# Monthly Archives: January 2015

## PVC Expansion and How to Deal with it

I have written a post about the problems that I encounter with the improper use of PVC pipes and accessories in outdoor Fiber-To-The-Home (FTTH) deployments. During my normal reading about codes and regulations, I found an example of a bad installation and an example of how to properly deal with PVC expansion by installing an expansion joint. Both of these items deserve some coverage here. Continue reading

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## Ship's Course Correction for Cross-Current Rule of Thumb

I have lived most of my life in Minnesota, which is about as far away from the oceans as you can be in the United States. The idea of a planet mainly covered with water has always fascinated me. I will never forget the first time I saw an ocean (Pacific, Santa Monica, CA 1982). Fortunately, my work has provided me a bit of experience on ships and that experience was career changing − my early ocean experience involved laying fiber optic cable and that set the course of the rest of my career. Continue reading

Posted in Naval History, Navigation | Comments Off on Ship's Course Correction for Cross-Current Rule of Thumb

## Donor Chain Math

I just read an interesting article at Ars Technica on the mathematics behind setting up donor chains. The math is actually a variant of the prize-collecting traveling salesman problem, which is NP-hard. Continue reading

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## Mississippi River and Its Distance from the Center of the Earth

In a recent post, I discussed how to compute the distance of mountaintops from the center of the Earth. This computation was interesting because we had to take into account the oblate shape of the Earth. Continue reading

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## My Online Statistics Education Experience

Quote of the Day I can't mate in captivity. - Gloria Steinem on why she never married I have been fortunate in having worked for companies that have had enlightened education policies, which I have always taken advantage of. These … Continue reading

Posted in Statistics | 3 Comments

## Super-Strong Sawhorse

Quote of the Day How far you go in life depends on your being tender with the young, compassionate with the aged, sympathetic with the striving, and tolerant with the weak… because in your life you will have been all … Continue reading

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## High-Speed Broadband, Fiber-To-The-Home, and President Obama

Quote of the Day Even if all others do - not I. — Father of Joachim Fest (German Historian), from the Gospel of Matthew, a quote he made his sons memorize during WW2. I have been working for the past … Continue reading

Posted in Fiber Optics | 2 Comments

## Beautiful Spiral

Quote of the Day If a mistake is not a stepping stone, then it is a mistake. — Eli Siegel, "Damned Welcome" I have always been amazed at the beautiful curves that relatively simple functions can generate. I saw this … Continue reading

Posted in Electronics, Geometry, Humor | Comments Off on Beautiful Spiral

I am not a cat person – the only time that cats come up in my family is in regards to Schrodinger's cat (Figure 1). However, I just came across an interesting web page by the Oak Ridge Associated Universities that discusses cat litter and the fact that it is slightly radioactive. Some cat litter is slightly radioactive because the contain bentonite clay, which contains small amounts of radioactive uranium (238U), thorium (232U), and potassium (40K). I find this web page interesting because it includes measured radiation data and an estimate of the heavy metals (uranium and thorium) that are contained in cat litter. Continue reading

Posted in General Mathematics, General Science | 4 Comments

## Dating and Compatibility Correlations

There must be an enormous amount of money involved in Internet dating because I see their commercials on television all the time. As far as their success in matching people up, I only have one data point – one of my sons met a wonderful gal though the OkCupid online service. Continue reading

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