Glass buildings can provide an appealing environment of light and openness, but too much sunlight will over heat the building, as well as creating glare. While conventional shades can be used to control light levels, a new option is to use a low power material attached to the glass that can quickly adjust to increase shading or let more light in as needed.

As shown by their presentation, the shading system developed by designers Decker Yeadon can be installed in an organic configuration to highlight the biomimetic nature of this material. These shades use a dielectric elastomer, which is stressed and changes configuration when a charge is applied. When actuated with a low-power electric charge, tension in the dielectric increases, which causes it to contract. As it does so, it pulls on the flexible polymer core inside it, causing the assembly to spread open and increase the shading.

The video clip demonstrates how it works with a sample section of the material that looks something like a butterfly opening and closing its wings. The dielectric surfaces of the material are coated with silver which acts as a conductor for the low power current needed to activate the material, as well as being an excellent reflector of sunlight to provide rejection of excessive daylight when acting as a shade.

The presentation implies that the actuation of the shading material is automatic, though it is unclear whether this is an inherent property of the material itself (which seems to be implied, but is not directly stated) or whether there is an external system controller that applies a charge when the system is to be activated. In either case, the fact that the system requires low power makes it an intriguing option. And since "the shade is the motor," very localized control is possible with the material.

This system is intended for use inside a double-wall glazing system, presumably because it is far too delicate to be exposed to weather if it was exposed on the outside of a building. Because of this, it is unlikely to be a widely adopted solution, but it does represent a first step with an intriguing material that has many potential uses beyond just green buildings.

via: Treehugger

Cement is one of the most significant single sources for carbon emissions, due to the intense energy required for its production and the volumes of it that are produced annually, as well as from material itself, but an alternative is now available. It doesn't just reduce the amount of carbon dioxide emitted, it actually binds more CO2 than is emitted from its production, which makes its production carbon negative.

Novacem has developed a new cement that uses magnesium silicate instead of calcium compounds. The new material is supposed to have performance and cost comparable to ordinary Portland cement. Furthermore, because the production of magnesium silicate is a lower energy process, it can be manufactured using biofuel, instead of requiring more intensive and polluting energy sources.

The company also notes that "production of our cement is carbon negative; more carbon dioxide (CO2) is absorbed during the process than is emitted." Manufacturing a tonne of this cement results in the absorbtion of up to 100 kg (220 lbs) of carbon dioxide more than is emitted in the process.

Magnesium oxide is widely available as well, so there should not be an issue of material scarcity with the use of this as a Portland cement replacement. The company is not producing the material itself, but is instead seeking to license its technology to producers.

via: Jetson Green