scholarly journals Empirical and Numerical Analysis of Conduction and Induction Charging of Droplets in a Three-Electrode System

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 469 ◽  
Author(s):  
Adam Pelesz ◽  
Tomasz Czapka
Keyword(s):  
Numerical Analysis ◽  
Experimental Studies ◽  
Electrode System ◽  
Numerical Calculations ◽  
Simplified Model ◽  
Induction Method ◽  
Research Findings ◽  
Parameter Values ◽  
Electrically Charged ◽  
Induction Charging

The charging process of water droplets in different electrification systems using empirical and numerical analysis is described. A simplified model based on capacitance distribution is proposed. The results of the experimental studies and numerical calculations enable comparison of the induction and conduction charging methods in terms of the droplet charging level, described by the Q/m parameter. Research findings indicate that the conduction method in a 3-electrode system is the most effective among all the considered methods. It has been also shown that the application of a 2-electrode system under certain conditions provides greater Q/m parameter values in comparison to the system with three electrodes using the induction method. The research results can be used to develop charging systems (e.g., nozzles) that produce streams with electrically charged liquid particles.

scholarly journals The Influence of Welding Heat Source Inclination on the Melted Zone Shape, Deformations and Stress State of Laser Welded T-Joints

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5303
Author(s):  
Zbigniew Saternus ◽  
Wiesława Piekarska ◽  
Marcin Kubiak ◽  
Tomasz Domański
Keyword(s):  
Stress State ◽  
Numerical Analysis ◽  
Heat Source ◽  
Source Parameters ◽  
Experimental Studies ◽  
Welding Process ◽  
Experimental Tests ◽  
Material Model ◽  
Numerical Calculations ◽  
Heating Source

The paper concerns the numerical analysis of the influence for three different of welding heat source inclinations on the weld pool shape and mechanical properties of the resulting joint. Numerical analysis is based on the experimental tests of single-side welding of two sheets made of X5CrNi18-10 stainless steel. The joint is made using a laser welding heat source. Experimental test was performed for one heating source inclination. As a part of the work metallographic tests are performed on which the quality of obtained joints are determined. Numerical calculations are executed in Abaqus FEA. The same geometrical model is assumed as in the experiment. Material model takes into account changing with temperature thermophysical properties of austenitic steel. Modeling of the motion of heating source is performed in additional subroutine. The welding source parameters are assumed in accordance with the welding process parameters. Numerical calculations were performed for three different inclinations of the source. One inclination is consistent with experimental studies. The performed numerical calculations allowed to determine the temperature field, shape of welding pool as well as deformations and stress state in welded joint. The obtained results are compared to results of the experiment.

scholarly journals Numerical analysis of stability of an axially-compressed i-beam rod subjected to constrained torsion

2020 ◽  
pp. 11-27
Author(s):  
Amirshokh Kh. Abdurakhmonov
Keyword(s):  
Numerical Analysis ◽  
Axial Force ◽  
Analytical Data ◽  
Practical Interest ◽  
Numerical Calculations ◽  
Analysis Method ◽  
Numerical Analysis Method ◽  
Open Section ◽  
Thin Walled ◽  
Analysis Of Stability

Introduction. Today thin-walled structures are widely used in the construction industry. The analysis of their rigidity, strength and stability is a relevant task which is of particular practical interest. The article addresses a method for the numerical analysis of stability of an axially-compressed i-beam rod subjected to the axial force and the bimoment. An axially compressed i-beam rod is the subject of the study. Materials and methods. Femap with NX Nastran were chosen as the analysis toolkit. Axially compressed cantilever steel rods having i-beam profiles and different flexibility values were analyzed under the action of the bimoment. The steel class is C245. Analytical data were applied within the framework of the Euler method and the standard method of analysis pursuant to Construction Regulations 16.13330 to determine the numerical analysis method. Results. The results of numerical calculations are presented in geometrically and physically nonlinear settings. The results of numerical calculations of thin-walled open-section rods, exposed to the axial force and the bimoment, are compared with the results of analytical calculations. Conclusions. Given the results of numerical calculations, obtained in geometrically and physically nonlinear settings, recommendations for the choice of a variable density FEM model are provided. The convergence of results is estimated for different diagrams describing the steel behavior. The bearing capacity of compressed cantilever rods, exposed to the bimoment, is estimated for the studied flexibility values beyond the elastic limit. A simplified diagram, describing the steel behaviour pursuant to Construction regulations 16.13330, governing the design of steel structures, is recommended to ensure the due regard for the elastoplastic behaviour of steel. The numerical analysis method, developed for axially-compressed rods, is to be applied to axially-compressed thin-walled open-section rods. National Research Moscow State University is planning to conduct a series of experiments to test the behaviour of axially-compressed i-beams exposed to the bimoment and the axial force. Cantilever i-beams 10B1 will be used in experimental testing.

scholarly journals Modeling of formation of carbon cluster groups in electric arc discharge plasma

2018 ◽  
Vol 80 (2) ◽  
pp. 108-113 ◽  
Author(s):  
A. N. Gavrilov
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Experimental Studies ◽  
Particle Method ◽  
Cost Effective ◽  
Carbon Cluster ◽  
Collision Integral ◽  
Numerical Calculations ◽  
Plasma Synthesis ◽  
Interelectrode Space

The problem of modeling complex resource-intensive processes of plasma synthesis of carbon nanostructures (CNS) on the basis of mathematical and numerical methods of solution, focused on the use of parallel and distributed computing for processing large amounts of data, allowing to investigate the relationship and characteristics of processes to obtain an effective, cost-effective method of synthesis of CNS (fullerenes, nanotubes), is an actual theoretical and practical problem. This article deals with the problem of mathematical modeling of motion and interaction of charged particles in a multicomponent plasma based on the Boltzmann equation for the synthesis of ONS by thermal sublimation of graphite. The derivation of the collision integral is presented allowing to perform a numerical solution of the Boltzmann - Maxwell equations system with respect to the arc synthesis of CNS. The high order of particles and the number of their interactions involved simultaneously in the process of synthesis of CNS requires significant costs of machine resources and time to perform numerical calculations on the constructed model. Application of the large particle method makes it possible to reduce the amount of computing and hardware requirements without affecting the accuracy of numerical calculations. The use of parallel computing technology on the CPU and GPU with the use of Nvidia CUDA technology allows you to organize all the General-purpose calculations for the developed model based on the graphics processor of the personal computer graphics card, without the use of supercomputers or computing clusters. The results of experimental studies and numerical calculations confirming the adequacy of the developed model are presented. Obtained quantitative characteristics of the total pairwise interactions between the carbon particles and interactions with the formation of clusters of carbon with various types of ties in the plasma of the interelectrode space which are the basis of the synthesized nanostructures. The formation of carbon clusters occurs in the entire interelectrode space of the plasma with different intensity and depends on the process parameters.

scholarly journals ‘The awesome power of yeast’ in Alzheimer’s disease research

2021 ◽  
Vol 42 (3) ◽  
pp. 130
Author(s):  
Sudip Dhakal
Keyword(s):  
Simple Model ◽  
Animal Models ◽  
Human Brain ◽  
Human Cell ◽  
Cell Biology ◽  
Experimental Studies ◽  
Disease Models ◽  
Disease Research ◽  
Research Findings ◽  
Technological Platforms

The difficulties in performing experimental studies related to diseases of the human brain have fostered a range of disease models from highly expensive and complex animal models to simple, robust, unicellular yeast models. Yeast models have been used in numerous studies to understand Alzheimer’s disease (AD) pathogenesis and to search for drugs targeting AD. Thanks to the conservation of fundamental eukaryotic processes including ageing and the availability of appropriate technological platforms, budding yeast are a simple model eukaryote to assist with understanding human cell biology, offering a platform to study human diseases. This article aims to provide insights from yeast models on the contributions of amyloid beta, a causative agent in AD, and recent research findings on AD chemoprevention.

scholarly journals Smart but Evil? Student-Teachers’ Perception of Educational Researchers’ Epistemic Trustworthiness

AERA Open ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 233285841986815
Author(s):  
Samuel Merk ◽  
Tom Rosman
Keyword(s):  
Preservice Teachers ◽  
Student Teachers ◽  
Exploratory Study ◽  
Classroom Practice ◽  
Scientific Evidence ◽  
Experimental Studies ◽  
Epistemic Beliefs ◽  
Research Results ◽  
Research Findings ◽  
Integrate Research

In-service and preservice teachers are increasingly required to integrate research results into their classroom practice. However, due to their limited methodological background knowledge, they often cannot evaluate scientific evidence firsthand and instead must trust the sources on which they rely. In two experimental studies, we investigated the amount of this so-called epistemic trustworthiness (dimensions expertise, integrity, and benevolence) that student-teachers ascribe to the authors of texts who present classical research findings (e.g., learning with worked-out examples) that allegedly were written by a practitioner, an expert, or a scientist. Results from the first exploratory study suggest that student-teachers view scientists as “smart but evil,” since they rate them as having substantially more expertise than practitioners, while also being less benevolent and lacking in integrity. Moreover, results from the exploratory study suggest that evaluativistic epistemic beliefs (beliefs about the nature of knowledge) predict epistemic trustworthiness. A preregistered conceptual replication study (Study 2) provided more evidence for the “smart but evil” stereotype. Further directions of research as well as implications for practice are discussed.

scholarly journals Overall buckling analysis on different formed circular steel tubular columns under axial compression

2019 ◽  
Vol 277 ◽  
pp. 03017
Author(s):  
Xi Feng Yan
Keyword(s):  
Numerical Analysis ◽  
Axial Compression ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Element Model ◽  
Welded Steel ◽  
Eurocode 3 ◽  
Column Design ◽  
Hot Rolled ◽  
Overall Buckling

This paper presents a numerical finite element model (FEM) investigation on the overall buckling behaviour of hot-rolled (HR), submerged arc welded (SAW) and high-frequency welded (HFW) steel circular columns under axial compression. Three dimensional FEM of circular hollow sections were developed using shell elements considering material nonlinearities, geometric imperfections and residual stress. The established FEM was used to simulate experimental studies conducted by past researchers. Good agreement has been found between numerical analysis and past researchers results, which has validated the reasonability of the FEM to carry out further investigation. Based on the validated FEM, numerical analysis incorporating 180 numerical generated HR, SAW and HFW steel circular columns with various section sizes and slenderness were carried out. The numerical analysis results were compared with the existing column design curves in Chinese, European and American codes. The numerical results showed that the design resistances for hot-rolled and welded steel circular columns calculated based on design curve a in both GB 50017-2003 and Eurocode 3 and the design formula in ANSI/AISC 360-2016 should be accepted. In addition, to further improve the design efficiency, new column design curves for hot-rolled and welded steel circular columns were recommended based on the expressions in GB 50017-2003 and Eurocode 3.

scholarly journals Numerical Analysis of Diaphragm Wall Model Executed in Poznań Clay Formation Applying Selected Fem Codes

2016 ◽  
Vol 62 (3) ◽  
pp. 207-224 ◽  
Author(s):  
M. Superczyńska ◽  
K. Józefiak ◽  
A. Zbiciak
Keyword(s):  
Numerical Analysis ◽  
Constitutive Models ◽  
Experimental Tests ◽  
Numerical Calculations ◽  
Diaphragm Wall ◽  
Construction Site ◽  
Wall Model ◽  
City Area ◽  
Clay Formation ◽  
Horizontal Displacements

Abstract The paper presents results of numerical calculations of a diaphragm wall model executed in Poznań clay formation. Two selected FEM codes were applied, Plaxis and Abaqus. Geological description of Poznań clay formation in Poland as well as geotechnical conditions on construction site in Warsaw city area were presented. The constitutive models of clay implemented both in Plaxis and Abaqus were discussed. The parameters of the Poznań clay constitutive models were assumed based on authors’ experimental tests. The results of numerical analysis were compared taking into account the measured values of horizontal displacements.

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