The present study aims to find out the best polymer/polymer pair in electrical insulating applications. Moreover, the effects of different polymer counterpart and applied load on…
Abstract
Purpose
The present study aims to find out the best polymer/polymer pair in electrical insulating applications. Moreover, the effects of different polymer counterpart and applied load on the friction and wear behaviour of PA 46 + 30%GFR and unfilled PA 66 thermoplastic polymers are to be studied.
Design/methodology/approach
Friction and wear tests vs PA 46 + 30%GFR and PPS + 30%GFR polymer composites were carried out on a pin‐on‐disc arrangement and at a dry sliding conditions. Tribological tests were performed at room temperature under 20, 40 and 60 N loads and at 0.5 m/s sliding speed.
Findings
The results showed that, the coefficient of friction decreases with the increasing of load (up to 40 N) for PA 46 + 30%GFR composite and polyamide (PA) 66 polymer used in this study. However, above 40 N applied load the coefficient of friction increases. The specific wear rate for PA 46 + 30%GFR and PA 66 against PPS + 30%GFR polymer composite counterpart are about in the order of 10−13 m2/N while the specific wear rate for PA 46 + 30%GFR and PA 66 against PA 46 + 30%GFR polymer composite counterpart are in the order of 10−14 m2/N. For PA 46 + 30%GFR composite and unfilled PA 66 polymers tested the specific wear rate values increased with the increment of load. The highest specific wear rate is for unfilled PA 66 against PPS + 30%GFR with a value of 2.81 × 10−13 m2/N followed by PA 66 against PA 46 + 30%GFR with a value of 2.26 × 10−13 m2/N. The lowest wear rate is PA 46 + 30%GFR polymer composite against PA 46 + 30%GFR polymer composite counterpart with a value of 3.19 × 10−14 m2/N. The average specific wear rates for unfilled PA 66 against PA 46 + 30%GFR is 80 times higher than PA 46 + 30%GFR wear rate while specific wear rates for unfilled PA 66 against PPS + 30%GFR is 100 times higher than that of PA 46 + 30%GFR wear rate. From point view of tribological performance, PA 46 + 30%GFR is a more suitable engineering thermoplastic composite materials for electrical contact breaker applications.
Research limitations/implications
In the present work, tribological tests were performed only at room temperature under three different loads and a sliding speed. This is the limitation of the work.
Practical implications
This work is easily used for industrial polyamides to check their tribological behaviours.
Originality/value
This is an original and experimental study and it will be useful both for academicians and for industrial sides.
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Yanhong Yan, Chengwen Yang, Yanfei Zhou, Wenbin Dong, Pengjuan Yan and Zhining Jia
Previously, the effect of pore-forming agents on the properties of pore size and morphology was studied. In this paper, we determine the optimal combination of parameters by…
Abstract
Purpose
Previously, the effect of pore-forming agents on the properties of pore size and morphology was studied. In this paper, we determine the optimal combination of parameters by tensile strength and perform tribological tests with optimal combination of parameters.
Design/methodology/approach
In this paper, porous polyimide (PI) materials were fabricated using vacuum hot molding technology. The orthogonal experiment was designed to test the mechanical properties of porous PI materials with the process parameters and the content of pore-forming agent as the changing factors. The porous PI oil-bearing materials were obtained by vacuum immersion, and tribological test were carried out.
Findings
The results showed that porous PI oil-bearing materials are suitable for low-speed and low-load conditions. The actual value of the friction coefficient basically match with the theoretical value of the regression analysis, and the errors of the friction coefficient are within 10% and 3%, respectively, which proves that the method used in the study is feasible for the friction coefficient prediction.
Originality/value
In this paper, we have produced a new porous oil-bearing material with good tribological properties. This study can effectively predict the friction coefficient of PI porous material.
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Reviews literature on industrial choice, ethnography and flexible specialization. Investigates flexible specialization in more depth, claiming that before ethnographic description…
Abstract
Reviews literature on industrial choice, ethnography and flexible specialization. Investigates flexible specialization in more depth, claiming that before ethnographic description can be achieved, abstract simplifications and the choices facing businesses in the local community have to be overcome. Proposes two models for economic recovery – flexible specialization and multinational Keynesianism – and discusses the boundaries that both models impose. Explores the public sphere and enterprise culture, particularly in the UK. Warns of the dangers of ethnographic studies of communities, specifically the imposition of meaning onto communal exchanges. Talks also of social solidarity. Observes that the identification of a communal language and a common work culture is tricky but that ethnography has a role to play in establishing the meaning of flexible specialization in small business communities.
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Ahmet Aysan, Hasan Dincer, Ibrahim Musa Unal and Serhat Yüksel
The primary purpose is to empower financial institutions in AI integration decisions. By combining QSFS and the Golden Cut technique, the study establishes a robust foundation for…
Abstract
Purpose
The primary purpose is to empower financial institutions in AI integration decisions. By combining QSFS and the Golden Cut technique, the study establishes a robust foundation for assessing AI progress effects, aligning implementation with performance goals, and promoting technical innovation. Dimensions explored include AI-related workforce competency, technological adaption, and ethical AI practices, crucial components within the BSC framework for technological innovation.
Design/methodology/approach
This study employs a distinctive approach, integrating the Balanced Scorecard (BSC) framework with Quantum Spherical Fuzzy Sets (QSFS) and the Golden Cut approach to explore the dynamic landscape of AI deployment. The integration addresses uncertainties, enhancing impact assessment accuracy amid ambiguity associated with AI outcomes. QSFS and the Golden Cut technique together facilitate precise identification of thresholds and crucial values.
Findings
The research delves into the intricate relationship between enduring financial stability and AI progress, recognizing technology's crucial influence on financial decision-making. Findings underscore technology's significant impact on financial institutions' AI integration decisions. This novel approach provides a strong quantitative basis, offering insights into workforce competency, technological adaption, and ethical AI practices.
Research limitations/implications
Despite valuable contributions, the study acknowledges limitations, such as potential biases and generalizability concerns, emphasizing the need for cautious interpretation and suggesting future research directions. Recognizing the research's boundaries and complexities in studying AI deployment in financial institutions underscores the need for ongoing exploration.
Originality/value
The research's originality lies in presenting an innovative methodology, integrating BSC, QSFS, and the Golden Cut, providing a unique perspective for decision-making. Contributions extend beyond academia, offering practical insights to enhance AI strategic implementation in the financial industry. This novel approach enriches the technology and finance discourse, fostering theoretical and practical advancements.
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Huseyin Unal, Salih Hakan Yetgin, Yasin Yılmaz and Fehim Findik
This study aims to investigate the tribological performance of neat polyamide-imide (PAI) and PAI composite (PAI + 12% graphite + 3% polytetrafluoroethylene [PTFE]) under varying…
Abstract
Purpose
This study aims to investigate the tribological performance of neat polyamide-imide (PAI) and PAI composite (PAI + 12% graphite + 3% polytetrafluoroethylene [PTFE]) under varying mediums and conditions, including dry sliding, distilled water and seawater lubrication, to determine their suitability for high-stress applications.
Design/methodology/approach
Tribological tests were conducted using a pin-on-disc setup with AISI 316 L stainless steel (SS) as counterface. Experiments were carried out under loads of 150 and 300 N and sliding speeds of 1.5 and 3.0 m/s. Values of temperatures, friction coefficients and wear rates were recorded to analyze the effect of fillers and lubrication mediums.
Findings
The PAI composite outperformed the neat PAI under all conditions, showing significant reductions in friction coefficients and wear rates. Seawater lubrication yielded the best results, achieving friction coefficients of 0.05 and 0.01 and specific wear rates of 18.10−16 m²/N and 1.10 −15 m²/N, for neat PAI and PAI composite, respectively. Graphite and PTFE fillers enhanced lubrication, reduced surface temperatures and mitigated abrasive and adhesive wear mechanisms. Superior cooling and lubrication effects of the seawater contributed to these improvements.
Originality/value
Previous studies mainly focused on dry sliding and distilled water lubrication for the PAI and its composites, with no research on the seawater conditions. This study compares the tribological behaviors of the neat PAI and PAI composite against AISI 316 L SS under dry sliding, distilled water and seawater lubrication.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0302/
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This paper reviews experience with credit union demutualisation to date in the light of increasing discussion about whether demutualisation is a likely (or inevitable) future…
Abstract
This paper reviews experience with credit union demutualisation to date in the light of increasing discussion about whether demutualisation is a likely (or inevitable) future stage in the evolutionary process. It is argued that the credit union industry faces an inherent demutualisation bias which emerges as the sector develops maturity. Contributing factors include the emergence of professional management pursuing personal objectives, together with the economic realities of technological change, financial liberalisation, increased competition, and prudential regulation based on minimum capital requirements. Demutualisation incentives may partially reflect the unsuitability of the mutual form of governance in larger, more sophisticated financial institutions, but there is also a significant risk of demutualisation based on wealth expropriation motives. Alternative policies and strategies which might avoid this demutualisation bias are examined.
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Muneer Umar, Michael Ikpi Ofem, Auwal Sani Anwar and Abubakar Garba Salisu
This study aims to fabricate and study the effect of five cumulative graphite (G) and graphite nanoplatelets (GNP) filler loading composites by polymerising PA6 precursor; monomer…
Abstract
Purpose
This study aims to fabricate and study the effect of five cumulative graphite (G) and graphite nanoplatelets (GNP) filler loading composites by polymerising PA6 precursor; monomer epsilon caprolactam with the two carbons in situ while taking cognisance of the mixing effects (simultaneous stirring and sonication at varying amplitudes and duration). Different aspect ratios will be used to model the two streams of polymerisations.
Design/methodology/approach
High viscosity extrusion grade PA6 and synthetic G of less than 2 µm particle size were used as fillers. GNP and G are dried for 6 h in vacuum oven at 90°C. Prior to in situ polymerisation, probe sonication was applied to disperse fillers in molten ɛ-caprolactam, the PA6 monomer. Five carbon loadings were made, that is 5–25 Wt.% for G and 0.5–2.5 Wt.% for GNP composites. Two different sonification regimes were applied 20% sonication amplitude for 20 min (20/20) and 40% sonication amplitude for 10 min (40/10).
Findings
Better tensile properties were achieved using the 20/20 processing streams for both G and GNP. The G- and the GNP-based composites systems of the 20/20 processing stream had tensile modulus and yield strength retained or improved above the unfilled PA6 value. The highest modulus obtained in the 20/20 streams are 1,878 and 1,201 MPa, respectively, for GNP and G at the highest loading levels, while the 40/10 processing streams had 963 and 1,247 MPa, respectively, for the GNP and G.
Originality/value
To the best of the authors’ knowledge, nobody has ever used sonification amplitude to compare mechanical properties.