Review of Friction and Surface Properties of Snakeskin

2018 ◽  
pp. 276-315
Author(s):  
Hisham A. Abdel-Aal
Keyword(s):  
Surface Properties ◽  
Surface Engineering ◽  
Surface Geometry ◽  
Design Features ◽  
Surface Design ◽  
Technical Problems ◽  
Natural Systems ◽  
Biological World ◽  
Diverse Habitat

Locomotion is an essential activity in the biological world. Friction affects the energy invested in motion. Natural systems tend to conserve energy. As such, it is necessary to mitigate the effects of friction. There are many intriguing examples of creatures where dynamics of motion and surface geometry (macro and micro) combine to optimize the tribological profile. One example is that of snakes. In snakes, texturing geometries and topologies specifically contribute to frictional mitigation in a variety of situations. Snakes are found everywhere on earth. Their diverse habitat presents a broad range of tribological environments. This requires customized surface design features that potentially can inspire deterministic solutions for many technical problems. Therefore, they have attracted attention lately. Many, from surface engineering to robotics, have started to study their tribological response and frictional characteristics. This chapter attempts to review the major findings about the tribology of the legless reptiles obtained through the last two decades.

Perceived Glossiness: Beyond Surface Properties

2019 ◽  
Vol 2019 (1) ◽  
pp. 37-42
Author(s):  
Davit Gigilashvili ◽  
Jean-Baptiste Thomas ◽  
Marius Pedersen ◽  
Jon Yngve Hardeberg
Keyword(s):  
Surface Properties ◽  
Human Subjects ◽  
Surface Geometry ◽  
Surface Reflection ◽  
Different Color

Gloss is widely accepted as a surface- and illuminationbased property, both by definition and by means of metrology. However, mechanisms of gloss perception are yet to be fully understood. Potential cues generating gloss perception can be a product of phenomena other than surface reflection and can vary from person to person. While human observers are less likely to be capable of inverting optics, they might also fail predicting the origin of the cues. Therefore, we hypothesize that color and translucency could also impact perceived glossiness. In order to validate our hypothesis, we conducted series of psychophysical experiments asking observers to rank objects by their glossiness. The objects had the identical surface geometry and shape but different color and translucency. The experiments have demonstrated that people do not perceive objects with identical surface equally glossy. Human subjects are usually able to rank objects of identical surface by their glossiness. However, the strategy used for ranking varies across the groups of people.

An Area Preserving Transformation Algorithm for Press Forming Blank Development

1993 ◽  
Author(s):  
Nirmal K. Nair ◽  
James H. Oliver
Keyword(s):  
Time Complexity ◽  
Linear Time ◽  
Geometric Interpretation ◽  
Surface Geometry ◽  
Forming Process ◽  
Surface Design ◽  
Design Assessment ◽  
Press Forming ◽  
Blank Shape ◽  
Area Preserving

Abstract An efficient algorithm is presented to determine the blank shape necessary to manufacture a surface by press forming. The technique is independent of material properties and instead uses surface geometry and an area conservation constraint to generate a geometrically feasible blank shape. The algorithm is formulated as an approximate geometric interpretation of the reversal of the forming process. The primary applications for this technique are in preliminary surface design, assessment of manufacturability, and location of binder wrap. Since the algorithm exhibits linear time complexity, it is amenable to implementation as an interactive design aid. The algorithm is applied to two example surfaces and the results are discussed.

scholarly journals EXPERIMENTAL FACILITY FOR THE STUDY OF THE PROCESSES IN MIXING LOW-PRESSURE HEATERS OF K-1000-60/3000 TURBINES

2020 ◽  
Vol 2 (61) ◽  
pp. 42-50
Author(s):  
A. Smychok ◽  
◽  
V. Gerliga ◽  
V. Zaporozhan ◽  
M. Panchenko ◽  
...  
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Experimental Studies ◽  
Operating Experience ◽  
Low Pressure ◽  
Main Task ◽  
Experimental Facility ◽  
Design Features ◽  
Technical Problems ◽  
Hydraulic Processes

Nowadays, the development of nuclear energy is determined by solving the set of scientific and technical problems that provides reliable, safe and sustainable work of the operated and designed NPPs. At the same time different accident conditions and likelihood (probability) of variant equipment operating failures are analyzed. Obtained operating experience of the mixing low-pressure heaters (LPH) at thermal power plants (TPP) and NPPs shows that pulsations occur in some operation regimes of LPH turbine which lead to inner element destructions of LPH and pipeline malfunctions. These circumstances negatively affect operation of equipment that locates after LPH in condensate-supply tract. Consequently, unit capacity factor and economic indicators descend since troubleshooting for LPH mechanisms require some time and material resources. This work presents the experimental facility design and description of main design features of the facility components. The stand was designed to study the processes that lead to the vibration appearance in mixing LPH in condensate-supply tract of K-1000-60/3000 turbines. The main task of scale modeling is the need to observe equivalent conditions of the thermal-hydraulic processes behavior in the model in relation to full-scale equipment. To solve this problem using ANSYS code a preliminary simulation of hydraulic processes occurring in the experimental facility was performed. This allowed to determine in advance certain design features in the design of given facility. The results of experimental studies of the developed facility should allow to develop measures for reduction or complete elimination of vibrations in mixing LPH, as well as to validate computer programs for design analysis of stationary and non-stationary thermal-hydraulic processes in the specified equipment and designed measures testing.

A Review on Surface Engineering of Ti6Al4V Titanium Alloy Using Gas and Laser Nitriding Techniques

2015 ◽  
Vol 766-767 ◽  
pp. 618-625 ◽  
Author(s):  
J.R Deepak
Keyword(s):  
Titanium Alloy ◽  
Surface Properties ◽  
Surface Engineering ◽  
Surface Hardness ◽  
Aircraft Engine ◽  
Ti6al4v Alloy ◽  
Surface Stability ◽  
Laser Nitriding ◽  
Gas Nitriding ◽  
Grade 5

Nitriding is the most common surface engineering technique that is being used in Titanium alloys for improving their surface properties, viz hardness, wear resistance, etc. Ti6Al4V (Grade 5) Titanium Alloy is a super alloy that exhibits excellent mechanical strength; it is highly resistance to creep at very high temperatures which maintains good surface stability. It is resistant to corrosion and oxidation. The main objective of this review paper is to study the recent research works carried on Nitriding of Ti6Al4V alloy by using, viz gas Nitriding and laser Nitriding. This process is used in the surface hardening of machine parts such as aircraft engine parts, crank pins, valve seats, gears, bush, aero engine cylinders, aero crank shafts. Gas Nitriding is a diffusional technique in which the nitrogen atoms are diffused into the surface of the metal to obtain hard surface. By Laser Nitriding is a diffusional technique by which the surface properties of the titanium alloy is enhanced. Laser nitriding process comprises of various stages, viz, transport of heat, melting effect, diffusion and convection effect. By Nitriding technique the surface hardness of super alloys like Titanium Alloy Ti6Al4V Grade 5 can be increased by increasing the hardness on the surface there by its scope of application is widened. In this paper a literature survey is carried out and the recent research works on surface engineering of Ti6Al4V alloy using gas and laser Nitriding technique is summarized.

Surface Engineering by HIP

1991 ◽  
Vol 251 ◽  
Author(s):  
David J Stephenson
Keyword(s):  
Surface Properties ◽  
Surface Engineering ◽  
Surface Defects ◽  
Hot Isostatic Pressing ◽  
Isostatic Pressing ◽  
Modify Surface

ABSTRACTMethods for surface treating and coating components by hot isostatic pressing are presented. It is shown that HIP'ing can improve the properties of conventional coatings and also be used to produce coatings that would be difficult to deposit by other techniques. The concept of using a combined coating and HIP treatment to modify surface properties by, for example, removing surface defects in metals and ceramics, is also discussed.

scholarly journals Femtosecond Laser Micro-/Nano-Texturing of Stainless Steels for Surface Property Control

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 512 ◽  
Author(s):  
Aizawa ◽  
Inohara ◽  
Wasa
Keyword(s):  
Contact Angle ◽  
Fractal Dimension ◽  
Femtosecond Laser ◽  
Surface Properties ◽  
Stainless Steels ◽  
Surface Property ◽  
Textured Surface ◽  
Surface Geometry ◽  
Static Contact ◽  
Property Control

Surface geometry has had an influence on the surface property, in addition to the intrinsic surface energy, of materials. Many physical surface modification methods had been proposed to control the solid surface geometry for modification of surface properties. Recently, short-pulse lasers were utilized to perform nano-texturing onto metallic and polymer substrates for the improvement of surface properties. Most of the papers reported that the hydrophilic metallic surface was modified to have a higher contact angle than 120–150°. Little studies explained the relationship between surface geometry and surface properties. In the present study, the laser micro-/nano-texturing was developed to describe this surface-geometric effect on the static contact angles for pure water. Micropatterns with multi spatial frequencies are designed and synthesized into a microtexture. This tailored microtexture was utilized to prepare for computer aided machining (CAM) data to control the femtosecond laser beams. The nano-length ripples by laser induced periodic surface structuring (LIPSS) supposed onto this microtexture to form the micro-/nano-texture on the AISI304 substrate surface. Computational geometry was employed to describe this geometric profile. The fractal dimension became nearly constant by 2.26 and insensitive to increase of static contact angle (θ) for θ > 150°. Under this defined self-similarity, the micro-/nano-textured surface state was controlled to be super-hydrophobic by increasing the ratio of the highest spatial frequency in microtextures to the lowest one. This controllability of surface property on the stainless steels was supported by tailoring the wavelength and pitch of microtextures. Exposure testing was also used to evaluate the engineering durability of this micro-/nano-textured surface. Little change of the measured fractal dimension during the testing proved that this physically modified AISI304 surface had sufficient stability for its long-term usage in air.

scholarly journals Thermally Sprayed Coatings: Novel Surface Engineering Strategy Towards Icephobic Solutions

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1434 ◽  
Author(s):  
Heli Koivuluoto ◽  
Enni Hartikainen ◽  
Henna Niemelä-Anttonen
Keyword(s):  
Surface Properties ◽  
Surface Engineering ◽  
Design Method ◽  
Composite Coatings ◽  
Thermal Spraying ◽  
Coating Materials ◽  
Sustainable Solutions ◽  
Thermally Sprayed Coatings ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Surface engineering promotes possibilities to develop sustainable solutions to icing challenges. Durable icephobic solutions are under high interest because the functionality of many surfaces can be limited both over time and in icing conditions. To solve this, one potential approach is to use thermally sprayed polymer or composite coatings with multifunctional properties as a novel surface design method. In thermal spraying, coating materials and structures can be tailored in order to achieve different surface properties, e.g., wetting performance, roughness and protection against several weathering and wearing conditions. These, in turn, are beneficial for excellent icephobic performance and surface durability. The icephobicity of several different surfaces are tested in our icing wind tunnel (IWiT). Here, mixed-glaze ice is accreted from supercooled water droplets and the ice adhesion is measured using a centrifugal adhesion tester (CAT). The present study focuses on the icephobicity of thermally sprayed coatings. In addition, surface-related properties are evaluated in order to illustrate the correlation between the icephobic performance and the surface properties of differently tailored thermally sprayed coatings as well as compared those to other coatings and surfaces.

Exploring the Use of Functional Models as a Foundation for Biomimetic Conceptual Design

2007 ◽  
Author(s):  
Andrea Tinsley ◽  
Prem A. Midha ◽  
Robert L. Nagel ◽  
Daniel A. McAdams ◽  
Robert B. Stone ◽  
...  
Keyword(s):  
Problem Solving ◽  
Case Studies ◽  
Natural World ◽  
Flapping Wing ◽  
Functional Modeling ◽  
Natural Systems ◽  
Functional Models ◽  
Biological World ◽  
Many Sources ◽  
High Level

The natural world provides numerous cases for analogy and inspiration. From simple cases such as hook and latch attachments to articulated-wing flying vehicles, nature provides many sources for ideas. Though biological systems provide a wealth of elegant and ingenious approaches to problem solving, there are challenges that prevent designers from leveraging the full insight of the biological world into the designed world. This paper describes how those challenges can be overcome through functional analogy. Through the creation of a function-based repository, designers can find biomimetic solutions by searching the function for which a solution is needed. A biomimetic function-based repository enables learning, practicing and researching designers to fully leverage the elegance and insight of the natural world. In this paper, we present the initial efforts of functional modeling natural systems and then transferring the principles of the natural system to an engineered system. Four case studies are presented in this paper. These case studies include a biological solution to a problem found in nature and engineered solutions corresponding to the high level functionality of the biological solution, i.e., a fly’s winged flight and a flapping wing aircraft. The case studies show that unique, creative engineered solutions can be generated through functional analogy with nature.

Surface Micro Patterning of Aluminium Reinforced Composite through Laser Peening

2017 ◽  
Vol 7 (4) ◽  
pp. 15-27 ◽  
Author(s):  
G. Ranjith Kumar ◽  
G. Rajyalakshmi ◽  
Vijaya Kumar Manupati
Keyword(s):  
Surface Properties ◽  
Surface Engineering ◽  
Weight Ratio ◽  
Hardened Layer ◽  
Laser Peening ◽  
Aluminium Composite ◽  
Micro Patterning ◽  
Reinforced Composite ◽  
Engineering Technique ◽  
The Impact

Aluminium Composites have universal engineering applications because of their higher strength to weight ratio, ductility, and formability. However, in diverse applications, mechanical properties are the prerequisite at closer surface regions. Such localized changes without impacting various surface treatment approaches can attempt the bulk phase. Laser peening is an advanced surface engineering technique, which has been successfully applied to improve the surface morphology of the material. In this work, the authors focus on improving the surface properties of Al7075 composite through laser peening technique. The hardened layer was evaluated using surface integrity with optical microscopy, EDS, SEM and analysis of microhardness. Process parameters and resulting microstructures of Aluminium composite are summarized, along with the impact of laser peening on surface properties. Research results indicated that laser peening shows a significant influence on the final condition of the surface layer of Aluminium composite.

scholarly journals Bioresorbable polymeric materials – current state of knowledge

Polimery ◽  
2021 ◽  
Vol 66 (1) ◽  
pp. 3-10
Author(s):  
Kamila Wiśniewska ◽  
Zbigniew Rybak ◽  
Marcin Wątrobiński ◽  
Marcin H. Struszczyk ◽  
Jarosław Filipiak ◽  
...  
Keyword(s):  
Surface Properties ◽  
Biodegradable Polymers ◽  
Tissue Regeneration ◽  
Bone Healing ◽  
Polymeric Materials ◽  
Surface Geometry ◽  
Current State ◽  
Variable Surface

Bioresorbable materials are used in medicine for fi xing, correcting or stabilizing bones in various anatomical areas, and the market for such materials is growing rapidly worldwide. The use of polymers for their production is associated with the ability to control their properties. They are prepared from bioresorbable materials with variable surface, geometry, porosity, as well as mechanical and surface properties. They support bone healing and are suitable for tissue regeneration due to their biodegradability and biocompatibility. We believe that materials from biodegradable polymers will play an increasingly important role in future medicine.

Sign in / Sign up

Export Citation Format

Share Document