Senior Lecturer

ATMOSPHERIC CHEMISTRY

Species in trace quantities in the atmosphere play significant roles in many processes that directly and indirectly affect the quality of our life.  We are interested in understanding the sources, reactions and effects that these species have.

The described projects are indicative of the work carried out in the Atmospheric Chemistry group.  Research programs are negotiable and areas of interest to potential students will be accommodated if they fall within the general theme of the group’s activities.

Trace Gases and Volatile Organic Compounds

Identifying and quantifying the sources of volatile organic compounds (VOC’s) is important as these compounds are involved in complex chemical and physical transformations that result in effects such as smog formation, changes in the oxidative capacity of the atmosphere and aerosol formation.  Large volumes of VOC’s are emitted from plants (biogenic VOC’s) and from human activities (anthropogenic VOC’s), such as fossil fuel and biomass combustion, evaporation of solvents and fuels and production processes.  Much effort has been put into reducing emissions of anthropogenic VOC’s, yet if the quantity of biogenic VOC’s is significant, then this effort may be misplaced.

VOC’s and other trace species (such as NO, NO₂ and CO) are contributors to poor indoor air quality.  Increasing urbanisation results in an increase in the occupation of well-sealed buildings using recirculated air for climate control, which may lead to a decrease in indoor air quality.  This is a growing concern throughout the world.  Identification of sources of VOC’s and other trace species is a central issue in environmental management.

We have a range of projects concerned with identifying and quantifying VOC’s and their sources.  The techniques incorporate Solid Phase Microextraction with GC and GC/MS analysis, cavity ring-down spectroscopy and Fourier Transform Infrared spectroscopy.

Synthesis and Characterisation of Important Peroxyl Nitrate Compounds

The PAN family of compounds play a very important role in atmospheric chemistry because they act as reservoirs of reactive nitrogen (NO_X).  While the archetypal compound, peroxyacetyl nitrate, (CH₃C(O)OONO₂) is relatively well characterised, there is little information available concerning the compounds in the family based on this structure.  Good quality infrared spectra are needed for use in identifying and quantifying these species in smog chamber experiments.  A number of compounds have been identified from modelling studies as important targets for synthesis and characterisation.  In this project, we will synthesize as many of these compounds as possible and obtain their infrared spectra.  Characterisation of the product mixture will be achieved through infrared spectroscopy and GC-MS investigations.  Vibrational analysis using computer-based modelling (Gaussian) will be used to aid in spectral identification.  Synthesis will be undertaking using photolytic gas phase reactions, and liquid phase reactions if appropriate to obtain pure samples.  There is the possibility of conducting atmospheric simulation experiments using the CSIRO Energy Technology smog chamber facilities.

Emissions of Greenhouse Gases from Vehicles

The substitution of compressed natural gas (CNG) for diesel fuel in heavy-duty vehicles has potential greenhouse gas benefits due to an expected reduction in CO₂ emissions.   However, even if CO₂ emissions are reduced, the nett global warming potential may be offset by increased emissions of gases with greater global warming potentials (e.g. N₂O and CH₄).  The present work was initially commissioned by the Australian Greenhouse Office as a pilot study to determine N₂O emissions from dual-fuel trucks operated back-to-back on diesel and then in CNG/diesel mode.  Analyses were carried out by using an analyser specific to N₂O (continuous, on-site) and off-line by FTIR spectroscopy of filtered bag samples.  The FTIR spectra are also processed to obtain CO and CH₄ concentrations.

Emissions of Organic Compounds in Natural Product Chemistry

Vegetation emits significant quantities of Volatile Organic Compounds.  These emissions may be correlated with internal chemistry of the plants, and give clues on such things as the presence of useful compounds, stage of plant development and the maturation state of fruit.  The relatively new technique of Solid-Phase Microextraction (SPME) offers a route to convenient in situ sampling.  SPME combines in one-step sampling and preconcentration, prior to GC or GC-MS analysis.  Our research activity aims at developing methods of in situ SPME-GC analysis, and to develop a database of VOC emissions from Australian native vegetation.

Biosphere-Atmosphere Interactions Using Isotopic Ratios of Trace Gas Species

Chemical and biological processes in nature, such as respiration, photosynthesis and atmospheric chemical reactions, often discriminate between different isotopes in the chemical species concerned.  Careful analysis of the isotopic composition of atmospheric trace gases can thus provide very valuable information on the sources and sinks of the gases concerned because each natural process leaves its isotopic "signature" in the gases it produces. For example, the D/H ratio in atmospheric water vapour provides a valuable tracer for exchange and transport processes.  Low resolution FTIR spectrometry is a valuable technique for determining this ratio, as in situ field measurements of the D/H ratio can be made with a precision of the order of 1‰.

Photo-oxidation of VOC’s from Australian Vegetation

Oxidation of compounds emitted by plants occurs through a series of cyclic chain reactions, initiated principally by the hydroxyl radical, OH.  Hydroxyl radicals are produced photolytically, hence the process is generally one of photo-oxidation. Products from this photo-oxidation are involved in a number of important atmospheric processes, including secondary organic aerosol (SOA) formation.  There has been very little exploration of the photo-oxidation reactions of VOC’s emitted in quantity by Australian vegetation, for instance, those of eucalyptol (1,8-cineole).  In this project, compounds of interest will be photo-oxidized under controlled conditions using the Indoor Smog Chamber at CSIRO Lucas heights and analysed via GC- and LC-MS after derivatisation.

Deceptive Orchids: Signals and Pollination

(with Dr Marie Herberstein & Anne Gaskett, Department of Biological Sciences)

Orchids are famous for their unusual deceptive pollination systems, and Australia is a global hotspot for orchid deception. If you are seeking a project involving charismatic study species, independent fieldwork, and broadly-applicable lab skills, this interdisciplinary project may suit you.

'Food-deceptive' orchids do not provide a nectar reward for their pollinators. Instead, they are thought to attract pollinators by mimicking the colours and scents of other flowers. We are interested in the evolution of this mimicry, and in assessing the colour and scent signals without the biases of human perception.

Fieldwork will be required in Sydney and NSW to monitor native orchid pollination rates, collect pollinating insects, and collect flowers from orchids and other plants. Floral colours will be analysed by spectrometry in the Department of Biological Sciences. Floral scents will be analysed by gas chromatography and gas-chromatography-mass spectrometry in the Department of Chemistry & Biomolecular Sciences.

We are seeking a student with a background in evolutionary biology and/or chemistry. We will teach you all the field and lab techniques, and we can develop the project according to your strengths and interests.

Your own car would be an advantage for fieldwork, but it is not essential. The project is well-funded, permits have been applied for, and we are ready to go with the right person. Furthermore, you'll be joining dynamic labs that combine innovative science with great peer-support. Visit our web pages and feel free to contact us for more information.

See also the web pages of Mariella and Anne

“The foundation of every state is the education of its youth” – Diogenes

The Pedagogy of Laboratory-Based Teaching and Learning

Laboratory-based teaching and learning is generally, but not universally, accepted as a fundamental element in science education.  While our understanding of teaching and learning processes has advanced through education research, the application of this knowledge to the laboratory has lagged behind.  We are interested in addressing a number of general educational questions relating to laboratory-based teaching and learning, such as what are the purposes of teaching in laboratories, what strategies are available for teaching in laboratories and how are they related to the purposes and how might we assess the outcomes of laboratory instruction?

Of particular interest is identifying how generic skills and graduate attributes may be developed in the laboratory context.  Laboratory work provides ample opportunities for students to cultivate skills such as collecting, analysing and organising information, communicating ideas and information, planning and organising activities, working alone and in teams, using mathematical ideas and techniques, solving problems and using technology.

The Australasian Chemistry Enhanced Laboratory Learning Project

Mathematics in Chemistry Education

Anecdotal evidence suggests that the many science students are finding the mathematical aspects of their courses to be difficult and therefore a barrier to their studies.  We are interested in determining if anecdotal evidence can be supported by research, in discovering why this position has come about, and developing approaches to achieve the desired learning outcomes for our graduates, which includes the ability to use mathematical tools in a confident and competent manner.

Maths Anxiety in Chemistry Students

Maths anxiety is described in a number of ways, but the common themes are that a sufferer feels, to greater or lesser extent, panic, helplessness, paralysis, and mental disorganization.  This may mean that the student stops him- or herself from starting on a task, even if capable of doing it.  Students may be caught in a cycle of maths avoidance when, in the past, the student has suffered a bad experience relating to maths.  The student then avoids mathematical tasks, resulting in poor mathematical preparation.  This then leads to more negative maths experiences, reinforcing negative perceptions, and hence completing the cycle.  In the milder form of this behaviour, simple reassurance and guidance may be sufficient to break the cycle.  In the stronger form, this will result in a true lack of mathematical preparation and a fear of doing anything about it.  The protocol for dealing with students suffering from maths anxiety should be different from that for those students simply lacking adequate mathematical skills, but without anxiety.  For this reason it is necessary to measure the extent of maths anxiety amongst the student cohort, and develop mechanisms for identifying these people early in their studies, so that appropriate support for them can be provided.

Chemical Misconceptions and Constructivism

“Constructivism” refers to the theory that the process of learning is not one of simple acceptance and remembrance of facts, but one where the learner must incorporate them into an already constructed world-view.  If that world-view can not be modified to fit the new knowledge, then the knowledge is not retained.  In other words, the learner must construct meaning for the knowledge for it to be preserved.   It is therefore necessary for teachers to understand the ways in which students incorporate knowledge into their “world-views”.  Students bring with them many preconceptions and/or misconceptions.  These form the scaffolding on which students build all subsequent knowledge, unless they are distinguished, confronted and replaced or reconstructed in line with modem scientific thinking. Preconceptions in chemistry are extremely persistent. There is typically a rapid evolution in fundamental ideas about chemistry between the ages of 6 and 12, but only very slow change thereafter, in spite of intensive instruction in chemistry. These misconceptions are likely to still be present in tertiary level students, right through to those studying for their Ph.D.’s.  It is important that teachers are aware of the range of preconceptions and misconceptions that students bring with them, and put in place appropriate teaching methods that adequately address these issues.

CBMS112:  - Advanced Chemistry 1A

CBMS207 - Physical Chemistry

CBMS329 - Topics in Physical Chemistry