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Analysis of friction and wear processes in an innovative spine stabilization system. Part 1. A study of static and kinetic friction of a metal rod-polymer cord friction joint

Brończyk Anna

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 1

118--130

EN

This analysis is the first part of research that aims to develop a model of the tribological wear of PE-UHMW cord – biometal rod combination. This type of sliding joint is applied in spine stabilization systems that enable the treatment of early-onset idiopathic scoliosis. Methods: The friction tests included force measurements, followed by the determination of static and kinetic friction coefficients as a function of the number of the performed movement cycles, and static friction coefficient with regards to the string tension force FN in the range of 50–300 N. Additionally, the surface roughness and microscopic observations of the metal rods were made. The friction measurements were carried out at a stabilized temperature T = 38 °C in the presence of distilled water and acidic sodium lactate. Results: The measurements confirmed the impact of both the number of completed movement cycles and the value of the force loaded on the cord on the static friction coefficient. Similar values of kinetic friction force occur for the pairs with the titanium alloys rods, as well as for the pairs with the steel and CoCr rod. The type of lubricant affected the obtained measurement results unevenly: (Ti6Al4V and Ti6Al7Nb – slight impact, steel 316L and CoCrMo – large impact). During microscopic observations, numerous wear products, were visible, including harder than the base material large conglomerates. Conclusions: Susceptibility of polymer fibres results in its increased resistance to wear, but it can be also combined with an increase in wear of the surface of the metal rod.

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Surface modification of polypropylene nonwoven with composite metallic layers

Reszka K., Dobruchowska E., Koprowska J., Wiśniewski B.

Journal of KONES

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2012

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Vol. 19, No. 4

539-547

EN

Polymer fibres have the great potential for application due to their large surface area relative to volume, incomparably large length relative to the cross-section, high strength and ease of forming the nonwovens in thermal processing. Due to the specific properties of textiles, they are applied, among others in the manufacture of filters, sensors, biomedical devices and protective clothing. This study was aimed to evaluate the surface morphology of polypropylene nonwoven modified with metallic layers CuSn, CuZnNi, NiCuFe, deposited by the magnetron sputtering technique. There was also carried out a qualitative and quantitative analysis of deposited thin layers and their compositions were compared with compositions of targets used for magnetrons. The surface morphology was tested using the metallographic optical microscope with a CF160 optical system and the scanning electron microscope adapted to work in an environmental mode. A study of composition was based on a microanalysis using the energy dispersive X-ray radiation deriving from the excited atoms (EDS).

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Comparative Analysis of the Properties of Active Carbon Fibres Obtained from Different Precursors

Babeł K., Krucińska I., Cisło R., Koszewska M.

Fibres & Textiles in Eastern Europe

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2006

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Vol. 14, no. 4 (58)

79--86

EN

This paper presents the changes to some properties and structural features of four types of polymer fibres and the nonwovens obtained from them during fibre pyrolysis and the following steam activation at a temperature of 850 °C of the carbon nonwovens obtained. The changes in tenacity of the precursor, the carbon, and the active carbon nonwovens as the result of thermal and oxidation processing were tested, among others. We stated that the loss of tenacity mainly takes place during the pyrolysis and the accompanied radical reconstruction of the fibre structure. The activation process, although connected with a further great loss of mass, causes relative significantly small changes in the tenacity of the active carbon nonwovens obtained from viscose and phenolic resin-based fibres, whereas the mechanical properties of active carbon nonwovens obtained from polyacrylonitrile fibres as a precursor decrease even further considerably.

PL

W artykule omówiono zmiany pewnych właściwości i cech strukturalnych czterech typów włókien i włóknin z nich otrzymanych poprzez proces pirolizy włókien a następnie proces aktywacji parą wodną w temperaturze 850 oC. Oceniano między innymi zmiany wytrzymałości prekursora i aktywowanych włóknin węglowych otrzymanych w wyniku obróbki cieplnej i utleniania. Stwierdzono, że utrata wytrzymałości ma miejsce głównie podczas procesu pirolizy i towarzyszy przebudowie struktury włókna. Proces aktywacji, mimo że połączony z późniejszym dużym spadkiem masy, powoduje względnie małe zmiany wytrzymałości włóknin węglowych otrzymanych z włókien wiskozowych i włókien bazujących na żywicach fenolowych, podczas gdy właściwości mechaniczne włóknin węglowych otrzymanych z włókien, których prekursorem był poliakrylonitryl obniżają się znacznie.

4

Experiments and modelling of electrospinning process

Kowalewski T., Błoński S., Barral S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2005

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Vol. 53, nr 4

385-394

EN

Very thin liquid jets can be obtained using electric field, whereas an electrically-driven bending instability occurs that enormously increases the jet path and effectively leads to its thinning by very large ratios, enabling the production of nanometre size fibres. This mechanism, although it was discovered almost one century ago, is not yet fully understood. In the following study, experimental data are collected, with the dual goal of characterizing the electro-spinning of different liquids and evaluating the pertinence of a theoretical model.

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Modelowanie transportu obrazu modyfikowanymi włóknami polimerowymi

Wójcik M.

Bio-Algorithms and Med-Systems

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2005

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Vol. 1, no. 1/2

273--276

PL

W artykule przedstawiono próbę aplikacji teorii informacji dla procesu jej przetwarzania i przekazu na drodze oko-mózg i zaproponowano pewne rozwiązanie równań Maxwella w postaci równań hiperbolicznych jako podejście do rozpoznania procesu przekazu obrazu we włóknie nerwowym. Otrzymane rozwiązanie pokazuje, w jaki sposób żywy organizm może przesyłać obraz od receptora (oko) poprzez włókno nerwowe do mózgu. Odpowiednio zmodyfikowane włókno polimerowe po zadaniu na wejściu sterowalnym sygnałem elektrycznym powinno dać odpowiedź w postaci prądu elektrycznego o zmienionej częstotliwości i pola magnetycznego odpowiadającego natężeniu prądu. Ten model daje szansę na lepsze poznanie i zrozumienie mechanizmu przesyłania informacji jako historii zewnętrznego świata w procesie komunikowania się organizmów żywych.

EN

A certain solution of Maxwell's equations using hyperbolic formula was proposed as an approach to the recognition of the process of image transfer from a receptor (eye) trough neurone fibres into the brain; a trial application of an information theory for the image transfer is presented in the paper. Solution of the equation explains the way in which human body transfers an image from the eye into the brain. Suitably modified polymer fibres after inputting controlled electrical signal can give an answer as an electrical current with changed frequency and a magnetic field corresponding with an intensity of the current. This model gives an opportunity of better recognition and understanding of the mechanism of image transfer as an external history at the communication process between living organisms.