the elastic volume of the metal. For this reason, we recommend to use a constant preset scratch depth in comparative scratch testing of several materials or coatings thus providing close values of the elastic volumes of the materials and the same impact of the scale factor on the results of measuring the mechanical characteristics of the material.