Waves

Waves are everywhere and most of the information we receive is from waves. These waves can be present in two forms mechanical or electromagnetic:

Mechanical waves are waves that progress through a substance and the particles of that substance vibrate in a certain way and pass that vibration to neighboring particles.

Electromagnetic waves are vibrating electric and magnetic fields that progress that progress through space without the need for a substance. The vibrating electric field generates another vibrating electric field and so on.

One of the most know functionality of waves is its use in music and TV. Some uses are more inconspicuous for example; cooking with waves, talking to others and see things all because of waves. Waves transfer energy in different forms, some are very useful, while others can be quite dangerous.

The sound-proof room

Since sound can not travel in a vacuum, acoustic engineers can design soundproof barriers or rooms. If you remove the air between two walls you will be able to greatly reduce the amount of sound that is transmitted. You can also place sound absorbing materials, like the insulation in your home, between the walls to cut down on the transmission of sound waves.

Advertisements

Why Particle Physics matters

Particle physics is about the fundamental properties of matter, radiation and energy. Modern particle physics is innovative and shaped mainstream society in the discoveries and theoretical developments that has transformed the way we live. Many advances in several sciences have been predicated on the discovery of the electron and quantum theory.

Here are some benefits to society that have stemmed from Particle physics:

Cancer therapy: In medicine the theory has been implemented in accelerators. These accelerators produce x-rays, protons, neutrons or heavy ions for the diagnosis and treatment of disease. The NIU Institute for neutron therapy uses a beam of neutrons to treat cancer patients.

Monitoring Nuclear Waste nonproliferation: Homeland security has implemented particle physics into monitoring technology. The use of uranium and plutonium, can be used as they emit different kinds of particles, a particle detector can be used to monitor and analyse the contents of the nuclear reactor core.

Power Transmission: In industry cables made of superconducting material can carry far more electricity than conventional cables with minimal power losses. Particle physics research will enable the industry to advance and offer power to populated areas where copper transmission lines are near their capacity.

The Internet: Particle physics has developed the internet to share information quickly and effectively. The internet has profoundly affected the global economy and societal interactions.

Light sources: Particle physics researchers have used powerful x-ray beams of synchroton light sources to create the brightest light on earth. These luminous sources provide tools for applications in protein structure analysis, pharmaceutical research, material science and restoration of works of art.

Young’s Modulus

As I have noted earlier the young’s modulus of a graph is the straight line that obey’s Hooke’s law.

Here are some quick uses of Young’s Modulus:

Building in earthquake zones: Comparing the stretch-ability of reinforcement diagonal cables to the stability required by masonry or concrete existing structures to prevent cracking in predicted strength earthquake tremors. 

Medical engineering: Determining weight/ force limits on temporary-glued-in artificial joints, before bone growth makes much stronger bonding to the stub-mounts. 

Aeroplanes: Calculating an overall ruggedness model of fold-able wing-mounts on aircraft deployed to carrier ships.

Here is a video relating to my previous post on yield strength, it also applies young’s modulus:

How to separate alloys?

Since in class we’re studying density, I wondered if I could relate this topic to this question. However my researching skills haven’t really given me any hope in finding a valid answer. However, I have tried to make this post as relevant as possible.

Firstly, separation of any material could either be done with a physical or chemical technique. This can theoretically also be done when separating alloys into their constituent elements.

Physical techniques: To separate the alloy you could try to use atomic vapour laser separation which means separating a desired isotope of a chemical element from the remaining isotopes. Mass spectroscopy could also be used this is when a sample is ionised and are sorted and separated by mass and charge.

Chemical techniques: You could convert the alloy to some chemical form, precipitating each species (element) and then processing them back to metal form. This is how ores are processed. It could also be useful to try an electro-chemical process.

However the fact is, separating an alloy into its constituent elements requires a lot of energy which means it would be a very expensive process to carry out.

Referring back to density; density measurements are a good way to identify unknown substances. If we compare the measurements we found in an alloy we could then compare the densities to known substances. For example if a density of 2700 kg/m³, we know that it contains aluminium.

Another method I researched seems rather experimental, however I thought it was worthwhile to include as referred to using a metal density to aid separation. It also describes separating alloy mixtures rather than separating mixtures of metals in alloys.

The method described separating a mixture of flat metal alloy particles, although particles of one alloy have to be smaller and less conductive than the particles of the other. This scrap mixture can be thermally preheated and then crushed into relatively flat particles, for example if we had a mixture of aluminum-lithium alloy and wrought aluminum alloys then you would fragment the aluminum-lithium alloy into smaller particles making sure to fragment them smaller than the other wrought alloy. You could then separate them physically based on differences in particle size, density and electric conductivity.This could be done by an eddy current separator or a dense media separator.

What’s the point of Hooke’s Law?

Well I didn’t personally know Mr Hooke, but I can tell you there must have been a good reason for him investigating the elasticity of springs. Nowadays though, it is commonly used by material scientists and engineers when selecting materials for structures.

A stress-strain graph; the linear region is called the Young's modulus.

A stress-strain graph; the linear region is called the Young’s modulus of elasticity.

Civil engineers like to study these graphs to increase the yield strength of materials. The yield strength relates to the yield point of a material, the point where the amount of permanent deformation occurs by an increase in extension.The yield strength is the stress where this is produced on the graph. Civil engineers increase yield strength by using strain hardening which is when you use permanent deformation to increase the strength of the material (usually a metal). Basically, you add a load which provides a certain amount of strain to a material and then remove it so it can return to zero stress. This can be done several times, each time plotting a line on a graph. In the end you will notice that after reloading, the elastic limit has increased, in turn the yield strength will be higher than originally. The material will therefore be stronger, although less ductile.

You can see this could be quite useful; hooke’s law provides us with information about elasticity, tension and strength of materials. As long as we plot a graph we are allowed an insight into relationship of stress and strain of all materials so we can chose the right material, suitable for the right job.

Aircraft for instance need a material that produces minimal flexibility and also be light and strong. Aircraft are widely made of aluminum because of its lightness and strength. To increase the strength and reduce flexibility of the material to keep the aircraft’s stiff streamlined shape, aluminum can be strain hardened, made possible by of course, Hooke’s law.

Why is the density of an object important?

About 18 months ago my family and I were discussing holiday options. Many of us, liked the idea of experiencing a hot country or maybe a foreign tropical land, of course something much different then the bustle of London where we live. Unfortunately we were unable to go on holiday that year, but It’s interesting to think about what transport we would have taken. Obviously in this day and age we have a lot of options to choose from. The advancements in modern engineering have allowed us to travel much quicker, easier and safer than ever before. I expect these engineers must be very stringent in the design calculations of these transport machines. If we had traveled by boat, I expect they must have had to carefully calculate the volume and weight distribution to ensure the ship floated, this can be applied to planes also as they must be able to fly correctly. For an object to float it must be less dense than the liquid it is sitting in. This means that density must be critical during design, as engineers need to account for how much space must be allotted for the weight of the object. The boat will only float if it has a greater ratio of empty space to mass, than the fluid. When engineers design ships they know that it will be sailing in water so it must have a density of less than 1.0 g/cm(the density of water), or it will sink. Ships are very heavy but because they have a large volume, the density of the ship decreases less than the density of water allowing it to float. This tells us that the equation ρ = m / V  is very important. Engineers use it to reduce the density of ships for buoyancy; using it we know that as volume increases density increases for the same mass. This tells us that all engineers have to do is increase the volume of the ship to allow it to float, of course reducing the mass could provide the same effect but these ships are made of steel which could present more of a challenge!