General

Three men were abducted by aliens. A mathematician, a physicist, and an engineer.

When they woke up, they were on one side of a room, and on the other side was a beautiful blonde with a pistol beside them.

A disembodied voice says, “You are allowed to move half the remaining distance across the room each time you move. If you can make it to the other side, you can do what you will with the blonde, and you will be set free. If you don’t make it to the other side, you can either kill yourself or be taken for the probings.”

The mathematician sits and thinks for a little, calculates a bit more, then says, “It is impossible; no matter how many steps you take, there will still be more to go.”

With that, the mathematician picks up the gun and shoots himself.

The engineer and physicist sit in shock for a moment before the physicist speaks up.

“You know that mathematicians are stuck in their numbers. They have no real-world experience. I’m going to test his hypothesis.”

So he does; on the first move he makes it halfway, on the second he is 3/4s of the way, and on the next move he’s 7/8s. He’s making progress, but he realizes he will never make it all the way.

He returns to his side of the room, picks up the gun, and offs himself.

The engineer is nearly in shock. He looks at the two bodies and then gathers himself up. He starts the process of crossing the room.

After over 50 moves, he reaches out, grabs the blonde, yanks her into his arms, and says, “Good enough for all practical purposes.”

For All Practical Purposes

During the age of steam, engineers developed a working idea of how steam engines worked and how to measure them. These men were not dumb; they understood nature, and they understood Newtonian physics. They developed formulas to guide them as they designed new engines.

What were they interested in? They wanted an efficient engine that produced enough work to make it worthwhile.

What is efficiency in a steam engine? How much steam it consumes. A boiler is only capable of producing a limited amount of steam. That is based on the amount of heat put into the system along with how efficient the boiler is at transferring the heat into water to force a phase change.

The more efficient the boiler, the less fuel it took to run. Coal and wood cost money.

An inefficient steam engine consumes more steam, which requires the boiler to produce more steam, which means more fuel.

The work that an engine produces is defined as brake torque and brake horsepower. Torque is how much rotational force is being produced, while horsepower is force of distance. Steam engines produce good torque over the entire range of supported speeds.

They had methods of measuring torque and horsepower. They could also measure the pressure of the steam. They knew the size of the piston they were using. They needed an expression for determining torque and horsepower before they designed an engine, much less built it.

The formula was P.L.A.N., which is pressure times length of stroke in feet times area of the piston face times the number of power strokes per minute.

They can easily measure stroke length, piston area, and power strokes per minute; those are simple things that can be measured with a ruler and a counter over time. But how do you measure the pressure?

The pressure changes over the time of the power stroke. At the start of the stroke, the cylinder has not yet filled with steam; it is still entering, so it is lower than the source. As the cylinder begins to fill, the piston starts moving, increasing the volume while reducing the pressure. The cutoff takes place, and now no more steam is being allowed to enter, and the steam that is there just expands, decreasing the pressure even more.

At every moment of that cycle there is a different pressure in the cylinder. With advanced math, you might be able to calculate it at every step then integrate over time.

These guys stuck some sort of pressure gauge on the cylinder and somehow measured the average (mean) pressure.

This is the value they used. The Mean Effective Pressure or MEP.

This is good enough for all practical purposes.

What is the starting pressure

If you have a closed system, the pressure at every point is the same. A steam engine is not a closed system. There is always steam being vented to the outside, either directly to the atmosphere or into a condenser.

This produces a sequence of pressure drops. The pressure is then built up as new steam flows from the boiler. All of this happens very rapidly, but it does take time. To reduce the amount of pulsing that hits the boiler, we use a steam reservoir, which is part of the steam chest.

When the flow of a fluid is stopped rapidly, it causes a “hammer” effect. Opening and closing the valves, allowing steam to flow into the cylinder and then stop can do just this.

The following video explains the water hammer phenomenon.

By putting that reservoir closer to the valves, we can stop that phenomenon from hammering on the boiler.

But how do we know what the pressure is in the steam chest? We might assume it is the same as the boiler, but it takes time for the steam chest to fill. The amount of time it takes to fill and stabilize is dependent on the size and shape of the piping from the boiler to the steam chest.

We need to measure or otherwise determine what the effective pressure in the steam chest is.

So we have a basic idea of what the pressure might be.

How much does it cost

Steam travels from the steam chest into the cylinder via a steam passage. The shape, wall texture, and size of the steam passage affect the speed at which the steam enters the cylinder. In addition, we have the mass of the fluid (air/steam) that is in the passage when we start pressurizing it.

We need to measure how long it takes to reach the cylinder port and how long it takes to fill the cylinder. The smaller the passage, the more velocity you lose and the longer it takes to fill the cylinder. If it takes longer to fill the cylinder than the admission stage of the cycle then we are not getting full power from the engine.

Sometimes these passages are drilled and plugged or covered. Other times they are cast into the cylinder body. If cast, the quality of that core determines the texture/smoothness of the walls of the passage. Other times, they are drilled in a straight line to intersecting passages. Regardless of how they are made, they are a complex shape that causes turbulence and can cause other issues.

We need to know how much we lose, the cost, of getting steam from the steam chest into the cylinder.

And what happens in the cylinder

As stated before, the cylinder volume is constantly changing. The volume is decreasing when we start allowing steam into the cylinder. This lead steam acts like a cushion or spring to help start the piston back in the other direction. Remember that we are not only using energy to create power/work, we are also using energy to reverse the direction of the cylinder.

With a standard 4 stroke engine, we have four stages: Intake, where we suck a fuel air mixture into the cylinder. Compression, where the fuel air mixture is compressed for maximum efficiency. The power stroke, where the fuel has burned and the expanding gas is driving the piston. Finally, we have the exhaust stroke, where the expended gases are pushed out of the cylinder.

Only the power stroke puts energy into the system. The other three strokes are wasted. The energy to move the piston comes from other cylinders or energy stored in a flywheel.

With the steam engine, as the volume is decreasing, the expended steam is being pushed out the exhaust port. In simple engines the exhaust port is the same as the inlet port. Just before top dead center, steam is allowed back into the cylinder, pushing against the piston. This slows the piston as it reverses direction. The steam pushes the piston away from the cylinder head, causing the volume to increase.

Before we reach bottom dead center, the inlet is cut off. The steam continues to expand, continuing to push on the piston. Finally the piston reverses direction, and the used steam is exhausted to the atmosphere.

We need to integrate the pressure at the surface of the piston over the entire cycle.

Computational Fluid Dynamics (CFD)

I have studied Finite Element Methods (FEM). CFD is a different from FEM but has many similar aspects. The gist is that we create a mesh of a volume. We set the initial conditions of every surface or point. The initial condition is the pressure and a velocity vector.

We then define some formulas that describe how the fluid acts. From this we propagate the initial conditions through the mesh to a “stable” result. We can then use that result as a new set of initial conditions and iterate another time step.

With this we can see pressure waves, velocities, and just about everything we need to know about the flow of the fluid through the mesh.

The great thing is that there are good, free CFD packages out there. I’m using OpenFOAM because I am using FreeCAD as my modeling software.

With FreeCAD you can build a “body” or “part”. A part is a single item. It can be created by additive or subtractive means. It could be a rough or machined casting or something made from bar stock.

The bodies are combined into “assemblies”. An assembly is a collection of parts that are connected with joints. Joints can be fixed, sliding, rotating, and a few others.

I’ve been able to take the parts of the steam engine I’ve modeled and create assemblies, which have shown me that I misread the prints. Meaning I’ve had to go back and redo the body/part which sometimes required redoing the assembly. An iterative process.

With a body, I should be able to create a negative of that body, representing the domain of for the CFD, which is what gets meshed.

I can use the CfdOF workbench to create meshes, set initial conditions, set the properties for the fluid, refine the mesh, and a dozen other things before passing the actual analysis off to OpenFOAM.

OpenFOAM runs for a long time and then produces results that I should be able to visualize. That has not been working all that well.

From this, I should be able to calculate what MEP is at every location and step of the system.

And I’m stuck here. Not totally stuck, but more of the I know I don’t know something, I’ll have to figure it out.

But what about the rest

All of the above is just to get a cylinder that will produce the power I need or want.

From there we move into the mechanical world. Here we have to design the components to meet the requirements of the cylinder.

How big should the piston rod be? It has no rotational or angular forces applied to it, just tension and compression. This is an FEM calculation or uses simple analytical calculations.

The connecting rod gets more complex. The big end is connected to the crankpin, which moves in a circle. The small end is attached to the end of the piston rod. It moves in a linear motion. We need to evaluate the forces in play on the crosshead pin and the crankpin to make sure they are strong enough but not overkill. We need to design for reduced mass because mass changing directions takes energy.

We also have to worry about the vibrations we get from throwing the crankpin in a circle.

If you want to design a vibrating thing, just put a weight off-center on a spinning thing, and you get vibrations. We balance the wheels of our cars to remove that type of vibration. We have to balance the crank to remove as much of the vibration as possible.

But we have to know what the forces in play are at every stage of the cycle to know how to cancel them. Painful.

We need to know the size of the driveshaft. My small models use a 1/4 inch shaft. For my 1/2 HP engine, I doubt a 1/4 will be strong enough.

The shaft must ride in bearings that can withstand the reciprocating forces as well as the axial forces.

But why?

The answer is never simple, but for me I want to be able to enter a desired HP rating and torque rating and have a custom designed steam engine modeled.

I currently have an integrated spreadsheet with my 3D model. You can select or set the desired brake power you want at a given boiler pressure and a given RPM. This feeds into several formulas, which then drive the model.

Change the stroke in the spreadsheet, and everything from the cylinder through the final assembly changes to match that cylinder. It even goes so far as to define the number of screws or bolts in the cylinder flange, the size of those screws and bolts, as well as the proper torque values for those screws and bolts.

The next step is to get the steam passages correctly designed and sized. This will drive the steam chest which will drive other components.

In the end I should be able to have the system give me patterns for casting.

For some reason last year moved more rapidly than I expected. There are so many things I didn’t get done that I needed to. Yet we are here.

The big thing to me is how the culture battle changed.

2 years ago, I would not have imagined talking about birthright citizenship. We all knew that whelping a baby on American soil meant another anchor baby, another family of immigrants, and another strain on our resources. Today we are arguing if there is such a thing as birthright citizenship for illegal aliens.

2 years ago, I would not have imagined we would be talking about massive ICE enforcement actions. Today we are talking about over a million illegal aliens who have self deported.

2 years ago, I would not have imagined we would be actually fighting a war on drugs. Today we are arguing about due process for narco terrorists that have just been blasted out of existence.

2 years ago, I would not have imagined peace breaking out in so many places. Today we are arguing about a ceasefire being broken while the peace is happening in so many places.

A year ago I was hoping for an end to the war in Ukraine. Today I see that we are no longer sending dollars, but we are supporting.

Finally, a year ago I knew that there was corruption in my government. I knew money was being wasted by the millions. Today I’m watching massive fraud being detected, and it looks like action is being taken.

It was a good year.

We wish you and yours a wonderful new year. We are glad you are hear.

Here’s a long debate. Charlie vs. 25.

From Rebecca Harvey on Facebook:

She thought she was studying milk. What she uncovered was a conversation. In 2008 evolutionary anthropologist Katie Hinde was working in a primate research lab in California, analyzing breast milk from rhesus macaque mothers. She had hundreds of samples and thousands of data points. Everything looked routine until one pattern refused to disappear.

Mothers raising sons produced milk richer in fat and protein. Mothers raising daughters produced a larger volume with different nutrient balances. It was consistent. Repeatable. And deeply uncomfortable for the scientific consensus.

Colleagues suggested error. Noise. Statistical coincidence. But Katie trusted the data. And the data pointed to a radical idea. Milk is not just nutrition. It is information. For decades biology treated breast milk as simple fuel. Calories in, growth out. But if milk were only calories, why would it change based on the sex of the baby? Katie kept going.

Across more than two hundred fifty mothers and over seven hundred sampling events, the story grew more complex. Younger first time mothers produced milk with fewer calories but significantly higher levels of cortisol, the stress hormone. The babies who drank it grew faster. They were also more alert, more cautious, and more anxious. Milk was not only building bodies. It was shaping behavior.

Then came the discovery that changed everything.

When a baby nurses, microscopic amounts of saliva flow back into the breast. That saliva carries biological signals about the infant’s immune system. If the baby is getting sick, the mother’s body detects it. Within hours the milk changes. White blood cells increase. Macrophages multiply. Targeted antibodies appear. When the baby recovers, the milk returns to baseline. This was not coincidence. It was call and response. A biological dialogue refined over millions of years. Invisible to science until someone thought to listen.

As Katie surveyed existing research, she found something disturbing. There were twice as many studies on erectile dysfunction as on breast milk composition. The first food every human consumes.
The substance that shaped our species. Largely ignored. So she did something bold. She launched a blog with a deliberately provocative name, Mammals Suck Milk. It attracted over a million readers in its first year. Parents. Doctors. Researchers. People asking questions science had skipped. The discoveries kept coming. Milk changes by time of day. Foremilk differs from hindmilk.

Human milk contains over two hundred oligosaccharides babies cannot digest because they exist to feed beneficial gut bacteria. Every mother’s milk is biologically unique.

In 2017 Katie brought this work to a TED stage. In 2020 it reached a global audience through the Netflix series Babies. Today at Arizona State University’s Comparative Lactation Lab, Dr. Katie Hinde continues shaping how medicine understands infant development, neonatal care, formula design, and public health. The implications are enormous.

Milk has been evolving for more than two hundred million years. Longer than dinosaurs walked the Earth. What we once dismissed as simple nutrition is one of the most sophisticated communication systems biology has ever produced. Katie Hinde did not just study milk. She revealed that nourishment is intelligence. A living responsive system shaping who we become before we ever speak. All because one scientist refused to accept that half the story was measurement error.

Sometimes the biggest revolutions begin by listening to what everyone else ignores.”
– thanks Dale McElroy

Read More

I’ve been having difficulty “doing” things in my office. Two big reasons: one, it is freaking cold. The other, optics.

Our basement is unheated, and we lose way to much heat through the floor into the basement. One of the things that I need to do is to make sure the basement is properly sealed and then to look into insulating it a bit.

With dead shoes, my feet were cold. My hands were cold. My head was cold. It isn’t uncommon to enter my office, which is isolated from the woodstove-heated parts of the house, to see 52° on the thermometer. I have a silent oil-filled heater. Over the course of about an hour the temp will come up to around 63°. On a good day, it might climb over 65°.

That issue was mostly solved by good, fur-lined moccasins.

What I didn’t realize was that my optics were failing me.

Back in the 80s, while at university, I would drive my friend around to different places because he was legally blind. He would tell me street names from memory. And I would miss turns all the time.

It took a couple of trips before I found the right place to turn. I had to find landmarks. I was not driving by street names; I was driving from landmark to landmark.

If you want the epitome of this, just ask a New Englander for directions: Turn left on School Street; it is just past where the machine shop used to be. Yeah, I’ve become that guy.

Regardless, I knew where I was but couldn’t name the street I was on. Then I did something weird: I got my eyes examined and new glasses.

Suddenly I was driving by street names. Why? Because I could actually see the damn street signs before I was driving past them.

Well, my prescription for driving appears to be good. My progressives are not. I need new glasses.

How does this affect working at my computer? Umm, I’m embarrassed to admit, but I put on my computer glasses tonight to see if it makes a difference.It does. I can actually read what’s on the screen.

So when we are talking about optics, remember that they start with the optics that you wear on your face.

…and to all, a good night!

It isn’t often you get to compare your writing with that of your father and grandfather. My grandfather was a PhD with published works. I should try to find his thesis and other publications. I have read his unpublished autobiography.

My father had a few articles published, and I’m sure he wrote more. I should attempt to get his master’s thesis from ODU.

Yesterday my daughter stumbled onto a couple of articles published by my father. I write like he did. I guess I speak like he did as well.

I’m positive that much of my very dry humor comes from him.

His layout was what was known as an “operational” layout. This meant that you could run it realistically. He had cards that represented loads and destinations. The yard operators would have to make up trains, which would then be moved over the main line to different yards by other operators.

Still other operators would run the locals. These were the little trains that went to the different businesses to pick up and drop off loads.

A standard operating session would be 7 or more operators working over 3 hours on a 6:1 fast clock. In other words, they would simulate 18 hours of operations in just 3 hours. Generally, was made up by the fact that the locations did not have real distances between them. So the dairy was only a 1/2 mile from the yard, while it was more like 6 miles in reality.

Regardless, I love and miss Dad. If you feel like it, go read his entire article. He has pictures and more.