Dont forget to eat some fruits or vegetables in these days!

In these days of Christmas vacations, we were intensively submitted to a deep gastronomic show due to the rich meals with family, relatives and friends. All of us know how important is to have a right diet expecially to prevent different types of diseases like as coronary heart or neurodegenerative diseases. For these reasons but not only for these ones, of course, we need to program a correct diet that doesnt forget about fruits or vegetables, that are really rich in substances, known as antioxidants. What are antioxidants? Antioxidants are molecules capable of slowing or preventing the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent. Antioxidants are often reducing agents such as thiols, ascorbic acid or polyphenols. Measurements of the antioxidant activity or the oxigen radical absorbance capacity (ORAC) are not easy to process. There are different tests like as for example the DPPH test. The DPPH test, which utilises a redox reaction with the 2,2-Diphenyl-1-picrylhydrazyl radical, can be used to determine the antioxidant activity of plant or fruits extracts. The radical has a violet colour due to the unpaired nitrogen electron and after reaction with a radical scavenger the reduced DPPH-H (2,2-Diphenyl-1-picrylhydrazin) is formed which is yellow. The colour change can be followed spectrophotometrically at 515 nm and in this way the antioxidant activity of a substance or a plant extract can be determined. Anyway, despite the amount of antioxidants levels in fruits or vegetables, their consumption have to be done in a proper way for a good and healthy life.

New materials for green buildings

The role of chemistry in projecting new buildings is imporatant, because new materials with better thermal properties for example have to be used. One of the problems of an efficient house is its capacity to be insulated to avoid dispersion of energy in the external environment and to minimize the use of energy. We need to use less energy and to use it in a more efficient way. New materials that are able to do a thermal insulation and that are made by recycled materials are a good options to build up green houses. In the last years, in the market there are materials made with around 85% of cellulose fibers from recycled newspapers, around 15% of boric acid, used as flame retardant. These materials are used for insulations of walls. There is a big work to do in finding new materials, may be with better thermal properties. You can find several informations about this concept by visiting this website on cellulose materials for building or this italian website about ecomaterials.

Building green: a sustainable way to the future!

Houses and buildings are responsible of a big consumption of electricity and emission of carbon dioxide all over the world. In the USA buildings and houses use around 70% of the electricity produced. Buildings require 40% of resources of our planet and they are planned to be not really efficient. In the last years a new idea of projecting houses, industries and commercial buildings grew up, based on sustainable priciples. Green buildings are constructed by using recycled materials, by avoiding dissipation of energy and with the possibility to become center of renewable energy production (through solar cells or photovoltaic plants). Reuse of water and ecological water treatment aid to preserve water resources and to plan a better future. In this scenario, the role of the materials scientist is really important, expecially in the study and choice of the materials to be used in the green buildings. There are all over the world agencies that work to give energetic certificates for green building like Casa Clima in Italy and USGBC in USA. The request of energetic certificates grew up in the last years all over the world and this helps us in reducing the emission of carbon dioxide and in managing in a better way our planet resources.

Another funny experiment about supersaturated solutions

I attach here a new video about supersaturated solutions to enhance the fact on how powerful is to show this funny aspect of chemistry as a great educational tool. Supersaturated solutions are in a metastable state so that any "disturbator" (crystal seeds or impurities for example) can easily makes the system fall down into a lower energy state as it happens in these experiments.

Supersaturation and the Diet Coke and Mentos eruption!

Since I love to discover funny experiments, I have been searching for something interesting and found the famous Diet Coke and Mentos eruption experiment. This experiment became really famous all over the world cause of you tube videos diffusion. Recently there was a study made by Tonya Coffey, a physicist at Appalachian State University in Boone, North Carolina, that explained the chemistry and physics behind this experiment. The group of Tonya Coffey summerized the results, concluding that the vigour of the jets depends on various factors that affect the growth rate of carbon dioxide bubbles and particularly the rough, dimply surfaces of Mentos that encourage bubble growth, efficiently disrupt the polar attractions between water molecules, creating bubble growth sites. Diet Coke, like also other carbonated beverages, is a supersaturated solution of carbon dioxide in water. At atmospheric pressure, the carbon dioxide gas escapes very slowly from the supersaturated liquid. This process may be accelerated by the presence of nucleation sites within the solution, such as small bubbles, caused by shaking the bottle, or another solute, such as sugar powder. If you are interested you can find more informations at the American Journal of Physics. Supersaturation happens when the solution contains more of the dissolved material than could be dissolved by the solvent under normal circumstances. For example, we can obtain supersaturated solutions by melting some salts like sodium thiosulfate pentahydrate and cooling slowly the solution obtained. By adding some crystals of the salt, that act as seeds, we provide a rapid crystallization of the system. Supersaturation experiments are really funny and could be an easy tool to attract young students to chemistry!

Algae biomass: a source for energy

In last years, there was a big interest in developing new technologies to produce energy in a more efficient way and furthermore from renewable sources. The growth of population and the the consequent growth of energy request as well as the use and consumption of oils and C-based fuels and the produce of carbon dioxide raised up the research for new sources of energy based on renewables. One of the most interesting renewable source is the algae biomass. Actually there are some experimental plants that use microalgae to convert carbon dioxide or other types of feeding substances like waste water and sun light to biodiesel. These plants are called photobioreactors. The lipid content depends on the type of microalgae and could be really high up to 70 % in dry weight. This is a promising renewable sources since some types of algae can grow also in saline system and there will be the possibility to couple water remediation with the production of biodiesel and energy.

Nuclear energy: some facts!

In the last years, the problem of energy policies was one of the most discussed in the majority of western countries. We need energy and need to plan the supply of energy for the future generation in a sustainable way. In Italy the government wants to consider again the nuclear energy as an alternative way to produce energy for the country. But there are always problems that we have to take into considerations like:
High costs
Uranium supplies limited
Production of nuclear wastes
Security problems
Accidents problems of the plants
There are several facts about these problems that everybody can analyze in a better way, but the conclusion is that we need to reduce our needs of energy by starting to live in a more sustainable way!