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Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism
Fallen leaves are the main issues for train operations in the autumn season due to their low friction coefficient (COF), leading to signals being passed dangerously and amended timetables. The main aim of this study was to elucidate the mechanism of low friction due to black leaf films, which are of...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9086331/ https://www.ncbi.nlm.nih.gov/pubmed/35547698 http://dx.doi.org/10.1039/c8ra06080k |
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author | Ishizaka, Kei Lewis, Stephen R. Hammond, Deborah Lewis, Roger |
author_facet | Ishizaka, Kei Lewis, Stephen R. Hammond, Deborah Lewis, Roger |
author_sort | Ishizaka, Kei |
collection | PubMed |
description | Fallen leaves are the main issues for train operations in the autumn season due to their low friction coefficient (COF), leading to signals being passed dangerously and amended timetables. The main aim of this study was to elucidate the mechanism of low friction due to black leaf films, which are often seen on leaf-contaminated rails. A black material was successfully synthesised in the laboratory with water extracts from sycamore leaves and a plate of R260 rail steel. The black powder made from the extracts of brown leaves (BBP) was identified as the key material of low friction by the pin-on-flat tribological test, giving a COF between 0.08 and 0.14, which was lower than the COF of commercial engine oil (approximately 0.14). X-Ray fluorescence showed that the black material was a mixture of iron and leaf-organics. Laser Raman spectroscopy revealed that graphite-like carbon was likely to be formed on iron oxides. Fourier transform infrared spectroscopy showed that the formation of iron carboxylate was likely in bulk, which possibly transformed into iron oxides on the surface. Moreover, X-ray photoelectron spectroscopy detected a relatively high concentration of phosphates only in BBP. Hence, the low friction is presumably due to graphitic carbon, iron oxides and phosphate compounds in the black leaf films, as well as mechanical separation effects of bulk leaves. This black material could be a product of the Maillard reaction or reaction between iron and organic acids, such as tannic acids. |
format | Online Article Text |
id | pubmed-9086331 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-90863312022-05-10 Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism Ishizaka, Kei Lewis, Stephen R. Hammond, Deborah Lewis, Roger RSC Adv Chemistry Fallen leaves are the main issues for train operations in the autumn season due to their low friction coefficient (COF), leading to signals being passed dangerously and amended timetables. The main aim of this study was to elucidate the mechanism of low friction due to black leaf films, which are often seen on leaf-contaminated rails. A black material was successfully synthesised in the laboratory with water extracts from sycamore leaves and a plate of R260 rail steel. The black powder made from the extracts of brown leaves (BBP) was identified as the key material of low friction by the pin-on-flat tribological test, giving a COF between 0.08 and 0.14, which was lower than the COF of commercial engine oil (approximately 0.14). X-Ray fluorescence showed that the black material was a mixture of iron and leaf-organics. Laser Raman spectroscopy revealed that graphite-like carbon was likely to be formed on iron oxides. Fourier transform infrared spectroscopy showed that the formation of iron carboxylate was likely in bulk, which possibly transformed into iron oxides on the surface. Moreover, X-ray photoelectron spectroscopy detected a relatively high concentration of phosphates only in BBP. Hence, the low friction is presumably due to graphitic carbon, iron oxides and phosphate compounds in the black leaf films, as well as mechanical separation effects of bulk leaves. This black material could be a product of the Maillard reaction or reaction between iron and organic acids, such as tannic acids. The Royal Society of Chemistry 2018-09-19 /pmc/articles/PMC9086331/ /pubmed/35547698 http://dx.doi.org/10.1039/c8ra06080k Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/ |
spellingShingle | Chemistry Ishizaka, Kei Lewis, Stephen R. Hammond, Deborah Lewis, Roger Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism |
title | Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism |
title_full | Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism |
title_fullStr | Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism |
title_full_unstemmed | Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism |
title_short | Chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism |
title_sort | chemistry of black leaf films synthesised using rail steels and their influence on the low friction mechanism |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9086331/ https://www.ncbi.nlm.nih.gov/pubmed/35547698 http://dx.doi.org/10.1039/c8ra06080k |
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