22nd Leeds-Lyon Symposium on Tribology “The Third Body Concept : Interpretation of Tribological Phenomena”

Keyword(s):  
2017 ◽  
Vol 23 (3) ◽  
pp. 420-432 ◽  
Author(s):  
Pavel Krejčí ◽  
Adrien Petrov

The third-body concept is a pragmatic tool used to understand the friction and wear of sliding materials. The wear particles play a crucial role in this approach and constitute the main part of the third-body. This paper aims to introduce a mathematical model for the motion of a third-body interface separating two surfaces in contact. This model is written in accordance with the formalism of hysteresis operators as solution operators of the underlying variational inequalities. The existence result for this dynamical problem is obtained by using a priori estimates established for Faedo–Galerkin approximations, and some more specific techniques such as anisotropic Sobolev embedding theory.


Wear ◽  
2007 ◽  
Vol 262 (7-8) ◽  
pp. 949-957 ◽  
Author(s):  
N. Fillot ◽  
I. Iordanoff ◽  
Y. Berthier

2015 ◽  
Vol 640 ◽  
pp. 1-12 ◽  
Author(s):  
Jean Denape

The third body concept is a pragmatic tool for analyzing and understanding the friction and wear of sliding materials. This approach is based on the dominating role played by the wear particles under dry sliding conditions. These particles constitute the major part of what is called the third body. The third body concept was introduced by Maurice Godet in the middle of the 70’s and developed by Yves Berthier since the end of the 80’s who added complementary conceptual tools as the tribological triplet, the accommodation mechanisms and the tribological circuit. The aim of this paper is to give a synthetic view of these concepts, which involves mechanical, material and physicochemical subjects. Concrete examples and case studies from various practical applications are given to illustrate the validity and the efficiency of such a phenomenological approach.


2021 ◽  
Vol 133 (3) ◽  
Author(s):  
Marilena Di Carlo ◽  
Simão da Graça Marto ◽  
Massimiliano Vasile

AbstractThis paper presents a collection of analytical formulae that can be used in the long-term propagation of the motion of a spacecraft subject to low-thrust acceleration and orbital perturbations. The paper considers accelerations due to: a low-thrust profile following an inverse square law, gravity perturbations due to the central body gravity field and the third-body gravitational perturbation. The analytical formulae are expressed in terms of non-singular equinoctial elements. The formulae for the third-body gravitational perturbation have been obtained starting from equations for the third-body potential already available in the literature. However, the final analytical formulae for the variation of the equinoctial orbital elements are a novel derivation. The results are validated, for different orbital regimes, using high-precision numerical orbit propagators.


2002 ◽  
Vol 11 (3) ◽  
pp. 288-293 ◽  
Author(s):  
Gui-Zhen Xu ◽  
Jia-Jun Liu ◽  
Zhong-Rong Zhou

2015 ◽  
Vol 16 (25) ◽  
pp. 168
Author(s):  
Vilma Moreira dos Santos ◽  
Thiago Veloso Vitral ◽  
Alessandra Palhares

<p>O Projeto <strong>Memorial da Imprensa de Uberaba: criação da Hemeroteca Digital do Triângulo Mineiro e Alto Paranaíba </strong>constitui, provavelmente, o maior investimento do estado de Minas Gerais em um projeto individual na área de preservação de acervos documentais históricos. O projeto conta com o financiamento da Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG). Foi concebido e vem sendo executado por parceria firmada entre a Secretaria de Estado de Ciência, Tecnologia e Ensino Superior (SECTES/MG) e a Secretaria de Estado de Cultura (SEC/MG), por meio do Arquivo Público Mineiro (APM), órgão coordenador do Projeto e da Superintendência de Bibliotecas Públicas (SUB). Conta ainda com a participação do Arquivo Público de Uberaba. A partir das diretrizes de regionalização da política cultural do Estado, o resultado principal do projeto será a implantação de um polo de digitalização de acervos documentais históricos no Arquivo Público de Uberaba, que deverá atuar como órgão catalizador e executor de projetos de digitalização nas regiões acima mencionadas. O projeto se fundamenta nas metodologias de organização, preservação e digitalização de acervos documentais preconizadas pelo <strong>Programa Conservação Preventiva em Bibliotecas e Arquivos</strong>, nas recomendações do Conselho Nacional de Arquivos (CONARQ) e nas regras do Código de Catalogação Anglo-americano (CCAA2).</p><p><strong><br /></strong></p><p><strong>Abstract</strong></p><p>“The Printing Press Memorial of Uberaba: the creation of the newspapers´ digital library of Triângulo Mineiro and Alto Paranaíba (Minas Gerais, Brazil)” is probably, the biggest project in the field of historical collections preservation ever funded by the Fundação de Amparo à Pesquisa do Estado de Minas Gerais – FAPEMIG. The project was conceived and has been carried out by the Secretaria de Estado de Ciência, Tecnologia e Ensino Superior, along with the Secretaria de Estado de Cultura, through the participation of the Arquivo Público Mineiro, the coordinating body, and the Superintendência de Bibliotecas Públicas. The<em> </em>Arquivo Público de Uberaba is the third body involved with the implementation of the project. In accordance with the regionalization policies of the State, the main achievement of the project shall be the creation of a digitalization center of historical collections in the Arquivo Público de Uberaba. This institution shall act as a regional agency for the development of digitalization projects in the regions of Triângulo Mineiro and Alto Paranaíba. The project is based on the methodologies of organization, preservation and digitalization of historical collections, recommended by the Programa de Conservação Preventiva em Bibliotecas e Arquivos, the guidelines of the Conselho Nacional de Arquivos<em> </em>(CONARQ) and the Anglo American Cataloguing Rules (AACR2).</p><p><strong>Keywords</strong>: Digitalization of Historical collections; Preservation of Historical Collections; Digital Libraries.</p>


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