April 2021 M T W T F S S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Subscribe to Blog via Email
© Mark Biegert and Math Encounters, 2021. Publication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mark Biegert and Math Encounters with appropriate and specific direction to the original content.
DisclaimerAll content provided on the mathscinotes.com blog is for informational purposes only. The owner of this blog makes no representations as to the accuracy or completeness of any information on this site or found by following any link on this site. The owner of mathscinotes.com will not be liable for any errors or omissions in this information nor for the availability of this information. The owner will not be liable for any losses, injuries, or damages from the display or use of this information.
Author Archives: 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
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
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
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
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
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
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
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
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
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