Tire wear particles in the aquatic environment - A review on generation, analysis, occurrence, fate and effects.

The engine, which uses both conventional diesel fuel and LPG fuel, is referred to as ‘LPG–diesel dual fuel engines’. LPG dual fuel engines are modified diesel engines which use primary fuel as LPG and secondary fuel as diesel. LPG dual fuel engines have a good thermal efficiency at high output but the performance is less during part load conditions due to the poor utilization of charges. This problem can be overcome by varying factors such as pilot fuel quantity, injection timing, composition of the gaseous fuel and intake charge conditions, for improving the performance, combustion and emissions of dual fuel engines. This article reviews about the research work done by the researchers in order to improve the performance, combustion and emission parameters of a LPG–diesel dual fuel engines. From the studies it is shown that the use of LPG in diesel engine is one of the capable methods to reduce the PM and NOx emissions but at same time at part load condition there is a drop in efficiency and power output with respect to diesel operation.

LPG diesel dual fuel engine – A critical review

Effect of exhaust gas recirculation on advanced diesel combustion and alternate fuels - A review

The effects of discharge radiofrequency (RF) power and film thickness were studied on the characteristics of Ca5(PO4)3OH (hydroxyapatite) thin films fabricated by RF magnetron sputtering. The structure and chemical composition were investigated with alpha-step (thickness), scanning electron microscopy (SEM), X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), and infrared absorption spectrometry (FTIR). The films were analyzed as-sputtered and after annealing at 550 degrees C under argon flow. SEM showed that the film surfaces had no cracks or other defects. X-ray diffraction showed that the deposited films were amorphous with low-discharge RF power, and crystalline with high-discharge RF power. After annealing, all the films had the same crystalline structure as apatite. However, the RBS measurements revealed that all films had a higher calcium-phosphate ratio than standard synthetic hydroxyapatite. Furthermore, statistical testing of the RBS data revealed the existence of only a weak correlation between the Ca/P ratio and the discharge power level. Although all sputtered films showed phosphate bonds in the infrared spectrum, only after annealing did the OH bonds of hydroxyapatite become visible.

Influence of discharge power level on the properties of hydroxyapatite films deposited on Ti6A14V with RF magnetron sputtering

Thin calcium phosphate coatings with a thickness of 0.09 to 2.7 µm were prepared by radio-frequency magnetron sputtering deposition on NiTi and Ti substrates at a substrate temperature of 500 °C in argon atmosphere. Scanning electron microscopy (SEM) showed that the surface structure is uniform and dense without visible defects (pores and microcracks). Rutherford backscattering spectroscopy (RBS) and energy-dispersive X-ray spectroscopy (EDX) confirmed that the coating contains calcium, phosphorus, and oxygen with a uniform composition. Crystallographically, the coating consists of crystalline hydroxyapatite which is also supported by infrared spectroscopy. The mechanical characteristics of the coating were measured by nanoindentation (Vickers indenter), giving a nanohardness of 10 GPa and a Young's modulus of 110 GPa. The strength of adhesion of the calcium phosphate coating to the metallic substrates depended on the coating's thickness and decreased for a thickness larger than 1.6 µm. No difference was observed between NiTi and Ti substrates.

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The preparation of calcium phosphate coatings on titanium and nickel–titanium by rf-magnetron-sputtered deposition: Composition, structure and micromechanical properties

A large fraction of urban PM10 concentrations is due to non-exhaust traffic emissions, including road dust, particles from tire/road interface, and brake lining particles. Although potential health and environmental impacts associated with tire wear debris have increased, few environmentally and biologically relevant studies of actual tire wear debris have been conducted. Tire wear particles (TWP) are released from the tire tread as a result of the interaction between the tire and the pavement. Roadway particles (RP), meanwhile, are particles on roads composed of a mixture of elements from tires, pavement, fuels, brakes, environmental dust, and the atmosphere. The main objective of the present study is to identify the contribution of tires to the generation of RP and to assess the potential environmental and health impacts of this contribution. First, a mobile measurement system was constructed and used to measure the RP on asphalt roads according to vehicle speed. The equipment of the mobile system provides PM10 concentration by DustTrak DRX, and mass and number size distribution of fine and ultrafine particles by a fast mobility particle sizer (FMPS) and an aerosol particle sizer (APS). The dependence of RP mass and particle number concentration on vehicle speed was observed. It was also found that many particles were generated by rapid deceleration of the vehicle.

Properties of roadway particles from interaction between the tire and road pavement

Emission reduction potential in a light-duty diesel engine fueled by JP-8

Recent studies on dual-fuel combustion in compression-ignition (CI) engines, also known as diesel engines, fall into two categories. In the first category are studies focused on the addition of small amounts of gaseous fuel to CI engines. In these studies, gaseous fuel is regarded as a secondary fuel and diesel fuel is regarded as the main fuel for combustion. The objectives of these studies typically involve reducing particulate matter (PM) emissions by using gaseous fuel as a partial substitution for diesel fuel. However, the addition of gaseous fuel raises the combustion temperature, which increases emissions of nitrogen oxides (NOx). In the second category are studies focused on reactivity-controlled compression-ignition (RCCI) combustion. RCCI combustion can be implemented by early diesel injection with a large amount of low-reactivity fuel such as gasoline or gaseous fuel. Although RCCI combustion promises lower NOx and PM emissions and higher thermal efficiency than conventional diesel combustion, it requires a higher intake pressure (usually more than 1.7 bars) to maintain a lean fuel mixture. Therefore, in this study, practical applications of dual-fuel combustion with a low air-fuel ratio (AFR), which implies a low intake pressure, were systemically evaluated using propane in a diesel engine. The characteristics of dualfuel combustion for high and low AFRs were first evaluated. The proportion of propane used for four different operating conditions was then increased to decrease emissions and to identify the optimal condition for dual-fuel combustion. Although the four operating conditions differ, the AFR was maintained at 20 (ϕ approximately equal to 0.72) and the 50% mass fraction burned (MFB 50) was also fixed. The results show that dual-fuel combustion can reduce NOx and PM emissions in comparison to conventional diesel combustion.

Reduction of emissions with propane addition to a diesel engine

The effects of argon pressure and the solute element on compositional changes have been studied in binary Co-early transition metal (ETM) thin films fabricated by r.f. magnetron sputtering using the composite target mode. The solute concentration of the deposited film increases linearly with the area fraction of solute element of target and with the logarithm of argon pressure in the range 0.5–10 m torr. The compositional changes are discussed by considering not only the sputtering yield but also the argon pressure, which is related to the collision effect, and the difference in atomic weights between Co and ETM elements.

Jungyeon Lee

Papers

Properties of roadway particles from interaction between the tire and road pavement

Emission reduction potential in a light-duty diesel engine fueled by JP-8

Reduction of emissions with propane addition to a diesel engine

Influence of argon pressure on the composition of Co-early transition metal films fabricated by r.f. magnetron sputtering in the composite target mode

A Study of Emissions Reduction through Dual-Fuel Combustion with Propane in a Compression Ignition Engine