Monday, 16 February 2015

Xinyan Huang wins Qatar Petroleum Medal for research on Clean Fossil Fuels

I am delighted t announce that my PhD student Xinyan Huang, working on peat fires, has been awarded the Qatar Petroleum Medal for PhD Research Excellence in Clean Fossil Fuels.
Xinyan (center) receives the QP Medal from Dr Naji Saad
during the award dinner at 170 Queens Gate.
Prof Blunt is to his left.

Xinyan wearing the QP Medal and the happy supervisor.

 The Press Release from Imperial reads:  

The Qatar Petroleum Medal and Prize for Research Excellence in Clean Fossil Fuels is awarded annually to a PhD student at Imperial College London who is in their third or fourth year of study. Sponsored by Qatar Petroleum, through the Qatar Carbonates and Carbon Storage Research Centre (QCCSRC), the award is to recognise their outstanding achievements in the field of Clean Fossil Fuels.

This year’s prize of £1000 and a commemorative medal has been awarded to Xinyan Huang from the Department of Mechanical Engineering. In a field of very strong candidates, it was his achievements in research and his publication record that impressed the judges. “Xinyan has been a fantastic student since he started here in 2012, it is a joy to work with someone like him who can seamlessly combine experiments and modelling to answer scientific questions” says Dr Guillermo Rein (that is me!), Xinyan’s PhD supervisor “I think this award recognises that he has been a valuable member of the engineering community both here at Imperial but also in the wider Clean Fossil Fuels field.” Xinyan’s thesis is a computational and experimental study of the chemical, heat and mass transfer mechanisms governing the smouldering combustion of peat. His research focuses on peat, which is essentially a young coal, and is providing a fundamental understanding of the accidental burning of this sub-fossil fuel. These are the largest fires on Earth with a massive carbon footprint. He has written numerous significant peer-reviewed papers and presented his work at conferences and seminars in the UK, Europe and further afield. 

“Xinyan’s work has brought new insight and quantitative modelling to an important, but to date under-studied, source of carbon emissions, peat combustion,” says Professor Geoff Maitland, Founding Director of QCCSRC “He joins a list of previous winners who have gone on to successful careers in industry and academia and we will wish Xinyan well in his future endeavours.” 

As well as conducting his research, Xinyan is a Teaching Assistant at Imperial and has been a Visiting Scholar at University of Science and Technology in China and at the National University of Singapore. The Qatar Petroleum Medal and Prize was awarded to Xinyan at the dinner during the QCCSRC Annual Review. QCCSRC is based within the Department of Chemical Engineering and the Department of Earth Science and Engineering.

Tuesday, 3 February 2015

Wildfires and the burnig of Pine needles


In our recent paper published in Fire and Materials, we use laboratory experiments to investigate the differences in fire dynamics between live and dead pine needles. This is important because limited research has been conducted on the burning characteristics of live fuels, which are commonly assumed to behave like moist dead fuels.

The high flammability of conifer forests in the Mediterranean and Boreal biomes is due mostly to the presence of needles in very large amounts. Needles are fine fuels that ignite and spread flames faster than coarse woody fuels and represent an important portion of the total fuel consumption in wildfires. Needles are found both in the tree canopies and on the ground. Live needles (green colour) are part of the foliage and typically burn in crown fires. Dead pine needles (red colour) are on the ground, accumulating gradually on the litter and humus layers, and burn both in surface and ground fires.


Samples of Pinus halepensis needles used in the experiments (from left to right): live, aged and dead.

Our fire calorimetry results show good repeatability and demonstrate that the difference in burning dynamics of live and dead pine needles is significant and can be quantified and understood. Using a series of 10 flammability parameters extracted from the experiments, we show that the most flammable samples are fresh dead needles, followed by dry dead and dry live needles. The least flammable is fresh live needles. Live needles ignite about four times slower, and burn with ~60% lower power and ~50% lower heat of combustion than dead needles. The results confirm the importance of moisture content in the burning behaviour of pine needles, but the differences between live and dead samples cannot be explained solely in terms of moisture but require consideration of plant chemistry and sample drying.

(Left) Time to ignition and (Right) flaming time.

The results show that there are fundamental differences in the physics and chemistry of the flames of these fuels and that fire dynamics does not follow a simple trend from live to aged and to dead fuels.

Our results also defy the common assumption that oven drying only affects the water content of samples, or that the drying conditions are not important. Data suggest that observed fire behavior is substantially affected by the drying process in the oven, which induces chemical and structural changes (eg, loss of volatile organic compounds inside the oven). The fact that oven drying is widely used in wildfire laboratory studies merits more research.



- F Jervis, G Rein, Experimental study on the burning behavior of Pinus halepensis needles using small-scale fire calorimetry of live, aged and dead samples, Fire and Materials (in press) 2015.  http://dx.doi.org/10.1002/fam.2293  (open access)

Thursday, 22 January 2015

Doubt cast on global firestorm generated by dino-killing asteroid

Pioneering new research published in the Journal of the Geological Society.has debunked the theory that the asteroid that is thought to have led to the extinction of dinosaurs also caused vast global firestorms that ravaged planet Earth.


A team of researchers from the University of Exeter, Imperial College London, Planetary Science Institute and University of Vienna recreated the immense energy released from an extra-terrestrial collision with Earth that occurred around the time that dinosaurs became extinct. They found that the intense but short-lived heat near the impact site could not have ignited live plants, challenging the idea that the impact led to global firestorms.

These firestorms have previously been considered a major contender in the puzzle to find out what caused the mass extinction of life on Earth 65 million years ago.
The researchers found that close to the impact site, a 200 km wide crater in Mexico, the heat pulse - that would have lasted for less than a minute - was too short to ignite live plant material. However they discovered that the effects of the impact would have been felt as far away as New Zealand where the heat would have been less intense but longer lasting - heating the ground for about seven minutes - long enough to ignite live plant matter.

The experiments were carried out in the laboratory and showed that dry plant matter could ignite, but live plants including green pine branches, typically do not.

Dr Claire Belcher from the University of Exeter said: “By combining computer simulations of the impact with methods from engineering we have been able to recreate the enormous heat of the impact in the laboratory. This has shown us that the heat was more likely to severely affect ecosystems a long distance away, such that forests in New Zealand would have had more chance of suffering major wildfires than forests in North America that were close to the impact.  This flips our understanding of the effects of the impact on its head and means that palaeontologists may need to look for new clues from fossils found a long way from the impact to better understand the mass extinction event.”
Plants and animals are generally resistant to localised fire events - animals can hide or hibernate and plants can re-colonise from other areas, implying that wildfires are unlikely to be directly capable of leading to the extinctions. If however some animal communities, particularly large animals, were unable to shelter from the heat, they may have suffered serious losses. It is unclear whether these would have been sufficient to lead to the extinction of species.

Dr Rory Hadden, who was part of Dr Guillermo Rein's group in Imperial College by the time of the research and now is at the University of Edinburgh, said: “This is a truly exciting piece of inter-disciplinary research. By working together engineers and geoscientists have tackled a complex, long-standing problem in a novel way. This has allowed a step forward in the debate surrounding the end Cretaceous impact and will help geoscientists interpret the fossil record and evaluate potential future impacts. In addition, the methods we developed in the laboratory for this research have driven new developments in our current understanding of how materials behave in fires particularly at the wildland-urban-interface, meaning that we have been able to answer questions relating to both ancient mass extinctions at the same time as developing understanding of the impact of wildfires in urban areas today.”


The research was supported by a European Research Council Starter Grant, a Marie Curie Career Integration Grant, the Leverhulme Trust, the EPSRC and the Austrian Science Fund

Tuesday, 20 January 2015

Research Associate position on fire protection engineering in Imperial College London



Research Associate in the Thermofluids Division at the Department of Mechanical Engineering, Imperial College London.

Maximum salary on appointment will be £33,410 per annum*
*Candidates who have not yet been officially awarded their PhD will be appointed as Research Assistants within the salary range £29,350 - £32,520 per annum.

Fixed-term appointment available for up to 8 months in the first instance.

The Thermofluids Division wishes to appoint a Research Associate to conduct research into systemic fire protection engineering at Imperial College London.

The Hazelab is the multidisciplinary research group led by Dr Guillermo Rein and part of the Thermofluids Division in the Department of Mechanical Engineering. The purpose of the group is to reduce the worldwide burden of accidental fires and protect people, their property, and the environment. To do so, Hazelab studies computationally and experimentally heat transfer processes, condensed-phase chemistry and thermodynamics of reactive solids.

The Research Associate under the supervision of Dr Rein, will be involved in the project N-LAYERS to conduct a study and write a white paper where a holistic view of fire protection engineering is created and the role of prevention is examined. Fire safety is made of a series of layers (e.g., prevention, fuel control, passive and active systems, evacuation, and structural response). All layers have a role in fire safety, but not all layers are equally important, effective or costly. In this context, N-LAYERS wants study in-depth the role of prevention in a systemic view of fire protection.

The Associate would be in charge of conducting the multidisciplinary literature review on systemic thinking, resilience and layers of fire protection; construction of a novel framework for the white paper based systemic thinking; communicate with collaborators; and write the white paper.

A PhD (or equivalent experience and/or qualifications) or near completion of a PhD* in an area pertinent to the research subject e.g. Fire Protection Engineering, Mechanical Engineering or Chemical Engineering is essential.  In addition some background in fire dynamics and risk is also essential. High quality writing in technical English is desirable.

Informal e-mail enquiries may be made to Dr Guillermo Rein at g.rein@imperial.ac.uk or +44(0) 20 7594 7036.

Committed to equality and valuing diversity.  We are also an Athena SWAN Silver Award winner, a Stonewall Diversity Champion, a Two Ticks Employer and are working in partnership with GIRES to promote respect for trans people.
                               
Closing Date:  20 February 2015 (midnight GMT)
                               
How To Apply:                  
Our preferred method of application is online via our website.  Visit at http://tinyurl.com/hazelab or go to http://www3.imperial.ac.uk/employment (Select “Job Search” then enter the job title or vacancy reference number into “Keywords”). Please complete and upload an application form as directed quoting reference number EN201500023SF, you must submit an application form for our posts along with a CV, if you do not fill in an application form, you will not be considered.

Alternatively, if you are unable to apply online, please email Ms Claire Soulal, Academic Administrator at: c.soulal@imperial.ac.uk to request an application form.

Wednesday, 7 January 2015

Peat fires - a legacy of carbon up in smoke

Press Release:

It reads like a movie script – ash falling from the sky, thick smoke shutting down airports and businesses, road closures trapping remote northern villages. But this is not from a script; rather, it is a new study of what could happen through peat burning.

In an international paper released in the January edition of the journal Nature Geoscience, the researchers, led by University of Guelph professor Merritt Turetsky, focus on fires that burn through thick layers of peat (dead plant debris) that blanket the ground in ecosystems ranging from the tropics to the arctic.

Peat is a legacy of plant activity – plants acquiring carbon from the atmosphere to build their biomass. Those plants die and are incorporated into the soil. When those soils are too wet to support high levels of decomposition, those plant remains pile up over time.

"When people picture a forest fire, they probably think of flames licking up into tree tops, and animals trying to escape," said Turetsky. "But peat fires tend to be creeping ground fires. They can burn for days and weeks, even under relatively wet conditions. They lack the drama of flames, but they produce a lot of smoke." That smoke makes peat fires dangerous to human health. It can worsen air quality and even trigger asthma and other respiratory problems. "We know fires serve as a major source of human mortality globally," said Turetsky. "We are starting to understand that peat fires cause some of the most extreme air quality issues, but in general they are poorly understood." Turetsky and Brian Benscoter teamed up with fire scientists to summarize what is known about peat fires, from massive lightning-ignited fires that burn large areas of the boreal region to tropical fires often triggered by human activity.

"The tropical peatlands in Southeast Asia are a clear demonstration of how human activity can alter the natural relationships between ecosystems and fire," said Susan Page, a University of Leicester professor and co-author on this study. "Tropical peatlands are highly resistant to natural fires, but in recent decades, humans have drained peatlands for plantation agriculture. People cause the deep layers of peat to dry out, and also greatly increase the number of fire ignitions. It's a double threat." This causes a host of problems, including health issues, airport and school closures, and political tensions. The paper concludes that almost all peat-rich regions will become more susceptible to drying and burning with a changing climate.

“Thanks to satellite data, we are fully aware of the vast scale of burning in drained peatlands, mostly in Indonesia,” said co-author Guido van der Werf, a professor at Amsterdam’s VU University and and co-author on this study. “The scary thing is future climate change may actually do the same thing: dry out peatlands. If peatlands become more vulnerable to fire worldwide, this will exacerbate climate change in an unending loop." Peatlands store a large amount of carbon due to thousands of years of plant activity. When peat burns, carbon is released into the atmosphere.

 “Smouldering peat fires already are the largest fires on Earth in terms of their carbon footprint,” said Dr Guillermo Rein from Imperial College London, and and co-author on this study.

Peat fires and their effects will only increase as more towns are built and more resources developed near peat-rich regions, said Turetsky. “These types of fires have different impacts on ecosystems, and traditional fire management techniques will not be effective in combating peat fires. We need new tools to deal with these issues,” she said. The study is titled “Global vulnerability of peatlands to fire and carbon loss.”

Contacts: Guillermo Rein, Imperial College g.rein at imperial.ac.uk

Friday, 26 December 2014

Peat fires and carbon loss

Together with co-authors in Canada, US, UK and Netherlands, we have just published a progress article in Nature Geoscience  (vol 8, 2014) on the carbon losses from peat fires: Global vulnerability of peatlands to fire and carbon loss.

Ssmouldering combustion of dry peat.Available at Imaggeo.
In the paper we review how fire is a threat to the naturally stored carbon in peatlands and has the potential to drastically disturb the carbon stocks. While dry peat is a very flammable substance because it is a porous and carbon-rich, the amount of carbon stored in peatlands exceeds that stored in vegetation globally. Peat fires are dominated by smouldering combustion, which is ignited more readily than flaming combustion but is more difficult to suppress. In fact smouldering fires can persist deeper and in much wetter conditions than flaming fires. In very wet or flooded peatlands, most of the carbon stock typically is protected from smouldering, and resistance to fire has led to a build-up of peat carbon storage in boreal and tropical regions over long timescales. But drying as a result of climate and human activity (eg, drainage) lowers the water table and increases the frequency, depth and extent of peat fires. The combustion of deep peat affects older soil carbon that has not been part of the carbon cycle for centuries to millennia, and thus dictates how fire emissions affect the carbon cycle and feedbacks to the climate.

Monday, 22 December 2014

Fin's and Candle's Creative Contests

Engineering can be the most creative profession, but we engineers are in general not the best communicators nor the best at appreciating arts. These are not really topics of interest in Engineering Schools around the world.
Sir John O'Reilly said it better during the 2014 Mountbatten Lecture at the Royal Institution, "Engineers should embrace the arts as being key to creativity and an important component of innovation, crucial to creating new products and boosting future competitiveness". Sir John is also proposing to change STEM to STEAM (science, technology, engineering, arts and maths) and he has my support.

I always want to build on this and encourage somehow my students' motivation on communications and the arts. So this year, again, I started the academic year with Creative Contests for each my courses at Imperial College: ME2 Heat Transfer and ME4 Combustion. The instructions to participate were the following: "I have three extra copies of the textbook to give away. If interested, send me a poem, comic, drawing, painting, song, video, or anything creative that explains why you are taking this course. Art, wit and humour are allowed, even encouraged". I show below the submissions; congratulations to the winners (I wish an extensive use your new awarded textbooks).

2014 Fin's Creative Contest in ME2 Heat Transfer: 

I was the sole jury and found three winners (the first three shown here), each received a hard copy of Incropera's Foundations of Heat Transfer. These are the submissions:



  • Instrumental composition written and played by Daniel (note: the piano stands for convection in water, the mandolin for an insulator and the djembe for conductive material)



  • The Infamous Microwave problem drawn by Riyadh
     


  •  Roses are red written by Daniel


  • Heat Transfer poem written by Sofie



  • The Phoenix painted by Johan
     



  • Cold hands and feet written by Rob
     

  • There was once a man called Guillermo written by Thomas

  • Who needs to learn Heat Transfer? drawn by Adrian




  • Heat Transfer Hits Volume 1 collected by Hisham

  • Letter to Incropera written by Anni



  • 2014 Candle's Creative Contest in ME4 Combustion 

    I asked the class to be the jury via a Memtimeter survey and they found three winners (the first three shown here), who got a hardcopy of McAllister's Fundamentals of Combustion Processes. The three runners up (following three submission) got a copy of Faraday's Chemical History of a Candle. These are the submissions:



  • Tournament website created by Sven


  • The Burning Crusade drawn by Qunli


  • How many combustion phenomena can you find? drawn by Haoxiang

  • Life of a candle composed by Wei




  • Flames painted by Franz
     




  • Our modern life composed by Siying

  • Shock diamond selected by Francis  (credit: Swiss Propulsion Laboratory

    Note: see here for the 2013 Contests I organized last year

  • Saturday, 27 September 2014

    Forecasting the movement of a wildfire

    I have a dream too. That one day we could predict the movement of a fire and be able to inform the Fire Service ahead of time by using just an iphone.

    Hopefully our recent paper (published in open access) in Natural Hazards and Earth System Sciences moves us closer to that end, as it reports an algorithm that can forecast the movement of a wildfire when observations of the locations of the flames are available.


    Five assimilated fire fronts with 1 min intervals (black solid lines). The first guess (red dashed line) is taken to be far from the true invariants vector to check the algorithm capability to converge. A 10 min forecast (blue solid lines) is also calculated using fuel depth as sensor data.
    The title of the paper is "Forecasting Wind-Driven Wildfires Using An Inverse Modelling Approach". The fire model at the core of the forecast algorithm combines the classical theory of Rothermel's rate of spread with a perimeter expansion model (based on Huygens principle for the propagation of waves). We then pose the  problem as an optimisation and force our fire model to predict well any past observations of the real fire that might be avaible at that moment. Observations of the location of the fire can be produced from any system like from personnel in the field (deployed fire fighters), drones, airplanes or satellites. Once all the past observations are predicted, we consider that we have found the true characteristics of this particular fire and launch forecasts into the future. Where would be this fire be in 10 min or 1 h?

    We have investigated the skills of the algorithm using synthetic data (not real fire data) and the results show it is very quick and decently accurate, and predicts the location of the front ahead of time. It needs further work to increase its accuracy, of course, but we already see the greatest strengths of our method are lightness, speed and flexibility. We specifically tailor the forecast to be efficient and computationally cheap so it can be used in mobile systems for deployment by the Fire Service. For example, in an iphone.

    Hope Apple knock on our door one day.

    Sunday, 3 August 2014

    Welcome Nils to Imperial Haze Lab


    July was the first month of Nils Roenner at Imperial College London as a new PhD student in m group. He joins the Imperial Haze Lab in the Department of Mechanical Engineering.

    Nils is from Germany. He has just graduated with an MEng degree in Mechanical Engineering from Imperial College. In his final year project, he studied numerically the pyrolysis and ignition of polymers subjected to transient irradiation. During his degree, he has also work on a novel device for energy recovery from wood burning stoves. During the summers, he hold internships in several companies, spanning the foundry, mechatronics and electronics sectors.

    The preliminary title of his thesis is "Experimental Investigation on the Boosting of Flame Retardancy in Thermoplastics" and is funded by BASF, Germany. The aim of the thesis is to provide a better understanding of the fundamental chemical and heat transfer processes involved in the ignition of thermopastics. In this work, Nils aims at improving the prevention of residential and industrial fires.

    Monday, 16 June 2014

    Nature’s sport and the Burning Mountain

    Figure 1. Newspaper excerpt from 1828 announcing an active volcano in Australia.
    Thanks to his knowledge in geology and an investigation of the site, Reverend Charles Wilton ended the rumors of an active volcano in Australia (Fig. 1). In 1829, Rev. Wilton visited Mount Wingen in New South Wales, Australia, and pronounced the phenomenon to be unique, "one other example of nature’s sports", a fire that had been burning for a very long time, "far preceding the memory of man". Indeed, wingen is the word for fire in the aboriginal language of the local Wonaruah tribe.


    Mount Wingen, 530 m above sea level, is the highest of two contiguous hills in the Upper Hunter Valley. It is located 25 km North of Scone via the New England Highway and approximately 4 hr drive from Sydney. Its official name is the Burning Mountain Nature Reserve, and I had the pleasure of visiting it in early February 2014 (Fig. 2). The visit fulfilled one of my most desired field trips. I was attending the 11th International Symposium on Fire Safety Science in New Zealand, and I could not forgive myself from a quick stop over to see the Burning Mountain.



    Figure 2. Entry to the Nature Reserve of The Burning Mountain, including my symposium bag.

    The nature's sport that Rev. Wilton was referring to is the smouldering combustion of a coal seam. The Burning Mountain is the best example of this natural phenomenon that slowly burns the underground coal when it becomes exposed to atmospheric air.  Smouldering is the slow, low-temperature, flameless burning that represents the most persistent type of combustion phenomena and leads to the largest and longest burning fires on Earth. This Australian coal seam started to burn more than 6,000 years ago, some scientists think more than 500,000 years ago. At least the British cannot be blame for it.

    The fire is burning now about 30 m below ground. At a rate of 1 m per year, the fire has now reached the top of the hill which shown in Figure 3. Because of the creeping spread rate, the slow intense heat has created a landscape clear of any vegetation 50 m around. The soil shows an beautiful colour palette of white sinter, yellow sulphate, black char and red iron oxide. Where the fire and heat has not reached yet, a healthy forest of mature and tall trees can be seen on brown soil. Along the former trail of the fire path, the forest grows back slowly, and young and smaller trees can be seen on red soil. Once at the hilltop, it is easy to feel the hot combustion gases and the smell of sulfur released from multiple deep cracks. The site is surrounded by cracks, some are up to 0.5 m wide, which are more visible ahead of the fire than behind it. Further from the active site by about 20 m, the cracks do not emit gases which to me indicates that the airflow direction is into the seam, feeding the fire with vital oxygen.

    Figure 3. The fire has now reached the top of the second hill, where the soil is also a multicolor palette of white sinter, yellow sulphate, black char and red iron oxide.
    Some of the most interesting observations that the visitor can do are visually inspections of the trail the fire has left in the area as it has spread for centuries. The entry to the walking track is from the New England Highway, about 1km North of the current fire location (Fig 4). As the visitor walks in from the parking lot, the track goes up to the tallest of the two contiguous hills. Near the hill top, the visitor meets the first clear signs of the fire trail, and then the track follows it chronologically. The fire was burning below the hill top circa 1500s (my estimate). One can see a clear change to less dense vegetation, soil of a strong red colour and more large rocks on the ground. Then, the track goes down a few dozen meters to the saddle point between the two hills and then up to the current fire site. This saddle point is close to where the fire was when it was reported first and confused for a volcano in 1828. I think that the lower ground elevation at the saddle point means the distance between the free surface and the burning seam was at a minimum. Hence, I infer than the much increased air supply contributed to the ferocity of the burning and the plume of smoke ought to have been majestic. The depth to the seam might have been short enough that the coal walls could be seen glowing red. Lava they thought?. This would be nothing compared to the faint hot gases released now that the fire is again at a hill top and more than 30 m deep.


    Fig 4. Google maps of the reserve showing the approximate track and the current location of the fire at the top of the second hill.

     An interesting observation that I could make during my visit is that after the hilltop, the forward path of the fire, just 20 m away, is on a very steep fall of 100 m down to the bed of a small river. If the coal seam is running just under the river, the fire could reach again massive proportions as in 1828. Or it could be that the coal seam does not continue after the hill top, and that the fire will naturally extinguish itself within my lifetime after more than 6,000 years burning. Either way, what a lucky historical coincidence for me to witness it happening. I will not miss another visit in the next decade.

    The Burning Mountain is just one example. Thousands of underground coalmine fires have been identified around the world, especially in China, India and USA. Elusive, unpredictable and costly, coal fires burn indefinitely while there is fuel, choking the life out of a community and the environment while consuming a valuable energy resource. The associated financial costs run into millions of dollars including the loss of coal, closure of coal mines, damage to the environment and fire-fighting efforts. There are other well-documented cases like when in 1962 an abandoned mine pit in Centralia, Pennsylvania, USA was accidentally lit. Many unsuccessful attempts were made to extinguish it, letting the fire continue to burn until today after more than forty years. Geologist estimate that there is fuel for 250 years more of fire.


    Recommended reading (and viewing) on smoldering fires:
    • Abbott, W.E., 1918. Mt. Wingen and the Wingen Coal Measures. Angus & Robertson, Sydney. http://trove.nla.gov.au/work/21299713
    • Mayer, W. , 2009, Geological observations by the Reverend Charles P. N. Wilton (1795 -1859) in New South Wales and his views on the relationship between religion and science, Geological Society, London, Special Publications 310, p197-209. http://dx.doi.og/10.1144/SP310.20
    • Smouldering, Wikipedia, http://en.wikipedia.org/wiki/Smouldering
    • Smouldering Fires and Natural Fuels, by Guillermo Rein, Chapter 2 in:
      Fire Phenomena in the Earth System – An Interdisciplinary Approach to Fire Science, pp. 15–34, Wiley and Sons, 2013. http://dx.doi.org/10.1002/9781118529539.ch2
    • Stracher, G.B., Prakash, A. & Sokol, E.V. (eds) (2010) Coal and Peat Fires: A Global Perspective, 1st edn; vol. 1: Coal – Geology and Combustion. Elsevier Science
    • Pennsylvania's 50-Year-Old Coal Fire by SciShow. www.youtube.com

    Friday, 13 June 2014

    Forecasting Wildfires and Natural Hazards

    A technology able to rapidly forecast wildfire dynamics would lead to a paradigm shift in the response to emergencies, providing the Fire Service with essential information about the ongoing fire. In this recent paper that we have published [*] in the journal Natural Hazards and Earth System Sciences, we present and explore a novel methodology to forecast wildfire dynamics in wind-driven conditions, using real-time data assimilation and inverse modelling.

    The forecasting algorithm combines Rothermel's rate of spread theory with a perimeter expansion model based on Huygens principle and solves the optimization problem with a tangent linear approach and forward automatic differentiation.


    Its potential is investigated using synthetic data and evaluated in different wildfire scenarios. The results show the capacity of the method to quickly predict the location of the fire front with a positive lead time (ahead of the event) in the order of 10 min for a spatial scale of 100 m.

    The greatest strengths of our method are lightness, speed and flexibility. We specifically tailor the forecast to be efficient and computationally cheap so it can be used in mobile systems for field deployment and operativeness. Thus, we put emphasis on producing a positive lead time and the means to maximise it.

    [*] O.Rios, W. Jahn, G. Rein, Forecasting wind-driven wildfires using an inverse modelling approach, Natural Hazards and Earth System Sciences 14, pp. 1491-1503, 2014. http://dx.doi.org/10.5194/nhess-14-1491-2014 (open access) 

    Tuesday, 8 April 2014

    G3E4O Geoengineering and the Engineers of Gaia

    Earthrise seen by the Apollo 8 crew, 1968. Credit: NASA
    Blog by Nils Roenner and Guillermo Rein, Department of Mechanical Engineering at Imperial College London.


    Because of global concerns on climate change, engineers are called to have a leading role in tackling the problem, and a new discipline is being proposed: Geoengineering (G3E4O(IN)2R).
    The realisation that man has an impact on Earth has led to the idea of the Anthropocene which signifies the current geological epoch, ‘the recent age of man’. Humans are being viewed as a factor and intricate part of nature. This is in agreement with Dr Lovelock’s Gaia hypothesis, introduced in 1979, a revolutionary view of the Earth not as a simple accumulation of systems but as one self-regulating system encompassing everything, including life.
    Sketch of the Earth as system of systems with interdependencies and feedback lines outlined. Adopted from Rial et al. 2004 (10.1023/B:CLIM.0000037493.89489.3f).
    In an article we wrote in 2013, The Engineers of Gaia, by using the concept of Gaia and the Anthropocene as starting points, we argue that the control system view of Earth is a vital part of geoengineering. It is not about one mechanism, it is about the self-regulating system as a whole. But if geoengineering was to apply a forcing too large or at the wrong place, such that positive feedback loops overtake, the results could be drastic and unpredictable. Careful and robust control is required when engineering something as vital as the system Earth, and this argument is often invoked to stop geoengineering proposals. Paraphrasing Prof Henry Petroski, for us, the premise would be that geoengineers welcome all the relevant science they can muster, but cannot wait for complete scientific understanding before acting to save life or create a new planet-saving technology. We also maintain that up until the moment when adequate understanding and models of the system are found only reversible and well controlled geoengineering interventions should be applied on a large scale, in order to prevent uncontrollable feedback being set off or reaching tipping points by accident.

    The term geoeneering has only recently gained traction in the public debate, and its definition still varies according to the source. We think this can be defined as the large-scale anthropogenic intervention into the system Earth in order to adjust planetary mass and heat transfer processes, such that global catastrophes can be mitigated. Geoengineering opens up a broad range of measures with which global climate change can be tackled. No geoengineering approach should be viewed as a single solution to all of the problems associated with climate change. Most likely a combination of approaches will yield long term success. 

    Our article briefly evaluates four promising applications of geoengineering using a set of criteria by which geoengineering proposals can be evaluated in term of feasibility, effectiveness, safety, geointervention, and costs.  These are summarized here:

    Carbon Capture and Storage is a good option for rich countries aiming at reducing its CO2 emissions from power plants. Apart from its high cost, this method is very feasible and effective with low levels of geointervention and risks.

    Biomass Burial is a good option for countries that have suitable and extended land. It is a lower cost approach and can be scaled up to have a larger impact. Low cost, feasibility, effectiveness and low levels of geointervention speak in favour despite some risks, like fire, which need to be managed.

    Iron Fertilisation of oceans is an option for countries with coastal access. The low cost involved and the proven feasibility make this method appealing. But concerns about low effectiveness, high level of geointervention and high risks question the validity of the approach.

    Cool Roofing of Building is a good approach for densely populated areas or countries with high annual level of sunshine. The low cost, risks and level of geointervention of this feasible option are attractive but on the other hand, it has a weak effectiveness and cannot control secondary effects.

    Illustration of the strengths and weaknesses of the proposals under study.
    It can be said for all geoengineering proposals, that due to our incomplete understanding of all feedback and threshold points in the global system of the Earth, the topic has to be approached with great caution. But its potential in helping to solve the great problem of climate change, make the efforts put into research and experiments worthwhile.


    Tuesday, 1 April 2014

    Welcome Francesco to Imperial Haze Lab

    Today was the first day of Francesco Restuccia at Imperial College London as new PhD student in m group. He joins the Imperial Haze Lab in the Department of Mechanical Engineering.

    Francesco is from Italy. He became  a Mechanical Engineer from the University of Edinburgh in 2012, and then obtained an MSc degree from California Institute of Technology in 2014. At Caltech, Francesco studied numerically the problem of accidental ignition of liquid fuel tanks. At Edinburgh, he worked on smart distribution networks and renewable energies. He also spend time conducting experiments at CERN Cryogenics.

    The preliminary title of his thesis is "Computational Study of Porous Reactive Media" and is funded by EPSRC. The aim of the thesis is to provide a better understanding of fundamental smouldering phenomena to aid in the mitigation and prevention of peat and coal fires. This is frontier research at the interface between combustion science and Earth sciences.