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The tiny contact zone (approximately 1 cm2) where steel wheel meets steel rail is fundamental to rail transport. This work is a comprehensive presentation of recent research in wheel-rail contact tribology. It stresses that, unlike gears or rolling bearings which are sealed contacts with reduced exposure to the surrounding environment, a wheel-rail contact is an open system that is exposed to dirt
The tribology of an open system at temperatures ranging between 3 °C and -35 °C, with and without snow, was investigated using a pin-on-disc tribometer mounted in a temperature-controlled environmental chamber. The relationship between the microstructure and ductility of the materials and the tribology at the contacting surfaces was investigated. The study shows that during continuous sliding, pre
The purpose of this work-package within the Quiet-track, FP7, is to develop a noise related track maintenance tool, in the form of an on-board measurement system. As a first step, lab scale tests using a pin-on-disc tribometer were used in order to distinguish how noise changes when the wear mechanism in a sliding contact shifts from normal wear to severe and catastrophic wear. Once the potential
This experiment investigated the effect of tin in an amount up to 0·121 wt-% on the microstructure and mechanical properties of compacted graphite iron. Graphite and matrix evolution was emphasised with the help of scanning electron microscopy. The results indicate that Sn in experimental range reduces graphite size. Pearlite quantity would increase with the increasing Sn and reaches over 95% when
Ni-based composite coatings containing varied contents of tungsten carbides on low carbon steel were fabricated. Effects of sintering temperature and tungsten carbides contents on the surface, interface, microstructure and wear resistance of the coatings were investigated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Vickers microhardness tester, bulk
Noise from the wheel-rail interface is a troublesome side effect when railway vehicles negotiate rail curves. In this laboratory study, two pin-on-disc tribometers were used to simulate the pure sliding process in the wheel-rail contact. The purpose was to investigate the relationships between surface topographies, tribological aspects and the emitted noise. Five different surface topographies man
Fe-based composite coatings were fabricated on Q235 steel substrate by plasma cladding. B4C particles were injected at the center and edge of the melting pool as strengthening phase. Scanning electron microscopy and pin-on-disc tribometer were applied to study the microstructure and wear resistance of the coatings. The results showed that the central injected B4C particles dissolved during plasma
Railways operate in an open environment where temperature, humidity, and the oxidation conditions are subjected to change. An experimental investigation used a pin-on-disc machine to examine the influence of environmental conditions and iron oxides on the wear performance of the wheel-rail contact. The wear mechanisms were analyzed using scanning electron microscopy and found to be highly dependen
The coefficient of friction between railway wheels and rails is crucial to the railway adhesion, further greatly affecting railway operation and maintenance. Since the wheel-rail system is an open system, the coefficient of friction is significantly influenced not only by various types of contaminants but also by environmental conditions. This paper conducted a set of pin-on-disc tests measuring t
Aluminum matrix fly ash (AMFA) cenosphere composites were fabricated using the stir casting technique. The used type of fly ash cenosphere, which accounted for over 60% in all fly ash particles, was in narrow and small size (2-30 μm). During synthesis, effects of several key technological parameters on microstructure and properties were investigated using orthogonal experimental design. The optima
The effect of aluminum on microstructure and properties of martensitic wear-resistant and heat-resistant steels was investigated. The results indicate that as-cast microstructure of the specimens is composed of ferrite, pearlite and carbides. After quenching at 1,000 C and tempering at 600 C, the microstructure of the specimens consists of tempered sorbite and Fe-Cr-Al intermetallic compounds whic
Effect of aluminium on microstructure and properties of austenitic heat resistant steel was investigated. The results showed that Al addition led to formation of spheroidal and dispersed Ni3Al. After solution treatment, Ni3Al particles experienced a significant refinement from 1.5 μm to nanoscale (∼80 nm). Matrix transformed from austenite to ferrite when addition of Al was >4.72%. Oxidation resis
High-ductility ductile iron was alloyed with 0-1.8wt% Ni in this paper. The low-temperature impact toughness test and corrosion test of simulated seawater static whole-soaking were conducted to research the effect of nickel on the low-temperature impact toughness and corrosion resistance of high-ductility ductile iron. The results show that with nickel increasing, the impact toughness under low te
In this study, effect of tungsten on microstructure and properties of high chromium cast iron was investigated. The experimental results indicated that tungsten distributed uniformly in the matrix and carbides. W carbides are composed of WC1-x, W6C2.54 and CW3 and W2C. With the increase of tungsten content, bulk hardness and matrix microhardness both increased gradually and reached the peak at 62.
Autonomous vehicle is being developed for widespread deployment. Its reliability and safety are critically dependent on advanced wireless technologies, e.g., vehicle-to-everything (V2X) communication. The frontend of a V2X system needs an antenna module that enables the vehicle to reliably connect to all other networks. Designing V2X antenna is challenging due to the complex in-vehicle environment
Experimental governance is increasingly being implemented in cities around the world through laboratories, testbeds, plat- forms, and innovation districts to address a wide range of complex sustainability challenges. Experiments often involve public-private partnerships and triple helix collaborations with the municipality as a key stakeholder. This stretches the responsibilities of local authorit
Municipal leaders around the world are demonstrating significant interest in urban greening to realize a range of socioecological benefits. The urban greening toolkit often includes street trees, an essential component of urban design informed by historic legacies of both human and environmental factors. To date, there has been little comparative analysis of street tree density and distribution ac
Techno-politics is alive and well in cities of the twenty-first century, most prominently with the rise of smart cities and the digitalization of urban life but also in the myriad debates about climate and environment, social cohesion and democracy, and economic prosperity and well-being. This commentary uses the special issue on ‘Urban Techno- Politics’ as inspiration to reflect on three emerging
Conventional pastureland management has brought Southern Brazilian dairy farms to a financial and environmental crisis. In this context, the management-intensive grazing system (MIG) emerges as a viable alternative to conventional pastureland management. This study aims to analyze the Social-Ecological System (SES) transformation process of the dairy system in Santa Rosa de Lima, Southern Brazil,
Today’s smart city agendas are the latest iteration of urban sociotechnical innovation. Their aim is to use information and communication technologies (ICT) to improve the economic and environmental performance of cities while hopefully providing a better quality of life for residents. Urban planners have a long-standing tradition of aligning technological in- novation with the built environment a
