Welcome from the Computational Modelling Group
Welcome to the website of the CoMo Group. We develop and apply modern numerical methods to problems arising in Chemical Engineering. The overall aim is to shorten the development period from research bench to the industrial production stage by providing insight into the underlying physics and supporting the scale-up of processes to industrial level.
The group currently consists of 18 members from various backgrounds. We are keen to collaborate with people from both within industry and academia, so please get in touch if you think you have common interests.
The group's research divides naturally into two inter-related branches. The first of these is research into mathematical methods, which consists of the development of stochastic particle methods, computational fluid dynamics and quantum chemistry. The other branch consists of research into applications, using the methods we have developed in addition to well established techniques. The main application areas are reactive flow, combustion, engine modelling, extraction, nano particle synthesis and dynamics. This research is sponsored on various levels by the UK, EU, and industry.
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Preprint 238 published
Preprint 238, "Understanding the anatase-rutile stability in flame-made TiO2", has been published!
The relative stability of anatase and rutile in stagnation flame synthesis with stoichiometric mixtures is investigated experimentally. The measurements reveal a high sensitivity of anatase-rutile composition to the flame dilution. It is demonstrated that anatase formation is favoured in more dilute (colder) flames while rutile is favoured in less dilute (hotter) flames. A particle model with a detailed description of aggregate morphology and crystal phase composition is applied to investigate the anatase-rutile stability. A size-dependent phase transformation model is implemented in which rutile is formed for particles larger than a "crossover" size while anatase is formed for those smaller. Two formation mechanisms/pathways are discussed and evaluated. In the first pathway, the nascent particles are assumed to be stoichiometric and the crossover size is given by thermodynamic quantities. This hypothesis captures the general trend in the measured anatase-rutile composition but fails to explain the sensitivity. In the second pathway, non-stoichiometric TiO2-x oxide intermediates are assumed and the crossover size is hypothesised to be composition-dependent. This shows an excellent agreement with the experimental data. However, this hypothesis is found to be strongly influenced by assumptions about the initial particle growth stages. This study demonstrates the importance of a better description of the high-temperature chemistry and initial clustering mechanism in order to understand the crystal phase formation.
Prof. Kraft wins prestigious German research prize
Professor Markus Kraft, head of the CoMo group and Director of CARES, has received one of Germany's top research prizes, the Friedrich Wilhelm Bessel Research Award. The award is given in recognition of an outstanding record of scientific achievement for internationally renowned scientists, particularly those whose work is expected to have a formative influence on their discipline.
Professor Kraft was awarded the prize in June at the opening ceremony of the Alexander von Humboldt Foundation's annual conference, held at Freie Universität in Berlin. The ceremony was attended by German Chancellor Angela Merkel, who gave the opening speech. Professor Kraft's visit to Germany was hosted by Professor Christof Schulz, the director of the reactive fluids research group at the Institute for Combustion and Gas Dynamics, University of Duisburg-Essen.
Award recipients are invited to collaborate with colleagues on a long-term research project in Germany. One aim of Professor Kraft's proposed collaboration is to develop detailed multi-scale models which are able to describe the influence of operating conditions of a reactor or burner on the chemical growth and the product properties of inorganic (e.g. titania) and organic nanoparticles (e.g. soot and carbon black). Such models can be used, among other applications, to optimise nanoparticle properties with respect to energy requirements, emissions and product quality. For example, nanoparticle films created from a laminar burner can be used as (electro)catalysts. This process has the potential to be applied in industry as it is easily scaled up.
Professor Kraft's early research career was spent in Germany, where he completed his Doctor rerum naturalium (equivalent to a PhD in Natural Sciences) in Chemistry at University of Kaiserslautern. He subsequently worked at the University of Karlsruhe and the Weierstrass Institute for Applied Analysis and Stochastics in Berlin. In 1999 Professor Kraft became a lecturer in the Department of Chemical Engineering, University of Cambridge. He is now a professor in the department and leads the Cambridge CARES programme in Singapore.
Photo: Professor Kraft receiving his award from Hans-Christian Pape, President of the Alexander von Humboldt Foundation. Credit: © Jens Jeske/Humboldt-Stiftung
Best student oral presentation at the Carbon conference 2019
PhD student Jacob Martin has won the 2019 Mrozowski Award for best oral presentation at the 2019 Carbon conference. The Mrozowski Award is for best oral presentation by a student at international carbon conferences organised and/or sponsored by the American Carbon Society.
Carbon is the world’s premier conference on carbon science, running annually with 450-600 attendees from around the world. This year’s conference ran for six days in Lexington, Kentucky and hosted more than 200 presentations, along with poster sessions. Jacob attended Carbon with fellow PhD student Angiras Menon. Jacob and Angiras presented a number of talks from the University of Cambridge Computational Modelling Group:
- Understanding the lack of fullerenes in fullerene-like carbons, by J. Martin
- Flexoelectricity and the electrical aspects of carbon formation in flames, by J. Martin
- Topology of disordered graphene networks, by J. Martin
- Impact of crosslinks, curvature and radical character on the optical band gap of nanographenes, by A. Menon
- Degree of crosslinking in combustion carbons, by L. Pascazio
- Investigating the self-assembly and structure of nanoparticles containing curved carbons, by K. Bowal
If you’re interested in reading more about this year’s Carbon conference, Jacob has written a blog post that contains his presentations and highlights some of the other exciting research that was presented.
Photo: Jacob and Angiras at the end of a long week.
Preprint 236 published
Preprint 236, "Linking Reaction Mechanisms and Quantum Chemistry: An Ontological Approach", has been published!
In this paper, a linked-data framework for connecting species in chemical kinetic reaction mechanisms with quantum calculations is presented. A mechanism can be constructed from thermodynamic, reaction rate, and transport data that has been obtained either experimentally, computationally, or by a combination of both. This process in practice requires multiple sources of data, which raises several issues. For example, the same species may have been given different names by different authors, whereas other species may have been given the same name even though they are distinct entities. Secondly, thermodynamic, reaction rate, and transport data may be inconsistent, with large variations outside stated error bounds between different sources. A linked data-centric knowledge-graph approach is taken in this work to address these challenges. In order to implement this approach, two existing ontologies, namely OntoKin, for representing chemical kinetic reaction mechanisms, and OntoCompChem, for representing quantum chemistry calculations, are extended. In addition, a new ontology, which we call OntoSpecies, is developed for uniquely representing chemical species. The framework also includes agents to populate and link knowledge-bases created through the instantiation of these ontologies. In addition, the developed knowledge-graph and agents naturally form a part of the J-Park Simulator (JPS) - an Industry 4.0 platform which combines linked data and an eco-system of autonomous agents for cross-domain applications. The functionality of the framework is demonstrated via a use-case based on a hydrogen combustion mechanism.
Preprint 234 published
Preprint 234, "Reactivity of polycyclic aromatic hydrocarbon radicals: implications for soot formation", has been published!
This paper presents a systematic study of the reactivity of polycyclic aromatic hydrocarbons (PAH), identifying crosslinks that permit the combination of physical π-stacking interactions and covalent bonding. Dispersion corrected hybrid density functional theory was used to identify the location of reactive sites on PAHs using the average local ionisation potential. The bond energies formed between these various reactive sites were then computed. σ-radicals were found to be the most reactive, forming bonds with other radicals and some reactive closed shell edge types. Partially saturated rim-based pentagonal rings were found to form localised π-radicals with high reactivity. This site, in addition to resonantly stabilised π-radicals, was found to be capable of bonding and stacking, which is explored for a variety of larger species. Localised π-radicals, in particular, were found to form strongly bound stacked complexes indicating a potentially important role in soot formation.
Blockchain paper wins Highly Cited Paper Award
The award will be presented during the 2019 ICAE conference.
Best oral presentation award at ICMAT 2019
Research by Prof. Markus Kraft (University of Cambridge), Prof. Xu Rong and Dr Sheng Yuan (both of Nanyang Technological University) has won an award at the 10th International Conference on Materials for Advanced Technologies (ICMAT).
The research was conducted at the Cambridge Centre for Advanced Research and Education in Singapore (CARES).
Dr Sheng Yuan won the best oral presentation award for his presentation ‘One-Step Flame Synthesis of Phosphorous-Doped Ni-Fe/C Nanocomposite Films for Electrocatalytic Oxygen Evolution Reaction’ on 28 June 2019. The conference had 3,500 attendees and 45 technical symposia. About one best oral presentation was selected for each symposium. Yuan currently works in the Singapore lab of CARES. His main research interest is the scalable synthesis of nanomaterials for energy and environmental technologies.
Photo: Sheng Yuan presented on stage with Nobel laureate Sir J. Fraser Stoddart and other award winners.
Preprint 230 published
Preprint 230, "OntoPowerSys: A Power Systems Ontology for Cross Domain Interactions in an Eco Industrial Park", has been published!
Knowledge management in multi-domain, heterogeneous industrial networks like an Eco Industrial Park (EIP) is a challenging task. In the present paper, an ontology based management system has been proposed for tackling this challenge. It focuses on the power systems domain and provides a framework for integrating this knowledge with other domains of an EIP. The proposed ontology, OntoPowSys is expressed using a Description Logics (DL) syntax and OWL2 language was used to make it alive. It is then used as a part of the Knowledge Management System (KMS) in a virtual EIP called the J-Park Simulator (JPS). The advantages of the proposed approach are demonstrated by conducting two case studies on the JPS. The first case study illustrates the application of Optimum Power Flow (OPF) in the electrical network of the JPS. The second case study plays an important role in understanding the cross domain interactions between chemical and electrical engineering domains in a biodiesel plant of the JPS. These case studies are available as web services on the JPS website. The results showcase the advantages of using ontologies in the development of decision support tools. These tools are capable of taking into account contextual information on top of data during their decision making process. They are also able to exchange knowledge across different domains without the need for a communication interface.
PhD position in Aerosol Science
The EPSRC Centre for Doctoral Training in Aerosol Science is offering a number of fully-funded PhD studentships. Students will spend their first 7 months at the University of Bristol taking courses in aerosol science before moving on to their final university placement. Within this CDT, a placement on the topic "Modelling the plasma synthesis of graphene" is available at the Computational Modelling Group.
Plasma synthesis offers a potential route for the bulk synthesis of graphene. Advantages include avoiding the need for a catalyst (thus avoiding the use of rare-earth metals) and the ability to operate at atmospheric pressures (which reduces the cost and complexity of the process), both of which potentially make the process easier to scale up than other manufacturing routes. However, there remains a lack of understanding of how the process variables, such as temperature, affect the quality of the product. The choice of process conditions and reactants is critical to avoid undesirable defects in the carbon structure.
The purpose of this project is to develop a model to explain the processes controlling graphene plasma synthesis. During the project the student will:
- Extend existing Kinetic Monte Carlo models for the growth of carbonaceous nanomaterials to test different hypotheses to explain the observations made in graphene experiments.
- Estimate thermodynamic data and rate constants using Density Functional Theory (DFT) calculations.
- Expand current understanding of the chemistry of polycyclic aromatic hydrocarbons and their role in the graphene, carbon nanotube and carbonaceous particles chemistry.
CoMo group open to Feodor Lynen Research Fellows
In 2016, Prof. Markus Kraft was awarded the Friedrich Wilhelm Bessel Award and is therefore eligible to host Feodor Lynen Research Fellows sponsored by the Alexander von Humboldt Foundation. The Feodor Lynen Research Fellowship covers the salary and travel expenses of researchers from Germany to work at the host institution for 6-24 months. In addition, the fellowship enables the successful candidate to apply for alumni sponsorship from the Humboldt Foundation after the end of the fellowship and become part of their international network of academics.
If you are interested in working at the University of Cambridge and in joining the CoMo group as a post-doctoral researcher, please check your eligibility on the official Feodor Lynen Research Fellowship website and familiarise yourself with the application procedure. You will need to write a research proposal that aligns with your professional expertise. The topic might be of computational or experimental nature but should lie within the research areas of the CoMo group.