scholarly journals Quantify the Protein–Protein Interaction Effects on Adsorption Related Lubricating Behaviors of α-Amylase on a Glass Surface

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1658
Author(s):  
Nareshkumar Baskaran ◽  
You-Cheng Chang ◽  
Chia-Hua Chang ◽  
Shun-Kai Hung ◽  
Chuan-Tse Kao ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Ceramic Material ◽  
Glass Surface ◽  
Structural Changes ◽  
Tooth Enamel ◽  
Material Surface ◽  
Dental Ceramic ◽  
Adsorbed Protein ◽  
Wide Range

Dental ceramic material is one of the widely preferred restorative materials to mimic the natural tooth enamel surface. However, it has continuously been degraded because of low wear resistance during mastication in the oral cavity. The friction involved was reduced by introducing the lubricant saliva protein layers to improve the wear resistance of the dental materials. However, little is understood regarding how the protein–protein interactions (PPI) influence the adsorbed-state structures and lubricating behaviors of saliva proteins on the ceramic material surface. The objective of this study is to quantify the influences of PPI effects on the structural changes and corresponding oral lubrications of adsorbed α-amylase, one of the abundant proteins in the saliva, on the dental ceramic material with glass as a model surface. α-Amylase was first adsorbed to glass surface under varying protein solution concentrations to saturate the surface to vary the PPI effects over a wide range. The areal density of the adsorbed protein was measured as an indicator of the level of PPI effects within the layer, and these values were then correlated with the measurements of the adsorbed protein’s secondary structure and corresponding friction coefficient. The decreased friction coefficient value was an indicator of the lubricated surfaces with higher wear resistance. Our results indicate that PPI effects help stabilize the structure of α-amylase adsorbed on glass, and the correlation observed between the friction coefficient and the conformational state of adsorbed α-amylase was apparent. This study thus provides new molecular-level insights into how PPI influences the structure and lubricating behaviors of adsorbed protein, which is critical for the innovations of dental ceramic material designs with improved wear resistance.

scholarly journals Improvement of the method of evaluation of bitumen binder adhesion

2021 ◽  
Vol 2 (92) ◽  
pp. 57
Author(s):  
Yan Pyrig ◽  
Andrey Galkin ◽  
Victor Zolotaryov
Keyword(s):  
Glass Surface ◽  
Test Procedure ◽  
Research Work ◽  
National Standard ◽  
Test Time ◽  
Material Surface ◽  
Adhesion Properties ◽  
Temperature Regimes ◽  
Wide Range ◽  
Method Of Evaluation

Abstract. Problem. Adhesion can be used as one of the general indicators of interaction between bitumen binder and mineral aggregates in asphalt concrete. From this point of view adhesion of binder to mineral surface is one of the factors that directly provides strength and performance of asphalt road pavement. More than 20 years in Ukraine adhesion properties of bitumen evaluated with a ДСТУ Б В.2.7-81-98 standard method. This method is based on evaluation of bitumen adhesion to a glass slide, which is set as a standardized surface. Nowadays the list of the positions of ДСТУ Б В.2.7-81-98 is out of date that requires an improvement of adhesion evaluation method. Goal. This research work is aimed to improve the method of evaluation of bitumen binder adhesion to a glass and mineral material surface. Methodology. To reach the goal the following experimental researches are done: the analysis of different glass slides as a standardized surface, the improvement of the preparation method of glass surface for the test, the choice of the time-temperature regimes of the test. Results. It is found that glass sides for the microscope analysis can be set as a standardized glass surface for the test. Methods of glass surface preparation and a test procedure are improved. The regimes of samples heating and exposure before the test and a time-temperature regimes of the rest is changed in comparison with ДСТУ Б В.2.7-81-98. It was found that stripping of the glass surface in water with a time can be described as a polynomial function irrelevant to the test temperature. For each bitumen binder stripping tends to reach the specific constant level during a test time and stays practically unchanged at the further exposure. Originality. On the analysis of the obtained time-temperature relations for the test samples stripping it is set the test regimes and procedure that allows correct and precision evaluation of the adhesion level for a wide range of bitumen binders with additives. Practical value. The obtained experimental data is a base of developed project of national standard ДСТУ «Bitumen and bituminous binders. Determination of resistance to stripping on glass and aggregates surface».

Assessment of Tribological Properties of Low Friction Thin Layers Produced by Vacuum Methods

2019 ◽  
Vol 293 ◽  
pp. 125-140
Author(s):  
Agnieszka Paradecka ◽  
Krzysztof Lukaszkowicz ◽  
Jozef Sondor
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Chemical Analysis ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Structural Changes ◽  
Thin Layers ◽  
Low Friction ◽  
Topographic Analysis ◽  
Steel Substrates

Low friction thin layers are an excellent alternative for conventional coatings. They provide increased life of the elements, to which they were applied, due to enhancing the hardness or chemical and electrochemical resistance. They help to avoid the cracks, oxidation, as well as possible structural changes during the element's work. However, they primarily improve tribological properties by increasing wear resistance and reducing the friction. This also applies to components operating under variable conditions such as load, speed, temperature. The presented article analyzes the properties of various low-friction thin layers deposited by vacuum methods on the steel substrates. DLC, TiC, MoS2, CrCN thin layers were chosen, as they achieve the lowest possible coefficient of friction. In the framework of this work the measurements of adhesion of the investigated layers to the substrate as well as the friction coefficient, chemical analysis, microstructure and topographic analysis of the low-friction layers were carried out.

scholarly journals Correlation between Tribological Properties and the Quantified Structural Changes of Lysozyme on Poly (2-hydroxyethyl methacrylate) Contact Lens

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1639
Author(s):  
You-Cheng Chang ◽  
Chen-Ying Su ◽  
Chia-Hua Chang ◽  
Hsu-Wei Fang ◽  
Yang Wei
Keyword(s):  
Friction Coefficient ◽  
Protein Interactions ◽  
Contact Lens ◽  
Structural Changes ◽  
Hydroxyethyl Methacrylate ◽  
Tear Proteins ◽  
Adsorbed Protein ◽  
Adsorbed Proteins ◽  
Lens Material

The ocular discomfort is the leading cause of contact lens wear discontinuation. Although the tear proteins as a lubricant might improve contact lens adaptation, some in vitro studies suggested that the amount of adsorbed proteins could not simply explain the lubricating performance of adsorbed proteins. The purpose of this study was to quantify the structural changes and corresponding ocular lubricating properties of adsorbed protein on a conventional contact lens material, poly (2-hydroxyethyl methacrylate) (pHEMA). The adsorption behaviors of lysozyme on pHEMA were determined by the combined effects of protein–surface and protein–protein interactions. Lysozyme, the most abundant protein in tear, was first adsorbed onto the pHEMA surface under widely varying protein solution concentrations to saturate the surface, with the areal density of the adsorbed protein presenting different protein–protein effects within the layer. These values were correlated with the measured secondary structures, and corresponding friction coefficient of the adsorbed and protein covered lens surface, respectively. The decreased friction coefficient value was an indicator of the lubricated surfaces with improved adaptation. Our results indicate that the protein–protein effects help stabilize the structure of adsorbed lysozyme on pHEMA with the raised friction coefficient measured critical for the innovation of contact lens material designs with improved adaptation.

scholarly journals Study of the Properties of Qxide Coatings Formed on Titanium by Plasma Electrolytic Oxidation Method

2020 ◽  
Vol 22 (1) ◽  
pp. 51
Author(s):  
Zh.M. Ramazanova ◽  
M.G. Zamalitdinova
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Plasma Electrolytic Oxidation ◽  
High Wear Resistance ◽  
Material Surface ◽  
Oxide Coatings ◽  
Uncoated Sample ◽  
Oxidation Method ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

The development of the modern industry requires to develop high-performance, environmentally friendly methods for the production of light structural material surface coatings. The use of products and structures made of titanium and its alloys with high wear resistance and corrosion resistance prevails in many industries, in particular in the aerospace industry, shipbuilding, and transport engineering. Nowadays, the application of the plasma electrolytic oxidation method, a promising metal surface treatment method, is of increasing interest. Besides this method is called microarc oxidation. The objective of this work is to study the properties of oxide coatings obtained on titanium alloys under the influence of rapid pulsed effects of the plasma electrolytic oxidation process. Oxide composite coatings were obtained in various electrolyte solutions in this work. Oxide coatings are characterized by high wear resistance. It has been established in tribological tests that the wear resistance of the coating is increased by 2–15 times compared with an uncoated sample. The friction coefficient curves obtained for coated samples show that there is no destruction of the coating to the base. The breaking-in area is marked in the curves. The friction surfaces are adjusted to each other and go to a stable friction mode. The latter results in the friction coefficient decrease and wear rate decrease.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

DURCOMET 100

Alloy Digest ◽  
1993 ◽  
Vol 42 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Mechanical Strength ◽  
Heat Treating ◽  
Corrosion And Wear ◽  
Annealed Condition ◽  
Excellent Corrosion Resistance ◽  
Wide Range ◽  
Very High

Abstract Durcomet 100 is an improved version of Alloy CD-4 MCu with better corrosion and wear resistance. The alloy is used in the annealed condition and possesses excellent corrosion resistance over a wide range of corrosion environments. Mechanical strength is also very high. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating and joining. Filing Code: SS-540. Producer or source: Duriron Company Inc.

Wetting of glass surface using natural surfactants

2020 ◽  
Vol 12 ◽  
Author(s):  
Nihar Ranjan Biswal
Keyword(s):  
Contact Angle ◽  
Glass Surface ◽  
Pure Water ◽  
Amyl Alcohol ◽  
Synthetic Surfactant ◽  
Wide Range ◽  
Different Types ◽  
Natural Surfactants ◽  
Triton X ◽  
Solid Liquid

Background: Surfactant adsorption at the interfaces (solid–liquid, liquid–air, or liquid–liquid) is receiving considerable attention from a long time due to its wide range of practical applications. Objective: Specifically wettability of solid surface by liquids is mainly measured by contact angle and has many practical importances where solid–liquid systems are used. Adsorption of surfactants plays an important role in the wetting process. The wetting behaviours of three plant-based natural surfactants (Reetha, Shikakai, and Acacia) on the glass surface are compared with one widely used nonionic synthetic surfactant (Triton X-100) and reported in this study. Methods: The dynamic contact angle study of three different types of plant surfactants (Reetha, Shikakai and Acacia) and one synthetic surfactant (Triton X 100) on the glass surface has been carried out. The effect of two different types of alcohols such as Methanol and amyl alcohol on wettability of shikakai, as it shows little higher value of contact angle on glass surface has been measured. Results: The contact angle measurements show that there is an increase in contact angle from 47° (pure water) to 67.72°, 65.57°, 68.84°, and 68.79° for Reetha, Acacia, Shikakai, and Triton X-100 respectively with the increase in surfactant concentration and remain constant at CMC. The change in contact angle of Shikakai-Amyl alcohol mixtures are slightly different than that of methanol-Shikakai mixture, mostly there is a gradual increase in contact angle with the increasing in alcohol concentration. Conclusion: There is no linear relationship between cos θ and inverse of surface tension. There was a linear increase in surface free energy results with increase in concentration as more surfactant molecules were adsorbing at the interface enhancing an increase in contact angle.

scholarly journals Estimation of Wear Resistance for Multilayer Coatings Obtained by Nitrogenchroming

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1153
Author(s):  
Ivan Pavlenko ◽  
Jozef Zajac ◽  
Nadiia Kharchenko ◽  
Ján Duplák ◽  
Vitalii Ivanov ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Spectral Analysis ◽  
Friction Coefficient ◽  
Cutting Tools ◽  
Wear Intensity ◽  
Maximum Amount ◽  
Multilayer Coatings ◽  
Wear Depth ◽  
X Ray ◽  
Machine Parts

This article deals with improving the wear resistance of multilayer coatings as a fundamental problem in metal surface treatment, strengthening elements of cutting tools, and ensuring the reliability of machine parts. It aims to evaluate the wear depth for multilayer coatings by the mass loss distribution in layers. The article’s primary purpose is to develop a mathematical method for assessing the value of wear for multilayer steel-based coatings. The study material is a multilayer coating applied to steel DIN C80W1. The research was performed using up-to-date laboratory equipment. Nitrogenchroming has been realized under overpressure in two successive stages: nitriding for 36 h at temperature 540 °C and chromizing during 4 h at temperature 1050 °C. The complex analysis included several options: X-ray phase analysis, local micro-X-ray spectral analysis, durometric analysis, and determination of wear resistance. These analyses showed that after nitrogenchroming, the three-layer protective coating from Cr23C6, Cr7C3, and Cr2N was formed on the steel surface. Spectral analysis indicated that the maximum amount of chromium 92.2% is in the first layer from Cr23C6. The maximum amount of carbon 8.9% characterizes the layer from Cr7C3. Nitrogen is concentrated mainly in the Cr2N layer, and its maximum amount is 9.4%. Additionally, it was determined that the minimum wear is typical for steel DIN C80W1 after nitrogenchroming. The weight loss of steel samples by 25 mg was obtained. This value differs by 3.6% from the results evaluated analytically using the developed mathematical model of wear of multilayer coatings after complex metallization of steel DIN C80W1. As a result, the impact of the loading mode on the wear intensity of steel was established. As the loading time increases, the friction coefficient of the coated samples decreases. Among the studied samples, plates from steel DIN C80W1 have the lowest friction coefficient after nitrogenchroming. Additionally, a linear dependence of the mass losses on the wearing time was obtained for carbide and nitride coatings. Finally, an increase in loading time leads to an increase in the wear intensity of steels after nitrogenchroming. The achieved scientific results are applicable in developing methods of chemical-thermal treatment, improving the wear resistance of multilayer coatings, and strengthening highly loaded machine parts and cutting tools.

scholarly journals Entangling Lattice-Trapped Bosons with a Free Impurity: Impact on Stationary and Dynamical Properties

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 290
Author(s):  
Maxim Pyzh ◽  
Kevin Keiler ◽  
Simeon I. Mistakidis ◽  
Peter Schmelcher
Keyword(s):  
Structural Changes ◽  
Many Body ◽  
Wide Range ◽  
Entropy Measures ◽  
Particle Level ◽  
The Many ◽  
The One ◽  
Tunneling Dynamics ◽  
The Individual ◽  
Trapped Bosons

We address the interplay of few lattice trapped bosons interacting with an impurity atom in a box potential. For the ground state, a classification is performed based on the fidelity allowing to quantify the susceptibility of the composite system to structural changes due to the intercomponent coupling. We analyze the overall response at the many-body level and contrast it to the single-particle level. By inspecting different entropy measures we capture the degree of entanglement and intraspecies correlations for a wide range of intra- and intercomponent interactions and lattice depths. We also spatially resolve the imprint of the entanglement on the one- and two-body density distributions showcasing that it accelerates the phase separation process or acts against spatial localization for repulsive and attractive intercomponent interactions, respectively. The many-body effects on the tunneling dynamics of the individual components, resulting from their counterflow, are also discussed. The tunneling period of the impurity is very sensitive to the value of the impurity-medium coupling due to its effective dressing by the few-body medium. Our work provides implications for engineering localized structures in correlated impurity settings using species selective optical potentials.

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