Author Archives: mathscinotes

Stud Length Requirements

Posted on 9-May-2016 by mathscinotes

I usually use 92 5/8" studs when I am building standard 8' tall walls – they sit sit in piles at my nearby lumber yards next to piles of 8' long studs. I recently saw (example) that there are three pre-cut sizes available:

92-5/8" : used for 8' ceiling heights
104-5/8" : used for 9' ceiling heights
116-5/8": used for 10' ceiling heights

In this post, I thought I would take a look at these pre-cut sizes to (1) learn why these values are used, and (2) to decide if any of them would be appropriate for my building activities. Continue reading →

Posted in Construction | 6 Comments

Interior Non-Load Bearing Wall Construction Methods

Posted on 6-May-2016 by mathscinotes

I am an hobbyist carpenter who is about to do some wall building. I was reading a forum discussion on the best way to build a non-load bearing, interior wall as part of a remodeling situation. The forum conversation was very thoughtful, but no real conclusions were reached. This makes sense because each forum contributor was making assumptions about the construction conditions – the construction conditions dictate which method would be "best." Continue reading →

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All In A Day's Work on Puget Sound

Posted on 5-May-2016 by mathscinotes

Quote of the Day Give me six hours to chop down a tree and I will spend the first four sharpening the axe. — Abraham Lincoln. This quote reminds me how important preparation is to the success of any endeavor. … Continue reading →

Posted in Personal | Comments Off on All In A Day's Work on Puget Sound

Simple Chip Cost Model Using Mathcad and Excel

Posted on 4-May-2016 by mathscinotes

I recently was asked by some staff members to describe the key variables that drive integrated circuit costs. To answer the question, I decided that the best approach was to prepare a spreadsheet that includes all the critical parameters along with some computational examples – people can try different parameters and determine the critical cost sensitivities on their own. Continue reading →

Posted in Electronics | Comments Off on Simple Chip Cost Model Using Mathcad and Excel

Use of AC Voltage Provides Corrosion Resistance

Posted on 3-May-2016 by mathscinotes

Some of the most vexing problems I have dealt with in my career are related to connector corrosion problems. While corrosion can create a hard failure (easy to find), more often it creates an intermittent failure (hard to find). Intermittent failures can be very expensive to find. For example, the automotive industry spent years dealing with intermittent connector problems that were caused by fretting. Continue reading →

Posted in Electronics | 3 Comments

Why Positive Ground in Telcom Power Systems?

Posted on 2-May-2016 by mathscinotes

Today, we use wires with excellent insulation and these moisture-induced corrosion arguments carry less weight. Back in the old days, however, telecom wiring had cloth-based insulation that would get wet – along with the copper wire. When you mix water and electric fields, you get electrochemical action (i.e. electroplating). While the early systems were configured with negative grounds (i.e. ground as the lowest potential in the system), it was soon discovered that these systems suffered from corrosion. Positive ground (i.e. ground is the highest potential in the system) voltages were found to be effective in combating this corrosion. Continue reading →

Posted in Electronics, Telephones | 4 Comments

Quick Look at Recent Meteor Events

Posted on 25-April-2016 by mathscinotes

I filter my news feed for anything related to astronomy, and I have been seeing a number of articles recently about large meteor explosions (called fireballs or bolides) in the atmosphere (example, example). These events are not occurring more frequently than before – we now have the technology to discover these explosions. The recent spate of bolide burst reports has caused me to become curious about how frequently these impacts are occurring. It turns out that NASA has an excellent set of web pages on this topic. There have been quite a few large meteor explosions, with the largest being the Chelyabinsk burst in 2013. As you can see in Figure 1, the cataloged meteor events are fairly even spread across the Earth. Continue reading →

Posted in Astronomy | 1 Comment

Nonlinear Piecewise Function for Stellar Luminosity vs Mass

Posted on 19-April-2016 by mathscinotes

A reader mentioned to me that the Wikipedia has an good article on stellar luminosity versus stellar mass– the article is a good one. I thought I would compare the empirical relationship shown in the Wikipedia with a couple of different data sets that I found on the web. I was motivated to perform this analysis because: (1) I have been doing some reading on exoplanets, and luminosity is important when it comes to exoplanet temperature; and (2) I am presenting a seminar on Mathcad to our engineering staff, and this application provides me a nice demonstration on how to compute nonlinear piecewise functions. Continue reading →

Posted in Astronomy, General Mathematics | 1 Comment

Ice is Almost Out at My Cabin

Posted on 18-April-2016 by mathscinotes

I love this time of year in Minnesota. I have setup cameras around my cabin in northern Minnesota so that I can see what is going on up there. I have been watching my lake go through the entire thaw process – it is almost clear of ice (Figure 1). I plan on being up there quite a bit this summer. Continue reading →

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Exoplanet Revolution Period About a Dwarf Star

Posted on 15-April-2016 by mathscinotes

In this post, I look at the habitable zone around stars smaller than our Sun and the orbital radii and periods of potentially habitable exoplanets (i.e. having temperatures near that of Earth). Continue reading →

Posted in Astronomy | 3 Comments