Tribological properties of carbon nanotube grease

2014 ◽  
Vol 66 (5) ◽  
pp. 579-583 ◽  
Author(s):  
Liu Hongtao ◽  
Ji Hongmin ◽  
Hong Haiping ◽  
Hammad Younes
Keyword(s):  
Carbon Nanotube ◽  
Performance Improvement ◽  
Tribological Properties ◽  
Dry Friction ◽  
Design Methodology ◽  
Hexagonal Structure ◽  
Content Type ◽  
Base Oil ◽  
New Type ◽  
Lubricating Mechanism

Purpose – The purposes of this paper are to prepare the carbon nanotube (CNT) grease, to contrast the tribology properties of the CNT grease with the original grease and to find the lubricating mechanism of the CNT grease. Design/methodology/approach – The CNTs (single-wall and multi-wall) are added into the polyalphaolefin oils (DURASYN_166) to form stable and homogeneous CNT grease with potential heat transfer, conductive and lubricative properties. The friction of this new type of CNT grease was determined by wear experiments under three conditions: dry friction, with the base oil grease and with the CNT grease. Findings – The research is about the tribological properties of CNT greases; it shows better lubricating performance and wear resistance than the base oil grease. The performance improvement of CNT grease is owing to the unique hexagonal structure and the high thermal conductivity of CNTs. Originality/value – The paper documents that CNTs can obviously improve the lubricating effect of grease, and the lubricating mechanism of the CNT grease is also discussed.

Tribological properties of the epoxy resin-based solid lubricant coating modified by Kevlar fibers

2018 ◽  
Vol 70 (9) ◽  
pp. 1706-1713 ◽  
Author(s):  
Guotao Zhang ◽  
Yanguo Yin ◽  
Ting Xie ◽  
Dan Li ◽  
Ming Xu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Epoxy Resin ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Transfer Film ◽  
Wear Properties ◽  
Content Type ◽  
Friction And Wear Properties

Purpose This paper aims to obtain high mechanical and good tribological properties of epoxy resin-based coatings under dry friction conditions. Design/methodology/approach Bonded solid lubricant coatings containing Kevlar fibres were prepared by a spraying method. The friction and wear properties of the coatings were experimentally investigated with a face-to-face tribometre under dry friction conditions. Scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D laser scanning technologies were used to characterise the tribological properties. The action mechanism of the Kevlar fibres on a solid lubricant transfer film was also analysed. Findings Adding Kevlar fibres can significantly improve the wear resistance of the coatings. When the Kevlar fibre content increases, the tribological properties of the coatings improve and then worsen. Superior properties are obtained with 0.03 g of Kevlar fibres. Appropriately increasing the load or speed is beneficial to the removal of the outer epoxy resin and the formation of a lubricant film. During friction, the solid lubricants wrapped in the epoxy resin accumulate on the surface to form a transfer film that shows a good self-lubricating performance. In the later friction stage, fatigue cracks occur on the solid lubricant film but cannot connect to one another because of the high wear resistance and the entanglement of the rod-like Kevlar fibres. Thus, no large-area film falls from the matrix, thereby ensuring the long-term functioning of solid lubricant coatings. Originality/value Epoxy resin-based solid lubricant coatings modified by Kevlar fibres were prepared, and their friction and wear properties were investigated. Their tribological mechanisms were also proposed. This work provided a basis for the analysis of the tribological properties and design of bonded solid lubricant coatings containing Kevlar fibres.

Fraud and counterfeit wines in France: an overview and perspectives

2017 ◽  
Vol 119 (1) ◽  
pp. 84-104 ◽  
Author(s):  
Benoit Lecat ◽  
Joelle Brouard ◽  
Claude Chapuis
Keyword(s):  
Media Coverage ◽  
Design Methodology ◽  
Modern Technology ◽  
Wine Industry ◽  
Technological Changes ◽  
Content Type ◽  
New Type ◽  
Technical Solutions ◽  
Official Data ◽  
Practical Implications

Purpose The purpose of this paper is to analyze the specificities of wine forgery today and to show the perspectives offered to the different stakeholders in the wine industry. Design/methodology/approach Owing to the technical aspects of this paper, a literature review based on academic papers (history) and articles coming from the professional press, internet websites and public organizations was made. Findings It was found that frauds have always existed. Forgers are constantly in search of new ways of counterfeiting wines. Producers have had to adapt to the various forms of counterfeiting, mainly by resorting to modern technology. As the traceability of great wines is becoming crucial, a new type of relationships between producers anxious to offer genuine estate wines and consumers anxious to drink the bottles they ordered has developed. This new constraint became a marketing opportunity for producers. Research limitations/implications It was difficult to obtain official data (interviews or surveys) because of the sensitiveness of the topic. Practical implications This paper, which offers an inventory of the methods used by forgers to deceive customers, makes both producers and consumers aware of the extent of the problem. The counterfeiting phenomenon is dangerous for producers’ image and the technological changes are a tool allowing producers to protect their wine and reinforce their relationships with consumers. Originality/value This paper gives an overview of forgers’ ploys in France. It opens a discussion about perspectives for the different stakeholders while most of the research tends to focus on technical solutions and the analysis of specific affairs which received media coverage.

Local on-demand fabrication: microfactories and online manufacturing platforms

2020 ◽  
Vol 32 (1) ◽  
pp. 20-41
Author(s):  
Jose Orlando Montes ◽  
F. Xavier Olleros
Keyword(s):  
Design Methodology ◽  
Content Type ◽  
On Demand ◽  
Online Platforms ◽  
Machine Shops ◽  
Multiple Case ◽  
New Type ◽  
Experiential Research ◽  
Practical Implications

PurposeThis article explores a particular on-demand fabrication unit, the microfactory (MF). It identifies and contrasts several MFs and proposes a taxonomy. This research also explores online manufacturing platforms (OMP) that complement certain MFs.Design/methodology/approachThis research implements a multiple case study (71 cases in 21 countries), triangulating data available on the web with interviews, virtual/physical tours and experiential research.FindingsThe results suggest that automation and openness are the main dimensions that differentiate the MFs. Using these dimensions, a taxonomy of MFs is created. MFs with relatively low automation and high openness tend to be innovation-driven microfactories (IDMFs). MFs with high automation and low openness levels tend to be customization-driven microfactories (CDMFs). And MFs with relatively low automation and low openness tend to be classic machine shops (MSs). There are two types of OMP: closed (COMPs) and multisided (MOMPs). MOMPs can be low-end or high-end.Practical implicationsIn a world where online platforms are becoming central to the reinvention of manufacturing, multisided online platforms and small fabricators will become strongly symbiotic.Originality/valueThis paper offers a clearer conceptualization of MFs and OMPs, which may help to better understand the reality of local on-demand fabrication. Moreover, it explores a new type of experiential research, which tries to describe and interpret firms through transactional activities. Many details of a firm that are difficult to capture via interviews and netnography can be revealed this way.

The tribological performance of engineered micro-surface topography by picosecond laser on PEEK

2019 ◽  
Vol 72 (1) ◽  
pp. 172-179 ◽  
Author(s):  
Meiling Wang
Keyword(s):  
Tribological Properties ◽  
Design Methodology ◽  
Friction And Wear ◽  
Picosecond Laser ◽  
Wear Property ◽  
Content Type ◽  
Friction Curve ◽  
Micro Structures ◽  
Wear Tests ◽  
Friction And Wear Tests

Purpose The purpose of this study is to investigate the effect of engineered micro-structures on the tribological properties of metal-polyetheretherketone (PEEK) surface. Design/methodology/approach Circular dimples with diameters of 25 and 50 µm were designed and manufactured on PEEK plate specimens using picosecond laser. Reciprocating friction and wear tests on a ball-on-flat configuration were performed to evaluate the tribological properties of the designed micro-structures in dry contacts. The loading forces of 0.9 and 3 N were applied. Findings As a result, obvious fluctuations of coefficient of friction curve were observed in tribosystems consisting of non-textured and textured PEEK with circular dimples of 25 µm in diameter. GCr15 ball/textured PEEK plate specimens with circular dimples of 50 µm in diameter revealed a superior friction and wear property. Originality/value Different to the existing studies in which the tribopairs consist of hard bearing couples, this study investigated the tribological properties of the engineered micro-structures on the hard-on-soft bearing couples.

Synthesis and tribological properties of nanogrease

2018 ◽  
Vol 70 (3) ◽  
pp. 512-518 ◽  
Author(s):  
Alaa Mohamed ◽  
Mohamed Hamdy ◽  
Mohamed Bayoumi ◽  
Tarek Osman
Keyword(s):  
Electron Microscopy ◽  
Tribological Properties ◽  
Power Efficiency ◽  
New Technologies ◽  
Mechanical Equipment ◽  
Content Type ◽  
Base Oil ◽  
X Ray ◽  
Transmission Electron ◽  
Steel Balls

Purpose To enhance the tribological properties of nanogrease, one of the new technologies was used to synthesize a nanogrease having carbon nanotubes (CNTs) nanoparticles (NPs) with different concentrations. The microstructures of the synthesized NPs were characterized and evaluated by x-ray diffraction spectroscopy (XRD) and transmission electron microscopy (TEM). Tribological properties of the nanogrease were evaluated using a four-ball tester. The worn surface of four steel balls was investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). Design/methodology/approach Grease was dissolved in chloroform (10 Wt.%), at 25 °C for 1 h. In parallel, functionalized CNTs with different volume concentrations (0.5, 1, 2 and 3 Wt.%) were dispersed in N, N-dimethylformamide. The mixture was stirred for 15 min and then sonicated (40 kHz, 150 W) for 30 min. After that, the mixture was added to the grease solution and magnetically stirred for 15 min and then sonicated for 2 h. Findings The results suggested that CNTs can enhance the antiwear and friction properties of nanogrease at 0.5 Wt.% CNTs to about 57 and 48 per cent, respectively. In addition, the weld load of the base oil containing 0.5 Wt.% CNTs was improved by 17 per cent compared with base grease. Originality/value This work describes the inexpensive and simple fabrication of nanogrease for improving the properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Preparation and tribological properties of attapulgite – bentonite clay base grease

2014 ◽  
Vol 66 (4) ◽  
pp. 538-544 ◽  
Author(s):  
Tiedan Chen ◽  
Yanqiu Xia ◽  
Zhilu Liu ◽  
Zeyun Wang
Keyword(s):  
Tribological Properties ◽  
Bentonite Clay ◽  
Solid Particles ◽  
Lubricating Grease ◽  
Content Type ◽  
Base Oil ◽  
Dropping Point ◽  
Attapulgite Clay ◽  
Surface Modified ◽  
Base Grease

Purpose – The mixture of attapulgite and bentonite was used as a thickener, and polyalphaolefin was used as the base oil to prepare the new lubricating grease. Some solid particles such as Polytetrafluoroethene (PTFE), MoS2, nano-calcium carbonate and graphite were added in the new lubricating grease as anti-wear additives to investigate the tribological sensitivity. Design/methodology/approach – The new lubricating grease was evaluated by optimol-SRV reciprocating friction and wear tester, and the wear volumes were determined using a MicroXAM-3D. At the same time, the dropping point and the cone penetration were investigated and analyzed. The tribological properties of the new lubricating grease and the sensitivity of some solid lubricating additives to the new lubricating base grease were investigated; pure organic-bentonite and pure organic-attapulgite base grease were used as contrast. Findings – The new lubricating grease based on the surface-modified bentonite/attapulgite clay base grease was synthesized with a relatively high dropping point, and the mass ratio is 25/75 bentonite/attapulgite clay base grease, having a better tribological performance. MoS2 was used as an anti-wear additive that has good tribological sensitivity to the new lubricating base grease. Originality/value – The main innovative thought of this work lies in the mixture of attapulgite and bentonite used as thickener. A relevant report is not available at present.

Portraiture and social understanding

2015 ◽  
Vol 1 (1) ◽  
pp. 30-40
Author(s):  
Brooke Levin
Keyword(s):  
Design Methodology ◽  
Autism Spectrum ◽  
Controlled Environment ◽  
Social Understanding ◽  
Emotional Information ◽  
Content Type ◽  
Facial Stimuli ◽  
Potential Success ◽  
New Type ◽  
Core Issues

Purpose – The purpose of this paper is to discuss the possible explanations for deficits in social understanding evident in individuals with autism spectrum disorder (ASD). A potential intervention technique is proposed that has not yet been examined in this population: viewing and drawing portraits. This portraiture-based intervention seeks to address some of the core issues set forth in each of the theories explaining impaired social functioning. Furthermore, this intervention is intended to specifically increase exposure to facial stimuli in a safe and controlled environment. Instructions about how to look closely at a social partner’s face and how to glean salient emotional information from the facial expression displayed can be developed through a focused exploration of drawing and viewing portraits. Current techniques such as eye tracking and fMRI are discussed in the context of this proposed intervention. Design/methodology/approach – This paper reviews existing research about ASD and seeks to present a new proposal for an intervention using portraiture. First the paper discusses existing interventions and reviews the current research about potential causes/areas of deficiency in individuals on the spectrum. This paper subsequently proposes a new type of intervention and discusses the reasons underpinning its potential success in the context of existing research. Findings – This was a proposed study so no empirical findings have been reported. However, observations of individuals on the spectrum engaging with artwork are discussed in this paper. Originality/value – No other research or study has been proposed in current literature relating specifically to the use of portraits (looking at and creating) to help individuals with ASD.

Effect of appeal orientation in sponsored ad forwarding on a microblog platform

2020 ◽  
Vol 30 (6) ◽  
pp. 1835-1856
Author(s):  
Chenyan Gu ◽  
Yunjie Calvin Xu ◽  
Minghui Yao
Keyword(s):  
Design Methodology ◽  
Control Group ◽  
Main Experiment ◽  
Random Assignment ◽  
Message Content ◽  
Marketing Practice ◽  
Content Type ◽  
New Type ◽  
The Right ◽  
Content Design

PurposeThis study identifies a new type of advertising, sponsored ad forwarding, in microblog contexts. It tests the effectiveness of designs of a message with an ad with regard to receivers who are purely online friends or offline friends.Design/methodology/approachIn the main experiment, a three-by-two experimental design was employed. By random assignment, message senders forwarded an ad with either an other-oriented or a self-oriented message to a group of offline friends or purely online friends. In the control group, there was no message accompanying the ad. The data of 218 effective sender-receiver dyads were collected and compared.FindingsThe results show that a message with an other-oriented appeal is more effective than one with a self-oriented appeal for dyads with an offline relationship, and a message with a self-oriented appeal is more effective than one with an other-oriented appeal for dyads with a purely online relationship. Overall, the use of appeals significantly boosts ad effectiveness.Originality/valueThis study identifies a new type of marketing practice in social media, namely sponsored ad forwarding. It also proposes appeal orientation as a novel type of message content design. It shows how to apply the right appeal orientation to the right receiver groups, that is, offline or purely online friends.

Emerging social and business trends associated with the Covid-19 pandemic

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamid Yeganeh
Keyword(s):  
Design Methodology ◽  
Multidisciplinary Approach ◽  
Synthesis Method ◽  
Comprehensive Investigation ◽  
Content Type ◽  
New Era ◽  
The Past ◽  
New Type ◽  
High Connectivity ◽  
Work And Organizations

Purpose This paper aims to identify, classify and study emerging social and business trends associated with the outbreak of the Covid-19 pandemic. Design/methodology/approach By adopting the meta-synthesis method, the study scrutinizes, synthesizes and interprets the findings from a pool of publications. This approach results in identifying 53 key ideas that are classified under nine dominant trends. Findings The study identifies and examines nine major trends caused and intensified by the Covid-19 pandemic, i.e. the rise of authoritarianism, the new era of corporate welfare, deep imbalances in public finances, exacerbated inequalities, higher risks of poverty and famine, the dominance of giant corporations, the increasing influence of big tech, the accelerated innovation and the fluidity of work and organizations. The paper suggests that these trends are the continuation of the past three decades’ transformations, are contributing to the rising concentration of power and wealth and are leading to a new type of globalization marked by high connectivity and low tangibility. Originality/value The originality of this paper resides in adopting a multidisciplinary approach to analyzing various social and business dimensions of a complex phenomenon. While the study should not be viewed as a comprehensive investigation, it offers a groundwork for further research on Covid-19.

A longitudinal study of the efficacy of lean learning experienced through a simulated working environment (SWE)

2017 ◽  
Vol 66 (5) ◽  
pp. 651-661 ◽  
Author(s):  
Karl R. van der Merwe
Keyword(s):  
Experiential Learning ◽  
Learning Process ◽  
Design Methodology ◽  
Assembly Line ◽  
Learning Experience ◽  
Initial Study ◽  
Working Environment ◽  
Content Type ◽  
Student Views ◽  
New Type

Purpose The purpose of this paper is to determine the efficacy of lean learning as experienced and demonstrated by a group of students who were exposed to a purpose built simulated working environment (SWE). The study expands on previous research aimed at establishing the student views of the new type of training by including the perceptions of the industry mentors. Design/methodology/approach An SWE was developed to allow students to experience an assembly line environment and practice lean tools. The students’ perceptions of the learning process and the perceptions of their industry mentors were then measured to gauge the success of the programme. Findings Groups of students indicated that they believed their grasp of the basic lean concepts had been significantly enhanced through exposure to the SWE teaching exercises. The outcome of this initial study was endorsed by the findings of the second study that measured the perceptions of their industry mentors after a six-month experiential learning period. Research limitations/implications The research covered in this paper reflects only the findings of these two groups as they progressed from the SWE-type training to industry-based experiential learning. It is acknowledged that expanded research would be beneficial to not only verify initial findings but also to refine the lean learning experienced in the simulated work environment. Originality/value The paper describes a lean learning process that is more effective than current processes and could therefore be universally utilised to enhance the lean learning experience in higher education.

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