Resistive torque in permanent magnet couplings operating through a conductive wall

2017 ◽  
Vol 36 (4) ◽  
pp. 1120-1133
Author(s):  
Thomas Rezek Matsumoto ◽  
Ivan Chabu
Keyword(s):  
Permanent Magnet ◽  
Design Methodology ◽  
Analytical Approach ◽  
Eddy Currents ◽  
Experiment Data ◽  
Content Type ◽  
Analytical Formulation ◽  
Resistive Torque ◽  
Torque Transmission ◽  
Coupling Performance

Purpose The purpose of this paper is to propose an analytical approach to determine the resistive torque caused by a conductive wall between the rotors of axial permanent magnet couplings. In this configuration, relative motion between the coupling rotors and the wall generates a resistive torque that is a consequence of the induced eddy currents in this barrier. Therefore, such induced resistive torque implies a reduction in the permanent magnet coupling performance, that is, its torque transmission capacity. Design/methodology/approach The developed resistive torque analytical formulation was based on eddy-current brakes of previous studies. To validate the proposed method, tests were conducted in a prototype and results were compared with analytical ones. Findings The analytical method showed a good correlation with the experiment data. Furthermore, a major degradation of the coupling capability to transmit torque was found because of the conductive wall presence, enhancing the importance of predicting such phenomenon when designing these devices. Originality/value A novel direct assessment of the resistive torque while in motion is presented in this paper. These measurements were of great importance to accurately compare the analytical and experimental data.

The role of Muslim women in managing the family during crisis: corona pandemic as a model

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Haifa F. Fawaris
Keyword(s):  
Significant Role ◽  
Design Methodology ◽  
Analytical Approach ◽  
Muslim Women ◽  
Muslim Woman ◽  
Content Type ◽  
Study Results ◽  
The Family ◽  
Mental Characteristics

Purpose This study aims to clarify the role of Muslim women in managing their families during the corona pandemic crisis. To achieve this aim, the researcher applied the descriptive and analytical approach. Design/methodology/approach The Muslim women have had a prominent position consistent with the physical, psychological and mental characteristics that Allah has created them. This status is shown by: affirming their rights in all areas of life; affirming everything that preserved the dignity of women before Islam; and correcting all the conditions that detracted their dignity before the advent of Islam and making them responsible in public Islamic life on the level of: preserving Islam, spreading the Islamic call and achieving the civilization advancement of the Muslim nation. Findings The study resulted in many significant results. The most important one of the study results was that, in the context of woman rights and responsibilities she had assumed in Islam, the Muslim woman had a prominent position in Islam. In addition, the mother in the Muslim family had a significant role as a leader, who is capable of managing the family in corona crisis and supporting family members in all aspects such as faith, intellectual endeavors, psychological, social and health, so that they are real leaders. Originality/value The study recommends carrying out educational studies that identify and show the role of institutions other than the family in managing emergency crises.

Effect of torque ratio on speed regulating start

2018 ◽  
Vol 70 (9) ◽  
pp. 1657-1663
Author(s):  
Qingrui Meng ◽  
Zhao Chenghao ◽  
Tian Zuzhi
Keyword(s):  
Film Thickness ◽  
Theoretical Basis ◽  
Design Methodology ◽  
Load Capacity ◽  
Load Torque ◽  
Content Type ◽  
Oil Film ◽  
Torque Transmission ◽  
Drive Speed ◽  
Starting Process

Purpose Friction pairs of the hydro-viscous drive speed regulating start device should be designed based on the rated torque. To obtain design basis of the rated torque of the hydro-viscous drive speed regulating start device, studies on effect of torque ratio (a ratio of the load torque to the rated torque) on speed regulating start were carried out theoretically and experimentally. Design/methodology/approach Under different torque ratio, the modified Reynolds, the thermal energy and the viscosity-temperature equations were solved simultaneously by using finite element method to reveal variation laws of the oil film load capacity and torque transmission during the starting process. Then, speed regulating start experiments were carried out to study the following performance of the output speed. Findings The results show that oil film thickness decreases with the increase of the torque ratio; when oil film thickness is less than 0.05 mm, oil film temperature increases rapidly with the decrease of oil film thickness, which eventually deteriorates performance of the speed regulating start; when the torque ratio decreases to about 0.3, output speed shows a better following performance. Originality/value It indicates that, to acquire a better speed regulating start, the rated torque of the hydro-viscous drive speed regulating start device should not be less than three times of the load torque. Achievements of this work provide theoretical basis for optimal design of the friction pairs of the hydro-viscous drive speed regulating start device.

An analytical approach for analysis and optimization of formation of field-effect heterotransistors

2016 ◽  
Vol 12 (4) ◽  
pp. 578-604 ◽  
Author(s):  
Evgeny L. Pankratov ◽  
Elena A. Bulaeva
Keyword(s):  
Heat Transport ◽  
Technological Process ◽  
Multilayer Structure ◽  
Field Effect ◽  
Design Methodology ◽  
Analytical Approach ◽  
Charge Carriers ◽  
Cross Linking ◽  
Content Type ◽  
Time Parameters

Purpose The purpose of this paper is to analyze and optimize the formation of field-effect heterotransistors using analytical approach. The approach makes it possible to analyze mass and heat transport in a multilayer structure without cross-linking of solutions on interfaces between layers of the multilayer structure. The optimization makes it possible to decrease dimensions of the heterotransistors and to increase speed of transport of charge carriers during functioning of the transistors. Design/methodology/approach The authors introduce an analytical approach for analysis of mass and heat transport, which makes it possible to take into account at one time varying in space and time parameters of the transports (diffusion coefficient, heat conduction coefficient, etc.) and nonlinearity of processes. The approach enables analysis of mass and heat transport in a multilayer structure without cross-linking of solutions on interfaces between layers of the multilayer structure and optimises the technological process. The optimization means it is possible to decrease dimensions of field-effect heterotransistors. Findings In this paper the authors introduce an approach to manufacture a field-effect heterotransistor with inhomogeneous doping of channel. Some recommendations to optimize technological process to manufacture more compact distribution of concentration of dopant have been formulated. Originality/value The results are original and the paper provides an approach to the manufacture of a field-effect heterotransistor.

Impact of plasticity generated by Rayleigh waves on the residual stress behavior of structural components subjected to laser peening

2015 ◽  
Vol 6 (1) ◽  
pp. 107-123 ◽  
Author(s):  
Anoop Vasu ◽  
Ramana V. Grandhi
Keyword(s):  
Residual Stress ◽  
Rayleigh Waves ◽  
Design Methodology ◽  
Laser Peening ◽  
Structural Components ◽  
Wave Mechanics ◽  
Content Type ◽  
Analytical Formulation ◽  
Increasing Trend ◽  
The Impact

Purpose – The impact of laser peening on curved geometries is not fully comprehended. The purpose of this paper is to explain the action of laser peening on curved components (concave and convex shapes for cylindrical and spherical geometries) by means of shock wave mechanics. Design/methodology/approach – An analytical formulation is derived based on the plasticity incurred inside the material and the results are compared with the prediction by numerical simulation. Findings – A near-linear relationship is observed between curvature and compressive residual stress; an increasing trend was observed for concave models and a decreasing trend was observed for convex models. The consistency in the analytical formulation with the simulation model indicates the behavior of laser peening for curved geometries. Originality/value – The differences observed in the residual stresses for spherical and cylindrical geometries are primarily due to the effect of Rayleigh waves. This paper illustrates the importance of understanding the physics behind laser peening of curved geometries.

Characterization of rotor losses in permanent magnet machines

2020 ◽  
Vol 39 (5) ◽  
pp. 1215-1226
Author(s):  
Antomne Caunes ◽  
Noureddine Takorabet ◽  
Sisuda Chaithongsuk ◽  
Laurent Duranton
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
High Speed ◽  
Permanent Magnets ◽  
Eddy Currents ◽  
Computing Time ◽  
Element Model ◽  
Permanent Magnet Machines ◽  
Content Type ◽  
Rotor Losses

Purpose The purpose of this paper is to present a synthesis of the analysis and modeling of the rotor losses in high speed permanent magnets motors. Design/methodology/approach Three types of losses are as a result of eddy currents in the conductive parts of the rotor. The analysis includes their characterization and the setup of a numerical model using finite element method. The adopted methodology is based on the separation of the losses which allows a better understanding of the physical phenomena. Each type of losses will be modeled and computed separately. Findings It is possible to make a precise estimate of the different losses in the rotor while keeping a relatively short computing time. Research limitations/implications The analysis is applied on a high-speed permanent magnet motor for avionic application. The model is validated with the commercial finite element model (FEM) software Flux2D. Originality/value The developed model allows an important save in terms of CPU-time compared to commercial FEM software while staying accurate. The separation of each losses and their sources is important for motor engineers and was requested for them to improve the designs more easily.

Selective harmonic elimination in direct torque controlled permanent magnet synchronous motor drive

2019 ◽  
Vol 38 (1) ◽  
pp. 153-166
Author(s):  
Vahid Asadzadeh ◽  
Ali Dastfan ◽  
Ahmad Darabi
Keyword(s):  
Permanent Magnet ◽  
Design Methodology ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Modulation Method ◽  
Motor Drive ◽  
Frequency Spectra ◽  
Content Type ◽  
Harmonic Elimination ◽  
Selective Harmonic Elimination

Purpose The purpose of this paper is to describe a new method for selective harmonic elimination in a two-level three-phase inverter-fed direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drive to suppress unwanted resonant frequencies. Design/methodology/approach The design methodology is based on random space vector pulse-width modulation (RSVPWM) of PMSM drives. MATLAB simulations support the validity of suggested structure. Findings The simulation results of the proposed algorithm exhibit the development of a proper gap at the selected frequency in the frequency spectra of the motor input currents and voltages as well as lowering the ripples in the PMSM electromagnetic torque, stator current and flux linkage responses in compared with traditional DTC. Originality/value The proposed algorithm is a revised form of the RSVPWM technique used in a closed-loop structure along with a sliding mode speed controller which is capable to deal with nonlinear motor loads in an online manner. This study can be beneficial for the designers of AC motor drive system who attempt to find a modulation method that can create a selective gap in the power spectrum density of the motor input voltages and currents, therefore, promote an acoustically pleasant drive or alleviate unwanted motor vibrations.

Design and analysis of PMLSM with SIN + 3rd shaping mover

2018 ◽  
Vol 37 (6) ◽  
pp. 2158-2175 ◽  
Author(s):  
Lufeng Zhang ◽  
Kai Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Permanent Magnet ◽  
Design Methodology ◽  
Thrust Force ◽  
Synchronous Machines ◽  
Content Type ◽  
Third Harmonic ◽  
Pitch Ratio ◽  
Sinusoidal Currents

Purpose The purpose of this paper is to investigate the electromagnetic performances of the permanent magnet linear synchronous machines (PMLSM) with sine and third harmonic (SIN + 3rd) shaping mover in comparison with the PMLSM with sine (SIN) shaping mover and conventional shaping mover. Design/methodology/approach The optimal amplitude of the injected third harmonic to re-shape the SIN + 3rd shaping permanent magnet (PM) for maximizing the thrust force is analytically derived and confirmed by finite element method (FEM). Furthermore, the PM edge thickness, the pole arc to pole pitch ratio and the tooth to slot ratio are optimized. It is found that the optimal amplitude of the injected third harmonic is one-sixth of the fundamental one, the optimal PM edge thickness, the pole arc to pole pitch ratio and the tooth to slot ratio are 0, 0.85 and 0.5 mm, respectively. In addition, the electromagnetic performances are analyzed and quantitatively compared for the PMLSM with SIN + 3rd shaping mover, SIN shaping mover and conventional shaping mover. Findings The average thrust force and efficiency of the PMLSM with SIN + 3rd shaping mover are improved significantly, while the thrust ripple is not increased, comparing to those of the PMLSM with SIN shaping mover. Meanwhile, the thrust ripple is lower than that of the conventional shaping mover. Research limitations/implications The purely sinusoidal currents are applied in this analysis and the influences of harmonics in the current on electromagnetic performances are not considered. Originality/value This paper presents a PMLSM with SIN + 3rd shaping mover to improve the thrust force and efficiency without increasing the thrust ripple, considering the effects of the amplitude of the injected third harmonic to re-shape the SIN + 3rd shaping PM, the PM edge thickness, the pole arc to pole pitch ratio and the tooth to slot ratio.

Russian agon and the quest for theoretical sociology

foresight ◽  
2017 ◽  
Vol 19 (4) ◽  
pp. 376-385
Author(s):  
Sergey B. Kulikov
Keyword(s):  
Transition Economies ◽  
Design Methodology ◽  
Analytical Approach ◽  
Propositional Attitudes ◽  
Content Type ◽  
The Past ◽  
Knowledge Based ◽  
Epistemological Analysis ◽  
Practical Implications ◽  
Theoretical Developments

Purpose The purpose of this paper is to represent an epistemological analysis of Russian sociological scholarship. Design/methodology/approach The analytical approach that allows reducing the particular representations within the sum of propositions is the methodological base of the paper. Clearing of propositional attitudes explains the basic communications in a thought of researchers. The circle of grounds available to achievement of intuitively noticed purposes defines the preferences of researchers in general. Findings The author proves that the theoretical developments in the Russian sociology are possible as a derivative from the development of questions, which are raised nowadays in worldwide science, but possible in a view of original development of questions, which were raised in worldwide science in the past. Research limitations/implications The Russian sociology represents a part of the European humanities, which is based on the various forms of theoretical combat or agonality. Practical implications The author shows the ways out of the theoretical combat or agonality. Social implications The research clarifies the perspectives for increasing of the knowledge-based society in Russia. The author analyzes the concept of Russia as a paradigmatic society, particularly in the context of transition economies. Originality/value In general, the author concludes that the pro-argument with respect to theoretical developments is weaker than the contra-argument with respect to theoretical developments. This paper has revealed the model within which extreme positions can be reconciled.

scholarly journals Covid-19 protocols: assessing construction site workers compliance

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Michael Ayodele Olukolajo ◽  
Abiodun Kolawole Oyetunji ◽  
Ifeoluwa Benjamin Oluleye
Keyword(s):  
Research Method ◽  
Design Methodology ◽  
Analytical Approach ◽  
Preventive Measures ◽  
Construction Site ◽  
Construction Sites ◽  
Protective Measures ◽  
Content Type ◽  
Contact Precautions ◽  
Structured Questionnaire

Purpose This paper aims to investigate construction site workers’ compliance with various coronavirus (Covid-19) protocols while working on construction sites. Design/methodology/approach This survey was conducted at the end of the imposed lockdown following Nigeria’s upsurge of the Covid-19 pandemic. The survey research method was adopted for the study using a structured questionnaire administered to 246 construction site workers under strict Covid-19 preventive measures. The data was complemented through personal observations of the study site activities. The results were analysed using frequency tables and a factor analytical approach. Findings The preventive measures in place on construction sites can be classified into personal protective measures, good etiquette/manners, contact precautions and prompt actions. Although the workers claimed to be aware of the Covid-19 pandemic, their disposition towards the preventive measures on construction sites is worrisome. Hence, their level of compliance with the protocols could mitigate the spread of the virus. Originality/value This paper fulfils an identified gap to study the need to promote public health by mitigating the global pandemic’s spread in areas where social distancing cannot be easily observed.

scholarly journals Digital transformation: why companies resist what they need for sustained performance

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Johan Magnusson ◽  
Viktor Elliot ◽  
Johan Hagberg
Keyword(s):  
Case Studies ◽  
Clinical Studies ◽  
Design Methodology ◽  
Analytical Approach ◽  
Digital Transformation ◽  
Content Type ◽  
Organizational Resistance ◽  
Sustained Performance ◽  
Combination Of Methods ◽  
Practical Implications

Purpose The purpose of this study is to contribute to firms’ capabilities of digital transformation through the identification of strategies for digital decoupling and recoupling. Design/methodology/approach This paper reports from multiple studies using a combination of methods such as case studies and clinical studies. The method of analysis involves the revisiting of vignettes from interactions with practitioners with the purpose of analyzing patterns in responses to digital transformation. Findings The findings consist of four strategies used by organizations and individuals in the decoupling of digital from their existing operations. Digital decoupling affords the organization the possibility of remaining largely unaffected by digital transformation. The authors also present four digital recoupling strategies that are used to succeed with digital transformation. Research limitations/implications This study is limited by the analytical approach of drawing from multiple previous studies. The research implications consist primarily of a contribution to a better understanding of why and how digital transformation is constrained. Practical implications The four strategies of digital decoupling can be used to identify behavior in organizations that limit digital transformation. The four strategies of digital recoupling can be used to instigate a more successful digital transformation. Originality/value According to the authors’ knowledge, this study is the first to identify digital decoupling strategies as a micro-foundation for organizational resistance to digital transformation.

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