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1 – 10 of 50Johann Valentowitsch, Michael Kindig and Wolfgang Burr
The effects of board composition on performance have long been discussed in management research using fractionalization measures. In this study, we propose an alternative…
Abstract
Purpose
The effects of board composition on performance have long been discussed in management research using fractionalization measures. In this study, we propose an alternative measurement approach based on board polarization.
Design/methodology/approach
Using an exploratory analysis and applying the polarization measure to German Deutscher Aktienindex (DAX)-, Midcap-DAX (MDAX)- and Small Cap-Index (SDAX)-listed companies, this paper applies the polarization index to examine the relationship between board diversity and performance.
Findings
The results show that the polarization concept is well suited to measure principal-agent problems between the members of the management and supervisory boards. We reveal that board polarization is negatively associated with firm performance, as measured by return on investment (ROI).
Originality/value
This exploratory study shows that the measurement of board polarization can be linked to performance differences between companies, which offers promising starting points for further research.
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Hafte Gebreselassie Gebrihet and Martin Limbikani Mwale
The purpose of this study is to examine the effect of polarisation on trust in government.
Abstract
Purpose
The purpose of this study is to examine the effect of polarisation on trust in government.
Design/methodology/approach
The authors use the ordered probit technique to model trust as a function of polarisation and various control variables. The authors apply the instrumental variables approach to address potential endogeneity in polarisation, using ethnic diversity as an instrument.
Findings
The results reveal that an increase in polarisation reduces trust in central government. However, trust in local government is non-responsive to this polarisation. The estimations controlled for government performance, and the authors found a positive association between government performance and trust in government, which, however, does not alter the relationship between polarisation and trust in government.
Practical implications
In ethnically polarised nations, policymakers should consider decentralisation measures. This can help sustain trust and development support, particularly in regions where citizens prioritise ethnicity over nationality.
Social implications
The social implications of this research underscore the importance of promoting trust in government to foster social cohesion and stability, particularly in ethnically diverse societies.
Originality/value
The authors find that increased ethnic polarisation reduces trust in the central government, particularly among those prioritising their ethnicity over nationality. This adds a non-performance dimension to government trust literature, suggesting that policies focusing solely on performance may yield limited results. The research extends beyond central government trust to include local governments. Unlike central government, local government trust remains tied to performance attributes unaffected by polarisation. Hence, investing resources through local governments is a viable strategy for enhancing citizen support while mitigating polarisation’s adverse effects.
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Dongyang Li, Guanghu Yao, Yuyuan Guan, Yaolei Han, Linya Zhao, Lining Xu and Lijie Qiao
In this paper, the authors aim to study the effect of hydrogen on the pitting corrosion behavior of Incoloy 825, a commonly used material for heat exchanger tubes in hydrogenated…
Abstract
Purpose
In this paper, the authors aim to study the effect of hydrogen on the pitting corrosion behavior of Incoloy 825, a commonly used material for heat exchanger tubes in hydrogenated heat exchangers.
Design/methodology/approach
The pitting initiation and propagation behaviors were investigated by electrochemical and chemical immersion experiments and observed and analyzed by scanning electron microscope and energy dispersive spectrometer methods.
Findings
The results show that hydrogen significantly affects the electrochemical behavior of Incoloy 825; the self-corrosion potential decreased from −197 mV before hydrogen charging to −263 mV, −270 mV and −657 mV after hydrogen charging, and the corrosion current density increased from 0.049 µA/cm2 before hydrogen charging to 2.490 µA/cm2, 2.560 µA/cm2 and 2.780 µA/cm2 after hydrogen charging. The pitting susceptibility of the material increases.
Originality/value
Hydrogen is enriched on the precipitate, and the pitting corrosion also initiates at that location. The synergistic effect of hydrogen and precipitate destroys the passive film on the metal surface and promotes pitting initiation.
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Sally Elkatatny, Lamiaa Zaky, Walaa Abdelaziem and Aliaa Abdelfatah
This study aims to investigate the corrosion behavior of cold-rolled Fe35Ni20Cr12Mn(28-x)Alx high-entropy alloys (HEAs) using the potentiodynamic polarization technique in 1 M H2SO…
Abstract
Purpose
This study aims to investigate the corrosion behavior of cold-rolled Fe35Ni20Cr12Mn(28-x)Alx high-entropy alloys (HEAs) using the potentiodynamic polarization technique in 1 M H2SO4 acid. Additionally, the influence of molybdenum (Mo) additions as inhibitors and the effect of variations in cold rolling reduction ratios and Al content on corrosion behavior are examined.
Design/methodology/approach
Two cold rolling reduction ratios, namely, 50% (R50) and 90% (R90), were examined for the cold-rolled Fe35Ni20Cr12Mn28Al5 (Al5) and Fe35Ni20Cr12Mn23Al10 (Al10) HEAs. Mo inhibitor additions were introduced at varying concentrations of 0.3, 0.6 and 0.9 Wt.%. The potentiodynamic polarization technique was used to evaluate the corrosion rates (CRs) under different experimental conditions.
Findings
The results indicate that the addition of 0.3 Wt.% Mo in 1 M H2SO4 yielded the lowest CR for both R50 and R90, irrespective of the Al content in the HEAs. However, the highest CR was observed at 0.6 Wt.% Mo addition. Furthermore, increasing the concentration of Al resulted in a corresponding rise in the CR. Comparatively, the CR decreased significantly when the cold rolling reduction ratio increased from R50 to R90.
Originality/value
This research provides valuable insights into the intricate relationship between Mo inhibitors, cold rolling reduction ratio, Al content and the resulting corrosion behavior of Fe35Ni20Cr12Mn(28-x)Alx HEAs. The comprehensive analysis of corroded HEAs, including surface morphology, compositions and elemental distribution mapping, contributes to the understanding of the corrosion mechanisms and offers potential strategies for enhancing the corrosion behavior of HEAs.
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The purpose of this paper is to extract electrochemical reaction kinetics parameters, such as Tafel slope, exchange current density and equilibrium potential, which cannot be…
Abstract
Purpose
The purpose of this paper is to extract electrochemical reaction kinetics parameters, such as Tafel slope, exchange current density and equilibrium potential, which cannot be directly measured, this study aims to propose an improved particle swarm optimization (PSO) algorithm.
Design/methodology/approach
In traditional PSO algorithms, each particle’s historical optimal solution is compared with the global optimal solution in each iteration step, and the optimal solution is replaced with a certain probability to achieve the goal of jumping out of the local optimum. However, this will to some extent undermine the (true) optimal solution. In view of this, this study has improved the traditional algorithm: at each iteration of each particle, the historical optimal solution is not compared with the global optimal solution. Instead, after all particles have iterated, the optimal solution is selected and compared with the global optimal solution and then the optimal solution is replaced with a certain probability. This to some extent protects the global optimal solution.
Findings
The polarization curve plotted by this equation is in good agreement with the experimental values, which demonstrates the reliability of this algorithm and provides a new method for measuring electrochemical parameters.
Originality/value
This study has improved the traditional method, which has high accuracy and can provide great support for corrosion research.
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Yinghong Li, Wei Tan, Wenjie Pei and Guorui Zhu
The purpose of this paper is to investigate the effect of NaCl solution with different concentrations on impact-sliding fretting corrosion behavior of Inconel 690TT steam…
Abstract
Purpose
The purpose of this paper is to investigate the effect of NaCl solution with different concentrations on impact-sliding fretting corrosion behavior of Inconel 690TT steam generator heat transfer tubes.
Design/methodology/approach
The optical 3D profiler was used to measure the wear profile and calculated the wear volume. Corrosion behavior was studied using open circuit potential monitoring and potentiodynamic polarization testing. The morphologies and elemental distributions of wear scars were analyzed using scanning electron microscopy and energy-dispersive spectroscopy. The synergism of wear and corrosion was analyzed according to the ASTM G119 standard.
Findings
The corrosion tendency reflected by OCP and the corrosion current calculated by Tafel both increased with the increase of NaCl concentration. The total volume loss of the material increased with concentration, and it was known from the synergism that the volume loss caused by corrosion-enhanced wear accounted for the largest proportion, while the wear-enhanced corrosion also made a greater contribution to volume loss than tangential fretting corrosion. Through the analysis of the material morphologies and synergism of wear and corrosion, the damage mechanism was elucidated.
Originality/value
The research findings can provide reference for impact-sliding fretting corrosion behavior of Inconel 690TT heat transfer tubes in NaCl solution with different concentrations.
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This paper aims to achieve phosphating via optimal features of Mg metal as a suitable base coating, which is considered for other properties such as barrier properties against the…
Abstract
Purpose
This paper aims to achieve phosphating via optimal features of Mg metal as a suitable base coating, which is considered for other properties such as barrier properties against the passage of several factors.
Design/methodology/approach
In this research, in the phosphate bath, immersion time, temperature and the content of sodium nitrite as an accelerator were changed.
Findings
As a result, increasing the immersion time of AZ31 Mg alloy samples in the phosphating bath as well as increasing the ratio of sodium dodecyl sulfate (SDS) concentration to sodium nitrite concentration in the phosphating bath formulation increase the mass of phosphating formed per unit area of the Mg alloy. The results of the scanning electron microscope test showed phosphating is not completely formed in short immersion times, which is a thin and uneven layer.
Research limitations/implications
Mg and its alloys are sensitive to galvanic corrosion, which would lead to generating several holes in the metal. As such, it causes a decrease in mechanical stability as well as an unfavorable appearance.
Practical implications
Mg is used in several industries such as automobile and computer parts, mobile phones, astronaut compounds, sports goods and home appliances.
Social implications
Nevertheless, Mg has high chemical reactivity, so an oxide-hydroxide layer is formed on its surface, which has a harmful effect on the adhesion and uniformity of the coating applied on Mg.
Originality/value
By increasing the ratio of SDS concentration to sodium nitrite concentration in the phosphating bath, the corrosion resistance of the phosphating increases.
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This study aims to investigate the individual electrochemical transients arising from local anodic events on stainless steel, to uncover the potential mechanisms producing…
Abstract
Purpose
This study aims to investigate the individual electrochemical transients arising from local anodic events on stainless steel, to uncover the potential mechanisms producing different types of transients and to derive appropriate parameters indicative of the corrosion severity of such transient events.
Design/methodology/approach
An equivalent circuit model was used for the transient analysis, which was performed using a local current allocation rule based on the relative instant cathodic resistance of the coupled electrodes, as well as the kinetic parameters derived from the electrochemical polarization measurement.
Findings
The shape and size of the electrochemical current transients arising from SS 316 L were influenced by the film stability, local anodic dissolution kinetics and the symmetry of the cathodic kinetics between the coupled electrodes, where the ultralong transient might correspond to the propagation of film damage with a slow anodic dissolution rate. The dynamic cathodic resistance during the final stage of transient current growth can serve as a characteristic parameter that reflects the loss of passive film protection.
Originality/value
Estimation of the local anodic current trace opens a new way for individual electrochemical transient analysis associated with the charges involved, local current densities and changes in film resistance throughout localized corrosion processes.
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Managers must make numerous strategic decisions in order to initiate and implement a business model innovation (BMI). This paper examines how managers perceive the management team…
Abstract
Purpose
Managers must make numerous strategic decisions in order to initiate and implement a business model innovation (BMI). This paper examines how managers perceive the management team interacts when making BMI decisions. The paper also investigates how group biases and board members’ risk willingness affect this process.
Design/methodology/approach
Empirical data were collected through 26 in-depth interviews with German managing directors from 13 companies in four industries (mobility, manufacturing, healthcare and energy) to explore three research questions: (1) What group effects are prevalent in BMI group decision-making? (2) What are the key characteristics of BMI group decisions? And (3) what are the potential relationships between BMI group decision-making and managers' risk willingness? A thematic analysis based on Gioia's guidelines was conducted to identify themes in the comprehensive dataset.
Findings
First, the results show four typical group biases in BMI group decisions: Groupthink, social influence, hidden profile and group polarization. Findings show that the hidden profile paradigm and groupthink theory are essential in the context of BMI decisions. Second, we developed a BMI decision matrix, including the following key characteristics of BMI group decision-making managerial cohesion, conflict readiness and information- and emotion-based decision behavior. Third, in contrast to previous literature, we found that individual risk aversion can improve the quality of BMI decisions.
Practical implications
This paper provides managers with an opportunity to become aware of group biases that may impede their strategic BMI decisions. Specifically, it points out that managers should consider the key cognitive constraints due to their interactions when making BMI decisions. This work also highlights the importance of risk-averse decision-makers on boards.
Originality/value
This qualitative study contributes to the literature on decision-making by revealing key cognitive group biases in strategic decision-making. This study also enriches the behavioral science research stream of the BMI literature by attributing a critical influence on the quality of BMI decisions to managers' group interactions. In addition, this article provides new perspectives on managers' risk aversion in strategic decision-making.
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Ahmet Turgut and Begum Korunur Engiz
Currently, massive multiple-input multiple-output (m-MIMO) antennas are typically designed using complex trial-and-error methods. The purpose of this study is to determine an…
Abstract
Purpose
Currently, massive multiple-input multiple-output (m-MIMO) antennas are typically designed using complex trial-and-error methods. The purpose of this study is to determine an effective optimization method to achieve more efficient antenna design processes.
Design/methodology/approach
This paper presents the design stages of a m-MIMO antenna array compatible with 5G smartphones operating in long term evolution (LTE) bands 42, 43 and 46, based on a specific algorithm. Each antenna element in the designed 10-port m-MIMO antenna array is intended to perfectly cover the three specified LTE bands. The optimization methods used for this purpose include the Nelder–Mead simplex algorithm, covariance matrix adaptation evolution strategy, particle swarm optimization and trust region framework (TRF).
Findings
Among the primary optimization algorithms, the TRF algorithm met the defined objectives most effectively. The achieved antenna efficiency values exceeded 60.81% in the low band and 68.39% in the high band, along with perfect coverage of the desired bands, demonstrating the success of the design with the TRF algorithm. In addition, the potential electromagnetic field exposure caused by the designed m-MIMO antenna array is elaborated upon in detail using computational human models through specific absorption rate analysis.
Originality/value
The comparison of four different algorithms (two local and two global) for use in the design of a 10-element m-MIMO antenna array with a complex structural configuration and the success of the design implemented with the selected algorithm distinguish this study from others.
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