Development of Enterprise Management Tools Radio-electronic Industry in Their Conditions Diversifications

The article presents the results of the research, the relevance of which is determined by the urgent need to improve the management tools of enterprises of the radio–electronic industry at the present time. The subject of the study is this tool used in the conditions of incomplete initial data and uncertainty of the external environment of enterprises due to changes in their production and economic activities during the period of production diversification. Some models describing the analyzed process taking into account its specifics are considered, which allow obtaining probabilistic–time estimates of the development of enterprises in the studied conditions. For this purpose, we used methods that take into account the vibrational component in the analyzed time series, as well as expert methods. The application of the proposed algorithms in practice helps to optimize diversification measures, accelerate the innovative development of radio–electronic industry enterprises and increase its efficiency.

The application of the cyclic coherence for distributed planet fault detection in planetary gears

The vibration-based condition monitoring of planetary gears is a highly active and challenging field of research. Many signal processing techniques have been proposed, with the aim of promoting the fault component in the signal and, consequently, highlighting the fault signature (ie the damage symptom). Most of these techniques consider the fault contribution as being deterministic, which is true in the case of an advanced and localised fault. Such techniques may fail in other scenarios in which, for instance, the fault is of a distributed nature and its vibrational component is weak. In such a case, the fault component is likely to be randomised and turns cyclostationary. The present paper suggests the presence of an additional cyclostationary component in planetary gear vibrations. The presence of this component is explained by the presence of load fluctuations at the meshing points and the random micro-irregularity in the stiffness of gear components, as well as the presence of distributed faults. A simplified signal model is proposed to explain the vibration signal structure of healthy and faulty planetary gears (with a planet fault in the case of the faulty gear). Also, a cyclostationary-based condition monitoring approach is proposed, based on the cyclic coherence. The proposed approach is validated on real-world vibration signals acquired from a planetary gear benchmark.

On the specific heat of compounds with spinel structure - I. The ferrites

The representation of the lattice vibrational component of the specific heat first proposed for MgAl 2 O 4 is applied to cobalt and nickel ferrite. In each case, subtraction of the theoretically predicted lattice specific heat from the experimental data yields a residual contribution which closely follows a T 3/2 law. Good quantitative agreement with values derived from Kaplan’s theory of spin-wave dispersion may be achieved in the temperature range 180–300 K and at liquid-helium temperatures, by assuming an exchange energy J AB = 2.28 x 10 -3 and 2.84 x 10 -3 eV for CoFe 2 O 4 and NiFe 2 O 4 respectively. At intermediate temperatures, however, the analysis is complicated by additional effects associated with relaxation of acoustic lattice modes.

On the specific heat of compounds with spinel structure - II. Zinc ferrite, a paramagnetic compound with magnetic ion occupying the octahedral site

The representation of the lattice vibrational component of the specific heat for compounds with cubic spinel structure used in part I is applied to the paramagnetic substance ZnFe 2 O 4 Analysis of the experimental data over the temperature range 10–350 K reveals a magnetic contribution in the neighbourhood of the Néel point in reasonable agreement with the theoretical calculations of Tachiki & Yosida (1957) and an anomaly at 75 K which is attributed to transitions by the Fe 3+ ion between the two equivalent potential minima within the octahedral site. Further analysis of the tail of this anomaly, which varies inversely as the square of the temperature for almost 90 K, leads to an estimated height for the potential barrier of 14.8 ± 0.5 x 10 -3 eV.