Category Archives: General Science

How many people have been born over time?

Posted on 5-October-2014 by mathscinotes

I have been reading "Time Reborn" by Lee Smolin and it has been a very informative read. In the book, Lee Smolin mentions that there have been 110 billion humans born over time. I found this number interesting and I … Continue reading →

Posted in General Science | 3 Comments

Quick Look at Low Sodium Cereals

Posted on 17-September-2014 by mathscinotes

Quote of the Day Success consists of going from failure to failure without losing enthusiasm. — Winston Churchill Since I have identified that my current ready-to-eat breakfast cereal has too much salt (blog post), I need to find a low-salt … Continue reading →

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There Appears to Be No Limits to Stereolithography

Posted on 5-September-2014 by mathscinotes

I have been using stereolithographic assembly (SLA) since the early 1990s. In the early days, the prototypes we generated were a bit crude but still useful. For example, in one time-critical situation, we needed a tail cone for an underwater vehicle ASAP and we generated a plastic prototype that we used to make a mold for the final aluminum version. It took a couple of days and we had an aluminum tail cone that worked great. Continue reading →

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Is a Part's Technology a Step, Stretch, or Leap?

Posted on 27-August-2014 by mathscinotes

The most secure type of part is one that is manufactured to an industry standard and is made by multiple vendors. Unfortunately, products that use only multi-source, standards-based parts will not give you any advantage in the marketplace. To be able to build a profitable product in volume reliably, you must apply enough new technology to give you a marketplace advantage while maintaining an acceptable level of component supply risk − balance is everything. Continue reading →

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Budgeting for an Air Conditioner

Posted on 20-August-2014 by mathscinotes

I just recently added 20 kW of capacity electrical capacity to the lab. Other lab users have probably added another 20 kW of electrical capacity to the lab. Since I am conservative by nature, I will assume that all this electrical power is going to be used and will end up as heat dissipated in the lab. So I am estimating that we have added 40 kW of heat load to the lab, which means I should provide sufficient air conditioning capacity to cool that load (Figure 1 shows a common type of commercial, roof-top, air conditioner Continue reading →

Posted in Construction, General Science | 1 Comment

It's Warm Out and the PVC is Getting Longer ...

Posted on 20-June-2014 by mathscinotes

I live in Minnesota -- where winter temperatures can be as low as -36 °C (-33 °F) and summer temperatures can be as hot as 38 °C (100 °F). Because most things expand when our days get hotter, we occasionally have things like doors and windows that are too tight in the summer and too loose in the winter. Today, I encountered a PVC pipe that was installed during the heat of last summer and it had ripped itself free of its mounting brackets during the cold of winter. Of course, it is summer now and the pipe is back to its installed length. I was asked by an electrical equipment installer today how much length variation should he plan for when using PVC pipe outdoors. It turns out the National Electrical Code (NEC) actually has a table that addresses this question and I will discuss in this post how that table was generated. Let's discuss the answer I gave this installer. Continue reading →

Posted in Construction, General Science | 2 Comments

Population Occurrence Frequency Math

Posted on 8-March-2014 by mathscinotes

Quote of the Day Do what you can, with what you have, where you are. — Theodore Roosevelt I was reading an article on autism and the article mentioned that autism is much more prevalent in boys than girls. This … Continue reading →

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Heavy Water Ice Cubes Do Not Float

Posted on 23-February-2014 by mathscinotes

Quote of the Day The problem with object-oriented languages is they’ve got all this implicit environment that they carry around with them. You wanted a banana but what you got was a gorilla holding the banana and the entire jungle. … Continue reading →

Posted in General Science | 14 Comments

Lead Paint Math

Posted on 12-February-2014 by mathscinotes

I shudder to think of the Romans using lead acetate as a food sweetener. Our use of lead as a gasoline additive, which put lead into the air, was probably not very health either. I saw a blog post where a construction worker was asking about how much lead there is in one square foot of painted wall surface. I thought it would be worthwhile to work this number out. Continue reading →

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Minnesota Winter Turns a Corner This Time of Year

Posted on 22-January-2014 by mathscinotes

We are going through a some very cold weather now in Minnesota. During late January, I start to daydream about warm weather. While daydreaming about going to my lake cabin today, I started to wonder when the average daily temperature … Continue reading →

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