scholarly journals The role of scale factor in the formation of prod-uct properties under the action of surface modifi-cation

2021 ◽  
pp. 97
Author(s):  
Irina Doschechkina
Keyword(s):  
Surface Layer ◽  
Large Scale ◽  
Materials Science ◽  
Tensile Deformation ◽  
Decisive Role ◽  
Ion Bombardment ◽  
Scale Factor ◽  
Low Carbon ◽  
Solid State Physics ◽  
Modified Layer

Based on theoretical and experimental research in the fields of solid-state physics and physical materials science, it is proved that the surface layer of a solid body, which is deformed, is an independent functional subsystem and radically affects large-scale levels of plastic flow and destruction of the product as a whole. As is known, the most effective method of improving the performance of products is the grinding of grain, because it is the grain boundary (substructural) mechanism of strengthening which provides an increase in the structural strength of the product. In this regard, special attention is paid to submicro- and nano-structuring of the surface. Goal. The aim of the work is to study the process of structure formation of the surface layer under the action of ion bombardment (IB) and its effect on the properties of products taking into account the scale factor. To achieve this goal, the following tasks were set: to evaluate the characteristics of the surface microstructure after IB and to study its tensile behavior in cylindrical and flat samples of low-carbon steel in order to take into account the scale factor in changing their properties. The submicro-structuring of the surface by ion bombardment is carried out in the work and its influence on the behavior of products during tensile deformation is investigated. It is established that the presence of a thin modified layer (with a constant core) significantly changes the properties of the product under force. The decisive role belongs to the contribution of the surface layer (scale factor) – the ratio of the area of the modified layer to the volume of the product: if it is <1 the effect of hardening is better realized while maintaining plasticity, and if ˃ 1, it is a significant effect of plasticization which maintains (or even increases) hardening.

scholarly journals Global outlook on large-scale nuclear power development strategies

2021 ◽  
Vol 7 (4) ◽  
pp. 263-270
Author(s):  
Evgeny O. Adamov ◽  
Valeriy I. Rachkov ◽  
Andrey A. Kashirsky ◽  
Alexander I. Orlov
Keyword(s):  
Nuclear Power ◽  
Large Scale ◽  
Fuel Cycle ◽  
Decisive Role ◽  
Energy System ◽  
Electricity Sector ◽  
Low Carbon ◽  
Power Development ◽  
Energy Mix ◽  
Nuclear Power Development

As of today, nuclear power together with hydropower provides three-quarters of global low-carbon electricity generation. Over the past 60 years since the time of its inception, the use of nuclear power has reduced CO2 emissions by over 60 gigatonnes. There is no doubt that nuclear power can play a major, and maybe even a decisive role in decarbonizing the electricity sector, as it is evident from the current energy mix of some European countries, especially France, and major economic powers like the Unites States, Russia and South Korea. It is also evident that in most advanced economies nuclear power has entered a phase of gradual decline with little new investment coming into new projects, regardless of the world’s desperate need for more low-carbon electricity. Although existing reactor and their corresponding fuel cycle technologies have enabled the global nuclear power fleet to reach ~ 400 GWe of net installed capacity, there is growing concern that the scale of NPP shutdowns expected in Europe and North America could offset new capacity additions in Asian markets. Theoretically, renewable energy could fill the void left by reactors taken offline but there is strong evidence that the potential of wind and solar for global decarbonization is limited by material, land and economic constraints. Large-scale renewable systems would also require massive energy storage capacity that would hamper economic sustainability of the energy supply for developing countries. Taking into account the potential benefits of developing nuclear power, some countries are determined to expand its share in their energy mix through technological innovation and application of new strategies, directed at improving or completely resolving current issues related to economics, environmental concerns or non-proliferation of nuclear weapons. There are many states in the world today pursuing some sort of nuclear power development. A limited number of countries envision expanding or transforming their nuclear energy system using truly game-changing strategies based on innovative reactor, fuel cycle and waste management technologies. The focus of this paper is to give an overview of the approaches to large-scale nuclear power development being applied today in Russia, China, USA and India.

Evolution of Metastable Structures in Bimetallic Catalysts from Microscopy and Machine-Learning Molecular Dynamics

2020 ◽  
Author(s):  
Jin Soo Lim ◽  
Jonathan Vandermause ◽  
Matthijs A. van Spronsen ◽  
Albert Musaelian ◽  
Christopher R. O’Connor ◽  
...  
Keyword(s):  
Machine Learning ◽  
Molecular Dynamics ◽  
Large Scale ◽  
Materials Science ◽  
Complete Characterization ◽  
Layer By Layer ◽  
Surface Restructuring ◽  
Metastable Structures ◽  
Mechanistic Investigation ◽  
Underlying Mechanisms

Restructuring of interface plays a crucial role in materials science and heterogeneous catalysis. Bimetallic systems, in particular, often adopt very different composition and morphology at surfaces compared to the bulk. For the first time, we reveal a detailed atomistic picture of the long-timescale restructuring of Pd deposited on Ag, using microscopy, spectroscopy, and novel simulation methods. Encapsulation of Pd by Ag always precedes layer-by-layer dissolution of Pd, resulting in significant Ag migration out of the surface and extensive vacancy pits. These metastable structures are of vital catalytic importance, as Ag-encapsulated Pd remains much more accessible to reactants than bulk-dissolved Pd. The underlying mechanisms are uncovered by performing fast and large-scale machine-learning molecular dynamics, followed by our newly developed method for complete characterization of atomic surface restructuring events. Our approach is broadly applicable to other multimetallic systems of interest and enables the previously impractical mechanistic investigation of restructuring dynamics.

The Chemical Bond Across the Periodic Table: Part 1 – First Row and Simple Metals

2020 ◽  
Author(s):  
Gabriel Freire Sanzovo Fernandes ◽  
Leonardo dos Anjos Cunha ◽  
Francisco Bolivar Correto Machado ◽  
Luiz Ferrão
Keyword(s):  
Physical Chemistry ◽  
Chemical Bond ◽  
Materials Science ◽  
Chemical Elements ◽  
Orbital Theory ◽  
Solid State Physics ◽  
Band Theory ◽  
Van Der Waals Clusters ◽  
Earth Systems ◽  
Chemical Content

<p>Chemical bond plays a central role in the description of the physicochemical properties of molecules and solids and it is essential to several fields in science and engineering, governing the material’s mechanical, electrical, catalytic and optoelectronic properties, among others. Due to this indisputable importance, a proper description of chemical bond is needed, commonly obtained through solving the Schrödinger equation of the system with either molecular orbital theory (molecules) or band theory (solids). However, connecting these seemingly different concepts is not a straightforward task for students and there is a gap in the available textbooks concerning this subject. This work presents a chemical content to be added in the physical chemistry undergraduate courses, in which the framework of molecular orbitals was used to qualitatively explain the standard state of the chemical elements and some properties of the resulting material, such as gas or crystalline solids. Here in Part 1, we were able to show the transition from Van der Waals clusters to metal in alkali and alkaline earth systems. In Part 2 and 3 of this three-part work, the present framework is applied to main group elements and transition metals. The original content discussed here can be adapted and incorporated in undergraduate and graduate physical chemistry and/or materials science textbooks and also serves as a conceptual guide to subsequent disciplines such as quantum chemistry, quantum mechanics and solid-state physics.</p>

Continuum Description of the Time- and Strain-Dependent Poisson’s Ratio of Ligament Under Finite Deformation

2013 ◽  
Author(s):  
Aaron M. Swedberg ◽  
Shawn P. Reese ◽  
Steve A. Maas ◽  
Benjamin J. Ellis ◽  
Jeffrey A. Weiss
Keyword(s):  
Large Scale ◽  
Mechanical Response ◽  
Tensile Deformation ◽  
Large Strain ◽  
Fiber Direction ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Strain Dependent

Ligament volumetric behavior controls fluid and thus nutrient movement as well as the mechanical response of the tissue to applied loads. The reported Poisson’s ratios for tendon and ligament subjected to tensile deformation loading along the fiber direction are large, ranging from 0.8 ± 0.3 in rat tail tendon fascicles [1] to 2.98 ± 2.59 in bovine flexor tendon [2]. These Poisson’s ratios are indicative of volume loss and thus fluid exudation [3,4]. We have developed micromechanical finite element models that can reproduce both the characteristic nonlinear stress-strain behavior and large, strain-dependent Poisson’s ratios seen in tendons and ligaments [5], but these models are computationally expensive and unfeasible for large scale, whole joint models. The objectives of this research were to develop an anisotropic, continuum based constitutive model for ligaments and tendons that can describe strain-dependent Poisson’s ratios much larger than the isotropic limit of 0.5. Further, we sought to demonstrate the ability of the model to describe experimental data, and to show that the model can be combined with biphasic theory to describe the rate- and time-dependent behavior of ligament and tendon.

scholarly journals Hydropower, Geothermal, and Ocean Energy

MRS Bulletin ◽  
2008 ◽  
Vol 33 (4) ◽  
pp. 389-395 ◽  
Author(s):  
Ralph E.H. Sims
Keyword(s):  
Renewable Energy ◽  
Large Scale ◽  
New Technologies ◽  
Materials Science ◽  
Development Stage ◽  
Design Development ◽  
Ocean Energy ◽  
Improve Design ◽  
And Performance ◽  
Improve Reliability

AbstractSome forms of renewable energy have long contributed to electricity generation, whereas others are just emerging. For example, large-scale hydropower is a mature technology generating about 16% of global electricity, and many smaller scale systems are also being installed worldwide. Future opportunities to improve the technology are limited but include upgrading of existing plants to gain greater performance efficiencies and reduced maintenance. Geothermal energy, widely used for power generation and direct heat applications, is also mature, but new technologies could improve plant designs, extend their lifetimes, and improve reliability. By contrast, ocean energy is an emerging renewable energy technology. Design, development, and testing of a myriad of devices remain mainly in the research and development stage, with many opportunities for materials science to improve design and performance, reduce costly maintenance procedures, and extend plant operating lifetimes under the harsh marine environment.

Up Close: Science of Materials at Trinity College, University of Dublin

MRS Bulletin ◽  
1990 ◽  
Vol 15 (5) ◽  
pp. 35-39
Author(s):  
John M. Kelly ◽  
John McGilp
Keyword(s):  
Final Section ◽  
Materials Science ◽  
Trinity College ◽  
Applied Physics ◽  
Solid State Physics ◽  
Close Collaboration ◽  
Surfaces And Interfaces ◽  
Common Interests ◽  
New Research ◽  
The 19Th Century

Materials Science at Trinity College, University of Dublin, Ireland, has a distinguished past as well as a promising future. Trinity College published the first book on optics in English by Molyneux (1692). The work of Hamilton, Lloyd, Fitzgerald and others in the 19th century are impressive antecedents for today's research as well, which now enjoys broader horizons and new research opportunities due to major funding by the European Community (EC) and other agencies.In the Departments of Chemistry and Pure and Applied Physics, internationally recognized research groups are pursuing materials-oriented research in laser physics and nonlinear optics, surfaces and interfaces, magnetic materials, polymers, and theoretical solid-state physics and chemistry.The current research, described in the following two sections, has for many years resulted from close collaboration in the materials area among researchers in both departments. Common interests have led the departments to establish an honors degree course in the science of materials. The final section discusses the aims of this course.

Design and Application of Automatic Monitoring System in Side Slope

2011 ◽  
Vol 243-249 ◽  
pp. 2613-2617 ◽  
Author(s):  
Xiu Guang Song ◽  
Zheng Ma ◽  
Hong Bo Zhang ◽  
Qian Wang ◽  
Pei Zhi Zhuang
Keyword(s):  
Large Scale ◽  
Surface Displacement ◽  
Automatic Monitoring ◽  
Scale Construction ◽  
Low Carbon ◽  
Soil Pressure ◽  
Monitoring Method ◽  
Automatic Monitoring System ◽  
Side Slope ◽  
Project Construction

The field monitoring of dangerous landslide is an important measure for guaranteeing its safety, especially when surrounded by large-scale construction. The landslide located nearby a reservoir in Shandong province. To guarantee construction safety, we adopted the automatic monitoring method for monitoring surface displacement and the internal soil pressure. The whole system uses solar power to provide energy and uses GPRS to transfer data. This system not only can provide reliable information for project construction, but also promote the application of environmentally friendly, low carbon in the monitoring field of civil engineering.

A Study on Tensile Deformation Features of Ni-Based Super-Alloy Prepared by EB-PVD

2011 ◽  
Vol 55-57 ◽  
pp. 251-256
Author(s):  
Li Ma ◽  
Ting Zhang ◽  
Xiao Li ◽  
Zhao Hui Hu
Keyword(s):  
Physical Vapor Deposition ◽  
Large Scale ◽  
Tensile Deformation ◽  
Alloy Sheet ◽  
Dislocation Climb ◽  
Dislocation Glide ◽  
Double Phase ◽  
Transmission Electron ◽  
Deformation Features ◽  
Super Alloy

Large-scale Ni-based super-alloy sheet has been prepared by electron beam physical vapor deposition (EB-PVD). Microstructure and the dislocation structures in the γ-γ′ double phase alloy under different temperature after tensile strain are studied with Transmission electron microscopy (TEM). The results show that the dislocation glide in single slip system and shearing mechanics, the dislocation climb with part shearing, absolute dislocation climb and cross slip, dislocation round are a course of the interacting degree between dislocation and γ′ phase gradually weakened under the tensile temperature from room temperature to high temperature, so as to decrease materials strength and increase plasticity.

scholarly journals A Fuzzy-ANP Approach for Comprehensive Benefit Evaluation of Grid-Side Commercial Storage Project

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1129
Author(s):  
Huijia Yang ◽  
Weiguang Fan ◽  
Guangyu Qin ◽  
Zhenyu Zhao
Keyword(s):  
Energy Storage ◽  
Evaluation System ◽  
Large Scale ◽  
Stable Operation ◽  
Low Carbon ◽  
Profit Model ◽  
Benefit Evaluation ◽  
Comprehensive Benefit ◽  
Grid Side ◽  
Business Mode

With the increasing demand for clean and low-carbon energy, high proportion of renewable energy has been integrated into the receiving-end grid. The grid-side energy storage project can ensure the safe and stable operation of the grid, but it still faces many problems, such as high initial investment, difficult operation and maintenance, unclear profit model, lack of business mode. Therefore, it is of great significance to evaluate the comprehensive benefit of energy storage projects in order to guide the sustainable development of large-scale energy storage projects and power system. By studying the technical and economic characteristics of energy storage, this paper establishes a comprehensive evaluation system from four dimensions of energy efficiency, economic, social, and environmental benefit. Combined with typical business modes and determining the subdivision index system of different modes, the comprehensive benefit evaluation model of grid-side commercial storage project based on Fuzzy-Analytic Network Process (ANP) approach is established. Empirical analysis of a 100-megawatt storage project is carried out to evaluate the project benefits comprehensively, the potential problems of the market development and business mode of the grid-side large-scale storage project are discussed, and the future development orientation and suggestions are put forward.

Increasing Hardness of Surface Layer of Low-Carbon Steel by Account of Plasma Treatment of Coating Modification

2021 ◽  
Vol 316 ◽  
pp. 794-802
Author(s):  
Andrey E. Balanovsky ◽  
Van Trieu Nguyen
Keyword(s):  
Surface Layer ◽  
Thermal Treatment ◽  
Plasma Treatment ◽  
Plasma Heating ◽  
High Surface ◽  
Surface Hardness ◽  
High Hardness ◽  
Diffusion Region ◽  
Low Carbon ◽  
Wide Range

The Purpose of paper is to conduct studies to assess the possibility of increasing the hardness of the surface layer of steel St3 grade by plasma heating of the applied surface coating containing powder alloy PR-N80X13S2R. Mixtures of pasta were divided into 2 groups: for furnace chemical-thermal treatment and plasma surface melting. The study of the microstructure showed a difference in the depth of the saturated layer, depending on the processing method, during chemical-thermal treatment-1 mm, plasma fusion - 2 mm. The results of measuring the surface micro-hardness showed that, the obtained coating from a mixture of PR-N80X13S2R + Cr2O3 + NH4Cl has a uniform high surface hardness (31-64 HRC), from a mixture of only PR-N80X13S2R - the surface hardness varies in a wide range (15-60 HRC). The study of the microhardness of the cross section of the surface layer showed that, the diffusion region: from a mixture of powder PR-N80X13S2R + Cr2O3 + NH4Cl has uniform hardness (450-490 HV); from a mixture of PR-N80X13S2R - hardness increases in the depth of the molten region (from 300 to 600 HV), and sharply decreases in the heat affected zone (210-170 HV). The use of PR-N80X13S2R alloy powder as the main component in the composition of the paste deposited on the St3 surface during plasma treatment leads to the formation of a doped surface layer with high hardness.

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