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The purpose of this paper is to evaluate the cogging torque in a surface-mounted permanent magnet (SPM) machine with both uniformly and non-uniformly segmented stator cores and to find out the optimal solution of stator core segmenting.

The cogging torque with segmented stators is synthesized from a single slot model, and analytical prediction is given to analyze the cogging torque with both uniformly and non-uniformly segmented stators. Finite element method (FEM) is used to figure out the electromagnetic field and validate the analytical prediction. Moreover, models with various shapes and positions of connecting tongues between the stator core segments are explored to achieve the optimal design.

The cogging torque is found to be greatly related to the number of segments and the electrical angle between adjacent additional air gaps caused by the tolerance of stator segments. Different shapes of the connecting tongues are tested and proved to be of great importance to the flux density, both radial and tangential, and therefore affect the cogging torque. Finally, position of the connecting tongues is perceived to have little influence on the performance of machine.

By utilizing analytical prediction and FEM calculation, the optimal solution is discussed to minimize the cogging torque in the SPM machine from the perspective of the stator core segmentation.

This paper establishes formula of cogging torque with segmented stators and predicts the variation of cogging torque with analytical method. Besides, different combinations of segments are compared and measures to reduce the cogging torque produced by the segmentation are proposed.

The purpose of this study is to estimate the sensitivity of cogging torque in permanent magnet (PM) motor designs due to PM assembly tolerance and/or PM imperfections and to evaluate how such faults can be reliably detected in simulated and measured cogging torque signals.

PM motors exhibit inherent cogging torque, which creates torque ripple and prevents smooth rotation of the rotor, resulting in undesirable vibration and noise. While cogging torque minimization is necessary to improve PM motor performance, several FEM models have been developed to study and present data demonstrating the sensitivity of cogging torque to PM assemblies and/or PM imperfections. Some procedures that would predict and evaluate cogging torque components relative to measured PM positions on assembled PM motors were proposed.

On the basis of numerous performed simulations using different FEM models and experimental results on rotors from mass‐production, it was found and proved that PM assembly tolerance and/or PM imperfections cause the phenomenon of additional cogging torque harmonic components. Considering the presented theoretical aspects motor designers can predict which additional harmonic components will comprise the cogging torque, as a result of which the appropriate technique for minimizing native and additional harmonic components can be applied.

The presented research of cogging torque sensitivity in different PM motor designs to assembly tolerance and/or PM imperfections should in future also consider stator irregularities and different methods of lamination stacking such as notches, welding, and interlocking.

By utilizing the presented method and considering recommendations, advanced motor designers have a reliable tool for predicting the order and level of additional harmonic components in total cogging torque. Thus, adequate critical manufacturing tolerances can be defined in order to achieve minimal waste in produced PM motors.

The originality of the paper is explained by the theoretical aspects and analytical equations of additional harmonic components in cogging torque of PM motors. Also original are the expressions for amplitude calculation of additional harmonic components influenced by manufacturing tolerances.

The purpose of this paper is to estimate and evaluate how cogging torque in permanent magnet (PM) motor designs is sensitive to the number of applied interlocks in stator back‐iron, which is a standard method for stator lamination stacking.

The PM motors exhibit inherent cogging torque, which creates torque ripple and prevents smooth rotation of the rotor resulting in undesirable vibration and noise. While cogging torque minimization is necessary to improve PM motor performance, several FEM models have been developed to study and present data demonstrating sensitivity of the cogging torque to the applied interlocks. A procedure that would predict and evaluate cogging torque components relative to chosen number and positions of interlocks was proposed.

On the basis of theoretical considerations, which were verified by numerous performed simulations using different FEM models, it was found out and proved that interlocks in the stator back‐iron cause the phenomenon of additional cogging torque harmonic components (AHC). Taking into account presented theoretical aspects motor designers can predict, which AHC will comprise the cogging torque. Each motor design has its own optimal value of interlocks, therefore a precise study should be performed during the design process.

By utilizing presented method and considering recommendations, advanced designers of PM motors will have a reliable tool for predicting the order and the level of AHC in total cogging torque due to the stator lamination stacking methods.

The paper presents theoretical aspects and analytical equations of AHC of PM motors. So far, the authors dealing with the cogging torque of the PM motors did not take into account the influence of the stator lamination stacking method on the level of torque oscillations. The new contribution is also the study of the sensitivity of different motor designs to the number and position of interlocks, which enables the minimization of the AHC in order to fulfil stringent market demands for low‐cogging torque level.

This paper describes the cogging torque of the permanent magnet synchronous (PM) motors due to the magnetic anisotropy of motor core. The cogging torque due to the magnetic anisotropy is calculated by the finite element method using two kinds of modeling methods: one is the 2D magnetization property method, and the other is the conventional method. As a result, the PM motors with parallel laminated core show different cogging torque waveform from the PM motors with the rotational laminated core due to the influence of the magnetic anisotropy. The amplitudes of the cogging torque are different depending on the modeling methods in the region of high flux density.

This paper presents the design techniques applied to a novel fractional-slot 6/4 pole permanent magnet brushless direct current (PMBLDC) motor, for cogging torque reduction. The notable feature of this motor is the simplicity of the design and low production cost. The purpose of this paper is to reduce the peak cogging torque of the motor. The focus is put on the stator topology tuning, and a new design for the stator poles is proposed. By determining the optimum stator pole arc length and the best pole shoe thickness, the cogging torque is significantly reduced. This new optimised motor design has been analysed in detail. The validation of the results is documented with respective figures and charts.

At the beginning, the design data for the 6/4 pole PMBLDC motor with concentrated three phase windings and asymmetric stator pole arcs is presented. In the study, this motor is taken as a reference model (A₀, T₀). A full performance finite element analysis of the reference motor has been carried out, and the weak points in the motor design have been identified. By simple design techniques, tuning the stator pole geometry, a two-stage design optimisation for cogging torque minimisation has been performed and the solution array has been derived. The optimised model is selected and proposed (A_opt, T_opt). The comparative analysis of the reference and optimised motors show the advantages of the proposed novel design and prove the methodology.

The results of the work demonstrate how simple design techniques can minimise the peak of the cogging torque profile, while maintaining the specified electromagnetic torque value. The sensitivity of the cogging torque profile because of changes of the stator pole design inside the prescribed constraints is apparent. The stator poles of the reference motor have an arc length of 85° and pole shoe thickness of 6 mm. The newly shaped stator poles have an arc length of 78.5° and pole shoe thickness 4.8 mm. The peak-cogging torque has been reduced from 0.158 Nm to a respectable value of 0.066 Nm. However, to reduce electromagnetic torque ripple and pulsations, further investigations are required.

The paper presents an approach to cogging torque reduction for a 6/4 PMBLDC motor. A two-step original design procedure is introduced and an optimised stator pole geometry is defined. The minimised cogging torque has been demonstrated with improved usage of the active materials. This work could serve as a good basis for further optimisation of the motor design.

The purpose of this paper is to investigate the performance of coke oven gas (COG)-combined cooling, heating and power (CCHP) system and to mainly focus on studying the influence of the environmental conditions, operating conditions and gas conditions on the performance of the system and on quantifying the distribution of useful energy loss and the saving potential of the integrated system changing with different parameters.

The working process of COG-CCHP was simulated through the establishment of system flow and thermal analysis mathematical model. Using exergy analysis method, the COG-CCHP system’s energy consumption status and the performance changing rules were analyzed.

The results showed that the combustion chamber has the largest exergy loss among the thermal equipments. Reducing the environmental temperature and pressure can improve the entire system’s reasonable degree of energy. Higher temperature and pressure improved the system’s perfection degree of energy use. Relatively high level of hydrogen and low content of water in COG and an optimal range of CH₄ volume fraction between 35 per cent and 46 per cent are required to ensure high exergy efficiency of this integration system.

This paper proposed a CCHP system with the utilization of coke oven gas (COG) and quantified the distribution of useful energy loss and the saving potential of the integrated system under different environmental, operating and gas conditions. The weak links of energy consumption within the system were analyzed, and the characteristics of COG in this way of using were illustrated. This study can provide certain guiding basis for further research and development of the CCHP system performance.

The purpose of this paper is to investigate the impact of the stator core design for a surface permanent magnet motor (SPMM) on the cogging torque profile. The objective is to show how the cogging torque of this type of motor can be significantly reduced by implementing an original compound technique by skewing stator slots and inserting wedges in the slot openings.

At the beginning generic model of a SPMM is studied. By using FEA, for this idealised assembly, characteristics of cogging and electromagnetic torque are simulated and determined for one period of their change. Afterwards, actual stator design of the original SPMM is described. It is thoroughly investigated and the torque characteristics are compared with the generic ones. While the static torque is slightly decreased, the peak cogging torque is almost doubled and the curve exhibits an uneven profile. The first method for cogging torque reduction is skewing the stator stack. The second technique is to insert wedges of SMC in the slot openings. By using 2D and 2 1/2D numerical experiment cogging curves are calculated and compared. The best results are achieved by combining the two techniques. The comparative analyses of the motor models show the advantages of the proposed novel stator topology.

It is presented how the peak cogging torque can be substantially decreased due to changes in the stator topology. The constraint is to keep the same stator lamination. By skewing stator stack for one slot pitch 10° the peak cogging torque is threefold reduced. The SMC wedges in slot opening decrease the peak cogging almost four times. The novel stator topology, a combination of the former ones, leads to peak cogging of respectable 0.182 Nm, which is reduced for 7.45 times.

The paper presents an original compound technique for cogging torque reduction, by combining the stator stack skewing and inserting SMC wedges in the slot openings.

The present study examines the relationship between personality traits (PTs) and conflict management styles (CMSs) directly and indirectly through leadership effectiveness (LE) in Pakistan.

This quantitative study employs a survey questionnaire to collect cross-sectional data from academic leaders of higher education institutes (HEIs) in Pakistan. The authors utilized 325 useable cases to conclude the results.

The findings through the structural equation model (SEM) resulted in a positive and significant effect of agreeableness (AGS) on integrating (ITG), avoiding (AVG), obliging (OBG), compromising (COG) and dominating (DOG) styles. Extraversion (EXN) positively and significantly affects ITG, OBG, DOG and COG. Emotional stability (EMSY) is a positive and significant predictor of ITG, AVG, OBG and COG. The conscientiousness (CNS) trait significantly and positively predicts ITG, OBG, DOG, COG and AVG. Likewise, openness (OPS) positively and significantly affects ITG, OBG, DOG and COG styles. On the other hand, EXN and OPS negatively and insignificantly affect AVG. Finally, EMSY is the negative and insignificant predictor of DOG among academic leaders.

This study offers additional insights into understanding direct and indirect connections between PTs and CMSs through EL. It would support the development of effective policies and organizational setup to resolve and manage conflict and employees' behaviour. Finally, the findings would further enrich the worth of literature through another empirical confirmation.

This study offers the original contribution of PTs and CMSs among academic leaders in HEIs of Pakistan.

This paper aims to investigate if the world top manufacturing corporations' cost structures are moving from tangible to intangible activities and their impact on profitability.

The theoretical approach is interdisciplinary, combining global value chains, international manufacturing networks, cost management literatures. The empirical approach has a sample out of financial statements' data from 220 multinational corporations between 2006 and 2017, grouping them by technological intensity. It is created the “COGS-share” indicator – the ratio between the costs of goods sold and overall costs and expenses – as a proxy for the firms' expenses of tangible and intangible value chain activities. It is tested as an explanatory variable for the companies' profits through dynamic panel data econometric models.

The results show that the cost structure still is very concentrated in tangibles. Though costs of both tangible and intangible activities negatively impact profits, they affect value generation differently: the higher the share of intangible in comparison to tangible activities in overall cost and expenses, the greater the profits in most manufacturing groups, regardless of their technological intensity.

The empirical analysis simplifies the composition of value chains per activity because financial statements data are aggregates, preventing detailed analysis by markets, business units or products. Stocks' levels are assumed to be at the desired level during the time series. The dataset does not allow value curves to be drawn because direct wages' data and more precise information on cost (especially deferred assets and wages) are missing.

The presented approach, particularly the COGS-share indicator, contribute to assess value generation from activities for improving corporate strategies and public policies on operations and cost management of global value chains.

Supporting upgrading decisions that impact value production, allocation and distribution between workers, firms and countries.

Interdisciplinary theoretical and empirical assessment of the manufacturing companies' cost structures and profits based on financial statements data for the better understanding of value generation from tangible and intangible activities.

This study aims to explore peer performance as the motivation behind gross profit manipulation through two different channels, namely, cost of goods sold (COGS) misclassification and revenue misclassification.

Gross profit expectation model (Poonawala and Nagar, 2019) and operating revenue expectation model (Malikov et al., 2018) are used to measure COGS and revenue misclassification, respectively. The panel data regression models are used to analyze the data for this study.

The study results show that firms engage in gross profit manipulation to meet the industry’s average gross margin, implying that peer performance is an important benchmark that firms strive to achieve through misclassification strategies. Further results exhibit that firms prefer COGS misclassification over revenue misclassification for manipulating gross profit, implying that firms choose the shifting strategy based on the relative advantage of each shifting tool.

The findings suggest that firms that just meet or slightly beat industry-average profitability levels are highly likely to engage in classification shifting (CS). Thus, investors and analysts should be careful when evaluating such firms by comparing them with other firms in the same industry.

First, this study is among earlier attempts to investigate CS motivated by peer performance. Second, this study investigates both tools of gross profit manipulation by taking a uniform sample of firms over the same period and provides compelling evidence that firms prefer one shifting tool over another depending on the relative advantage of each shifting tool.