Wyniki 1-2 spośród 2 dla zapytania: authorDesc:"Andrzej Krzyszkowski"

Co dalej z kolejami dużych prędkości? DOI:


  W pracy przedstawiono problemy trzech grup kolei o dużych prędkościach; koleje konwencjonalne (układ pojazd - tor - szyna S-60): koleje o podwyższonej prędkości (prędkość pociągów pasażerskich do 250 km/h oraz prędkość pociągów towarowych do 120 km/h), koleje o dużej prędkości do 350 km/h (tylko pociągi pasażerskie), koleje niekonwencjonalne Hyperloop - prędkość do 1500 km/h. Omówiono bariery wprowadzenia kolei konwencjonalnych na terenie Polski. Pokazano międzynarodowe koncepcje, w których powinna uczestniczyć Polska; wschód-zachód, północ-południe; stan realizacji tych połączeń. Przedstawiono zasady funkcjonowania kolei niekonwencjonalnych typu Hyperloop. Słowa kluczowe: koleje dużych prędkości, koleje konwencjonalne, Hyperloop Summary: The paper presents the problems of three groups of high-speed rail; conventional railways (the vehicle - track - rail system S-60): railways upgraded for the high speed, the passenger trains speed up to 250 km/h and freight trains up to 120 km/h; high-speed rail up to 350 km/h (passenger trains only), the unconventional rail - Hyperloop - speed up to 1500 km h. The barriers of the introduction of conventional rail in Poland were discussed. The international east - west and north - south concepts in which Poland should participate and their current status of implementation were shown. The operation principles of the unconventional type of railway as Hyperloop were presented. Keywords: high - speed rail, conventional railways, Hyperloop.Transport kolejowy o podwyższonych prędkościach staje się powszechny w Europie i w innych częściach świata. Istnieje kilka koncepcji realizacji kolei o podwyższonej prędkości (200÷300 km/h). Koncepcje te zakładają transport ludzi i ładunków w dwóch kierunkach: wschód-zachód i północ-południe. Obydwie koncepcje zakładają, że linie te będą przechodzić przez Polskę. Realizacja tych koncepcji jest aktualnie obarczona wieloma barierami, które uniemożliwiają wprowadzenie na ter[...]

The influence of the structure direction on diamond-like carbon coatings tribological properties DOI:10.15199/28.2017.5.6


  1. INTRODUCTION Diamond-like carbon coatings provides an excellent means of combining the low friction properties and high wear resistance of tribological systems and have been successfully used in a wide range of maintenance technique [1÷3]. DLC coatings have unique properties such as high hardness, good thermal and electrical conductivity, chemical stability and biocompatibility. Extremely diverse properties of DLC coatings result from the different types of bonding between carbon atoms, including sp3, sp2 and sp1 hybridizations [2, 4]. Properties of DLC coatings can be further modified by the addition of dopants, i.e. elements such as nonmetals (H, Si, F, N, O, P, B) and metals (Ti, Ta, Cr, Mo, W, Ru, Fe, Co, Ni, Al, Cu, Nb, V and Ag) or their combinations, improves the tribological properties of the coatings without changing their amorphous character [5]. The mechanism by which the DLC coating contributes to a decrease in the coefficient of friction is that there is a transfer of material from the coating to the upper specimen and that a lubricating film forms on the DLC surface [5÷7]. Diamond-like carbon coatings are widely used in many industries. In the automotive industry are used as protective coatings on parts of the vehicle. In the computer industry they are used as carriers magnetic disks. They are also used in the aerospace, and are applied to the elements of biomaterials in medicine. DLC coatings are ideal for the protection of friction with heavy loads. In this study, DLC coatings were analyzed with regard to their morphology, topography, and especially their tribological properties under dry friction and lubrication conditions. The preparation of the substrate involved polishing steel surfaces in order to obtain established directionality of the structure prior to depositing the DLC coatings. It is common knowledge that the geometrical structure is decisive for the tribological properties. The wear and friction[...]

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