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…
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
Keywords
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…
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
Keywords
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
Keywords
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…
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
Keywords
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…
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.