Security Enhanced (SE) Android Released

In early January (January 6, 2012) the US National Security Agency (NSA) released the first public ​version of Security Enhanced (SE) Android.  This past week, more articles mentioning it were published such as "NSA Releases SE Android With Better Sandboxing, Access-Control Policies".

SE Android is based on SE Linux (originally released back in 2000) and implements stricter access-control policies and sandboxing.  Applications, processes, and applications are now isolated from each other.  File-level permissions and and individual locking/encryption has been enabled.

News has been circulating for months that the U.S. Army is planning on using Android devices and the first device using SE Android, Dell Streak 5, received accreditation and approval by DISA in October 2011,  "First Android device certified for Pentagon personnel".  The government-issue Streak 5 also includes DISA-approved security provided by Good Technology’s Mobility Suite.

Passive Solar (Photovoltaic) Tracking Systems

While doing more research on solar power systems recently, I discovered the ZomeWorks Track Rack system.  This is a passive PV tracking system that works based on solar heating of liquid inside the rack systems.  There are no complex electronics involved in this very simple design which is described at How ZomeWorks Trackers Work.  The ZomeWorks Track Rack system supports from two solar panels up to twelve and are priced accordingly.

ZomeWorks states that their passive PV tracking system can improve solar efficiency by 25%-40% over a static mounted PV system.  This is impressive.  They also have a few reference articles that have reviewed their designs in their Applications page.  The "To Track... Or Not To Track", HomePower Jun-Jul 2004 article contains an excellent review and overview PV tracking systems (passive, active) and explains how they work in more detail.  The article mentions doing a site survey using Solar Pathfinder device (available for $299) and available software (available for $189) which will evaluate specific locations for this solar potential.

Passive PV tracking systems are more reliable, have fewer components, require very litle maintenance, less accurate in cold/winter months, and are less expensive.  Active systems have electronic components and motors that increase their accuracy, maintenance, and cost.  So the trade-off in accuracy vs. costs and improvement in PV efficiency would require some type of decision analysis (break-even analysis) or other method to determine which one is better for your particular PV application.