Author Archives: mathscinotes

Why Use an Antilog Taper Pot?

Posted on 24-August-2015 by mathscinotes

I have received a number questions lately on the use of log and antilog taper potentiometers. Because of these questions, I thought it might be useful to review why these tapers are used. Continue reading →

Posted in Electronics, General Science | 1 Comment

Drying Up the Mediterranean

Posted on 22-August-2015 by mathscinotes

One of my favorite audio books is titled The Earth: A Very Short Introduction (link). This book provides an excellent overview of basic geophysics. It is not a book about rocks, but rather a book about the structure of the Earth. This book contains an excellent discussion of the Mediterranean's periodic drying episodes that are collectively known as the Messinian Event, which occurred five million years ago during the Miocene era. Continue reading →

Posted in General Science, Geology | 1 Comment

Sigmoid Potentiometer Taper

Posted on 21-August-2015 by mathscinotes

Yesterday, I had a question from a reader on how to develop mathematical formulas for different potentiometer tapers. Normally, I would simply answer the questioner without a separate post, but my solution for this particular question provided a nice illustration of basic coordinate transformations. Since I have not shown any coordinate transformation applications in this blog before, I thought it would be worthwhile to make a post of my response. Continue reading →

Posted in Electronics | 4 Comments

Electricity Generation Percentage from Coal By State

Posted on 20-August-2015 by mathscinotes

I drive a short distance (7 km) to work everyday. On my drive, I often have to wait at a railroad crossing for a coal-train train to pass (typical example in Figure 1). I have never thought much how much my state depends on coal until I saw an interview with a Missouri senator who was talking about her state's dependence on coal for electrical power generation. I am currently teaching myself how to use the Power Query add-in for Excel, and I thought that generating a graphic of coal dependence by state would be a good Power Query/Visio exercise. Continue reading →

Posted in General Science, software | Comments Off on Electricity Generation Percentage from Coal By State

How Many Red Blood Cells Do We Lose A Day?

Posted on 4-August-2015 by mathscinotes

I regularly visit the RefDesk website to pick up general information. Refdesk has a section that contains a Fact of the Day from the Random History website. Unfortunately, these "facts" are occasionally just plain wrong (example). Today, another one of these random facts did not seem correct and I thought I would perform a quick Fermi analysis here to show that it cannot be correct. I assume that they confused hours and minutes in their analysis. I will present my argument below. Continue reading →

Posted in General Science, Health | 5 Comments

Linking Data to a Visio Drawing

Posted on 3-August-2015 by mathscinotes

I enjoy collecting and occasionally creating pins for my Pinterest collection. There was one pin that I saw (Figure 1) that I thought would be a good exercise to use when I conduct training classes in Visio and Excel. This post will use a simple Excel table of planetary orbit data to drive the creation of similar graphic in Visio. I will make one change to the information contained in Figure 1 – I will add Pluto because I still like to think of it as a planet. I will also remove the black background because I find black a bit harsh for a background color. Continue reading →

Posted in Astronomy, software | Comments Off on Linking Data to a Visio Drawing

Stadiametric Rangefinding Approaches

Posted on 20-July-2015 by mathscinotes

Recently, I was reading about stadiametric range finding methods being used by hunters and their telescopic sights – I was surprised to find a lot of writing on the topic. As I researched the topic, I saw that there are three common approaches used in telescopic sights: milliradian (mil), Minute Of Angle (MOA), and Inch Of Angle (IOA). I will review these methods here. Continue reading →

Posted in Ballistics, General Mathematics | 2 Comments

Passive Optical Network Fiber Length

Posted on 17-July-2015 by mathscinotes

I recently was asked to explain how a Fiber-To-The-Premises (FTTP) system measures the length of fiber between the central office and each residence in the network (Figure 1). This is an interesting question and I thought it would be worthwhile to the describe the measurement process here. Continue reading →

Posted in Fiber Optics | Comments Off on Passive Optical Network Fiber Length

Sherman Tank Myths

Posted on 13-July-2015 by mathscinotes

When I was a boy, most of the fathers in my neighborhood had served in WW2. One of these neighbors, Alvin Weese, was an Army veteran who was very specific about his WW2 service by saying that he had "served under Patton" and you could clearly see his pride in having served in Patton's 3rd Army. Continue reading →

Posted in History of Science and Technology | 73 Comments

Greece GDP Versus State GDPs

Posted on 12-July-2015 by mathscinotes

I have been trying to understand the economic situation with Greece and its creditors, but it has been difficult because I do not have an intuitive feel for the size of the Greek economy. To understand a number, I need to relate it to something that I know. Continue reading →

Posted in Financial | 2 Comments