Search results

Team-based assignments must be constructed to contribute to the effective development of teamwork skills, an important learning objective for most schools of business. The purpose of this paper is to understand how students view the usefulness of team assignments in order to inform more effective pedagogical techniques related to team-based assignments and the development of student teamwork competencies.

Data were collected from Likert-scale online surveys administered to students upon completion of the first-year team-based introductory business course. Survey items were developed to assess the team-related activities and components in the course and students’ perceived usefulness of team-based assignments. Results from exploratory factor analyses are presented.

Data analyses indicated that survey items contributed to students’ perceived usefulness of team-based assignments. Across three studies, the authors developed a new measure to evaluate effectiveness of team-based assignments.

For those educators who utilize team-based assignments in their courses, this study provides a much needed measure to assess the effectiveness of assignments intended to develop students’ teamwork competencies. The findings also serve to provide evidence of assurance of learning, and evidence of how students are developing in the area of interpersonal skills and abilities to manage interactions that most schools of business and universities deem as essential learning outcomes as a result of Association to Advance Collegiate Schools of Business requirements.

Evidence from online surveys of 755 students in a pilot study and two additional studies conducted longitudinally over a two-year period support a new measure to assess the usefulness of specific team assignments.

This paper presents the field‐circuit analysis of a disc‐type torus DC motor with permanent magnets. Calculations of the magnetic field are carried out using the finite element method (FEM) in the 3D space. The integral quantities like the ripple‐cogging torque, back electromotive force, flux linkage, self and mutual inductances of the winding are analyzed. The electromagnetic torque is comparatively determined from the Maxwell stress tensor and co‐energy methods. Based on the 3D magnetic field calculations, the lumped‐parameter model of the tested motor is constructed, taking into account an electronic power converter as well. For comparison, various permanent magnet widths and teeth thicknesses of the stator core are considered. The torque pulsations are shown in simulations to be effectively reduced by an appropriate selection of a permanent magnet width on the pole pitch. Additionally, the efficiency of the tested motor can be significantly improved by a proper selection of the teeth thickness. The simulation results are verified with experimental data obtained from the slotless version of the motor prototype.

A brushless, permanent magnet, three‐phase disc‐type salient‐pole DC motor with co‐axial flux in the stator is considered. Electromechanical properties of a basic eight‐pole motor are compared with those for a 16‐pole one of the same volume, in order to contrast the two potential candidates for variable‐speed, low‐cost drives. As a basis of the comparative analysis, 3D FEM magnetic field modelling and circuit analysis considering an electronic commutator are employed. Increasing the number of poles results in unfavourable raising in the switching frequency. The eight‐pole motor construction has been shown in simulations to have higher efficiency and lower power losses than its 16‐pole counterpart.

Aims to present a new approach for formulating state‐space equations of an electromechanical actuator using magnetic flux linkages as state variables.

The model is based on employment of discrete databases and their interpolation. The algorithm of determination of databases defining the flux/current characteristics of an actuator is described. Graphical interpretation of variable transformation is presented. A simplified, two‐axis model of reluctance motor is used to illustrate the application of the proposed modelling technique. Comparison with the classical model of the motor is used to verify the validity of the method. Analysis is focused on determination of saturation phenomenon influence on formulation methodology and on correctness of obtained results.

A very good agreement is observed between reference dq model and the proposed model. The main problem of the presented method is the existence of undefined entries in databases. Sufficiently dense databases can be used to overcome the problem.

The model is limited to actuators in which eddy currents and hysteresis phenomenon can be neglected. Future research will be concentrated on evaluation of different interpolation strategies of databases used in the model for realistic saturation conditions.

The model can be used as a library block for testing various control strategies for actuators without standard simplifying assumptions (e.g. sinusoidal winding distribution). It can be implemented in any simulational software (e.g. SIMULINK) as its block diagram is simple and no numerical differentiation is necessary in derivation of the model data.

Presents an extension of state‐space model of an actuator based on database discretised description of variables to two or more state variables.

Presents an approach to determine sources of cogging torque harmonics in permanent magnet electrical machines on the basis of variations of air‐gap magnetic flux density with time and space. The magnetic flux density is determined from the two‐dimensional (2D) finite element model and decomposed into the double Fourier series through the 2D fast Fourier transform (FFT). The real trigonometric form of the Fourier series is used for the purpose to identify those space and time harmonics of magnetic flux density whose involvement in the cogging torque is the greatest relative contribution. Carries out calculations for a symmetric permanent magnet brushless machine for several rotor eccentricities and imbalances.

This paper aims to present an analytical method, which combines the complex permeance (CP) and the superposition concept, to predict the air-gap magnetic field distribution in surface-mounted permanent-magnet (SMPM) machines with eccentric air-gap.

The superposition concept is used twice; first, to predict the magnetic field distribution in slot-less machine with eccentric air-gap, the machine is divided into a number of sections. Then, for each section, an equivalent air-gap length is determined, and the magnetic field distribution is predicted as a concentric machine model. The air-gap field in the slot-less machine with eccentricity can be combined from these concentric models. Second, the superposition concept is used to find the CP under eccentricity fault. At this end, the original machine is divided into a number of sections which may be different from the one for slot-less magnetic field prediction, and for each section, the CP is obtained by equivalent air-gap length of that section. Finally, the air-gap magnetic field distribution is predicted by multiplying the slot-less magnetic field distribution and the obtained CP.

The radial and tangential components of the air-gap magnetic flux density are obtained using the proposed method analytically. The finite element analysis is used to validate the proposed method results, showing good agreements with the analytical results.

This paper addresses the eccentricity fault impact upon the air-gap magnetic field distribution of SMPM machines. This is done by a combined analysis of the complex permeance (CP) method and the superposition concept. This contrasts to previous studies which have instead focused on the subdomain method.

The purpose of this paper is to minimize the torque pulsation in Halbach array permanent magnet synchronous machines (PMSMs).

Because of its specific structure, the cogging torque influences the main part of the torque pulsation in a Halbach array PMSM. In this paper, first it is shown that the conventional magnet skewing method does not have a significant effect on the torque pulsation in this motor, and then an improved skewing method with fewer skewing steps is proposed. In this method permanent magnet segments are placed sinusoidally, with two‐step skewing along the rotor. Generalization with different combinations of slots and poles is considered for a Halbach array PMSM.

Using a detailed finite element method (FEM) it was found that with the proposed technique the cogging torque factor is reduced to as low as 8 percent, while the average value of the torque is maintained near the machine nominal average torque.

Halbach array PMSMs are very good candidates for high dynamic performance applications such as aerospace applications due to their high acceleration and deceleration features. This technique also resolves the mechanical vibration and acoustic noise issues, which are caused by torque pulsation and significantly affect machine performance.

The originality of this paper lies in the FEM results. Since Halbach array PMSMs have a special structure it was shown that the conventional skewing method does not work well for this machine. The new proposed technique has a significant effect on the torque pulsation.

The alta mentoring platform, launched within the aviation and aerospace industry in 2019, is the outcome of a joint knowledge exchange project between academics and industry. It was designed and launched to meet the mentoring needs of women in this male dominated industry, who otherwise had no, or very little, mentoring support. The aim of alta was to create an on-line mentoring platform that was based upon the mentoring support that women identified as being important and that would address their under-representation and the lack of support for career progression. The chapter draws upon a body of literature focussing upon mentoring, specifically its meanings (see Dashper, 2018), benefits (see Phillips et al., 2016) and barriers (see Eby et al., 2010); as well as gender specific mentoring (see Johns & McNamara, 2014). The authors adopt a feminist relational mentoring framework (Ragins, 2016), that views mentoring as a two-way process where mentors and mentees learn from each other. The project was under-pinned by six months of research across the industry (a survey, interviews and focus groups with professional women and employers) to ascertain the need for the mentoring platform. This chapter is based upon four focus groups held with women across the industry, in both technical and middle/senior managerial roles, to ascertain their experiences of mentoring and their perceived and experienced benefits and barriers to mentoring. The focus groups were also utilised to find out specifically what women wanted from the alta mentoring platform and their views on its women-only focus.

The purpose of this paper is to elucidate the implications of relational cultural theory (RCT) for mentoring individuals who have enacted moral courage.

Overviews of the construct of moral courage, the nature of work-related mentoring and RCT are provided. Subsequently, the relevance and implications of RCT for understanding moral courage-related suffering, and for supporting the growth, resilience and vitality of those who have enacted moral courage are discussed.

Within RCT, moral courage-related suffering is located in disconnection, invalidation and isolation for which sufferers also feel held at fault. Self-protective behaviors, including disavowal of self, can perpetuate this suffering.

Five insights from RCT for supporting the growth, resilience and vitality of individuals following acts of moral courage are elaborated, including affirming efforts to activate supportive relationships; demonstrating “radical respect”; facilitating voice; engaging through mutuality and fluid expertise; and, reframing resilience.

The dearth of attention to ways of supporting those who suffer following acts of moral courage reflects previously documented findings about the short-shrift given to issues of human health and sustainability in organizations and organizational research. Implications for policy, practice and education are described.

This paper extends the RCT perspective in mentoring, and addresses an important gap in the moral courage literature, namely, the identification of a theoretically grounded approach through which to support the growth, resilience and vitality of individuals who have enacted moral courage.

The purpose of this paper is to elaborate the methodology and software for the optimization of rotor structure of the line-start permanent magnet synchronous motor (LSPMSM). To prove usefulness of presented approach the case study problem has been solved.

The modified particle swarm optimization (PSO) algorithm has been employed for the optimization of LSPMSM. The optimization solver has been elaborated in Delphi environment. The software consists of two modules: an optimization solver and a numerical model of LSPMSM. The model of the considered machine has been developed in the ANSYS Maxwell environment. In the optimization procedure the objective function has been based on maximizing efficiency and power factor.

Obtained results show that modified PSO algorithm can be successfully applied for the optimization of the rotor structure of LSPMSM. This software can be used as a design tool to improve the performance of LSPMSM. The results of studied case problem illustrate that it is possible to optimize rotor of LSPMSM to achieve good self-starting properties with simultaneous minimization of usage of permanent magnet material.

Both, the simpler lumped parameters model and more advanced field model of the motor were tested. Presented comparison to the results of the finite element analysis (FEA) shows that for considered in the paper the case study problem the accuracy of circuit model is acceptable.

Presented approach and developed software can be used as an effective design tool to improve the performance of LSPMSM.

The paper offers appropriate approach for optimizing the permanent magnet synchronous motors having ability to start by direct connection to the grid.