Classification of the surfactants being a part of detergents by dissociation of their functional charged group in an aqueous medium is considered. Surfactants are complex multicomponent mixtures consisting of homologues of surfactants and impurities of starting materials. An exploratory analysis of this type of raw material, which is a laborious analytical task, is carried out mainly by chromatographic methods. Gas chromatography (GC), high performance liquid chromatography (HPLC), gas chromatography in combination with mass spectrometry (GC-MS), high performance liquid chromatography in combination with mass spectrometry (HPLC-MS) and thin layer chromatography (TLC) are used depending on the structure and specificity of the analyte. A review of the research data in this field over the past 10 years is presented. HPLC is the most common method for studying surfactants. This method allows quantitative and qualitative determination of non-volatile analytes with both small and large molecular weights without preliminary derivatization. When using the GC method, the analyte must be converted to volatile compounds, which considerably complicates the stage of sample preparation. However, this method makes it possible to obtain a complete separation of the homologs and isomers of many surfactants. In combination with MS, it is possible to obtain specific structural fragments of the surfactant molecules. TLC method is widely used for qualitative determination and separation of surfactants. This method is mainly used for group identification of surfactants. The studies thus cponsidered were aimed at developing new and modifying existing methods; search for optimal chromatographic conditions, derivatizing agents, separation columns, etc.

We present a technique of multi-element analysis of new corrosion-resistant titanium alloys doped with ruthenium using Optima 7300 DV ICP-AES spectrometer (Perkin Elmer Corporation, USA) and microwave system Speedwave FOUR (Berghof Products, Germany). Compositions of the acid mixture as well as the temperature and time parameters of the sample preparation of titanium alloys under microwave heating in an autoclave which ensure a complete quantitative transfer of the sample into a convenient analytical form for subsequent ICP-AES analysis without loss of volatile components are substantiated. Optimal conditions of excitation of the analytical signal of analytes for ICP-spectrometer are specified and analytical lines of the elements free of spectral interference are chosen for determination of all critical components in corrosion-resistant titanium alloys. The studies were carried out using samples of experimental melting of industrial titanium alloys of different classes, which, due to volumetric doping with ruthenium, are under development and are not yet commercially available in Russia (grades of alloys PT-7M+Ru, PT-3B+Ru, 5B+Ru, 37+Ru, BT-22+Ru). The samples contained the following alloying elements (% wt.): Al (1.8 – 6.3); V (1.0 – 5.5); Mo (0.7 – 5.5); Zr (0.2 – 3.0); Cr (0.5 – 1.5); Fe (0.5 – 1.5); Ru (0.05 – 0.15). The correctness of the alloying element determination is confirmed by analysis of standard samples using the method of sample variation and spike test for ruthenium determination. The developed technique significantly shortens the duration of the analysis due to combination of the multi-element method of ICP-AES with microwave sample preparation, expands the list of detectable elements in titanium alloys, and increases the accuracy of Al, Si, V, Cr, Fe, Ni, Cu, Zr, Nb, Mo and Ru determination in titanium alloys in critical(rated) ranges of concentrations.

A method of chromato-mass spectrometry is used to study the impurity composition of monosilane obtained in the reaction of magnesium silicide with ammonium chloride in liquid ammonia. To improve the reliability of the impurity identification along with the study of pure monosilane samples we analyzed monosilane fractions isolated upon purification by low temperature rectification. To separate the impurities of permanent gases, hydrocarbons C₁ – C₃, volatile inorganic hydrides, disilane, and alkylsilanes we used an adsorption capillary column GS-GasPro 60 m × 0.32 mm with a modified silica gel. To separate the homologues of monosilane, siloxanes, and alkylsilanes we used a column 25 m × 0.26 mm, d_f = 0.25 μm with a polytrimethylsilylpropyne (PTMSP) sorbent. Identification of the impurities was performed by comparison of their experimental mass spectra with the NIST database. In the absence of the mass spectra of analytes in the NIST electronic database or a low coincidence of the spectra identification was performed using data of mass spectra and retention time published in the literature. The impurities of permanent gases, carbon dioxide, hydrocarbons C₁ – C₃, volatile inorganic hydrides, monosilane homologues, siloxanes, and alkylsilanes were identified in monosilane. Quantitative determination of the impurities was carried out in the mode of selective ion detection by the mass numbers having the maximum signal/noise ratio. Calculation of their concentrations was performed using a method of absolute calibration by the peak areas. The concentrations of the impurities in the lack of reference samples were determined using the dependence of the sensitivity coefficients of their detection on the magnitude of the total ionization cross sections. The detection limits of the impurities range within 1 × 10^–5 — 2 × 10^–7 % mol. The accuracy of the analysis was confirmed by the method of sample size variation. The results of determination of the impurities in monosilane after synthesis, in that purified by low temperature rectification, and in the isolated fractions with concentrated higher- and lower-boiling impurities.

We present the results of studying sorption processes in metal hydride pairs. Technique and laboratory setup are developed for experimental study of kinetics and determination of the duration of interaction between hydrogen and hydrides formed upon saturation of two intermetallic compounds (IMC) of different compositions. The design of the setup and principle of operation are presented. The setup includes two steel retorts which contain the alloys capable of multicycle reversible sorption of hydrogen with formation of the high- and low-temperature hydrides. The system provides measurements of pressure in the hydrogen pipeline between the retorts and temperature of circulating or stirred heat carriers which cool the retorts during sorption and heat them during desorption. The dynamics of hydrogen pressure change in the pipeline and temperature of the heat carrier under simultaneous operation of two hydrides of alloys Mm_1–yLa_yNi₄Co and LaNi_5–xAl_x are studied. The duration of hydrogen desorption from the first hydride with simultaneous sorption by the second one is determined. The thermal balance for the low-temperature module of the setup was calculated to prove the obtained kinetic characteristics. Similar results were obtained for desorption of hydrogen from high-temperature metal hydride. The technique and results can be used for simulation of sorption processes in metal hydride pair and determination of the parameters of optimal design for efficient operation of sorption heat pumps.

We present a technique of measuring hysteresis loops of the amorphous microwires using a method of vibrating-sample magnetometry. Control magnetic measurements were carried out on samples of an amorphous microwire of Fe₇₅B₁₃Si₁₀C2 composition in a glass shell obtained by the Ulitovsky – Taylor method. The sample was fixed on a specially manufactured experimental setup which enables us to stretch the microwire by means of suspended loads. Fixation of the microwire in the stretched state was carried out by the glue. The stresses in the metal core of the microwire formed upon stretching with suspended loads, as well as the stresses in the contact area of the wire and glue are calculated. The developed method provides fixing of tensile stresses in wires even when the value of stresses may attains a few GPa.

Morphological parameters of digital images of the materials used in powder 3D-printers are studied. Digital images of polymer samples were obtained in transmitted light using an optical microscope equipped with a digital ocular camera. Morphological analysis of images is carried out using the program ImageJ 1.45s. Statistical and correlation analysis of primary and secondary powders for layer-by-layer laser sintering based on polyamide-12 was carried out using Statistica 10 software package. The fact of agglomeration of coarse particles in a secondary powder is established, which leads to a change in the fractional composition and is one of the reasons for violation of heat transfer upon laser sintering during printing. Violation of the fractional composition can greatly change conditions of heat exchange in the laser focus zone and affect the quality of the finished products. It is shown that data on the area of the projection of the particles, their perimeter and Feret’s diameter obey the normal distribution law. The area of the projection of the powder grains is proposed to be used as an analytical signal, whereas the value of Pearson’s criterion greater than the minimum and corresponding to the degradation of the powder mixture with an unacceptable probability of production rejects — as a criterion of the suitability of the working mixture. Analysis based on the calculation of the correlation coefficient takes no more than 30 min and can be recommended as a rapid procedure for controlling the quality of a mixture of powders for printing.

The feasibility of using video measuring machines for detection and measurement of the defects such as microcracks in the materials (polymers, quartz and organic glasses) of aviation duty is considered. As the aforementioned materials are characterized by low reflectance detection of the microcracks in them is problematic but rather important task because the microcracks present can cause an accident or wandering defect. Threshold (critical) values of the defects which can be revealed by means of such machines of two different models are determined, e.g., the minimal length of the detectable cracks, which can be used as a parameter of the product rejection. Because of the prohibition of carrying out the studies on the real objects we used a technique of provoking defects by indentation. The results of using classical methods (ultrasound, etc.) and data on the defect detection by the developed procedure were compared. The informativeness of the developed methods was increased using the developed techniques, e.g., by contrasting of the microcracks.

The reasons for destruction of fasteners made of steel 30KhGSA are analyzed. It is shown that in case of destruction of bolts in the package connecting frame elements, damage of bolts results from fretting corrosion, attributed to mutual friction between bolts and elements of skin, belt and tape. Fretting corrosion develops in the sites where cadmium coating of bolts is damaged upon friction. The occurrence of fracture in the belt, skin and tape is promoted by break-in scuffing of the openings and corrosion damages (fretting corrosion) triggering the intergranular fracture, most severe in the skin and tape. The reason for damage arises from structural and technological factors: increased stresses present in the package, micro-displacements of the mating parts, violation of the cadmium coating, insufficient corrosion protection and environmental impact. Destruction of self-locking nuts made of 30KhGSA steel with anti-corrosion cadmium coating used in the assembly of the auxiliary gas turbine engine is attributed to their significant overheating, i.e., the impact of molten coating on the surface of loaded nuts and the penetration of the liquid metal into the base material along the grain boundaries. The use of cadmium coatings in operation of steel parts at a temperature exceeding (even briefly) the melting temperature of Cd (T_melt = 320.9°C), under conditions of contact with stressed metal due to the Rebinder effect, leads to a sharp loss of strength and premature failure of the part. Study of the destruction of galvanized bolts made of 30KhGGSA steel during the repeated-static testing revealed that several factors contribute to the onset of fatigue multiple site damage: presence of the rough risks; sandblasting, performed before galvanizing using large sand fractions, which contribute to the premature origin of cracks; areas with deposits formed upon coating with a loose adhesion of the layer. The presence of a large number of pits along with the fatigue grooves indicates to high load of the bolt material upon operation. The study was carried out using optical and scanning electron microscopy and X-ray microanalysis.

Experimental studies of the physical and mechanical properties of «factory» and «field» types of cast-resin insulation material are carried out in the framework of scientific research regarding the reliability and safety assurance of cast-resin insulated busbar systems. Insulation of the «factory» type (FT) is used in manufacture of sections of the busbar system, whereas insulation of the «mounting» type (MT) is used to isolate the joints of sections during their installation. Analysis of the operational factors revealed a set of the physical and mechanical properties of cast-resin insulation material which affects most strongly the strength of the busbar system. The studies included determination of the elastic characteristics and ultimate strength by the method of static mechanical tests of flat specimens for tension and three point bending. The tests were performed at low, zero and high temperatures according to operation modes of the busbar system. The coefficients of linear thermal expansion of the material for two temperature ranges were determined using rod specimens. The density of the material was measured by measuring size and weight of the specimens. All experiments were carried out using the methods listed in state standards. The results of the experiments showed a distinct effect of temperature on the Young’s modulus and the ultimate strength of the insulation material in bending tests. The ultimate strength of the MT insulation is 7 – 30% higher compared to FT insulation due to the fine and more uniform structure of MT insulation. As a whole, the mechanical properties determined in the experiments are significantly lower than the mechanical properties declared by the manufacturer. This can lead to reassessment of the strength of cast-resin insulation during safety control of busbar systems considering the declared values of the mechanical properties. In this regard, the obtained results should to be taken into account in calculation of the stress-strain state of the busbar systems with cast-resin insulation at different operation temperatures.

The goal of the article is a mathematical generalization of S. Ya Yarema formula derived for approximation of the experimental diagrams of the fatigue fracture and subsequent analysis of the capabilities of the formula. The analysis is performed on the basis of the operator for smooth transition from one mathematical function to another. Formula of S. Ya Yarema is shown to be a special case of this mathematical operator when a smooth differentiable transition occurs from one constant level of the amplitude of stress intensity factor to another constant level. The obtained mathematical expressions can be interpreted as the cumulative probability and the probability density of random values of the fatigue crack rate. This allowed us to give a statistical interpretation of the fatigue fracture diagrams. On this basis we developed a methodology for estimation of the residual resource of a structural part containing a fatigue crack.

Streamlining the results of scientific research entails the necessity of the uniform understanding of terminology, accumulation of facts and insight of the development trend. We consider those issues on the example of «regression analysis model (recovery of the dependencies)» to form a unified methodological base for discussing various particular issues in this field. Four methods are considered. The models of the method of least squares with deterministic independent variable are singled out. According to the new paradigm of applied statistics, the distribution of deviations (errors, discrepancies) should be considered arbitrary, with one restriction, to obtain the limiting distributions of the estimates of parameters and dependencies, it is expedient to assume the fulfillment of conditions of the central limit theorem. The second basic type of probabilistic-statistical models of the method of least squares is based on a sample of random vectors. The dependence is nonparametric and distribution of the two-dimensional vector is arbitrary. Estimate of the variance of the independent variable can be considered only in a model based on a sample of random vectors, as well as the coefficient of determination as a criterion for the quality of the model. The issues of smoothing time series are discussed. Methods of reconstructing dependencies in spaces of general nature are considered. It is shown that the limiting distribution of the natural estimate of the dimensionality of the model is geometric, and construction of the informative subset of features comes across the effect of «inflation of the correlation coefficients». Different approaches to the regression analysis of interval data are discussed: the approach of confluent analysis becomes a thing of the past. An analysis of the variety of models of regression analysis leads to the conclusion that there is no single «standard model». Critical analysis of the hardened beliefs is necessary for competent development and application of mathematical methods of research, in particular, for transition to a modern paradigm of applied statistics.

Criteria for conducting expert estimates at the stage of outlier identification in the procedure of A- and B-basis calculation of the strength characteristics of the polymeric composite materials (PCM) are considered. Statistically-valid A- and B-basis values are lower bounds of 95%-confidence interval of the first and tenth percentile of the characteristic distribution, respectively. Basis values reflect not only the interrelation of mean and variance, but also parameters of the sample they were calculated from: sample size, probability distribution type, compatibility of data. At the steps of testing the hypotheses carrying out expert assessment is provided of in an original algorithm of bases calculation, and a number of criteria for each of steps is also offered. Practicability of application of the additional criteria promoting making the reasonable decisions allowing to increase reliability of designs from PCM is shown. An example of use of the procedure of decision-making is in detail reviewed in the analysis of results of interlaminar shear strength testing received at incoming inspection of HexPly prepreg; the maximum shear strength value of one from five specimens of one from seven batches of a prepreg was statistical outlier for the pooling data set. Recommendations about expert estimation of three basic and four additional criteria are provided. Along with a research of compatibility of data and approximating distribution type, the procedure of outlier analysis is successfully used at a stage of the exploratory data analysis, and also at quality control of material fabrication and testing process.