Showing papers by "Branka Miljevic published in 2013"
TL;DR: The oxidative potential of the PM, measured through the ROS content, shows a much higher correlation with the oxygenated organic fraction as measured by the c-ToF AMS, highlighting the importance of knowing the surface chemistry of particles for assessing their health impacts.
Abstract: Generally, the magnitude of pollutant emissions from diesel engines running on biodiesel fuel is ultimately coupled to the structure of respective molecules that constitutes the fuel. Previous studies demonstrated the relationship between organic fraction of PM and its oxidative potential. Herein, emissions from a diesel engine running on different biofuels were analysed in more detail to explore the role different organic fractions play in the measured oxidative potential. In this work, a more detailed chemical analysis of biofuel PM was undertaken using a compact Time of Flight Aerosol Mass Spectrometer (c-ToF AMS). This enabled a better identification of the different organic fractions that contribute to the overall measured oxidative potentials. The concentration of reactive oxygen species (ROS) was measured using a profluorescent nitroxide molecular probe 9-(1,1,3,3-tetramethylisoindolin-2-yloxyl-5-ethynyl)-10-(phenylethynyl)anthracene (BPEAnit). Therefore the oxidative potential of the PM, measured through the ROS content, although proportional to the total organic content in certain cases shows a much higher correlation with the oxygenated organic fraction as measured by the c-ToF AMS. This highlights the importance of knowing the surface chemistry of particles for assessing their health impacts. It also sheds light onto new aspects of particulate emissions that should be taken into account when establishing relevant metrics for assessing health implications of replacing diesel with alternative fuels.
53 citations
TL;DR: Results show that moderate ethanol substitutions at moderate load, high percentage soy blends, and alternative fuels provide an efficiency and emissions profile that yields the most "preferred" solutions to this multicriteria engine design problem.
Abstract: Compression ignition (CI) engine design is subject to many constraints which presents a multi-criteria optimisation problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient, but must also deliver low gaseous, particulate and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming are minimised. Consequently, this study undertakes a multi-criteria analysis which seeks to identify alternative fuels, injection technologies and combustion strategies that could potentially satisfy these CI engine design constraints. Three datasets are analysed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of 1): an ethanol fumigation system, 2): alternative fuels (20 % biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and 3): various biodiesel fuels made from 3 feedstocks (i.e. soy, tallow, and canola) tested at several blend percentages (20-100 %) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20 % by energy) at moderate load, high percentage soy blends (60-100 %), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most “preferred” solutions to this multi-criteria engine design problem. Further research is, however, required to reduce Reactive Oxygen Species (ROS) emissions with alternative fuels, and to deliver technologies that do not significantly reduce the median diameter of particle emissions.
12 citations
Journal Article•
6 citations
01 Jan 2013
TL;DR: The issue of particle emissions from diesel engines is still a matter of concern due its deleterious effects both on human health and the environment (Ristovski et al., 2012) as mentioned in this paper.
Abstract: The issue of particle emissions from diesel engines is
still a matter of concern due its deleterious effects both
on human health and environment(Ristovski et al.,
2012). Recently, International Agency for Research on
Cancer (IARC) inclusion of diesel engine exhaust
particles as carcinogenic to human health added a new
margin on it. Apart from the use of after treatment
technology, biodiesel is also considered as potential way
to reduce particle emission alongside with other
emissions(Xue, Grift, & Hansen, 2011). Global biodiesel
production is still reasonably small compared to its
counterpart fossil diesel, but even this small amount
comes from a wide variety of feed stocks. Contrary to
fossil diesel, the important physicochemical properties of
biodiesel vary among different feed stocks(Hoekman,
Broch, Robbins, Ceniceros, & Natarajan, 2012).
1 citations
01 Jan 2013
TL;DR: In this paper, a multi-criteria analysis was conducted to identify alternative fuels, injection technologies and combustion strategies that could potentially satisfy these compression ignition (CI) engine design constraints, in particular, the modern CI engine must not only be efficient, but must also deliver low gaseous, particulate and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming are minimised.
Abstract: Compression ignition (CI) engine design is subject to many constraints which presents a multi-criteria optimisation problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient, but must also deliver low gaseous, particulate and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming are minimised. Consequently, this study undertakes a multi-criteria analysis which seeks to identify alternative fuels, injection technologies and combustion strategies that could potentially satisfy these CI engine design constraints. Three datasets are analysed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of 1): an ethanol fumigation system, 2): alternative fuels (20 % biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and 3): various biodiesel fuels made from 3 feedstocks (i.e. soy, tallow, and canola) tested at several blend percentages (20-100 %) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20 % by energy) at moderate load, high percentage soy blends (60-100 %), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most “preferred” solutions to this multi-criteria engine design problem. Further research is, however, required to reduce Reactive Oxygen Species (ROS) emissions with alternative fuels, and to deliver technologies that do not significantly reduce the median diameter of particle emissions.
1 citations