Author Archives: mathscinotes

Computing Bacteria Reproduction Rate and Doubling Time

Posted on 22-July-2020 by mathscinotes

Until the arrival of the coronavirus, I looked forward every week to volunteering at a local library as a tutor for university students. Now that COVID is raging around me, I have moved the tutoring online. Most of the students are training for some form of a medical career. This week a student presented me with bacterial growth data and was wondering how to estimate the growth rate and doubling time for the bacteria using Excel. This exercise nicely illustrates the entire data analysis process (Figure 1) in a single example and I decided to post my solution here. Continue reading →

Posted in Excel, General Mathematics, Health, optics, Statistics | 2 Comments

Estimated Range Between Radios Based on RSSI

Posted on 18-July-2020 by mathscinotes

I recently have been working on Bluetooth Low Energy (BLE) systems and estimating the distance between two devices based on the Received Signal Strength Indicator (RSSI) value is one of my tasks. There are all sorts of uses for this distance information in wireless systems. Continue reading →

Posted in Electronics, Physics | 4 Comments

Gravity on Von Braun Station

Posted on 25-April-2020 by mathscinotes

I have been reading about Wernher von Braun's work with Disney on popularizing the idea of spaceflight with the public. He was a genius at marketing and a tireless champion for space flight. In addition to his television work, he also gave numerous speeches to any group that would listen. I smile as I think about my high‑school physics teacher beaming with pride when he spoke of von Braun arriving in a helicopter to speak to local physics teachers about space and flying to the moon. My physics teacher could not remember the details of what von Braun spoke about, but his entrance and exit in a helicopter made a huge impression on a town of 1800 people! Continue reading →

Posted in Space | 6 Comments

The Amazing de Havilland Mosquito

Posted on 18-April-2020 by mathscinotes

During the routine demolition of an old de Havilland Aircraft building in 2017, a treasure trove of 20K aperture cards (a microfilmed archive) was uncovered that contained plans for the Mosquito fighter-bomber (Figure 1). These plans have been lost since Mosquito production ended in  1950. Continue reading →

Posted in History Through Spreadsheets, Military History | 4 Comments

USNS Comfort Bed Count Relative To Other US Hospitals

Posted on 4-April-2020 by mathscinotes

Because of COVID-19, I am currently sheltering-in-place at my cabin in northern Minnesota. I was reading news reports of the USNS Comfort docking in New York City to provide the city with another 1000 bed hospital. I had no idea as to the average size of a hospital and decided to take a quick look at the number of beds in hospitals around the United States using a histogram. Continue reading →

Posted in Civics Through Spreadsheets, Excel | 3 Comments

Maple Sap is Sweet This Year

Posted on 26-March-2020 by mathscinotes

I am being a good citizen and am socially distancing at my cabin in northern Minnesota – avoiding people is easy in the dense forests that surround my residence. When I went out for my daily walk and I saw the maple sap bags that my neighbor put out (Figure 1). Most folks around here collect their sap in these blue bags. Continue reading →

Posted in Cabin, Personal | Comments Off on Maple Sap is Sweet This Year

WW2 Fighter Aircraft Fuel Fraction

Posted on 22-March-2020 by mathscinotes

I recently read a book called Boyd: The Fighter Pilot Who Changed the Art of War that documents the life of John Boyd, a fighter pilot who was critical to putting fighter aircraft design on a firm mathematical footing now called Energy-Maneuvering Theory. He was a key member of the Fighter Mafia, a group of military and industry experts in the 1970s that advocated for a lightweight fighter alternative to the large, heavy fighters like the F-111 and MiG-25. Their concepts played a significant role in the final designs of the F-16 and F-18. Continue reading →

Posted in Excel, History Through Spreadsheets, Military History | 2 Comments

Combined Excel Timeline/Column Chart using WW2 Naval Air Data

Posted on 10-March-2020 by mathscinotes

I recently needed to generate a graph in Excel that combined a column chart with a timeline. The graph turned out well and I decided to share my work here. As my original work is proprietary, I will share the technique here using some US Navy (USN) air operations data from WW2. Continue reading →

Posted in Excel, History Through Spreadsheets, Military History | Comments Off on Combined Excel Timeline/Column Chart using WW2 Naval Air Data

Web Scraping Sailboat Reviews Using Power Query

Posted on 25-February-2020 by mathscinotes

While it is true that I worked on US Navy contracts for twelve years and spent some time on ships testing new underwater vehicles, I know very little about recreational boating. However, I have always been fascinated by sailing, though this fascination has been limited to reading books about the Age of Sail. Continue reading →

Posted in Excel, Personal | Comments Off on Web Scraping Sailboat Reviews Using Power Query

Visualizing House of Representative Data Using Power Query

Posted on 18-February-2020 by mathscinotes

I have been following certain bills through the US House of Representatives and wanted to know how the voting varied by US regions and political parties. I also want to generate tables that show how my state's representatives vote (Figure 1). Fortunately, the votes are documented online and Power Query was able to easily grab and process the data. Continue reading →

Posted in Civics Through Spreadsheets, Excel | Comments Off on Visualizing House of Representative Data Using Power Query