Month: February 2017

Crystals

Crystals

02/19/17

“What is a crystal?”
No other material has captivated the imagination of humanity more than crystals. These otherworldly structures have been used for all forms of practices, ranging from pagan rituals to pseudoscientific medical therapies. However, as scientific thinkers, we must not be satisfied with primordial definitions and must analyze what these objects are in their true nature. If one were to shrink down to the size of a molecule and explore the inner fabric of a crystal, then they would find an entire world of atoms fashioned in patterned arrangements. And this is exactly what constitutes a crystal, a solid with a patterned arrangement of atoms! Crystals tend to form when liquids cool and harden, since when the atoms cool they tend to gather together in an ordered manner to form a crystal lattice. Crystals have no “special magical powers” and are as bounded to the laws of nature and you and me.

Crystal defects

Crystal defects

02/18/17

“How do we classify imperfections in crystals?”

Ideal crystals never exist. For every material arrangement out there, there exists some form of a defect within its structure. Specifically, there will be some form of irregularity through its patterned nature called a crystal defect.These defects can be classified into three distinct types: Point defects (when a single atom in the crystalline lattice is placed out of order), Linear defects (when atom groups are found to be erroneous), and planar defects (two-dimensional errors which include grain boundaries and other mishaps that occur between boundaries in a material). The word defect is actually a misnomer since these phenomena can actually strengthen the properties of a material

Grain boundaries

Grain boundaries

02/17/17

“What happens when multiple grains in a crystal collide?”
Polycrystalline materials have grains that flow in numerous different directions. However, to make a continuous object, these grains must coalesce with one another. So what exactly happens at this grain boundary? Well, believe it or not, these grain boundaries actually cause the strength of the material to increase! The reasoning for this is that fragmentation along a material occurs across a row in a crystalline grain, so anything that limits this row will act as a dampener to the system.

Crystal grain

Crystal grain

02/16/17

“How do we describe when crystals have arrangements in different directions?”
Crystals are fantastic structures, with millions of different molecules being chained together in a uniform pattern. However, sometimes these chains will be in different directions from one another. Because these patterns are so prevalent, Materials scientists and engineers have decided to term this feature in crystals a grain. Grains are a very important property in materials and can have a large influence on the macroscopic behavior of a material

Body centered cubic structure

Body centered cubic structure

02/15/17

“How are materials such as Tungsten arranged on the molecular level?”
There are countless forms of materials that can be found in the universe. And the reason why these materials are different rests on the geometry of their subatomic arrangement. So let’s take a look at an arrangement called the body centered cubic structure. The atomic arrangement of the body centered cubic structure (commonly referred to as the BCC structure) can be discretized into a chain of cubic divisions. Each cube will contain two atoms, one in the center and ⅛ of another at each corner, giving this a packaging factor of 0.68. Because of this arrangement, materials that use a BCC structure such as tungsten and chromium are typically harder and less malleable than the average atomic arrangement.

Atomic packing factor

Atomic packing factor

02/14/17

“How can we quantify how much of a crystal structure is occupied by its particles?”
When working with crystals, it can be easy to forget that the entire volume of the structure is not occupied by its constituent particle. Because of this, it can be useful to quantify how much space is actually filled with material. After years and years of hard work and careful research, Materials Scientists have come up with a conceptual tool called an atomic packing factor. The atomic packing factor is calculated by taking the total number of particles in a crystal volume, multiplying it by their volumes and then dividing it by the total volume. This relationship can be quantitatively organized using the equation APF = (Number of atoms *Volume of atoms )/Volume of crystal. This procedure is useful for research in sustainable energy, as one would be able to analyze the properties of different types of photovoltaic crystals for solar panels.

Radius of gyration

Radius of gyration

02/13/17

“What would happen if we were to take the entirety of the object’s mass and concentrate it at a point?”
During one’s study of statics, one will have to work with the mass and moment of inertia for objects. However, could there be any ways in which we could simplify our calculations just a tad bit? Well, let’s think about it. Everything could be much simpler if we were to take the mass of the object and concentrate it at a single point away from the axis so that the resultant moment of inertia would be equivalent to original moment of inertia? This is the fundamental idea behind a concept known as the radius of gyration, and can be found with the equation k=Im, with k being the radius, I being the moment of inertia, and m being the mass.

Nuclear power generation

Nuclear power generation

02/12/17

“How exactly is Nuclear power generated?”
We hear about nuclear power very frequently in our lives. However, how exactly does it work? Well, to start let’s look at the process. The fundamentals of nuclear power start with two elements, uranium-238 and uranium 235. U238 composes the majority of uranium in a nuclear power plant, but perhaps the most important of the two is u235. Uranium 235 is very unstable and will decompose rapidly through nuclear fission. When U235 decomposes, it’s neutrons will be thrust throughout space. When these neutrons collide with U238, the element will be shattered into a stream of different particles, which will hit other elements. This quickly sets up a chain reaction which produces a large amount of heat. This heat is then used to boil water to generate steam to move a turbine which generates electricity.

How the poor will be disproportionately affected by climate change

How the poor will be disproportionately affected by climate change

02/11/17

“Is it true that fighting climate change will also fight poverty?”
In the current political discourse over climate change, there seems to be people camped on to two sides, those who value action to increase the impact of sustainable systems and those who value fighting poverty. However, if one were to analyze this issue scientifically, then one would realize that this is a false dichotomy. An increase in global temperatures would cause a corresponding devastation in agriculture. Not only would this inhibit the daily productivity of impoverished farmers worldwide, but it would also cause a rise in food prices. Since the global poor spend the majority of their income on food, this would cripple their livelihoods. On top of this, since much of the developing world lives near the equator, increased global temperatures will make this already balmy region even hotter, throwing the entire system out of equilibrium and devastating people of lesser economic means. Therefore, if you see a politician talk about how investing in sustainability is a “waste of money” please tell them to analyze the facts and then make an informed decision.