Pyrolysis – Making Plastic Fantastic

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Naomi Brown

Since the initial use of plastics in the 50s, over 8.3 billion metric tonnes of plastic have been created – equivalent to the weight of 80 million blue whales!  Of this vast quantity, it is believed that 60% has been discarded in landfill or elsewhere in the environment. Plastic pollution constitutes 90% of waste on the ocean’s surface and has been documented in the bodies of 44% of seabird species.  As none of the mass produced plastics biodegrade readily, we need to consider alternative ways to deal with this waste. Pyrolysis of plastics has been touted as a technology that could solve the problem by breaking down plastic and using it for energy.  

The word pyrolysis comes from the Greek ‘pyro’ meaning heat and ‘lysis’ meaning breaking down. Plastic is made up of long chain molecules called polymers. These chains are degraded by heat and pressure in the absence of oxygen. This forms increasingly smaller molecules.  

The waste plastic is cleaned then placed in a high pressure reactor and heated up to 400 – 500 °C, causing the atoms within the long polymers chains to vibrate to such an extent that the bonds between them break. The plastic does not burn but is melted to a chewing gum consistency. Further heating vapourises it to form a gaseous mixture of different sized molecules, which are separated by a process called fractional distillation.

There are 3 products of plastic pyrolysis: carbon black, liquid oil and hydrocarbon gas. The carbon black can be used in the place of coal or as raw material for making carbon nanotubes. The oil is used to power electricity generators or as a raw material in making petrochemicals, such as lubricants used in manufacturing. The hydrocarbon gas produced is used in the pyrolysis process itself, in order to create the high temperatures required.

Aside from the reduction in waste going to landfill and plastic pollution, there are some other major benefits to using pyrolysis. Only 80% of plastic produced can be physically recycled (the type of recycling where plastic waste is broken down into small granules which are used to manufacture new materials).  In contrast, pyrolysis can be used to break down all plastics.

The process is environmentally friendly: a vacuumed chamber is used, which means toxins are not emitted into the atmosphere, plus the gas is collected and used to power the plant, saving energy for the whole process.

There are also economic benefits to using pyrolysis. Primarily, it is cheaper than disposal in landfill. Implementing the technology is simple and inexpensive and the construction of a pyrolysis plant can be relatively fast. There is the potential that with the introduction of new plants there will be the creation of many new jobs.

A few companies have tried to commercialise pyrolysis in the United Kingdom. One example was Cynar, a plastics-to-fuel company based in London. They constructed their first pyrolysis plant, in Ireland in 2008, with a capacity 20 tonnes per day.   The company set about building further facilities, through partnership deals in Spain and the UK, however the company went into liquidation before completion.  Another company, called Enval, has utilised microwave pyrolysis to recycle plastic aluminium laminates (which cannot be recycled any other way). They have a plant based in Huntingdon, Cambridgeshire, with the ability to process 2000 tonnes per year.  However, no councils are using this type of recycling at the moment. This is because councils have existing contracts with waste management service providers. Hopefully, there will be an increase in the use of pyrolysis as contracts come up for renewal.

Dyslexia: In the eye of the Beholder?

Dyslexia Word Cloud

Bethany Firmin

Dyslexia is a specific learning difficulty (SpLD) affecting between 5-10% of people. The disorder is characterised by difficulties in phonological awareness (this refers to the ability to focus on and manipulate individual sounds in spoken words), verbal memory and verbal processing speed.

As well as difficulties with spelling and reading, there are a broad range of other symptoms – this can include concentration issues, trouble understanding certain jokes/expressions and difficulties with time management. Dyslexia is a broad spectrum, with some individuals experiencing some of the associated difficulties but not others, and with varying levels of severity. While some may have mild dyslexia, which can (personally, I was only diagnosed in my first year of university) be managed, others may always struggle significantly with reading and spelling. Intelligence is not affected.

For someone to be diagnosed with dyslexia, diagnostic tests are carried out, the content of which varies depending on the age of the individual. While these tests are very useful in giving information about an individual’s specific strengths and weaknesses, they can be very time-consuming.

Currently, there is no cure for dyslexia, but there are many strategies to help people, such as alternative exam arrangements and extra tutoring. With adequate support, many people with dyslexia go on to be very successful in life. The importance of early intervention is emphasised.

Dyslexia is widely believed to be a neurological problem, but a recent study suggests they may have found a possible cause of dyslexia – not in the brain, but the eyes!

Photoreceptors in the eye

In the eye, there are two types of photoreceptor (structures that respond to light) – the rod and cone cells. Rod cells, the more plentiful (around 120 million), respond to low levels of light but do not detect colour, which allows you to see in the dark. There is only one type of rod cell, and they are absent from the fovea (the region of the retina responsible for the highest visual acuity) but concentrated elsewhere. Cone cells (6-7 million) are only activated at higher concentrations of light, but detect colour. There are three types of cone cell – blue, red and green. There is a ‘blind spot’ in the fovea of about 0.1-0.15 millimetres, in which there are no blue cone cells.

Eye Dominance and Dyslexia

Similarly to the way in which most people have a dominant hand (apart from those who are ambidextrous), most people have a dominant eye. Both eyes record slightly different versions of the same image, so the brain decides which one is likely to be the most accurate. Signals from this dominant can override signals from the other. Lots more people are right-eyed than left.

This study investigated the presence or absence of eye dominance in 30 non-dyslexic students and 30 dyslexic students, using a method called the afterimage test. For the non-dyslexic participants, 19 were right-eye dominant and 11 were left-eye dominant – therefore, all had a dominant eye. On the other hand, 27/30 of the dyslexic participants had no dominant eye.

Furthermore, there were correlations between lack of eye dominant and apparent physical differences in eye. In the dominant eye, the shape of the blind spot is circular, while the shape in the non-dominant eye is elliptical. In the dyslexic participants with no eye dominance, however, the shape was circular in both eyes. For one of these participants, five family members who also had dyslexia were studied – there was no asymmetry in the arrangement of cone cells, as well as no eye dominance. This suggests a possible genetic cause of dyslexia, and could lead to new diagnostic strategies for dyslexia

Lack of asymmetry would mean the brain has to process two slightly different ‘mirror images’, which researchers believe would confuse the brain. Perhaps this could explain why dyslexic people commonly make ‘mirror image errors’ – for example, mistaking ‘b’ and ‘d’, or ‘3’ and ‘E’ – and often get confused between left and right.

So, what else does this study mean for dyslexic people? Firstly, lack of afterimage dominance could lead to a potential new, quicker way to diagnose the condition. In addition, researchers were able to use an LED lamp to “cancel” one of the images in the brains of the dyslexic participants, which reduced reading difficulty. Some participants referred to this as the “magic lamp”.

Considerations & Limitations

While this study seems very promising, it is important to remember that only 30 dyslexic participants were studied – this sample size is too small to draw any absolute conclusions. Also, all participants were students, so these would not have been representative of the whole dyslexic population.

A further problem is that the study cannot establish cause-effect relationships. It cannot be said whether the visual differences are the trigger of dyslexia, or simply a consequence.

As well as that, the findings from the study may explain some people’s dyslexia symptoms, but may not necessarily explain the symptoms of other people. As mentioned before, dyslexia has many symptoms and manifestations, which this study does not necessarily explain. For me, I don’t experience ‘mirror image’ distortions when reading, but the words sometimes start to go wobbly after I’ve been reading for a while. There are a range of other distortions experienced by other dyslexic people too, such size distortions of letters/words or gaps between words appearing narrower/wider.

In conclusion, while the study seems promising, significantly more work is needed before any proper conclusions about the cause of dyslexia can be drawn.

Sheffield’s Giant Battery

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Kirsty Broughton

A major step towards greener energy in the UK was taken last month with the opening of an industrial-scale ‘mega-battery’ site owned by E.ON in Sheffield.

The Sheffield site located in Blackburn Meadows is being hailed as the first of its kind in the UK. It has the capacity to store or release 10MW of energy – the equivalent of half a million phone batteries, and is contained in four 40 foot long shipping containers. The batteries are from the next generation of battery energy storage, and can respond in less than a second to changes in energy output – ten times faster than previous models.

Such promising technology has naturally lead to further investments, and the Sheffield site will soon be dwarfed by significantly larger plants. Centrica (the owner of British Gas) and EDF Energy are both in the process of creating 49MW facilities in Cumbria and Nottinghamshire respectively.

When more energy is being put out into the national grid than is being used by consumers, the batteries will take in the excess power and store it. Then, during periods when consumers are using more energy than the grid can provide, the batteries can release this excess energy into the grid, to ensure that everyone has access to power.

This is especially important considering that the UK energy mix is containing an ever-increasing proportion of intermittent sources, such as wind and solar power. June this year saw 70% of the electricity produced from nuclear, wind and solar sources. For the government to hit legally-binding carbon-cutting targets this needs to be the standard for electricity production, but storage is likely to be necessary to balance the intermittency of renewable supplies.

To meet these targets the government introduced a ‘capacity market’ – a subsidy scheme integral to the shake-up of the electricity market. It is designed to ensure energy security particularly during times of high demand, such as the winter months. The scheme has a pot containing £65.9 million, which it will divide between energy suppliers than can guarantee a constant energy supply. It may sound surprising that in the age of austerity the government that is ever-interested in penny pinching is wanting to hand out money. However, it is estimated that the Sheffield site alone could save £200 million over the next four years by increasing energy efficiency. This certainly makes the £3.89 million awarded to E.ON a worthy investment.

E.ON has seen share prices in Germany dramatically fall as it is undercut by abundant, cheaper renewable energy from other suppliers. Germany is often hailed as world leader in renewable energy production, and during a weekend in May of this year 85% of energy production was from renewable sources. E.ON in the UK was following down the same path, as in recent years UK profits have stagnated, and trade has fallen by up to 9%. It was only in March of this year that profits began to pick up again, due to the company shifting away from fossil-fuels and towards green energy production. The battery site in Sheffield is an excellent next step in this major shift.

Why do we Procrastinate?

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Emily Farrell

Everyone procrastinates. No one wants to write that essay, or clean the bathroom. If it’s not food, sex or sleep, your body is just not interested. Sure, in the long run you might need to write that essay, to get that degree, to get that job, to earn money to buy food to survive. But your body doesn’t understand, or care, about that. Your body is a thing made in simpler times. It is built for when survival entailed going off to pick some plants to eat, some reproducing and maybe a bit of sleep afterwards. But modern, western lifestyles are a horrible mismatch for this way of living. Imagine giving a caveman a long, boring, task to do such as moving numbers from one column to another (maybe with sticks, it could take a while to explain the concept of computers). Why should he do it? He gets no food from it. He gets no joy from it. Doing this task does not make him any more attractive to cavewomen who might then want to have his babies. It takes a reasonable amount of energy that is better spent in other labours. So why should he do it? To him, the answer is he shouldn’t. And this is the thought process your brain goes through when faced with a task. While the conscious parts of your brain know the real reason for the task, your ancient parts of the brain, which we share with our ancestors and other animals, do not.

Think about it. How do you procrastinate? Making a snack? (means you won’t starve to death) Taking a nap? (means you won’t be too tired to see the tiger of death headed your way) Talking to friends? (maintaining social bonds which one day might lead to you making tiny replicas of yourself vis someone else’s genitals) Watching cat videos? (evolution can’t explain the internet, but taking joy from something which takes away no resources you may have gained from the other tasks means your body agrees to it).

Cleaning your own room is therapeutic and has actually been shown to improve your mood while doing it and afterwards when you’re in your nice clean room. But when it comes to the gross shared bathroom every uni student has encountered, you put it off for longer. You procrastinate away from it. This is because you gain no real benefit from it. It’s not dirty enough to give you diseases (yet), and you don’t spend enough time in it for it to benefit your mental health. If you can’t see an immediate advantage, you won’t do it.

Procrastination is all about cost and benefit and finding the balance between the two. If the immediate payout does not equal or outweigh the energy expenditure required to perform the task, then the inclination to do it will disappear.

Think about this the next time you put something off and do something else instead. Would what you are putting off benefit a caveman? Would he benefit by doing what you are doing now? But don’t listen to your inner caveman. Listen to your inner modern human who wants that essay done, because they know that you really need to do it. Don’t let them in only at the last second to write it. Go and do something productive! Go!

Using Cancer to treat Diabetes? Sort of…

Vanessa Kam

Tumour.  The word immediately summons negative connotations, embedded in the general fear surrounding cancer and impounded by the Daily Mail’s endless crusade to classify everything into cancer causes or cures.

While ‘tumour’ is often used as a synonym for ‘cancer’, in science, the two are not quite the same.  ‘Tumour’ is derived from the Latin word for ‘swelling’, and originally referred to any swelling, like a pooling of fluid in inflammation.  Nowadays it is used to refer to ‘neoplasms’ which form a mass, an abnormal growth of cells appearing bigger in size.  These masses can be benign, sticking to one location and easier to treat, or malignant, invading into other tissues and spreading around the body.  Cancer, derived from the Latin word for crab, refers to the malignant tumours, which extend out from their original site like a crab’s legs from its body.

 

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(Cancer Cells:  Image source: National Cancer Institute)

Now that it’s clear benign tumours are not cancerous, we move on to a diabetes discovery, lest getting tied down by etymology.

In a study published in October, researchers at the Icahn School of Medicine at Mount Sinai, New York, harnessed critical information from the genomes and expression patterns of insulinoma cells.

Insulinomas are rare, small, benign tumours of pancreatic beta cells.  The pancreas is a pivotal organ in regulating blood sugar, and its beta cells secrete insulin to capture excess glucose from the bloodstream for storage.

In diabetes, beta cells are either destroyed by the patient’s own immune system (type I) or cease to function, with type II diabetes seeing a reduction in working beta cell numbers, often alongside insulin resistance.  Much work has been invested into inducing beta cells from stem cells to transplant into patients with type I diabetes, effectively replacing the destroyed cells, but what about inducing beta cells to regenerate in situ?

This is notoriously difficult, in part due to the normal development of beta cells.  Beta cell proliferation occurs shortly after birth, continues for about a year, then rapidly declines in early childhood.  In adults, the increase in beta cells is virtually zero, bad news for diabetics.  Even at its highest rate, beta cell proliferation is relatively low, with about 2% of cells dividing versus up to 50% in other cell types.  With normal proliferation rates so low in later life, there’s a particularly high barrier to promoting regeneration in adult beta cells.

This is where insulinoma comes in.  In insulinomas, beta cells proliferate.  While this generates tumours which overproduce insulin, causing patients to display symptoms of low blood sugar, identifying the mechanisms by which insulinoma cells overcome division dormancy can be applied therapeutically to diabetics, re-expanding their beta cell populations.

In fact many cancers are undergoing genomic scrutiny under various projects, including the Cancer Genome Atlas and the International Cancer Genome Consortium.  But seeing as insulinoma has a low incidence rate of two in every one million people worldwide and is largely benign—only 10% is cancerous,—insulinoma slipped through the net.

Until now.  Wang and his team at Icahn conducted whole exome sequencing and RNA sequencing on 38 benign human insulinoma samples, analysing the DNA sequence for all the protein-coding genes (exons) in the cells and the transcriptome, the variable, actively expressed portion of exons in those particular cells at that specific point in time, comparing them to normal beta cells.

They found insulinomas to display mutations and differing expression of epigenetic modifying genes—genes coding for proteins which alter the expression of other genes without changing their DNA sequence—and their targets.

One such example is a new potential drug target KDM6A.  KDM6A supports the cell cycle inhibitor CDK1NC, a protein only expressed in pancreatic beta cells and prompts their inability to divide.  CDK1NC is reduced in insulinoma, and allows beta cell proliferation when turned off.

KDM6A was mutated in several insulinoma samples in this study, prompting the team to interfere with it by inhibition using both a drug and a virus.  This resulted in lower levels of CDK1NC, which will allow beta cells to re-enter the cell cycle and proliferate, exciting news for diabetes therapy.  Future work screening for molecules which inhibit KDM6A may identify drugs promoting beta cell regeneration.

In fact, this study reaffirmed the presence of targets of a novel drug another team at Mount Sinai identified.  In 2015, after screening through 100,000 compounds, only one, harmine, was found to drive human beta cell replication in culture.  This was unheard of, with all previous attempts seeing beta cells resist pushes to multiply.

Harmine is derived from the plant harmal, which due to its psychoactive properties, is used in many spiritual rituals, hung around to protect from the ‘evil eye’ in Turkey, for example.  When used to treat mice mimicking human diabetes, harmine tripled beta cell numbers and improved blood sugar control, and is now under early development for diabetes treatment.

However even with harmine, the induced proliferation rates of beta cells are modest.  With new information about beta cell replication gathered from insulinomas, more novel drug targets can be identified and promising compounds highlighted.  This goes to show that studying rare diseases like insulinoma can bring about medical advances for the masses, with beta cell regeneration therapy now an increasing reality for the millions of diabetics worldwide.

Dreams of Mars

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Sam Jenkins

In 2002, Elon Musk founded SpaceX, with the view of revolutionising space technology and the ultimate goal of making it possible for mankind to live on planets other than Earth. This came just a year after Musk detailed Mars Oasis, his plan designed to build public excitement at the idea of eventually walking on Mars, as he was disappointed with NASA’s lack of plans for sending any manned mission there. The idea was that a lander would be sent to the surface of the red planet, carrying a small greenhouse. On landing, seeds in dehydrated nutrient gels would be activated. The life and death of the plants they grew would give an insight into the challenges of sustaining life on Mars. However, Musk soon realised that the current level of technology was the main obstacle in seeing his dream succeed.

As you’d probably expect, getting to Mars is difficult. NASA has so far had six robotic landers successfully touch down on the surface, and although this is impressive, robotic missions are far easier than manned missions. This is because the manned missions not only have to carry the crew and supplies but also, crucially, fuel for the trip back home. For this reason, future manned missions will likely dock with a spacecraft in orbit around the planet, where fuel and supplies can be kept, rather than heading straight for the surface. While the journey to Mars would generally take about 300 days, much of the fuel on-board will get used at the very beginning and end of the trip. Firstly, the ship must be accelerated to roughly 25,000 miles per hour, to escape the gravitational pull of the Earth. Upon arrival at Mars, the ship must then decelerate, so it can be captured into circular orbit around the planet.

Traditionally firing booster rockets do this backwards, but to save on the amount of fuel required, scientists are employing new techniques. The first, known as aerobraking, has already been employed successfully in missions. This involves getting the ship into an orbit via reverse firing of rockets, and then using the drag caused by passing through the upper atmosphere of the planet to slow the ship, and achieve the desired circular orbit. The second, which has never been tried before, is known as aerocapture. Instead of using rockets to slow the ship down it goes straight into the atmosphere, at a slightly lower altitude than for aerobraking, and the drag from the atmosphere causes the ship to be captured straight into a circular orbit. This means a lot less fuel must be carried on the journey. Unfortunately, using this method of braking causes the kinetic energy of the rocket to be transformed into heat, requiring more thermal protection for the ship. Overall though, this weighs less than the fuel that would otherwise be needed, and any weight saving is an advantage when it comes to space travel. Sadly, funding cuts and tight budgets are causing NASAs plans to be slowed dramatically, and as such collaboration with other agencies such as SpaceX will be paramount to man’s ability to reach the red planet.

15 years since its founding, SpaceX has undoubtedly made large leaps in terms of their technology, frequently making headlines for vertical landings of rockets. For travel to Mars, SpaceX plans to employ their recently revised BFR rocket design, capable of carrying a payload along with an eight-story tall living space. Musk hopes that these will begin construction next year, with the potential for two carrying just cargo to launch in 2022. They would then aim to follow this two years later, with two carrying cargo and two carrying crew. Once there, the missions would aim to find water and establish a propellant plant, for running around trips between the Earth and Mars.

While some see these dates as ambitious, Musk describes them as “aspirational”. Regardless of whether these dates slip or not, manned missions to Mars are swiftly becoming a real possibility, and that is something we should all be very excited about.

Elon Musk’s Solar Panels – the Future of Green Technology?

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Megan Hoyle

It has been nearly two months since Hurricane Maria, a category 4 hurricane, devastated the electrical grid of the Caribbean island of Puerto Rico. Over 80% of the island is left without power. The coal and oil plants in the south-east of the island suffered some of the worst damage from the storm. The island is beginning a long re-building process on not only these, but the already-dilapidated power lines. Citizens are currently reliant on back-up diesel-powered generators, but schools remain shut, businesses are closed, and tens of thousands are fleeing the island.

The Puerto Rico Electric Power Authority (PREPA) – with complete responsibility and monopoly over the generation, transportation, and distribution of electric power on the island – was forced to declare bankruptcy earlier this year, after operating on a deficit of around $354 million, attributing around 58% of its expenditure to the purchase of fuel – predominantly oil. Despite tens of millions of dollars being spent by governments on projects planning to reduce the island’s dependency on oil by the implementation of solar and natural gas projects, nothing has happened, and the island can attribute only 3% of its energy to renewables.

While relief staff struggles to restore the outdated, tumble-down grid, the opportunity to revolutionise Puerto Rico’s energy sector has captured the attention of politicians and environmentalists alike, including Tesla founder Elon Musk. Musk has been in discussions with the Puerto Rican Governor regarding his solar-powered ‘microgrid’ technology, which has been successfully implemented on some American Samoan islands already. Put simply, the microgrids operate by capturing solar energy in panels, then storing and converting the energy into electricity via ‘powerpacks’. The systems can operate independently of the main power grid, making them less vulnerable to widespread power outages.

Microgrid in Ta’u, American Samoa

In November 2016, a subsidiary of Tesla completed an $8 million installation of a microgrid on the island of Ta’u, American Samoa. The microgrid, comprised of 5328 solar panels and 60 powerpacks on seven acres of land, saw the island transition from 100% diesel-fuelled power to completely solar-powered. Capable of providing 1.41 MW of electricity, it can apparently recharge to full capacity within seven hours, and can provide power to the island’s 600 inhabitants for three days with no sunlight.

The installation of the microgrid will offset the consumption of around 110 000 gallons of oil a year, not taking into account the fossil fuels involved in the production and transportation. While this transition to renewable energy is highly advantageous in terms of greenhouse gas emission and fossil fuel consumption, the problem with solar energy is that it is inherently intermittent and unpredictable, and while it is a feasible to power the island’s small population, is it truly feasible in the much larger, more densely populated island of Puerto Rico? How true is Musk’s claim that there is no ‘scalability limit’ for the technology?

Are Solar-Powered Microgrids the Future of Green Energy Production?

The island of Ta’u is a fantastic example of a successful transition to renewable energy, severely reducing the use of fossil fuels and preventing the production of 1100 tonnes of carbon dioxide emissions per year. While this technology is ideal for the sparsely populated island of Ta’u, the power consumption per capita and the much larger population of Puerto Rico pose a challenge to the microgrid technology. Based on a power consumption of 606 W per person and a population of 3.41 million, Puerto Rico’s power consumption equates to around 2.07 GW, approximately 1500 times the consumption of the small island of Ta’u.

This is not to say that Puerto Rico does not have an ideal climate for the utilisation of solar power, with a UV index of around 7 in the winter and exceeding 10 throughout summer. Comparatively, the UK rarely reaches an index of around 7 at the height of summer.

In the wake of storm Maria, Puerto Rico has been presented with an opportunity to pioneer the use of solar energy on a national scale, following in the footsteps of other nations such as Costa Rica who have transitioned to predominantly renewable-based energy. Although there are obvious issues regarding consistency associated with solar-power and the challenges we face in the development of highly efficient solar panels, implementation of microgrids in a network of renewable-based energy production could help Puerto Rico make a transition from almost wholly fossil-powered to a revolutionary renewable energy grid. Microgrids in tandem with renewable energy sources, including solar panels, could potentially shape the future of national power networks and mitigate the effects of extreme-weather damage – preventing communities from suffering without power for months. While the reconstruction of the Puerto Rican power grid faces financial and technical challenges, the project offers a unique opportunity to showcase the benefits the transition to renewable energy could have on a national scale.