No 4 (2015)

Ni-Al alloys are considered the materials with high-temperature shape memory effect. However, being in coarse-crystalline state, Ni-Al alloys have low ductility. By performing grain refinement, it is possible to improve the alloys ductility. For example, it is possible to use the ultrarapid crystallization on revolving drum. The grain refinement will cause the structure dispersion.

In this paper, the authors made an attempt to detect a 14M martensite in Ni-Al alloys - Ni_62,5Al_37,5, Ni­­₆₄Al₃₆, Ni­­₆₅Al₃₅ and Ni₅₆Al₃₄Co₁₀ (at. %) - produced by melt spinning on the revolving steel drum.

Tape samples having thickness of 30 µm and the grain-size of 0,5–4 µm were produced in the result of rapid crystallization. Using the resistometric measurement, the authors determined the temperatures of the direct and the reverse martensitic transformations in all alloys under examination. The authors could determine the martensitic transformation temperatures in Ni­­₆₅Al₃₅ and Ni₅₆Al₃₄Co₁₀ alloys only with the help of rapid heat at the rate of 75 ºС/min, as during the slow heat at the rate of 1–5 ºС/min the maraging with the А₅В₃(Ni₅Al­₃) type phase takes place, which causes the loss of martensitic transformation reversibility. The alloys’ structure is studied with the help of transmission electron microscopy. At room temperature, Ni­­_62,5Al_37,5 alloy stays in metastable austenitic condition with B2 lattice and Ni­­₆₄Al₃₆, Ni₆₅Al₃₅ and Ni₅₆Al₃₄Co₁₀ alloys go through martensitic transformation. The structure in Ni₆₅Al₃₅ and Ni₅₆Al₃₄Co₁₀ alloys consists of plate martensite depleted of inner fine-scale twinning, whilst the Ni­­₆₄Al₃₆ alloy structure consists of thin-plate martensite and retained austenite. According to the microdiffraction data, martensite in three alloys is recognized as martensite with L1₀ lattice. Using the radiographic analysis, the authors determined in Ni­­₆₄Al₃₆ and Ni­­₆₅Al₃₅ alloys a small amount of 14M martensite as well as the major martensitic L1₀ phase and the retained austenite.

There are two radically different approaches to the engineering problems solving. The essence of one approach consists of the optimization of engineering solutions parameters using some known algorithm, for example, mathematical or some other modeling. The other approach is based on the creation of a new engineering solution using technical creativity. While solving challenging tasks both approaches are applicable. The aim of this research is to identify the correct balance of technical skills with regard to optimization and technical creativity.

Optimization of technical object parameters can be reduced to the search of their best combinations at the objective function extreme values and meeting the requirements of the defined engineering constraints. As a result, a task comes to the solution of the system of mathematical model equations and inequations.   

However, the solution of mathematical model allows determining the object optimal parameters only in terms of specified constraints. The expansion of the constraints boundaries is possible only by the creation of new engineering decisions. It can be achieved through the identification and resolution of contradictions contained in the problem, in other words, by applying the methodology of technical creativity.

The examples show that the most effective solutions to engineering problems result from the combination of the object parameters optimization and the technical creativity methods.

The described approach to the problems solving is applicable to the standard engineering activity. The authors suggest applying the received data in the higher educational institutions and in training centers of industrial enterprises for training technical engineering personnel. The application of the proposed study will increase the qualitative approach of engineers while solving engineering problems, as well as improve the level of training of specialists.

Ensuring the set level of acoustic comfort in passenger compartments of motor vehicles (hereinafter – MV) and low levels of external noise represents the important direction in their design and improvement. One of the important tasks in this process is the development of the objective criteria that characterize the attainable level of acoustic comfort of the developed construction of a vehicle. Well-known methods and objective criteria for assessment of acoustic comfort are characterized by limited load and high-speed modes of operation, complexity of interpretation and ranging of the obtained results, and insufficient correlation with results of the subjective expert opinion. The paper analyzes results of experimental studies of internal noise of 70 models of motor vehicles (cars) of the domestic and foreign manufacturers executed in road and bench test conditions. Road acoustic tests were carried out on public roads, moving with intensive acceleration, stabilized speeds, and motion with the engine switched off. Bench acoustic tests were carried out on motionless samples of motor vehicles in the conditions of a full-scale whirl tube and a big semi-anechoic acoustic chamber. In the course of analysis of the obtained results the researcher assesses statistical distribution of the studied parameters; the nature of their change depending on the load and high-speed modes of operation; chronological tendencies. The studied samples of MV are ranged into four categories of acoustic comfort in each of the studied modes of acoustic tests. The model of formation of a complex index of MV acoustic comfort has been developed based on the parameters of noise levels, levels of sound pressure at frequencies of motor harmonicas, and articulation indexes. Contribution of each of the acoustic parameters measured on various modes of tests is defined by empirical coefficients of weight. Objective criteria of ranging the acoustic parameters in various load and high-speed modes of operation can be used in technical requirements to design of the new and modernization of the existing models of MV. The complex index of acoustic comfort is offered to be applied for determination of competitiveness level and perfection of MV design within the target group of analogs.

One of the main tasks of oil producing industry is the increase of producible oil index and the oil-field development rate. In the context of hydrocarbon crude stock reduction and the increasing energy consumption, the issue of hard to recover reserves development occurs and the high-viscosity heavy oil rates are considered to be such reserves. Chemical agents (resolvents) addition, mechanical effects, magnetic and electrostatic fields imposing, and thermal treatment are the basic methods of oil viscosity reduction. The main method of heating and viscosity reduction of hard to recover oil rates is the application of gas producers, which operate using solid fuel. The use of ballistite fuels in gas producers with the possibility of adding various coolants of different concentrations allows regulating temperature and emission characteristics of homogeneous combustion products to the level specified by the recovery methods. The paper presents the methods and the results of heat emission calculation of the combustion products of a gas producer that operates using solid fuel. Water is used as a coolant. The combustion products are represented by the aggregation of monodisperse system of sootflakes and gas phase. Using the method of computing experiment, the authors studied the influence of a coolant concentration (0 %, 10 % and 25 %) on the temperature and spectral and integral emission parameters (fluence rate and emissivity factor) of combustion products at different pressures (0,1 MPa and 7 MPa). It was established that the cooling agents addition influences on the fluence rate value more than the emissivity factor when the combustion products have only gas phase. The growth of soot content causes the increase of spectral and integral emission parameters even when adding agents lowering combustion products temperature. The authors present the characteristic curve of integral parameters on the emitting layer thickness.

The study of the parts fracture surface is the basic and important part of determination of the fracture process causes and chronology. The quality and objectivity of fractographic analysis depends largely on the effectiveness of tools used for the fracture study. The main disadvantage of traditional methods used in this area is the two-dimensionality of images that greatly complicates the quantitative analysis of the fracture surface. In this context, the method of confocal laser scanning microscopy (CLSM) is one of the prospective techniques providing a high-quality measuring accuracy of the objects surface geometry in three-dimensional space, a wide scanning range along the vertical axis and the necessary depth of field. Moreover, CLSM method does not require the electrical conductivity and special specimen surface preparation, as well as the presence of vacuum.

In this study, the authors developed and tested the technique of exposure and further impact specimen fractures analysis using the CLSM. To be the subject of research, the authors selected the fractures of fully brittle and fully ductile fracture surfaces of 20 grade steel, the fractures of which were obtained during impact tests of the specimens hold at the temperatures of -196°C and +150°C, respectively. During the research, the optimal amplification, the lens type, the scanning pitch and the image noise filter were determined. The research showed that to measure the fracture surface ductility it is possible to use such parameter as the characteristic fracture surface area Sr, which value changes significantly while going from ductile to brittle fracture. The research showed that the CLSM application allows converting the qualitative analysis of metal products fracture into quantitative one improving the objectivity and accuracy of fractographic analysis.

The paper considers the issue of wear resistance improvement of small-sized cutting tools. One of the advanced ways to solve this problem is the heat treatment using the highly concentrated energy flows created by laser beam. Modern fiber optic lasers combine high power density of laser radiation with the possibility of laser beam delivery to the most hard-to-reach treated areas by using optic fiber. The study and forecasting of the properties and the structure of a modified zone are the most important elements of technological process preparing and allow selecting optimal modes of laser treatment. 

The paper gives the results of experimental study of the influence of laser modification parameters on the state and properties of the surface layer of the high-speed R6M5 steel samples. The authors obtained the dependences of heat-affected zone depth and width on the laser radiation power, measured the microhardness of various areas of treated surface and studied in details the structure obtained for various laser modification modes. The study revealed the increase in microhardness resulting from the fiber optic laser modification during the quasi-continuous operation and set the boundary between the modes of laser modification with flashing and without it for R6M5 tool steel. As the practical application of the results obtained, the authors carried out the evaluation of small-sized tools wear resistance according to the suggested modes and determined the laser modification modes allowing the increase of durability of small diameter twist drills in 5 and more times. Test results demonstrate the unavailability of some relevant modes for the tool working surfaces modification due to the extremely gross wear of the processed surface and the cutting edge damage within the cutting process.

Stumps lowering to the ground level using the working bodies of active action is the resource saving and environmentally safe technology in comparison with the other machine methods. At the same time, the existing devices for stumps chopping are unable to remove their underground part because of the abrasive properties of the ground. To avoid this disadvantage, the authors developed a device, which serves for the preliminary preparation of stumps for their lowering below the ground surface by creating patches-cavities and stumps cleaning from the ground and includes patch-maker, which has flexible working bodies allowing ensuring high cleaning completeness.  Steel-cable pieces were selected as the flexible working bodies, and the optimization of their parameters includes the determination of the working part type, diameter and length when the steel-cable rigidity, flexibility and elasticity reach the level required for the high-quality performance of the technological operation. In order to study the process of stumps cleaning from dirt and to determine the regularities of interaction of flexible working bodies with the stumps side surface, the authors developed the methodology of laboratory experiment, which allows varying of different patch-maker parameters values for determination of their influence on the completeness of the stumps side surface cleaning and the power consumed by a machine during the working process. The authors developed a laboratory machine that includes a frame, a roll with steel-cables, a hydromotor and a hold for a stump and allows carrying out tests, the results of which will be used for revealing the dependencies of measures of work efficiency of a patch-maker on its design and traveltime parameters and for the optimization of its flexible working bodies and technical process parameters. 

The importance of the issue reflected in the paper is directly related to the social changes currently occurring in Russian society, the main indicator of which, as a rule, is youth. Moreover, the study of the issue is important in connection with the ongoing debate about the nature and dynamics of the civil society in modern Russia. This paper defines the essential characteristics of youth involvement into civil society development. Theoretical problem of the work is determined by the approach of H. Ortega-and-Gasset. Thus, the main objective of the paper is to answer the question – what the involvement of youth into civil society development is. The paper analyzes the existing definitions within the Western and domestic scientific community of such concepts as youth, civic involvement and civil society; emphasizes the importance of studying the classification of the “participation” concept. The analysis discovered that, despite numerous works devoted to the phenomenon of involvement, the term itself is used by researchers in different contexts, and is filled with different contents. Particular attention is paid to the problem of relation between the key types of involvement, such as civic, political, public and social. Following the results of the analysis, the author has determined her position concerning this issue, where youth involvement in the civil society development is defined as the introduction of a number of rules, regulations, and self-organizing technology for youth, which in their turn are based on the voluntary co-operation with all sorts of actors and stimulate freedom, equality and solidarity ensuring.

The paper researches linguistic units used to verbalize the author in academic discourse. It is a case study of 40 academic papers (10,000–12,000 words in each) in Humanities published in English- and Russian-language journals. The paper distinguishes between three discourse roles of the speaking subject in academic discourse: a researcher, an opinion-holder, and a representative. The paper also compares the frequency with which the linguistic units are used to represent the subject in English and Russian texts. The analysis shows that the Russian authors prefer representing their roles with the first-person plural pronoun as well as implying themselves in subjectless constructions. In English papers, the subject can be verbalized with the first-person singular pronoun, but the most frequent marker is the personified point of view construction. We conclude that the implication of the speaking subject in order to give objective tone to the discourse is typical of both English and Russian papers. The article applies quantitative and qualitative methods, and a comparative analysis. The research is of practical value for the Russian authors who should adhere to all the standards of the English-speaking academic community when preparing their papers for English-language journals.