CAJ 11 - Overview

As the CAJ project comes to its end quite soon, I would like to summarize what I have learned so far and what I have written about. As environmental technology is a very wide field of study, I could not nearly include everything there is to say or to write about it. However, I have tried to write about the most promising new technologies and how they could help us. In the end, I focused especially on solar energy because there is so much going on in this field right now and because some of the most promising concepts were developed there.

Solar cells are not only great because they function with the free energy of the sun but also because there are so many potential applications. One of the best concepts is Solar Roadways, in which normal asphalt roads would be exchanged with solar panels. You could drive on them, recharge your electric car and write warnings on a road that is never wet. There also is a new material for solar cells, called Perovskite that can not only absorb light but also emit it. Furthermore, the third generation of solar cells, the organic solar cells combine almost every advantage of solar power without real disadvantages. They can be produced cheaply, without the use of rare materials and use little energy in their manufacture. Solar power can also be harnessed in Space, where there is enough space available and where the power of the sun is even stronger.

Another concept which can be combined with solar energy but can also stand by itself is infrared energy. Researchers have found out that it is also possible to generate energy through temperature differences. So, it would be possible to collect energy when heat leaves a surface. For example, solar cells could generate energy by collecting light during the day and leaving infrared light during night.

A more controversial topic is nuclear energy. Everybody knows that this energy can be dangerous but there are ways to generate energy quite safely. The famous fusion reactor has never really worked and there still has to be more research done but the fusion-fission hybrid reactor could actually work pretty safely and without a lot of radioactive waste. Of course there are ethical questions to be raised but nuclear energy could be a technology of the future.

CAJ 10 - Three Generations of Solar Cells

In search of potential weaknesses or disadvantages of solar cells, I ended up at the website of the Technical University of Denmark. In their online course they defined three types of solar cells, from the first generation to the third. I will now explain the advantages and disadvantages of each of them:

First generation – Silicon Solar Cells:

The first solar cells were made of crystalline silicon and are what everybody has in mind when thinking of solar cells. They are thick, rigid, heavy and very inefficient. The materials they use are very expensive and their production consumes a lot of energy. That is why they were only used when really necessary, where the price of the energy was not important like in space, on satellites.

Second generation – Thin Film Solar Cells:

The next generation of solar cells was much lighter and easier to produce. Instead of building such big cells like the first generation, the solar cell was now a thin film on a carrier substrate. A popular example of second generation solar cells is the amorphous silicon solar cell. It solved most of the problems the first generation had. The manufacturing temperature was much lower, the energy consumption in general was low and the materials were not as expensive. However, with these advantages came some inherent problems. They were not as stable as the older ones, suffered from bad contacts, sensitivity to the atmosphere like water and oxygen and a decay in performance.

Third generation – Organic Solar Cells:

The new generation of solar cells are the organic ones. They can be produced at even lower cost and temperatures and use even thinner films. There is an indefinite number of materials and ways they can be built. Moreover, they operate at an average 10% or more efficiency rate, are extremely thin, use very little material and can be manufactured even faster than the second generation. The only potential problem with them is that they can also be unstable like the thin film solar cells. Other than that, there lies a huge potential in this third generation.

This already answered part of my question. I know now that there can be solar cells, which are not especially environmentally friendly because they use much energy and materials when being produced. However, with this third generation, this problem is solved and solar power really seems so be one of the very best renewable energy sources.

CAJ 9 - Solar Power Satellite

I have already written quite a lot about solar energy and the different new possibilities and materials. In May the Japan Aerospace Exploration Agency (JAXA) has announced that their goal was to build a solar power satellite that would generate as much energy as an ordinary nuclear power station does. This solar power station would then orbit the earth and would collect solar energy 24 hours a day because of two huge mirrors to get the sun at every angle. They say that this could be achieved within 25 years. While there are clearly some issues still to be addressed, they have managed to solve the main problems like wireless power transmission over such a long distance. The current solution to this specific issue are microwaves because they do not get blocked by the atmosphere and because the power conversion into electric energy from microwaves is already very efficient. For Japan this is a logical step because the country has no fossil fuels to exploit, space for renewable energy is scarce and because of the accident of Fukushima nuclear energy does not seem to be the right solution anymore. The plan is very ambitious and there still has to be more research done, for example in the field of possible materials, but if Japan succeeds in doing this, many science fiction movies would come to life.

http://spectrum.ieee.org/green-tech/solar/how-japan-plans-to-build-an-orbital-solar-farm

Photography Project - How Instant Photographs Work

How do normal cameras work?

To understand instant photography, one first has the know the basics of conventional photography. Normal cameras project the image onto the film, which then has to be developed externally. The film needed for normal pictures consists of a plastic base which is coated with three layers of light-sensitive silver compound. Each of the three layers reacts to a different light spectrum. The top layer is sensitive to blue light, the middle layer to green light while the bottom layer reacts to red light. When hit with light, each of the layers react to the light and form metallic silver in the according layer. This chemical record is then developed with the help of chemicals called developers.

What is the difference between this and instant photos?

Instant photographs develop the photograph inside the camera itself. To facilitate this, special instant film is required, which is loaded into the camera. Each of these films results in a print, just like paper that is loaded into a printer.

How does instant film work?

Instant film consists of the conventional three light-sensitive layers and special additional layers for instant photography. Under each of the three color layers, there lies one developer layer. On top of these layers, lie three more layers: the image layer, the timing layer and the acid layer. All these layers together sit on top of a black base layer. There is one more layer, which sits between the light-sensitive layer and the image layer. This layer contains the reagent, which together with the reagent material breaks loose the chain reaction that results in the developed photograph. At first the reagent material is collected at the border of the film, but when the picture is snapped, the film is passed through rollers, which spread the material out into the middle of the film. As a consequence the reagent reacts and the chain reaction starts. When the chemicals have taken full effect the picture will appear on the film.

[332 words]

CAJ 8 - Online Course!

There is something even more interesting. There is an online course about organic solar cells. I have never done such a course, but it is free and it starts on June 2^nd. I already signed up to take it, even though the CAJ will be near its end by then. I am thrilled to see what this course will look like and what I have to do in order to pass it. Here is the link to the online course, which is organised by the Technical University of Denmark:

https://www.coursera.org/course/opv

CAJ 7 - Organic Solar Cells

I just found out that there are even more advances in the field of solar energy. Everybody knows the typical silicon solar cells but there also are organic solar cells. They are called organic because they use carbon-based materials to convert light into electric energy. Right now there still are some challenges to be overcome, such as only 5% efficiency compared to 15% efficiency in silicon solar cells. Furthermore the efficiency is worsened by instabilities against oxidation and reduction and by temperature variations. However, they also have major advantages. To start with, these solar cells are cheap to produce and it is possible to use roll-to-roll processing, which makes the production even more cost-effective. The manufacturing also consumes less energy than usual silicon cells. Moreover, the material is light and flexible and is therefore easy to transport, store and install. Due to the flexibility of the material it is also less prone to damage and failure.  One possible application for the material is the use on laptops, phone and even clothes. Even the military uses it by putting it on its tents to generate energy. What is special about it is that the molecule properties can be tailored by molecular engineering to fit the intended application. These organic cells can also be combined with conventional solar cells to form a hybrid solar cell, which combines the advantages of both. Hybrid solar cells have higher efficiency and could be printed in any form or color.

Abstract of “When Zombies Attack!: Mathematical Modelling of an Outbreak of Zombie Infection”

The purpose of this paper is to mathematically calculate the possible outcomes of a theoretical outbreak of zombie infection. Due to the fact that the mythical concept of a zombie can differ considerably, one specific type of undead had to be chosen. Accordingly, the type of zombie calculated in this model is the slow moving, cannibalistic and undead kind of zombie that spreads the infection through saliva. To calculate the prospects of human civilization which is attacked by zombies, one basic model was developed and was calculated similarly to usual infectious diseases. This model assumes three classes: the Susceptible (S), the Zombie (Z) and the Removed (R).  It then continues to clarify how S, Z and R interact with each other and uses Euler’s method to solve the equation. On this basis, different scenarios for the human civilization were modeled, such as latent infection, quarantine of the infected, treatment for the disease and impulsive eradication of the zombies. The only two cases in which the outcome for human civilization was not complete extermination, were the model with treatment and the impulsive eradication. However, the impulsive eradication was the only one to actually defeat the zombies, as the treatment only accomplished that a small group of humans could survive. Thus, the recommendation derived from this purely theoretical mathematical model is that humans would have to deal with the new zombies as quickly as possible to avoid human extinction.