Energy Storage

Posted by PITHOCRATES - September 18th, 2013

Technology 101

Our First Energy Storage Devices helped us Kill each other in Battle

There’s something very important to today’s generation.  Stored energy.  It’s utmost on their minds.  As they are literally obsessed with it.  And get downright furious when they have none.  Because without stored energy their smartphones, tablets and laptop computers will not work.  And when they don’t they will disconnect them from the Internet.  And social media.  A fate so horrible that they carry spare batteries with them.  Or a power cord to plug into an electrical outlet or cigarette lighter in a car.

Energy storage devices go back millennia.  Of course, back then there was no Internet or social media.  People just talked to each other in person. Something unimaginable to today’s generation.  For it was a simpler time then.  We ate.  We procreated.  Sometimes talked.  And we killed each other.  Which is where that energy storage comes in.

An early use of energy storage was to make killing each other easier.  Early humans used rocks thrown by slings and spears thrown by hand in hunting and war.  But you had to get pretty close to your prey/enemy to use these things.  As the human body doesn’t have the strength to throw these things very far or hard.  But thanks to our ingenuity we could use our tools and make machines that could.  Such as the bow and arrow.

The Bow and Arrow and the Crossbow use Tension and Compression to Store Energy

We made early bows from wood.  They had a handgrip and two limbs, one above and one below the handgrip.  Attached to these limbs was a bowstring.  The limbs were flexible and could bend.  And because they could they could store energy.  The archer would draw back the bowstring, bending the two limbs towards him.  This took a lot of strength to bend this wood.  The farther the archer pulled back the bowstring the more strength it took.  Because it was not the natural state for those limbs.  They wanted to remain unbent.  And were ready to snap back to that unbent position in a fraction of a second.  Much quicker than the archer pulled back the bowstring.

As the limbs bent the inside of the limb (towards the archer) was under compression.  The outside of the limb (facing away from the archer) was under tension.  The compression side was storing energy.  And the tension side was storing energy.  Think of two springs.  One that you stretch out in tension that will snap back to an un-stretched position when released.  And one that you push down in compression that will push back to an uncompressed position when released.  These are the two forces acting on the inside and the outside of the bending limbs of a bow.  Storing energy in the bow.  When the archer releases the bowstring this releases that stored energy.  Snapping those limbs back to an unbent position in a fraction of a second.  Bringing the bowstring with it.  Very quickly.  Launching the arrow into a fast flight toward the archer’s prey/enemy.

The stronger the bow the more energy it will store.  And the more lethal will be the projectile it launches.  Iron is much harder to bend than wood.  So it will store a lot more energy.  But a human cannot draw back a bowstring on an iron bow.  He just doesn’t have the strength to bend iron like he can bend wood.  So they added a couple of simple machines—levers to turn a wheel—at the end of a large wooden beam to draw back the bowstring.  At the other end of this beam was the iron bow.  What we call a crossbow.  With the wheel increasing the force the archer applied to the hand-crank the iron bow slowly but surely bent back.  Storing enormous amounts of energy.  And when released it could send a heavy projectile fast enough to penetrate the armor of a knight.

The Mangonel uses Twisted Rope to Store Energy while a Trebuchet uses a Counterpoise

Most children did this little trick in elementary school.  The old rattlesnake in the envelope trick.  You open up a large paperclip and stretch a small rubber band across it.  Then you slide a smaller paperclip across the taut rubber band.  And then you turn that small paperclip over and over until you twist the rubber band up into a tight twist.  Storing energy in that twist.  Slip it into the envelope.  And let some unsuspecting person open the envelope.  Allowing that rubber band to untwist quickly.  With the paperclip spinning around in the envelope making a rattlesnake sound.

We call this type of energy storage torsion.  An object that in its normal state is untwisted.  When you twist it the object wants to untwist back to its normal state.  On the battlefield we used this type of energy storage in a catapult.  The mangonel.  Which used a few simple machines.  We used a lever inserted into a tight rope braid.  In its normal state the lever stood upright.  A lever turned a wheel a cog at a time to pull the large lever down parallel to the ground.  Twisting the rope.  Putting it under torsion.  Storing a lot of energy.  When they released the holding mechanism the rope rapidly untwisted sending the large lever back upright at great speed.  Sending the object on it hurling towards the enemy.

The problem with the mangonel is that it took a long time to crank that rope into torsion.  Another catapult did away with this problem.  The trebuchet.  Perhaps the king of catapults.  This was a large lever with a small length on one side of the pivot and a large length on the other side of the pivot.  Think of a railroad crossing arm.  A long arm blocking the road with a counterweight at the other end.  We balance this so well that we need very little energy to raise or lower it.  The trebuchet, on the other hand, is not perfectly balanced.  It has a very heavy counterweight—a counterpoise—that in its normal state is hanging down with the long end of the lever pointing skyward.  They pull the long end of the lever down close to the ground.  Pulling up the counterweight.  Attached to the far end of the lever is a rope.  At the end of the rope is a rope pouch to hold the projectile.  When released the counterweight swings back down.  Sending the long end of the lever up quickly.  With the far end traveling very quickly.  Pulling the rope with it.  Because the length of the rope adds additional distance to the lever the projectile travels even faster than the end of the lever.  Which is why the stored energy in the hanging counterweight can launch a very heavy projectile great distances.


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Labor Theory of Value and Prices

Posted by PITHOCRATES - May 13th, 2013

Economics 101

“Do you know how many men you and that machine are putting out of a job?”

Ditch digging is back-breaking work.  Often under a blistering sun.  Where laborers swing picks into the hard soil.  Breaking the compacted soil and rock into loose chunks.  Then another laborer thrusts his shovel into the loosened soil.  Scoops up a load and transfers it to a large bucket.  When full other laborers topside heave the bucket up from the trench.  And empties it onto a cart.  Then returns the bucket to the bottom of the trench.  Then laborers swing their picks.  And scoop up more soil.

A ditch digger may hate his job.  The immense physical requirements wearing him down.  Working in unbearable heat.  And the monotony.  Just dig, dig, dig.  Pausing to wipe the sweat rolling off his face with his shirt sleeve.  To grab a deep breath.  Or a swig of water.  Then back to the pick.  Or shovel.  Calloused hands gripping a splintered handle.  As his burning muscles drive it back into the earth.  All the while thinking that there must be a better way.

Then the day comes when a truck pulls onto site.  Pulling a trailer.  And on that trailer is the future.  A mechanical excavator.  With a 44″-wide bucket on it that can move more soil with one swipe than a laborer can dig in a day.  A machine that would revolutionize ditch digging.  As one machine and a crew of a few men could do the work of 100 ditch diggers in far less time.  As the machine operator prepares to drive the mechanical excavator off the trailer a grizzled ditch digger walks up to him and says, “Do you know how many men you and that machine are putting out of a job?”

Something is Worth what Someone is Willing to Pay for it Regardless of the Quantity of Labor

The labor theory of value would say this ditch is very valuable.  Before the future arrived on that trailer.  For this theory states that value is proportional to the quantity of labor it takes to make or do something.  The more labor hours required the more valuable it is.  It’s not the market that determines value via the laws of supply and demand.  As happens under capitalism.  No.  It’s labor that determines value.  A theory championed by labor movements.  And Karl Marx.  The father of communism.  The greatest anti-capitalist of them all.  Which reveals the true motive behind the labor theory of value.  To give more political power to labor.  While having nothing to do with economics.

To illustrate this let’s look at ditch digging.  The way it was.  And the way it is.  For this exercise let’s consider a ditch for a 60″ storm drain.  Which requires a deep, long trench.  Let’s say it takes a crew of 100 laborers to hand-dig the trench in 6 weeks.  While a crew of 10 laborers and a machine can do the job in 1 week.  Each laborer has $25 worth of tools.  And the mechanical excavator costs $25,000 to rent for one week.  Now let’s assume two construction companies put a bid together for this work.  One bases their estimate on the way it was.  Men digging by hand.  The other bases their estimate on the way it is.  Using a machine.  The value of this trench is the cost of their estimates.  That is, the value of the trench is the cost to dig it.  Which is the price someone must pay to have this ditch.  We summarize these two estimates in the following table.

Ditch Digging

The bottom line in the table is the value of the dug trench.  Which you will notice has two different values.  Even though both methods result in an identical thing.  A trench the same length, width and depth.  Yet if dug by hand the price is $1.8 million.  But if we dig it with a machine the price is $55,250.  How can this be?  How can two identical things have two different prices?  Well, they can’t.  What we have is two prices.  But only one price someone will pay.  The low price.  Because that’s all the trench is worth.  The price someone is willing to pay.  Regardless of the quantity of labor used to dig it.

The Labor Theory of Value is a Flawed Economic Theory used more to Attack Capitalism

So Karl Marx was wrong.  As are those in the labor movement.  While the capitalists were/are right.  Labor does NOT determine value.  The market does.  Something is only worth what someone is willing to pay for it.  Based on the laws of supply and demand.

For example, a lot of labor hours go into building a caboose.  The last car on a train before FRED (flashing rear-end device).  The steel wheels, the brakes, the enclosure, the wood burning stove for the brakeman to warm up by, etc.  Which gives it great value based on the labor theory of value.  And a high selling price.  But trains today don’t use cabooses.  For they have no brakemen running along the top of moving trains to turn the brake wheels to stop the train.  Thanks to George Westinghouse and his air brake.  So there is very little if any demand for cabooses by today’s railroads.  Making it all but worthless.  Despite the high price tag based on the quantity of labor used to build it.

Again, supply and demand determine prices.  Not the quantity of labor.  And you can see this anywhere you look.  Another good example is housing.  You can build identical houses in two different locations and they can sell for two different prices.  Despite being built with the exact same amount of labor.  That house on the beach in Malibu will have a far higher price than the same house in Detroit.  For when it comes to real estate three things determine the price of a house.  Location, location and location.  Regardless of the quantity of labor used to build it.  Whether 100 workers build it using nothing but hand tools.  Or a crew of 10 using the latest in power tools and equipment.  It will cost more to pay 100 men to build it using nothing but hand tools.  But it won’t sell for any more than the one built by the crew of 10 using the latest in power tools and equipment.  Because the labor theory of value is a flawed economic theory.  Used more to attack capitalism.  To transfer power from the capitalists to the labor movement.  And the unions that represent them.  As well as the government officials that protect the unions in exchange for campaign contributions.


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Wheel and Axle

Posted by PITHOCRATES - May 8th, 2013

Technology 101

The Key to the Wheel and Axle is the different Angular Velocities of the Outer Surfaces of the Axle and Wheel

Have you ever tried to turn a screw using only your fingers?  You might be able to get it started and spin it a few rotations.  But eventually you’ll be unable to turn the screw any further.  If you use a screw driver, though, you’ll be able to turn the screw all the way in.  Why?  For the same reason you can turn the handle on the spigot when you want to water the grass.  And why you can open the door when you enter your home.  Because of a wheel and axle.

The wheel and axle is one of six simple machines.  The others being the lever, the inclined plane, the pulley, the wedge and the screw.  The wheel and axle are two circular parts whose outer surfaces rotate at different speeds.  Think of a large wagon wheel.  Wooden spokes connect the outer rim of the wheel (the felloes) to the hub.  Imagine the wheel turning one quarter turn.  The end of the spoke at the felloes has to cover more distance than the end of the spoke at the hub.  Therefore the spoke end at the felloes travels faster than the spoke end at the hub.

In the ideal machine power in equals power out.  And power equals the torque (twisting force) multiplied by the angular velocity (how fast something spins around).  The key to the wheel and axle is the different angular velocities of the outer surfaces of the axle and wheel.  If power remains the same while the angular velocity changes then the torque must change.  Let’s use some meaningless numbers to illustrate this point.  The angular velocity is 4 and the torque is 2 on a wheel’s surface and the angular velocity is 2 and the torque is 4 on an axle.  Power in equals 8 while power out also equals 8.  But the torque increases.  So using the wheel and axle gives us mechanical advantage.  The ability to amplify force to do useful work for us.

Mechanical Advantage amplifies our Input Force to do Useful Work for Us

What makes a screwdriver work is the handle on it that we grip.  Which represents the outer surface of the wheel.  While the metal shaft the handle fastens to is the axle.  The handle provides a larger surface for our hand to grip.  Allowing us to apply a greater turning force (torque) to the handle than we could to the metal shaft.  The angular velocity of the surface of the handle is greater than the metal shaft.  So the torque of the metal shaft is greater than the torque we apply to the handle of the screwdriver.

The mechanical advantage amplifies our input force to do useful work for us.  To turn a screw that our fingers aren’t strong enough to turn.  Just as the handle on the water spigot allows us to twist it open.  And the door knob allows us to twist open the latching mechanism to open a door.  Things we couldn’t do without a large handle to grasp and twist.  To amplify our limited force.  To do useful work.

The old-fashioned water well is another example.  Across the top of the well is an axle.  A length of rope long enough to reach the water below is attached to a bucket.  The other end is attached to the axle.  Also attached to the axle is a wheel that we can turn by hand.  Or a hand crank.  As we turn the wheel or crank the rope wraps around the axle.  Pulling up the bucket full of water.  The speed of our hand spinning the wheel or the crank is greater than the speed of the spinning axle.  That is, our input angular velocity is reduced.  Which increases the torque on the axle.  Allowing it to pull up a heavy bucket of water that we couldn’t do as easily without the wheel and axle.

Using more Gears in a Gear Train can greatly Reduce the Angular Velocity which Greatly Increases the Output Force

We can amplify our input force more by adding some additional wheels.  And some gears.  For example, when we started harvesting sugarcane we used a mechanical press to squeeze the juice out of the cane.  And we did this by running the sugarcane through a couple of rollers with a narrow gap between them.  Crushing and pulling this cane through these rollers, though, required a lot of force.  Which we produced with a couple of wheels and axles.  One axle was the roller.  Attached to this axle was a large wheel.  Only we didn’t turn this wheel.  This wheel was a large gear.  Its teeth meshed with the teeth of a smaller gear on another axle.  Attached to this second axle was another wheel.  With a hand crank attached to it.

When we turned this wheel we rotated the small gear on the hand-crank axle.  This gear turned the larger gear attached to the roller axle.   Which pulled and crushed the cane through the press.  This reduced the angular velocity twice.  Thus increasing the torque twice.  Which twice amplified our input force.  Using more gears in a gear train can greatly reduce the angular velocity from the input axle to the output axle.  Greatly increasing the output force.  Like in a motor vehicle.  The engine spins at a high angular velocity.  The power output of the engine spins a gear train inside a transmission.  Greatly reducing the output angular velocity.  While greatly increasing the turning force sent to the drive wheels.

High-spinning electric motors have replaced the hand-crank on modern sugarcane presses.  These use a gear train or a belt and pulley system (or both) to reduce the spinning speed of the electric motor.  So when the force turns the rollers it doesn’t pull the cane through dangerously fast.  It pulls it through slow but with great force.  Which will flatten the cane and squeeze every last drop of fluid from it.  Or someone’s hand if it gets caught in the rollers.  Which usually have hand-guards around them to prevent that from happening.  But some people still operate machines that have no such guards as they hand-feed the cane into the press.  This is a disadvantage of using mechanical advantage.  For it can cause great harm just as easily as it can do useful work for us.


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