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A Discussion on the Physical Interpretation of Measurements of Tribological Wear

Sadowski Jan

Tribologia

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2021

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nr 1

27--37

EN

Physical sense and practical significance of major measurements of tribological wear are analysed here. Definitions and methods of assessing these measurements are proposed on the basis of the laws of energy and mass conservation. Contributions of energy and displacement of particular friction forces corresponding to each element of a friction couple are addressed. Energy expenditure that causes wear is introduced into the definition of wear resistance. Planning and thermodynamic analysis of a tribological experiment and the application of thermodynamic concepts and quantities to the description and the interpretation of results are recommended. The author believes application of wear measures that have an unequivocal physical interpretation will limit problems with the incomparability and the irreproducibility of tribological results and issues with transferring them to real objects.

PL

W niniejszej pracy zanalizowano senes fizyczny i praktyczne znaczenie ważniejszych miar zużycia tribologicznego. Zaproponowano definicje i sposoby oceny tych miar w oparciu o zasady zachowania energii i masy. Uwzględniono w nich udział energii i przemieszczenia poszczególnych sił tarcia, które przypadają na każdy z elementów pary ciernej. Do definicji odporności na zużycie wprowadzono nakład energii, który je spowodował. Zalecono zaplanowanie eksperymentu tribologicznego z jego analizą termodynamiczną oraz wykorzystanie pojęć i wielkości termodynamicznych do opisu i interpretacji uzyskanych wyników. Zdaniem autora stosowanie miar zużycia mających jednoznaczną interpretację fizyczną ograniczy problemy nieporównywalności i nie odtwarzalności wyników badań tribologicznych oraz trudności ich przenoszenia na obiekty rzeczywiste.

2

Quality assurance in the european higher education area

Karkoszka T.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

759-766

EN

Purpose of the presented paper aims at motivating the necessity of assuring the quality in higher education by implementation of the quality management system Design/methodology/approach covers the characterisation of strategic aims of the higher education, mostly - the principles of performance of higher education systems making possible the European cooperation and the comparability of the mechanisms and the results of activity. Findings of the carried out research are as follows: implementation of the rules of higher education system should ensure: level of education being the quality standard, coherent educational system allowing for mobile choice of the place of education, universal accessibility of education, lifelong education as well as recognition of knowledge, skills and qualifications in all countries of European Union. Practical implications: refers to any university which wants to assure quality in education by taking part in the Bologna Process. Originality/value: of the presented paper belongs to the idea and the progress of the Bologna Process as a European widespread venture aiming at establishing the European Higher Education Area and determination of the directions of development of higher education and the research systems.

3

Z problematyki porównywalności kartogramów

Leonowicz A.

Polski Przegląd Kartograficzny

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2002

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T. 34, nr 1

22-33

PL

Artykuł jest próbą odpowiedzi na pytanie, jakie warunki powinny spełniać kartogramy, aby możliwe było poprawne ich porównywanie. Przedstawione czynniki. które mogą mieć wpływ na wizualną ocenę podobieństwa tych map.

EN

Process of choropleth map comparison bases on two elements: space units and class intervals. Basing on them one can formulate conditions of optimaln comparability: similar pattern of space units on both maps, the same number of classes, the same and method of class selection, The question of class selection, which would provide for comparable maps has not been finally solved yet. In the selection of class intervals several hints can be followed: 1) class interval system with approximately equal nymbers of observations in each category should be chosen, which prevents empty classes in case of different statistical distribution; 2) division methods should base on statistic measures treating each statistical sets as a whole, rather than on absolute values, different for each set; 3) a unified measure should be used for describing class limit values, regardless on the denomination of mapped data. These conditions are best met by two types of class selection methods: arithmetic mean and quantilies is the first; the second bases on standard deviation units. Their advantages are combined in the method proposed by A. Dąbrowski (1980). His division bases on arithmetic mean and quantiles, with class limits modified so that they can be set as standard deviation units. The method of M.S. Monmonier (1975) is an attempt to optimise the class selection methods for choropleth map comparison. It sets class limits at intervals, which stress similarities between maps. Effects of classification method on the correlation of presented phenomena has been researched by J.Olson (1972a, 1972b). In the research of comparability it is important to consider map perception by users. Process of visual comparison of choropleth maps has been researched in many experiments (H.H.McCarty, N.E. Salisbury 1961; J. C. Muller 1976a, 1980; R. Lloyd, T. Steinke 1976, 1981, 1983; M. P. Peterson 1979). Their results show, that visual judgement of map similarity does not always confirm to the correlation calculated for particular maps. This process is not fully random. Among the factors, which shape user perception are the following: similar distribution of phenomena presented on maps, relative blackness, complexity, similarity between map patterns, correlation rate (positive or negative), degree of association (certain levels of cerrelation may be more difficult to judge), user's experience in map reading. Further, space units can gain relative significance due to their size, shape and location (central, peripheral), belonging to a class (extreme or middle) and geographical knowledge of the map reader. The choice of class selection method can influence the map reception by affecting some of the above factors. Application of equal area method, for example, makes it possible to obtain similar blackness on all maps, and therefore eliminates this factor's influence on the judgement of similarity. It is more difficult to limit the influence of other factors - so far there are no other such solutions. Attempts to reach comparability of choropleth maps meet many obstacles. One should then consider more efficient ways of presenting relations between phenomena. Two-variable choropleth map can be such a way, although it should be noted that it is also much more difficult to interpret. Therefore it seems necessary to conduct further research on maps, which would facilitate correct evaluation of relations between presented phenomena.