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1 – 10 of 542Mitja Garmut and Martin Petrun
This paper presents a comparative study of different stator-segmentation topologies of a permanent magnet synchronous machine (PMSM) used in traction drives and their effect on…
Abstract
Purpose
This paper presents a comparative study of different stator-segmentation topologies of a permanent magnet synchronous machine (PMSM) used in traction drives and their effect on iron losses. Using stator segmentation allows one to achieve more significant copper fill factors, resulting in increased power densities and efficiencies. The segmentation of the stators creates additional air gaps and changes the soft magnetic material’s material properties due to the cut edge effect. The aim of this paper is to present an in-depth analysis of the influence of stator segmentation on iron losses. The main goal was to compare various segmentation methods under equal excitation conditions in terms of their influence on iron loss.
Design/methodology/approach
A transient finite element method analysis combined with an extended iron-loss model was used to evaluate discussed effects on the stator’s iron losses. The workflow to obtain a homogenized airgap length accounting for cut edge effects was established.
Findings
The paper concludes that the segmentation in most cases slightly decreases the iron losses in the stator because of the overall reduced magnetic flux density B due to the additional air gaps in the magnetic circuit. An increase of the individual components, as well as total power loss, was observed in the Pole Chain segmentation design. In general, segmentation did not change the total iron losses significantly. However, different segmentation methods resulted in the different distortion of the magnetic field and, consequently, in different iron loss compositions. The analysed segmentation methods exhibited different iron loss behaviour with respect to the operation points of the machine. The final finding is that analysed stator segmentations had a negligible influence on the total iron loss. Therefore, applying segmentation is an adequate measure to improve PMSMs as it enables, e.g. increase of the winding fill factor or simplifying the assembly processes, etc.
Originality/value
The influence of stator segmentation on iron losses was analysed. An in-depth evaluation was performed to determine how the discussed changes influence the individual iron loss components. A workflow was developed to achieve a computationally cheap homogenized model.
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Oussama-Ali Dabaj, Ronan Corin, Jean-Philippe Lecointe, Cristian Demian and Jonathan Blaszkowski
This paper aims to investigate the impact of combining grain-oriented electrical steel (GOES) grades on specific iron losses and the flux density distribution within a…
Abstract
Purpose
This paper aims to investigate the impact of combining grain-oriented electrical steel (GOES) grades on specific iron losses and the flux density distribution within a single-phase magnetic core.
Design/methodology/approach
This paper presents the results of finite-element method (FEM) simulations investigating the impact of mixing two different GOES grades on losses of a single-phase magnetic core. The authors used different models: a 3D model with a highly detailed geometry including both saturation and anisotropy, as well as a simplified 2D model to save computation time. The behavior of the flux distribution in the mixed magnetic core is analyzed. Finally, the results from the numerical simulations are compared with experimental results.
Findings
The specific iron losses of a mixed magnetic core exhibit a nonlinear decrease with respect to the GOES grade with the lowest losses. Analyzing the magnetic core behavior using 2D and 3D FEM shows that the rolling direction of the GOES grades plays a critical role on the nonlinearity variation of the specific losses.
Originality/value
The novelty of this research lies in achieving an optimum trade-off between the manufacturing cost and the core efficiency by combining conventional and high-performance GOES grade in a single-phase magnetic core.
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The simulation of eddy currents in laminated iron cores by the finite element method (FEM) is of great interest in the design of electrical devices. Modeling each laminate by…
Abstract
Purpose
The simulation of eddy currents in laminated iron cores by the finite element method (FEM) is of great interest in the design of electrical devices. Modeling each laminate by finite elements leads to extremely large nonlinear systems of equations impossible to solve with present computer resources reasonably. The purpose of this study is to show that the multiscale finite element method (MSFEM) overcomes this difficulty.
Design/methodology/approach
A new MSFEM approach for eddy currents of laminated nonlinear iron cores in three dimensions based on the magnetic vector potential is presented. How to construct the MSFEM approach in principal is shown. The MSFEM with the Biot–Savart field in the frequency domain, a higher-order approach, the time stepping method and with the harmonic balance method are introduced and studied.
Findings
Various simulations demonstrate the feasibility, efficiency and versatility of the new MSFEM.
Originality/value
The novel MSFEM solves true three-dimensional eddy current problems in laminated iron cores taking into account of the edge effect.
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Ye Duan, Zenglin Han and Hailin Mu
There are certain differences in the production products of enterprises. What are the impacts of product differentiation on the iron and steel industry? Based on the macro…
Abstract
Purpose
There are certain differences in the production products of enterprises. What are the impacts of product differentiation on the iron and steel industry? Based on the macro background of CO2 emission reduction, this paper aims to analyze the economic benefits and environmental changes of the iron and steel industry under the dual influence of CO2 emission reduction policy and product differentiation policy.
Design/methodology/approach
Taking the basic data of iron and steel industry in six regions of China as an example, this paper constructed an extended two-stage dynamic game model to analyze the impact of product differentiation and carbon tax policy on the production, economic indicators and CO2 emission levels for the overall industry and regional enterprises.
Findings
As the CO2 emission reduction target increased, the unit carbon tax and total tax increased, whereas the macro-environmental losses, social welfare, consumer surplus and outputs decrease. Emission reduction pressures and other economic indicators showed obvious regional differences. Differentiated products promoted various indicators of enterprises and industries; higher degrees of product differentiation resulted in greater promoting effects on economic indicators.
Originality/value
This paper constructed multiple emission reduction and production backgrounds, and discusses the impact of the comprehensive implementation of these policies, which has been practically absent in previous studies. The results of this study are consistent with the current industrial policy for stable production and environmental protection, and also provides a reference for the formulation of detailed policies in the future.
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Thomas Wopelka, Ulrike Cihak-Bayr, Claudia Lenauer, Ferenc Ditrói, Sándor Takács, Johannes Sequard-Base and Martin Jech
This paper aims to investigate the wear behaviour of different materials for cylinder liners and piston rings in a linear reciprocating tribometer with special focus on the wear…
Abstract
Purpose
This paper aims to investigate the wear behaviour of different materials for cylinder liners and piston rings in a linear reciprocating tribometer with special focus on the wear of the cylinder liner in the boundary lubrication regime.
Design/methodology/approach
Conventional nitrided steel, as well as diamond-like carbon and chromium nitride-coated piston rings, were tested against cast iron, AlSi and Fe-coated AlSi cylinder liners. The experiments were carried out with samples produced from original engine parts to have the original surface topography available. Radioactive tracer isotopes were used to measure cylinder liner wear continuously, enabling separation of running-in and steady-state wear.
Findings
A ranking of the material pairings with respect to wear behaviour of the cylinder liner was found. Post-test inspection of the cylinder samples by scanning electron microscopy (SEM) revealed differences in the wear mechanisms for the different material combinations. The results show that the running-in and steady-state wear of the liners can be reduced by choosing the appropriate material for the piston ring.
Originality/value
The use of original engine parts in a closely controlled tribometer environment under realistic loading conditions, in conjunction with continuous and highly sensitive wear measurement methods and a detailed SEM analysis of the wear mechanisms, forms an intermediate step between engine testing and laboratory environment testing.
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Himani Naesstroem, Frank Brueckner and Alexander F.H. Kaplan
This paper aims to gain an understanding of the behaviour of iron ore when melted by a laser beam in a continuous manner. This fundamental knowledge is essential to further…
Abstract
Purpose
This paper aims to gain an understanding of the behaviour of iron ore when melted by a laser beam in a continuous manner. This fundamental knowledge is essential to further develop additive manufacturing routes such as production of low cost parts and in-situ reduction of the ore during processing.
Design/methodology/approach
Blown powder directed energy deposition was used as the processing method. The process was observed through high-speed imaging, and computed tomography was used to analyse the specimens.
Findings
The experimental trials give preliminary results showing potential for the processability of iron ore for additive manufacturing. A large and stable melt pool is formed in spite of the inhomogeneous material used. Single and multilayer tracks could be deposited. Although smooth and even on the surface, the single layer tracks displayed porosity. In case of multilayered tracks, delamination from the substrate material and deformation can be seen. High-speed videos of the process reveal various process phenomena such as melting of ore powder during feeding, cloud formation, melt pool size, melt flow and spatter formation.
Originality/value
Very little literature is available that studies the possible use of ore in additive manufacturing. Although the process studied here is not industrially useable as is, it is a step towards processing cheap unprocessed material with a laser beam.
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Chia-Jui Hsu, Jenifer Barrirero, Rolf Merz, Andreas Stratmann, Hisham Aboulfadl, Georg Jacobs, Michael Kopnarski, Frank Mücklich and Carsten Gachot
To decrease wear and friction, zinc dialkyldithiophosphate (ZDDP) has been used in engine oil for several decades, but the mechanism of the tribofilm formation is still unclear…
Abstract
Purpose
To decrease wear and friction, zinc dialkyldithiophosphate (ZDDP) has been used in engine oil for several decades, but the mechanism of the tribofilm formation is still unclear. The purpose of this study is to characterize the chemical details of the tribofilm by using high-resolution approaching.
Design/methodology/approach
An ISO VG 100 mineral oil mixed with ZDDP was used in sliding tests on cylindrical roller bearings. Tribofilm formation was observed after 2 h of the sliding test. X-ray photoelectron spectroscopy (XPS) and atom probe tomography (APT) were used for chemical analysis of the tribofilm.
Findings
The results show that the ZDDP tribofilm consists of the common ZDDP elements along with iron oxides. A considerable amount of zinc and a small amount of sulfur were observed. In particular, an oxide interlayer with sulfur enrichment was revealed by APT between the tribofilm and the steel substrate. The depth profile of the chemical composition was obtained, and a tribofilm of approximately 40 nm thickness was identified by XPS.
Originality/value
A sulfur enrichment at the interface is observed by APT, which is beneath an oxygen enrichment. The clear evidence of the S interlayer confirms the hard and soft acids and bases principle.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0035/
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Khavhatondwi Rinah Netshiheni, Mpho Edward Mashau and Afam Israel Obiefuna Jideani
White maize-based porridge is a staple food for about 80 per cent consumers in South Africa and in other sub-Saharan African countries contributing significantly to the diet of…
Abstract
Purpose
White maize-based porridge is a staple food for about 80 per cent consumers in South Africa and in other sub-Saharan African countries contributing significantly to the diet of rural population in developing countries. White maize is deficient in some amino acids and over-dependency on its porridge may lead to high prevalence of malnutrition-related health conditions. Moringa oleifera (MO) and termite (Macrotermes falciger) are known to contain substantial amount of protein. The purpose of this study was to determine the effect of powders from MO leaves and termite on the nutritional and sensory properties of instant maize porridge.
Design/methodology/approach
Inclusion of MO and termite powder in instant maize porridge, using different treatments were considered using a completely randomised design. Factor levels were control (maize flour) cooked, blanched and uncooked MO samples. Data were analysed using SPSS version 23.
Findings
Protein content of fortified instant maize porridge (FMP) significantly increased from 10.0 to 21.2 per cent compared to unfortified porridge, and this could be attributed to the substitution effect, as fresh uncooked MO leaves are reported to be high in protein. Mineral content of FMP was higher in zinc, iron, calcium and magnesium. Calcium values of FMP were higher (276.8 mg/100 g) compared to unfortified porridge (7.1 mg/100 g). Upon the addition of MO leaves and termite powder, the zinc content increased from 3.4 mg/100to 7.6 mg/100 g. Higher iron values (27.9-36.9 mg/100 g) were observed among fortified samples. The sensory result showed that control sample had higher acceptance than the fortified samples (p = 0.02). Sensory analysis showed that among fortified porridges, blanched sample was rated high for colour and texture, cooked sample was higher in taste and uncooked sample was higher for aroma. Control sample had higher acceptance than fortified porridges for taste. The results of this study showed that the addition of MO leaves and termite powder to instant maize porridge has led to a substantial increase in the nutritional value of FMP.
Originality/value
This study was carried out to develop instant maize porridge fortified with MO leaves and termite powder suitable for infants, pregnant mothers and other maize consumers. The author aimed at improving the nutritional content of instant maize porridge by combining it with MO leaves and termite powders. The results showed that the addition of MO leaves and termite powders to instant maize porridge has led to a substantial increase in the nutritional value of FMP. Therefore, powder from MO leaves and termites could be used in complementary foods to increase protein and mineral contents.
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Giorgio Locatelli, Alessandro Paravano, Marco Terenzi and Paolo Trucco
During the planning and delivery, iron triangle criteria, are essential for internal stakeholders (e.g. owner, sponsors and delivery company), mostly ignoring external…
Abstract
Purpose
During the planning and delivery, iron triangle criteria, are essential for internal stakeholders (e.g. owner, sponsors and delivery company), mostly ignoring external stakeholders such as local communities (often perceived as inconvenient) or end users. In the medium-long term, infrastructure cost and benefit are far more important for external stakeholders and the environment.
Design/methodology/approach
The iron triangle criteria, i.e. delivering on time, budget and quality/scope, is the traditional perspective to assess the success of infrastructure projects. Delivering on cost and time is significant, but particularly for infrastructure, there are more relevant success criteria. The authors argue which criteria are important, and explain why.
Findings
The authors challenge the traditional view of judging projects based on respecting time, budget and quality/scope. The authors explain that discussing the social value and contribution to achieving the UN Sustainable Development Goals (SDGs) is extremely relevant. Crucially these metrics keep changing, even after the project is terminated.
Originality/value
The authors provide a new seven-step action plan for decision-makers to improve infrastructure provision by reflecting on SDGs and engaging with external stakeholders, particularly minorities and the weaker members of their communities. Such an action plan is focused on the cost and value for different stakeholders on different timeframes and progress toward social value and achieving SDGs.
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Philipp Geiberger, Zhendong Liu, Mats Berg and Christoph Domay
For billing purposes, heavy-haul locomotives in Sweden are equipped with on-board energy meters, which can record several parameters, e.g., used energy, regenerated energy, speed…
Abstract
Purpose
For billing purposes, heavy-haul locomotives in Sweden are equipped with on-board energy meters, which can record several parameters, e.g., used energy, regenerated energy, speed and position. Since there is a strong demand for improving energy efficiency in Sweden, data from the energy meters can be used to obtain a better understanding of the detailed energy usage of heavy-haul trains and identify potential for future improvements.
Design/methodology/approach
To monitor energy efficiency, the present study, therefore, develops key performance indicators (KPIs), which can be calculated with energy meter data to reflect the energy efficiency of heavy-haul trains in operation. Energy meter data of IORE class locomotives, hauling highly uniform 30-tonne axle load trains with 68 wagons, together with additional data sources, are analysed to identify significant parameters for describing driver influence on energy usage.
Findings
Results show that driver behaviour varies significantly and has the single largest influence on energy usage. Furthermore, parametric studies are performed with help of simulation to identify the influence of different operational and rolling stock conditions, e.g., axle loads and number of wagons, on energy usage.
Originality/value
Based on the parametric studies, some operational parameters which have significant impact on energy efficiency are found and then the KPIs are derived. In the end, some possible measures for improving energy performance in heavy-haul operations are given.
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