2010 NOBEL PRIZE FOR PHYSICS: THE MOST RESISTIBLE MATERIAL

The 2010 Nobel Prize for Physics went to the University of Manchester’s Andre Geim and Konstantin Novoselov for their experiments with graphene, the thinnest material in the world. But what exactly is it, and what could it be used for?

Carbon, but not as we know it!

Graphene is one of several forms of carbon known as its “allotropes”. Allotropes are structurally different forms of the same element, in which the same atoms bond together in different ways. For example, molecules of oxygen can bind together as two atoms – O₂, which makes up a fifth of Earth’s atmosphere – or as three atoms, ozone, which protects us from ultraviolet radiation.

In the case of carbon, aside from soot and charcoal, the most commonly known forms are diamond, graphite, and the fullerenes. In diamonds, the atoms are arranged in a pyramid shaped lattice. The atoms of graphite are sheets of hexagonal lattice, while fullerenes are similar lattices arranged into shapes such as balls (Buckminsterfullerine) or cylinders (carbon nanotubes). The different forms have different properties: diamond is electrically insulating and hard; graphite is an electrical conductor and is soft – hence its use as pencil “lead”.

One atom thick

Like graphite, graphene’s atoms are arranged in a hexagonal lattice. What distinguishes it is that rather than being made of stacked layers, graphene is one single layer just one atom thick.

There are several ways graphene can be produced. The method used by Andre Geim was to peel layers away from graphite using sticky tape until he had a single layer.

It’s also possible to “grow” graphene on other substances such as silicon carbide, or on metals. Some of the most important properties of the material have been found in graphene produced this way.

What could graphene be used for?

Graphene is one of the strongest materials known. It conducts heat better than diamond, and may conduct electricity better than silver. As it’s two-dimensional, it could be used to detect single molecules of a gas – if a gas molecule were to stick to a sheet of graphene there would be a local change in the electrical resistance. This could also be useful for detecting microbes.

Many of the proposed applications of graphene are in electronics and computing. Its electronic properties mean it could be used to make transistors for high-speed electrical circuits, and ultimately replace silicon in microchips.

At the same time, research in China discovered that graphene has some antibacterial properties and is effective at killing E Coli bacteria, leading to suggestions for its use in hygiene products.

All of this is remarkable for a material produced by, in the words of Geim’s fellow materials scientist and the Royal Institution’s 2010 Christmas lecturer, Mark Miodownik of King’s College London, “mucking about in a lab”, and is a testament to the value of blue-skies research.

WITH THIS DISCOVERY, ELECTRONIC AND CHEMICAL ENGINEERS WILL HAVE MORE WORK AND RESEARCHES TO DO!

Recent Article taken from: http://www.physics.org/article-questions.asp?id=67

"AUTO-REGENERABLE" PHOTO-CELLS

A new investigation based on the natural behavior of the plants, guide to a team of the MIT to imitate the capacity of repair itself applied to the photocells.

In the research of the MIT team working together with the Eni Solar center of MIT, on the study of the great capacity of destruction of the sunlight rays over the majority of elaborated systems in the photocells, put to Michael Strano, one of the researchers of the team to consider the innate capacity of the plants to make the capture of sunlight every moment, without any degradation and apply to the photocells. The natural form of the plants to catch the sunlight’s using the proteins in their chloroplast of their leafs to make the process of photosynthesis, and after a time, the proteins are broken using oxygen to decompose into a specific form of compound to reconstruct then again and continue the process of self-alimentation without any lose of efficiency in the new protein.

In the investigation of the photocell, they used seven different types of compounds, one of them are the phospholipids. The phospholipids form a support for the reactive molecules, and are organized in form of disk, they receive the released electrons of the other compounds when the light pass across then (the reactive proteins and phospholipids is a system called reactive centers) meanwhile the phospholipids form a link with carbon nanotubes to make a way for the electricity. The link between the disks and the nanotubes are made by a solution that join them in an automatic way and the strength and conductivity capability of this system is better compared with others natural elements in the nature (the strength of the steel and the conductivity of cooper).

The seven compounds (all are not mentioned) can be divided apart each one with the presence of a surfactant, making a soup solution, and after that, the surfactant can be removed if the soup pass across a membrane, and the solution form again the initial structure rejuvenated and without efficiency lose like the plant’s system, describing the result like the investigators, a copy of the process of the nature made million years ago. To support the capacity of the new cells, they made a test, making a great number of cycles in 14 hours without interruption, and observing that that didn’t have any lose in the generation of electricity.

A simple photocell.

The importance of the investigation is based on the comparison of the silicon-based photovoltaic cell, when the work on the time is studied; the efficiency of the system falls to 10 percent compared with the initial state, meanwhile the efficiency of the self-repair system don’t falls, represent economical and material saving to the producers. The problem is the low level of transformation of the photocells, they can transform 40 percent of sun light in electricity, because the new element have low concentration of the compounds in the soup, giving a new orientation to the new investigation: working in the improvement of the concentration of these materials in the dispositive to make it enough potential to change the old photocells.

THE IMPORTANCE OF LIQUID CRYSTAL IN ELEC-ENGINEERING

Schlieren texture on an LCD screen
of a PlayStation Portable viewed
through a circular polarizer

The properties of some compounds with the characteristics of the liquid and the solid have different applications in the electronic that improve some of elements in our daily living.

A liquid crystal, is a phase between the liquid and solid (called mesophase), in which the compound have the capacity of a free movement like liquid but have at the same time a orderly structure like the solid. The discovery was made by Reinitzer at the end of the nineteenth century. The general description gave by the structure of this state of matter is a group of molecules with a weak dipole-dipole interaction which have the enough energy to stay the orientation in the material (electron cloud makes a repulsion and attraction balance to give a common orientation between the molecules) but not enough to restrict the movement of the sample.

The most important characteristic in the different types of liquid crystal ( nematic, esmectic and colesteric) is the capacity of change the direction, the intensity or the color of a light ray, depending of the optic axis where is observed, like normal solid crystal that have applications in googles or polarized glass used to protect us from the sun; but the way of work of the liquid crystal is better, the optic axis can be changed of orientation because this have a weak interaction between the molecules and answer at the presence of magnetic field turning in a perpendicular or parallel way to the field.

The nematic crystal composition make it good for the pass of the light, one example is the electro-optical indicator, a nematic is ubicated in the middle of two glass linked to a polarizator to make the alineation searched in the object (a change of 90° in the direction of the molecules) after this, when the light pass, all the objects have the same direction to give pass to the light, the two polarizator and the glass can leave the light pass in both ways, in this case, the indicator have a mirror in the inferior part, to reflect the light back and an observator can see this very clear and transparent. After this if you make pass some electricity to certain areas with two electrodes to change the orientation of the nematic liquid crystal, and don’t let the light pass in both ways, only one and form a number or letter very obscure.

This work is used in digital calculators or clocks, to make glass like drape if the person decide it, the construction of very little thickness television, can give pass of different kind of light color depending of the application of electricity in the system and the possible next principal component of space ships panels, in the last case this offer high resistence to the heat, humidity and ambiental conditions, very fickle and cheaper than the ceramic work in the case, can give a good capcity of radiofrequency over the 110Ghz compared to the normal system with only 5Ghz that begin to work slow over this frequency; only needs to pass the low temperature and radiation test to be used in this new field.

ELECTRONIC AND CHEMICAL ENGINEERINGS ARE LINKED

“Both like only one”

Best of all this is that our university, one of Colombia (Seat Bogota) has the electronic and chemical engineering programs, which is the one with more years of experience in the country and according to the test ECAES is one of the best institutions in these interesting disciplines.

In synthesis, these engineering are aimed at helping to simplify everyday life situations, enhancing, facilitating or implementing a solution to any activity that affects the society where they are developing.

CHEMISTRY APPLIED TO "THE ENGINE DISCIPLINE"

Process engineers design, construct and operate plants

“The technology in chemistry towards the big industries”

Almost all the products we use every day are the result of the development of a very prominent discipline called Chemical Engineering. Professionals engaged in this career are known as chemical engineers.

The main reason for exists this discipline is because human beings need to get new materials and products that meet their needs. The current chemical industry moves quickly and progress is steady. However, none of this would be possible today without the great contribution made by Professor Davis of MIT (Massachusetts Institute of Technology). Davis was the first to introduce the concept of "chemical engineering" based on the role of an engineer, as the engine was operating an entire system.

In this case, the system would be an industrial plant, which will apply all the knowledge in chemistry, physics, mathematics, biology, environment and engineering, to generate innovative products from raw materials. This means that whenever we talk about chemical industry, we are talking about the most important workers are there: the chemical engineers. It is also important to note that a process executing a chemical engineer must contain certain stages called "Unit Operations".

On the other hand, this career is associated with other disciplines, mainly with other engineering and science. We can find a chemical engineer at a food factory, in a vehicle oil industry, a cleaning products company, in aircraft spare parts, at an university (like professor), research projects, and even CERN (European Organization for Nuclear Research), where experiments with antimatter and the LHC (Large Hadron Collider) to learn more about the origin of the universe.

All this indicates that this discipline is very complete and very important for the development of mankind in many ways. The modern world needs a lot of chemical engineers and fortunately, Colombia is growing as a country on the issue of products that reduce costs, high quality and do not affect the environment, such as biofuels.

References: http://en.wikipedia.org/wiki/Chemical_engineering