Author Archives: mathscinotes

Flattening the Golden Gate Bridge Deck

Posted on 13-April-2016 by mathscinotes

I recently read a post on Quora about the day that the arc of the Golden Gate Bridge was flattened by the load of a large number of people – some reports stated that as many as 300K people were present at the event. The bridge was opened opened to this huge throng of people as part of its golden anniversary. This was the first time I had heard of this event. Continue reading →

Posted in General Mathematics | Comments Off on Flattening the Golden Gate Bridge Deck

Naked and Afraid Statistics

Posted on 12-April-2016 by mathscinotes

I do not watch much reality television, but one show I do watch is Naked and Afraid (N&A). I have always been interested in primitive survival skills (e.g. I have blogged about knot tying and rigging), and this show really puts those skills to the test. I like the fact that the participants are presented with survival challenges from around the world (Figure 1). They have been on all the continents but Antarctica – I could not imagine someone surviving naked in Antarctica for any length of time. Continue reading →

Posted in Statistics | 71 Comments

Things Not to Do in an Interview

Posted on 9-April-2016 by mathscinotes

I have been in management since 1995, and I literally have hired many dozens of people and interviewed hundreds of people in the process. I have heard just about everything you can imagine in an interview. After a recent interview, I thought it might be useful to mention a few things not to do in an interview: Continue reading →

Posted in Management | 2 Comments

Product Design vs Research

Posted on 8-April-2016 by mathscinotes

I saw an interesting discussion on the Dynamic Ecology web site about publishing research papers. As I read the article, I saw that analogies could be drawn between doing research and developing new products. The Dynamic Ecology post was centered on observations made by William Shockley , 1956 Physics Nobel Prize winner, on what makes a successful researcher. Continue reading →

Posted in Management | 2 Comments

Temperature-Compensated SLA Battery Charging Voltage

Posted on 6-April-2016 by mathscinotes

Quote of the Day If the tiger ever stands still the elephant will crush him with his mighty tusks. But the tiger does not stand still. He lurks in the jungle by day and emerges by night. He will leap … Continue reading →

Posted in Batteries | 3 Comments

CO2 Tonnage Added To Atmosphere Per Year

Posted on 5-April-2016 by mathscinotes

My youngest son told me that I needed to watch the new Cosmos series with Neil deGrasse Tyson. I was immediately hooked – it is a masterpiece of scientific exposition for a general audience. I thought the original Cosmos with Carl Sagan was excellent, but the progress in computer graphics during the intervening decades makes the program visually stunning. Continue reading →

Posted in General Science | 6 Comments

Recent Asteroid Impacts on Mars and Jupiter

Posted on 4-April-2016 by mathscinotes

I liked this picture of the recent impact of a small asteroid on Mars. This impact crater is about 100 feet across and was not seen in NASA photographs prior to 2010 and was first seen in a photograph in 2012. The blue color is an artifact of the image enhancement process, which removed the red dust. Continue reading →

Posted in Astronomy | 5 Comments

A Little Heat Sink Math

Posted on 3-April-2016 by mathscinotes

I am conducting a seminar next week on cooling electronics. One of the topics I will cover involves basic heat sink usage. Most of the products that are designed by my team do not use heat sinks because we are not allowed to use fans in our designs – fan-based cooling systems generally have air filters that require regular maintenance that is unacceptable for optical hardware deep in the network (example deployment). Continue reading →

Posted in Electronics | 1 Comment

MTBF, Failure Rate, and Annualized Failure Rate Again

Posted on 2-April-2016 by mathscinotes

I just had another meeting where folks thought that specifications for Annualized Failure Rate (AFR), failure rate (λ), and Mean Time Between Failures (MTBF) were three different things – they are mathematically equivalent. I have given up writing the formulas down as a way to explain the concept. Maybe a graphic will illustrate the relationship better? I have tried this approach before – the most successful was about component temperatures. That graphic has saved me hours. Continue reading →

Posted in Electronics | 2 Comments

Unfortunate Satellite Launch Problem Allows Test of Relativistic Time Dilation

Posted on 1-April-2016 by mathscinotes

In November 2015, the European Space Agency (ESA) had a launch problem with two of its Galileo navigational satellites that resulted in both satellites being placed into highly elliptical orbits. ESA can burn some of the satellites' station-keeping fuel to bring these orbits back to standard, but this will take some time. While the orbit adjustments are occurring, ESA will use the satellites to provide another test of Einstein's general theory of relativity. Specifically, they will test the prediction that clocks will run slower the closer they approach a massive object. Continue reading →

Posted in Astronomy, Navigation | Comments Off on Unfortunate Satellite Launch Problem Allows Test of Relativistic Time Dilation