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Article
Publication date: 26 November 2018

Shaikh Asad Ali Dilawary, Amir Motallebzadeh, Muhammad Afzal, Erdem Atar and Huseyin Cimenoglu

The purpose of the study is to examine the sliding wear performance of plasma transfer arc (PTA) deposited and laser surface melted (LSM) Mo modified Stellite 12 hardfacings under…

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Abstract

Purpose

The purpose of the study is to examine the sliding wear performance of plasma transfer arc (PTA) deposited and laser surface melted (LSM) Mo modified Stellite 12 hardfacings under high contact stresses (i.e. >20 GPa).

Design/methodology/approach

For this purpose, after structural characterization, sliding wear tests have been conducted using sphero-conical diamond indenter as the counterface with different normal loads. The wear tracks formed on the hardfacings were examined by atomic force microscopy and scanning electron microscopy.

Findings

Both hardfacings showed severe wear (at high contact stress levels ranging from 24 to 41 GPa), which progressed by plastic deformation, although the wear resistance of LSMed hardfacings was better than the PTA hardfacings by a factor of two due to its near surface microstructure characterized as carbide-rich zone.

Originality/value

Sliding wear characterization of a promising 10 Wt.% Mo modified version of commercial Stellite 12 hardfacings (as reported previously by authors) was done in as PTA and LSMed states using nanomechanical test system. To the best of authors’ knowledge, no report is available in the open literature on such hardfacings under these testing conditions.

Details

Industrial Lubrication and Tribology, vol. 72 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 13 June 2016

Amir Motallebzadeh, Erdem Atar and Huseyin Cimenoglu

This paper aims to study microstructure and high temperature tribological performance of hypo-eutectic CoCrWC hardfacing alloy (Stellite 12) deposited on steel substrate by…

283

Abstract

Purpose

This paper aims to study microstructure and high temperature tribological performance of hypo-eutectic CoCrWC hardfacing alloy (Stellite 12) deposited on steel substrate by plasma-transferred arc (PTA) welding technique.

Design/methodology/approach

Microstructural characterization of the deposited coating was made using electron probe microanalysis, X-ray diffraction and microhardness tester. Dry sliding wear tests were carried out with a ball-on-disc type tribometer at room and elevated temperature. Worn surfaces of the samples were examined by the EDX equipped SEM and Raman spectroscopy.

Findings

Results revealed that at room temperature and 300°C plasticity dominated wear mechanism was operative. Under oxidation dominated wear conditions (400, 500, 600 and 700°C), testing temperature plays a crucial role on the characteristics of the oxide tribolayers formed on worn surfaces. Development of Cr2O3 in the tribolayer at 600 and 700°C was beneficial in increasing wear resistance of examined coating.

Originality/value

While the sliding wear performance of Stellite alloys at room temperature has been investigated in details, published studies on tribological behavior of Stellite alloys with varying temperature are scarce. Therefore, the present work was undertaken to study the wear mechanisms and the type of tribolayers formed during sliding wear of PTA welding deposited hypo-eutectic Stellite 12 coating with increasing temperature up to 700°C.

Details

Industrial Lubrication and Tribology, vol. 68 no. 4
Type: Research Article
ISSN: 0036-8792

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Book part
Publication date: 14 December 2023

Cahit Erdem and Mustafa Polat

This study aims to discover the general trends, the structural characteristics of the knowledge base, and developments in the field of internationalization of higher education…

Abstract

This study aims to discover the general trends, the structural characteristics of the knowledge base, and developments in the field of internationalization of higher education (IHE) in Turkey. In this respect, the studies published in journals indexed by SSCI, SCI-Expanded, ESCI, and AHCI in Web of Science (WoS) between January 1, 1975, and November 20, 2021, were analyzed. The dataset included 260 articles. We administered descriptive analysis reflecting the topographical features and the dynamics of the related literature through Excel and the WoS analysis tools. We conducted bibliometric analyses to shed light on the current view of the literature and reveal the intellectual structure of the knowledge base and topical foci. The volume of the research in the field of IHE in Turkey and their yearly distribution suggests that this area of research is still in its infancy; however, there has been a rapid growth in the number of publications recently. Author co-citation analysis reveals four distinct schools of thought labeled as “Higher Education Policy Studies in EU,” “Global Socio-politics and Economics of IHE,” “Socio-cultural and Psychological Dimensions of Internationalization” and “Language Studies.” Finally, topical foci in the knowledge base emerged as “International Student Mobility,” “Psychological and Cultural Adaptation of International Students,” “Higher Education Policy Reforms,” “International Staff Mobility” and “Migration Related Issues.” The results are discussed with related review studies and suggestions for future research are provided.

Details

Annual Review of Comparative and International Education 2022
Type: Book
ISBN: 978-1-83797-484-9

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Article
Publication date: 10 June 2021

Efecan Yar and Erdem Acar

The purpose of this paper is to find the optimum configuration of the composite launch tube currently being developed in Roketsan. The winding thicknesses and winding angles of…

123

Abstract

Purpose

The purpose of this paper is to find the optimum configuration of the composite launch tube currently being developed in Roketsan. The winding thicknesses and winding angles of the launch tube are selected as design variables, and three different composite material alternatives are evaluated: glass/epoxy, carbon/epoxy and aramid/epoxy.

Design/methodology/approach

In this study, structural optimization of a composite launch tube of man portable air defense system is conducted. To achieve a cost-effective design, a cost scoring table that includes structural weight, material cost, availability and manufacturability is first introduced. Then, optimization for minimum weight is conducted, where the winding thicknesses and winding angle are taken as design variables, and the safety factor value obtained by using the Tsai–Wu damage criterion is used as constraint. A surrogate-based optimization approach is used where various options for surrogate models are evaluated. Glass/epoxy, carbon/epoxy and aramid/epoxy are considered as alternative materials for the launch tube. Finally, the selection of the most cost-effective design is performed to achieve optimum cost.

Findings

Carbon fiber-reinforced epoxy matrix material provides the optimum cost-effective design for the launch tube.

Practical implications

The findings of the paper can be used to design more cost-efficient composite launch tube currently being developed in Roketsan.

Originality/value

The existing studies are based on a design approach to achieve minimum weight of the launch tubes, whereas this study introduces a design approach to achieve optimum cost.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 5
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 23 May 2024

Abhinandan Kulal, Abhishek Nanjundaswamy, Sahana Dinesh, Neethu Suraj and N. Mallika

The present research aimed to examine the role of FDP in enhancing the teachers' competencies through modern technological tools and innovative teaching methods. And also, to…

115

Abstract

Purpose

The present research aimed to examine the role of FDP in enhancing the teachers' competencies through modern technological tools and innovative teaching methods. And also, to evaluate the impact of FDPs on teachers' attitudes and motivation to integrate modern teaching innovations into their classroom practices.

Design/methodology/approach

Using a pre-post study design, the study was conducted in two phases, Phase I was conducted one week before conducting FDP (14th to 20th August 2023) and Phase II was conducted after one week of FDP (15th to 21st September 2023). The data were gathered through structured questionnaires from the participants in FDP and collected data were processed and analyzed through a statistical package for social sciences.

Findings

The study found that undergoing FDP by teachers significantly influences the adoption of advanced pedagogical approaches and technology integration during their teaching practice. This indirectly helps in promoting quality education at large and contributes to the UNSDG-4. The study also revealed that the effective FDP not only helps in advancing teaching methods but also influences instructors' philosophies and attitudes towards students' overall learning and development.

Practical implications

These findings have several key implications for higher education institutions, policymakers and teachers at large. Firstly, HEIs should prioritize undertaking FDPs that promote in adopting advanced pedagogical approaches. This indirectly equips the instructors with the knowledge and skills necessary to integrate modern teaching methods into their real classroom practices. Further, by adopting FDP as a strategic initiative to improve the quality of education and work by aligning these programs with broader SDG goals.

Originality/value

Advancing education for enhancing the overall quality of learning depends on the competencies of instructors. The competencies of instructors rely upon the involvement of instructors in life-long learning, level of adoption of technology, innovative approaches used, etc. This study may help higher education institutions adopt FDP as a strategic initiative to improve the quality of education and work by aligning these programs with broader SDG goals.

Details

Journal of Applied Research in Higher Education, vol. 16 no. 4
Type: Research Article
ISSN: 2050-7003

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