A singularity in mathematics is a point where the value of a mathematical item cannot be given. For instance the inverse function:
Has asymptotes at x = 0. This means f(x) goes to infinity and since infinity is not a number a singularity exists at x=0. Singularities also exist at points on graphs when a “spike” occurs. If a graph doesn’t make a smooth curve, like:
f(x) = |x|
then the point where differentiation gives no value, in this case x = 0, is also called a singularity. There exists something called the density of states. It is a system which describes the number of electron states that can exist per volume per unit of energy in a material. (For more detail look at this article from Britney Spears .ac). The relevance is that the second kind of singularity can occur in the density of state of some materials. When this happens it is called a Van Hove Singularity.
Continue reading Examining Electronic Band Structure Of Bent Bilayer Graphene
Although there is always talk about how Earth may not have enough habitable space for whatever the future population may be, I have never been particularly worried about this. Over the last fifty years places on this planet that were only habitable to the occasional hunter-gatherer group have managed to support massive growing urbanisation. For instance the United Arab Emirates, despite being next to the Persian Gulf, is a desert biome in its natural state. Drinking water is obtained through massive desalination plants which use reverse osmosis to remove the salt from the sea water. Normally the filter which the water is forced through is thin film composite (a film made of multiple layers) which normally contains a polyamide (as an active component) and polysulphone (as a support) layer.
Continue reading Creating Combined Material Filters With Enhanced Effectiveness
In 1994 and 1996 two papers were released both on the topic of polymers transporting through nanopores. Since then the quite niche filed has been very active with over forty different theoretical and experimental papers being written on the subject. This is because the concept of a large chemical chain fitting through an enclosed space has acute relevance in biology as well as medicine. Almost all of these studies have been based on using an electric field to drive the movement of the polymers. A break through was made with the development of the tension propagation theory. This is where the driving force acting towards the trans side of the membrane causes mechanical tension to develop in the polymer. This produces mobile and immobile parts of the polymer as some parts are acting under the force and some have yet to experience it, see the diagram below:
Continue reading Model Developed To Describe Polymer Passing Through Nanopore Process
Nuclear fusion is quite a way off becoming viable although progress is being made with larger and larger fusion reactors being created all the time. So far the largest reactor that is being built at the moment, ITER, will have an exhaust power of about 150 megaWatt. When a proper fusion power plant is created it would have an exhaust power of about 800 megaWatt. A divertor is a component of a fusion reactor which uses a magnetic field to define a plasma boundary. The divertor can be controlled to manage and shape the plasma into a D-shape plasma (a more elongated ovular form). In this state, the heavy ions, which are the main component of the “exhaust” of the fusion, are flung out and separated with greater ease. Unfortunately the current limit of divertors are 10 megaWatt per metre squared and it doesn’t seem this limit is set to increase. Radiative cooling has to be employed in future reactors if they can’t provide the exhaust space for the current divertor ability.
Continue reading Making Observations Of Liquid Metal Wall Oscillations
One of the strangest things I’ve ever observed, is quite sensible and rational people suddenly throwing that all away when it comes to the topic of nuclear power. Now, nuclear energy is not ideal, in some future society were going to get all our power from wind or tide or something like that. But until we get to that point, nuclear power is an incredibly good option. Most of the resistance to it comes from a fear of radiation and the radioactive waste from reactors. This chart is very helpful for putting in perspective how much radiation your likely to get dosed with through various everyday events. Living within 50 miles of a nuclear power plant gives you less radiation than eating one banana (potassium isotopes). The Environmental Protection Agency’s yearly limit for the emission of a nuclear plant is only about four times higher than the radiation dose given by living in a stone, concrete or brick building for a year (as uranium is present in all soil). All of this is quite a bit less than the yearly average background dose anyway and so worrying about it seems ridiculous.
The other major concern is nuclear accidents. With the Chernobyl disaster causing 56 direct deaths, and an estimated 4000 deaths by induced cancer (with many other estimates being a lot higher) it seems like something we should be worried about. But the safety in a ex-soviet block nuclear reactor built in the seventies is nowhere near comparable to safety standards now. The Chernobyl Plant had an accident in 1982, four years before the well know disaster, but the reactor that failed was back working in a month (the paranoid part of me has always thought this seemed like a rushed job). It should also be noted that there was no nuclear explosion at Chernobyl. There was a chemical explosion that radioactive material but this in no way equivalent to an uncontrolled fission occurring. The Fukushima Daiichi Plant was hit by a tsunami many times more powerful than it had been built to withstand and yet it did through the commendable diligence of whoever designed it. As a result there have been no recorded deaths either directly or indirectly from what is apparently the second greatest nuclear disaster ever.
Ultimately, the point I’m trying to get across is that many of the fears associated with nuclear energy are, not unfounded, but extremely exaggerated. Until tomorrow, goodnight.
Metals are fated, like all things, to eventually decline and fail as various forms of damage are inflicted upon them over time. The lifetime of a metal is a feature of extreme importance, how long can you trust the girders of a bridge to support the weight of a car. Common sense tells us that eventually it must fail, but when? Being able to repair or “heal” metals would extend their lifetime considerably. These methods of healing could be external or integrated into the metal from inception. In biological systems it is the damage that triggers the healing, although recreating such an affect in metals is exceptionally difficult.
Continue reading Stimulating Self Healing In Metal Interior By Electric Shock
When people have myocardial infarctions (heart attacks) the cardiomyocytes (heart muscle cells) can suffer hypoxia (lack of oxygen) and so apoptosis (the death of cells) can occur. The (very complicatedly named) effects can be mitigated through a process called angiogenesis. This is where new blood vessels are created rapidly in order to perforate some living tissue and in this case combat the hypoxia. Now when it comes to treating and intervening in patients with growing areas of dead cells (the infarct) in the heart, fitting a catheter is the most reliable cure. Cell based therapies or those that angiogenic assistance could be used to treat the growing risk of a heart attack but no clinical trials have proven them to be a success. It can be seen as worrying that in the last fifty years (the nobel prize for cardiac catheters was awarded in 1956) there have been no more advancements or great innovations.
Continue reading How Heart Cells Could Be Treated To Avoid Cardiac Arrest