Materials Literature
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A general methodological approach to the management of the creation and development of economic associations is considered. It is based on their representation in the form of a focused and evolving process whose driving force is the dialectical unity and struggle between the need and the opportunity, between the conce…
The generalized trajectory of the power drill (PD) operational cycle is considered. In the case under study, the PD shows the increased speed and positioning accuracy of the fluid-feed. An automated hydraulic drive for providing the structural parametric control over the operational cycle and PD positioning is offered…
The research objective is efficiency increase of the development, estimation, and improvement of quality management systems (QMS) of the machine-building enterprises. The existing classifications and operation algorithms of the QMS basic types allow optimizing the processes of product improvement, and the quality of l…
The mathematical model of training success based on the factor analysis method is presented. The psychological characteristics of the students obtained as a result of the conducted experiment are considered as factors of this method. The academic progress of students determined by the examination record is chosen as a…
The described algorithm of the business reputation valuation by the future discount cashflow (DCF) technique allows the justified investment decision-making. The technique is characterized by the computation complexity since a considerable volume of information is required for the model building. It should be noted th…
The experiments supporting theoretical conclusions on the process regularities of the vibration excitation and noise generation are considered. As part of the study, part blanks, such as thin plates and of a complex profile, were machined on the presses of T 1228 and T 1225 Models. Thus, sound levels (dBA), as well as…
According to the papers of the German and French specialists, the rail corrugation stimulates increasing the rail sound radiation intensity. Besides, the consideration of the rail corrugation actually explains the high-frequency noise spectrum. The rail corrugation is characterized by two key parameters — the corrugat…
Side shoots and plant branches unlike trunks are often not rectilinear — they can be compared with various mathematical curves. Xylem of such branches copies their curvilinearity. It motivates the spatial curvature of the chains of its tracheids and vessels. A mathematical model of water lifting and distribution cause…
Statistical spread of the electrical device parameters appears often to be a problem for their operation analysis and a precise determination of their optimum modes. Under such conditions, mathematical algorithms permitting to diagnose these devices with the accuracy sufficient for the engineer analysis are required.…
Complete information on the component reliability of the complex man-machine systems is obtained in the case of availability of the component uptime distribution laws and of their parameters, as well as of the information on the components independence. Under the violation of one of these conditions it should be assum…
A method of manufacturing involute sprocket by a standard cutter for the toothed chain is suggested. The application of involute sprockets compared with straight and standard tooth profiles has a number of advantages: noise abatement under operation, wear resistance and durability increase, etc. The selection order of…
The asymptotic solution to a problem of the hydrodynamic calculation of the radial two-layer porous bearing of infinite length with account for the permeability anisotropy of porous layers is presented. The solution is based on full nonlinear Navier — Stokes equations and Darcy's equation. The case when the porous lay…
The experimental results of noise and vibration in the section of the centrifugal treatment of the helicopter longeron tubes are given. Noise sources determining very high level increase over limitary spectra are identified. As the noise reduction up to the sanitary norms in the source itself is impossible, observing…
Some issues on forming movement modeling when drilling deep holes with the dynamic link generated under cutting are considered. The results of the spindle frequency drift trajectories simulation in Matlab according to the parameters of the servo motor and process characteristics are presented. For the first time, meta…
An effective analytical solution to an axisymmetric contact problem on the interaction between a circular plate and a double-layer elastic half-space is considered. For this, a bilateral asymptotic method is applied. The plate bends under the load and the foundation response. The solution is constructed for different…
Fatigue calculation is of primary importance when designing parts and assemblies made of composite materials to operate under the variable load. The finite element modeling of the representative bulk in the stress-strain state conforming to the operation conditions is considered. The calculation methods of polymer com…
An axisymmetric problem of the elasticity theory on torsion of an elastic half-space with inhomogeneous in depth coating of periodic structure by a non-deformable circular punch is considered. The coating is represented by a set of alternating soft and hard layers. The boundaries of the layers can be clear (piecewise-…
The phonon spectrum of cubic barium zirconate is calculated from first principles using the density functional theory. An unstable R 25 phonon mode observed in the phonon spectrum indicates an instability of the BaZrO3 structure with respect to the oxygen octahedra rotations. It is shown that the symmetry of the groun…
The doping effect of Sr and transition metals Mn, Fe, Co into the direct-gap semiconductor LaZnAsO has been investigated. Our results indicate that the single phase ZrCuSiAs-type tetragonal crystal structure is preserved in (La 1− x Sr x )(Zn 1− x TM x )AsO (TM = Mn, Fe, Co) with the doping level up to . While the sys…
The electronic structure of (Ce,Yb)CoIn5 has been studied by a combination of photoemission, x-ray absorption and bulk property measurements. Previous findings of a Ce valence near 3+ for all x and of an Yb valence near 2.3+ for x>0.3 were confirmed. One new result of this study is that the Yb valence for x<0.2 increa…