Big and Heavy things that Travel Fast along the Ground have a lot of Dangerous Kinetic Energy

Posted by PITHOCRATES - December 1st, 2013

Week in Review

The most dangerous parts of flight are the landing and taking off parts.  Why?  Because planes are big and heavy.  And they travel fast.  And whenever anything big and heavy travels fast near the ground bad things can happen.  Because that’s a lot of kinetic energy that can do a lot of damage when it comes to a sudden and unexpected stop.  But up in the air away from the ground planes easily earn their title as the safest way to travel.  For up in the lonely expanses of the sky they can travel in excess of 500 miles per hour without a care in the world.  Because the odds of them striking anything are virtually zero.  This is where big and heavy things that travel fast belong.  Not on the ground.  Like high-speed rail.  For even low-speed rail can be dangerous (see New York train derailment: Safety officials recover ‘black box’ by Tina Susman posted 12/1/2013 on the Los Angeles Times).

Investigators have recovered the “event recorder” from a Metro-North train that derailed in New York City early Sunday, a major step toward determining what caused the crash that killed four people and left scores injured…

Earl F. Weener of the National Transportation Safety Board said at a news briefing that the agency expected to have investigators on the scene in the Spuyten Duyvil area of the Bronx for a week to 10 days.

“Our mission is to understand not just what happened but why it happened, with the intent of preventing it from happening again,” Weener said. He said investigators had not yet talked to the train’s operator. Some local media have said the operator has claimed that he tried to slow down at the sharp curve where the derailment occurred but that the brakes failed.

The speed limit at the curve is 30 mph, compared to about 70 mph on straight sections of track.

Gov. Andrew Cuomo said the area is “dangerous by design,” because of the curve, but he said the bend in the track alone could not be blamed for the crash.

“That curve has been here for many, many years,” he told reporters at the scene, as darkness fell over the wreckage. “Trains take the curve every day … so it’s not the fact that there’s a curve here. We’ve always had this configuring. We didn’t have accidents. So there has to be another factor.”

High-speed rail is costly.  Because it needs dedicated track.  Overhead electric wires.  No grade crossings.  Fencing around the track.  Or installed on an elevated viaduct.  To prevent any cars, people or animals from wandering onto the track.  They need banked track for high-speed curves.  And, of course, they can’t have any sharp curves.  Because curves cause a train to slow down.  If they don’t they can derail.  Which may be the reason why this commuter train derailed.  It may have entered a curved section of track at a speed too great for its design.  Which shows the danger of fast trains on sharp turns.

There haven’t been many high-speed rail accidents.  But there have been a few.  All resulting in loss of life.  Because big and heavy things that travel fast along the ground have a lot of kinetic energy.  And if something goes wrong at these high speeds (collision with another train or derailment) by the time that kinetic energy dissipates it will cause a lot of damage to the train, to its surroundings and to the people inside.

The high speed of today’s high-speed trains is about 200 mph.  Not even half of what modern jetliners can travel at.  Yet they cost far more.  Most if not all passenger rail needs government subsidies.  Air travel doesn’t.  Making high-speed rail a very poor economic model.  But they are capital and labor intensive.  Which is why governments build them.  So they can spend lots of money.  And create a lot of union jobs.  Which tends to help them win elections.

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Trucks, Trains, Ships and Planes

Posted by PITHOCRATES - August 21st, 2013

Technology 101

Big Over-the-Road Tractor Trailer Trucks have Big Wheels so they can have Big Brakes

If you buy a big boat chances are you have a truck or a big SUV to pull it.  For rarely do you see a small car pulling a large boat.  Have you ever wondered why?  A small car can easily pull a large boat on a level (or a near level) surface.  That’s not the problem.  The problem is stopping once it gets moving.  For that is a lot of mass.  Creating a lot of kinetic energy (one half of the mass times velocity squared).  Which is dissipated as heat as brake shoes or pads rub against the wheels.  This is why you need a big truck or SUV to pull a boat.  So you can stop it once it gets moving.

Big trucks and big SUVs have big wheels and big brakes.  Large areas where brake pads/shoes press against a rotating wheel.  All of which is heavy duty equipment.  That can grab onto to those wheels and slow them down.  Converting that kinetic energy into heat.  This is why the big over-the-road tractor trailer trucks have big wheels.  So they can have big enough brakes to stop that huge mass once it gets moving.  Without the brakes turning white hot and melting.  Properly equipped trucks can carry great loads.  Moving freight safely across our highways and byways.  But there is a limit to what they can carry.  Too much weight spread between too few axles will pound the road apart.  Which is why the state police weighs our trucks.  To make sure they have enough axles supporting the load they’re carrying.  So they don’t break up our roads.  And that they can safely stop.

It’s a little different with trains.  All train cars have a fixed number of axles.  But you will notice the size of the cars differ.  Big oversized boxcars carry a lot of freight.  But it’s more big than heavy.  Heavy freight, on the other hand, like coal, you will see in smaller cars.  So the weight they carry doesn’t exceed the permissible weight/axle.  If you ever sat at a railroad crossing as a train passed you’ve probably noticed that the rail moves as the train travels across.  Watch a section of rail the next time you’re stopped by a train.  And you will see the rail sink a little beneath the axle as it passes over.

If a Ship is Watertight and Properly Balanced it can be covered in Green Water and Rise back to the Surface

So the various sizes of train cars (i.e., rolling stock) keeps each car from being overloaded.  Unlike a truck.  Steel haulers and gravel trains (i.e., dump trucks) have numerous axles beneath the load they’re carrying.  But these axles are retractable.  For the more wheels in contact with the road the more fuel is needed to overcome the friction between the tires and the road.  And the more tires in contact with the road the more tire wear there is.  Tires and fuel are expensive.  So truckers like to have as few tires in contact with the road as possible.  When they’re running empty they will have as many of these wheels retracted up as possible.  Something you can’t do with a train.

That said, a train’s weight is critical for the safe operation of a train.  In particular, stopping a train.  The longer a train is the more distance it takes to stop.  It is hard to overload a particular car in the string of cars (i.e., consist) but the total weight tells engineers how fast they can go.  How much they must slow down for curves.  How much distance they need to bring a train to a stop.  And how many handbrakes to set to keep the train from rolling away after the pressure bleeds out of the train line (i.e., the air brakes).  You do this right and it’s safe sailing over the rails.  Ships, on the other hand, have other concerns when it comes to weight.

Ships float.  Because of buoyancy.  The weight of the load presses down on the water while the surface of the water presses back against the ship.  But where you place that weight in a ship makes a big difference.  For a ship needs to maintain a certain amount of freeboard.  The distance between the surface of the water and the deck.  Waves toss ships up and down.  At best you just want water spray splashing onto your deck.  At worst you get solid water (i.e., green water).  If a ship is watertight and properly balanced it can be covered in green water and rise back to the surface.  But if a ship is loaded improperly and lists to one side or is low in the bow it reduces freeboard.  Increases green water.  And makes it less likely to be able to safely weather bad seas.  The SS Edmund Fitzgerald sank in 1975 while crossing Lake Superior in one of the worst storms ever.  She was taking on water.  Increasing her weight and lowering her into the water.  Losing freeboard.  Had increasing amounts of green water across her deck.  To the point that a couple of monster waves crashed over her and submerged her and she never returned to the surface.  It happened so fast that the crew was unable to give out a distress signal.  And as she disappeared below the surface her engine was still turning the propeller.  Driving her into the bottom of the lake.  Breaking the ship in two.  And the torque of the spinning propeller twisting the stern upside down.

Airplanes are the only Mode of Transportation that has two Systems to Carry their Load

One of the worst maritime disasters on the Great Lakes was the sinking of the SS Eastland.  Resulting in the largest loss of life in a shipwreck on the Great Lakes.  In total 844 passengers and crew died.  Was this in a storm like the SS Edmund Fitzgerald?  No.  The SS Eastland was tied to the dock on the Chicago River.  The passengers all went over to one side of the ship.  And the mass of people on one side of the ship caused the ship to capsize.  While tied to the dock.  On the Chicago River.  Because of this shift in weight.  Which can have catastrophic results.  As it can on airplanes.  There’s a sad YouTube video of a cargo 747 taking off.  You then see the nose go up and the plane fall out of the sky.  Probably because the weight slid backwards in the plane.  Shifting the center of gravity.  Causing the nose of the plane to pitch up.  Which disrupted the airflow over the wings.  Causing them to stall.  And with no lift the plane just fell out of the sky.

Airplanes are unique in one way.  They are the only mode of transportation that has two systems to carry their weight.  On the ground the landing gear carries the load.  In the air the wings carry the load.  Which makes taking off and landing the most dangerous parts of flying.  Because a plane has to accelerate rapidly down the runway so the wings begin producing lift.  Once they do the weight of the aircraft begins to transfer from the landing gear to the wings.  Allowing greater speeds.  However, if something goes wrong that interferes with the wings producing lift the wings will be unable to carry the weight of the plane.  And it will fall out of the sky.  Back onto the landing gear.  But once the plane leaves the runway there is nothing the landing gear can gently settle on.  And with no altitude to turn or to glide back to a runway the plane will fall out of the sky wherever it is.  Often with catastrophic results.

A plane has a lot of mass.  And a lot of velocity.  Giving it great kinetic energy.  It takes long runways to travel fast enough to transfer the weight of the aircraft from the landing gear to the wings.  And it takes a long, shallow approach to land an airplane.  So the wheels touch down gently while slowly picking up the weight of the aircraft as the wings lose lift.  And it takes a long runway to slow the plane down to a stop.  Using reverse thrusters to convert that kinetic energy into heat.  Sometimes even running out of runway before bringing the plane to a stop.  No other mode of transportation has this additional complication of travelling.  Transferring the weight from one system to another.  The most dangerous part of flying.  Yet despite this very dangerous transformation flying is the safest mode of traveling.  Because the majority of flying is up in the air in miles of emptiness.  Where if something happens a skilled pilot has time to regain control of the aircraft.  And bring it down safely.

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High-Speed Train crashes in Spain because things moving at High Speeds on the Ground can be Very Dangerous

Posted by PITHOCRATES - July 27th, 2013

Week in Review

Trains are heavy.  Getting a train moving is one thing.  But getting it to stop is another.  Because heavy things moving fast have a lot of kinetic energy.  The energy of something in motion.  In classical mechanics we calculate the kinetic energy by multiplying one half of the mass times the velocity squared.  That last part is really important.  The velocity part.  For as the speed increases the kinetic energy increases by a far greater amount.  For example, a train increasing speed from 30 kilometers per hour (18 mph) to 190 kilometers per hour (114 mph) increases its speed by 533%.  But because we square the velocity the kinetic energy increases by 3,911%.   Making high-speed rail more dangerous than regular rail.  Because of the great amounts of kinetic energy involved.

Airplanes are very heavy.  They travel at great speeds.  And have great amounts of kinetic energy.  Which is why plane crashes or so horrific.  Anything with that amount of kinetic energy suddenly stopping dissipates that energy in great heat, noise and the explosion of solid parts.  But plane crashes, thankfully, are rare.  For when they are travelling at those great speeds they’re up in the air thousands of feet (or more) away from anything they can hit.  And if there is a malfunction they can fall safely though the sky (with enough altitude) until the pilots can recover the aircraft.  For airplanes have the best friend to high speed objects.  A lot of empty space all around them.  Not so with high-speed rail (see Driver in custody after 80 killed in Spain train crash by Teresa Medrano and Tracy Rucinski posted 7/25/2013 on Reuters).

The driver of a Spanish train that derailed, killing at least 80 people, was under police guard in hospital on Thursday after the dramatic accident which an official source said was caused by excessive speed.

The eight-carriage train came off the tracks, hit a wall and caught fire just outside the pilgrimage destination Santiago de Compostela in northwestern Spain on Wednesday night. It was one of Europe’s worst rail disasters…

Video footage from a security camera showed the train, with 247 people on board, hurtling into a concrete wall at the side of the track as carriages jack-knifed and the engine overturned…

El Pais newspaper said the driver told the railway station by radio after being trapped in his cabin that the train entered the bend at 190 kilometers per hour (120 mph). An official source said the speed limit on that stretch of twin track, laid in 2011, was 80 kph…

Investigators were trying to find out why the train was going so fast and why security devices to keep speed within permitted limits had not slowed the train…

Spain’s rail safety record is better than the European average, ranking 18th out of 27 countries in terms of railway deaths per kilometers traveled, the European Railway Agency said. There were 218 train accidents in Spain between 2008-2011, well below the EU average of 426 for the same period.

There are no rails to derail from in the air.  And no concrete walls to crash into.  Air travel requires no infrastructure between terminal points.  High-speed rail travel requires a very expensive, a very precise and a highly maintained infrastructure between terminal points.  As well as precise controls to keep the train from exceeding safe speeds.  Planes do, too.  But when you have thousands of feet of nothingness all around you there is time to make adjustments before something catastrophic happens.  Like derailing when speeding through a curve too fast.

Air travel is safer than high-speed rail travel.  Which is why when a plane crashes it’s big news.  Because it happens so rarely these days.  Thanks to good aircraft designs.  Good pilots.  And having thousands of feet of nothingness all around you when flying at speeds close to 950 kph (570 mph).  Unlike having a concrete wall just a few feet away from a train traveling at high speeds.

High-speed rail may work in France and Japan.  The only two rail lines to pay for themselves are in these countries.  But every other passenger rail line in the world needs a government subsidy.  Because the costs of a rail infrastructure are just so great.  Making high-speed rail more of a source of union jobs than an efficient means of transportation.  Which is why they are a fixture in countries with liberal governments.  Who subsidize the high cost of these union jobs with taxpayer money.  In exchange for votes in the next election.

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Waterwheel, Rotational Motion, Reciprocal Motion, Steam Engine, Internal Combustion Engine and Hydraulic Brakes

Posted by PITHOCRATES - December 5th, 2012

Technology 101

To Keep People on Trains they Undercharge Passengers and make up the Difference with Government Subsidies

We built some of our first factories on or near a river.  Where we could use that river’s current to turn a waterwheel.  To provide a rotational motion that could do work for us.  We transmitted that rotational motion via a main drive shaft through a factory where it could drive machinery via belts and pulleys.  Once we developed the steam engine to provide that rotational motion we could move our factories anywhere.  Not just on or near a river.  Giving us greater freedom.  And permitting greater economic growth.  As we put those steam engines onto rails.  That transported freight and people all across the country.

Trains are nice.  But expensive.  To go anywhere on a train you need train tracks going there.  But train tracks are incredibly expensive to lay.  And maintain.  If you ever stared at a set of train tracks you probably noticed something.  There aren’t a lot of trains going by on them.  When a train stops you when you’re running late or bringing home dinner it may feel like trains are always stopping you.  But if you parked at those same tracks for a few hours you wouldn’t see a lot of trains.  Because even the most polished rails (the more train traffic the more polished the rails) are unused more than they are used.

This is why trains are very expensive.  Tracks cost a lot of money to lay and maintain.  Costs that a railroad has to recoup from trains using those rails.  And when you don’t have a lot of trains on those rails you have to charge a lot for the trains that do travel on them.  A mile-long train pulling heavy freight can pay a lot of revenue.  And make a railroad profitable.  But passenger trains are not a mile long.  And carry few people.  Which means to make money on a passenger train you’d have to charge more for a ticket than people would pay.  To keep people on trains, then, they have to undercharge passengers.  And make up the difference with government subsidies.

A Crank Shaft and Combustion Timing takes Reciprocal Motion of Pistons and Converts it into Rotational Motion

This is why people drive places instead of taking the train.  It’s far less expensive to take the car.  And there are roads everywhere.  Built and maintained by gas taxes, licenses and fees.  And if you’ve ever driven on a road you probably noticed that there are a lot of cars, motorcycles, trucks and buses around you.  With so many vehicles on the roads they each can pay a small amount to build and maintain them.  Which is something the railroads can’t do.  Only trains can travel on train tracks.  But cars, motorcycles, trucks and buses can all travel on roads.  This is why driving a car is such a bargain.  Economies of scale.

To operate a train requires a massive infrastructure.  Dispatchers control the movement of every train.  Tracks are broken down into blocks.  The dispatchers allow only one train in a block at a time.  They do this for a couple of reasons.  Trains don’t have steering wheels.  And can take up to a mile to stop.  So to operate trains safely requires keeping them as far apart from each other as possible.  Traveling on roads is a different story.  There are no dispatchers separating traffic.  Cars, motorcycles, trucks and buses travel very close together.  Starting and stopping often.  Traveling up to high speeds between traffic lights.  With motorcycles and cars weaving in and out among trucks and buses.  Avoiding traffic and accidents by speeding up and slowing down.  And steering.

Driving a car today is something just about anyone 16 and older can do.  Thanks to the remarkable technology that makes a car.  Starting with the internal combustion engine.  The source of power that makes everything possible.  Just like those early waterwheels the source of that power is rotational motion.  But instead of a river providing the energy an internal combustion engine combusts gasoline to push pistons.  A crank shaft and combustion timing takes that reciprocal motion of the pistons and converts it into rotational motion.  Spinning a drive shaft that provides power to drive the car.  As well as power all of its accessories.

The Friction of Brake Shoe or Pad on Steel slows the Car converting Kinetic Energy into Heat

The first cars required a lot of man-power.  It took great strength to rotate the hand-crank to start the engine.  Sometimes the engine would spit and cough.  And kick back.  Breaking the occasional wrist.  Once started it took some leg-power to depress the clutch to shift gears.  It took a little upper body strength to turn the steering wheel.  And some additional leg-power to apply the brakes to stop the car.  In time we replaced the hand-crank with the electric starter.  We replaced the clutch and gearbox with the automatic transmission.  We added power steering and power breaks to further reduce the amount of man-power needed to drive a car.  Today a young lady in high heels and a miniskirt can drive a car as easily and as expertly as the first pioneers who risked bodily harm to drive our first cars.

The internal combustion engine can spin a crankshaft very fast and accelerate a car to great speeds.  Which is good for darting in and out of traffic.  But traffic occasional has to stop.  Which is easier said than done.  For a heavy car moving at speed has a lot of kinetic energy.  You can’t destroy energy.  You can only convert it.  And in the case of slowing down a car you have to convert that kinetic energy into heat.  When you press the brake pedal you force hydraulic fluid from a master cylinder to small cylinders at each wheel.  As fluids cannot compress when you apply a force to the fluid that force is transmitted to something than can move.  In the case of stopping a car it is either a brake shoe that presses against the inside of the car’s wheels.  Or a caliper that clamps down on a disc.  The friction of brake shoe or pad on steel slows the car.  Converting that kinetic energy into heat.  In some cases of excessive braking (on a train or a plane) the heat can be so excessive that the wheels or discs glow red.

So as the internal combustion engine and the brakes play their little games of speeding up and slowing down a car the rotational power of the crankshaft drives other accessories.  Such as power steering.  Where a belt and pulley transfers that rotational power to a power steering pump.  The pump pushes fluid to the steering gear to assist in turns.  Another belt and pulley connects an alternator to the crankshaft to produce electricity to provide power for the car’s electrical systems.  And to charge the battery so it can spin the automatic starter.  Another belt and pulley connects another compressor to the crankshaft.  This one for air conditioning.  That allows us to alight from our cars shower-fresh on the hottest and most humid days of the year.  And, finally, antifreeze removes the heat of combustion from the internal combustion engine and transfers it to a heating core inside the passenger compartment.  Allowing a warm and comfortable drive home during the coldest of days.  As well as keeping our windows free of snow and ice so we can see to drive safely on our way home.  Through bumper to bumper traffic.  Something we do day after day with the ease of doing the laundry.  Thanks to the remarkable technology that we take for granted that makes a car.

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Conservation of Energy, Potential Energy, Kinetic Energy, Waterwheels, Water Turbine, Niagara Falls, Dams, and Hydroelectric Power

Posted by PITHOCRATES - July 25th, 2012

Technology 101

Roller Coasters use Gravity to Convert Energy back and forth between Potential Energy and Kinetic Energy

We cannot destroy energy.  All we can do is convert it.  It’s a law of physics.  The law of conservation of energy.  A roller coaster shows this.  Where roller coasters move by converting potential energy into kinetic energy.  And then by converting kinetic energy back into potential energy.

The best roller coasters race down tall inclines gaining incredible speed.  The taller the coaster the faster the speed.  That’s because of potential energy (stated in units of joules).  Which is equal to the mass times the force of gravity times the height.  The last component is what makes tall roller coasters fast.  Height.  As the cars inch over the summit gravity begins pulling them down.  And the longer gravity can pull them down the more speed they can gain.  At the bottom of the hill the height is zero so the potential energy is zero.  All energy having been converted into kinetic energy (also stated in units of joules).

Roller coasters travel the fastest at the lowest points in the track.  Where potential energy equals zero.  While kinetic energy is at its highest.  Which is equal to one half times the mass times the velocity squared.  So the higher the track the more time gravity has to accelerate these cars.  At their fastest speed they start up the next incline.  Where the force of gravity begins to pull on them.  Slowing them down as they climb up the next hill.  Converting that kinetic energy back into potential energy.  When they crest the hill for a moment their speed is zero so their kinetic energy is zero.  All energy having been converted back into potential energy.  Where gravity tugs those cars down the next incline.  And so on up and down each successive hill.  Where at all times the sum of potential energy and kinetic energy equals the same amount of joules.  Maximum potential energy is at the top.  Maximum kinetic energy is at the bottom.  And somewhere in the middle they each equal half of their maximum amounts.

(This is a simplified explanation.  Additional forces are ignored for simplicity to illustrate the relation between potential energy and kinetic energy.)

We build Dams on Rivers  to do what Niagara Falls does Naturally

So once over the first hill roller coasters run only on gravity.  And the conversion of energy from potential to kinetic energy and back again.  Except for that first incline.  Where man-made power pulls the cars up.  Electric power.  Produced by generators.  Spun by kinetic energy.  Produced from the expanding gases of combustion in a natural gas-powered plant.  Or from high-pressure steam produced in a coal-fired power plant or nuclear power plant.  Or in another type of power plant that converts potential energy into kinetic energy.  In a hydroelectric dam.

Using water power dates back to our first civilizations.  Then we just used the kinetic energy of a moving stream to turn a waterwheel.  These waterwheels turned shafts and pulleys to transfer this power to work stations.  So they couldn’t spin too fast.  Which wasn’t a problem because people only used rivers and streams with moderate currents.  So these wheels didn’t spin fast.  But they could turn a mill stone.  Or run a sawmill.  With far more efficiency than people working with hand tools.  But there isn’t enough energy in a slow moving river or stream to produce electricity.  Which is why we built some of our first hydroelectric power plants at Niagara Falls.  Where there was a lot of water at a high elevation that fell to a lower elevation.  And if you stick a water turbine in the path of that water you can generate electricity.

Of course, there aren’t Niagara Falls all around the country.  Where nature made water fall from a high elevation to a low elevation.  So we had to step in to shape nature to do what Niagara Falls does naturally.  By building dams on rivers.  As we blocked the flow of water the water backed up behind the dam.  And the water level climbed up the river banks to from a large reservoir.  Or lake.  Raising the water level on one side of the dam much higher than the other side.  Creating a huge pool of potential energy (mass times gravity times height).  Just waiting to be converted into kinetic energy.  To drive a water turbine.  The higher the height of the water behind the dam (or the higher the head) the greater the potential energy.  And the greater the kinetic energy of the water flow.  When it flows.

Hydroelectric Power is the Cleanest and Most Reliable Source of Renewable Energy-Generated Power

Near the water level behind the dam are water inlets into channels through the dam or external penstocks (large pipes) that channels the water from the high elevation to the low elevation and into the vanes of the water turbine.  The water flows into these curved vanes which redirects this water flow down through the turbine.  Creating rotational motion that drives a generator.  After exiting the turbine the water discharges back into the river below the dam.

Our electricity is an alternating current at 60 hertz (or cycles per second).  These turbines, though, don’t spin at 60 revolutions per second.  So to create 60 hertz they have to use different generators than they use with steam turbines.  Steam turbines spin a generator with only one rotating magnetic field to induce a current in the stator (i.e., stationary) windings of the generator.  They can produce an alternating current at 60 hertz because the high pressure steam can spin these generators at 60 revolutions per second.  The water flowing through a turbine can’t.  So they add additional rotational magnetic fields in the generator.  Twelve rotational magnetic fields can produce 60 hertz of alternating current while the generator only spins at 5 revolutions per second.  Adjustable gates open and close to let more or less water to flow through the turbine to maintain a constant rotation.

The hydroelectric power plant is one of the simplest of power generating plants.  There is no fuel needed to generate heat to make steam.  No steam pressure to monitor closely to prevent explosions.  No fires to worry about in the mountains of coal stored at a plant.  No nuclear meltdown to worry about.  And no emissions.  All you need is water.  From snow in the winter that melts in the spring.  And rain.  Not to mention a good river to dam.  If the water comes the necessary head behind the dam will be there to spin those turbines.  But sometimes the water isn’t there.  And the dams have to shut down generators because there isn’t enough water.  But hydroelectric power is still the cleanest and most reliable source of electric power generated from renewable energy we have.  But it does have one serious drawback.  You need a river to dam.  And the best spots already have a dam on them.  Leaving little room for expansion of hydroelectric power.  Which is why we generate about half of our electric power from coal.  Because we can build a coal-fired power plant pretty much anywhere we want to.  And they will run whether or not we have snow or rain.  Because they are that reliable.

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Energy Absorption and Conversion, Vibration Isolation, Dampening, Oscillation, Advanced Building Technologies, Building Codes and Code Enforcement

Posted by PITHOCRATES - March 7th, 2012

Technology 101

Springs and Shock Absorbers on a Car provides Vibration Isolation from the Shocks of the Road

Roads aren’t perfect.  They have their bumps.  And their potholes.  Especially in the north.  Where they use salt to melt snow and ice.  Which get to the reinforcing steel within the concrete.  Causing it to corrode.  Further stressing and cracking the concrete.  Allowing water to get underneath the concrete.  Where it expands as it freezes, heaving and cracking the road.  Then there’s the normal heating and cooling.  That can buckle and crack blacktop.  Heavy truck traffic that stresses and hammers our roads.  Even sinking slightly into our asphalt roads making tire ruts.  And then there are railroad crossings.  Sewers and manholes that aren’t flush with the surface.  There’s a lot out there to make for a rough ride.  Yet in a new car you barely feel any of this.  And you can drink a cup of coffee while driving without it splashing out of the cup.  Why?

Because the shocks from the rode are isolated from the passenger compartment.  Air-inflated rubber tires smooth out much of that rough ride.  By compressing to absorb some bumps.  Then expanding back to their original shape.  Springs handle the larger bumps.  Which compress underneath the car as the tires hit a large bump.  Absorbing the energy from that impact before it reaches the passenger compartment.  By using it to compress a spring.  Then the energy in that compressed spring releases and the spring expands until it can expand no longer.  Placing the stretched spring into tension.  The stored energy in the tensioned spring compresses it again.  And this continues back and forth until the energy fully dissipates.  Or is absorbed in a shock absorber.  That dampens the oscillation of the spring.  Bringing it back to a steady-state quickly.  Further smoothing out the ride.

A car is a magnificent piece of engineering.  From converting a fuel into motive power.  To brakes slowing a car down by converting kinetic energy into heat via the friction of brake pads or shoes on rotors or drums.  To the isolation and dampening of the road forces imparted to the car.  It’s a remarkable control and conversion of energy.  That provides for a comfortable ride.  And a smooth ride.  Smooth enough to enjoy a cup of coffee while driving.  Without being too distracted from the business of driving.

Tuned Mass Dampers prevent Dangerous Oscillations in Buildings that can lead to Structural Failures

But a car moving over a road is not the only way energy transfers between the earth and something manmade.  Sometimes the earth moves.  And energy is transferred into something stationary.  Manmade structures like buildings and bridges.  During earthquakes.  And some of these stationary things get damaged.  Some even collapse.  Depending on how we constructed them.  And how similar they are to a car.

Tectonic plates are trying to move.  But the friction between these plates as they jam into each other holds them in place.  Until the pressure builds so much that the plates shift.  Causing an earthquake.  Sending seismic waves through the earth.  In active seismic regions structures need to be like cars.  They need isolation and dampening from the shockwaves caused by shifting tectonic plates.  For during a seismic event these shockwaves ‘grab’ these structures by their foundations and shake them.  This energy applying great forces on these buildings.  Energy that needs to go somewhere.  Because of the conservation of energy principle.  We can’t create it.  Nor we can destroy it.  At best we can redirect it.  Absorb it.  Or convert it.  Like converting the forward movement of a car (kinetic energy) into heat (created during braking).  Or the conversion of kinetic and potential energy of moving springs into heat (via shock absorbers). 

Waves have an amplitude and a frequency.  They oscillate.  That is, they vibrate.  And have energy.  Which is why we build buildings and bridges to move.  To bend and sway.  To dissipate this energy.  For if they were too rigid the forces could instead lead to a structural failure.  However, if they move too much and the external force is in ‘resonance’ with the building’s natural frequency of movement, this oscillation can grow.  Producing great vibrations.  (Like a car driving without any shock absorbers.)  And great forces on the structural integrity of the building.  Itself leading to a structural failure.  That’s why high rises include dampening systems.  Such as tuned mass dampers.  A great mass suspended within a building and restrained by hydraulic cylinders.  Such as the tuned mass damper atop Taipei 101 in Taiwan.  So when the building sways in one direction the mass swings in the opposite direction.  Thus dampening the oscillation of the building.

Free Market Capitalism allows a Higher Standard of Living and Creates the Kind of Wealth that can build Safe Houses and Buildings

Smaller buildings may use springs-with-damper base isolators.  Which does the same thing springs and shocks do for a car.  Isolates the structure from vibrations.  But using the proper building materials to allow a building to move or withstand destructive forces without structural failure provides most seismic protection.  And this is nothing new.  The Machu Picchu Temple of the Sun in Peru is an early example of good seismic engineering.  Peru sits on the Ring of Fire.  A highly seismic region that circles the Pacific Ocean.  The Inca were highly skilled stone cutters.  They built the Machu Picchu Temple of the Sun without mortar.  Because of this the stone can move during seismic events.  Which has let it stand through the millennia.  Today we use mortar.  And reinforcing steel to strengthen our masonry construction (these blocks can’t move but when the walls they make crack the steel inside keeps them from collapsing).  As well as other advanced building technologies.  And ever evolving building codes and code enforcement to make sure builders meet the exacting standards of these technologies.  To keep these buildings from collapsing and killing hundreds of thousands of people.  Which is why in the most modern and advanced cities in seismic regions survive some of the worst seismic events with minimal loss of life.  Where they count deaths in the hundreds instead of the hundreds of thousands.  As they did before we used these advanced building technologies.

The countries and regions sitting on the Ring of Fire (New Zealand, Indonesia, the Philippines, Japan, Alaska, California, Mexico, Peru and Chile) use some of the most advanced building technologies.  And can withstand some of the most severe earthquakes.  With little loss of life.  Now compare that to the impoverished country of Haiti.  Their 2010 earthquake was devastating, claiming 230,000 lives.  Because they have no such building codes or code enforcement.  Or advanced building technology.  Because Haiti is not a nation of free market capitalism.  Or the rule of law.  But one of political corruption.  And abject poverty.  Are they predisposed to be impoverished?  No.  Because countries can change.  If they embrace free market capitalism.  And the rule of law.

Chile was one such country at one time.  Corrupt.  And anti-capitalistic.  During the heyday of Keynesian economics.  Where nations said goodbye to the gold standard.  And ramped up their printing presses.  Igniting hyperinflation.  Including the Chileans.  But they changed.  Thanks to the Chicago Boys.  Chilean economists schooled in the Chicago school of economics.  With a little help from Milton Friedman.  Perhaps the most esteemed member of the Chicago school. Economic reforms produced solid economic growth.  A prosperous middle class.  And advanced building technologies, building codes and code enforcement.  So when Chile suffered a more powerful earthquake than Haiti did that same year Chile measured their death toll in the hundreds.  Not the hundreds of thousands as they did in Haiti.  And the major difference between these two nations?  Chile has a higher standard of living than Haiti.  And has less poverty.  Because Chile embraces free market capitalism.  Which creates the kind of wealth that can build safe houses.  And safe buildings.  For everyone.  Not just the ruling elite.

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There Were Planes and There Were People

Posted by PITHOCRATES - September 12th, 2010

Yesterday was the anniversary of 9/11.  Today is the anniversary of the start of the conspiracy theories.

There were those who were adamant that it was an inside job.  That George W. Bush did it.  They said he was the brilliant mastermind behind the attacks.  When they weren’t calling him the incompetent in chief.  They pointed to the Pentagon attack.  An obvious missile attack.  There was no way a big plane like Boeing 757 could thread its way down to a streetlight-top altitude and hit the side of that building.  Maybe a cruise missile could, but not a commercial jet.  All right.  Let’s accept that theory.  Now answer me this.  Where is the plane?  Where are the passengers and crew?  Where are they today?

THE MIGHTY ARMS OF ATLAS

The engineers designed the Twin Towers to withstand the impact of an airplane.  To make it safe like the Empire State Building.  For when a plane struck the Empire State Building, it didn’t collapse.  But the Twin Towers did.  Proof that the Bush administration purposely blew up the Twin Towers.  And those commercial jetliners that hit the towers that day?  That was just a coincidence.  Or a clever ruse.  Perhaps military drones sent in to allay suspicion.  Or that Bush used unwitting terrorists as convenient patsies for his devilish schemes.  Just something that an evil genius would do.

The plane that crashed into the Empire State Building was a World War II medium bomber (B-25) with a cruising speed of about 230 mph.  The B-25 had a maximum speed of about 275 mph and had a range of about 1,300 miles.  It weighed just under 20,000 pounds empty.  It carried approximately 670 gallons of fuel when fully fueled.   The Boeing 767, on the other hand, has the following stats:  typical cruising speed: 530 mph; maximum takeoff weight: 450,000 pounds; maximum range: 5,625 nautical miles; maximum fuel capacity: 23,980 gallons.

The B-25 was a gorgeous, fast and lethal plane.  For its time.  But it pales in comparison to the 767.  The weight and speed of a 767 hitting a building could not be anything but cataclysmic.  But the Twin Towers withstood those impacts.  They absorbed tremendous amounts of kinetic energy.  Far more than the designers ever envisioned.  And yet the mighty arms of Atlas still reached skyward.  But that kinetic energy did its damage.  It compromised the fire proofing on the structural steel.  And there was all that fuel.  And fire.  A scenario no designer ever contemplated.

The Twin Towers had an ingenious open-floor plan.  Instead of having big columns in the office spaces, the sides of the building carried the load.  The floors were ‘hung’ from this structural steel.  The floors provided the rigidity of the towers while the exterior walls carried the weight.  With the fireproofing compromised, though, the steel spanning the floors heated up in that inferno.  It began to soften.  And sag.  This compromised the structural integrity.  The steel members could move.  Attachment points strained.  And failed.  A floor collapsed.  This increased instability.  More movement.  More stress.  More failures.  More floors collapsed.  One on top of another.  And then walls came tumbling down.

It was all that jet fuel.  It could sustain a fire to burn long enough and hot enough to soften structural steel (which is why structural steel is fireproofed).  That’s what brought the Twin Towers down.  Not George W. Bush.

THEY FOUGHT BACK

Of course, there’s not much the conspirators can say about the 4th plane.  Because of cell phones.  After the hijacking, passengers talked to family/others.  They learned that hijacked commercial jetliners attacked the Twin Towers and the Pentagon.  The passengers and crew on this hijacked jetliner knew what was going to happen.  They were going to die.  So they became the first to go on the offensive in the War on Terror.  They won the first skirmish in this new war.  A battle they entered likely knowing they would not survive.  But they swallowed their fear.  And acted.  Ordinary people doing extraordinary things.  God rest their souls.

There are a lot of conspiracy theories out there.  What you don’t hear a lot of is conspiracy motives.  I mean, if George W. Bush did this, why?  So he could have a successful war?  Like LBJ?  Did he also plan and execute the first World Trade Center bombing?  The Tanzanian Embassy bombing?  The Kenyan Embassy bombing?  The Khobar Towers bombing?  The USS Cole attack?  Did he create this anti-American sentiment as a clever ruse so one day he could become president and go to war?  This incompetent in chief? 

KNOW YOUR ENEMIES

Or can it be that America has real enemies?  People who resent and envy our life of plenty and freedom?  People in closed societies.  With an illiterate populace.  Who only know what their leaders tell them.  And their leaders lie.  The Soviet Union was such a society (well, a similar society, for they were literate.  But they only read propaganda so the end result was the same).  When a Soviet spy saw how it really was in the decadent West, he or she said screw this and defected.

If we’re speaking of motives, we should be asking what our enemies’ motives are.  For if we do, we don’t have to come up with any wild-ass conspiracy theories.  With them, if it walks, acts and quacks like a duck, it’s a duck.  They hate us.  They want to kill us.  So they try to kill us.  Whenever they get the chance.  It’s pretty straightforward.  Why, even George W. Bush could see this.  And that’s why the bad guys feared him.  He not only dug in his heels, he fought back.  With grim determination.  Unlike his predecessor.  Or his successor.

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