bluuebunny/crossref_metadata_2025 huggingface dataset:
Wireless strain synchronization acquisition method based on Kalman Filter
Authors: Tang Yu , Dai Yawen
Published: February 2021

For distributed wireless sensor networks, the time synchronization mechanism is the core part and the key to realize the coordination and processing of tasks between nodes. In this paper, an algorithm based on kalman filter is developed the wireless strain of synchronous acquisition system, through the coordinator fixed time interval by a synchronous message, when each node receives the synchronous message to mark its timer timestamp clock information of nodes, then the node according to the records of the clock information periodically call kalman filtering algorithm is used to estimate the next cycle of its own real clock and standard clock deviation coordinator, in the next cycle, real-time compensation is made by adjusting the overflow count value of node timer to achieve high synchronization accuracy. The sensor nodes in the system have high strain sampling accuracy and meet the requirements of general engineering applications.
Research on Model Predictive Control Based on Sensorless Permanent Magnet Synchronous Motor
Authors: Fan Shengwen , Zhang Xinsen , Tong Chaonan
Published: February 2021

For permanent magnet synchronous motor (PMSM) speed control system, aiming at the problems of slow dynamic response and large dependence on system model parameters of traditional PI control of PMSM, the model predictive current control strategy is adopted to design the predictive model. Aiming at the problems of poor reliability and high cost of traditional permanent magnet synchronous motor with mechanical sensor, the speed sensorless control technology is introduced to design the control structure, and the rotor position and speed are estimated by sliding mode observer method. Through simulation verification, the results show that the combination of the above two control methods can obviously improve the performance of the traditional permanent magnet synchronous motor control system, and has strong robustness under the conditions of motor parameters and load changes.
Improved two-vector model predictive torque control for PMSM
Authors: Sun Chaojun , Liu Shuxi , chen Lan
Published: February 2021

Aiming at the problems of the traditional model predictive control (MPTC) of permanent magnet synchronous motor (PMSM) that the weight coefficient setting is cumbersome and the torque and flux pulsation are large, an improved PMSM two-vector model is proposed to predict the torque. This method expands the virtual vector to increase the voltage candidate vector, combines the voltage vector to act on the torque and flux linkage principle, selects the voltage vector, and reduces the calculation amount of the candidate vector. The evaluation mechanism of the selected vector is set by combined with the duty cycle method, so the weight factor of cost function in the traditional method is eliminated. The simulation results show that the improved method proposed can not only maintain high dynamic performance, but also improve the control effect of torque and flux linkage in the steady state of the system.
The power-delay product and its implication to CMOS Inverter
Authors: Han Zitong
Published: February 2021

Due to power dissipation has always been a significant standard for low power VLSI design, as a parameter that could reflect both circuit power consumption and delay, Power-Delay Product is of great research value. This paper mainly explores the working principle of CMOS inverter, and the definition, and formation causes of PDP. Two experiments were designed based on LTspice for investigating the effect of width to length ratio of the channel of transistors and the stack approach on the propagation delay and dynamic dissipation of CMOS inverter. It is verified that the propagation delay of the inverter is just related to the ratio of the width of the channel between NMOS and PMOS transistors. It is also verified that the range of ratios of the width of the channel between two transistors which makes the propagation delay and PDP minimum is 2∼4, and the stack approach could reduce the PDP in the CMOS inverter effectively.
Construction and Application Research of Knowledge Graph in Spacecraft Launch
Authors: Chao Kou , Tao Liu , Li Ma , Guoyu Jiang , yuchao Wang , Yu Zhao
Published: February 2021

In this paper, through analyzing the necessity of constructing a knowledge graph in spacecraft launch, we construct and use a knowledge graph in spacecraft launch, which serves as not only an effective way of solving the problem of "sparse knowledge" and "incomplete knowledge" in a sea of data but also a basis for achieving Semantic Artificial Intelligence (Semantic AI) and complex data analytics and applications. On the basis of understanding the basic technical architecture of knowledge graph, this paper analyzes the construction approaches of the knowledge graph in spacecraft launch in terms of knowledge source, modeling, extraction, fusion, inference, and storage. By means of the knowledge graph, automatic question-answering based on semantic search, fault detection based on machine learning, and portraits of equipment or information system can be achieved at the launch site. In doing so, the intelligent data engineering and construction at the launch site can be improved.
Research on sales Forecast based on XGBoost-LSTM algorithm Model
Authors: Wei He , Zeng QingTao
Published: February 2021

Reasonable sales forecast is very important for enterprises. The short-term and long-term sales changes of a product are helpful for enterprises to make marketing strategies and sales decisions. On the basis of in-depth analysis of the characteristics of a certain algorithm model and long and short memory neural network, and according to the data set provided by a supermarket chain in kaggle competition, a XGBoost-LSTM neural network combination model for sales forecasting and a classical time series prediction model are constructed to compare the experimental results. The experimental results show that the XGBoost-LSTM neural network prediction model has higher accuracy than the time series prediction model, which can provide an important scientific basis for the supermarket chain to make sales forecast.
Design of an Adaptive Sidelobe Cancellation Algorithm for Radar
Authors: Hong Tian
Published: February 2021

In complex electromagnetic interference environments, adaptive sidelobe cancellation is an effective measure to suppress radar active jamming. It adopts spatial filtering technology, which can effectively suppress sidelobe interference[1]. In this paper, the basic theory of adaptive sidelobe cancellation system is introduced, and two commonly used algorithms are briefly introduced. In practical application, the cancellation effect decreases due to many factors. In order to improve the performance of adaptive sidelobe cancellation, this paper proposes a method of adaptive acquisition of interference sampling data, and uses this method to simulate and analyze the collected jamming data. Now the device function is becoming more and more powerful, and the system hardware platform has also developed rapidly. Compared with the traditional method, this new interference data sampling method has certain advantages and is of practical significance. At the same time, the problems that should be paid attention to in engineering implementation are put forward.
Assessment of the passenger aircraft mass and efficiency with a fuselage without portholes
Authors: Menouni Abderrafie El , Kretov Anatolii , Zhijin Wang
Published: February 2021

The problem of evaluating the effectiveness of reducing the weight of the aircraft and, in particular, the use of the concept of “fuel efficiency” is considered. For the design (operational) mass analysis, the mass state equation is used, on the basis of which the method of mass growth coefficients is constructed. The most widely used short-haul and medium-haul passenger aircraft of the B737 and A320 types are considered as an example of the application of this technique. The authors suggest to reduce the weight of the aircraft structure to switch to the fuselage without portholes. In the present work, this decision is assessed from the point of view of saving fuel weight.
Research on mission characteristics-based evaluation model of flight test workload
Authors: Mi Yi , Wang Anli , Song Hao
Published: February 2021

As a product of modern industrial cutting-edge technology, a large civil aircraft needs to undergo rigorous flight test before entering the aviation market, which fully ensures the safety of aircraft and its system. This makes the aircraft meet the airworthiness standards and requirements. The flight test of civil aircraft is a complex system project, which the top-level planning throughout the flight test period has an important influence on progress control and flight test efficiency of a new type aircraft. The core content of the top-level plan is the evaluation of flight test workload with consideration of test aircraft quantity. This paper proposes a flight test workload analysis and evaluation model based on the types of test missions through the analysis of the characteristics of civil aircraft flight test mission, which provides a feasible method for quantitative evaluation of flight test workload.
Text data-augmentation using Text Similarity with Manhattan Siamese long short-term memory for Thai language
Authors: Phreeraphattanakarn Thananya , Kijsirikul Boonserm
Published: February 2021

In this paper, we address the issue of using small text datasets for learning of neural networks. We explore the method that is used with image and sound datasets to augment data for increasing the performance of models. We then leverage this data augmentation technique to expand the training set of textual data. A great challenge in our dataset is that the amount of data is insufficient for training models. For this reason, we propose a method for augmenting text data specifically for Thai language which is based on Text Similarity and using the model to determine the semantic relationship between two sentences. The experimental results indicated that our proposed method is able to improve the performance of text classification.
Sectioning of branches of distribution networks with connected wind power plants
Authors: Bakardjieva J N , Matsankov M I , Slavov Svatoslav
Published: February 2021

The paper presents a developed algorithm for coordinating the response times of the devices for automatic sectioning of bilaterally power supplied lines, of the digital relay protection and the reclosers in medium-voltage distribution networks with connected wind power plants.
An Experimental Model of the Collect/Report Paradigm
Authors: Ivanova Krassimira Borislavova
Published: February 2021

In the Big Data community, the “Map/Reduce Paradigm” is one of the key enabling approaches for meeting the continuously increasing demands on computing resources imposed by massive data sets. Today it is implemented in many open source projects. The popularity of Map/Reduce is due to its high scalability, fault-tolerance, simplicity and independence from the programming language or the data storage system. At the same time, Map/Reduce faces a number of obstacles when dealing with Big Data. A possible solution of them may be the Collect/Report Paradigm (CRP) and Natural Language Addressing (NLA) approach. It is suitable for storing Big Data in large information bases located on different storage systems – from personal computers up to cloud servers. An experimental Model of the CRP is presented in this paper. An experimental implementation of the CRP to process and store data is outlined. The structures of the input and output data are in the form of RDF triplets. The ease of implementation of this model and the benefits of its use are discussed.
On-site research with a thermal camera on industrial heating
Authors: Yosifova Veneta , Stoimenov Nikolay , Haralampieva Milena
Published: February 2021

This paper submits the on-sight research made with a thermal camera for investigating the practices of heating technologies in industrial premises. The experiments are made during the winter season of 2019/2020 and give a preliminary overview of the heating methods, their positive and negative effect, and their contribution to energy consumption and efficiency. Models for worker’s practices and space zoning are observed to optimize heat distribution. Based on the experimental work a series of findings are made and described for future recommendations in heating systems design for industrial buildings.
Research of design an educational modular 5 axis milling machine
Authors: Anania F D , Pena A E , Canarache R M
Published: February 2021

Industrial CNC machine tools are supplied as closed architecture systems. Their structure, kinematics and CNC controllers are designed to be used exclusively for their basic purpose, without any possibility of being changed. Reconfiguration is seen as the ability to add or remove modules from the machine, to be equipped with additional degrees of freedom (axes). For the concept to become a reality, it is necessary that the machine tool can be easily assembled and disassembled by an end-user and can adapt to changing projects or machining requirements. The approached of this research was to develop a 5-axis modular machine tool, with technological capabilities similar to industrial ones, at an affordable level of development costs and suitable to be used for teaching CAM techniques for future engineers.
Review of existing methods and tools for part processing limited to polyhedral surfaces
Authors: Vasileva D , Lefterov E
Published: February 2021

Looking retrospectively at the many years of efforts by a number of researchers to develop a method for machining by cutting of polyhedral parts, it is found that the obtained results were not particularly satisfactory. For this finding, it is not possible to substantiate justify the basis in this paper, but the reason can be briefly indicated. One of the less successful methods has been created, though unintentionally, on the basis of fundamental kinematic cutting schemes (FKCS). The uniform rotary motion B, of the stock is kinematically related to the straight-line reciprocating motion C of the simple lathe cutting tool. Uniform, straight forward motion is also performed from the stock and it is a longitudinal feed movement. This method has some disadvantages: changing the actual angles of the tool during very wide cuts between 0° to 45°; variable size chip which is a source of periodic force loading of the tool and the stock and the correct reciprocating motion is realized by a CNC machine and the deviations from the exact shape being copied relative to the shape of the part surface of the machined area.
Fuel consumption and emission improvements obtained using a mild hybrid electrical system on a vehicle equipped with a manual gearbox
Authors: Saragea Ștefan , Frățilă Gheorghe , Badea Gabriel
Published: February 2021

The latest emission requirements for vehicles requires major improvement in vehicles fuel consumption and emission performance. For entry level range of vehicles, in order to keep the production costs low, the simplest choice of hybridization is the mild-hybrid system with integrated starter-generator (ISG). This paper contains a model of a mild-hybrid electric vehicle equipped with a manual gearbox and a model of conventional vehicle with focus on the emission performance. The goal of this paper is to find out the fuel consumption and emission of a mild hybrid electric vehicle by simulation and to show the improvements compared to a similar vehicle equipped with a conventional powertrain.
Simplified mathematical model for frontal impact study
Authors: Manea A M , Iozsa D , Stan C
Published: February 2021

The structure of the front compartment is built to provide safety to passengers during an impact. Safety is ensured by designing structures capable of taking up much of the impact energy. During an impact, the energy of the impact is consumed by the ability of the body structure to deform. Thus, a large part of the kinetic energy of the impact is transformed into deformation energy. It ensures that decelerations are reduced in a short period of time to the limit that passengers can bear. Two mathematical models are proposed for the study of the frontal impact between two vehicles. In the mathematical model the component elements of the frontal compartmental structures are treated separately. Two simplified numerical models with two degrees of freedom are proposed. The first mathematical model is of the table-spring type, and the second is the mathematical model of the table-spring-shock absorber type. The body elements and the main subassemblies of the vehicle are considered to be two concentrated table bodies. The connection between these bodies will be made by elastic elements and damping elements. Based on Lagrange’s generalized equations, the equations of motion necessary for the impact study will be obtained. Furthermore, the solving of the numerical systems of the proposed models will be done with the help of the modelling, simulation and analysis environment offered by the MATLAB Simulink software. In this environment, the main initial parameters and impact conditions between the two bodies will be established and block schemes will be built for both systems of equations. With the help of these mathematical models it is desired to determine the maximum deformation recorded by each vehicle during the frontal impact between the two.
The influence of combustion properties of fuel materials upon human evacuation in case of fire
Authors: Grigoras Z C , Ibanescu M
Published: February 2021

The purpose of this article is to analyze the variation of the tenability criteria (convected heat, radiant heat, toxic gases and smoke visibility) on the main evacuation paths inside of an educational building, in case of fire. The analysis is performed by numerical simulation for three different fire scenarios. The fire load density of fire space (an office type room) is the same, but the main combustible material is changed: wood, plastic and polyurethane foam. The analyzed building can house a great number of people (over 600) and its inner atrium could facilitate the spread of smoke and hot gases in case of a real fire. According to the numerical analysis, it has been concluded that the convected heat variation is not a significant one (within the engineering limits), but the radiant heat, toxic gases and smoke visibility are highly dependent on the type of considered combustible materials.
Date preparation module of automated metallurgical products production system
Authors: Ponomareva O , Porshnev S , Borodin A , Mirvoda S
Published: February 2021

The article discusses the data preparation module of the automated metallurgical production system, which provides data to obtain from heterogeneous sources (ASS, CIS, MES, ERP systems ), convert heterogeneous data into a convenient form for subsequent storing, configure the converting rules and output heterogeneous data relevant to the query. Proposed components of the data preparation module: logical structure of data preparation module, algorithm of data preparation module operation, the link with simulation modeling and other modules, the list of technical equipment. A fragment of the interface of the data preparation module is being converted.
Forming the straight flange of a rib by pulsed-magnetic field pressure
Authors: Kurlaev N V , Matveev K A , Ahmed Soliman M E , Detinov M B
Published: February 2021

In the production of aircraft, the most common method of manufacturing a straight flange is magnetic-pulse stamping, since it is highly efficient in small-scale production due to its high versatility and simplicity of technological equipment. Among the sheet metal parts of the aircraft, there is a fairly large number of parts with straight sides, which are made of a flexible elastic medium. In this paper, the straight flanging of the D16AM aluminum alloy during magnetic pulse forming was investigated by using the LS-DYNA simulation program. The operation of sheet bending is used to form the side wall of the part. If the bent side has a straight shape, then bending stresses occur along the bend radius, and the side wall remains unstressed. This operation is called «straight flange bending». With impulse shaping, there is a great possibility to control the shape of the workpiece during deformation by distributing pressure over its area. Excessive pressure is created on the workpiece after it adjoins the die. This pressure contributes to the redistribution of stresses and equalizes them along the height of the section of the workpiece, while inertial forces change the stress-strain state of the workpiece. This study, in particular, concerns an example of numerical simulation of the electromagnetic forming of a straight flange with the obtained mesh shape of a workpiece and the results of its calculations were summarized in the form of a nomogram.
Evaluation of the efficiency of dry electrostatic cooling by the transfer current
Authors: Khripunov N V
Published: February 2021

Practical examples and physical mechanisms of dry electrostatic cooling efficiency when processing materials by cutting are considered. The assumption is made that efficiency of dry electrostatic cooling process depending on the mode of equipment operation directly depends on the value of electric charge carried by air flow - transfer current. A stand has been developed to measure the current flowing from an grounded plate under the action of dry electrostatic cooling airflow. Using the stand, experiments were made with the «Varkash» dry electrostatic cooling unit. As a result of the experiments, a relationship was found between the transfer current from air pressure and the length of the air flow. Experiments were made on turning structural steel with high-speed steel tools, varying the air pressure of the dry electrostatic cooling unit and the distance from the nozzle to the cutting zone. Based on the results of the experiments, it was verified that the transfer current corresponds to the efficiency of dry electrostatic cooling during cutting.
Perspectives for use of composite and polymer materials in aircraft construction
Authors: Zolkin A L , Galanskiy S A , Kuzmin A M
Published: February 2021

One of the main indicators characterizing the quality of modern products are reliability indicators. The detection and development of effective measures to combat corrosion of aviation materials and structures is one of the most important areas of ensuring safety, high operational reliability and efficiency of modern aviation technology. It is one of the modern trends in the development of aviation at this stage of development of aircraft construction. This article discusses the technological aspects of the development of the use of composite materials in aircraft construction at the present stage of society development. The aircraft industry is one of the high-tech industries where modern polymer and composite materials play a decisive role. In this regard, the development of composite and polymer materials is the future of all the world aviation.
Optimization of the combined beneficiation scheme and increase in the performance of highly efficient refractory gold-bearing ores under development
Authors: Askarova G Y , Shautenov M R , Nogaeva K A
Published: February 2021

The growth in consumption and cost of precious metals is forcing gold mining companies to expand their raw material base and study and develop processes aimed at increasing the recovery of gold from ores and concentrates. The reserves of rich, easily-enriched gold-bearing mineral raw materials are practically exhausted. To maintain the volumes of extraction of precious metal, the domestic gold-extracting industry constantly involves new gold deposits in processing, resumes operation of previously abandoned and “mothballed” quarries and landfills, mines and mines, processes man-made dumps of many mining and processing plants containing a certain amount of metals (in as associated components or not completely extracted during primary processing).
Classification of objects of technological preparation in the machining production
Authors: Bazrov B M
Published: February 2021

As the main objects of technological preparation for the production of parts, the part, the technological process of its manufacture, the machine tool, the machine retaining device, and the tool setup are considered. The analysis of the classifications of the listed objects showed the absence of full-fledged classifications of parts, technological processes for their manufacture and instrumental setups; the classification of machine tools and machine retaining devices does not reflect the links between them and the technology of parts manufacturing. The noted shortcomings of the listed classifications lead to an increase in labor intensity and a decrease in the quality of technological preparation of production. The article describes a methodological approach to the construction of technological classifications, reflecting the relationship between objects and the technology of parts manufacturing. Characteristics of the objects associated with the technology of parts manufacturing are proposed as distinctive features for the construction of technological parts classifications, technological processes, machine tools, machine retaining devices and instrumental setups. The use of technological classifications will reduce labor intensity and improve the quality of technological preparation of production.
Differential mode pulse minimization by using the genetic algorithm in the bus
Authors: Gazizov Rustam R , Gazizov Ruslan R , Gazizov T T , Kalinina M N
Published: February 2021

The article considers an optimization of a spacecraft component. The choice of length of the power supply was carried out using a genetic algorithm. The main purpose was decreasing the maximum voltage amplitude in the power supply bus. As an excitation we used a differential excitation of a trapezoidal pulse. Comparison of the results of signal simulation after optimization for two approaches is presented, that differed by various numbers of chromosomes and populations. It was found that the two approaches are not differ significantly in the simulation results. We decreased the maximum voltage amplitude by 270 times with using the genetic algorithm.
Linguistic approach to the classification problem based on the multiset theory
Authors: Demidova L A , Sokolova Ju S
Published: February 2021

The problem of developing generalizing decision rules for object classification, which arises under conditions of inaccurate knowledge about the values of objects’ attributes, and about the significance of the attributes themselves, has been considered. The approach to the binary classification of objects, which implements the representation of inaccurate knowledge based on linguistic variables and allows one to consider various strategies for the formation of generalizing decision rules for classification using the tools of multiset theory, has been proposed. The example of the formation of generalizing decision rules of binary classification for the set of competitive projects evaluated by the group of experts, confirming the effectiveness of the proposed approach, has been considered. A herewith, visualization of objects, the values of the features of which are the frequency of setting a certain score according to the a priori given rating scale by all experts, in a two-dimensional space using the non-linear dimensionality reduction algorithm named as the UMAP algorithm, has been implemented. Based on the results of visualization and cluster analysis of the initial set of competitive projects, the “noise” project, which negatively affects the results of the formation of generalizing decision rules of binary classification, was identified and removed from further analysis.
Parametrization of bass diffusion model on COVID-19 first wave data
Authors: Škraba A , Vavtar B , Stanovov V , Semenkin E , Stojanović R
Published: February 2021

The paper addresses the development of the system for the parameterization of the Bass Diffusion Model on Covid-19 Data. Continuous model developed by the principle of system dynamics is presented. The parameters of the model are tuned to fit the data with genetic algorithm in Powersim simulation tool. The validation is performed by standard simulation validation techniques. The input data used in the experiments were gathered by publically available databases. In particular, the data collected in Austria, France, Italy, South Korea, Slovenia and Swiss were considered in this study. The results have shown that the simple model with is capable of predicting the growth with S-shaped curve with high accuracy.
A reliability index for fuzzy expert group criterion
Authors: Poleshchuk O
Published: February 2021

In the paper, a fuzzy expert group criterion is presented in the form of a linguistic variable with the properties of completeness and orthogonality. The expert group criterion is created based on individual expert criteria of evaluation a quantitative or qualitative characteristic. The construction is carried out on the basis of the minimum loss of information contained in the individual criteria. For neighboring terms (concepts) of the criterion, analogues of probabilities of errors of the first and the second kinds are determined, as well as the reliability index, taking into account the zones of uncertainty of their membership functions. The reliability index of fuzzy expert group criterion is determined based on the reliability indexes of all the neighboring terms.
Problems of personal data and information protection in corporate computer networks
Authors: Zolkin A L , Abdulmukminova E M , Malikov V N , Lepshokova A N
Published: February 2021

The article discusses the problems of personal data and information protection from intruders as well as methods of authentication and identification in corporate networks. Various methods of authentication and identification in computer networks are presented. Their comparative analysis is carried out, the features and disadvantages in various areas of use are highlighted, risks and possible damage from violation of data confidentiality are analyzed. The magnitude of violations of confidentiality, availability and integrity of information is growing every year, at the same time, the caused damage is growing. This situation makes it necessary for information security specialists to analyze all the risks of illegal access to information more and more thoroughly, and then resort to the introduction of modern means authentication, use new encryption methods, increasingly generate new passwords to access the system. Today, there are many ways and methods of authentication, but the specific of their application depends on the location of the information storage and its value. Meanwhile, authentication methods are not perfect protection methods, they are also vulnerable and here the situation is mostly depends on the skills of the attackers. In addition, the article discusses the problems of information security threats to flash drives, analyzes the FAT32 and NTFS file systems of flash drives as well as their vulnerabilities to malicious programs. The features of the algorithm of virus action on flash drives are highlighted. Today, there are many ways and methods of flash drives protection, but the specifics of their use depends on the location of the information storage and its value.
Analysis of unilateral event-continuous systems
Authors: Shornikov Yu V , Popov E A
Published: February 2021

Numerical analysis of unilateral event-continuous processes in comparison with traditional simulation algorithms for discrete-continuous systems is addressed. An original integration step size control algorithm guaranteeing correct detection of unilateral events is given. The algorithm is tested on a typical problem. Simulations are carried out in modern computer environments for modeling and simulation of complex dynamic systems of the mentioned class. A comparative analysis of the application of the software environments to event-continuous processes with unilateral events is presented.
Development of repository of deep neural networks for the analysis of geospatial data
Authors: Yamashkina E O , Kovalenko S M , Platonova O V
Published: February 2021

The article proposes a solution for organizing a storage of artificial neural networks in a digital spatial data infrastructure system. Based on the analysis of world experience, a register of key storage cases was created, which made it possible to create an effective solution for analyzing large arrays of spatial data. The structure of the neural network sets the format of the input data and the type of the output signal. It is shown that the use of neural networks for solving design problems requires dividing the storage of the ontological model into machine learning, data and task modules. The introduction of deep learning models into the repository will allow not only to form an ANN system capable of solving urgent problems in the field of analysis of different types of big data, but also to solve the problem of choosing an effective model by building a system of recommendations that optimize the choice of algorithms.
Simplified solution to the problem plane-parallel motion partial control of an autonomous rigid body in incompressible stratified viscous fluid
Authors: Kuznetsova L V , Firsov A N
Published: February 2021

The report presents a mathematical model of the motion control of an autonomous solid body moving in incompressible stratified viscous fluid and analytical and numerical analysis of this model. It is assumed that the body does not have its own propulsion system, but is equipped with controlled rudders - wings of finite span. The body is moved by the influence of the buoyancy force and wings lift. Partial movement control is achieved by the angle of attack of the wing change (for ensuring access to the given point by this solid body). This body motion is considered to be plane-parallel motion.
Experience and prospects of using robotics in the nuclear power industry
Authors: Tochilin A V , Voronkov I E , Alabin A V
Published: February 2021

It is impossible to imagine the modern nuclear power industry without the use of robotics. Monitoring of equipment and structures conditions, elimination of accidents and catastrophes consequences are wide application areas of robots that allow to reduce the radiation load on personnel. In the near future, the global nuclear power industry will inevitably face the need to decommission nuclear power plants that were built in the 1970s-1980s, which currently form the core of nuclear generation. This determines the high relevance and importance of developing scientifically grounded methods and approaches to decontamination and dismantling of nuclear power plant radioactive structures with the preferential use of robotic technology. A review of domestic and international experience in the use of industrial and specialized robots in the field of nuclear energy allows us to assess the state and prospects of this direction, as well as to recognize the discrepancy between the existing technological level of robotic means and the promising tasks in the field of decommissioning of industrial nuclear reactors. In this case, it is considered appropriate and relevant to rapidly develop robotics as well as information simulation models that allow to provide various scenarios for dismantling of radioactive structures and equipment with the greatest involvement of modern robotic systems in this process.
Analysis of options for small solar power plants for the Republic of Khakassia of the Russian Federation
Authors: Toropov A S , Platonova E V , Chistyakov G N , Kolovsky A V
Published: February 2021

The analysis of electricity tariffs for consumers of the Republic of Khakassia of the Russian Federation has been performed. Tariffs for the population are quite low. The use of small solar power plants for private residential buildings is inexpedientl due to the long payback period. Tariffs for legal entities and organizations are much higher than for the population and have a steady upward trend. The main consumption of electricity by such consumers occurs during daylight hours. That is much in line with the energy generation by solar panels. It is concluded that calculations are necessary to determine the expedience of using small solar power plants for this group of consumers. The classification of the types of low-power solar power plants is given, their advantages and disadvantages are highlighted, and the area of application is shown. The results of the comparative analysis of three types of small solar power plants for a state facility of the Republic of Khakassia are presented. The expediency of using small network solar power plants without electric storage batteries with a limitation of the power supplied to the network was substantiated.
High voltage waveform influence on ozonizer productivity on dielectric barrier discharge basis
Authors: Andreev V V , Vasilyeva L A , Pichugin Yu P
Published: February 2021

Influence of the high voltage waveform on productivity of a plasma-chemical ozone generator on the basis of dielectric barrier discharge (DBD) is studied. Experimental studies were carried out using of two types of AC high voltage: at first, AC high voltage (the voltage effective value is equal to U
2=11 kV), representing continuous periodically repeating inharmonic structures with frequency f
2=400 Hz; secondly, pulsed high voltage with the amplitude equal to U
p=20 kV, pulse width 50 ns, the pulse edge 20 ns and the pulse duration 2.5 ms (thus, the pulse repetition rate, in average, is equal to 400 Hz). For the second case, the productivity by ozone of the DBD cell is significantly higher.
Ultrasonic assisted turning of AISI 52100 steel using nanoparticle-MQL method
Authors: Ağar Salih , Tosun Nihat
Published: February 2021

High cutting force and high cutting tool-chip interface temperature occur during machining of high strength materials like AISI 52100 by using conventional turning method and this makes to the difficult machining operation. Besides, in conventional turning (CT) of these materials, which has high abrasion resistance and hardness properties, an additional process such as grinding is required to achieve the desired surface quality. Ultrasonic assisted turning (UAT) method has been widely used in the machining industry in recent years, as it exhibits better surface quality, lower cutting forces, and cutting temperature than the CT method. This paper focused on experimentally and statistically determining the effects of different cutting parameters and cooling conditions (dry and minimum quantity lubrication-MQL) on surface roughness, workpiece surface texture, tangential direction cutting force, and cutting tool-workpiece interface temperature in the machining of AISI 52100 material by using UAT and CT methods. The experimental results revealed that significant improvements determined in the cutting forces and the surface roughness occurred in UAT compared to CT in all the cooling conditions. However, the increasing cutting speeds caused to observe higher interface temperature values in dry turning by the UAT method. Variance Analysis (ANOVA) was carried out to determine the significance grade of independent variables on dependent variables. According to ANOVA results, while the cutting speed is the most important factor on the surface roughness and the cutting zone temperature, and the cooling method is the most important factor on the cutting force. The effects of turning methods on corresponding surface topography, including surface defects, were evaluated. It is determined that in the surface topography analysis, feed marks are the main texture of the workpiece in the CT method while micro-level indentations and protrusions occurred on the workpiece surface in the UAT method.
Behavior of phase transition of ZnO in nanoscale of time a molecular dynamics computation
Authors: Chergui Y , Aouaroun T , Hadley M J , Chemam R , Ouatizerga A
Published: February 2021

The phase transition of Zinc Oxide Wurtzite structure is investigated at the Nanoscale of time and space using Equilibrium Parallel Molecular Dynamics simulation. We extend existing results to higher pressure and temperature. The calculations ran on the RAVEN supercomputer of Cardiff University with DL_POL_4 software. The interatomic interaction modeled by Bukingham-Coulpmb potential for short and long-range interactions. We study the evolution in time of the total energy in isothermal and isobaric ensemble, to find the equilibrium time of the system, under the ranges of pressure 0–200(GPa) and temperature 300–3000(K), This is a new method to investigate the phase transition. Our results are closed to available theoretical and experimental data.
Effect of ‘genetic’ rare earth on alloy dissolution behavior in micro-alloyed steel
Authors: Wei Guomin , Li Minghe , Fang Qi , Sun Wei , Jin Zili
Published: February 2021

The solid solubility of alloying elements and microstructures of insoluble second-phase particles of micro-alloyed steel containing genetic and additional rare earth were respectively investigated. Experimental results indicate that adding a rare earth can change the inclusion morphology and promote the formation of a core of composite inclusions with Al, Ca, Mg, S, and a small amount of Ti. The extremely small quantities of genetic rare earth in steel can promote the formation of a solid solution of Nb and Ti. Therefore, although the content of genetic rare earth in steel is negligible, the promotion effect on solid solubility is significant. The addition of a rare earth has no effect on the types of the insoluble second-phase particles; however, it has a distinct dissolution effect on the large particles in steel.
Unprecedented ice loss predicted for Greenland
Authors: Ravilious Kate
Published: February 2021

Global warming is set to melt enough ice from the Greenland Ice Sheet over the next 80 years to reverse 4000 years of cumulative ice growth.
Optical tweezer pioneer Arthur Ashkin dies aged 98
Authors: Banks Michael
Published: February 2021

The US physicist Arthur Ashkin, who shared the 2018 Nobel Prize for Physics for his contributions to laser physics, died on 21 September aged 98.
Reflecting the community
Authors: Durrani Matin
Published: February 2021

Welcoming Physics World’s new pool of contributing columnists
Black hole diaries
Authors: Commissariat Tushna
Published: February 2021

John Moffat’s latest book, The Shadow of the Black Hole, is a comprehensive take on its fundamental concepts, as experienced in the most extreme of testing grounds – a black hole.
Overcoming roadblocks in computational roadmaps to the future for safe nanotechnology
Authors: Karakus Ceyda Oksel , Winkler David A
Published: February 2021

The rapid rise of nanotechnology has resulted in a parallel rise in the number of products containing nanomaterials. The unusual properties that nano forms of materials exhibit relative to the bulk has driven intense research interest and relatively rapid adoption by industry. Regulatory agencies are charged with protecting workers, the public, and the environment from any adverse effects of nanomaterials that may also arise because of these novel physical and chemical properties. They need data and models that allow them to flag nanomaterials that may be of concern, while balancing potential stifling of commercial innovation. Roadmaps for the future of safe nanotechnology were defined more than a decade ago, but many roadblocks identified in these studies remain. Here, we discuss the roadblocks that are still hindering the effective application of informatics and predictive computational nanotoxicology methods from providing more effective guidance to nanomaterials regulatory agencies and safe-by-design rationale for industry. We describe how developments in high throughput synthesis, characterization, and biological assessment of nanomaterials will overcome many of these roadblocks, allowing a clearly defined roadmap for computational design of effective but safe-by-design nanomaterials to be realized.
Reconfigurable chalcogenide phase change metamaterials: a material, device, and fabrication perspective
Authors: Mandal Avik , Cui Yihao , McRae Liam , Gholipour Behrad
Published: February 2021

Chalcogenide phase change semiconductors have played a crucial role in the evolution of photonic technologies. From their decades-long utilization at the core of optical disks to their emergence as a highly promising reconfigurable component for a variety of nanophotonic modulation, switching and sensing platforms, the field of optics has continuously recognized their potential and sought to engineer their properties through a variety of material, device and fabrication level schemes. Most recently, the integration of phase change semiconductors within various photonic metamaterials, metadevices and metasystems has ignited research interest worldwide. This has facilitated the development of a wealth of highly promising application-driven nanophotonic device platforms that address growing societal demands requiring higher data storage capacity, faster and more efficient telecommunication, as well as adaptive sensing and imaging with reduced size, weight and power requirements. Here, we present a comprehensive review on the evolution of reconfigurable phase change chalcogenide metamaterials that focuses not just on a device level perspective but also examines the underlying material and fabrication considerations that are critical to obtaining optimal performance in these groundbreaking devices.
Progress of graphene devices for electrochemical biosensing in electrically excitable cells
Authors: Williams Kelli R , Hashemi Nicole N , Riddley Mia , Clarke Gabriel , Igwe Nkechinyere , Elnagib Dena , Montazami Reza
Published: February 2021

Traumatic brain injury and other neurological disorders continue to affect many worldwide and demand further research. It has been shown that electrical signaling and ion channel flow and dynamics are disrupted over the course of a traumatic brain injury as well as over the course of other neurological disorders. However, typical devices used to measure ion flow and electrical signaling from the brain suffer from complexity, high expense, poor spacial and temporal resolution, and low signal to noise ratios. Graphene has emerged as an economical and simple alternative to sensing electrical and ionic signals in a variety of biological situations. This material has emerged as a power material due to its excellent strength, electrical conductivity, and biocompatibility. This review paper focuses on the advantages of the different graphene-based electronic devices and how these devices are being developed into biosensors capable of sensing neuronal ionic and electrical activity and activity from other electrically excitable cells.