scholarly journals Continuum thermomechanics of nonlinear micromorphic, strain and stress gradient media

2020 ◽  
Vol 378 (2170) ◽  
pp. 20190169 ◽  
Author(s):  
Samuel Forest
Keyword(s):  
Strain Gradient ◽  
Stress Gradient ◽  
Continuum Theory ◽  
Research Field ◽  
Irreversible Processes ◽  
Current Debate ◽  
Generalized Continua ◽  
Generalized Standard Materials ◽  
New Research ◽  
Continuum Theories

A comprehensive constitutive theory for the thermo-mechanical behaviour of generalized continua is established within the framework of continuum thermodynamics of irreversible processes. It represents an extension of the class of generalized standard materials to higher order and higher grade continuum theories. It reconciles most existing frameworks and proposes some new extensions for micromorphic and strain gradient media. The special case of strain gradient plasticity is also included as a contribution to the current debate on the consideration of energetic and dissipative mechanisms. Finally, the stress gradient continuum theory emerges as a new research field for which an elastic-viscoplastic theory at finite deformations is provided for the first time. This article is part of the theme issue ‘Fundamental aspects of nonequilibrium thermodynamics’.

scholarly journals Finite-deformation second-order micromorphic theory and its relations to strain and stress gradient models

2017 ◽  
Vol 25 (7) ◽  
pp. 1429-1449 ◽  
Author(s):  
Samuel Forest ◽  
Karam Sab
Keyword(s):  
Strain Gradient ◽  
Finite Deformation ◽  
Stress Gradient ◽  
Higher Order ◽  
Second Order ◽  
Stress And Strain ◽  
Dynamical Equations ◽  
Generalized Continua ◽  
Micromorphic Theory ◽  
Gradient Models

Germain’s general micromorphic theory of order [Formula: see text] is extended to fully non-symmetric higher-order tensor degrees of freedom. An interpretation of the microdeformation kinematic variables as relaxed higher-order gradients of the displacement field is proposed. Dynamical balance laws and hyperelastic constitutive equations are derived within the finite deformation framework. Internal constraints are enforced to recover strain gradient theories of grade [Formula: see text]. An extension to finite deformations of a recently developed stress gradient continuum theory is then presented, together with its relation to the second-order micromorphic model. The linearization of the combination of stress and strain gradient models is then shown to deliver formulations related to Eringen’s and Aifantis’s well-known gradient models involving the Laplacians of stress and strain tensors. Finally, the structures of the dynamical equations are given for strain and stress gradient media, showing fundamental differences in the dynamical behaviour of these two classes of generalized continua.

Wspólnota semantyczno-leksykalna języków europejskich. O monografii: А.А. Кретов, О.М. Воевудская, И.А. Меркулова, В.Т. Титов, Единство Европы по данным лексики (Воронеж: Издательский дом ВГУ, 2016, ss. 413 [1])

2018 ◽  
Vol 2 (XXIII) ◽  
pp. 121-133
Author(s):  
Katarzyna Wojan
Keyword(s):  
Comparative Research ◽  
Lexical Semantics ◽  
Research Field ◽  
Original Research ◽  
Linguistic Typology ◽  
Lexical Semantic ◽  
Theoretical Linguistics ◽  
Research Concept ◽  
New Research

This article outlines the original research concept developed and applied by the Voronezh researchers, which brought both quantitative and qualitative results to the field of linguistic comparative research. Their monograph is devoted to the macrotypological unity of the lexical semantics of the languages in Europe. In addition, semantic stratification of Russian and Polish lexis has been analyzed. Their research concept is now known as the “lexical-semantic macrotypological school of Voronezh.” Representatives of this school have created a new research field in theoretical linguistics – a lexical-semantic language macrotypology as a branch of linguistic typology. The monograph has been widely discussed and reviewed in Russia.

Judicial geography as a legal science and academic discipline

2019 ◽  
Vol 5 (4) ◽  
pp. 122-137
Author(s):  
Almaz F. Abdulvaliev
Keyword(s):  
Criminal Law ◽  
Climatic Factors ◽  
Academic Discipline ◽  
Preliminary Investigation ◽  
Criminal Procedure ◽  
Mapping Method ◽  
Research Field ◽  
Point Of View ◽  
Theoretical Development ◽  
New Research

This article presents the conceptual foundations for the formation of a new research field “Judicial Geography”, including the prerequisites for its creation, academic, and theoretical development, both in Russia and abroad. The purpose of the study is to study the possibility of applying geographical methods and means in criminal law, criminal procedure, and in judicial activity in general via the academic direction “Judicial Geography”. The author describes in detail the main elements of judicial geography and its role and significance for such legal sciences, as criminal law, criminal procedure, criminalistics, and criminology among others. The employed research methods allow showing the main vectors of the development of judicial geography, taking into account the previous achievements of Russian and worldwide academics. The author indicates the role and place of judicial geography in the system of legal sciences. This study suggests a concept of using scientific geographical methods in the study of various legal phenomena of a criminal and criminal-procedural nature when considering the idea of building judicial bodies and judicial instances, taking into account geographical and climatic factors. In this regard, the author advises to introduce the special course “Judicial Geography”, which would allow law students to study the specifics of the activities of the judiciary and preliminary investigation authorities from a geographical point of view, as well as to use various geographical methods, including the mapping method, in educational and practical activities. The author concludes that forensic geography may become a new milestone for subsequent scientific research in geography and jurisprudence.

USE OF STRAIN GRADIENT THEORY FOR MODELING THE SIZE-DEPENDENT PULL-IN OF ROTATIONAL NANO-MIRROR IN THE PRESENCE OF MOLECULAR FORCE

2013 ◽  
Vol 27 (18) ◽  
pp. 1350083 ◽  
Author(s):  
Y. TADI BENI ◽  
M. ABADYAN
Keyword(s):  
Strain Gradient ◽  
Continuum Theory ◽  
Strain Gradient Theory ◽  
Gradient Theory ◽  
Cross Sectional ◽  
Size Dependent ◽  
Proposed Model ◽  
Molecular Force ◽  
Intrinsic Material Length ◽  
Material Length

Experiments reveal that mechanical behavior of nanostructures is size-dependent. Herein, the size dependent pull-in instability of torsional nano-mirror is investigated using strain gradient nonclassic continuum theory. The governing equation of the mirror is derived taking the effect of electrostatic Coulomb and molecular van der Waals (vdW) forces into account. Variation of the rotation angle of the mirror as a function of the applied voltage is obtained and the instability parameters i.e., pull-in voltage and pull-in angle are determined. Nano-mirrors with square and circular cross-sectional beams are investigated as case studies. It is found that when the thickness of the torsional nano-beam is comparable with the intrinsic material length scales, size effect can substantially increase the instability parameters of the rotational mirror. Moreover, the effect of vdW forces on the size-dependent pull-in instability of the system is discussed. The proposed model is able to predict the experimental results more accurately than the previous classic models and reduce the gap between experiment and previous theories.

Improvement of Superplasticity in Fine-Grained Oxide Ceramics Based on the Concept of Grain Boundary Plasticity

2016 ◽  
Vol 838-839 ◽  
pp. 34-40
Author(s):  
Hidehiro Yoshida ◽  
Koji Morita ◽  
Byung Nam Kim ◽  
Koji Matsui ◽  
Yuichi Ikuhara ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Atomic Structure ◽  
Nucleation And Growth ◽  
Phenomenological Analysis ◽  
Research Field ◽  
Oxide Ceramics ◽  
Cavity Nucleation ◽  
Fine Grained ◽  
Experimental Strain ◽  
New Research

Superplasticity in fine-grained oxide ceramics has been generally elucidated on the basis of their experimental strain rate-flow stress relationship and phenomenological analysis of cavity nucleation and growth. It has been widely accepted that the high temperature superplastic flow and failure in ceramics is significantly influenced by the atomic structure and chemistry of grain boundaries. Such phenomenon cannot be explained based on the classical phenomenological analysis. Our research group has therefore proposed to establish a new research field, grain boundary plasticity, to describe the superplastic deformation related to the grain boundary atomic structure. This paper aims to point out the importance of the atomistic analysis of grain boundary to develop new superplastic ceramics.

A Finite-Temperature Continuum Theory Based on Interatomic Potentials

2005 ◽  
Vol 127 (4) ◽  
pp. 408-416 ◽  
Author(s):  
H. Jiang ◽  
Y. Huang ◽  
K. C. Hwang
Keyword(s):  
Temperature Dependence ◽  
Finite Temperature ◽  
Interatomic Potential ◽  
Coefficient Of Thermal Expansion ◽  
Harmonic Approximation ◽  
Continuum Theory ◽  
Single Wall Carbon Nanotubes ◽  
Interatomic Potentials ◽  
Atomistic Models ◽  
Continuum Theories

There are significant efforts to develop continuum theories based on atomistic models. These atomistic-based continuum theories are limited to zero temperature (T=0K). We have developed a finite-temperature continuum theory based on interatomic potentials. The effect of finite temperature is accounted for via the local harmonic approximation, which relates the entropy to the vibration frequencies of the system, and the latter are determined from the interatomic potential. The focus of this theory is to establish the continuum constitutive model in terms of the interatomic potential and temperature. We have studied the temperature dependence of specific heat and coefficient of thermal expansion of graphene and diamond, and have found good agreements with the experimental data without any parameter fitting. We have also studied the temperature dependence of Young’s modulus and bifurcation strain of single-wall carbon nanotubes.

Perceptions and pathways of resilience in Addis Ababa

2018 ◽  
Vol 36 (4) ◽  
pp. 337-352
Author(s):  
Nicole Baron ◽  
Zegeye Cherenet
Keyword(s):  
Addis Ababa ◽  
Research Field ◽  
Change Resistance ◽  
Theory Approach ◽  
Expert Interviews ◽  
Urban Resilience ◽  
Initial Attempt ◽  
Content Type ◽  
African Perspective ◽  
New Research

Purpose Resilience has recently attracted widespread interest in the field of urban planning and theory. However, the research that has been conducted on urban resilience in Africa has major theoretical and methodological gaps. This can lead to problems when designing and implementing resilience strategies there. Understanding African perspectives can be a way of tackling these. The paper aims to discuss these issues. Design/methodology/approach Using the example of Addis Ababa, Ethiopia, this paper analyses expert interviews based on a grounded theory approach. The goal is to explore locally specific perceptions of and pathways to urban resilience. By comparing these findings to those reported in the existing literature, differences and overlaps are identified. Findings This study provides evidence for the existence of locally specific perceptions of and pathways to urban resilience. Furthermore, it identifies urban development pathways such as complete urban makeover (tabula rasa) and complete negation of change (resistance). Research limitations/implications Because this study uses Addis Ababa as a singular case and expert interviews as method, it rather represents an initial attempt at exploring a new research field than claiming generalisability. Its quality and significance lie in its discursive approach and theory formation. Practical implications This exemplary study from Ethiopia demonstrates that a regionally specific understanding of urban resilience is valuable for the design and implementation of urban resilience strategies. Originality/value This study offers unique insights into urban resilience from an African perspective and into the manifestation of urban resilience in Addis Ababa.

Research Approaches in Computer-Supported Collaborative Learning

2013 ◽  
Vol 9 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Tharrenos Bratitsis ◽  
Stavros Demetriadis
Keyword(s):  
Collaborative Learning ◽  
Research Field ◽  
Computer Supported Collaborative Learning ◽  
Research Issues ◽  
Online Distance Education ◽  
Theoretical Perspectives ◽  
History Of ◽  
How People Learn ◽  
Online Distance ◽  
New Research

Computer Supported Collaborative Learning (CSCL) is concerned with how people learn when working and interacting in groups with the assistance of ICTs. The field involves collaboration, computer mediation, online – distance education which raises interesting theoretical considerations regarding the actual studying of learning within CSCL settings. Being a rather interdisciplinary research field in nature, it has a long history of controversy about its theory, methods, and definition. In this editorial, through a quick review of the literature the diversity of issues examined under the CSCL research field becomes obvious. Moreover, an attempt to categorize these research issues is made. In this vein, the four interesting contributions of this Special Issue, regarding theoretical perspectives and issues of research of the field, are introduced. They comply with the distinguished categories, but they open new research borders as well.

scholarly journals Analysis of the Most-Cited Systematic Review or Meta-Analysis in Acupuncture Research

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Ying He ◽  
Yuxi Li ◽  
Juan Li ◽  
Ning Li ◽  
Yonggang Zhang ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Meta Analysis ◽  
Developed Countries ◽  
Research Field ◽  
Maryland School ◽  
The Usa ◽  
Acupuncture Research ◽  
New Research ◽  
Meta Analyses ◽  
The University

Objectives. The aim of the current study was to analyze the 100 most-cited systematic reviews or meta-analyses in the field of acupuncture research. Methods. The Web of Science Core Collection was used to retrieve lists of 100 most-cited systematic reviews or meta-analyses in the field of acupuncture research. Two authors screened literature, extracted data, and analyzed the results. Results. The citation number of the 100 most-cited systematic reviews or meta-analyses varied from 65 to 577; they were published between 1989 and 2018. Fourteen authors published more than 1 study as the corresponding author and 10 authors published more than 1 study as the first author. In terms of the corresponding authors, Edzard Ernst and Linde Klaus published the most systematic reviews/meta-analyses (n = 7). The USA published most of the systematic reviews or meta-analyses (n = 24), followed by England (n = 23) and China (n = 14). Most institutions with more than 1 study were from England (4/13). The institutions with the largest numbers of most-cited systematic reviews or meta-analyses were the Technical University of Munich in Germany, the University of Maryland School of Medicine in the USA (n = 8), the Universities of Exeter and Plymouth in England (n = 6), and the University of Exeter in England (n = 6). The journal with the largest number of most-cited systematic reviews or meta-analyses was the Cochrane Database of Systematic Reviews (n = 20), followed by Pain (n = 6). Conclusion. Our study reveals that the 100 most-cited systematic reviews or meta-analyses in the acupuncture research field are mostly from high impact factor journals and developed countries. It will help researchers follow research hot spots, broaden their research scope, expand their academic horizons, and explore new research ideas, thereby improving the quality of acupuncture research.

scholarly journals Percepcja i projekcja krajobrazu: teorie, zastosowania, oczekiwania = Perception and projection of the landscape: theories, applications, expectations

2019 ◽  
Vol 91 (3) ◽  
pp. 365-384
Author(s):  
Tadeusz Jan Chmielewski ◽  
Szymon Chmielewski ◽  
Agnieszka Kułak
Keyword(s):  
Scientific Work ◽  
Research Field ◽  
Practical Application ◽  
Landscape Perception ◽  
Knowledge Based ◽  
Space Projection ◽  
Surrounding Space ◽  
New Research ◽  
Opening Up

The human species transforms the landscape to meet its needs, but landscape resources and valuable features at the same time affect wellbeing in the context of human activity. In these mutually conditioned interactions, two processes playing a key role are the so-called landscape perception and landscape projection. This article presents: (1) a review of theories playing a key role in the development of knowledge on landscape perception; (2) the basis for landscape projection as a logical and creative continuation of perception processes; (3) an outline of the theory of physiognomic landscape structure and of possibilities for it to gain practical application; (4) the results of the first Polish research into the public’s expectations where quality of the landscape is concerned. Perception of the landscape entails the receipt of stimuli from surrounding space with the help of the senses. It serves primarily in knowledge-based transformation of landscape systems, in a manner that meets ever-more exacting requirements on the part of society when it comes to living in an environment of the highest quality. Only a little scientific work has been devoted to the process of landscape projection. This is therefore a new research field, just opening up, which has the potential to give rise to a group of space-projection theories.

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