Assessment of Thermally-Actuated Pumping in an Open-Ended Channel With Multi-Scale Surface Asymmetry

2021 ◽  
Author(s):  
Ramuel Safarkoolan ◽  
Emre Ozen ◽  
Vinod Narayanan ◽  
Sushil Bhavnani
Keyword(s):  
Multi Scale ◽  
Thermally Actuated ◽  
Scale Surface

Assessment of Thermally-Actuated Pumping in an Open-Ended Channel With Multi-Scale Surface Asymmetry

2021 ◽  
Author(s):  
Ramuel Safarkoolan ◽  
Emre Ozen ◽  
Vinod Narayanan ◽  
Sushil Bhavnani
Keyword(s):  
Multi Scale ◽  
Thermally Actuated ◽  
Scale Surface

Multi-Scale Surface Characterization and Control Based High Density Measurements

2014 ◽  
Author(s):  
Xin Weng ◽  
Xiaoning Jin ◽  
Jun Ni
Keyword(s):  
Surface Quality ◽  
Process Monitoring ◽  
Surface Characterization ◽  
Quality Evaluation ◽  
Surface Shape ◽  
Machined Surface ◽  
Multi Scale ◽  
And Control ◽  
Scale Surface ◽  
Machined Surfaces

It is widely observed that today’s engineering products demand increasingly strict tolerances. The shape of a machined surface plays a critical role to the desired functionality of a product. Even a small error can be the difference between a successful product launch and a major delay. Thus, it is important to develop measurement tools to ensure the quality and accuracy of products’ machined surfaces. The key to assessing the quality is robust measurement and inspection techniques combined with advanced analysis. However, conventional Geometrical Dimensioning and Tolerancing (GD&T) such as flatness falls short of characterizing the surface shape. With the advancements in metrology methodology utilizing digital holographic interferometry, large amount of surface data can be captured at high resolution and accuracy without changing platform or technique. This captured High Definition Data (HDD) enables the mining of more valuable information from machined surfaces that most current industry practice cannot achieve in a timely manner. Such new metrology system opens the torrent of observable events at plant floor and increases the transparency of machining processes. This presents great opportunities to characterize machined surface into a new level of details, which can be applied in production quality evaluation and process condition monitoring and control. This research work proposes a framework of a multi-scale surface characterization for surface quality evaluation and process monitoring. Case studies are presented to show how proposed metrics could be applied in surface quality evaluation and process monitoring.

Lubricant migration on stainless steel induced by bio-inspired multi-scale surface patterns

2018 ◽  
Vol 150 ◽  
pp. 55-63 ◽  
Author(s):  
Philipp G. Grützmacher ◽  
Andreas Rosenkranz ◽  
Adam Szurdak ◽  
Carsten Gachot ◽  
Gerhard Hirt ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Multi Scale ◽  
Surface Patterns ◽  
Lubricant Migration ◽  
Scale Surface

Multi-scale surface patterning – an approach to control friction and lubricant migration in lubricated systems

2019 ◽  
Vol 71 (8) ◽  
pp. 1007-1016 ◽  
Author(s):  
Philipp G. Grützmacher ◽  
Andreas Rosenkranz ◽  
Adam Szurdak ◽  
Markus Grüber ◽  
Carsten Gachot ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Journal Bearing ◽  
Friction Reduction ◽  
Patterned Surfaces ◽  
Test Rig ◽  
Content Type ◽  
Multi Scale ◽  
Surface Patterns ◽  
Lubricant Migration ◽  
Scale Surface

Purpose The paper aims to investigate the possibilities to control friction in lubricated systems by surface patterning, making use of a multi-scale approach. Surface patterns inside the tribological contact zone tend to directly reduce friction, whereas surface patterns located in the close proximity of the contact area can improve the tribological performance by avoiding lubricant starvation and migration. Finally, optimized surface patterns were identified by preliminary laboratory tests and transferred to a journal bearing, thus testing them under more realistic conditions. Design/methodology/approach Surface patterns on a large scale (depth > 10 µm) were fabricated by micro- and roller-coining, whereas surface patterns on a small scale (depth < 2 µm) were produced by direct laser interference patterning. The combination of both techniques resulted in multi-scale surface patterns. Tribologically beneficial surface patterns (verified in ball-on-disk laboratory tests) were transferred onto a journal bearing’s shaft and tested on a special test-rig. To characterize the lubricant spreading behavior, a new test-rig was designed, which allowed for the study of the lubricant’s motion on patterned surfaces under the influence of a precisely controlled temperature gradient. Findings All tested patterns accounted for a pronounced friction reduction and/or an increase in oil film lifetime. The results from the preliminary laboratory tests matched well, with results from the journal bearing test-rig, both tests showing a maximum friction reduction by a factor of 3-4. Numerical investigations, as well as experiments, have shown the possibility to actively guide lubricant over patterned surfaces. Smaller periodicities, as well as greater structural depths and widths, led to a more pronounced anisotropic spreading and/or greater spreading velocities. Multi-scale surfaces demonstrated the strongest effects regarding the lubricant’s spreading behavior. Originality/value Friction, as well as lubricant migration, can be successfully controlled by using micro-coined, laser-patterned and/or multi-scale surfaces. To the best of the authors’ knowledge, the study demonstrates for the first time the unique possibility to transfer results obtained in laboratory tests to a real machine component.

Spark plasma sintering for multi-scale surface engineering of materials

JOM ◽  
2010 ◽  
Vol 62 (6) ◽  
pp. 65-71 ◽  
Author(s):  
Mrinalini Mulukutla ◽  
Ashish Singh ◽  
Sandip P. Harimkar
Keyword(s):  
Spark Plasma Sintering ◽  
Surface Engineering ◽  
Multi Scale ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scale Surface

scholarly journals Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

Lubricants ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 95 ◽  
Author(s):  
Philipp G. Grützmacher ◽  
Francisco J. Profito ◽  
Andreas Rosenkranz
Keyword(s):  
Friction And Wear ◽  
Current Knowledge ◽  
Surface Texturing ◽  
Research Direction ◽  
Point Of View ◽  
Surface Textures ◽  
Multi Scale ◽  
Advantages And Disadvantages ◽  
Single Scale ◽  
Scale Surface

Surface texturing has been frequently used for tribological purposes in the last three decades due to its great potential to reduce friction and wear. Although biological systems advocate the use of hierarchical, multi-scale surface textures, most of the published experimental and numerical works have mainly addressed effects induced by single-scale surface textures. Therefore, it can be assumed that the potential of multi-scale surface texturing to further optimize friction and wear is underexplored. The aim of this review article is to shed some light on the current knowledge in the field of multi-scale surface textures applied to tribological systems from an experimental and numerical point of view. Initially, fabrication techniques with their respective advantages and disadvantages regarding the ability to create multi-scale surface textures are summarized. Afterwards, the existing state-of-the-art regarding experimental work performed to explore the potential, as well as the underlying effects of multi-scale textures under dry and lubricated conditions, is presented. Subsequently, numerical approaches to predict the behavior of multi-scale surface texturing under lubricated conditions are elucidated. Finally, the existing knowledge and hypotheses about the underlying driven mechanisms responsible for the improved tribological performance of multi-scale textures are summarized, and future trends in this research direction are emphasized.

scholarly journals Multi-scale surface topography to minimize adherence and viability of nosocomial drug-resistant bacteria

2018 ◽  
Vol 140 ◽  
pp. 332-344 ◽  
Author(s):  
Jafar Hasan ◽  
Shubham Jain ◽  
Rinsha Padmarajan ◽  
Swathi Purighalla ◽  
Vasan K. Sambandamurthy ◽  
...  
Keyword(s):  
Surface Topography ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Multi Scale ◽  
Drug Resistant Bacteria ◽  
Scale Surface
Sign in / Sign up

Export Citation Format

Share Document