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Article
Publication date: 9 December 2019

Mengjiao Wang, Yunxia Wang, Hao Liu and Fengyuan Yan

This paper aims to study the influence of load and environment medium on the fretting behavior of SAF 2507 SDSS.

Abstract

Purpose

This paper aims to study the influence of load and environment medium on the fretting behavior of SAF 2507 SDSS.

Design/methodology/approach

In this study, the effect of load on the fretting behavior of SAF 2507 SDSS in air and sea water were studied. The fretting wear tests under different loads were conducted with a ball-on-flat contact configuration. The friction coefficient, wear volume, surface morphology and oxidation component were determined.

Findings

With the increase of applied load, the friction coefficient decreases both in air and sea water. The fretting mechanism is gradually transformed from partial slip regime to slip regime in air while the fretting counterparts are all in the state of gross slip in sea water. In sea water, the friction coefficient is lower while the wear loss is higher compared with that in air.

Research limitations/implications

This research suggests that the fretting behavior of SAF 2507 SDSS is related to load and environment medium.

Practical implications

The results may help us to choose the appropriate load under different environments.

Originality/value

The main originality of the research is to reveal the fretting behavior of SAF 2507 SDSS under different loads in air and sea water, which would help us to realize fretting behavior of SAF 2507 SDSS is controlled by the combination of applied load and lubricating environment.

Peer review

The peer review history for this article is available at: http://dx.doi.org/10.1108/ILT-08-2019-0335.

Details

Industrial Lubrication and Tribology, vol. 72 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 13 May 2019

Mengjiao Guo, F. Sun and Zuozhu Yin

This paper used a novel technique, which is thermo-compression bonding, and Sn-1.0Ag-0.5Cu solder to form a full intermetallic compound (IMC) Cu3Sn joints (Cu/Cu3Sn/Cu…

Abstract

Purpose

This paper used a novel technique, which is thermo-compression bonding, and Sn-1.0Ag-0.5Cu solder to form a full intermetallic compound (IMC) Cu3Sn joints (Cu/Cu3Sn/Cu joints). The purpose of the study is to form high-melting-point IMC joints for high-temperature power electronics applications. The study also investigated the effect of temperature gradient on the microstructure evolution and the growth behavior of IMCs.

Design/methodology/approach

In this paper, the thermo-compression bonding technique was used to form full Cu3Sn joints.

Findings

Experimental results indicated that full Cu/Cu3Sn/Cu solder joints with the thickness of about 5-6 µm are formed in a short time of 9.9 s and under a low pressure of 0.016 MPa at 450°C by thermo-compression bonding technique. During the bonding process, Cu6Sn5 grew with common scallop-like shape at Cu/SAC105 interfaces, which was followed by the growth of Cu3Sn with planar-like shape between Cu/Cu6Sn5 interfaces. Meanwhile, the morphology of Cu3Sn transformed from a planar-like shape to wave-like shape until full IMCs solder joints were eventually formed during thermo-compression bonding process. Asymmetrical growth behavior of the interfacial IMCs was also clearly observed at both ends of the Cu/SAC105 (Sn-1.0Ag-0.5Cu)/Cu solder joints. Detailed reasons for the asymmetrical growth behavior of the interfacial IMCs during thermo-compression bonding process are given. The compound of Ag element causes a reduction in Cu dissolution rate from the IMC into the solder solution at the hot end, inhibiting the growth of IMCs at the cold end.

Originality/value

This study used the thermo-compression bonding technique and Sn-1.0Ag-0.5Cu to form full Cu3Sn joints.

Details

Soldering & Surface Mount Technology, vol. 31 no. 4
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 21 April 2020

Qian Wang and Jiajun Liu

The purpose of this paper is to explore an innovative teaching design to teach accounting management that aims to foster students’ technical and soft skills. The…

Abstract

Purpose

The purpose of this paper is to explore an innovative teaching design to teach accounting management that aims to foster students’ technical and soft skills. The effectiveness of this new teaching design addresses current concerns for universities preparing students for the future.

Design/methodology/approach

The paper deploys the qualitative research methodology and applies multiple methods to gather data in a case study. The researchers collected data through pre- and post-surveys of individual students, three half-day observations on the five project teams and a one-hour long semi-structured interview with a focus group.

Findings

Five themes emerged in the research to support the effectiveness of the new teaching design. The study also showed that students’ abilities in self-directed learning (SDL) link to their learning experiences. When students were more capable of initiating learning, such ability enriched their practices of soft skills in the team setting.

Research limitations/implications

This one-shot study had a small group of homogeneous participants and had no baseline comparison to identify the increment of students’ soft skills.

Practical implications

The findings provide valuable insights into the course design and implementation of the teaching approach for the future. The paper suggests that fostering students’ SDL will increase the effectiveness of soft skills development.

Originality/value

This empirical research extends current knowledge of teaching soft skills and calls for action on the development of students’ SDL abilities.

Details

On the Horizon, vol. 28 no. 2
Type: Research Article
ISSN: 1074-8121

Keywords

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Article
Publication date: 3 September 2020

Morteza Jamshidi, Heydar Dashti NaserAbadi and Mohammadreza Oliaei

The high heat induced by fire can substantially decrease the load-bearing capacity, which is more critical in unprotected steel structures than concrete reinforced…

Abstract

Purpose

The high heat induced by fire can substantially decrease the load-bearing capacity, which is more critical in unprotected steel structures than concrete reinforced structures. One of the conventional steel structures is a steel-plate shear wall (SPSW) in which thin infill steel plates are used to resist against the lateral loads. Due to the small thickness of infill plates, high heat seems to dramatically influence the lateral load-bearing capacity of this type of structures. Therefore, this study aims to provide an investigation into the performance of SPSW with reduced beam section at high temperature.

Design/methodology/approach

In the present paper, to examine the seismic performance of SPSW at high temperature, 48 single-span single-story steel frames equipped with steel plates with the thicknesses of 2.64 mm, 5 mm and 7 mm and yield stresses of 85 MPa, 165 MPa, 256 MPa and 300 MPa were numerically modeled. Furthermore, their behavioral indices, namely, strength, stiffness, ductility and hysteresis behavior, were studied at the temperatures of 20, 458, 642 and 917? The simulated models in the present paper are based on the experimental specimen presented by Vian and Bruneau (2004).

Findings

The obtained results revealed that the high heat harshly diminishes the seismic performance of SPSW so that the lateral strength is reduced even by 95% at substantially high temperatures. Therefore, SPSW starts losing its strength and stiffness at high temperature such that it completely loses its capacity of strength, stiffness and energy dissipation at the temperature of 917? Moreover, it was proved that by separating the percentage of their participations variations of the infill plate in SPSW, their behavior and the bare frame can be examined even at high temperatures.

Originality/value

To the best of the authors’ knowledge, the seismic performance of SPSW at different temperatures has not been evaluated and compared yet.

Details

Journal of Structural Fire Engineering, vol. 11 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

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