Clippings

New Helmet Design Uses Biomimicry to Reduce Rotational Injuries : TreeHugger

New Helmet Design Uses Biomimicry to Reduce Rotational Injuries : TreeHugger.

"Considering with good reason that the best helmet had already been invented by nature, he postulated that the skin on the skull, our scalp, played an all-important role in the event of an impact and was able to demonstrate that the same effect was achieved by putting a lubricated membrane on a helmet." (Dr. Ken Philips)

Lazer Helmets developed the SuperSkin Helmet that incorporates Dr. Philips' Head Protection System that reduces the impact of "rotational acceleration" that can occur when a hard helmet hits the ground.  The brain is not fixed within the head - the lag in transferring the rotational motion to the brain can result in tears in blood vessels and nerve fibers. 

Emulating the way the scalp protects the head and brain, the SuperSkin Helmet has an outer membrance separated from the helmet by a lubricant.  This system absorbs some of the rotational forces before they affect the helmet itself.

The website includes some of the biomechanical research that went into development of the helmet.

Technology Review: Why Fish Hold the Key to Increasing Wind Farm Power

Technology Review: Blogs: arXiv blog: Why Fish Hold the Key to Increasing Wind Farm Power.

The way schooling fish swim reveals how to squeeze more power from the wind over a given area of land.

A Caltech (Pasadena) team lead by Bob Whittlesey believe principles learned from the dynamics of schooling fish can significantly increase the packing density of wind farms using vertical axis turbines. Whereas the more common (and individually more efficient) horizontal wind turbines need to be widely spaced because the turbines impede the airflow around them, vertical wind turbines can increase airspeed around them by forming a 'Karman vortex street'. In nature, these vortices help synchronize schools of fish and reduce the power each fish needs to expend. 

Karman vortex streets often cause engineering challenges such as vibration.  In this case, the Caltech model suggests the dynamic nature of the vortices can increase the power density of a vertical wind turbine array by more than 10-fold.

Animations of Karman vortex streets can be viewed at http://www2.icfd.co.jp/menu1/karmanvortex/karman.html.  The Caltech paper can be downloaded at Fish schooling as a basis for vertical axis wind turbine farm design.