A technique for constructing a digital filter based on the discrete Fourier transform as part of microprocessor protections for electrical installations which is characterized by increased performance in the transient mode of setting its output signal is considered. To implement the filter, it is proposed to use the so-called equivalent orthogonal components of the input current or voltage signal which are a function of the current value of the nonlinear correction factor and the orthogonal components of the fundamental frequency signal isolated using a digital Fourier filter. The rate of change of equivalent orthogonal components in transient modes is determined by the nature of the change in the nonlinear correction factor. To form the latter, it is necessary to have two independent transition characteristics of the input signal. Previously, it was proposed to generate these characteristics using two digital filters, viz. the actual Fourier filter which extracts the actual value of the fundamental harmonic from the input signal and the additional filter which determines the actual value of the entire input signal. In this article, it is proposed to abandon the additional digital filter and determine the nonlinear correction factor, as well as the orthogonal components of the equivalent signal using a direct digital Fourier filter. A mathematical model of the developed filter and element models for reproducing test influences are implemented in the MATLAB-Simulink dynamic simulation environment. The operation of the digital Fourier filter model with accelerated operation in transient mode was tested using several types of test influences, viz. a sinusoidal signal with a frequency of 50 Hz, a signal with an aperiodic component, an influence with higher harmonics, as well as a signal close to the real secondary current of a short circuit current transformer. The computational experiments that had been conducted revealed a significant (up to 1.5–1.7 times) increase in the speed in the transient mode of the proposed digital filter compared to the standard Fourier filter.  

Electric currents arising in metal-semiconductor contact are represented as the sum of diffusion currents and drift currents. The use of various empirical formulas was proposed to determine their value. This approach to determining electric currents in metal-semiconductor diodes does not allow pinpointing experimentally obtained values of electric currents. In this regard, there was a problem in developing the theoretical foundations for the production of this type of equipment on a sufficiently sound theoretical basis, taking into account the latest achievements in electrical engineering and electronics. The theoretically calculated surface of triatomic molecules for silicon completely coincided with the experimental data obtained on a tunneling microscope. The process of applying a film made of germanium or silicon semiconductor to an aluminum metal base is considered. It is shown that the most optimal is the application of coatings by laser spraying. The concentration of free electrons in the conduction band of aluminum is determined, which occurs due to the ionization of negative ions and thermoautoelectronic emission of electrons from the metal under the influence of temperature and applied external voltage. A theory of the formation of electric currents of conduction and displacement has been developed. The conditions for the occurrence of an electric conduction current in columnar cavities on the aluminum surface and displacement currents in the supply wires are specified. It is shown how the conversion of conduction currents into a displacement current occurs at the boundary of the p–n junction.  

Corrosion of various gas pipelines,especially such widespreadtype of it aselectrochemical ones,isthemainthreattosteelundergroundpipelines during the operational phase. The negativeeffect of corrosionisthedirectloss of metal,increasedmaterialandlaborcostsformaintenance,repairandreplacement of pipelines,equipmentdowntime,deterioration of safetyandenvironmentalsituationincase of release of the pumpedproduct(especiallyifit is combustiblegasoroilandpetroleum products)into the environment.Thearticleprovides an analysis of the complex of soil-and-soilfactorsaffectingtheintensity of corrosionprocessesoccurringonundergroundsteelpipelines, and highlightscurrentresearchapproachestothisissue as well asdomesticandforeign relevant literature sources. Thekeyparametersdetermining the corrosiveaggressiveness of the soil,suchashumidity,soil aeration,its physical-and-mechanical properties, the chemicalcomposition of the soilelectrolyte(including the content of chloridesandsulfates), the presence of a number of specificsoilmicroorganisms, areconsidered. The possibility and expediency of using the computer simulation method to assess their impact using modern software tools, in particular, the SOLID and ANSYS software environments, as well as neural network modeling technologies, are considered and demonstrated. Computer simulation provides ample opportunities for analyzing and predicting corrosion processes depending on changes in environmental conditions, which can be of great practical importance for a better understanding of these processes and their impact on the reliability and durability of steel underground pipelines inthesespecificconditions.

The article is devoted to the development of new methods for processing experimental data for drying processes based on the dependence of dimensionless temperature on generalized complex variables characterizing the most general patterns of drying in the period of its rate decreasing. The generalized drying time, the ratio of drying time over drying periods, and the ratio of the current moisture content to the critical one are used as generalized complex variables. The dimensionless temperature complex represents the relationship between the ratio of the temperature difference in the period of rate decreasing and the temperature difference in the period of constant rate. A method for determining the average temperature from the solution of an unsteady heat equation for thin flat bodies based on the Predvoditelev and Fourier criteria is considered. For the case of heating a thin flat body at a constant ambient temperature, a method for calculating the average temperature using the heating rate of a wet body is given based on the heat balance equation for the second drying period. The methods for determining the average temperature for the period of decreasing drying rate are presented; they are based on complex variables, viz. generalized drying time and the ratio of drying time by period. Processing the experiment using a dimensionless temperature complex makes it possible to determine the average temperature of the material, taking into account the influence of important characteristics of drying kinetics on the process. The processing of the experiment based on the temperature coefficient of drying using experimental temperature curves is presented. The obtained formulas are checked to establish the accuracy of the calculated temperature values from the experimental temperature curve. A comparison of the obtained calculated temperature values with the experiment is given in the tables for all the materials under study.

The article briefly considers the current state and prospects for the development of biogas (biomethane) production technologies during organic waste recycling. The relevance of the problem is determined by the fact that the experience of operating biogas complexes in the conditions of the Republic of Belarus during biogas generation only from organic waste has shown low economic efficiency. Atthesametime, solving the importanttaskofrecyclingindustrialandhouseholdwaste while simultaneouslyobtaining an energyresourceandorganicfertilizerisnotonlynecessary,butalso an attractiveresult from boththeenvironmentalandenergy production points. The state of this problem abroad shows the presence of potential for the development of biotechnology in our country both in the technological and in the system-constructive design of biogas complexes. The implementation of this potential in practice presupposes that the developers have an adequate mathematical apparatus describing the transfer processes in bioreactors. An analytical solution of the mathematical model of the organic waste fermentation process is given, which is supposed to be used to study the transfer processes in flow-type biotanks when designing hybrid energy-technological systems for biogas generation using alternative energy sources. It is shownthat the mathematicalmodelobtained as aresult of the analyticalreviewfor the studyis in goodagreementwith the empirical data obtainedtodescribe the continuousoperationof a flow-through bioreactor,andisingoodagreementwith the results of numericalcalculationsofanalyticalmodels by anumber of otherresearchers. Thisanalyticalsolution makes it possible to determine the characteristicdependences of the biogasproductionrate, the dynamics of itsgenerationrate,changes in the concentration of nutrientabsorbed by bacteria,and the concentration of bacteriain a flow-typebioreactordependingon the rate of nutrientsupply to thebioreactor. The obtainedsolutionsareexpected to be usedin the synthesis of controlalgorithms for the developed multi-resourcehybridenergy technology systemforgeneratingandenrichingbiogas of a flow-storagetypeusingalternativeenergysources.

The purpose of thisstudyis to estimate the costsofincreasing electricity consumptionin the Republic of Belarus for thelongtermin the context of the development of nuclearenergy. The initial data on various activities in the industrial sector (productivity, capital expenditures, increase in electricity consumption) were prepared based on the analysis of investment projects planned for implementation in the Republic of Belarus and foreign countries (mainly the Russian Federation). Toachieve this goal, an optimizationmodelwasbuilt. The optimizationcriterionis the minimization of capitalexpenditures for theimplementation of measurestoincrease electricity consumption while achieving its technicallypossiblepotential. The limitationswerethetechnicallypossiblepotential for increasing electricity consumption,aswell as the volumeofoutput. Based ontheoptimizationmodel, taking into accountvariations in inputparameters, scenarios have been developed that provide for an escalatingincrease in the volumeofproductsproduced in order to minimize the totalcostsofimplementing a set of measures. The simulationresultsshowedthat in order toincrease electricity consumptionfor a number of types of economicactivitiesin the industrialsector, the production of a particularcategory of productsmust be significantlyincreased.Thiscan, on theonehand,act as an instrument of import substitution(i.e., refusalofimportsupplies of thiscategory of products)and, on theotherhand,increase the exportpotential of industrialproducers of the Republic of Belarus.