M.R. Pagnola, F.D. Saccone, A. Ozols and H. Sirkin
The purpose of this paper is to introduce a simplified method, based on an improvement to the actual second‐order approximation to magnetic hysteresis curves, to calculate an…
Abstract
Purpose
The purpose of this paper is to introduce a simplified method, based on an improvement to the actual second‐order approximation to magnetic hysteresis curves, to calculate an estimation of quasi‐static hysteresis loops of ferromagnetic materials.
Design/methodology/approach
The addition of a new dB(B) function is proposed to second‐order rational approximation for the upward and downward magnetic quasi‐static hysteresis loop. The new semi‐empirical approach is tested with typical cycles of commercial Ni‐ferrites (ferroxcube) and Ni standards using a vibrating sample magnetometer (VSM).
Findings
The model is simple and a fast tool to reproduce with reasonable accuracy the hysteresis loops based on appropriate parameters of materials under analysis. The proposed extension to the Rivas model has reduced the maximum difference between experimental and modeled values from 19 to 0.08 per cent in the approximation to different hysteresis cycles of the magnetic materials studied here.
Originality/value
This paper presents an improvement to second‐order rational functions approach for fitting of hysteresis loops with simple added functions.
Details
Keywords
Jungang Wang and Zhiliang Zeng
The purpose of this study is to propose a new magnetic gearing device and the proposed transmission model can be applied in the field of wind power and wave energy generation…
Abstract
Purpose
The purpose of this study is to propose a new magnetic gearing device and the proposed transmission model can be applied in the field of wind power and wave energy generation gearboxes.
Design/methodology/approach
A novel radial differential field-modulated two-stage magnetic gear is introduced, using a unique radial differential linkage to integrate two single-stage magnetic gears. This design incorporates a magnetic isolation ring to enhance transmission efficiency by minimizing magnetic interference and preventing power circulation. The two-stage modulating ring rotor operates synchronously via a connecting bridge, ensuring system stability and efficiency. This configuration not only boosts the gear ratio but also maintains a compact structure, improving power density and efficiency. Leveraging the magnetic field modulation and differential transmission, a finite element model of this gear is developed and its electromagnetic performance is analyzed.
Findings
The torque density of the new radial differential field-modulated two-stage magnetic gear has increased by 44.97% compared to the traditional tandem two-stage magnetic gear. It achieves a high transmission ratio of 64 and maintains comparable power density, indicating strong torque transfer capabilities suitable for low-speed, high-torque applications. During steady-state operation, the torque pulsation difference between the two stages is minimal, ensuring stable working torque.
Social implications
This research not only propels the forefront of magnetic gear technology through heightened efficiency and streamlined design but also bears profound societal significance in fostering sustainable energy paradigms. By facilitating superior energy conversion efficiencies in wind turbines and wave energy converters, it plays a pivotal role in mitigating carbon emissions and accelerating the global pivot towards cleaner, renewable energy landscapes.
Originality/value
A magnetic gear transmission device is proposed, which can achieve high power density and large transmission ratio at the same time, and this study provides a useful reference for the design optimization of new high-performance multistage magnetic gears.
Details
Keywords
Guido Saccone, Ali Can Ispir, Bayindir Huseyin Saracoglu, Luigi Cutrone and Marco Marini
The purpose of this study is to provide the description of a computational methodology to model the combined propulsive systems of hydrogen propelled air-breathing scramjet…
Abstract
Purpose
The purpose of this study is to provide the description of a computational methodology to model the combined propulsive systems of hydrogen propelled air-breathing scramjet vehicles and to evaluate the pollutant and climate-changing emissions.
Design/methodology/approach
Emissions indexes of nitrogen oxide (EINO) and water vapour released by the air turbo rocket (ATR) and dual mode ramjet (DMR) engines of the STRATOFLY air-breathing, hypersonic scramjet vehicle, propelled by hydrogen/air were evaluated. ATR engine operation was assessed for several cruise conditions in both subsonic and supersonic flight regimes in Ecosimpro software, which is an object-oriented thermodynamic design and simulation platform. ATR combustor inlet flow conditions play a key role in the computation of species mass fractions, and these conditions are highly dependent on turbomachinery performance and engine flight regime. A propulsive operational database was created by varying mass flow rates of fuel and flight conditions such as cruise speed and altitude to investigate possible engine operations. The all-inlet conditions in this map are provided to the Cantera-Python chemical/combustion chemistry solver implementing a specially designed and formulated 0D kinetic-thermodynamic methodology successfully used to model and simulate the electric spark ignition required to activate the combustion process of the reacting mixture in the ATR combustion chambers, whereas the coupled aero-thermodynamic/aero-propulsive 0D/1D code i.e. Scramjet PREliminary Aerothermodynamic Design (SPREAD), designed and developed by the Italian Aerospace Research Centre (CIRA) was used for DMR calculations. Results show low emissions of NO according to the optimized design of the ATR; on the other hand, a tuning of operational conditions is needed for DMR, with its complete re-design to be more conclusive. Analogously, the released amount of water vapour is in good agreement with the required combustion efficiency and the expected propulsive performance.
Findings
Results show low emissions of NO according to the optimized design of the ATRs; on the other hand, a tuning of operational conditions is needed for DMR, with its complete re-design to be more conclusive. Analogously, the released amount of water vapour is in good agreement with the required combustion efficiency and the expected propulsive performance.
Originality/value
Applications of innovative 0D/1D chemical kinetic methodology and in-house codes.
Details
Keywords
A simple interaction‐potential model has been established to calculate the higher order elastic constants of intermetallic YbAl2 in the temperature range from 10‐300K. Temperature…
Abstract
A simple interaction‐potential model has been established to calculate the higher order elastic constants of intermetallic YbAl2 in the temperature range from 10‐300K. Temperature dependent second and third order elastic constants are used for the determination of the ultrasonic attenuation, velocity, Grüneisen numbers, Acoustic‐coupling constants, and thermal relaxation time at the different temperatures. Temperature dependency of the ultrasonic properties of YbAl2 is similar at low temperatures to that of pure metals and the low carrier heavy fermion systems ‐ LaSb, YbAs and YbP having simple NaCl‐type structures. Thermal energy density makes significant contribution to the total attenuation in the compound at the higher temperatures from 100‐300K. Effect of the magnetic field on the ultrasonic attenuation is also evaluated using the magneto resistance data. At 100K, the effect of the magnetic field becomes insignificant. The attenuation decreases with the field at 3K to 50K.
Details
Keywords
A case study is given of International Distillers & Vintners(UK) Limited (IDV (UK)) and an assessment made of the viability oftranslating theory into practice in the real world �…
Abstract
A case study is given of International Distillers & Vintners (UK) Limited (IDV (UK)) and an assessment made of the viability of translating theory into practice in the real world – the importance of having a strategy, of strategic planning, and having a success factor as a key component of an organisation′s competitive advantage. Following the appointment of a new managing director at IDV (UK) in 1982, three goals were established: (1) to more than double profits within five years; (2) to increase return on capital employed by almost 50 per cent within five years; and (3) to be the outstanding wine and spirit company in the UK. A sound strategy was required to achieve these goals. The historic background of the organisation is given and the strategic position of IDV (UK) in relation to its competitors and market share is described. A review of the state of the market is given and possible areas for expansion discussed. The quality and pedigree of certain brands and the quality and strength of leadership are proposed as the success factors upon which IDV (UK) could build. Details are given of how the organisation built upon these factors to achieve strategic success; the lessons learned; and the level of achievement and success in the marketplace.
Details
Keywords
Pradeep Kumar Choudhury and Angrej Singh Gill
Purpose: Although the transnational mobility of youth is prevalent across the globe, the policies and strategies used by developing countries to promote youths’ transnational…
Abstract
Purpose: Although the transnational mobility of youth is prevalent across the globe, the policies and strategies used by developing countries to promote youths’ transnational mobility remains unclear. This chapter aims to discuss a few emerging trends and concerns related to youth transnational mobility and human capital accumulation. It focuses on the specific case of youth transnational migration from India. As such, this chapter considers the factors that have led to the construction of aspirations for transnational migration among Indian youth.
Study approach: In this chapter, we examine youth transnational mobility by synthesising the major literature available in the area of globalisation and transnational migration in the developing countries context. The study also incorporates the policy debates and secondary data evidence in these domains to substantiate the arguments.
Findings: Mainly focussing on the internal state of affairs of India, this work highlights three critical issues (a) new norms and practices of human capital accumulation within India’s knowledge economy; (b) understanding state and formal-informal ‘commoditised’ market dynamics in the changing aspirations for global human capital formation, specifically through transnational migration; and (c) examining the upshots of youth transnational mobility in terms of the production of relatively new forms of caste and class inequalities within Indian society.
Originality: This conceptual piece of work is an initial foray to unpack the complexities of Indian youths’ migration for specialised forms of human capital accumulation in a global landscape. The study motivates future policy-oriented interdisciplinary research on education and transnational mobility, specifically in empirical research projects.
Details
Keywords
The second part of a case study of the marketing strategy of International Distillers & Vintners (UK) Limited, the first part of which was published in Vol. 3 No. 1 of this…
Abstract
The second part of a case study of the marketing strategy of International Distillers & Vintners (UK) Limited, the first part of which was published in Vol. 3 No. 1 of this journal. A wide‐ranging and detailed description is given of the company's success factors, strategic direction, brand strategies, new brand developments, acquisitions and disposals. An assessment of the lessons and achievements of the company's strategy and an action checklist for strategic planning is provided. The conclusion is that one of the smallest top management teams in the business has quadrupled the company's profits within seven years by creating a strategic blueprint for the rest of the industry to follow, with its emphasis on concentrating management time and attention on premium brands.
Details
Keywords
Sustaining business performance in an ever changing economic and technical environment is a challenge to be addressed with relevant management implements. This goal can be…
Abstract
Sustaining business performance in an ever changing economic and technical environment is a challenge to be addressed with relevant management implements. This goal can be achieved by using business modelling by processes allowing for costing deliverables, controlling operations and designing information sytems aligned with business procedures and organisation. It has to be stressed that the same process model can fulfill the three purposes above mentioned so that coherent views are secured for the various business stakeholders. In addition, adequate descriptions of business processes can “scavenge” the features of business assets such as organisation, personnel qualification, information systems to be taken into account in strategic decisions.
Details
Keywords
This chapter examines how groups' tactical selection shapes social movement mobilization and survival. I focus on 35 Indivisible groups founded in 10 American cities immediately…
Abstract
This chapter examines how groups' tactical selection shapes social movement mobilization and survival. I focus on 35 Indivisible groups founded in 10 American cities immediately after the 2017 Women's March. I analyze the descriptions of over 8,000 events on group Facebook pages from 2017–2019 and conduct 25 interviews with group members. These data allow me to assess how the type, diversity, and flexibility of tactics shape group mobilization and survival. I find that groups that use more protest and electoral tactics and those that use a diversity of tactics host more events and are more likely to survive over time. Being consistent in tactics was successful when groups used political tactics, particularly protest and electoral activities. Groups that engaged in a variety of tactics could also be successful, particularly in smaller and more conservative settings. This research illuminates the complex and situational ways that tactical choices matter for social movement longevity.