Author Archives: mathscinotes

US Daylight Saving Time Date Calculation in Excel

Posted on 14-March-2021 by mathscinotes

I recently had a situation where I needed to correct a number of date/time values because they did not take into account Daylight Saving Time (DST). To be specific, some transactions from China were recorded assuming a fixed time offset with respect to US Central Standard Time. Because of DST, this is not always the case. My customer only works in Excel, so the work was done in Excel. Continue reading →

 
Posted in Excel | 3 Comments

Taffy 3 Total Displacement vs Yamato Using R

Posted on 10-March-2021 by mathscinotes

I was watching a documentary on the Battle Off Samar on my favorite Youtube naval channel called Drachinifel. During this show, Drachinifel stated that the battleship Yamato displaced more tonnage than the entire Task Group 77.4.3 (call sign Taffy 3) defense force. I found this a remarkable statement and one that I could verify using a little bit of web scraping. Because one of the students I tutor use R, I thought this would be a good exercise to implement using R and Rmarkdown (a great report generation tool). Continue reading →

 
Posted in History Through Spreadsheets, Naval History | Leave a comment

US Battleship Fuel Usage

Posted on 16-January-2021 by mathscinotes

In this post, I will examine the fuel consumption of the three most modern battleship classes that the US deployed during WW2: South Dakota, North Carolina, and Iowa classes. The data is scraped from the Hyperwar website, which is one of my favorite targets for data extraction. In this case, the Hyperwar page contains a set of tables from the US Navy document FTP 218: War Service Fuel Consumption of US Navy Surface Vessels. Continue reading →

 
Posted in History Through Spreadsheets, Military History, Naval History | 3 Comments

50 Destroyer Pre-War Base Deal

Posted on 7-January-2021 by mathscinotes

This post is going to look at the Destroyers for Bases deal between the US and UK. The bargain was an executive agreement announced on 2-Sep-1940 to trade 50 WW1-era US destroyers to the UK for US basing rights in the Caribbean, Bermuda, and Newfoundland. I have seen the destroyers described as obsolete, which seemed odd for ~20-year-old destroyers that nominally have 30 year lifetime (typical for most US Navy ships). Continue reading →

 
Posted in Excel, History Through Spreadsheets, Military History, Naval History | 1 Comment

BB Ballistic Coefficients

Posted on 29-December-2020 by mathscinotes

A number of years ago, I was asked by a father to assist him and his son with a science project that involved calculating the ballistic coefficient of a BB gun projectile. I provide dthis father-son duo with the required calculations (documented here) and the answer I obtained seemed reasonable. Continue reading →

 
Posted in Ballistics, Excel | Leave a comment

Optimized Piecewise Linear Model Using Excel

Posted on 23-December-2020 by mathscinotes

I was recently asked to create a piecewise linear model for a rather complex battery discharge curve, which is a type of task that I have performed dozens of times. I was told to perform this task in Excel because that is the only computation tool that this customer uses. I normally do this task in R because I like the segmented package, however, Excel does a very good job with the task, especially if you use the Solver add-in to "tune" the model. Continue reading →

 
Posted in Batteries, Excel | Leave a comment

US WW2 Torpedo Production Chart Using Power Query

Posted on 12-December-2020 by mathscinotes

During my readings on the Pacific War, I often see the chart shown in Figure 1. I decided to do a bit of digging and find the source data for this chart in the hope of making a version of this chart that is a bit clearer and easier to use. Continue reading →

 
Posted in Excel, History Through Spreadsheets, Military History, Naval History | Leave a comment

18% of American's Can Determine 52 Senators?

Posted on 6-December-2020 by mathscinotes

I was listening to a podcast this week where I heard James Carville state that "18% of American's can determine 52 senators." I thought this was an interesting quote that I could have the students I tutor verify using Excel and Power Query. All of the data is available online and the problem has a relatively short solution. Continue reading →

 
Posted in Civics Through Spreadsheets, Excel | 1 Comment

Willie Mosconi and How Pool is Like Life

Posted on 7-November-2020 by mathscinotes

I was talking with my neighbors yesterday about motivating students. They are both teachers at a local college and are finding it difficult to excite their students over Zoom.  While I am not in education, many of the companies I have worked for have struggled to motivate staff (local and remote). My employers would occasionally have occasionally brought in motivational speakers to try to fire up the workers, most of which were good but not great (Lou Holz was great). Continue reading →

 
Posted in Management, Personal | 4 Comments

Relative Cost of WW2 US Fighters

Posted on 19-October-2020 by mathscinotes

A reader of this blog mentioned in a comment that cost might be a big reason for the US Army Air Corps (USAAC) switchover to the P-51 from P-38s and P-47s. I thought I would put together a quick report on the relative cost of the three main USAAC fighters. The cost of these fighters by year was available in the Army Air Forces Statistical Digest (Hyperwar Site). The approach to Extracting, Transforming, and Loading (ETL) the data are the same as I used to determine the on-hand numbers of aircraft (link). For those who are interested in the details, my workbook is available here. Continue reading →

 
Posted in Excel, History Through Spreadsheets | 2 Comments