Discrepancy in oil film distribution observed in ZEV reciprocating motion

Purpose This study aims to present the discrepancy in oil film distribution in reciprocating motion experimentally with zero entraining velocity (ZEV) on a conventional ball-disk test rig with oil lubrication. Design/methodology/approach Driven independently by two individual servomotors, a steel ball and a sapphire disc move at equal speed but in opposite directions in a triangle wave. The oil film images between the ball and the disc were recorded by a camera. After the experiments, the mid-section film thickness was evaluated by using a dichromatic interference intensity modulation approach. Findings The dimpled oil film in transient condition is shallower than that at steady state with the same load and velocities, and the transient dimple depth decreases with the decrease of time. The increase of the applied load offers a beneficial effect on lubrication. Boundary slippage happens in ZEV reciprocating motion. The slippage at the interface is related to the transient effect and applied load. Originality/value This study reveals the significant difference of the oil film variation in ZEV reciprocating motion, especially the complex boundary slippage at the interface of the oil and the sapphire disc. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0021

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A thermal EHL investigation for size effect of finite line contact on bush-pin hinge pairs in industrial chains

Industrial Lubrication and Tribology ◽

10.1108/ilt-10-2019-0448 ◽

2020 ◽

Vol 72 (5) ◽

pp. 695-701

Author(s):

Mingyu Zhang ◽

Jing Wang ◽

Peiran Yang ◽

Zhaohua Shang ◽

Yi Liu ◽

...

Keyword(s):

Film Thickness ◽

Peer Review ◽

Contact Zone ◽

Line Contact ◽

Equivalent Radius ◽

Content Type ◽

Oil Film ◽

Finite Line Contact ◽

Finite Line ◽

Thermal Ehl

Purpose This paper aims to study the influence of the dimension change of bush-pin on the pressure, oil film thickness, temperature rise and traction coefficient in contact zone by using a thermal elastohydrodynamic lubrication (EHL) model for finite line contact. Concretely, the effects of the equivalent curvature radius of the bush and the pin, and the length of the bush are investigated. Design/methodology/approach In this paper, the contact between the bush and pin is simplified as finite line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. A constitutive equation Ree–Eyring fluid is used in the calculations. Findings It is found that by selecting an optimal equivalent radius of curvature and prolonging the bush length can improve the lubrication state effectively. Originality/value Under specific working conditions, there exists an optimal equivalent radius to maximize the minimum oil film thickness in the contact zone. The increase of generatrix length will weaken the stress concentration effect in the rounded corner area at both ends of the bush, which can improve the wear resistance of chain. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0448.

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Application of smart electronic systems, firm characteristics and efficient energy consumption – a case of public universities in Uganda

International Journal of Social Economics ◽

10.1108/ijse-02-2019-0083 ◽

2020 ◽

Vol 47 (8) ◽

pp. 1023-1041

Author(s):

Juliet Isingoma-Wakaisuka ◽

Charles Kalvin Kikwanga Ibanda ◽

Ruqqaiya Naluwooza ◽

Christine Namaganda

Keyword(s):

Energy Consumption ◽

Technology Acceptance ◽

Peer Review ◽

Public Universities ◽

Electronic Systems ◽

Firm Characteristics ◽

Content Type ◽

Efficient Energy ◽

Significant Difference ◽

Acceptance Model

PurposeThe purpose of the study is to examine the relationship between the application of smart electronic systems, firm characteristics and efficient energy consumption: a case of public universities in Uganda.Design/methodology/approachThe study adopted both quantitative and qualitative approach as well as descriptive cross-sectional survey design tantamounting to an experimental-observation approach. A sample of four public academic universities were explored using primary data. A semi-structured questionnaire together with an evaluation form and a tested experimental kit (from one of the leading electronics centres in Uganda) was used to examine the consumption rates of different electronic appliances of less than 30 Amps. Further, a Pearson product moment correlation (r) analysis was also used to determine the direction of a relationship among the variables together with a linear relationship (regression) to predict a linear association of one or more variables. Recommendations were also given.FindingsSmart electronic systems make a significant determining factor to both firm characteristics (age, number of students, administrative staff and support staff) as well as efficient energy consumption. Nonetheless, there is no significant difference of efficient energy consumption as far as firm characteristics are concerned.Research limitations/implicationsResults support the contributions of the theory of technology and acceptance model by affirming that a number of factors influence the usefulness and ease of use of the smart electronic systems, which in turn influence energy consumption.Practical implicationsUniversities' management should endeavour to install smart electronic systems. But still, government should try to lower taxes on smart electronic systems and genuine agents should be named for easy and affordable access of the users, universities inclusive.Originality/valueThe study contributes towards a theoretical position by affirming the usefulness of technology acceptance model for efficient energy consumption in public universities.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-02-2019-0083

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An adjustable oil film thickness test rig for detecting lubrication characteristics of slipper/swash-pair in piston pumps

Industrial Lubrication and Tribology ◽

10.1108/ilt-05-2020-0166 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Haiji Wang ◽

Guanglin Shi

Keyword(s):

Film Thickness ◽

Peer Review ◽

Relative Error ◽

Mathematical Analysis ◽

Test Rig ◽

Content Type ◽

Oil Film ◽

Displacement Sensors ◽

Measuring Machine ◽

Lubrication Characteristics

Purpose The purpose of this paper is to propose an adjustable oil film thickness test rig for detecting lubrication characteristics of the slipper. The mathematical analysis of lubrication is introduced. Based on the results from the test rig, the results comparison from test rig and mathematical analysis is carried out. Design/methodology/approach This paper introduces a mechanism which can adjust the oil film thickness between the slipper and swash-plate. Feasibility is ensured, and the accuracy of test rig is guaranteed by the three-coordinate measuring machine. Three displacement sensors show the oil film thickness and its shape. The reacting force and torque resulting from oil film can be achieved by three S-type force sensors and a torque sensor, respectively. Findings The relative error of the reacting force is small. The relative error reduces and is acceptable when the deformation of retainer is taken into account. The thickness and tilt angle of oil film have less effect on the reacting force. However, they are significantly impact on torque. Originality/value The test rig proposed in this paper is able to adjust the oil film thickness, which is used to detecting the lubrication characteristics in pump design. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0166/

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