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The automated design issues of modular spindle heads for multi-operational metalcutting machines are considered. An option for expanding technological capabilities through the use of forming units with vertical and horizontal arrangement in the space of the machine working area is given. A 3D project for the drive of the machine's main movement with a built-in horizontal spindle head and replaceable vertical and slotting spindle heads has been developed. In the process of modelling complex drive housing parts and replaceable heads, Creo Parametric CAD functionality was developed. These functionalities with the procedure for interconnecting the three-dimensional design model and the manufactured casting mold are associated. The implementation of this procedure using the example of creating a structural element - a "Casting draft angle" in the housing part manufacturing of a slotting head is presented. The "Mechanism Design" module of the Creo Parametric CAD system models the rack-and-pinion transmission as the translationally moving link intended for processing grooves, blind-shaped surfaces, and internal cavities is used. Ways to improve the design of the rack-and-pinion gear are outlined. The main innovative idea of the rack tooth profile in the form of an arched shape is presentation. Primary analytical dependencies for a complex geometric-kinematic analysis of a rack-and-pinion transmission with arched teeth were obtained. The relationship between transmission parameters and the maximum size of the gear-cutting head has been established. A condition to guarantee the absence of secondary cutting using a gear-cutting head has been introduced. The value of the coefficient KL = 1.13 as an indicator of a decrease in bending stress and, as a consequence, an increase in the load capacity of arched teeth in comparison with straight rack and pinion teeth, all other things being equal is determined. [ABSTRACT FROM AUTHOR]

The paper considers the issue of approbation of adaptive predictive control for heating, ventilation and air conditioning systems, shows the possibility of improving the regulation processes by its application on example of ventilation system. The idea of control using predictive model is presented, the principles of control using MPC controller are noted, the controller structure and the criterion for choosing the optimal values of control signal are considered. The feature of adaptive predictive control is the presence of the mathematical model for control object, which accurately describes its behavior. The MPC controller determines the sequence of control signal values that provides the best predicted trajectory for controlled variable. The implementation of the MPC approach is shown on the example of supply VAV ventilation system of the classroom. In the considered ventilation system, the change of heat load for the room is compensated by the change of amount of supply air coming from the central supply ventilation unit at its constant temperature. To simulate ventilation system in the Simulink environment of the MATLAB application package, the block diagram was developed, and the Model Predictive Control Toolbox was used to synthesize the MPC controller. The study of transient processes in VAV ventilation system was carried out, transient process in the system without controller, with PID controller and MPC controller were compared. Comparison of the results showed that the use of the MPC controller makes it possible to improve the regulation process of thermal regime in the room by increasing the regulation quality.

This paper is devoted to obtaining a solution to the problem of parametric vibrations and dynamic stability of thin-walled underground oil pipelines, taking into account the effect of a damper. An equation has been obtained that allows estimating the dynamic stability of underground oil pipelines, which consists in constructing regions on the plane of the parameters ωmn, ω0 and the longitudinal force parameter P, as well as the internal pressure p0, where ωmn is the frequency of free vibrations, ω0 is the excitation frequency. The assessment of the dynamic stability of the oil pipeline section is made for the known values of ωmn, ω0, p0, P, k by finding a point. If the point does not fall into the outlined area, it means that dynamic stability is ensured, otherwise there is a danger of parametric resonance.

In higher eukaryotes, distance enhancer-promoter interactions are organized by topologically associated domains, tethering elements, and chromatin insulators/boundaries. While insulators/boundaries play a central role in chromosome organization, the mechanisms regulating their functions are largely unknown. In the studies reported here, we have taken advantage of the well-characterized Drosophila bithorax complex (BX-C) to study one potential mechanism for controlling boundary function. The regulatory domains of BX-C are flanked by boundaries, which block crosstalk with their neighboring domains and also support long-distance interactions between the regulatory domains and their target gene. As many lncRNAs have been found in BX-C, we asked whether readthrough transcription (RT) can impact boundary function. For this purpose, we took advantage of two BX-C boundary replacement platforms, Fab-7attP50 and F2attP, in which the Fab-7 and Fub boundaries, respectively, are deleted and replaced with an attP site. We introduced boundary elements, promoters, and polyadenylation signals arranged in different combinations and then assayed for boundary function. Our results show that RT can interfere with boundary activity. Since lncRNAs represent a significant fraction of Pol II transcripts in multicellular eukaryotes, it is therefore possible that RT may be a widely used mechanism to alter boundary function and regulation of gene expression. [ABSTRACT FROM AUTHOR]

This paper is based on the equation obtained earlier by V.G. Sokolov to find the frequencies of natural vibrations of straight sections of large-diameter pipelines. In this work, to take into account the effect of hydrostatic pressure on the pipeline wall from oil flowing at different speeds, the solution obtained by M.A. Ilgamov and A.S. Volmyr is used. At the same time, the effect of a stationary fluid flow on the pipeline wall is taken into account in the equation written in forces for the last term of the normal component of inertia forces. The resulting modified equation allows determining the frequency characteristics of the pipeline both according to the rod theory (without taking into account the deformation of the cross section) and according to the theory of shells (taking into account the deformation of the cross section).

Expression efficiency is one of the major characteristics describing genes in various modern investigations. Expression efficiency of genes is regulated at various stages: transcription, translation, posttranslational protein modification and others. In this study, a special EloE (Elongation Efficiency) web application is described. The EloE sorts the organism’s genes in a descend order on their theoretical rate of the elongation stage of translation based on the analysis of their nucleotide sequences. Obtained theoretical data have a significant correlation with available experimental data of gene expression in various organisms. In addition, the program identifies preferential codons in organism’s genes and defines distribution of potential secondary structures energy in 5´ and 3´ regions of mRNA. The EloE can be useful in preliminary estimation of translation elongation efficiency for genes for which experimental data are not available yet. Some results can be used, for instance, in other programs modeling artificial genetic structures in genetically engineered experiments. The EloE web application is available at http://www-bionet.sscc.ru:7780/EloE.

The article is about the study of the frequencies of free oscillations of a large-diameter polyethylene gas pipeline with a semi-underground installation, which carried out on the basis of the solution for a semi-underground thin-walled steel pipeline of large diameter. As a result of oscillations, the cross section of the pipeline is deformed, but it strongly depends on the geometrical and mechanical parameters set, for example, on the stiffness coefficient of the elastic medium

In higher eukaryotes, the regulation of developmental gene expression is determined by enhancers, which are often located at a large distance from the promoters they regulate. Therefore, the architecture of chromosomes and the mechanisms that determine the functional interaction between enhancers and promoters are of decisive importance in the development of organisms. Mammals and the model animal Drosophila have homologous key architectural proteins and similar mechanisms in the organization of chromosome architecture. This review describes the current progress in understanding the mechanisms of the formation and regulation of long-range interactions between enhancers and promoters at three well-studied key regulatory loci in Drosophila. [ABSTRACT FROM AUTHOR]

- The design of the main movement drive for a multioperational machine such as a machining center with a modified design of a gear gearbox is considered. A 3D modelling of the machining center drive mechanism with a portal layout was performed in the integrated computeraided design system KOMPAS-3D. Functional extended range of the C3D Modeler geometric kernel when constructing complex geometry of machine housing parts is proposed to use. The procedure for constructing gear rims with high accuracy and geometrically correct tooth surfaces in the CAD environment was applied. At the stage of forming the shape of the tooth of a multivariate choice of the tooth axial shape, it is possible to implement. A new idea to increase the efficiency of the cylindrical gear transmission of the machine speed box based on the modified tooth profile of the gears with inclined-arched teeth is put forward. An analytical apparatus for calculating the design and choosing the radius of the gear-shaping cutting head with known basic transmission parameters have been formed. A comparative analysis for the calculated values of the axial overlap coefficient in an involute helical spur gear and in a spur gear with inclined-arched teeth is carried out with the same engagement parameters, other conditions being equal. Numerical calculations for the modified version of the engagement with inclined-arched teeth compared with the involute helical gear in terms of load capacity have been shown. [ABSTRACT FROM AUTHOR]

In this paper, we solve the problem of free bending vibrations of a thin-walled gas pipeline of large diameter laid above the ground on supports. The gas pipeline is considered as a cylindrical shell subject to the action of a stationary internal working pressure, the parameter of the longitudinal compressive force. The frequencies of free oscillations and the influence of parameters on the gas pipeline are compared with different versions of the supports.

In the paper, solutions for a thin-walled bimetallic pipeline are obtained. The frequencies of free oscillations are investigated, taking into account the internal working pressure, the longitudinal compressive force, and the elastic foundation. The solutions were obtained on the basis of a geometrically nonlinear version of the semi-momentum theory of cylindrical shells of the middle bend. The proposed calculations can be used in the nuclear power industry, aviation, and petrochemical industry.

In this paper, we solve the problem of free bending vibrations of the main thin-walled large-diameter pipeline, corresponding semi-underground laying type. As a result, vibration process involves a pipeline to move the surrounding ground, which significantly affects the frequency free vibrations. The values of the natural frequencies of the pipeline will depend on the characteristics of the ground, and it’s mass. The decision takes into account the impact of the attached ground mass on the free vibration frequency based on the geometrically nonlinear version of semi-momental theory of average bending cylindrical shells.