Establishment of the dependence of the strength indicator of the composite material of pressure hoses on the character of single damages

Experimental studies are presented and the dependence of the change in the strength of the material of a pressure head fire hose of type T with an inner diameter of 77 mm in the longitudinal direction is established, taking into account single damages. The work describes the plan of the experiment and carried out a number of field experiments to determine the effect of the length ld and the depth K damage on the strength F of the hose material, that is, obtaining the dependence F=f (ld, K). A mathematical method of experiment planning was used and a plan was drawn up for a complete multivariate experiment of type 2k with an acceptable model accuracy of 5 %. The limits of variation of the factors are set taking into account a priori information, experimental capabilities and on the basis of the results of preliminary search experiments. The dependence in the coded and natural values of the factors is obtained. The reliability of the relationship was checked using the Fisher test, the calculated value of which was 5.98, which confirms the adequacy of the described process with a probability of 95 %. Analyzing experimental studies of the dependence of the change in the strength of the hose material on the length and depth of damage, it can be said that the change in the strength of the hose almost linearly depends on the specified damage parameters. It is found that with increasing damage, the strength of the hose material significantly decreases. When varying the length factor and the greatest depth of damage, K=0.4 mm, the strength of the hose material decreases from 11.67 kN to 8.77 kN, and in percentage terms by 25 %. The results obtained can be used in practical units of emergency rescue teams, when diagnosing hidden damage in pressure head fire hoses in order to prevent their failure in case of fires

LEXAS: a web application for life science experiment search and suggestion

Motivation: In cellular biology, researchers design wet experiments by reading the relevant articles and considering the described experiments and results. Today, researchers spend a long time exploring the literature in order to plan experiments. Results: To accelerate experiment planning, we have developed a web application named LEXAS (Life-science EXperiment seArch and Suggestion). LEXAS curates the description of biomedical experiments and suggests the experiments on genes that could be performed next. To develop LEXAS, we first retrieved the descriptions of experiments from full-text biomedical articles archived in PubMed Central. Using these retrieved experiments and biomedical knowledgebases and databases, we trained a machine learning model that suggests the next experiments. This model can suggest not only reasonable genes but also novel genes as targets for the next experiment as long as they share some critical features with the gene of interest. Availability and implementation: LEXAS is available at https://lexas.f.u-tokyo.ac.jp/ and provides users with two interfaces: search and suggestion. The search interface allows users to find a comprehensive list of experiment descriptions, and the suggestion interface allows users to find a list of genes that could be analyzed along with possible experiment methods. The source code is available at https://github.com/lexas-f-utokyo/lexas.

Checking the adequacy of polynomial dependencies of a single-phase asynchronous motor without external phase-shifting devices for ship automation systems

Статья посвящена сравнению результатов расчётов полиномиальных зависимостей однофазного асинхронного двигателя, полученных с использованием методов планирования эксперимента, с математической моделью построенной с помощью программ на ЭВМ на языке программирования Python. Актуальность работы заключается в том, что задачи аппроксимационного типа не всегда возможно решить, используя ЭВМ, поэтому исследователи часто применяют методы планирования эксперименты для решения таких задач и после уже стоят математическую модель на ЭВМ и проверяют адекватность полученных результатов. В результате в статье авторами предоставляется план проверки адекватности полиномиальных зависимостей однофазного асинхронного электродвигателя без внешних фазосдвигающих устройств для систем судовой автоматики. По итогу выполненной работы авторы приходят к выводу об адекватности построенной математической модели на ЭВМ с использованием языка программирования Python. The article is devoted to the comparison of the results of calculations of polynomial dependencies of a single-phase asynchronous motor, obtained using methods of experiment planning, with a mathematical model built using computer programs in the Python programming language. The relevance of the work lies in the fact that problems of the approximation type are not always possible to solve using a computer, therefore, researchers often use methods of planning experiments to solve such problems and after that they already have a mathematical model on a computer and check the adequacy of the results obtained. As a result, the authors provide a plan for checking the adequacy of the polynomial dependencies of a single-phase asynchronous electric motor without external phase-shifting devices for ship automation systems. As a result of the work performed, the authors come to the conclusion about the adequacy of the constructed mathematical model on a computer using the Python programming language.

Creation of innovative technologies for transport operations in the preparation of rough feed

The article deals with the influence of technologies for carrying out transport operations in the preparation of rough feed (hay, as well as valuable varieties of straw) on their quality and efficiency indicators of the entire technological process. To improve the quality of these operations, a combined transport technology has been proposed. During its development and research, the methods of simulation modeling, experiment planning and correlation-regression analysis were used. Regression equations were obtained in the form of the Cobb-Douglas function. The proposed innovative technology for combined transport of forage has proven its effectiveness during production tests in private conditions of agricultural enterprises. Evaluation of economic efficiency through the cost of transporting one ton showed an effect of 7-15%, depending on the quantitative and brand composition of the complex. This technology makes it possible to increase the efficiency of forage procurement, which affects the efficiency of animal husbandry and food security of the country.

Choosing the flow part geometric shape of the dredge pumps for viscous fluids

Purpose. Search for the possibility of increasing the efficiency of dredge pumps for viscous fluids by determining the rational values of the blade-outlet inclination angles in the pump impellers. Methods. During the research, the following is used: theoretical studies of the structure of the viscous fluids flowing through the flow part of dredge pumps; the method of three-dimensional software-simulation modeling of hydrodynamic processes using the Ansys software package; the methods of rational experiment planning for selecting the values of the number of points in the computational grid when optimizing the geometric parameters of the dredge pump impellers; methods of mathematical statistics and correlation analysis. Findings. It has been proven that the main reason for the failure of the flow part components in the dredge pumps is the manifestation of the influence of cavitation processes, which can be eliminated by changing the blade-outlet inclination angles in the pump impellers. A software-simulation complex for the automated design of the flow parts in the dredge pumps has been developed based on the use of optimization algorithms and computational fluid dynamics methods, which makes it possible to design dredge pumps with optimal characteristics that ensure their efficient operation with maximum efficiency values. It has been determined that one of the main factors influencing the head developed by dredge pumps and the efficiency value is the blade-outlet inclination angle in the pump impellers. Originality. Scientific novelty is in the scientific substantiation and development of a simulation-mathematical method for calculating the geometric parameters of the flow part in dredge pumps for viscous fluids at the design stage. Practical implications. The developed method for determining the rational blade-outlet inclination angles of the impellers in the dredge pumps for viscous fluids can be recommended to scientific-research and industrial organizations for use in the improvement, design and operation of the dredge pumps.

Study of Wear and Redistribution Dynamic Forces of Wheel Pairs Restored by a Wear-Resistant Coating 15Cr17Ni12V3F

The relevance of this study lies in the need to research the wear process of the elements of dynamic systems and to establish the dependence of the geometric and structural characteristics of wheels restored by plasma surfacing with a coating of 15Cr17Ni12V3F on dynamic, cyclically varying loads. The study was aimed to establish the dependencies between the deviation of the wear area, the formation of contact and fatigue stresses, and the change in the phase structure of the wheel defect. It is important to justify the permissible limits of wear of the transverse profile in the contact zone of a wheel and ridge. The object of the study was the dynamic interaction of the “wheel–ridge–rail contact surface” system. To achieve the goal, the following methodology was adopted: kinematic analysis, strength calculation, the use of mathematical analysis in dynamic system modelling, virtual modelling in the SOLIDWORKS software environment of the GearTrax application, experiment planning, and model correction through the results of metallographic studies. The results of the study are presented as reasonable prediction criteria that consider contact cycles during the formation of fatigue stresses at the stage of defect origin. The process of the dynamic interaction of the contact worn profile of a wheel with a railway rail is explored. Polynomial equations are proposed to substantiate the optimal design and technological parameters of designing a railway carriage wheel. The permissible limits of wear of the transverse profile in the contact zone of the wheel and the ridge are justified while taking the coefficient of the reduction of contact stresses in the metal into account. The dependences of the change in static load on the utilization factor of the railway carriage load capacity are established. The dependences of changes in fatigue stresses on the design deviation of the contact area of wheel wear are established. It is confirmed that the stress concentration under cyclic loads is formed in the ferritic layers of the material structure before the appearance of wear.

The combined effect of cutting speed and feed on the power characteristics in the time of drilling

The analysis of works devoted to the study of power characteristics in the course of drilling is presented. Research results of the combined effect of cutting speed and feed on the power characteristics when drilling steel parts 45 using the experiment planning method according to plan 22 are presented. The existence of pair interaction is shown, which made it possible to assess the power of influence of one of the factors depending on the level where the other is located.

Methodical Approach to Assessing Level of the State Energy Security and Its Influence on the National Security and Economy of the Country

This paper presents possible methodical approach to assessing level of the state energy security and its influence on the national security. In order to ensure proper level of the national security of the state, it is necessary to assess dangers in a great variety of areas, particularly, in the energy sector. Authors of this paper propose a version of solving the problem with the help of application of the state-of-the-art information technologies on the basis of the intellectual analysis of statistical data. The authors provide general description of the methodical approach in order to assess dangers for the existing level of the energy security. This approach is based on the comprehensive application of the grouped expert estimates, as well as on the theory of the experiment planning (the experimental design theory) and on the group method of data handling. The proposed approach is characterised by its relative simplicity and usability from the point of view of application of the already existing software products. The results, which would be obtained with the help of this method, can be easily interpreted and analysed. In addition, this paper proposes more adequate approach to understanding level of the energy security, as well the level of the national security of the state. The paper presents the specific example for assessing level of the energy security as well as procedure for finding explicit form of the computational functional with the help of the software GMDH Shell, which makes it possible to increase validity of the derived data as compared with the known approaches. Subsequent investigations will be carried out with the purpose of development of the scientifically substantiated approach to identification of the relevant criterial values of the danger indicators in order to ensure making adequate decisions in respect of responding to these dangers

Investigation of the electrospark coating, alloying and strengthening technology

Introduction. The work objectives were the analysis and application of the technology of electrospark deposition of wear-resistant metal coatings on cutting tools or machine parts for their hardening or dimensional restoration.Materials and Methods. The technology, device and principle of operation of the modernized installation intended for electric spark application of wear-resistant metal coatings with composites T15K6, VK8 and VK6 are considered.Results. To determine the parameters of the upgraded electrospark alloying plant, experiments were carried out on hardening of polished samples made of steel 45 with hard alloy T15K6 with dimensions of 25×25×25 mm. As a result of using the experiment planning method, the possibility of selecting and adjusting the installation parameters was confirmed. The following parameters were selected for hardening samples made of steel 45 with hard alloy T15K6: current I = 1-2–A, voltage U = 40-75 V, capacitor bank capacity = 60–100 µF.Discussion and Conclusions. The use of carbon dioxide as a protective medium enables to increase the number of passes and, accordingly, the number of coating layers to twenty, to obtain a total thickness of up to 0.3 mm with a dense structure without oxides. Coatings of this thickness make it possible not only to strengthen, but also to restore the dimensions of worn machine parts. The parameters of the technological modes of electrospark alloying significantly affect the intensity of coating application and the quality of the resulting surface. A rise in the electrical parameters causes an increase in the intensity of each individual discharge and, within certain limits, contributes to an increase in the amount of the transferred coating material, as well as to deeper transformations of the coated surface in the discharge zone. Thus, an electrospark alloying plant equipped with monitoring and diagnostic tools, as well as with a protective gas supply system, can be used for hardening and restoring machine parts and cutting tools.