Monthly Archives: April 2013

Calculator to Select Connector for Joining Wires

Posted on 26-April-2013 by mathscinotes

I have written dozens (hundreds?) of small Mathcad function to help me in my daily work. Since I plan to teach another Mathcad class soon, I am gathering examples that might be good to use as application examples. Yesterday, I was working with a customer on selecting wires for supplying power to our products. I used an old calculator that I have decided to show my students in the class. I will discuss how I used this calculator here. Continue reading →

Posted in Electronics | 1 Comment

Photo Showing Ship On the Horizon

Posted on 22-April-2013 by mathscinotes

Quote of the Day Men are born ignorant, not stupid. They are made stupid by education. — Bertrand Russell (1872-1970). I see lots of problems with this quote, but there is an element of truth in it. I do think … Continue reading →

Posted in General Science, Naval History, Navigation | 2 Comments

Timing Differences Between Battleship Guns During a Salvo

Posted on 20-April-2013 by mathscinotes

Quote of the Day The better person you become, the better person you attract. — Pinterest. This is also true for management. I was looking at this picture (Figure 1) of the USS Missouri firing a six-gun salvo and I … Continue reading →

Posted in Naval History | Comments Off on Timing Differences Between Battleship Guns During a Salvo

Battleship Guns and Danger Space

Posted on 19-April-2013 by mathscinotes

I have been reading a couple of excellent books about battleships ("Naval Firepower" and "Guns at Sea"). During my reading, I have encountered the term "Danger Space" that appears with nearly every table describing the large naval guns. Of course, I had no idea what danger space was when I began investigating it. It turns out that danger space describes an important metric for battleship guns and it is worthwhile documenting what I have learned about it here. Continue reading →

Posted in History of Science and Technology, Military History, Naval History | 7 Comments

Questions That Don't Need to Be Asked

Posted on 17-April-2013 by mathscinotes

Some "interesting" questions come my way -- one just rolled in about my plans for dealing with an electromagnetic pulse attack (I don't have any plans for that situation). When I say interesting, I mean that this question really did not need to be asked. The best example of this type of question is one I heard when I was on a cruise ship. When I am on a cruise ship, I always ask if I can get a tour of the bridge -- they often do host a tour. During this tour, the ship’s navigator will sometimes offer to host a seminar on how the ship navigates. This actually happened and a number of passengers attended. During this seminar, the navigator mentioned that the ship normally navigated using GPS, but was equipped for celestial navigation if it was needed. The navigator then sheepishly added that his celestial navigation was very rusty because it had been so long since he had used it. A passenger than very seriously asked, “What if global thermonuclear war broke out and all the GPS satellites were destroyed – how would we find our way home?” The audience sat in stunned silence. I don't think that question needed to be asked. Continue reading →

Posted in Military History, Navigation | Comments Off on Questions That Don't Need to Be Asked

TSA Has No Sense of Humor

Posted on 13-April-2013 by mathscinotes

I was having a discussion with some other engineering managers when I heard the following travel horror story. Engineering managers are always talking about Bills of Materials (BOMs), which we pronounce as "bombs". An engineer was on his phone at an airport and was discussing part problems with a contract manufacturer. He used the term "bomb" many times during that conversation. Another passenger heard his use of the term "bomb" and turned him in to TSA, who promptly apprehended him. He then spent the next several hours explaining to the nice TSA people what a bill of materials is. While the TSA folks were very nice, he did miss his plane and got to spend an enjoyable evening in Little Rock, Arkansas. Did you know many things there are named after Bill and Hillary Clinton? This engineer got to visit a number of these places. Continue reading →

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Conversion Cost Mathematics in Mathcad

Posted on 13-April-2013 by mathscinotes

Introduction Normally, I use Excel for analyzing financial data. Today, I encountered a financial problem for which Mathcad seemed appropriate-- there was a bit of algebra involved. Let's see what you think ... Background Before I can state my problem, … Continue reading →

Posted in Financial | Comments Off on Conversion Cost Mathematics in Mathcad

A Couple of Examples of Characteristic Impedance Calculations in Mathcad

Posted on 12-April-2013 by mathscinotes

Introduction I have been doing some work that involves computing the characteristic impedances of cables. The work has involved creating some tables in Mathcad for comparison with tables from a government specification. Since I am always looking for real-life computations … Continue reading →

Posted in Electronics | Comments Off on A Couple of Examples of Characteristic Impedance Calculations in Mathcad

Epidemiology and Cell Towers

Posted on 10-April-2013 by mathscinotes

Introduction I received a phone call from a cancer epidemiologist last Friday. He had received my name from a co-worker in his department who knows me. This researcher is in the process of researching a cancer cluster near a cell … Continue reading →

Posted in Electronics, Osseo | 2 Comments

Neat photos from the International Space Station

Posted on 5-April-2013 by mathscinotes

Neat photos from the International Space Station Some co-workers and I are practicing speaking German while at work. One of these co-workers found some great photos on the Der Spiegel web site, which is a site we use for practice. … Continue reading →

Posted in Astronomy | Tagged | Comments Off on Neat photos from the International Space Station