bluuebunny/crossref_metadata_2025 huggingface dataset:
The AME 2020 atomic mass evaluation (II). Tables, graphs and references*
Authors: Wang Meng , Huang W.J. , Kondev F.G. , Audi G. , Naimi S.
Published: January 2021

This is the second part of the new evaluation of atomic masses, AME2020. Using least-squares adjustments to all evaluated and accepted experimental data, described in Part I, we derived tables with numerical values and graphs which supersede those given in AME2016. The first table presents the recommended atomic mass values and their uncertainties. It is followed by a table of the influences of data on primary nuclides, a table of various reaction and decay energies, and finally, a series of graphs of separation and decay energies. The last section of this paper provides all input data references that were used in the AME2020 and the NUBASE2020 evaluations.
The AME 2020 atomic mass evaluation (I). Evaluation of input data, and adjustment procedures*
Authors: Huang W.J. , Wang Meng , Kondev F.G. , Audi G. , Naimi S.
Published: January 2021

This is the first of two articles (Part I and Part II) that presents the results of the new atomic mass evaluation, AME2020. It includes complete information on the experimental input data that were used to derive the tables of recommended values which are given in Part II. This article describes the evaluation philosophy and procedures that were implemented in the selection of specific nuclear reaction, decay and mass-spectrometric data which were used in a least-squares fit adjustment in order to determine the recommended mass values and their uncertainties. All input data, including both the accepted and rejected ones, are tabulated and compared with the adjusted values obtained from the least-squares fit analysis. Differences with the previous AME2016 evaluation are discussed and specific examples are presented for several nuclides that may be of interest to AME users.
Inverse Problem Solving Approach Using Deep Network Trained by GAN Simulated Data
Authors: Krylov Sergei , Krylov Vladimir
Published: January 2021

In this paper authors deal with tasks of reliably recover a hidden multi-dimensional model parameter from indirect process observations. Such task is known as inverse problem. There are a lot of inverse problems that have practical value, for example in seismic wave propagation, low-dose tomography. To solve many of these problems in a practical style, this article proposes an approach based on the many simulations of the corresponding forward problem and using the set of simulation data as the training dataset. Most of physical processes have computer models that generate precise results. The existing simulators provide ways to predict process output by input parameters. A difficulty in solving of most inverse problems is that the solution is sensitive to variations in data, which is referred to as ill-posedness. From broad spectrum of methods to overcome ill-posedness authors use machine learning model trained on special simulated data. The paper describes the deep network model using some regularization. The key idea is to use Generative Adversarial Network (GAN) to generate correct input parameters values and support the unique existence. This network is trained by parameter examples that are real solutions of inverse problem. The small manually built dataset transforms to infinite dataset automatically by GAN. The augmented dataset feeds the simulator to get output data to train deep learning network. The network has regularization layers to support stability. The paper describes details of this model using deep augmentation to solve inverse problems on the easy example: the task of throwing a heavy ball at an angle to the horizon, taking into account the force of friction against air.
wUUNET: advanced fully convolutional neural network for multiclass fire segmentation
Authors: Bochkov Vladimir , Kataeva Liliya
Published: January 2021

This paper describes a solution of computer vision task concerning multiclass fire segmentation to get and show location of red, yellow and orange flame. We use UNet model as the best open-sourced convolutional neural network baseline. Based on this model we introduce UUNet-concatenative and wUUNet models. Since the multiclass fire segmentation task is solved for the first time in science, we collect the appropriate dataset and use the dataset-labeling alignment via look-up-tables. Also we compare models trained by Soft Dice and Jac-card indexes in combination with binary cross-entropy as a loss functions. Paper shows the problem of accuracy loss at bounding nodes of splitting the frame. As a solution we introduce combinational methods of partially intersected areas. The comparison of the used models and calculation schemes is demonstrated and the corresponding conclusions of the investigation are made.
Synthesized optimal control based on machine learning
Authors: Diveev Askhat , Shmalko Elizaveta
Published: January 2021

The article discusses symbolic regression methods as a machine learning technology. The technique is tested on a complex problem of control systems synthesis. A new type of control based on changing the position of a stable equilibrium point is proposed. The implementation of such control requires the construction of a double feedback loop. The inner contour ensures the stability of the control object relative to some point in the state space. The outer contour provides optimal control of the stable equilibrium point position. To implement control, symbolic regression methods are used as machine learning technologies. It is shown that such a control is the least sensitive to external disturbances and model uncertainties.
The effect of density thresholding on the EEG network construction
Authors: Zakharov Ilya , Adamovich Timofey , Tabueva Anna , Ismatullina Victoria , Malykh Sergey
Published: January 2021

The procedure of thresholding for graph construction is one of the common steps in calculating networks of brain connections. However, this procedure can lead to incomparable results from different studies. In the present study we aim to test the effect of thresholding or algorithmic reduction of the number of connected nodes on the construction of a set of widely used connectivity graph metrics derived from EEG data. 164 people took part in our study. Participants were recruited via social networks. EEG was recorded during resting state. At the beginning of the procedure each participant was asked to relax and not to think about anything. Source reconstruction was performed using standard source localization pipeline from MNE-package. Desikan-Killiany Atlas was used for cortical parcellation with 34 ROI per hemisphere. Synchronization was estimated with weighted phase lag index in 4–30 Hz frequency range for eyes closed and eyes open separately. We have found that All metrics except average participation coefficient vary monotonously as a function of density level (moreover, we have found, that for Cluster Coefficient, more than 95% and for the Characteristic Path Length ∼50% of the variance is related to thresholding cut-off). The different data-driven approaches to the network construction leads to significant changes in the group-level graph metrics and can eliminate the variance in the data that can be crucial for individual differences studies.
A system for off-line validation of medical data in DICOM archive
Authors: Magomedov SH G
Published: January 2021

The problem of consistency of medical data in Hospital Data Management Systems is considered in the context of correctness of medical images itself to minimize possible harm from spurious DICOM files. The approach should be considered as an addition to other securing techniques like watermarking, encrypting, testing conformance with the standard. To achieve amenable accuracy in practice two aspects are taken into account: correctness of periodicity and correctness of image data (time series) itself for considered modality. This paper proposes an architecture of an information system and network filter integrated to it to provide facilities for analysis and alert management. The architecture is designed to perform the analysis of incoming data streams within components working in a clustered manner, providing horizontal scalability and fault tolerance to be BigData-ready.
The effective interaction of the models of classification with the usage of auction heuristics
Authors: Barakhnin V B , Kozhemyakina O Yu , Pastushkov I S
Published: January 2021

The article proposes the approach that allows to make multi-model systems of classification systems more suitable for solving the practical problems in the field of information technologies. To achieve this, it was necessary to provide a stable system response time to support SLA (service-level agree-ment) and, on the other hand, to minimize the downtime of server hardware. The first requirement would allow to give the requests correctly and quickly to the client, and the second one would make the cost of renting servers more justified. The main idea of the proposed approach is to obtain the pre-dictions with the highest possible accuracy in a fixe time. We considered three auction models: Dutch auction (rate decreasing), English auction (rate increasing) and the adapted version of Vickrey auction (highest rate switched off). In all cases, we used the highest probability of the mark as a rate, and we set a time parameter, after which the prediction is recognized as final. The obtained results and their comparison with the methods of ensembling and balancing allow us to conclude that the proposed approaches can be use-ful in the development of multi-model systems of classification.
Generation of echocardiographic 2D images of the heart using cGAN
Authors: Zyuzin Vasily , Komleva Julia , Porshnev Sergey
Published: January 2021

One of the most significant tasks of echocardiography is the automatic delineation of the cardiac structures from 2D echocardiographic images. Over the past decades, the automation of this task has been the subject of intense research. One of the most effective approaches is based on the deep convolutional neural networks. Nonetheless, it is necessary to use echocardiogram frames of the cardiac muscle, which show the boundaries of the cardiac structures labeled/annotated by experts/cardiologists to train it. However, the number of databases containing the necessary information is relatively small. Therefore, generated echocardiogram frames are used to increase the amount of training samples. This process is based on the ultrasound images of the heart, annotated by experts. The article proposes an improved method for generating echocardiograms using a generative adversarial neural network (GAN) with a patch-based conditional discriminator. It has been demonstrated that it is possible to improve the quality of generated echocardiogram frames in both two and four chamber views (AP4C, AP2C) using the masks of cardiac segmentation with sub-pixel convolution layer (pixel shuffle). It is demonstrated that the proposed approach makes it possible to generate ultrasound images, the structure of which corresponds to the specified segmentation masks. It is expected that this method will improve the accuracy of solving the direct problem of automatic segmentation of the left ventricle.
Computer vision system for the automatic asbestos content control in stones
Authors: Zyuzin Vasily , Ronkin Mikhail , Porshnev Sergey , Kalmykov Alexey
Published: January 2021

The paper discusses the results of the first stage of research and development an innovative computer vision system for the automatic asbestos content control in stones veins at an asbestos processing factory. The discussed system is based on the applying of a semantic segmentation artificial neural networks, in particular U-Net based network architectures for solving both: the boundaries of stones segmentation and veins inside them. At the current stage, the following tasks were solved. 1. The discussed system prototype is developed. The system is allowing to takes images of the asbestos stones on the conveyor belt in the near-infrared range (NIR), avoiding the outer lighting influence, and processing the obtaining images. 2. The training, validation and test datasets were collected. 3. Substantiated the choice of the U-Net based neural network. 4. Proposed to estimate the resulted specific asbestos concentration as the average relation of all the veins square to all stones square on the image. 5. The resulted deviation between obtained and laboratory given results of the asbestos concentration is about 0.058 in the slope of graduation curve. The farther improvement recommendations for the developed system are given.
Unknown word handling in structured text classification
Authors: Silaeva Anastasiya , Balk Igor
Published: January 2021

In the NLP task, high priority was accorded to the accumulation of vocabularies. To complement them, you need to find unknown words. Unique words with the help of an expert can be determined in the dictionary. This paper presents a technique for finding unknown words in Named Entity Recognition (NER).
Classification of negative publication in mass media using topic modeling
Authors: Yakunin Kirill , Mukhamediev Ravil , Kuchin Yan , Musabayev Rustam , Buldybayev Timur , Murzakhmetov Sanzhar
Published: January 2021

The paper proposes a method for evaluating text documents by arbitrary criteria, combining the topic modeling on the text corpora and multiple-criteria decision making. The evaluation is based on an analysis of the corpora as follows: the conditional probability distribution of media by topics, properties and classes is calculated after the formation of the topic model of the corpora. Weights assigned by experts to each topic along with topic model can be applied to evaluate each document in the corpora according to each of the considered criteria and classes. The proposed method was applied to a corpus of 804829 news publications from 40 Kazakhstani sources published from 01.01.2018 to 31.12.2019, in order to classify negative information on socially significant topics. A BigARTM model was calculated (200 topics) and the proposed model was applied. Experiments confirm the general possibility of evaluating the sentiment of publications using the topic model of the text corpora, since ROC AUC score of 0.93 was achieved on the classification task.
Water environment monitoring with an autonomous unmanned surface vessel
Authors: Chensky D A , Aisuev B B , Chensky A G , Fedotov A P , Poletaev A S
Published: January 2021

The paper discusses the use of catamaran-type ultra-small unmanned vessels for studying lakes, rivers and different offshore areas. The key features of a surface vessel designed in Irkutsk Technical University are presented. The article describes major systems of the vessel and concepts of autonomous functioning and remote control. The apparatus can fulfil automatically mapping, searching of sunken objects, hydroacoustic scanning of bottom relief and underwater video recording without the use of additional boats. It is capable to inspect 100 linear kilometers (∼15 km2) of the water area per one day. The use of solar panels and Li-ion batteries charged during a single sunny day allows it to work for several days without use of any external sources of energy for recharging. All systems have been checked and debugged in the laboratory and the designed vessel was tested in Irkutsk reservoir. The field testing showed that the error of coordinates determining was within 2 meters. The planned and actual routes almost coincided with an accuracy better than 3 meters.
Application of particle-size analysis in various industries
Authors: Gerasimov A M , Eremina O V , Cherkasova M V , Dmitriev S V
Published: January 2021

For various materials, rapid generation of results is always critical. Particle-size analysis of processing products using a laser-based particle-size analyzer is a valid alternative to the traditional sizing test. The article presents the results of studies conducted using Microsizer 201C equipment by the example of layered aluminosilicates and metal powders for additive manufacturing. The size analysis for these products is generally complicated by their ability to stick and agglomerate. Ultrasonic mixing does not harm the material analyzed and promotes uniform distribution of the sample during analysis. The results of granulometric analysis of kaolin ores obtained after different heat treatment are presented. The results of air-electric classification of metal powders obtained after vibration disintegration of metal chips are presented. The variety of raw materials shows a wide range of applications of this method in industry.
Moving object recognition system on a pedestrian crossing
Authors: Semenova E I , Kyarimova Sh D , Kukartsev V V , Leonteva A A , Ogol A R , Bondarev A S
Published: January 2021

The article discusses the development of a system for recognizing people at a pedestrian crossing. The recognition system includes a trained classifier and two sets of images taken from an open database containing images of city streets from outdoor cameras. Input information prepared using PictureCropper application. The classifier was tested based on the prepared sets of images. The result is shown in the figure, and after testing, the metrics were calculated, necessary to assess the effectiveness of the resulting classifier for each set. System is being developed for specialists, which will allow individual and centralized adjustment of the adjustment of pedestrian phases for each road situation, both for the local system of controllers, and in accordance with the existing algorithms of coordination systems with the expansion of such.
Scanning steel junctions using eddy current probe
Authors: Ishkov A , Malikov V , Dmitriev S , Fadeev D , Katasonov A , Rykova K
Published: January 2021

The aim of this research is the process of developing a miniature probe for studying electrical steel. The issue of safety when using the products made of this type of steel, assessment and forecast of their quality make this topic relevant. We have found it possible to study the characteristics of steel at different depths by changing the signal amplitude generated by the eddy current probe. The novelty of this research is due to the use of a superminiature eddy current probe of a transformer type that can perform point measurements (0.05 mm sections) of ferromagnetic materials using the eddy current method and is based on the study of conductivity of electrical steel. A hardware and software package is designed based on the developed probe. It can test steel at its boundary with a dielectric. A system that can automatically move the probe over a controlled object at a preset speed has been developed. The study consisted of continuous and discrete measurements that were made by moving the probe over a ferromagnetic and dielectric material at a given speed and scanning the object in 0.1 mm increments. The results of the test performed on samples at different measurements and at different frequencies from 2000 to 20000 Hz are indicated. The study showed that the magnetic field lines of steel, which occur as a result of the impact of the eddy current probe on the ferromagnetic material, have a strong effect on the signal received by the eddy current probe after it is removed from the controlled object at a distance of 1 mm. The signal frequency on the exciting coil of the eddy current probe has a significant influence on this process. The conducted tests have demonstrated the nonlinear nature of the dependency of the probe response when it passes through the steel-dielectric boundary; the mathematical regularity of this dependency is revealed. The effect of the gap between the eddy current probe and the object of study is also analyzed.
Evaluation of the effectiveness of dust screens and the possibilities of taking into account their influence in software models
Authors: Ivanov A V , Strizhenok A V
Published: January 2021

The variety of approaches used to reduce dust load from the enterprises of the mineral resource complex is wide. Often the normative methodological base shows a lag behind the development and implementation of new devices and methods of protection. The article considers an example of a granite quarry in the Leningrad region of Russia, on which the construction of dust screens was proposed. The impact of the enterprise’s facilities on the residential area has been assessed. The inverse subsurface nature of the movement of air and the spread of dust from quarry facilities is revealed. Proposed placement of a semi-permeable dust screen along the edge of the quarry provides comprehensive dust protection. An assessment was made of the negative impact of the facility on atmospheric air after installing a dust screen with various options for methodological accounting for the impact of such structures on reducing dust transfer outside the quarry field.
Physical principles of operation and basic capabilities of the four channel receiver 1288хк1т (mf-01)
Authors: Nikitin P V , Ryabov I V , Bazhenov R I , Gorokhova R I , Zueva T G
Published: January 2021

In radar detection and radio navigation ensuring the reception of signals transmitted over the meteor channel of radio communication is often controversial[1-3]. Solving these problems requires the ability to synthesize precision signals directly[4, 5] for heterodyning systems in addition to modern analog-to-digital conversion devices, correlation analysis, and statistical processing of signal-noise complex. The step of adapting four channel receivers to dynamically changing conditions of transmitting information may include determining the composition of the signal-noise mixture, determining the phase characteristics of the communication channel, estimating the channel transmission rate, and obtaining QoS information. In addition, adaptation often implies the use of a logical channel control loop, which entails the need for complex feedback procedures. Software-defined radio systems are radio and telecommunication systems that can be tuned to an arbitrary frequency band and receive various types of modulated signal, consisting of programmable equipment with program control. SDR performs a significant part of digital signal processing on a conventional personal computer, signal processor or FPGA. In such systems and complexes, the parameters are changed by software configuration. The article considers the implementation of DDS for heterodyning an intermediate frequency signal on the FPGA basis for four channel receiver 1288хк1т (mf-01), which allows you to work with both narrow-band and wide-band communication channels (with simultaneous operation of 4 channels, the band can be expanded) and can be used in modern telecommunication communication systems.
Combustion optimization in gas burners of reverberatory furnaces during the melting of nickel alloys
Authors: Quiroz Cabascango V E , Bazhin V Yu
Published: January 2021

In recent years, due to climate change environmental sustainability programs have been created that require the search for alternatives to reduce air emissions and reduce fuel consumption. The combustion industry is looking for an effective solution to increase the life cycle of its equipment and improve combustion efficiency without neglecting safety or savings. The efficiency of the medium pressure natural gas burners associated with chemical energy, which is converted into heat, that is, the hotter the gaseous products of combustion, the more efficient the burner. The work analyzes the combustion process and their chemical reactions; combustion products obtained in accordance with various conditions; combustion characteristics and factors that influence; and measurement methods needed to optimize combustion and their equipment. In the metallurgical production of nickel, optimization of the burners is very important due to the high temperature used in the reverberatory furnace. That is, the use of a large excess of air would be unfavorably energetic, and the use of a very low excess would result in small intimate mixtures of air and fuel, followed by the release of unreacted reagents and the formation of toxic gases arising at high temperatures. For this reason, the results of this work are an important source of information. The innovation is to automate the use of non-invasive sensors to control the combustion process. The sensors play a fundamental role in the industry, because the information they provide supports the enhanced use of data in the enterprise, increase productivity, efficiency and safety.
Study of dynamic properties of measuring equipment at the design stage
Authors: Sytko I I , Makhov V E
Published: January 2021

The modeling of measuring tools was carried out based on modern computer technologies in VisSim and Mathcad software. The transfer function of a measuring instrument in a closed state with negative feedback is determined. The range of changes in the feedback coefficient at which the dynamic system is stable is determined. The optimal feedback coefficient is determined by the criterion of the transition process minimum duration. The quality indicators of the measuring instrument are determined by the transition function: the time of setting (regulation), over-regulation, the number of fluctuations and the degree of attenuation. The transfer function of the measuring instrument is determined by error. The error rates for steady state position, speed and acceleration are obtained by decomposing the Taylor series of the transfer function by mistake in the Mathcad environment, using the series function. The stability reserves in amplitude and phase are determined before and after introduction of corrective links to the structure of the measuring instrument. The sequential regulator corrective link was synthesized according to the criterion – minimization of stabilization time. The serial controller parameters were calculated in Mathcad by gain coefficient interactive selection and time constant, with the ability to control its parameters by logarithmic frequency characteristics, as well as by static and dynamic properties in transient and steady-state modes. The dynamic safety is determined when one of the measuring tool parameters deviates from the nominal value.
Development of PLIC-based time synchronization device
Authors: Tynchenko V S , Kukartsev V V , Cherepanov A I , Petrenko V E , Dzhioeva N N
Published: January 2021

The article discusses a method of receiving and processing signals using a programmable logic integrated circuit in order to reduce the cost of time synchronization equipment. These actions are considered by the example of the «Beta» time signal. A method for receiving and processing a signal is described, based on the given structural diagram of the project. The installation was assembled and an experiment was conducted in accordance with the described parameters. The data obtained during the experiment in the form of graphs (spectral analysis of the signal, decoding of the Morse code and the information structure of the signal) are also presented. According to the results of the experiment, it is clear that the received signal from the “Beta” exact time service radio transmitter was received and processed without loss, as evidenced by the spectral analysis, as well as further decoding of the signal. The device fully complies with the set conditions and can be used in banking, metrology, as well as mobile operators, which will significantly reduce their costs. The assembled installation can be used in banking, metrology, and also by mobile operators, which will significantly reduce their time synchronization costs.
Development of methods for determining the density of low-melting metals
Authors: Dadashev R Kh , Kutuev R A
Published: January 2021

Features of the formation and development of scientific research in the laboratory of physics of interfacial phenomena in ChISU named after L. N. Tolstoy in the 1970-1980s of the last century are considered in this paper. Particular attention is paid to the development and improvement of various methods for measuring the density of liquid metals and alloys. We determined the contribution of ChSU scientists in the study of metals and alloys properties and gave a scientific assessment of the obtained results. The development of methods and techniques for measuring the density of liquid metals and alloys went in two directions. Primarily, we took significant steps towards improving the accuracy of density measurements. The instruments were designed in which the accuracy of measuring density and, in particular, the temperature coefficient of density was significantly increased. Foremost, this concerns advanced pycnometers and areometers designed in ChSU laboratories. The instruments received inventor’s certificates, and they were awarded the bronze medal of the Exhibition of Achievements of National Economy in 1977. The second direction improving the measuring technique of the metal properties is characterized by instrument designing for the joint measurement of physico-chemical properties in the same thermal vacuum conditions. Both areometers and pycnometers were used to determine density in these instruments.
Steady tangential control jet for improving the effectiveness of a rudder under one-engine inoperative condition
Authors: Leelaburanathanakul P , Virangkur V , Wangsiripaisarn T , Pitakarnnop J , Bunyajitradulya A
Published: January 2021

The aim of the research is to numerically investigate the use of a steady tangential control jet (CJ) at the hinge of the vertical stabilizer as an active flow control (AFC) technique to improve the effectiveness of a rudder on a subsonic aircraft during one-engine inoperative (OEI) condition by keeping the flow attached to the control surface. The goals are in two folds: firstly to investigate the effects of CJ parameters, specifically the jet-to-freestream velocity ratio (rV
) and the jet slot height ratio (rH
), on the vertical stabilizer performance, and secondly to find the optimum CJ condition that yields the improved and optimal performance. In this regard, the optimal condition of the CJ is prescribed as the condition that gives the maximum side force to drag ratio under the requirements that the required minimum trim side force can be achieved and there is an improvement in control surface margin for yawing motion. The investigation is carried out through computational fluid dynamics (CFD) using the Spalart-Allmaras turbulent model. Under the optimal CJ condition, its implementation can provide the required minimum rudder side force coefficient (Cy, trim
) of 1.19 at a rudder drag coefficient (Cd
) of 0.0013, a decrease in drag coefficient of 95% over the baseline case of plain flap without CJ. In addition, there is an improvement in rudder margin with the maximum side force coefficient increase by 42%, and the corresponding drag force coefficient decrease by 25% for the aircraft to yaw in a direction of the still-active engine.
Determination of Strong Factor in Bird Strike Analysis using Taguchi`s method for Aircraft Manufacturing guide
Authors: Mathaiyan Vijayakumar , Vijayanandh R. , Jung Dong Won
Published: January 2021

Bird strike analysis is of great importance because of the loss it can create. Since there are many factors which influences the level of damage, the computational cost for determining the strong factor is high. Usage of the optimization techniques will give the significant reduction of computational cost. Taguchi method is used to find out the strong factors for a detailed study of bird strike effects on the Aircrafts. This can help the engineers to manufacture the structure free from or have relatively less damage because of the bird strike.
Honeycomb structures manufactured by a new method and its failure analysis
Authors: Wang Lijun , Saito Kazuya
Published: January 2021

Nowadays, honeycomb sandwich panle is widely used in the field of aircraft and spacecraft, due to its light weight, high strength and good impact resistance. So the stability and buckling behavior of the structure are crucially important. In the present work, two type aluminum honeycomb sandwich panles were manufactured by a new manufacturing method (i.e. a press and folding process). To evaluate the structural failure of the panle, the three-point bending test was carried out, and found that the face sheets and the honeycomb core were splited open under a local load, but the panle has not been completely failure. In addition, the buckling behavior of the panle was implemented with finite element analysis (FEA).
Numerical Investigation of Fluid Flow, Characteristics of Thermal Performance and Enhancement of Heat Transfer of Corrugated Pipes with Various Configurations
Authors: Al-Obaidi Ahmed Ramadhan , Alhamid Jassim
Published: January 2021

The flow characteristics pattern and heat performance improvement have been analysed by applying the computational method in 3D corrugated configuration tubes. Configuration were carried out with varying geometrical parameters, counting various ring corrugated angle over a tube at several Re range between 4000 and 12000. Computational outcomes in this investigation were validated with available experimental data. Outcomes noted that there was a significant alteration in the behavior of flow structure hence an important rise in pressure losses and enhancement in thermal performance due to using corrugated configurations when compared with the normal plane pipe. By utilizing the latter tube under varying parameters, it produces more turbulence flows, separation, mixing, and more distribution in the boundary flow layer, hence enhancing the thermal flow performance. Furthermore, pressure and Nu were augmented when corrugated configurations rise. Besides, these configuration parameters have a significant impact on the value of overall heat performance. Then the higher value was about larger than 1.65. Computational calculations can provide good results on fluid structure inside the pipe and heat transfer augmentation.
Experimental Investigation of Forced Convective Heat Transfer in Circular Pipe with Wire Mesh Porous Media
Authors: Chanmak P , Krittacom B , Waramit P , Peamsuwan R
Published: January 2021

This experimentation aims to study Nusselt number (Nu) and Friction factor (f) deriving from the forced flow of fluid inside a circular pipe under a uniform heat flux condition. Porous media used in this study is made of stainless-steel wire mesh 304 which has the number of pores per inch (PPI) of 8. Reynolds number (Re) ranges from 3000 – 15000. Distance between two plates of wire mesh (p), ranges from 10-50 mm. The results of the experiment indicate that the Nu figure tends to be higher when there is a rise in Re and a decrease in length of p, resulting in an increase in mass of material. The increasing mass of material enables it to store a large quantity of energy from hot air causing heat to be transferred toward the pipe wall in a higher rate. The value f tends to decline when the Re and p grow up. This phenomenon rather conforms to the general principles of nature, namely that a barrier against the flow will lead to a higher friction factor (f). The Performance Evaluation Criteria (PEC), recorded across the whole Reynolds number range, reaches a maximum where the p is 40 mm since the ratio of Nu to f is the most appropriate figure.
Numerical Analysis of Microstructure Development during Laser Welding Nickel-based Single-crystal Superalloy Part IV: Welding Conditions Optimization
Authors: Gao Zhiguo
Published: January 2021

The thermal-metallurgical modeling of columnar/equiaxed transition(CET), multicomponent dendrite growth and nonequilibrium solidification behavior was further developed during single-crystal superalloy weld pool solidification over a wide range of laser welding conditions (laser power, welding speed and welding configuration). It facilitates the unprecedent understanding of the effect of welding conditions on overall stray grain formation, dendrite trunk spacing and solidification temperature range throughout the weld pool. In order to eliminate the solidification cracking through microstructure control, it is imperative to optimize the welding conditions for successful defect-free laser welding. Crystallographic orientation of dendrite growth plays an important role than heat input in microstructure development and solidification cracking susceptibility. Optimum low heat inputs (low laser power and high welding speed) of solidification condition simultaneously prevent stray grain formation, refine dendrite size and mitigate the solidification temperature range to improve the weldability and weld integrity and vice versa. Nonequilibrium solidification behavior of the weld pool suppresses the solidification temperature range and dendrite size, and improves the solidification cracking resistance. The overall stray grain formation, dendrite trunk spacing and solidification temperature range in (001) and [100] welding configuration are beneficially reduced than that of in (001) and [110] welding configuration regardless of heat input. The theoretical predictions agree well with the experiment results. Moreover, this promising model is also available to other single-crystal superalloys with similar metallurgical properties during laser welding or laser cladding.
Expansion of genetic and morphological approach to synthesis of principles of new clamping device for machine-tools
Authors: El-Dahabi Farouk , Kuznetsov Yuri , Abou-El-Hossein Khaled , Abbas Abdalla , Hweju Zvikomborero
Published: January 2021

This paper describes the use of a genetic and morphological approach employed in the development of a near structural synthesis of a machine-tool clamping cartridges having a mechanism based on the principles of tangential clamp. The study focuses on the design of device capable of holding a number of workpieces having cylindrical and flat shapes at the same time during metal cutting operation. The study reveals that the use of tangential principal clamping may open up new capabilities for the development of workholding devices that can be used to position and clamp few workpieces simultaneously.
Efficiency assessment of ANFIS in surface topology prediction in diamond turning of RSA443 optical aluminum using Small Datasets
Authors: Hweju Z. , Abou-El-Hossein K.
Published: January 2021

This paper presents an assessment of the efficiency of the ANFIS model in surface topology prediction of RSA 443 optical aluminium using small datasets. The experiments are designed and conducted based on the Taguchi L9 orthogonal array. The single point diamond turning procedure has been carried out on Nanoform 250 Precision CNC machine. Cutting speed, feed rate and depth of cut together with acoustic emission signal root mean square, dominant frequency and peak rate are the ANFIS model input parameters. The function that gave the best results was the sigmoidal membership function, hence it is used in this paper. To evaluate model performance, the measured surface roughness results are compared to ANFIS predicted results based on the Mean Absolute Percentage Error (MAPE) and prediction accuracy. The MAPE values show that the ANFIS prediction accuracy of surface topology is 79.42%. This value is within the upper quartile range, indicating the high predicting accuracy of ANFIS even in the absence of enough training data. The model can be reliably utilized in surface roughness prediction using small datasets while its prediction accuracy can however be improved by using larger datasets.
Flooding Control Mechanism of Waterflooding Sweep Control Technology
Authors: Yinzhu Ye , Xiaodong Kang , Baoshan Guan , Xianjie Li , Zhe Yang , Ke Hu , Xingcai Wu , Peiwen Xiao , Shichao Li , Yang Liu
Published: January 2021

In view of the problems of high permeability, high water cut and high recovery in offshore heterogeneous oil fields, the system including cross-linked polymer gel and flexible microgel gel was prepared indoors, which was used in the experiments of classified combination of waterflooding sweep control technology. The SMG microscopic oil displacement experiment shows that after the SMG system is injected into the model, the speed of the displacement fluid in the large pores decreases and the speed of the small pores increases, thereby effectively improving the oil recovery in the small pores. The long core experiment with multiple pressure points proves that the driving method of that cross-linked polymer gel and flexible microgel gel are alternately injected into core, which can block the dominant channel step by step and start. Then the low permeability area was displaced and the displacement fluid continuously diverted in the core, thus maximizing the purpose of oil recovery. The classification and grading water flooding control technology method provides effective technical support for the optimization of process parameters of offshore oilfield.
The introduction and comparison of two techniques of fluid transport at the microscale
Authors: Jiang Kaiyue
Published: January 2021

With the development of human society, people’s level of science and technology is also improving. In the process of continuous exploration, people often find some new unknown areas. Although we are very unfamiliar with these uncharted areas, they can have a significant impact on our lives, such as the field of microfluidics. It can perform small tasks at the micro and nano level, reducing our resource consumption, reducing some of our risks, but increasing our safety and new application tools. The exploration and development of the field of microscopic fluids can bring great help to our lives, especially in medicine, and significantly increase our surgical success rate. This article is summarized by analyzing and comparing the academic research of many experts. In this era, the role of the microfluid field is still significant.
Modification and Properties of EVA Foamed Material with Hemp Stem Powder
Authors: Guo Yafei , Hao Xinmin , Liang Gaoyong
Published: January 2021

In this study, a certain amount of hemp stem powder was added into ethylene-vinyl acetate (EVA) copolymer foam system by molding, and the improvement of properties of composite foam system with different hemp stem powder content of 0-30% was studied. The results showed that hemp could decrease the hardness and density of the composite foam system, improve the resilience and compression deformation rate, and have excellent moisture absorption and quick drying properties and antibacterial properties. The results show that the foaming system with 10% - 20% hemp stem powder has the best comprehensive mechanical properties, which can be used in shoes.
Effect of multi-phase STF on the high-speed impact performance of shear-thickening fluid (STF)-impregnated Kevlar Composite Fabrics
Authors: Wang Fadong , An Chao , Jia Qingxiu
Published: January 2021

Shear thickening is a non-Newtonian flow behavior, characterized by an increase in viscosity with the applied shear rate. Due to this superior performance of shear thickening fluid (STF), it has received a great deal of attention in the field of armor protection. In this paper, the properties of nanoscale silica STF systems are modified by the addition of nanocellulose (CNF). The rheological properties of the prepared STFs were tested. Kevlar fabrics were immersed in multiphase STF solutions to make STF/fabric composites. The results showed that the addition of nanocellulose (CNF) enhanced the steady-state and dynamic aspects of the shear-thickening fluid. The rheological properties of the shear-thickening fluid were strongest when the content of nanocellulose added was 0.2%, and the single yarn extraction force of the Kevlar composite was much stronger than that of the pure Kevlar without STF. The CNF-modified STF enhances the impact resistance of the composite.
Preparation of functionalized graphene/thermal conductive polyurethane films
Authors: Luo Zuhuo , Yan Jie , Chen Danqing
Published: January 2021

Graphene/polymer composites have been widely used as thermal conductive materials in electronic equipment. However, the development of advanced graphene thermal conductive composites faces many problems, such as easy agglomeration, high interfacial thermal resistance and poor mechanical properties. In our work, new graphene-based polyurethane thermal conductive composites based on octadecylamine (ODA), graphene and thermoplastic polyurethane were prepared. The thermal conductivity(λ) of the composites reached 1.46W/(mK) with loading 20wt.%mRGO, which was increased by 326.02% compared with that of TPU.
Effect of sintering insulation time on the properties and microstructure of graphite-copper composite
Authors: Zou Haiping , Yu Xiaohong , Wu HongLiang
Published: January 2021

The copper powder and graphite powder were used as raw materials to fabricate the graphite-copper composite by low temperature cold pressure powder metallurgy sintering method. The powders were mixed by ultrasonic dispersion and mechanical ball grinding process. The effects of sintering insulation time on the properties and microstructure of graphite-copper composite were investigated. The result showed that the distribution of graphite on the copper matrix was uniformly and formed a good interface by using the ultrasonic dispersion and mechanical ball grinding process. When the sintering insulation time was raised from 3 hours to18 hours, the friction coefficient and wear rate were decreased in the initial stage (from 3 hours to 12 hours) meanwhile the Vickers hardness (HV0.5) reached its maximum value 61.9HV when the sintering insulation time was 12 hours. The SEM (scanning electron microscope) images indicated that the increased sintering insulation time was helpful to distribute the graphite phased in composite relatively homogeneous with the sintering insulation time within 12 hours. However, the properties of graphite-copper composite also showed a downward or stable trend with the sintering Insulation time increasing from 12 hours to 18 hours.
Study on the Modeling and tensile performance simulation of knitted fabric-based conductive line
Authors: ZHANG Chengkun , XIAO Yuan , Qian LI
Published: January 2021

Aiming at the problem of easy breakage and low tensile performance during the preparation of flexible conductive lines on the fabric surface, numerical simulation methods are used to establish a medium-scale three-dimensional (3D) model of the knitted fabric-based conductive line. The influence of the shape and width of the conductive line on the tensile properties is studied, and the deformation and fracture processes of knitted fabrics and conductive lines under different stretching directions (horizontal, vertical, and shear) are clarified. The results show that the optimal geometric shape of the conductive line is horseshoe shape, the width of the conductive line is inversely proportional to the tensile performance, the crack section of the conductive line is straight when stretched horizontally, and the cross-section of the crack is sawtooth when stretched vertically, the initial stage of the crack section during shear stretching is the same as that of horizontal stretching, and the later crack development is irregular.
Evaluation of dynamic mechanical and cytotoxic properties of electrospun poly (lactic acid)/cellulose nanocrystalline composite membranes
Authors: Wang Fadong , Zhou Mengjiao , Jia Qingxiu
Published: January 2021

In this paper, polylactic acid (PLA)/cellulose nanocrystalline (CNC) composite fiber membranes were prepared by electrospinning technique. The microstructure of the fiber membranes produced was all transformed from a smooth surface to a nanoporous surface by varying the CNC loading level. The influence of CNC content on the morphology, thermal dynamic properties, and cytotoxic properties of PLA/CNC composite nanofiber membranes was characterized. The results show that water molecules can enhance the hydrogen bonding networks between PLA and CNC. when the cellulose nanocrystal content is less than 10%, the composite membranes have good dynamic mechanical properties and no significant cytotoxic effect.