How to prevent smartphone battery fires

The battery overheating problems of the Samsung Galaxy Note 7 have led to various efforts to mitigate the risk:

• The company recalled the smartphone, so consumers should return or exchange it.
• Airlines have banned the use of the smartphone or placing it in checked luggage on their flights.
• A software update from Samsung will limit battery charging to 60% of capacity.
• Some tech advice websites suggest disabling applications and background processes, limiting the use of games and web browsing, not using the device while recharging the battery, and avoiding third-party replacement batteries.

These suggestions range from risk avoidance to reducing the risk of overheating to reducing the consequences of overheating.  Many uses may simply accept the risk.

Links:
CPSC recall announcement: http://www.cpsc.gov/en/Recalls/2016/Samsung-Recalls-Galaxy-Note7-Smartphones/
Bloomberg article about software update: http://www.bloomberg.com/news/articles/2016-09-14/samsung-limits-note-7-battery-charging-to-prevent-overheating
Tips: http://gadgetstouse.com/gadget-tech/avoid-overheating-problems-smartphone/18946
Photo: A Samsung Galaxy S3 that exploded in 2013, from Le Matin.

Origami design process

In their article in the Journal of Mechanical Design, Jessica Morgan, Spencer P. Magleby and Larry L. Howell presented a design process for mechanisms that use origami (folding).

Their design process can be viewed as a separation in which there is a set of logically related decisions that must be made (subproblems that must be solved):

1. Decide to use origami solution.
2. Select the general material behavior options (hybrid, rigid, multiple, flexible).
3. Select a seed origami (fold pattern).
4. Choose modifications to the fold pattern, including the actuation method, the thickness, the hinge, and the manufacturing method.
5. Select the precise material.

Their paper lists some aerospace applications, including bellows to protect drill shafts on interplanetary rovers, an expandable habitat for the International Space Station, and
a parabolic antenna.

Reference:
Morgan J, Magleby SP, Howell LL. An Approach to Designing Origami-Adapted Aerospace Mechanisms. ASME. J. Mech. Des. 2016;138(5):052301-052301-10. doi:10.1115/1.4032973. 
http://mechanicaldesign.asmedigitalcollection.asme.org/article.aspx?articleid=2513965&resultClick=1
 

Estimating Cost and Time at NASA

The U.S. Government Accountability Office investigated NASA's program to build the Space Launch System and the Orion spacecraft and released a report that recommends changes to how NASA assesses the cost and schedule risk of these programs.

According the GAO, there are both technical challenges (such as the heat shield for the Orion spacecraft) and management challenges.  The two are related, of course, because "technical challenges could result in cost overruns and schedule delays."

For assessing the cost and schedule risk, NASA used a joint cost and schedule confidence level (JCL) analysis but followed few best practices for estimating cost and schedule.  In particular, "the Orion cost estimate met or substantially met 7 of 20 best practices and its schedule estimate met or substantially met 1 of 8 best practices."  The GAO concluded that "Without sound cost and schedule estimates, decision makers do not have a clear understanding of the cost and schedule risk" and recommended that NASA managers "perform an updated JCL analysis with cost and schedule estimates in line with best practices."

Links:
GAO report: http://www.gao.gov/products/GAO-16-620
Paper on JCL methodology: http://arc.aiaa.org/doi/abs/10.2514/6.2013-5524

Search Strategy for Pokemon Go

How do you find the Pokemon in Pokemon Go?  Just for fun, I developed a search strategy that has three phases: Explore, Calculate, Search.  You can find a description in my report.  Please let me know if you have suggestions or know of related work.

Book Award

At the IIE Annual Conference in Anaheim last month, Engineering Decision Making and Risk Management received the 2016 IIE/Joint Publishers Book of the Year Award.  I'd like to thank Gino Lim, who nominated the book, and those who supported this nomination.

The Wright Brothers

I just finished reading The Wright Brothers, by David McCullough.  It is a great story about two determined Americans who, like many engineers before and after, did their research and then designed, built, tested, improved, demonstrated, and marketed a remarkable invention.
The book describes not only their development process but also their personalities and family and friends, and I highly recommend it, but this is not a book review.

Flying is a risky endeavor, and Orville and Wilbur Wright made some key decisions to reduce personal and financial risk.  They decided to conduct their early glider and airplane tests at Kitty Hawk, North Carolina, which had not only good wind conditions for flying but also soft sand for landing.  They also decided to never fly together to avoid the risk that a crash would kill them both (only once, after many successful flights, did they fly together near their home in Dayton, Ohio).  They decided to keep their bicycle shop open to generate the profits needed to pay for the cost of their machines and the travel to North Carolina (they did not gamble their life savings on a speculative venture). 

On the other hand, they did accept some risk: they were not sure that their experiments would succeed, and every flight brought the potential for a crash.  Still, they learned from their failures, and managed the associated risks successfully.  Their story has important lessons about effectively managing risks.

UAV Operations and Failures

Earlier this month, the FAA's Micro Unmanned Aircraft Systems Aviation Rulemaking Committee (ARC) issued its recommendations in a final report: http://www.faa.gov/uas/publications/media/Micro-UAS-ARC-FINAL-Report.pdf

The recommendations include classifying UAVs (drones) into four categories, based on the risk that they pose to people underneath them.  If the UAV fails, it will crash and could cause a serious injury. 

If the mass of the UAV is less than or equal to 250 grams, then it would be in Category 1, which would have no additional restrictions (beyond those already in place).

UAVs more likely to cause a serious injury would face more restrictions.  For instance, Category 2 UAVs "must maintain minimum set-off distances of 20 feet above people’s heads, or 10 feet laterally away from people, and may not operate so close to people as to create an undue hazard to those people."  Category 3 UAVs would not be allowed to fly over crowds or dense concentrations of people.  A Category 4 UAV, on the other hand, could do that if it complied with a documented, risk mitigation plan.

There are many interesting details about the ARC, its risk attitude, how the ARC developed its recommendations, and other factors.  In particular, the ARC did not consider the likelihood of a UAV failure or the likelihood that it would hit someone if it failed; it considered only the distribution of the consequence (the chance of a serious injury) if it hit someone:  "Specifically, the ARC recommends that a small UAS be permitted to conduct limited operations over people ... if that UAS presents a 30% or lower chance of causing [a serious] injury upon impact with a person."