bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the probabilistic model of a fuzzy Bayesian classifier and the Gaussian mixture problem
Authors: Pevneva Anna , Pivovarova Inna
Published: December 2022

The article shows that the problem of fuzzy classification and the problem of separation of Gaussian mixtures have different theoretical solution models based on the results of the classical probability theory. A probabilistic model of the clustering and classification process based on the Bayesian approach is the joint distribution of multidimensional data points across clusters and cluster prototypes. The model is built for datasets with a normal distribution. Unknown membership values for each data point are assumed to be a random variable with some empirical distribution. The cluster prototype is also assumed to be a normally distributed random variable. The model is compared with the Gaussian mixture separation model and the main difference between them is highlighted: in the Bayesian fuzzy classification model, the product of all component probabilities is used, which means taking into account the possibility of the xn
value falling into different clusters. The computational algorithm of this model may have a wider application compared to the traditional fuzzy c-means approach, due to the lack of restrictions on clustering parameters. Some numerical results are presented that confirm the model’s operability for an artificial data set both with parameters within the traditional limitations of the c-means method and for an extended range of parameter values.
Digital processing of satellite images using neural network algorithms
Authors: Kochanov Andrey , Zolotukhin Vyacheslav , Mironenko Vladislav , Savelyeva Anastasia , Polyakova Anastasia
Published: December 2022

The article discusses the system, the basis of which can be divided into two parts, hardware and software. The hardware part is a single-board computer and software using, which includes the use of neural network algorithms. This system is able to extract the necessary information from the photo and/or video frame specified by the parameters when receiving images from the satellite. This possibility is relevant, because at the moment the trend is that large enterprises want to have at least a few small spacecraft on their account and in this regard they face a number of problems associated with limited mass and size of payload devices. Due to these certain limitations, the processing of satellite frames takes place on Earth, and not on the device itself. Image processing on the spacecraft makes it possible to send only individual fragments of data and not clog the transmission channel, which saves traffic and time. Also, it makes it possible to process data on the spacecraft itself 24/7. This becomes possible thanks to the Python programming language and the trained convolutional neural network. The neural network is connected through the free library TensorFlow. The purpose of this work is to describe the features for solving the problem of classification of objects (pattern recognition).
Calculation algorithm for non-stationary pumping of liquid foodstuffs by a centrifugal pump with an open impeller
Authors: Akhmedova N A , Levicheva O I , Naumov V A
Published: December 2022

The mathematical model of pumping liquid foodstuffs by a centrifugal pump with an open impeller was proposed in this article. The liquid levels difference in the initial and final tank changes during pumping. Therefore, the pumping process is non-stationary with a slowly changing fluid flow rate. The mathematical model includes two differential equations: the balance of the pumped liquid and the dynamics of the fluid flow in the pipeline. The operating characteristics of the centrifugal pump were approximated by second-order polynomials according to the test data of the manufacturers of this equipment. The need to take into account the influence of fluid viscosity on the pump performance is shown in the article. The pump pressure is noticeably reduced, and the power consumed increases for concentrated apple juice compared to pumping water. The system of differential equations with corresponding boundary conditions was solved numerically. The flow rate very quickly reaches a value corresponding to the difference in levels at the beginning of pumping. Therefore, the problem can be solved in a quasi-stationary approximation. The change in fluid flow over time is close to linear. Therefore, it is possible to find the pumping time of a given volume by an approximate method. The approximate calculation algorithm has been proposed. It was used to calculate the pumping of a concentrated apple juice. The effect of changes in the diameter and length of the pipeline on the performance and energy efficiency of the pumping unit has been investigated.
Parameters of contact lines of rolls
Authors: Turgunov K K , Annaev N U , Khurramov Sh I
Published: December 2022

The article defines the parameters of the contact lines of the rolls. Calculation formulas are found for determining such parameters as the ratio of strain rates in roll pairs when the deformation of the semi-finished leather product and the coating of are given by rheological models. It was revealed that the forms of contact lines in roll pairs do not depend on the methods of specifying the deformation of the leather material and the coating of the rolls.
The development of logic-probabilistic reliability model of the main electrical scheme
Authors: Kovalenko I V , Krivenko T V , Tremiasov V A , Bobrov A V
Published: December 2022

The issues of construction and analysis of the topological model in reliability analysis of main electric schemes connections in power plants and substations are considered in this article. The multi-matrix method for reliability analysis is proposed in this article for different electric schemes: two operating systems of built-up wires and one bypass system of built-up wires; two operating systems of built-up wires; one operating system of built-up wires and one bypass system of built-up wires by the obtaining multi-states. The main conclusions were made on the further direction of research.
Evaluation of the impact of measures to increase the energy efficiency of the technological process of the enterprise to the level of energy expenses in its ideal analogue
Authors: Dergachev D V , Morozov I N , Sheiko E M
Published: December 2022

The article proposes the results of assessing the impact of measures to increase the energy efficiency of the technological process to predict the ideal analogue of the enterprise. The model of an ideal analogue of an enterprise in the form of graphs asymptotically approaching the limit is considered. The conclusion gives the results of the energy saving policy and appropriate conclusions.
Prospective methods for recognizing the state of a metal-cutting tool
Authors: Tikhomirov G V , Barbashov N N , Samoilova M V
Published: December 2022

For the manufacture of high-precision parts for aviation and space technology, it is necessary to achieve high-quality work of metal-cutting machines. The accuracy of processing and the quality of the treated surface directly depends on the properties of the tool, as well as its wear. A number of devices and techniques for controlling cutting tools are known. However, many of them are not effective enough for precision machining on automated machines. For timely detection of defects and prevention of catastrophic wear of the cutting edge of the tool, recognition methods are necessary to ensure high quality control. The paper considers an algorithm for monitoring the condition of incisors, which makes it possible to increase the efficiency of active control on modern machines.
Kinematic analysis of the axle box unit operation
Authors: Mashtakov Alexander P , Khakimzyanov Rustam R , Mickiewicz Vadim G
Published: December 2022

The axle load acts on the box unit and has shock-pulse nature when the car is moving, that can lead to a mutual change in the surface positions of the roller ends with the edges of the bearing races. The ways are proposed to optimize the internal geometry of the radial and end contact elements of the roller bearing of the axle box unit. It is proposed to eliminate the occurrence of possible conditions that lead to the movement of bearing rollers into the thrust and locking of bearing rollers by increasing the minimum limit in the axle clearance of the axle box.
Application of matrices for transfer function values calculation in mechanical systems
Authors: Ershov D Y , Lukyanenko I N , Aman E E
Published: December 2022

The paper describes the formalism and methodology that can be employed for calculation of transfer function in distributed parameter elastic mechanical systems. Generalized formalism for derivation of transfer function matrices is presented as developed in accordance with the Hilbert-Schmidt theorem. Matrix-based method to determine elastic mechanical system transfer function is offered. The solution of the problem of forced harmonic oscillations of an elastic body of a mechanical system with the presence of friction is considered. The described technique can be applied to find the transfer functions of technological equipment in order to determine the dynamic characteristics of the system.
Optimization of identification of micro-objects with error control and statistical image filtering mechanisms
Authors: Jumanov Isroil I , Kholmonov Sunatillo M
Published: December 2022

Scientific and methodological foundations have been developed for the optimal identification of non-stationary objects transmitted by random time series in control systems of industrial and technological complexes, monitoring of environmental protection and ecology, palynology, medicine based on the use of statistical, dynamic, neural network models and mechanisms for extracting statistical, dynamic specific characteristics of information. The mechanisms for controlling the error in the identification of RTS, based on the use of statistical criteria - the rules of the sequential analysis, Bayesian estimation, ±3σ, confidence interval, have been investigated. The problem of control of the error in the identification of RTS by the confidence interval, the mechanisms of threshold control of the values of the random time series elements, their increments, the error of prediction by statistical, trend, dynamic models, algebraic polynomials, parabolic, cubic interpolation, extrapolation spline functions. Mechanisms for regulating the variables of the random time series identification models based on autoregressive, adaptive smoothing by R. Brown, Newton, Lagrange polynomials, orthogonal algebraic polynomials of 3, 5, 7 orders have been developed. The methodology for assessing the quality of the identification of RTS by mathematical expectation and variance and the criterion of correspondence between the relations of mathematical expectation and variance of two consecutive elements have been implemented. The experimental study was carried out according to the real data of the power grid enterprise. The effectiveness of the implemented mechanisms was studied according to the criteria of the minimum root-mean-square error, labor intensity, cost of information processing.
Reducing the impact of wind load on the operation of information-measuring and control systems of tricopters
Authors: Sleptsov V V , Ablaeva A E , Kanaev S A , Moskalenko O V
Published: December 2022

The article deals with the issues of reducing the influence of wind load on the information-measuring and control systems of tricopters. A feature of the work is the development of a general mathematical model of a tricopter, taking into account the specific characteristics of the elements: adjustable electric drives, parameter sensors (barometers, accelerometers, rangefinders, etc.). The type and parameters of the controllers of tricopter coordinate control systems are determined. A variant of reducing the influence of wind load on the information-measuring and control systems of tricopters by organizing control loops for the speeds of electric motors is considered.
A simulation model for a compounding process for commercial gasolines
Authors: Golovina E S , Khaimovich I N
Published: December 2022

Compounding commercial fuels is an important final stage of the entire production process chain in an oil refinery which defines the economic effectiveness of the company’s manufacturing activities. This paper addresses a simulation model for the compounding process for commercial gasolines. The Model is based on discrete linear programming. The target function for the optimization model is the ratio of the difference between the value of the salable product and the costs incurred by manufacturing components and electrical power to the final volume of the salable product, as well as the time it takes to prepare. The optimization model leads to the conclusion about the practicability of the in-flow blending, as well as of the necessity of selecting the right pumping equipment. The optimization model can be applied to primary calculations of economic effectiveness of the various options of organizing the process for the compounding of commercial gasolines.
Modification as a method of aircraft design
Authors: Yu Kuprikov Mikhail , Kuprikov Nikita
Published: December 2022

To optimize the expenditure of time and material resources, the Method of modifications is used. Modular design of a family of modifications allows combining complexes of components to expand the transport capabilities of aircraft, meet the requirements of air transport more accurately, maximize unification, create a range of aircraft. The modification method makes it possible to reduce time and material resources in solving aircraft design problems. And the principle of decomposition makes it possible to identify independent units and systems from which new aircraft modifications can be assembled. Models are formalized. Software and information support is developed on their basis.
Methodology for finding the virtual center of mass of the aircraft
Authors: Yu Kuprikov Mikhail , Kuprikov Nikita
Published: December 2022

There are types of aircraft for which the geometric shapes are primarily due to “hard” infrastructural constraints. The secondary nature of aerodynamic requirements makes it possible to deviate from the traditional design task. And move on to the Inverse Design Problem. A solution that allows you to reduce the number of design iterations and narrow the search for a rational solution in the Pareto-optimal area. These aircraft include vertical takeoff and landing aircraft. After analyzing the characteristics of moment-inertia units obtained after an analytical experiment, it shows that the introduction of a virtual center of mass makes it possible to reduce the radius of action of the inertial forces of the aircraft. A sequence of absolute advantages in terms of the moment of inertia of the nodes has been obtained, for example, a more optimal location of the target load, fuel tanks and power plant, which provides an advantage in the mass of the aircraft up to 7-8%, only due to the rational moment of inertia of the layout relative to the virtual center of mass. In an aircraft, the moment of inertia depends to the fifth power on the change in its linear size
The concept of using additive technologies for digital prototyping of assembly devices
Authors: Vlasov A I , Juravleva L V , Ismagilov K
Published: December 2022

The article discusses the main provisions of the concept of using additive technologies for digital prototyping of assembly devices in the production of electronic equipment. Approaches to the system design of devices and their components are formulated. General ideas about devices are generalized and systematized, types of fixtures for assembling electronic equipment are classified. A comparative analysis of the methods of classical and model-oriented (drawing-free) design is carried out. Recommendations on the use of additive technologies in the implementation of ‘trial and error’ design methods, the coordinate calculation method, wave technology, design using layout schemes and virtual assembly are given. The tasks that are solved in the process of designing and manufacturing devices in the production of electronic equipment are determined. Recommendations for modeling, simulation and prototyping of devices for testing designs and validating technological processes in order to reduce the time of technological preparation and production are given.
Arrays of combined antennas with equal-amplitude distribution of bipolar voltage pulses
Authors: Koshelev V I , Plisko V V
Published: December 2022

The paper presents the comparative characteristics of the radiation pattern of the combined antenna arrays excited by a bipolar pulse and harmonic oscillations near the central frequency of the spectrum of ultrawideband radiation. Particular attention is paid to the 3x3 array radiation source with maximum efficiency.
Solving the part identification problem using their STL models
Authors: Pechenin Vadim , Pechenina Ekaterina
Published: December 2022

The article is aimed at solving the problem of aerospace parts identification. A neural network model for part identification was developed. The proposed model consists of three modules: object detection using the YOLO3 model, preprocessing of the selected fragment, and classification of the processed fragment using the VGG19 model. A distinctive feature of the developed model is the use of STL objects for training the VGG19 neural network. To increase the reliability of the classification for each object we used photos made from three angles. The developed model has been tested on the parts of the rotor of a small gas turbine engine. The test was conducted on 100 test cases including 300 photos of parts. To train the neural network, 13,200 images were simulated using STL models. The loss function (categorical cross-entropy) for the training sample was 0.0004, and the classification accuracy was 100%. The accuracy of identification of real photos using the developed model was 97%.
Time optimization of the mixing process of concrete mix components based on unsorted gravel-sand aggregates of the initial rock
Authors: Kharkov D A , Kiseleva A D
Published: December 2022

The article proposes a new method of control and a system for regulating the uniformity of the concrete mixture in the technological process of mixing components. The theoretical substantiations of the control and regulation of the homogeneity of the mixture associated with a change in the frequency of vibrodynamic vibrations of the mixer body are given. Such technical means as vibroacoustic sensors, communication devices with the object, electropneumatic executive regulating mechanisms are selected. To determine the quality indicator of automatic control in the system, a structural block diagram with transfer functions is proposed that determine the process of operation of the ATS in a transient dynamic mode. The mixing zones of the components that determine the optimization of the uniformity of the concrete mixture in the technological cycle of the mixing process are determined.
Mathematical modeling of the laws of airborne distribution of dust particles generated in manufacturing plants
Authors: Sharibaev Nosir , Tursunov Ahror , Djuraev Sherzod
Published: December 2022

In this article was given ideas on mathematical modeling of the laws of airborne distribution of dust particles generated in primary cotton processing plants, the laws of airborne distribution of various chemically harmful dust particles, as well as the physical variables of the air environment views on the modeling of dust particle dispersion processes in the working zone, such as stability, air flow rate, numerical values of indicators
Stable control algorithms for non-stationary objects based on game methods
Authors: Igamberdiev H Z , Sotvoldiyev H I , Mamirov U F
Published: December 2022

The paper considers the issues of constructing stable control algorithms for non-stationary objects based on the concepts of game methods. According to the principle of dynamic programming, control is defined when there are or are no restrictions on control actions. A.N.Tikhonov’s regularization method is used for stable estimation of the perturbation vector using the principle of the least residual estimate, as well as the method for compiling and solving an extended regularized normal system of equations. The obtained expressions make it possible to form control algorithms for linear non-stationary objects, which are stable when the control actions are limited, taking into account the feedback channel signal. At the same time, the use of game theory methods makes it possible to optimize management decisions under the conditions of inefficiency of classical management methods under conditions of a high level of a priori uncertainty of processes in the system under consideration.
Determination of water quality from the standpoint of the trap of non-representativeness: errors that occur when combining data series
Authors: Rosental O M , Sambursky G A
Published: December 2022

The errors caused by the non-representativeness of the sample data arrays when they are directly combined are analyzed. Using examples of water quality analysis and the quality of metrological support for production processes, it is shown that even if desirable changes in controlled dependencies are observed in different data groups, changes may still be undesirable when combining these groups. It is shown that the correct unification, preserving the direction of functional dependencies, provides for the introduction of weighting coefficients in such a way that the weighted proportion of the studied ratios in the combined data arrays is the same.
Calculation of the mean restoration time, of an item based on the characteristics of the restoration process
Authors: Sadykhov G S , Kudryavtseva S S
Published: December 2022

The well-known formulas for calculating the mean restoration time (as a mathematical expectation of the restoration time of an item–after-failure operational state) assume that the characteristics of the restoration process are set on the entire time axis. This circumstance makes it difficult to use these formulas in solving engineering problems, since, on the one hand, a specific restoration process is limited by the duration of repair works, and, on the other hand, the approximation of the restoration process over an adjacent infinite period of time after the completion of the repair works is not adequate to the process as observed. Then a problem to solve is to calculate the mean restoration time of an item through the characteristics of the restoration process, knowing the ways they work for a limited period of time, the length of which is determined by (i), the duration of repair works, and (ii), their specific conditions. In this paper, such conditions are considered as some specified level of the gamma-percentile restoration time of an item, as well as the restoration rate of an item, which results from the repair works. The selected characteristics of the restoration process have turned out to be sufficient to solve the task. In this paper, the formulas are proved for calculating the indicator “mean restoration time” based on the functional manifestations of the restoration process characteristics (taking into account the specified gamma-percentile restoration level, and the restoration rate) during the repair works to restore the operational state of an item after failure. The proved formulas are valid for any law of the restorative process. The paper also provides two examples of calculating the mean restoration time. In the first example, the uniform law of the restoration process is considered for the time interval of the item being repaired after failure, and in the second example, its exponential law is under study.
Visualization technologies for hybrid training of future engineers
Authors: Belonovskaya Isabella D , Kolga Vadim V , Karaseva Margarita V , Goryainova Tatyana A
Published: December 2022

The paper is devoted to the problems of visualization technology application to train future engineers with a combination of distance learning and full-time training formats (hybrid training). The authors present directions of visualization technologies application such as prototyping of production objects, Flickr-illustration of presentations, animation and video laboratory work. The visualization technologies demonstrate a positive impact on the professional and personal success of future engineers.
Investigation of the influence of the flow velocity of the measured liquid on the oscillation frequency of the resonator of a vibration-frequency density meter for the chemical industry
Authors: Huseynov T K , Abdulova N A , Abdullayeva S C , Shirinova A Y , Hashimova A R
Published: December 2022

The article is devoted to the study of the influence of the flow velocity of the measured pity on the readings of the vibration-frequency density meter. For this purpose, the process of free proper transverse vibrations of a resonator made in the form of a homogeneous tube rigidly fixed at the ends, along which the fluid flow is organized, is investigated. A differential equation of the resonator’s own transverse oscillations is compiled, taking into account the elastic forces, inertia forces and friction forces acting on the resonator. At the same time, the Coriolis force is neglected, in view of the rigid fastening of the ends of the tube. Taking into account the fact that the resonator oscillations are supported by the self-oscillation system, the friction force is compensated by an external force and in the differential equation the friction force becomes zero. As a result of solving the differential equation, the dependence of the frequency of self-oscillations of the resonator on the flow velocity of the measured liquid is determined. Possible ways to reduce the influence of the fluid flow velocity are determined. The conclusion is made about the expediency of determining the limit value of the fluid flow rate when determining the operating conditions of the density meter.
Investigation of stress-strain state of pipeline hoist taking into account installation displacements
Authors: Kulakov P A , Rubtsov A V , Abushakhmin A A , Yakubova P R , Greb A V
Published: December 2022

Stress-deformed state of a technological equipment at oil and gas refinery facilities has an ambiguous character and may depend on such factors as, for instance, operating conditions, design feature, material degradation rate, different deviations during assembly and installation etc. Moreover, the maximum level of working stress can be changed either according to linear or nonlinear laws depending on operating machinery and determining parameter of technical condition. This aspect is highly important at forecasting the further safe operation. In a modern world it is very important and urgent to build up equipment model and its parts which are digital analogue of a real facility. Application of such digital models allows to forecast future behavior of facility at the present and for the future depending on change rate of specific parameters, to determine positive and negative schemes from high stress formation point of view in the structure. Such digital model can be applied on each stage of an equipment service life and make forecasts of an equipment transfer to critical state, to determine possible reasons of changes and to carry out prevention activities. This article considers the stress-deformed state of a technological pipe operated under vacuum at different locations of its fixation on nozzle pipes of technological apparatuses.
Simulation of graphs of physical effects for information and energy circuits
Authors: Litvinov Y , Bushuev A , Nuyya O
Published: December 2022

A structural mathematical model of physical effects in the form of a weighted graph is considered. The basis for classifying the database and creating trends of physical effects is the concept of invariant. The transfer matrix based on the dimensions of the input and output of the effect is an invariant. A dimensional simulation of multidimensional physical effects is considered and a numerical estimation of the obtained models is proposed. The estimation is used to synthesize the operating physical principle of information and energy circuits.
Dynamic speckle imaging with SVD compression
Authors: Stoykova E. , Levchenko M. , Ivanov B. , Madjarova V. , Nazarova D. , Nedelchev L. , Machikhin A. , Park J.
Published: December 2022

Dynamic speckle imaging (DSI) of areas with different speed of processes ongoing in industrial or biological objects relies on statistical processing of a large number of images of the speckle patterns formed on the objects surface under laser illumination. The DSI visualizes the speed spatial distribution as an activity map. We propose compression of the raw DSI data by applying singular value decomposition (SVD). A specific feature of speckle images for DSI is lack of a structure with areas of close intensity values. The gain from the direct SVD application may be modest in cases when a great number of non-zero singular values is needed to build an activity map comparable in quality to the ground truth map from bitmap images. For higher compression, we propose SVD to be applied to the 2D arrays containing the differences between the successive images. The SVD compression has been verified by using synthetic and experimental data.
Modelling of diffraction of X-rays in perovskite superlattices
Authors: Kokosza Ł , Mitura Z
Published: December 2022

Nowadays, different perovskite structures are widely investigated because they can be potentially used in many branches of industry. If two materials are deposited alternately on a substrate, then a superlattice having some unique properties can be formed. However, X-ray intensity distributions for perovskite superlattices, especially for very thin films, are difficult to be computationally determined, because many different parameters need to be considered to reproduce a superstructure of a sample. The main purpose of this work is to demonstrate how basic intensity distributions can be generated for perovskites, XRD technique and how to improve results using specific numerical methods. The computer application with a user-friendly graphical interface has been developed employing Unity software (with 3D graphics tools) and Oracle Database (through Oracle Cloud Infrastructure). The calculations are based on the kinematical theory of diffraction. The values of some important parameters and the results are stored in the assigned database. It is assumed that epitaxial superlattices can be prepared on substrates using molecular beam epitaxy or pulsed laser deposition methods. The desktop application allows for designing samples of different thicknesses and combinations of monolayers. The results are more realistic if Monte Carlo simulations are done although longer computation time is required. The software developed should be helpful to compare in detail virtual model results with experimental data.
Bending crashworthiness of bionic thin-walled structures inspired by sugar cane stalks
Authors: Estrada Q , Reynoso E , Szwedowicz D , Rodriguez-Mendez A , Coutiño E , Mora T De la , Wiebe L , Silva J , Torres C
Published: December 2022

Recently, the design of biologically inspired thin-walled structures has been increasingly popular due to the successful adaptation of biological organisms to their environments due to millions of years of evolution. Plants with high bending resistance to counter the effect of wind forces on slender and tall stalks can be found in nature. To this end, this paper investigates the bending crashworthiness of mechanical structures inspired by sugar cane (Saccharum officinarum). The biological patterns of sugar cane were obtained with a Scanning Electron Microscope, and five bionic thin-walled structures (BTWS) were considered. In all cases, the structures were modeled with 6063-T5 aluminum and numerically evaluated using the finite element method using a three-point bending test. The effects of cross-section configuration on the crashworthiness performance of the structure were investigated. Our results show a better version of the BTWSs relative to a typical circular profile. An increase in energy absorption from 15.60% to 40.27% was computed. The best CFE performance was obtained for a structure defined by a central octagon surrounded by smaller trapeziums. Such a structure is therefore highly recommended for bending crashworthiness applications.
Modeling of a transient low-temperature waste heat recovery in the plate heat exchanger in Flownex Simulation Environment
Authors: Zolińska K , Mirek P , Panowski M
Published: December 2022

The paper analyses the feasibility of determining the parameters of a heat exchanger operating in the crop production and realising low-temperature heat recovery from biological processes. For the first time, the Flownex 8.7 Simulation Environment has been used for this purpose. The temperature of the waste water was between 20 and 30°C. On the basis of the simulations, the power of the heat exchanger is determined to be 1 MW. The heat exchanger can efficiently heat up cold water from a deep well (7-10°C) to an assumed temperature of 19.7°C. The results from the simulation calculations correspond to the results obtained under actual conditions within a range of up to 2%.
Application of artificial neural networks model to predict the levels of sulfur dioxides in the air of Zamość, Poland
Authors: Kujawska J , Kulisz M , Aubakirova Z
Published: December 2022

Air quality control and its prediction are particularly important for human health and life. Sulfur dioxide constitutes one of the air pollutants that play an important role in air quality pollution. An artificial neural network model was employed to forecast the levels of sulfur dioxide in the air of Zamość (Poland). The measured data of the meteorological station of Zamość in 2017-2019 were used for the model. Temperature (T), relative humidity (RH), wind speed (WS), wind direction (WD), SO2, PM10, NO2, NOx, CO, O3, C6H6 were used as input parameters for building the neural network model. Regression value (R) and Mean Squared Error (MSE) were used to estimation the model. The results show that neural network is capable of predicting the sulfur dioxide levels in the air.
Advances in analysis, quantification and modelling of N2O emission in SBRs under various DO set points
Authors: Shourjeh M S , Mehrani M J , Kowal P , Szeląg B , Drewnowski J
Published: December 2022

Nitrous oxide (N2O), considered a major greenhouse gas (GHG) in wastewater treatment plants (WWTPs), is produced during both nitrification and denitrification processes; hence, it needs to be controlled by internal and external strategies. Various factors, such as DO, temperature, and pH, could be incorporated into the mitigation of emissions in WWTPs. In this research, potential operational strategies were investigated in order to find the optimal range for DO and temperature for controlling the N2O production during the nitrification process. In parallel, the activity of nitrite oxidizing bacteria (NOB) could also be limited under optimal conditions to make the process more cost-effective and energy-saving. In this regard, under a lab-scale environment, DO = 0.7 mg/l was detected as the optimal range for inhibiting NOB activity and maintaining AOB activity. Moreover, the importance of developing mathematical modelling methods has gained significant attention in order to better understand the possibility of minimizing GHG in WWTPs. In this study, advanced mathematical modelling methods were used for simulating the kinetics of the nitrification process to determine the interaction among different operating factors compared to nitrification rates.
Subharmonic responses of a nonlinear energy harvester with an asymmetric double well potential
Authors: Litak Grzegorz , Margielewicz Jerzy , Gaska Damian , Caban Jacek , Wolszczak Piotr , Ma Xiaoqing , Zhou Shengxi
Published: December 2022

A nonlinear energy harvester with asymmetric potential wells is studied numerically. An energy transducing piezoelectric patch is attached to the cantilever elastic beam to harvest kinetic energy of the moving frame. To obtain an asymmetric effect in the double well potential induced by permanent magnets, an elastic ferromagnetic beam resonator misaligned with respect to the magnets' distribution axis of symmetry was used. The system response under the frequency-swept excitation reporting bifurcations to subharmonic and chaotic solutions was analysed. The sensitivity of the system solutions to the parameters responsible for potential asymmetry and electro-mechanical coupling was also investigated.
Crystallization of Aluminum droplet at low undercooling: homogeneous nucleation approach
Authors: Kožíšek Z , Král R , Zemenová P
Published: December 2022

Crystallization in an undercooled Aluminum (Al) droplet occurs via the formation of crystalline nuclei by homogeneous or heterogeneous nucleation and successive growth of nuclei. Clusters of a new phase appear in the system due to fluctuations and after reaching a critical size grow up to microscopic size. Crystallization event at low undercooling 6.4°C of 9.91 mg in compact Al sample was detected using isothermal differential scanning calorimetry (DSC) after several tenths of minutes. In this case, standard analysis based on Johnson-Mehl-Avrami-Kolmogorov (JMAK) model is not appropriate as Avrami parameter n obtained by fitting of DSC data is too low (n ≤ 1 and thus the dimensionality of the system d = n – 1 ≤ 0). Al growth rate is extremely high and that is why we presume that the time delay of crystallization, detected by DSC, is slightly higher than nucleation time delay. A homogeneous nucleation model is applied to determine the basic characteristics of nucleation: the size distribution of nuclei, nucleation rate, total number of nuclei and crystallization fraction at the nucleation process. The number of atoms in a liquid Aluminum droplet decreases with time as the formation of a new crystalline phase occurs. As a consequence, a decrease in stationary nucleation occurs. It is shown that decrease in the number of atoms in a liquid Al droplet is predominantly caused by formation of subcritical clusters.
Design of welding parameters for laser welding of thick-walled structures made of aluminum alloy
Authors: Babalová E , Ďuriš R , Behúlová M
Published: December 2022

The paper deals with the laser welding of thick-walled plates with a thickness of 20 mm made of EN AW5083-H111 aluminum alloy. A simulation model for the analysis of the laser welding process is developed and verify using temperature measurement during experimental laser welding of samples by a TruDisk 4002 laser device. Based on the numerical simulation of the laser welding process in the ANSYS program code, suitable parameters for production of high-quality weld joints were suggested. For welding at a speed of 10 mm.s−1, the laser power of 7 kW is recommended. A laser with the power of 10 kW is required for the higher welding speed of 20 mm.s−1.
Charge traps in Zn- and Mo-based oxide microstructures. The role of Mo
Authors: Buryi M , Ridzoňová K , Artemenko A , Děcká K , Landová L , Remeš Z , Mičová J
Published: December 2022

Peculiarities of the point defects creation under the X-ray irradiation and the influence of Mo doping in ZnO: Mo (10 and 30%) and MoO3 micro-powders fabricated by the hydrothermal growth method were studied in detail. It has been found that some new phases other than ZnO are created upon the heavy molybdenum doping. They were tentatively ascribed to complex zinc molybdates existing in the form of platelet flakes. The MoO3 sample contained both hydrated and anhydrous MoO3 phases in the form of microneedles. The molybdenum charge state was Mo6+ before X-ray irradiation in all the materials. X-ray irradiation resulted in creation of molybdenum- and oxygen-based charge trapping centres, i.e., Mo5+ and O− or

O
2
−

. Part of them is expected to exist in the pure ZnO and MoO3 phases whereas the rest appears in the complex zinc molybdates.
The analysis of surface roughness of the samples produced by 3D printing
Authors: Oravcová J , Labašová E
Published: December 2022

This paper deals with measurement and analysis of surface roughness of samples produced by 3D printing, Gembird white and Verbatim white. Process parameters such as print speed, print layer thickness, and print material changed when the samples were printed. The surface roughness of the samples was measured using the TR200 roughness meter. The paper analyzes the roughness parameter Ra, which represents the mean arithmetic deviation of the profile.
Modification of Glass/Epoxy laminates using micro/nano particles from carbon wastes
Authors: Tomková B , Pechočiaková M , Novotná J
Published: December 2022

This study is focused on the influence of a modified matrix on glass fiber reinforced laminates, which inherently have different material properties than carbon fiber composites. For this study we modified the green epoxy resin with 2.5wt% of carbon based fillers (synthesized graphene nanopellets, and milled recycled carbon fibres), which were subsequently applied to the glass multifilaments, and vacuum cured to obtain fiber/epoxy UD laminates. The prepared samples were further tested on the mechanical, thermo-mechanical and electrical properties, to evaluate the filler influence on the studied type of glass/epoxy laminates. Aim of this work is to study the influence of carbon fillers on overall composite properties, and evaluate its applicability for the improvement of UD glass epoxy laminates without having to significantly change the weight of component and the technology of the composite production.
Evaluation of Heat Flux Distribution Characteristics of a Concentrated Solar Dish Collector with different geometric indices
Authors: Shanmugam Mathiyazhagan , Maganti Lakshmi Sirisha
Published: December 2022

The concentrated solar dish collector is a promising technology for generating both electricity and thermal energy together and it is termed as concentrated photovoltaic thermal. The important component of the parabolic dish collector is the absorber; where all concentrated lights are falling. The present paper has investigated the heat flux distribution characteristics of the flat plate absorber based solar dish collector by using the ray-tracing simulations. In concentrating dish collector, rim angle and dish diameter are significant factor of the flux distributions. The present study reported the average heat flux distribution, maximum flux intensity and non-uniformity of flux distribution for different geometrical conditions. The maximum heat flux rate attains the rim angle between 35 to 55° for any dish diameter. Where the peak flux intensity raises concerning raises of rim angle and peak flux occurred at rim angle 90°. The increase of heat flux intensity causes the non-uniformity of heat flux distribution over the absorber surface. The non-uniformity factor is mainly influenced by the rim angle, not a dish diameter. When rim angle 15 & 75°, the non-uniformity is 2.5 & 10 respectively for whichever dish diameters. A critical rim angle produces the non-uniformity factor. Results shows that optimization of rim angle is a significant contribution for decreasing the non-uniformity index of concentrator; it most valuable for coupled thermal and electricity generating applications.
Thermal performance analysis of PCM building for Moderate climatic region in Bangalore City, India
Authors: Kumar S. , Sheeja R. , Ajin M. , Chandrasekar P. , Sekar S. , Sai Krishnan G.S
Published: December 2022

A major percentage of the energy is utilised for the building sectors for cooling the building which is used for Airconditioning systems. One of the techniques for decreasing energy consumption in building systems is passive cooling. The PCM materials was integrated in the building which is isothermal temperature for storing and retrieving the energy during a phase change. The stored PCM is a constant temperature for phase change and also gives the large potential of energy during the storing and releasing energy. The integrated building wall to prevent the solar heat infiltration into buildings and controlling the indoor temperature swing. The selection and efficiency of PCMs are highly subjective to climatic conditions where they applied. In the present study, a real time PCM integrated residential building is studied through numerical simulation using Design Builder software in moderate climatic condition in Bangalore city, India. The result shows that throughout the year, the PCM room does not required any air-conditioning device for cooling application.
Design and Mathematical Modelling of Proton Exchange Membrane Fuel Cell used in Automobiles
Authors: Micha Premkumar T , Shantha Rubia K Lindsay
Published: December 2022

The demand for electric vehicles is increasing day-by-day, considering a noise-free, pollution-free, and cost-efficient vehicle. But the fact that Electric Vehicles (EVs) cause less pollution than traditional IC-Engine Vehicles is not completely true, as switching to an electric vehicle produces an equal amount of pollution as in an IC-Engine vehicle. Charging an electric vehicle involves electrical energy from conventional thermal power plants, and Lithium-ion extraction and disposal pollute the air and land, respectively. The Electric Vehicle also has a lower driving range in comparison to the IC-Engine vehicles. Therefore, an alternative for both Electric and IC Engine vehicles that can significantly reduce environmental pollution and provide a better driving range is the need of the hour. Proton Exchange Membrane Fuel Cells or Polymer Electrolyte Membrane Fuel Cells (PEMFCs) will be an ideal solution to increase the driving range of the vehicle and reduce pollution. These fuel cells require hydrogen gas in a compressed state and oxygen from the atmosphere. The main objective of the research is to design and develop a PEM Fuel cell that can be used to achieve zero-emissions in automobiles. In this work, a mathematical model in MATLAB Simulink is used to simulate and test the PEM Fuel cell. The cell parameters, such as stack voltage and current density, are analyzed for various pressures, temperatures and humidification at the anode and cathode. It is observed that the model demonstrated the effect of reducing the relative humidity in both anode and cathode and results in the membrane became dry and highly resistive. So, at higher current density, more voltage drops in the fuel cell stack.
Recent Developments in Design and Operations of Solar dryer.
Authors: Harini S , Kavya V S , Ramana A S
Published: December 2022

Solar drying is useful in several residential, commercial and industrial applications. Proper dryer design, operation and maintenance are essential for enhancing the dryer performance and better quality of the dried product. Solar dryer is beneficial as it protects the product from adverse climatic conditions and quickly economically dry the product. The dryer design has undergone significant shapes, dimensions, and storage features leading to better reliability. Researchers worldwide have reported higher energetic and exergetic performance through advanced design, measurement, and control features. Conventional dryer’s efficiency deterioration is attributed to the lack of proper material selection and computational fluid flow techniques. Traditional dryer designs have focused on product drying rate while advanced sustainable solar dryer designs increased solar thermal utilization in a limited area with locally available materials based on fluid flow conditions suitable to the microclimatic conditions. Analysis using computational fluid dynamics (CFD) software has assisted in refining dryer designs to be compact with the complex flow and quick product drying features. The present paper tracks developments in solar dryer designs for different dryer classifications. Recommendations for energy-efficient design and measures for improvement in existing dryers are also discussed.