7 pages, 6 figures, 1 tableThere is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35nm and 85nm were obtained from SMPS/APS measurements over the range 6-20,000nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z>100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment. © 2014 Elsevier Ltd.Peer Reviewe

This paper researches on a cyber-physical energy-saving control framework for a plug-in hybrid aircraft-towing tractor, in which, an online optimization methodology named the Online Swarm Intelligent Programming (OSIP) is proposed. The new methodology obtains real-time optimal control signals from the V2X network and the widely-used Charge Depleting/Charge Sustaining (CD/CS) strategy is upgraded to a more adaptive and intelligent level. The energy-flow of the hybrid aircraft-towing tractor with connectivity is firstly analysed and modelled for OSIP. The optimal control problem is then formulated as an online integer optimization and the OSIP algorithm based on Chaos-enhanced Accelerated Swarm Optimization (CAPSO) is developed to minimize the powertrain power loss in real-time. Finally, the advantages of the new energy management system are demonstrated and evaluated by hardware-in-the-loop testing. The results show that up to 17% fuel and 13% total energy loss can be saved via the proposed cyber-physical control.

Future sustainability of road transportation will require substantial improvement in the efficient use of energy by road vehicles. As new technologies being deployed reduce total vehicle energy consumption, the contribution of tyre rolling resistance to total energy consumption continues to increase. For this reason tyre rolling-resistance is starting to drive the focus of many tyre developments nowadays. This is because the rolling-resistance can be responsible for 20–30% of the total vehicle fuel consumption. Thus, lowering the rolling-resistance would help to reduce the fuel consumption (i.e. CO₂, NOx and hydrocarbon emissions) and hence improve the environment greatly given the large number of vehicles used globally. It is found that the primary source of the rolling-resistance is the tyre deformational behaviour (i.e. hysteresis damping) which can account for 80–95% of the total rolling-resistance. This paper reviews the state of the art in tyre design, research and development for lower rolling-resistance, with focus on the primary source for the rolling-resistance (i.e. mechanical hysteresis damping), from three perspectives: the structural lay-up; the dimensional features; and the materials compound(s) of the tyre.