Category Archives: General Science

Volume Reduction in Ethanol-Water Mixtures

I recently toured a winery and, during the tour, I saw a number of charts related to various properties of ethanol and water mixtures. I was a bit puzzled when I saw Figure 1, which is a chart that I had never seen before. Figure 1 shows the amount of volume reduction experienced by an ethanol-water mixture compared to the separate volumes of the water and ethanol. I became curious about the chart and decided to see if I could derive these results on my own. Continue reading

 
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CO2 Tonnage Added To Atmosphere Per Year

My youngest son told me that I needed to watch the new Cosmos series with Neil deGrasse Tyson. I was immediately hooked – it is a masterpiece of scientific exposition for a general audience. I thought the original Cosmos with Carl Sagan was excellent, but the progress in computer graphics during the intervening decades makes the program visually stunning. Continue reading

 
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Converting Specific Humidity to Relative Humidity

I often have to interpret odd test requirements. In a test specification based on GR-487, a humidity test is called out where we need to have a fixed specific humidity (i.e. 24 grams of water vapor per per kilogram of air). For a given specific humidity, the relative humidity will vary with temperature. Since my test gear can control relative humidity, I need to derive a relationship between relative humidity and the specific humidity, which I show in Figure 1. Continue reading

 
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Nuclear Spent Fuel Annual Generation Rate

A coworker was telling me about a relative of his who is an engineer at a nuclear power plant. One of his relative's many jobs is to babysit nuclear waste casks (Figure 1) – a task which includes monitoring their temperature. These casks are warmed from the inside by the radioactive decay of the waste they hold. As I understand it, this job has good long-term security because these casks are going to be a safety hazard for tens of thousands of years. Continue reading

 
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Power Plant Conversion Efficiencies

While crawling around the Energy Information Administration (EIA) web page, I found some data on the energy conversion efficiencies of power plants based on the fuel that they use. I thought the data was interesting and worth going through here. Continue reading

 
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Lessons from RP Feynman

There is almost a cottage industry in RP Feynman quotes and stories. For an engineer, there is much gold to mined in his problem-solving methods. I read his book Surely You're Joking Mr. Feynman, and I have treated him as source of inspiration ever since. I was drawn to the joy he expressed about solving problems, and his skill in sharing that joy. Continue reading

 
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A Mathcad Utility Function for Air Pressure and Density

I have some work to do that requires a model for air density as a function of altitude, temperature, and pressure. As usual, I will turn to the Wikipedia to provide me a working model. I will then check the results of my model against results published by other sources. Continue reading

 
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Network Availability

I was in an interminable meeting the other day where we were discussing the MTBF and availability of a system. My issue with this discussion is that each person in the room preferred to think about these terms in different ways. In this post, I will show that the four individuals in the meeting were actually in violent agreement and simply did not understand that what their arguments were mathematically equivalent. I wish I could say that this was the first time in my career that this had happened, but that would not be true. It happens all the time. Continue reading

 
Posted in Electronics, General Science | 4 Comments

Modeling Coal Energy Output

I had never seen coal until my first trip to China when I saw people on bicycles transporting coal to their homes for heat. I started to wonder just how much coal a home would need for heating. I have seen numerous values for the heat content of the various types of coal. I recalled from primary school that there were three types of coal: anthracite, bituminous, and lignite. So I would have expected three values for the heat output of coal. When I actually looked, I found dozens of grades of three primary types of coal. Each of the different grades would generate different amounts of heat per kilogram. I thought I would take a closer look at how the heat output from coal could be modeled using regression and a simplified model based on chemical heats of formation. Continue reading

 
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Mass-Energy Conversion Example

Since 2015 is the 70th anniversary of the end of World War 2 (WW2), C-SPAN has been running a number of oral history interviews with people who worked on the Manhattan Project. I have found these interviews very interesting. You can find them on YouTube and watch them for yourself. Continue reading

 
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