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Article
Publication date: 15 August 2016

Lei Yan, Xueyang Chen, Wei Li, Joseph Newkirk and Frank Liou

This paper aims to achieve Ti-6Al-4V from Ti, Al and V elemental powder blends using direct laser deposition (DLD) and to understand the effects of laser transverse speed and…

604

Abstract

Purpose

This paper aims to achieve Ti-6Al-4V from Ti, Al and V elemental powder blends using direct laser deposition (DLD) and to understand the effects of laser transverse speed and laser power on the initial fabrication of deposit’s microstructure and Vickers hardness.

Design/methodology/approach

Two sets of powder blends with different weight percentage ratio for three elemental powder were used during DLD process. Five experiments with different processing parameters were performed to evaluate how microstructure and Vickers hardness change with laser power and laser transverse speed. Energy dispersive X-ray spectroscopy, optical microscopy and Vickers hardness test were used to analyze deposits’ properties.

Findings

This paper reveals that significant variance of elemental powder’s size and density would cause lack of weight percentage of certain elements in final part and using multiple coaxial powder nozzles design would be a solution. Also, higher laser power or slower laser transverse speed tend to benefit the formation of finer microstructures and increase Vickers hardness.

Originality/value

This paper demonstrates a new method to fabricate Ti-6Al-4V and gives out a possible weight percentage ratio 87:7:6 for Ti:Al:V at powder blends during DLD process. The relationship between microstructure and Vickers hardness with laser power and laser transverse speed would provide valuable reference for people working on tailoring material properties using elemental powder method.

Details

Rapid Prototyping Journal, vol. 22 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 23 September 2020

Lin Xueyang, Liu Rutie, Wang Lin, Li Zhengzhou, Xiong Xiang, Liao Ning and Chen Jie

This study aims to investigate the effect of combined use of granular graphite and petroleum coke on the properties of copper-based friction materials and the friction and wear…

465

Abstract

Purpose

This study aims to investigate the effect of combined use of granular graphite and petroleum coke on the properties of copper-based friction materials and the friction and wear mechanisms.

Design/methodology/approach

Copper-based friction materials with different proportions of petroleum coke and granular graphite were prepared by using powder metallurgy. The friction surfaces were analyzed.

Findings

Changing the ratio of petroleum coke/granular graphite affects the formation of oxides and sulfides on the surface of the materials. Increasing the petroleum coke promotes the production of metal sulfide and sulfate in the friction materials and reduces coefficient of friction (COF) and wear. Increasing petroleum coke also increases the amount of carbonic oxide (CO) released during the braking process and promotes the reduction process of iron oxide on the friction surface.

Originality/value

The synergistic effect of carbon materials on copper-based friction materials was studied in terms of the tribological chemical reaction. This research provides useful information for the selection of carbon materials in friction materials.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0075/

Details

Industrial Lubrication and Tribology, vol. 73 no. 1
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 26 May 2023

Supeng Zheng, Andrea Appolloni, Haifen Lin and Xiangan Ding

This paper aims to investigate the innovation pathway of gerontechnological enterprises under the market-organization-technology (MOT) perspective through configuration analysis.

185

Abstract

Purpose

This paper aims to investigate the innovation pathway of gerontechnological enterprises under the market-organization-technology (MOT) perspective through configuration analysis.

Design/methodology/approach

Based on the analytical framework of technology, organization and market, this paper conducts configuration analysis on the cases of 55 elderly-friendly enterprises in China combined with fuzzy-set qualitative comparative analysis (fsQCA).

Findings

First, this study identifies the three first-level preconditions affecting innovation performance: organization's architectural innovation, technology adapting to aging and market environment attention on the innovation pathway of gerontechnological enterprises. These three first-level conditions include six sub-conditions. Second, this study investigates three innovation pathways by analyzing the configuration effects of preconditions: Configuration 1, technology-balanced type; Configuration 2, organization-market linkage type and Configuration, 3 balanced type. Third, there are differences in the distribution of different configuration types in subdivided industries. The technology-balanced configuration is mainly concentrated in design-driven innovative enterprises, the organization-market linkage configuration is mainly concentrated in medical auxiliary equipment enterprises and the balanced configuration is mainly concentrated in smart elderly care service platform enterprises empowered by digital technology. Fourth, there are differences in the innovation impact paths of the same configuration type. However, the essence lies in the high-level innovation performance formed by the coordinated evolution of technology, organization and market factors, reflecting the characteristics of the same goal through different routes.

Research limitations/implications

The authors' study generates new insights for innovation managers of gerontechnological enterprises about the innovation pathway.

Originality/value

This research enriches innovation management by integrating the linkage adaptation relationship among market, organization and technology factors; further research studies on the different configuration types suitable for different types of enterprises, as well as differentiated innovation pathways under the same configuration type, could contribute to the study on the innovation pathway under a premise of MOT.

Details

European Journal of Innovation Management, vol. 27 no. 8
Type: Research Article
ISSN: 1460-1060

Keywords

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Article
Publication date: 12 January 2022

Marwa H. El-Azma, Nadia M. El-Beih, Karima A. El-Shamy, Khaled M.M. Koriem, Mahitab I. Elkassaby and Wael M. El-Sayed

This study aims to investigate the potential of pumpkin seed oil (PSO) and zinc to attenuate oxidative stress and neuroinflammation caused by chronic mild stress (CMS) in the…

242

Abstract

Purpose

This study aims to investigate the potential of pumpkin seed oil (PSO) and zinc to attenuate oxidative stress and neuroinflammation caused by chronic mild stress (CMS) in the cerebral cortex of male rats.

Design/methodology/approach

The rats were submitted to stress for six weeks and then the behavior of the rats was tested by forced swimming test (FST) and novel cage test. The treated groups were given venlafaxine (20 mg/kg), pumpkin seed oil (40 mg/kg) and zinc (4 mg/kg). The cortex homogenate was used for the detection of the oxidative stress parameters, the concentration of neurotransmitters, tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β), Na+/K+-ATPase activity, and the expression of histamine N-methyltransferase (Hnmt) and tyrosine hydroxylase (Th).

Findings

CMS causes a significant increase in immobility time in the FST and a significant decrease in the number of rearing in the novel cage test. CMS group showed a significant increase in alanine aminotransferase (ALT) activity, levels of cortisol, TNF-α, IL-1β, nitric oxide and malondialdehyde. CMS caused a significant decrease in the concentrations of serotonin, GABA, norepinephrine, and the activities of glutathione peroxidase, catalase, superoxide dismutase and Na+/K+-ATPase. CMS caused a marked reduction in the expression of Hnmt and Th in the cortex. PSO and zinc attenuated the Na+/K+-ATPase activity, oxidative parameters and neuroinflammation induced by the CMS, and this was reflected by the elevation of the concentration of neurotransmitters and reduction of cortisol and ALT, in addition to the behavior normalization. PSO and zinc attenuated the CMS by improving the antioxidant milieu and anti-inflammatory status of the cerebral cortex.

Originality/value

There are no studies on the effect of pumpkin seed oil on depression

Details

Nutrition & Food Science , vol. 52 no. 7
Type: Research Article
ISSN: 0034-6659

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