Magnetization reduction by varying normal field in stacks of composite superconductors in an electrical motor

2020 ◽  
Vol 92 (2) ◽  
pp. 20902
Author(s):  
Anis Smara ◽  
Thomas Reis ◽  
Vicente Climente-Alarcon ◽  
Bartek A. Glowacki
Keyword(s):  
Conceptual Design ◽  
Magnetic Circuit ◽  
Electrical Machine ◽  
Experimental Measurements ◽  
Normal Field ◽  
Trapped Field ◽  
Composite Superconductors ◽  
Electrical Motors ◽  
Comparison Of The Results ◽  
Different Levels

Trapped field magnets of superconducting stacks could be an alternative to conventional magnets in electrical machine applications. A conceptual design of an electrical motor using these stacks was proposed in [1,2]. Superconducting stacks offer many advantages; however, they can be demagnetized when exposed to the varying field present in electrical motors during operation. This varying field can be generated by salient magnetic circuit or generated from the armature winding as harmonics. To study this demagnetization effect, we carried out an experiment on a superconducting stack in an electrical machine, exposing it to different levels of varying cross and normal fields. The experimental measurements recorded a demagnetization of the stack. In this work, the analyses of the reduction of magnetization of the superconducting stack by an alternating normal field and the comparison of the results with experimental measurements in the electrical motor are presented.

A Simple Approach to Characterize Finite Compressibility of Elastomers

2003 ◽  
Vol 76 (4) ◽  
pp. 912-922 ◽  
Author(s):  
Mark R. Gurvich ◽  
Thomas S. Fleischman
Keyword(s):  
Carbon Black ◽  
Bulk Modulus ◽  
Experimental Verification ◽  
Material Properties ◽  
Numerical Approach ◽  
Simple Approach ◽  
Experimental Measurements ◽  
Axially Loaded ◽  
Different Levels

Abstract A hybrid experimental-numerical approach is proposed for accurate dimensionless characterization of rubber finite compressibility. Rubber specimens in the form of bonded rubber disks are considered as elastomeric structures with unknown material properties. These properties are calculated by matching results of FEA with experimental measurements of radial deformations of the axially-loaded disks. The approach may be used for reliable characterization of Poisson's ratio, bulk modulus, or other characteristics of interest. Implementation of the approach is considered for two representative elastomeric compounds with different levels of carbon black. Good experimental verification of the approach is shown at different levels of loading. Moreover, the same parameters of finite compressibility are independently obtained using both compressive and tensile loads. Higher compressibility is observed for a compound with larger content of carbon black as expected.

A Comparison of Modern and Classical Experimental Methods of Mechanics in Strain Investigation

2014 ◽  
Vol 611 ◽  
pp. 501-505 ◽  
Author(s):  
Miroslav Pástor ◽  
Martin Hagara
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Method ◽  
Image Correlation ◽  
Deformation Analysis ◽  
Digital Image Correlation Method ◽  
Aluminum Sample ◽  
Correlation System ◽  
Comparison Of The Results ◽  
Different Levels

In this contribution a comparison of the results of deformation analysis performed in a classical way using strain gage and modern way, when a non-contact digital image correlation method was used, is described. Both methods were applied simultaneously for the investigation of the aluminum sample with stress concentrators loaded by tension, what prevented the investigation by different conditions. The contribution includes also the comparison of the results obtained using digital image correlation method by different levels of smoothing filters, which the software delivered together with correlation system contents.

scholarly journals Handgrip and functional mobility in elderly with different levels of physical activity

2014 ◽  
Vol 21 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Dayane de Oliveira Macedo ◽  
Letícia Mendes de Freitas ◽  
Marcos Eduardo Scheicher
Keyword(s):  
Physical Activity ◽  
Grip Strength ◽  
Elderly People ◽  
Functional Mobility ◽  
Timed Up And Go ◽  
Physically Active ◽  
Post Test ◽  
Kolmogorov Smirnov ◽  
Comparison Of The Results ◽  
Different Levels

The proportion of elderly people is growing worldwide and, with this, there is an increase of chronic-degenerative conditions such as impaired balance and falls. The physically active elderly tends to an improved response in muscle strength, flexibility and postural balance. The present study aimed to evaluate and compare the grip strength and mobility of elderly people with different levels of physical activity. The sample consisted of 44 elderly with 60 years or more, both sexes, divided in: 18 elderly practicing volleyball adapted (AVG), 13 elderly practicing some physical activity (AG) and 13 sedentary elderly (SG). Grip strength was assessed by a hydraulic dynamometer and mobility through the test "Timed Up and Go" (TUG). Data were evaluated using the Kolmogorov-Smirnov test, to check normality. The comparison of the results of the three groups was performed by ANOVA with Tukey post-test, with p<0.05. The results showed that grip strength (p=0.008) and mobility (p=0.003) were better to AVG when compared to the other groups. It is suggested that the sports practice implement the gains in functional mobility and strength when compared to purely non-specific exercise and inactivity.

scholarly journals Assessment of the Balanced Functioning of Hierarchical Socio-Economic Systems

2021 ◽  
Vol 20 (1) ◽  
pp. 84-109
Author(s):  
R. A. Zhukov ◽  
Keyword(s):  
Mutual Influence ◽  
Federal District ◽  
Economic Systems ◽  
The Sustainable Development ◽  
Central Federal District ◽  
Special Procedure ◽  
Comparison Of The Results ◽  
The Relationship ◽  
Different Levels ◽  
Integral Indicator

Balance is one of the properties of the system, and the problems associated with the assessment of balance, the choice of indicators, methods and tools that allow you to make informed management decisions in this area in the future are still open. The aim of the study is to develop and test a methodology for assessing the balance of the functioning of hierarchical socio-economic systems on the basis of the case of the regions of the Central Federal District of Russia. The hypothesis is that the proposed methodology can be effectively applied to study the balance of complex systems along with existing methods in the framework of a new theory of economic systems. The method consists in the formation of special indicators – the coefficient of harmony and the adjusted index of system balance, which allow us to assess the degree of balance of subsystems within the accepted space-time classification. The first of them takes into account the spread of generalized (integral) performance indicators that characterize the object, environment, process and project subsystems. The second one is the intensity of the relationships between them. The integral indicator is calculated by means of a special procedure for convolution of partial results (actual and normative). The norm is determined by a model of the relationship between performance and significant factor characteristics. The peculiarity of the proposed method is the possibility of its use at different levels of management. It also provides a reasonable comparison of the results of the functioning of various subsystems and elements by eliminating the influence of units of measurement and the scale effect; the mutual influence of the considered elements and subsystems is taken into account; the specific conditions of their operation are taken into account. The case of the regions of the Central Federal District is used to carry out a comparative analysis of the results of assessing the balance of subsystems using the volume of gross domestic product by region by type of economic activity for 2007-2018,. The conclusion is made about the possibility of using, along with the index of system balance, the coefficient of harmony. The practical results of the study can be used by government authorities to make decisions and develop measures aimed at ensuring the sustainable development of the regions of the Central Federal District.

scholarly journals Unified Models for Multiphase Coupled Inductors

2020 ◽  
Author(s):  
Minjie Chen
Keyword(s):  
Matrix Models ◽  
Magnetic Circuit ◽  
Experimental Measurements ◽  
Spice Simulation ◽  
Theoretical Derivation ◽  
Magnetic Structures ◽  
Coupled Inductors ◽  
Coupled Structures ◽  
Circuit Duality ◽  
Dual Models

<div> <div> <p>Circuit models for multiphase coupled inductors</p><p>are summarized, compared, and unified. Multiwinding magnetic structures are classified into parallel-coupled structures and series-coupled structures. For parallel-coupled structures used for multiphase inductors, the relationships between a) inductance matrix models, b) extended cantilever models, c) magnetic circuit models, d) multiwinding transformer models, e) gyrator-capacitor models, and f) inductance dual models are investigated and</p><p>discussed. These models represent identical physical relationships in the multiphase coupled inductors, but emphasize different physical aspects and offer distinct design insights. The circuit duality between the series coupled structure and the parallel coupled structure is revealed. Design equations linking these models are compared and unified. The models and design equations are verified through theoretical derivation, SPICE simulation, and experimental measurements.</p></div></div>

An Incidence Matrix Support for Conceptual Design Based on Port Ontology

2009 ◽  
Vol 419-420 ◽  
pp. 49-52 ◽  
Author(s):  
Dong Xing Cao ◽  
Zhan Wei Li ◽  
Hong Lai Li ◽  
Kai Cheng Qi
Keyword(s):  
Conceptual Design ◽  
Incidence Matrix ◽  
Product Information ◽  
Design Stage ◽  
Design Decision ◽  
Physical Domain ◽  
Levels Of Abstraction ◽  
Conceptual Design Stage ◽  
Different Levels

Existing conceptual design methods mainly focus on component modeling and representation, which makes them insufficient to help in the conceptual design stage. Port ontology, as an approach to formally expressing product design, has been effectively applied to concept description of a product. An incidence matrix support for product conceptual design based on port ontology is given in this paper. It formally represents and organizes product information in both functional ontology and physical domain in a hierarchy. Port compatibilities are used to map and link the two components. This makes it possible to build incidence matrix and decompose it into an independence matrix, and allow designers from different backgrounds with various interests to access the design ontology. A multilevel matrix is constructed to generate principle schemes of products at different levels of abstraction, which facilitates design decision-making through the whole conceptual design stage. A case study is also given to demonstrate the proposed approach.

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