Study of Non-Homogeneity of Magnetic Field Distribution in Single-Crystal Ni-Mn-Ga Magnetic Shape Memory Element in Actuators due to its Anisotropic Twinned Microstructure

Magnetic shape memory (MSM) alloys are relatively new and very promising “smart” materials which respond to magnetic fields and exhibit the shape memory effect at room temperature. Maximum strain varies from 6 to 12% of the MSM element’s length depending on its microstructure. The shape memory effect and magnetic field-induced reorientation of MSM twin variants in low-temperature martensite phase are subject to an ongoing research for almost two decades. However, the magnetic field distribution in the MSM elements and effects of its varying magnetic permeability on bias magnetic field are not well studied. In this paper we present an extension to the existing modeling approach for MSM elements applicable to actuator design. The effects arising from single-crystal anisotropy and demagnetization effects due to non-homogeneous multi-variant MSM microstructure are studied and discussed. The proposed approach is validated by comparing computational results with previously reported measurement data

Simulation-based Design Methodology for Magnetic Shape Memory Actuators

MSM alloys, especially Ni-Mn-Ga alloys have been studied extensively for almost two decades. Their remarkable properties make them very promising for use in various electromagnetic (EM) devices, notably in actuators and sensors. However, at present there are no well-established design methodologies for MSM-based devises. This paper proposes a design methodology that uses commercially available EM modelling software and just a small amount of experimental data for its implementation. It allows reliable actuator modelling and performance evaluation without needing to calculate the magnetic field-induced stresses

Electromagnetic and thermal analyses of high performance magnetic shape memory actuators for valve applications

Magnetic shape memory (MSM) alloys are relatively new “smart” alloys which have enormous potential to be used in actuators, sensors and other electrical devices. Their large strain and considerable stress output can be controlled by magnetic fields or mechanical stresses. Maximum magnetic field-induced strain varies from 6 to 12% of the MSM element’s length depending on its microstructure. However, very low operational temperature limit is one of the main drawbacks of conventional MSM alloys. This makes their application in high performance actuators challenging due to considerable power losses. This paper discusses different MSM actuator designs optimized particularly for large force output for pneumatic electromagnetic (EM) valve applications. The thermal problem is addressed through analyzing the heat transfer conditions of each particular design and the effects of different cooling systems. An energy-efficient operating cycle for varying actuator load that takes advantage of the shape memory effect is also proposed. This allows minimization of energy losses resulting in acceptable increase in temperature ensuring stable continuous actuation

Development of non-conventional instrument transformers (NCIT) using smart materials

In this paper is presented a novel approach for current measurement using smart materials, magnetic shape memory (MSM) alloys. Their shape change can be controlled by the application of magnetic field or mechanical stress. This gives the possibility to measure currents by correlating the magnetic field produced by the current, shape change in an MSM- based sensor and the voltage output of a Linear Variable Differential Transducer (LVDT) actuated by this shape change. In the first part of the paper is presented a review of existing current measurement sensors by comparing their properties and highlighting their advantages and disadvantages

Study of magnetic field distribution in anisotropic single twin-boundary magnetic shape memory (MSM) element in actuators

Magnetic shape memory effect exhibited by certain alloys at room temperature is known for almost 20 years. The most studied MSM alloys are Ni-Mn-Ga alloys which exhibit up to 12% magnetic field-induced strain (change in shape) depending on microstructure. A multibillion cycle operation without malfunction along with their "smart" properties make them very promising for application in electromagnetic (EM) actuators and sensors. However, considerable twinning stress of MSM crystals resulting in magneto-mechanical hysteresis decreases the efficiency and output force of MSM actuators. Whereas twinning stress of conventional MSM crystals has been significantly decreased over the years, novel crystals with Type II twin boundaries (TBs) possess even lower twinning stress. Unfortunately, the microstructure of MSM crystals with very low twinning stress tends to be unstable leading to their rapid crack growth. Whilst this phenomenon has been studied experimentally, the magnetic field distribution in anisotropic single twin-boundary MSM elements has not been considered yet. This paper analyses the magnetic field distribution in two-variant single twin-boundary MSM elements and discusses its effects on magnetic field-induced stress acting on the twin boundary

Modelling and design of high-speed, long-lifetime and large-force electromagnetic actuators based on magnetic shape memory alloys

The main topic of this research is modelling and design of high-speed, large-force and long life-time electromagnetic actuators based on Magnetic Shape Memory (MSM) alloys. These relatively new “smart” alloys that change shape in magnetic fields possess very promising properties such as large strain, considerable output stress and potentially very long fatigue life. However, there is still lack of a consistent design methodology for MSM-based devices which can be implemented using techniques common for engineering design. In order to bridge this gap, a modelling approach for MSM element in actuators is developed in which the complete magnetic circuit of MSM actuator is included into a single finite element (FE) model. This approach also allows accurate representation of MSM permeability change during the shape change capturing its effects on total reluctance of the magnetic circuit. Moreover, this approach allows studying the magnetic field distribution in the MSM element in single, two and multi-variant states in magnetic fields of varying strength. The modelling results show striking non-homogeneity of the magnetic field distribution, providing new insights on the magneto-mechanical behaviour of the MSM element. The modelling approach is verified through comparing the calculated MSM permeability change with previously reported results obtained by measurement. Using this modelling approach, electromagnetic analysis is conducted for eleven MSM actuators. The actuators are designed and optimised for a particular 0.1mm strain (displacement) and 10N force output for implementation in food-sorting machines. The conducted analysis also ensures robustness of the designs and stable multi-billion cycle operation. The very long lifetime is achieved through careful analysis of the magnetic circuit and the behaviour of the MSM element during operation. Finally, thermal analysis is conducted for the designed actuators in order to ensure their thermal stability. In order to overcome challenges associated with a very low operating temperature limit of the MSM element in actuators, different available cooling conditions are studied. Moreover, an energy-efficient operation cycle is developed that takes advantage of the shape memory effect of the MSM element also taking into account the pressure change in the pneumatic valve of a sorting machine. The analysis shows multiple regimes which allow thermal stability in a 300Hz pulsed excitation cycle. Implementation of the developed operating cycle also leads to the considerable increase in overall efficiency

Network human capital formation in the conditions of digital transformation of economy

The article reveals the pattern of network human capital formation. Network human capital has been proved to be closely connected and conditioned by digital transformation. On this basis, the relationship between network human capital formation and digital human capital has been substantiated. The purpose of the article is to consider a number of basic theoretical, methodological, and empirical foundations in the field of analysis of network human capital formation. Based on the analysis of a number of key studies in the area, it has been concluded that in the modern network economy, network human capital is determined by one of the most important strategic assets of organizations. It has been proposed to use the methodology of the Network Readiness Index to quantify network human capital. The theoretical and practical value of the proposed approach lies in the application of a methodology that gives priority to the human factor of network readiness and reflects the impact of individuals’ choices regarding technologies and management methods on innovative networks creation in the process of innovative technologies development and implementation. The emerging concept of network human capital is aimed at overcoming the digital inequality and using the Internet to implement positive social changes. This concept considers digital education in the context of the formation of an active socio-political position of human influence on society development

Comprehensive management of innovative development based on an integrated model of intellectual capital

The article puts forward a position according to which the achievement of effective innovation management is ensured by the balanced development of human, social, reputational and digital capital, leading to the formation of innovative capital. The relevance of the study is due to the global challenge of our time, which consists in the fact that an effective strategy for managing innovation and developing innovative capital is the basis for the formation of competitive advantages of national economies and firms. The aim of the research is to develop an integrated model of intellectual capital, which forms an up-to-date idea of its structure and clarifies the relationship between its components. The developed integrated model of intellectual capital substantiates the need to implement the integrated management of social, reputational, digital and innovative capital for the purpose of innovative development in modern conditions. The article reveals the mutual influence of human, social, reputational and innovative capital, as well as the formation of network human capital on this basis. As the main methodological principles and methods for studying innovative capital and other types of intangible capital as endogenous factors in managing innovative development, it is proposed to use the concepts of intellectual, social and reputational capital, the concepts of digital transformation and the principles of creating a creative environment. The integration of the methods of scientific knowledge used in these theories makes it possible to develop the concept of innovative capital. The subject of the study is the organizational and economic relations that arise in the process of interaction of social, reputational and digital human capital as components of network human capital, leading to the development of innovative capital. The novelty of the research lies in the developed model of connections between intellectual, human, social, reputational, digital capital and innovation capital. The authors substantiate the position according to which the traditional structure of intellectual capital hides the direct impact of human capital on other components of intellectual capital. As a basic element of intellectual capital, human capital not only plays an important role in the development and creation of new ideas and knowledge; it also promotes the development of social capital and the exchange of knowledge and ideas. The main conclusions of the work include: organizations with more developed human capital, participating in social networks and led by innovative leaders, adapt faster to the challenges of the innovative environment; invest in the formation of new skills and competencies of employees, which generates opportunities for the creation and implementation of large-scale innovations, the accelerated promotion of which is facilitated by the use of new network and digital technologies for the innovative development of the economy. The developed integrated model of intellectual capital is aimed at forming an actual representation of its structure and clarifies the relationship between its components. The results obtained are of great importance for practical management in the context of managing the innovative development of an organization

Ensuring the effectiveness of the privatization of state-owned companies in the conditions of instability of the financial markets (under the example of OJSC oil company 'rosneft')

The current state of the world and Russian economy makes it necessary to search for the additional sources of funding by the Government of the Russian Federation in terms of undervaluation of the Russian companies. The privatization strategy is aimed at regulation of the state budget deficit by attracting the maximum possible amount of cash flows at the present stage of development of the Russian economy. However, due to the volatility of financial and commodity markets, and imposed sanctions against the Russian companies, it raises the problem of an adequate assessment of the privatized assets. A potential stabilization of markets and the prospects of lifting of restrictions actualize the temporal aspects of privatization. The paper includes the assessment of the value of cash flows generated by the company and the shareholders' equity. A comparison of the cash flows of the company, attributable to the shareholders' equity, and its capitalization has allowed identifying the undervaluation or overvaluation of the companies. Cost evaluation of the OJSC "Oil Company "Rosneft" shows its undervaluation. This company is overburdened with debts, which indicates the inefficiency of its privatization in the current conditions. The undervaluation of the company by the investors is supported by a comparative analysis of the values of its financial multiples and financial multiples of foreign oil and gas companies. In the long term perspective the value of the company's cost of capital may be reduced, and the values of cash flows may be increased. This will lead to an increase in the value of the company's assets

Analysis of consumer behavior impact on human capital development through the example of the Altai Republic

The article examines the influence of the individual demand system on the creation, storage and usage of human capital. Personal motivation is expanding due to the development of needs, while the investments in the consumer sphere of human leads to the development of skills. Dialectical interaction of these skills leads to the increase of the role of human capital in modern economy. We explored the processes of the consumer behavior of individuals on the example of the economy of the Altai Republic. © IDOSI Publications, 2013