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Article
Publication date: 30 August 2022

Yan Zhang, Xianghu Ge, Xin Zhao, Xiaorui Yang, Shanghe Liu and Jingjing Xuan

The purpose of this paper is to research the induced flashover laws of different insulation materials under electrostatic electromagnetic pulse, and the induced flashover…

Abstract

Purpose

The purpose of this paper is to research the induced flashover laws of different insulation materials under electrostatic electromagnetic pulse, and the induced flashover characteristics of different electrode structures are further explored.

Design/methodology/approach

According to standard IEC 61000–4-2, an experimental system of electrostatic electromagnetic pulse flashover for insulation materials is established. The induction flashover laws of polytetrafluoroethylene, epoxy resin and polymethyl methacrylate surface-mounted finger electrodes under the different intensity of electrostatic electromagnetic pulse are researched. The influence of the finger electrode, needle–needle electrode and needle–plate electrode on insulation flashover was compared. Secondary electron emission avalanche (SEEA) and field superposition theory are used to analyze the experimental results of electrostatic electromagnetic pulse induced flashover.

Findings

The larger the dielectric strength of insulation materials, the more difficult flashover occurs on the surface. The field superposition enhances collision ionization between electrons and gas molecules, which leads to the insulation materials surface induced flashover easily by electrostatic electromagnetic pulse. The sharper the electrode shapes on the insulation materials surface, the stronger the electric field intensity at the cathode triple junction, more initial electrons are excited to form the discharge channel, which easily leads to flashover on the surface of the insulating material.

Originality/value

The proposed field superposition combined with the SEEA method provides a new study perspective and enables a more rational, comprehensive analysis of electrostatic electromagnetic pulse induced flashover of insulation materials. The work of this paper can provide a reference for the safety protection of spacecraft in orbit under a strong electromagnetic field environment, increase the service life of spacecraft and improve the reliability of spacecraft’s safe operation in orbit. It provides a basis for the selection of insulation materials for equipment under the different intensities of the external electromagnetic environment.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 30 November 2022

Sarita Bharti and Senthilvelan Selvaraj

This paper aims to understand the effect of the manufacturing process on the frictional and wear performance of polyamide.

Abstract

Purpose

This paper aims to understand the effect of the manufacturing process on the frictional and wear performance of polyamide.

Design/methodology/approach

Pin specimens were manufactured through injection moulding (IM) and selective laser sintering (SLS) manufacturing processes. The friction and wear performance was evaluated using a pin-on-disc configuration under dry and oil-lubricated conditions. The friction coefficient, wear resistance and surface temperature of specimens were measured, and failure morphology analysis was carried out to understand the mechanism.

Findings

SLS material exhibited significantly less friction, wear and surface temperature than IM material under dry conditions. Reduced ductility due to the sintering contributes to reduced friction, wear and heat generation. Under the dry condition, IM material exhibited plastic flow and roll-shaped deformation, whereas SLS material exhibited only local degradation due to its lesser ductility. Lubrication reduced friction and temperature for both SLS and IM materials. The porous nature of the sintered surface absorbed the lubricant and released it while sliding, which is confirmed by the brown-coloured wear track.

Originality/value

The study provides valuable input to the designers on the sliding contact performance of commonly adopted two different manufacturing processes of polymers; IM and SLS manufacturing.

Details

Industrial Lubrication and Tribology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 15 November 2022

Qingyang Liu, Ziyang Zhang, Denizhan Yavas, Wen Shen and Dazhong Wu

Understanding the effect of process parameters on interfaces and interfacial bonding between two materials during multi-material additive manufacturing (MMAM) is crucial…

Abstract

Purpose

Understanding the effect of process parameters on interfaces and interfacial bonding between two materials during multi-material additive manufacturing (MMAM) is crucial to the fabrication of high-quality and strong multi-material structures. The purpose of this paper is to conduct an experimental and statistical study to investigate the effect of process parameters of soft and hard materials on the flexural behavior of multi-material structures fabricated via material extrusion-based MMAM.

Design/methodology/approach

Sandwich beam samples composed of a soft core and hard shells are fabricated via MMAM under different printing conditions. A design of experiments is conducted to investigate the effect of the print speed and nozzle temperature on the flexural behavior of soft-hard sandwich beams. Analysis of variance and logistic regression analysis are used to analyze the significance of each process parameter. The interfacial morphology of the samples after the flexural tests is characterized. Thermal distributions during the MMAM process are captured to understand the effect of process parameters on the flexural behavior based on inter-bonding formation mechanisms.

Findings

Experimental results show that the soft-hard sandwich beams exhibited two different failure modes, including shell failure and interfacial failure. A transition of failure modes from interfacial failure to shell failure is observed as the nozzle temperatures increase. The samples that fail because of interfacial cracking exhibit a pure adhesive failure because of weak interfacial fracture properties. The samples that fail because of shell cracking exhibit a mixed adhesive and cohesive failure. The flexural strength and modulus are affected by the nozzle temperature for the hard material and the print speeds for both hard and soft materials significantly.

Originality/value

This paper first investigates the effect of process parameters for soft and hard materials on the flexural behavior of additively manufactured multi-material structures. Especially, the ranges of the selected process parameters are distinct, and the effect of all possible combinations of the process parameters on the flexural behavior is characterized through a full factorial design of experiments. The experimental results and conclusions of this paper provide guidance for future research on improving the interfacial bonding and understanding the failure mechanism of multi-material structures fabricated by MMAM.

Details

Rapid Prototyping Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 8 September 2022

Xie Yidong, Sun Peiweni, Li Qiang, Fu Caozheng, AiHua Zhu, Jianwei Yang and Chaochao Ma

The CL60 steel wheels of metro vehicles running on a specific line need frequent reprofiling due to rapid wear. Considering this problem, a new material for metro wheels…

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Abstract

Purpose

The CL60 steel wheels of metro vehicles running on a specific line need frequent reprofiling due to rapid wear. Considering this problem, a new material for metro wheels was designed. The friction and wear properties of the new material were studied, to reduce the wear rate and extend the service life of metro wheels.

Design/methodology/approach

Wheel specimens made of the two steel materials were tested using a GPM-60 wear tester under laboratory conditions. A field test was conducted on a specific metro line to track the wear in wheels made of the new material and CL60 steel wheels.

Findings

Under the laboratory conditions, the wear loss in the new material was 24.44% lower than that in CL60 steel. The field test revealed that compared to CL60 steel wheels, the new CL60 steel wheels showed a 19.42% decrease in tread wear on average. The field measurements for the wheels made of the new material are consistent with the results of laboratory simulation, suggesting relatively high wear resistance of the new material.

Practical implications

The results of the study can provide guidance on how to properly select steel material for metro wheels to avoid rapid wear and frequent reprofiling and reduce operating costs.

Originality/value

A new material for metro wheels was designed and developed by optimizing the content of Cr, Si, Mn, V and other elements. This material proved to have better wear resistance in both laboratory and field testing.

Details

Industrial Lubrication and Tribology, vol. 74 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 23 September 2022

Visar Hoxha and Veli Lecaj

The purpose of this paper is to highlight the regulatory barriers to achieving sustainable buildings in Kosovo. The present paper focuses on regulatory barriers viewed…

Abstract

Purpose

The purpose of this paper is to highlight the regulatory barriers to achieving sustainable buildings in Kosovo. The present paper focuses on regulatory barriers viewed from the perspective of construction industry experts in achieving sustainable buildings.

Design/methodology/approach

The present study uses a qualitative research method and semi-structured interviews as a research instrument. The present study interviews around 20 experts in construction and property management, property development, spatial planning and energy management.

Findings

The study finds that Kosovo building laws and regulations provide for the materials assessment criteria, but the materials assessment criteria are only for mechanic strength. The study further finds that the sustainability concept is not included and incorporated in Kosovo's urban planning laws and regulations. The study also finds that despite specific clauses mentioning energy performance certificates in the Law on Energy Performance of Buildings in Kosovo, energy performance certificates appears to be not enforced and the nature of the barrier is more organizational rather than regulatory. Finally, the study finds that Kosovo laws are silent as far as green labeling of building materials is concerned.

Practical implications

The implication of the present finding is that policymakers in Kosovo not only should include clear sustainable materials assessment criteria in the law, but also enforce those criteria through testing and inspection mechanisms included in the law and implemented in practice through funding and organizational support. Nonetheless, policymakers in Kosovo should contemplate amending the urban planning laws in Kosovo and include both the term of sustainability at the planning level and conformity guidelines for sustainable design that can be done at the administrative directive level. Further, the clauses in the law do not suffice if the clauses are not accompanied by specific systemic and organizational support in the issuance of energy performance certificates. Policymakers in Kosovo should be proactive in designing clauses that specify green labeling standards for materials; however, these labeling standards should not adversely affect the cost of construction and reduce the demand for real estate.

Originality/value

The study is the first qualitative study about the perception of construction professionals in Kosovo, regarding the regulatory barriers of sustainable buildings in Kosovo.

Details

Property Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0263-7472

Keywords

Article
Publication date: 11 October 2022

Deena El-Mahdy, Hisham S. Gabr and Sherif Abdelmohsen

Despite the dramatic increase in construction toward additive manufacturing, several challenges are faced using natural materials such as Earth and salt compared to the…

Abstract

Purpose

Despite the dramatic increase in construction toward additive manufacturing, several challenges are faced using natural materials such as Earth and salt compared to the most market-useable materials in 3D printing as concrete which consumes high carbon emission.

Design/methodology/approach

Characterization and mechanical tests were conducted on 19 samples for three natural binders in dry and wet tests to mimic the additive manufacturing process in order to reach an efficient extrudable and printable mixture that fits the 3D printer.

Findings

Upon testing compressive strength against grain size, compaction, cohesion, shape, heat and water content, X-Salt was shown to record high compressive strength of 9.5 MPa. This is equivalent to old Karshif and fire bricks and surpasses both rammed Earth and new Karshif. Material flow analysis for X-Salt assessing energy usage showed that only 10% recycled waste was produced by the end of the life cycle compared to salt.

Research limitations/implications

Findings are expected to upscale the use of 3D salt printing in on-site and off-site architectural applications.

Practical implications

Findings contribute to attempts to resolve challenges related to vernacular architecture using 3D salt printing with sufficient stability.

Social implications

Benefits include recyclability and minimum environmental impact. Social aspects related to technology integration remain however for further research.

Originality/value

This paper expands the use of Karshif, a salt-based traditional building material in Egypt's desert by using X-Salt, a salt-base and natural adhesive, and investigating its printability by testing its mechanical properties to reach a cleaner and low-cost sustainable 3D printed mixture.

Details

Smart and Sustainable Built Environment, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2046-6099

Keywords

Article
Publication date: 1 July 2021

Arun M., Muthukumaran M. and Balasubramanian S.

Dissimilar materials found applications in the structural fields to withstand the different types of loads and provide multi-facet properties to the final structure…

Abstract

Purpose

Dissimilar materials found applications in the structural fields to withstand the different types of loads and provide multi-facet properties to the final structure. Aluminum alloy materials are mostly used in aerospace and marine industries to provide better strength and safeguard the material from severe environmental conditions. The purpose of this study is to develop new material with superior strength to challenge the severe environmental conditions.

Design/methodology/approach

In the present investigation, friction stir welding (FSW) dissimilar joints were prepared from AA6061 and AA5083 aluminum alloys, and the weld nugget (WN) was reinforced with hard reinforcement particles such as La2O3 and CeO2. The tribological and mechanical properties of the prepared materials were tested to analyze the suitability of material in the aerospace and marine environmental conditions.

Findings

The results showed that the AA6061–AA5083/La2O3 material exhibited better mechanical and tribological characteristics. The FSW dissimilar AA6061–AA5083/La2O3 material exhibited lower wear rate of 7.37 × 10−3 mm3/m and minimum friction coefficient of 0.31 compared to all other materials owing to the reinforcing effect of La2O3 particles and the fine grains formed by FSW process at WN region. Further, FSW dissimilar AA6061–AA5083/La2O3 material displayed a maximum tensile strength and hardness of 378 MPa and 118 HV, respectively, among all the other materials tested.

Originality/value

This work is original and novel in the field of materials science engineering focusing on tribological characteristics of friction stir welded dissimilar aluminum alloys by the reinforcing effect of hard particles such as La2O3 and CeO2.

Details

Industrial Lubrication and Tribology, vol. 73 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 19 May 2021

Batuhan Özakın, Bilal Çolak and Naci Kurgan

The last stage of the cold rolling process is skin-pass rolling and one of its most significant goals is to obtain appropriate topography on the surface of the sheet steel…

Abstract

Purpose

The last stage of the cold rolling process is skin-pass rolling and one of its most significant goals is to obtain appropriate topography on the surface of the sheet steel used extensively such as in automotive industry. The purpose of this paper is to investigate the effect of thickness change and various reduction ratios on roughness transfer of DC04 grade sheet material.

Design/methodology/approach

DC04 grade sheet materials with different reduction ratios and several thicknesses were subjected to skin-pass rolling process in the rolling equipment with a two-high roll. Some roughness parameters were determined as a result of roughness measurements from the surfaces of roughened sheet materials.

Findings

While the roughness transfer is higher in 1-mm thick material in reduction ratios up to 430 micrometers; in reduction ratios above 430 micrometers, it is higher for 1.5-mm thick materials. As the reduction ratio increases in DC04 grade sheet materials, the homogeneity of the roughness distribution in 1-mm thickness sheet material deteriorates, while the roughness distribution in 1.5-mm thickness sheet material is more homogeneous.

Originality/value

This paper demonstrates how material thickness and reduction ratio affect the roughness transfer in skin-pass rolling. The results obtained can be used by optimizing in manufacturing processes.

Details

Industrial Lubrication and Tribology, vol. 73 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Book part
Publication date: 25 February 2011

Suzana Sukovic

This research paper explores the roles of electronic texts in research projects in the humanities and seeks to deepen the understanding of the nature of scholars'…

Abstract

This research paper explores the roles of electronic texts in research projects in the humanities and seeks to deepen the understanding of the nature of scholars' engagement with e-texts. The study used qualitative methodology to explore engagement of scholars in literary and historical studies with primary materials in electronic form (i.e., e-texts). The study revealed a range of scholars' interactions with e-texts during the whole research process. It uncovered a particular pattern of information-seeking practices in electronic environments called netchaining and the main types of uses and contributions of e-texts to research projects. It was found that e-texts play support and substantive roles in the research process. A number of influences from electronic environment are identified as challenges and aids in working with e-texts. The study does not have statistical significance. It indicates a need for further research into scholarly practices, training requirements, and new forms of service provision. Study results are relevant for the development of digital collections, information services, educational programs, and other forms of support for the use of technology in research. The results can be also used to inform approaches to text encoding and development of electronic information systems and have implications for organizational and industry policies. The study found a range of scholars' interactions and forms of intellectual engagement with e-texts that were not documented and analyzed by earlier studies. It provides insights into disciplinary variations in the humanities and contributes to the understanding of scholarly change catalyzed by information technology.

Details

Advances in Librarianship
Type: Book
ISBN: 978-0-85724-755-1

Book part
Publication date: 17 March 2010

Michaela DeSoucey and David Schleifer

This chapter addresses how small businesses resist city regulations by using material things, by making craft knowledge claims about material things, and by letting…

Abstract

This chapter addresses how small businesses resist city regulations by using material things, by making craft knowledge claims about material things, and by letting material things organize their political activity. Chefs successfully resisted a foie gras ban in Chicago, where political resistance shaped the production and use of material things. Bakers successfully resisted a trans fat ban in Philadelphia, where material properties of things structured political resistance. We bring together analytic tools from the sociology of culture and science and technology studies to demonstrate how materiality can be both an instigator and an instrument of legal and political resistance.

Details

Special Issue Interdisciplinary Legal Studies: The Next Generation
Type: Book
ISBN: 978-1-84950-751-6

1 – 10 of over 196000