According to the product information, “independent lab tests prove that just one layer of Green Glue Noiseproofing Compound between two layers of drywall or other similar building material dissipates up to 90 percent of noise. Unlike competitive soundproofing products, Green Glue Noiseproofing Compound cuts out the low frequency noises commonly produced by home entertainment and theater systems” (Sweets Network).  The compound costs less than .50¢ per square foot and can be used in new and existing construction.

Image Courtesy Sweets Network

Green Glue Noiseproofing Compound can be used in any fire rated assembly according to the International Building Code. It does not contribute to mold growth, is low V.O.C., and has almost no odor. The compound can be easily cleaned up while still wet with soap and water.

Image Courtesy Sweets Network

If you’re inclined to try slathering it betwixt your sheets of drywall, you can purchase Green Glue Noiseproofing Compound by the case (each of which contains 12 tubes) or by the 5 gallon pail. You’ll go through 1 – 3 tubes per 4′ × 8′ sheet of drywall depending on desired performance. The coverage of a pail of Green Glue is around 365 sq. feet.

Check out their website: www.greengluecompany.com

Cited:

WU XING:

Shhhhhh… I’m filing this under water.

Sweets Network. “Green Glue Noiseproofing Compound.” Accessed 07/14/10.  URL.

Yesterday I learned that researchers at MIT have developed functional plastic fibers that can detect and produce sound.  As you can imagine, my coffee cup almost instantly hit the carpet.  After I wiped up the spill, I dug a little deeper to find out what this singing fiber business is all about. 

It seems that the new acoustic fibers are composed of a conducting plastic commonly used in microphones that contains graphite, the same material found in pencil lead and in my leg, from the time when I accidentally stabbed myself with a pencil in my sleep.  (Have I mentioned that I can be a little bit accident-prone?) To make fibers, long strands are drawn from a heated “preform,” (a large cylinder of a single material) and are then cooled. 

The fibers “derive their functionality from the elaborate geometrical arrangement of several different materials, which must survive the heating and drawing process intact.  By playing with the plastic’s fluorine content, the researchers were able to ensure that its molecules remain lopsided — with fluorine atoms lined up on one side and hydrogen atoms on the other — even during heating and drawing.  The asymmetry of the molecules is what makes the plastic “piezoelectric,” meaning that it changes shape when an electric field is applied to it” (Hardesty).  In other words, the composition of the plastic allows it to retain its useful properties throughout the process of forming it into thin strands.

Because the conducting plastic used by the researchers maintains a higher viscosity (stays thick) when heated, it allows the scientists to draw out fibers with uniform thickness.  They then apply an electrical field that is – get this – 20 times as powerful as the fields that cause lightning during storms – to the plastic in order to align all the piezoelectric molecules in the same direction.  If the fibers aren’t uniform, the electric field would generate a tiny lightning bolt!!

Photo: Research Laboratory of Electronics at MIT/Greg Hren Photograph

Despite the inherent challenges of the manufacturing process (incidental lightning and so on) the researchers built fibers that you can actually hear when you connect them to a power supply and cause them to vibrate.  As the frequency changes, the fibers emit different sounds (Hardesty).  The fibers are incredibly sensitive to vibration, which means they are capable of responding to changes in their surrounding environment.

The potential applications of these acoustic fibers include wearable microphones and biological sensors, loose nets that monitor the flow of water in the ocean and large-area sonar imaging systems with high resolutions.  Fabric woven from acoustic fibers would provide the equivalent of millions of tiny acoustic sensors, which could be used to create clothes that act as sensitive microphones for capturing speech or monitoring bodily functions.  Tiny fiber filaments could measure blood flow in capillaries or pressure in the brain (Hardesty).  These fibers are fantastic, and (AHEM) I’d love to get my hands on some!

More information:“Multimaterial piezoelectric fibres.” S. Egusa, Z. Wang, N. Chocat, Z. M. Ruff, A. M. Stolyarov, D. Shemuly, F. Sorin, P. T. Rakich, J. D. Joannopoulos, and Y. Fink. Nature Materials, 11 July 2010.

Provided by Massachusetts Institute of Technology (news : web).

WU XING:

I’m categorizing these fibers under WOOD because they’re plastic, and FIRE because of the heat and electric field required to make them.

Cited:

Hardesty, Larry. “Fibers that can hear and sing.” Physorg.com. 07/12/10.  Accessed 07/13/10.  URL.