Ferrofluid lubrication for ball bearings to avoid starvation

2020 ◽  
Vol 72 (10) ◽  
pp. 1227-1231
Author(s):  
Mancheng Xu ◽  
Guanghu Jin ◽  
Qingwen Dai ◽  
Wei Huang ◽  
Xiaolei Wang
Keyword(s):  
Magnetic Field ◽  
Service Life ◽  
Peer Review ◽  
Design Methodology ◽  
Ball Bearing ◽  
Magnetic Circuit ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
Content Type ◽  
Circuit Structure

Purpose This paper aims to prevent oil starvation and improve the service life of the rolling bearings. Design/methodology/approach A thrust ball bearing with magnetic circuit structure is proposed for ferrofluid lubrication. With the aid of magnetic field, ferrofluid can be maintained in the contact area of rolling bodies to delay lubricant loss. Experiments are performed to ensure the validity of the designed bearing. Findings Compared with conventional lubricant, service life of the ferrofluid lubricated bearing can be prolonged under magnetic field. In addition, with a proper magnetic field distribution, lubricant starvation may be limited under the conditions of present experiments. Originality/value This work provides a method to control the starved lubrication of rolling bearings with restricted lubricant supply. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0132/

Wisconsin Assistive Technology Initiative framework for supporting assistive technology decision-making in Singapore schools: perspectives of in-service educators

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Meng Ee Wong ◽  
YingMin Lee
Keyword(s):  
Decision Making ◽  
Assistive Technology ◽  
Peer Review ◽  
Design Methodology ◽  
Resource Constraints ◽  
Written Feedback ◽  
Technology Initiative ◽  
Content Type ◽  
Trial Experience ◽  
Practical Implications

PurposeThis study explored in-service educators' experience of using the Wisconsin Assistive Technology Initiative (WATI) for assistive technology (AT) decision-making within Singapore schools.Design/methodology/approachThe study adopted a qualitative design. Eight educators across both mainstream and special education schools were introduced to the WATI framework which they subsequently employed as a trial experience for a student under their care. Written feedback gathered from participants was analysed to identify common issues and themes regarding the use of the WATI framework for AT decision-making.FindingsThe comprehensive consideration of a broad scope of different factors, provision of a structured process for AT decision-making, as well as a common language for use by different stakeholders emerged as key benefits of implementing the WATI. Challenges encountered include administrative struggles in gathering different stakeholders together, time and resource constraints and difficulties in loaning AT devices for trial use.Practical implicationsBased on educators' feedback, recommendations to facilitate the adoption of the WATI for AT decision-making within Singapore schools are discussed and considered. This study also highlights the need for greater AT instruction within both preservice and in-service teacher preparation programmes in Singapore.Originality/valueSchools in Singapore currently rarely adopt any frameworks in place to guide educators through a systematic process of AT consideration. It is anticipated that this study will spearhead and drive the adoption of systematic frameworks such as the WATI for better AT decision-making within Singapore schools.Peer reviewThe peer review history for this article is available at: https://publons.com/publon 10.1108/JET-03-2021-0015

Oil Pumping in High Speed and High Loaded Ball Bearings

2004 ◽  
Author(s):  
Michael Flouros
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Research Programme ◽  
Aircraft Engine ◽  
Ball Bearings ◽  
European Research ◽  
Rolling Bearings ◽  
Engine Design ◽  
Oil Flow ◽  
Total Oil

Trends in aircraft engine design cause increased mechanical stress requirements for rolling bearings. Consequently high amounts of heat are rejected which results in high oil scavenge temperatures. The direction of oil flow in the bearing can considerably affect the heat transported by the oil. An RB199 turbofan bearing and its associated chamber were modified to carry out the survey. The test bearing was a 124mm PCD ball bearing. The bearing has a split inner-ring employing under-race lubrication by two individual jets. The total oil flow could be devided to any ratio through the jets. This had an impact on the oil scavenge temperatures and the scavenge flows on both sides of the bearing. Significant reduction in the ‘heat to oil’ was achieved when oil was fed at certain proportions (ratio). This work is part of the European Research programme Brite Euram ATOS (Advanced Transmission and Oil Systems).

What makes peer review helpfulness evaluation in online review communities? An empirical research based on persuasion effect

2020 ◽  
Vol 44 (6) ◽  
pp. 1267-1286
Author(s):  
Yani Wang ◽  
Jun Wang ◽  
Tang Yao ◽  
Ming Li
Keyword(s):  
Peer Review ◽  
Design Methodology ◽  
Evaluation Research ◽  
Econometric Models ◽  
Online Review ◽  
Content Type ◽  
Review Helpfulness ◽  
New Perspective ◽  
The Relationship

PurposeThe purpose of this paper is to examine the mechanism of how peer review helpfulness evaluation in online review communities is established, drawing upon the internalization and identification routes of persuasion effect.Design/methodology/approachBased on book reviews selected from Douban.com (a prestigious review community in China), this study used econometric models to investigate the effects of both reviews and reviewers’ characteristics on peer review helpfulness evaluation in review communities.FindingsReview internalization is more persuasive than reviewers’ identification in peer evaluations, in terms of both short and long reviews. Reviews with extreme negative ratings tend to obtain higher level of helpfulness evaluation than those with positive or moderate ratings. The influence of reviewers’ characteristics is a significant cue in helping consumers to establish the trust perception in the context of short reviews, while its function diminishes in the context of long reviews, thus suggesting the importance of reviewers’ identification for short reviews in review communities.Social implicationsThe findings will enhance current understanding of peer review review helpfulness evaluation in online review communities and help practitioners administrate community reviews intelligently, help members write better reviews and customers in their product browsing experience.Originality/valueFirst, this study enriches review evaluation research in review communities by demonstrating the importance of internalization and identification lens of persuasion effect when explaining review helpfulness; second, this study helps to confirm the existing findings that reviews with extreme negative ratings are more helpful than those with moderate or positive ratings in review communities; third, this study proposes a new perspective pertaining to the relationship between reviewers’ identification and helpfulness evaluation.

Performance studies of textured race ball bearing

2019 ◽  
Vol 71 (9) ◽  
pp. 1116-1123 ◽  
Author(s):  
Vivek Bhardwaj ◽  
R.K. Pandey ◽  
V.K. Agarwal
Keyword(s):  
Ball Bearing ◽  
Dynamic Performance ◽  
Critical Role ◽  
Operating Conditions ◽  
Frictional Torque ◽  
Bulk Temperature ◽  
Back Side ◽  
Ball Bearings ◽  
Content Type ◽  
Long Duration

Purpose The purpose of this paper is to develop an energy-efficient and dynamically improved thrust ball bearing using textured race. A texture has been used on the stationary race of the test bearing to conduct the long-duration experiment for exploring its tribological and vibrational behaviours under starved lubricating condition using micro size MoS2 blended grease. The performance behaviours of the textured race bearing have been compared with conventional bearing (i.e. having both races without textures) under the identical operating conditions for demonstrating the advantages of textured race. Design/methodology/approach Texture was created on stationary race of the test ball bearing (51308) using nano-second pulsed Nd: YAG laser. Performance parameters (frictional torque, temperature rise and vibrations) of textured ball bearings were measured under severe starved lubricating conditions for understanding the critical role of texture in the long duration of the test. S-type load cell and miniature accelerometer were used for measuring the frictional torque and vibration, respectively. Bulk temperature at stationary races (at the back side) of test bearings was measured in operating conditions using a non-contact infrared thermometer. Findings Significant reduction in frictional torque and decrease in amplitude of vibration with textured ball bearing were found even under the severe starved lubricating condition in comparison to conventional bearing. Originality/value There is dearth of research pertaining to the performance behaviours of ball bearings using textures on the races. Therefore, an attempt has been made in this study to explore the tribo-dynamic performance behaviours of a thrust ball bearing using a texture on its stationary race under severe starved lubricating condition for the longer duration of the test.

A theoretical investigation for mixed convection impact in non-Newtonian nanofluid stratified flow subjected to magnetic field

2019 ◽  
Vol 29 (8) ◽  
pp. 2948-2963 ◽  
Author(s):  
Muhammad Waqas ◽  
Muhammad Mudassar Gulzar ◽  
Zeeshan Asghar ◽  
Z. Ali ◽  
Waqar Azeem Khan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Thermal Stratification ◽  
Design Methodology ◽  
Thermal Field ◽  
Second Grade ◽  
Second Grade Fluid ◽  
Nanofluid Flow ◽  
Content Type ◽  
Grade Fluid

Purpose The purpose of this study is to elaborate mixed convection impact in stratified nanofluid flow by convectively heated moving surface. Rheological relations of second-grade fluid are used for formulation. Magnetic field, heat absorption/generation and convective conditions are considered for modeling. Design/methodology/approach Convergent solutions are achieved using homotopy procedure. Findings The authors found opposing behavior for radiation and thermal stratification variables against thermal field. Originality/value No such analysis has yet been reported.

Kinematic investigation and fatigue life analysis of angular contact ball bearing in wide speed range based on raceway friction

2020 ◽  
Vol 72 (7) ◽  
pp. 845-850
Author(s):  
Yue Liu
Keyword(s):  
Fatigue Life ◽  
Peer Review ◽  
High Speed ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Angular Contact Ball Bearing ◽  
Content Type ◽  
Speed Range ◽  
Uniform Model ◽  
Wide Speed Range

Purpose The purpose of this paper is to clarify the relationship between fatigue life and kinematics of angular contact ball bearing. It proposes a new modeling method of spin to roll ratio based on raceway friction, which is more accurate than the traditional raceway control theory. Design/methodology/approach The uniform model of spin to roll ratio based on raceway friction in a wide speed range is proposed using quasi-statics method, which considers centrifugal force, gyroscopic moment, friction force of raceway and other influencing factors. The accuracy is considerably improved compared with the static model without increasing too much computation. Findings A uniform model for spin to roll ratio of angular contact ball bearing based on raceway friction is established, and quite different relationships between fatigue life and speed under two operating conditions are found. Research limitations/implications The conclusion of this paper is based on the bearing basic fatigue life calculation theory provided by ISO/TS 16281; however, the accuracy of theory needs to be further verified. Practical implications This paper provides guidance for applying angular contact ball bearing, especially at a high speed. Originality/value This paper reveals the changing trend of fatigue life of angular contact ball bearing with the speed under different loads. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0030

Impact of supply voltage variations on external magnetic field emitted by induction machines

2017 ◽  
Vol 36 (3) ◽  
pp. 692-701
Author(s):  
Mohamed Omar Younsi ◽  
Olivier Ninet ◽  
Fabrice Morganti ◽  
Jean-Philippe Lecointe ◽  
Farid Zidat ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Circuit ◽  
Supply Voltage ◽  
Induction Machines ◽  
Tangential Component ◽  
Content Type ◽  
Internal Fault ◽  
Torque Estimation ◽  
Numerical Finite Element

Purpose This paper aims to study the influence of supply voltage variations on the external magnetic field emitted by grid-powered induction machines (IMs). Design/methodology/approach Two models are developed in the paper to analyse, for different supply voltage values, the influence of the variations of the magnetizing voltage for which there is a link with the tangential component of the external flux. The first is an analytical model based on the IM single-phase-equivalent circuit with variable magnetizing reactance to take into account the saturation of the magnetic circuit. The second is a numerical finite element simulation to model the same phenomenon. Results of both models are analysed with experimental measures of the external flux. Findings The study shows that the amplitude of the external field strongly depends on supply voltage values. Research limitations/implications The investigation is mainly focused on the tangential component of the external magnetic field which is of high importance concerning the applicability of non-invasive methods of diagnosis, as electromagnetic torque estimation developed by the authors or internal fault determination. Originality/value The originality of the paper concerns the characterization of the external flux with the supply voltage for IMs. It is shown that the magnetic circuit radiates external flux differently with the load and with the supply voltage.

Information activities as serious leisure within the fanfiction community

2017 ◽  
Vol 73 (5) ◽  
pp. 843-857 ◽  
Author(s):  
Heather Hill ◽  
Jen J.L. Pecoskie
Keyword(s):  
Peer Review ◽  
Design Methodology ◽  
Information Science ◽  
Library And Information Science ◽  
Serious Leisure ◽  
Significant Information ◽  
Cultural Products ◽  
Content Type ◽  
Digital Heritage ◽  
Practical Implications

Purpose Fanfiction communities are actively engaged in creating cultural products. These large online communities have created and developed conventions that guide their solutions to gathering and presenting their work. The purpose of this paper is to investigate those conventions looking for evidence of information-related pursuits as serious leisure (SL) (Stebbins, 2007). Design/methodology/approach A diverse collection of fanfiction publishing platforms, blogs, and associated websites were subject to a qualitative inductive analysis (Lincoln and Guba, 1985). Platforms included both generalist sites like Archive of Our Own and more focused sites such as Teen Wolf Fic Finder. Findings Findings show significant information-related activities around collecting, wayfinding, and organizing. Collecting centers on platform policies focused on scope. Wayfinding relates to peer review as well as various reference-like work including reader’s advisory, reference questioning, and the creation of pathfinders. Organizing looks to the unique organizational schema created and used by the fanfiction communities. Research limitations/implications The authors explore implications of these activities in reference to the fanfiction community and the library and information science (LIS) discipline. The fanfiction community is shifting out of an ephemeral existence and into one of a more permanent digital heritage. Fanfiction is an SL pursuit that also has much to offer for consideration to the LIS discipline. Practical implications With respect to the wayfinding and organizing conventions of fanfiction communities, these activities provide librarianship with the opportunity to consider traditional activities in new ways. Originality/value Fanfiction is a little studied phenomenon in SL and in LIS. This research provides connections to both areas.

A study for steady nanofluid flow between parallel plates

2017 ◽  
Vol 34 (8) ◽  
pp. 2514-2527 ◽  
Author(s):  
Syed Tauseef Mohyud-din ◽  
Muhammad Asad Iqbal ◽  
Muhammad Shakeel
Keyword(s):  
Magnetic Field ◽  
Differential Equations ◽  
Uniform Magnetic Field ◽  
Design Methodology ◽  
Magnetic Parameter ◽  
Parallel Plates ◽  
Nanofluid Flow ◽  
Content Type ◽  
Viscosity Parameter ◽  
Variation Of Parameters

Purpose In this paper, the authors study the behavior of heat and mass transfer between parallel plates of a steady nanofluid flow in the presence of a uniform magnetic field. In the model of nanofluids, the essential effect of thermophoresis and Brownian motion has been encompassed. Design/methodology/approach The variation of parameters method has been exploited to solve the differential equations of nanofluid model. The legitimacy of the variation of parameters method has been corroborated by a comparison of foregoing works by many authors on viscous fluid. Findings An analysis of the model is performed for different parameters, namely, viscosity parameter, Brownian parameter, thermophoretic parameter and magnetic parameter. Originality/value The variation of parameters method proves to be very effective in solving nonlinear system of ordinary differential equations which frequently arise in fluid mechanics.

Significance of heat generation/absorption in magnetohydrodynamic flow by an unsteady stretching curved surface

2020 ◽  
Vol 17 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Taseer Muhammad
Keyword(s):  
Magnetic Field ◽  
Nonlinear System ◽  
Prandtl Number ◽  
Heat Generation ◽  
Design Methodology ◽  
Shooting Method ◽  
Time Dependent ◽  
Curved Surface ◽  
Heat Absorption ◽  
Content Type

PurposeThe purpose of this article is to analyze the magnetohydrodynamic viscous liquid flow with heat absorption/generation. Flow is induced by an unsteady stretching curved surface. A time-dependent magnetic field is utilized.Design/methodology/approachThe resulting nonlinear system is solved through shooting method.FindingsAn increment in the values of curvature A and unsteadiness parameters correspond to higher velocity, temperature and concentration fields. There is a reduction in the temperature and related layer via Prandtl number. Skin friction is increasing factor of magnetic number. Local Nusselt and Sherwood numbers are lower for greater magnetic number.Originality/valueTo the best of author's knowledge, no such consideration has been given in the literature yet.

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