Days Postings
August 2024 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 31 Blog Series
Copyright Notice
© Mark Biegert and Math Encounters, 2024. 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.
Disclaimer
All 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
Circuit Worst-Case and Extreme Value Analysis
Electrical engineers design their circuits to work under "worst case" conditions. This means that the circuits will meet their operational requirements when built with any possible mix of components and environmental conditions (Figure 1). Determining the worst case conditions for a complex system can be difficult, especially for analog systems. There are numerous approaches to worst-case circuit analysis. One approach that I use is called Extreme Value Analysis (EVA). Continue reading
Posted in Electronics
1 Comment
Generating Pejsa's F Function
I have had several people ask me to review how Pejsa generated his F function. Recall that Pejsa's approach is based on using a parameter called the ballistic coefficient (BC) to scale the performance of a reference projectile – Pejsa used the US military's 30 caliber M2 bullet, which dates back to the Springfield rifle. This effort involves basic curve fitting, and I will illustrate the process for the velocity interval from 1400 feet per second (fps) to 4000 fps. This velocity range is the most important to most folks and it illustrates the basic curve fitting process well. Continue reading
Posted in Ballistics
3 Comments
Greenland Ice Sheet Trivia
I was reading an article today that says that geophysicists have figured out why the Greenland has been experiencing a flurry of magnitude 5 earthquakes. The scientists claim that the earthquakes are being caused by massive icebergs calving off the Greenland ice sheet in a manner that momentarily jams the movement of the ice sheet. The ice sheet and the calved iceberg are so massive that their interaction cause an earthquake.
While the earthquake information was interesting, there was a side discussion on the amount of ice required to raise sea level by 1 mm and seal level impact potential of a melting Greenland ice sheet. Continue reading
Posted in Geology
Comments Off on Greenland Ice Sheet Trivia
Owl Camouflage
I saw these two pictures today and I was stunned by the effectiveness of an owl's camouflage. I occasionally see owls – there is a great horned owl that lives near my house and it is amazing watching it fly at dusk. It has a very large wingspan. Continue reading
Posted in General Science
Comments Off on Owl Camouflage
Lignum Vitae is a Remarkable Wood
I enjoy woodworking very much and I am now in the process of making a solid walnut countertop by gluing small walnut pieces together. While choosing the wood species for my countertop, I did consider a number of tropical species like teak and ipe. During this search, I heard a person mention that Lignum Vitae was the world's densest wood and is known for being so oily as to be considered self-lubricating. It is also a rare and potentially endangered species. Continue reading
Posted in Construction
1 Comment
Barycenter of Pluto and Charon
I am excited about the New Horizon's flyby of the Pluto system (Figure 1) occurring on July 14, and I will be glued to my computer as the data is returning. Fortunately, there is already some data coming back on Pluto and its moons. One interesting aspect of the Pluto system is the fact that the mass ratio of Charon to Pluto is large enough that the barycenter of their orbit is outside the bodies of both Charon and Pluto. Continue reading
Posted in Astronomy
9 Comments
Volt-Ampere Measurement Circuit
This is a circuit designed by Stephen Woodward that I saw years ago in EDN. I originally was interested in the right-hand side of the circuit, which measures the real power usage of the load. I now have an interest in the left-hand side of the circuit, which measures the Volt-Ampere (VA) usage of the load. I will present an abbreviated analysis of the circuit Continue reading
Posted in Electronics
Comments Off on Volt-Ampere Measurement Circuit
Sun's Galactic Orbital Speed
I was reading Quora this week and I saw the following statement that mentioned the orbital speed of the Sun as it revolves about center of the Milky Way. Continue reading
Posted in Astronomy
Comments Off on Sun's Galactic Orbital Speed
Schmitt Trigger Circuit For a Push-Pull Output
I previously wrote a blog post about how to select components for a Schmitt trigger circuit using a comparator with an open-collector output. An engineer stopped by my cube yesterday and asked if I could write-up the same analysis for a Schmitt trigger circuit using a comparator with a push-pull output. This post will provide that analysis. The only thing unusual about the circuit is the use of a Zener diode as a voltage reference instead of the more commonly seen resistor divider network. Continue reading
Posted in Electronics
2 Comments
Number of Photons Per Second from a One-Watt Bulb
An article on Stumbleupon and called "8 shocking things we learned from Stephen Hawking's book" considered the following statement from The Grand Design shocking.
A 1-watt night-light emits a billion billion photons each second. Continue reading
Posted in General Science
Comments Off on Number of Photons Per Second from a One-Watt Bulb