Monthly Archives: February 2015

Snowballs and Investing

Posted on 20-February-2015 by mathscinotes

Because I am an annoying father who wants to encourage his sons to invest, one of the things I like to collect on this blog are stories of successful, long-term, investors. I loved this story about a janitor, Ronald Read (Figure 1), who recently died at 92 and left an estate worth nearly $8 million dollars. Continue reading →

Posted in Financial | Comments Off on Snowballs and Investing

Fan Airflow Versus Static Pressure Diagram

Posted on 19-February-2015 by mathscinotes

I was so happy with my previous fan installation that I am considering replacing some old fans with new, higher throughput, and quieter fans. The installations will be similar to that shown in Figure 1.

I have been using a nomograph (Figure 2) for my home HVAC calculations (example). I have decided that I am now living in the 21st century and I should figure out the formula that this graph represents. In this post, I will generate part of this nomograph to verify that I have put together the correct formula. Continue reading →

Posted in Construction, General Science | 3 Comments

Cars With Zero Driver Deaths from 2009 to 2012

Posted on 18-February-2015 by mathscinotes

I saw an interesting article on Yahoo Autos about 9 cars in which zero drivers died during the time period from 2009 to 2012. I thought this was interesting information – it sure stimulated some discussion in my family. Continue reading →

Posted in Health | Comments Off on Cars With Zero Driver Deaths from 2009 to 2012

I Would Not Like to Have Worked For Frank Lloyd Wright

Posted on 17-February-2015 by mathscinotes

Because my wife and I are designing a cabin to replace our hunting shack in northern Minnesota, we have been looking at various house designs. Many of the designs we have looked at show the influence of Frank Lloyd Wright, who was the most famous member of the Prairie School of architecture. I know that Frank Lloyd Wright (Figure 1) is considered America's greatest architect (according to American Institute of Architects, 1991), but I do not think I would have wanted to work for him. Continue reading →

Posted in History of Science and Technology, Management | Comments Off on I Would Not Like to Have Worked For Frank Lloyd Wright

Designing an LED Backlight

Posted on 16-February-2015 by mathscinotes

I was reading an application note by Texas Instruments yesterday on how to design an LED backlight for an LCD display (Figure 1). The article was interesting, but it did bother me because it presented a rather involved formula and did not provided any motivation for the formula, a derivation, or even definitions of the parameters used in the formula. Continue reading →

Posted in Electronics, optics | 3 Comments

Bathroom Fan Selection

Posted on 1-February-2015 by mathscinotes

I recently began remodeling a small bathroom on the second floor of my home. I have never been happy with the ventilation in that bathroom, particularly during showers when it seems more like a steam room than a bathroom. I decided to upgrade the ventilation fan in this room and I have been very happy with the improved performance. Figure 1 shows how the fan looks on my ceiling − yes, I am experimenting with a wood ceiling . In this post, I will go through my fan selection process and my ultimate choice. Continue reading →

Posted in Construction | 4 Comments