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Saturday, December 24, 2016

Chinese air pollution

I don't get it.  In-so-far as Chinese air pollution is caused by coal fired power stations, smelters and  other factory that spew out particulates and oxides of sulfur into the atmosphere, they could clean up the problem in a historical instant (say 2 years).  America did it and the technology is old hat.  In America the situation was dire.  Once the decision was made, it took them very little time  to stop all this nastiness going into the air.  The technology was patented in1907.

I can't help wondering what the motivation is of the Chinese government.  Is it ignorance.  Is it a lack of concern for their citizens.  Do they want their citizens to die young so they don't have to look after them in their old age.  What on earth is the problem.  They seem to be happy that a lot of their people are smoking so perhaps the last possibility is the correct one.  Anyway, technically, how would they do it.

For the particulates they install electrostatic precipitators.  Let me digress here and try to explain how they work.

Have you ever run a comb through dry hair and then used the comb to pick up little pieces of paper from the table.  What is happening here?  When you rub almost any two different materials together, some electrons are rubbed off one on to the other.  If the rubbed materials are insulators, the electrons or lack of electrons stay on the surface of the two objects giving one a positive charge and one a negative charge.  Opposite charges attract and even a neutral object will be attracted to a charged one as some of the opposite charge on the neutral object is pulled toward the charged object.

Or have you ever shuffled your feet across a carpet and then walked over to a friend and brought a finger close to his ear.  A little spark jumps and so does your friend. You haven't sent much current to his ear but you were at a surprisingly high voltage which caused the spark to jump

Or have you ever got out of a car and as you went to close the door, you got a shock.  Once again a charged object sending a spark to an uncharged one.

In each case a charge has built up on the object and when you bring the charged object near to an uncharged object, electrons jump from the negative one to the positive one and neutralize the charge.  At a microscopic level, if you were a little charge particle, you would be pulled toward any nearby object which was neutral or had the opposite charge.

A lot of this is now done by electronic wizardry but I will describe it old school which is easier to understand.  You may have noticed that in older cars there is a coil.  Ask your granddad about them.  This is a transformer that has a few coils of wire coming from the battery and a lot of coils around it going to the spark plugs.  When a pulse of electricity is sent by the distributor from the battery through the primary (the few coils) it makes a magnetic field which cuts across the wires of the secondary.  This induces a voltage in the secondary.  How high the voltage is depends on the number of coils.  If there are ten times as many coils in the secondary as in the primary, the 12 volts of the primary (from the battery) will be stepped up 10 times to 120 volts. In a car the ratio of primary coils to secondary is much larger in order to get enough voltage to jump the gap in the spark plug.  Actually the strongest spark is created when you stop the current in the primary and the magnetic field it has created collapses.

In an electrostatic precipitator you have something similar except the voltage is stepped up to thousands of volts and you pass AC (alternating current) through the primary.  So far so good but useless.  You have also induced an alternating current in the secondary going positive and negative.  You need high voltage direct current.  No problem.  You rectify this alternating current with a wheatstone bridge.  Note that in the diagrams in the link they talk about resistors.  Replace then with diodes that only allow current to flow in one direction and you will understand rectification.  I'll leave you to puzzle this one out. It is rather neat.

You now have very high voltage Direct current.  You conduct this current to a bunch of spikes, plates or bars in the flu of the polluting chimney and electrons stream off  and attach themselves to the particles.  Once charged, they will be attracted to any neutral or positively charged material.  You then have only to pass this flu gas past, for instance, a wet, grounded surface and the particulates will glue themselves on to the water to be washed away.  Some precipitators are designed to collect the dry particles and shake them off.  Whichever system is used, problem solved.  Particulates removed.

The fine details are somewhat more complicated (aren't they always) but this technology can be bought off the shelf and with her command economy, I'm sure China can reverse engineer it and build a factory to turn these out in the thousands.

As for sulfur, have a look at this link.  Oxides of sulfur can also be removed and the technology is old.  One reason for doing this is  to recover the sulfur which is a valuable industrial feed material.  On the ecological side, oxides of sulfur in the atmosphere attract water and make aerosols of sulphuric acid which are both  toxic and corrosive.  With the recovered sulfur, the cost of a sulfur scrubber is negative (you make a profit on the process).

Incidentally, in a smelter, (factory where metal is recovered from an ore) an electrostatic precipitator also often recovers valuable materials so you often also make a profit on doing the right thing.

 What is wrong with the Chinese bosses.

There is a little wrinkle in this story, though.  Many scientists believe that the particulates in the atmosphere are shading the earth and keeping it cooler than it would otherwise be.  A fairly common estimate is about 2 degrees.  I don't know what proportion of aerosols (air born particulates) are due to Chinese factory pollution but for the sake of the argument, let's say a quarter.  If the Chinese did clean up their pollution, and if the estimates are correct, we could expect a sudden jump of half a degree (centigrade) in our atmospheric temperature.

We should see the results of this experiment fairly soon.  The Chinese population is getting fed up with being slowly poisoned by their leaders who are sitting on their hands.

Saturday, December 17, 2016


Rodrigo Duterte is the president of the Philippines.  He was trained as a lawyer and was a prosecutor in the town of Davao before becoming mayor of that city.  He is much in the news because he cleaned up drug trafficking in Davao by the  rather brutal expedient of shooting drug dealers without benefit of any judicial procedure.  At present he is doing the same for all of the Philippines.  Just recently (December 2016) he announced that he killed drug dealers in Davao with his own hand.  This has shocked the world and politicians all over the world are decrying his actions and his hands-on involvement.

It is interesting to compare and contrast the actions of Duterte in killing drug dealers and those of Presidents Obama and Bush in ordering drone strikes against people they define as terrorists. Incidentally, Obama has ordered many more hits that Bush did.   First the similarities.

In both cases, these are extra-judicial killings.  No trial was carried out, no time was provided to examine the facts and determine if the person was guilty of the crime in question (as defined by the executioner) and no judge and/or jury was involved.  No defense was mounted.   No reference was made to international standards of justice.

In both cases, the killing was carried out in the name of protecting the population from a threat.  In the case of the Philippines, against the clear and present horror of drugs.  In the case of America against the threat of future terrorism.

Now the differences.
Duterte actually carried out at least some of these killings himself.  By admitting he is carrying out this policy and  admitting he has done some of the killing himself.  He has put himself in personal danger by personally confronting drug dealers. 
The American presidents have set others to do the killing who in turn pass the job on to their subordinates who then pass the job on to their underlings.  Even the drone operators are in no danger.  They operate the drones from the comfort of their bases somewhere in the USA.

Duterte, familiar with his local scene, is likely to be hitting the drug dealers he is targeting.  Of course, once you start extra-judicial killings; basically vigilantism; there will be killings of non drug dealers to settle old scores, for pecuniary motivations (protection rackets) and so forth.  Extra-judicial killings are reprehensible on many levels. 
Judging from recent failures of American intelligence, it is likely that the drone attacks are often targeting people with no connection with what America defines as terrorism.  In addition, recent revelations show that America is very casual about hitting innocent by standers.  Bradley Manning is in a military prison, Edward Snowdon is in self imposed exile in Russia and Julian Asange is holed up in an Ecuadorian embassy because of their revelations of these facts.

Duterte, as far as can be determined, has had no part in the drug trade he is hitting.  He is not and has never been a drug trafficker.
America has created the freedom fighter/terrorists she is hitting.    The most recent war in Iraq was based on lie after lie.  Afghanistan create another bunch of so called terrs.  Following the Iraq war, America refuse to let anyone who was a Baathist take part in the administration of their own country.  Since you had to be a Baathist to get a job as dog catcher, this involved pretty well anyone of ability and experience.  What did this cadre of experienced administrators and military men do.  They formed Isis.  So now, America can expend lots of ammunition, make lots of profits for her arms industries, keep her military occupied, justify asking for more of the money from America tax payers and so forth as she kills her own creation.  In the mean time she is into her next war in Yemen, this time by proxy.  She supplies arms and intelligence to the Saudis who are actually carrying out the war.  More terrs being created to keep America ticking over into the future.  The plight of the people of Yemen is heart wrenching.

Extra-judicial killing are reprehensible on many levels.  Much modern thought says any killings, even ones sanctioned by the judicial system are reprehensible.  Here we are comparing the bad with the even worse.  You judge which is the greater crime.

Saturday, November 19, 2016

The car I want to drive

Most major car manufacturers are getting serious about electric cars and most of them are designing cars with all the bells and whistles. I hate to think what they will cost. I believe there is a massive market for a simple, basic, Volkswagen / model T ford / 2cv/Mini - type electric. It wouldn't be for everyone but I believe the market would be huge.

Not only would it be huge in third world countries but also in first world countries. So many of us are fed up with having such a big foot print on the world, fed up with being dependent on someone else to fix our gadgets and fed up with having to tie up a huge proportion of our wealth in a vehicle simply to get from A to B. For other people for whom their very concept of self worth is intimately entwined with driving a fancy car - carry on. Enjoy. The rest of us have a different self image.

Many of us are also a tad suspicious about having every gadget we use being connected to the World Wide Web.  Who wants to be spied on by his toaster (I'm kidding!!!). I suspect we are being spied on by our television sets. (I  am not kidding).  If I want an upgrade to my car, I will pull out, say, a flash drive that goes into a socket in the dash board, take it to my computer and request the upgrade.  Note that many upgrades to ordinary computers smell like idle fiddling by some egg head and often create problems. 

Perhaps I am completely content with the way my car already operates or perhaps I want to wait until some other poor suckers have tested the upgrade before I jump in.  Besides just imagine some bored hacker in his mom's basement hacking some part of the system and bringing a major city to a standstill with gridlock.  Just imagine some foreign power doing the same to your  whole country.  Worse than a nuclear war and leaves the infrastructure intact as they take over.

Of course this also gives Big Brother the ability  not only to follow your every move but to decide to drive your car into a tree or over a cliff at high speed.  You think I am being paranoid.  You have, I assume, being following the revelations of Snowdon and Manning.

I agree most enthusiastically with practically everything Elon Musk is doing and advocating but genius is no guarantee of being right.  Remember a previous genius, Alvin Edison.  He advocated DC (Direct Current) for electrical grids.  Luckily we went with Tesla and used AC.  It is so much more versatile.   Yes, there is a place for DC such as when you transmit power in a cable under water but for the most part, AC is the way to go.

So what would this car be like. It would be both very simple and very sophisticated. Simple in that it would have very few frills, a low selling price and it would be easy for a home mechanic of modest ability to maintain and repair. It would be sophisticated in that it would have the very best engineering and best materials providing reliability, longevity, safety, easy driving, fast charging, recyclability, easy repair and maximum range.

It would be upgradable as new technology became available.  For instance if the new graphene batteries prove to be better than Lithium batteries, when the old batteries finally gave out one could change the batteries to the new sort.  The old batteries would find a new life in private houses to store excess energy generated by your solar panels to avoid sending the power to the grid at knock down prices.  The critical factor is that the new batteries would fit the space where the old batteries lived.

If the engineers insist on producing a hybrid, it would be mostly electrical with a small emergency generator. (a turbine??)   However, consideration should be given to replacing even the emergency generator with more batteries on a weight to weight or volume to volume basis.  So what sort of a car would it be.

The styling would be distinctive.  It would be as recognizable as the  Volks Wagon Combi, Betle, Deux Cheveaux, Model T Ford or Mini.   None of these cars were objects of beauty but they were distinctive.   Clearly it would have to be as aerodynamic as possible and this tends to converge the styling of all cars but there must be no doubt what vehicle you are looking at when you see one of these cars. Easy identification is a big help in making a car iconic. No changes would be made to the styling from year to year. None what so ever. The Beetle didn't need it, neither does our Peoples-Electric.   Not needing to retool for design changes contributes to a lower price.

Driving damage
Bumpers and mud guards should be bolt off and bolt on so that repairing a ding is a simple job of trading in your old part for repair or recycling and bolting on the new part. These easily damaged parts should be compatible for decades. A bumper from the first production model must fit the latest model and vice-versa. Some thought should be given to a hydraulic or pneumatic bumper which could sustain bumps of, say 5 or 10km/h without damage*.

*Nov 2011.  I just read of a jell bumper that a new electric car is using.  Good on you guys.

The Vehicle Manual
The vehicle manual would be straight out of America in their best tradition; the sort of manual that comes out of Time-Life or Readers Digest. They have the most incredible how-to-do manuals where everything is beautifully, clearly laid out and the illustrations are works of art. Once the car had been designed, the wives, secretaries and accountants of the company would be let loose on the car, with the manual, to see if they could change the electric motor, CV joints and anything else that might need to be replaced. If they could not do this, either the manual or the car or both would be redesigned. (No fair changing the secretary or accountant)  A copy of this manual would be standard equipment and would fit in a specially designed compartment in the car.

There would be a standard 'A' tool set and an optional 'B' tool set. The 'A' set would allow one to change a tire and tighten up a screw. The B tool kit would allow most procedures necessary to be done on the car. Very rare tools could be rented from the dealer.  If at all possible the car would be designed to use only conventional tools and to ensure that  a minimum of tools are necessary. The tool kit would fit in a specially built-in compartment in the car.

The Body
Have a think about a carbon fiber reinforced thermoplastic body.  It may not be practical yet but look up the item on YouTube by Amory Lovins in which he shows his audience a half dome of the material and gives them a sledge hammer to see if they can break it.  The car body could go together like pop beads with a smear of epoxy, eliminating all that welding.  The  material is naturally rigid and sound absorbing and able to survive severe crashes while protecting the driver.

The Chassis
Initially there would be only one medium size chassis but eventually there would be three sizes: small, medium and large. On to each of these chassis would bolt the body of a pick up truck (Ute, Bakkie, Tender), a family car, a people mover (van, Combi) or a sports car..... Well maybe not a sports car on the largest chassis but certainly on the medium and small chassis.  Perhaps with modern materials and technology, we might have mono-cock cars with no chassis.

Wrecked or scrapped cars could be taken apart for parts and the parts would fit on any other car no matter what the vintage. Also, in so far as possible, fittings from one size of car would fit on the other sizes. All, for instance, would use the same head light bulb, door handle, radio mounting and so forth.

Yearly Model Changes

This ridiculous system of planned
obsolescence must be made obsolete .

Steering gear
Lets go for simple rack and pinion.  Check out all the cars that used this system and adopt the best one.  Power steering uses power and in a reasonably light car power steering is completely unnecessary.  Besides, Rack and Pinion is cheaper and easy to repair (if it ever needs repairing).  Our Peoples Electric will tend to be a light car with all the frills removed and eventually, as the technology allows, thermoplastic carbon fiber bodies. Rack and Pinion steering will be perfectly adequate.

Nothing wrong with wind up windows but make them of quality material so that they wind up smoothly when you buy the car and just a smoothly in 20 years.  Remember, no planned obsolescence.  Electric windows use power and are more expensive to build and repair than mechanical windows.   

OK you can have your electric windows if you insist but that is a far as I am prepared to compromise my people's electric.

Car Magazine
A quarterly car magazine would give interesting hints on how to maintain your car, maps of places to exchange or charge your batteries and quirky stories of how someone had crossed the Sahara with the car fitted with solar panels and how someone else had fitted a chuck wagon stern to his vehicle and gone on roundup.  It would be interesting, informative amusing and iconic. It could be delivered to your reading device or in a paper form if you prefer.  Some of us Luddites like paper.

Solar cells
Solar cells must eventually be fitted on every possible surface.  The technology is probably not there yet but is advancing rapidly.  Very interesting work is being done on allowing all panels to contribute their full generation capacity despite a lack of co-linearity and despite some panels being partially shaded. When we have power point tracking for individual solar cells, these technologies will greatly increase the effectiveness of the solar cells which clad the car. At one time solar panels were stiff and flat.  Now one can buy flexible panels.  It should soon be possible to clad any shape and get the full power from each cell.  In addition there is work on producing power from windows.

 Note that the solar panel retrofit on the Prius on the roof between the front and rear window is reputed to give about 10 km extra for a day in the sun. A nice little bonus. With advances in the technology and panels on the whole car, one might get, say, 25 extra km per sun-day*. We're not talking here about a completely solar car.  Just a nice little bonus for a day in the sun and the possibility of getting home if you forgot to charge and ran out of gas (sorry - electricity)

*Note that since the writing of this article there has been an item in the news (The NZ Press, feb 2010) that IBM has developed a solar panel using only "easy to find" minerals. If this development becomes commercial, the cost of solar panels should plummet even further. They already are on a toboggan ride.  Standard panels coming out of China are already (2012) down to a dollar per nominal watt.

Mechanical Design
The designers would endeavor to use the most commonly available parts much like the Skunk Works does. The Skunk Works only innovates parts that are necessary for the special functioning of the aircraft in question. The rest is off the shelf. If a certain tire rim with a certain spacing of stud is the most common in other cars of the world, this size should be adopted. If a certain head-light bulb socket is most common all over the world, this one would be used and so forth. This would ensure that if you were stuck, you would have a good chance of finding parts that would get you by. Conversely, scrapped cars of this type would be a rich source of parts, even for other makes. Even better for the company, people with other types of vehicles would always try to buy from the company because of the high quality and competitive pricing of their parts.  Having your parts fit other cars would ensure a large market.

None, Nada, Zilch. This may sound revolutionary..... and at first, not having a warranty would be a negative selling point. At the very least, make it an optional extra.  As confidence builds up in the reliability of the car, people will relax about the lack of warranty. In fact, a lack of warranty will quickly become a major selling advantage. 

Warranties cost the company money and this is built into the price of their vehicles. The savings from the lack of warranty must be passed on to the customer. An added effect would be that people would not thrash their car during the warranty period. They would look after their cars from the start.

Besides, as mentioned above, the cars would be so easy to repair that any joker with a basic set of tools and the manual could repair any part of the car. By their nature, electric cars will be far simpler than petrol cars.  Moreover computer boards are simply unplugged and reprogrammed or a new one plugged in.  Computer chips are as cheap as,,,,, well chips, and software when spread over many users is also cheap.

Dealers would locate in the low rental industrial areas of cities or towns. Only one dealer would be allowed per city or town. In their warehouses they would sell the cars and have a full stock of spares. They would never ever ever ever run out of spares. Their computer system would flag when they had to order parts to keep their inventory up to date. A dealer who couldn't do this would loose his dealership. All dealers and their staff would be sent to the factory to practice doing everything on the car that could be done but they would not be required to do repairs at their dealership. They would be there to provide advice and parts.

Undoubtedly, there will be  computer chips in the car. How about using one of those computer memory sticks (flash drives) that people use to transfer information from computer to computer. Have it plug in to the dash board. Taking it out and plugging it into your PC would run a diagnostic and you could reprogram the chip for maximum efficiency or maximum performance or for whatever other options were available right from your PC.  Hardware is expensive.  Software, when spread over many units is cheap.

The Battery
This is out of the hands of the company but every effort should be made to standardize batteries between different makes and models of cars. For instance, the battery of a Tesla should fit a Volt and vice versa. It would be well worth while looking at the Project Better Place option.  At the very least, a new company developing an electric car could adopt the battery design of other cars right from the outset and build the car around that design.

Apparently the lithium ion battery is now obsolete and the Lithium titanate, lithium iron phosphate and lithium polymer batteries are far longer lasting.  The polymer battery, is apparently much lighter.

Graphene batteries are on the horizon with the discovery that with an addition of water, the layers of grapene do not fuse.   Batteries can be upgraded as technology allows but can still have the same outer aspect so that they can be used in older vehicles. The batteries might be based on a standard cell of 2x3x5 cm that could be combined in series and parallel to achieve whatever voltage the particular car uses and combined in different physical configurations to fit virtually any available space.  Incidentally, such batteries would find uses in a wide variety of other applications including power storage for the home.  There would be a huge market for both new batteries and batteries which no longer had the capacity to be used in a vehicle.

All components of the car must be designed to be completely recyclable. All parts will have a core charge just as is done with glass bottles and given back when the part is returned. This would ensure that worn out cars would not litter the environment. People who are too rich or too lazy to recycle their vehicles would find any number of people who would take the vehicles off their hands to recycle parts or to get the return fee.

A great beauty of electric cars is not only that you save on fuel but also on lubricants. An electric car can be built today that needs no lubricant except perhaps a little 3 in 1 oil for the door hinges. Remember all the grease points we used to have to attend to at each service. These don't exist on modern cars.  Electric cars do not have an oil sump.  More saving of our too-valuable-to-burn fossil fuels.

Electric motors are so reliable that one could have a car quite soon that would last almost a lifetime. You would probably change the upholstery 4 or 5 times before the car wore out. Israel is about to convert to electric cars provided by Renault-Nissan with reticulation and battery exchange provided by Project Better Place. If successful, this will cause a paradigm shift in the car market. A very attractive option is to for a new car builder to build a car with a battery that can be changed by Project Better Place stations*.

 *It appears that the Project Better Place company has been bought and shelved.  This smacks of interference by the oil or conventional car companies.  They are fighting a rear guard action and will loose in the end.

The world is ready for a simple affordable car. Renault is now building the Logan which already goes some way towards a "peoples car" and demand has outstripped anything the company expected. Of course it is a petrol car but they have tapped a market that they didn't know existed. Renault has been absolutely amazed by the response of the public in France. Tata in India has done the same. Obviously a simple car is not for everyone but all over the world there is a longing for simplicity, for having a smaller footprint on the world and for being able to look after yourself rather than having to depend on a specialist for all your needs. If Renault "keeps the faith" and isn't tempted to slowly turn the Logan into a conventional car, it will sweep the world. By the time other manufacturers wake up and smell the flowers, the Logan should have captured the imagination of the world and a huge chunk of its markets. How much more would a simple electric car capture our imagination.

Self Driving
No no no!  I don't want a car that drives itself.  I like driving.  I certainly don't want my car connected to the world wide web.  Have you any idea the vulnerabilities we are exposing ourselves to by putting all our activities into the hands of 'big brother'.  How exposed we are to being hacked, not only by some 14 year old kid in his mom's basement but by government agencies.  Give me a simple but well engineered car and if possible one that I can maintain myself.  Make it highly recyclable.  If as many scientists predict, we are heading for a collapse of our civilizations which will put us back at least into the dark ages, any idea how valuable an electric car will be, after the crash, that you charge at your own solar panels on your roof and that doesn't depend on a www that has collapsed.

And finally
If a car manufacturer does this, eventually it will have to down-size. Such a car will saturate even the world market and The Company will then be providing top up cars and parts. And ultimately, isn't this what we want: a much smaller car manufacturing sector, using less raw materials and energy and producing usable, long lasting cars for the public. We are just on the brink of an ecological melt down and must reduce our foot print on the world. We don't all want to be living the way the kids were in the winner of this year's (2009)Oscars*.

*Slum Dog Millionaire

What is certain is that the car manufacturer that twigs on to this philosophy first will capture a huge share of the market.  If this car comes from America, the world is their market.  If it comes from some other country, America and the rest of the world is their market.

Saturday, November 5, 2016

Some basic science

If you want to  to make sense of the weather, the climate and climate change, at the very least you need some basic science.  As our education curriculum gets more and more crowded by IT and other subjects, many of these concepts are not being taught and they are interesting.  Way back, when I was in High School, the basics were taught and became part of our core knowledge.  (Sorry to sound like an old fart but I guess I am)  So hear goes.  No particular order.  I will type them as I think of them.

Sensible Heat (as in 'to sense something' - not that the heat is somehow morally superior to some other unsensible type of heat)

This is the heat that it takes to raise the temperature of something or the heat that must be removed to cool something.  The small calorie (with a small 'c') was defined as the amount of heat needed to raise one gram of water by one degree centigrade.   There is also a large Calorie (with a capital 'C') which is the amount of heat to raise a kilogram of water by one degree.  Clearly since there are 1000 grams in a kilogram, there are 1000small calories in one large Calorie. Incidentally, if you need to work in SI units, One calorie (small 'c') is equal to 4.1813 joules*.

*A Joule is one watt second.  In other words a watt (of electricity) acting for one second.  If a one watt heater was immersed in a gram of water and operated for 4.183 seconds, it would heat the water (assuming no heat loss) by one degree C (or K if you like).

Latent Heat 
I defined sensible heat first in order to make it easier to define Latent heat.
Latent heat  is the amount of heat needed to melt or evaporate a substance or conversely, the heat that must be removed to condense or freeze something.  
This is a core concept when talking about weather and for a whole range of other subjects.  I'll use the old calorie units here because it makes the explanation easier. 

When you melt ice, it takes a lot of heat. Specifically 80cal (334j) per gram.  This is the same amount of heat that would be needed to raise a gram of water from 0 degrees   to 80 degrees C.  Conversely, when water freezes, each gram gives out 80 calories.  Some people ask; "so if heat is given out, doesn't that warm the water".  No, but to a good first approximation, it keeps the water at zero degrees until all the water is frozen.  Similarly, when you boil water, it stays at 100 degrees while the water is being boiled off.

The energy needed to change  liquid water to water vapor is even greater.  To evaporate one gram of water takes 532 cal (2264j) or enough heat to raise a gram of water from 0 degrees C to boiling 5 times over and then a bit.  Of course, when water vapor condenses into a liquid this same 532cal is given out.

Since we have these two, we can add them and find the heat of sublimation.  This is the heat needed to change solid ice to a vapor directly without going through the liquid phase.  This is 532+80 =  612cal (2598j) per gram of ice.

As an interesting corollary* of this: if moist air blows across ice and the cooling of the air by the ice causes the water vapor to condense out as water, every kg of water condensed out of the air will melt 532/80 = 6.65 litres of water from the ice.  Think of a moist foen wind blowing across Greenland for instance.

*A corollary is something that results directly from some previous fact(s).  Usually used in Math.

If you look at the table in the link above, you will note that two substances, Ammonia and Water have much greater phase change energies (latent heat) than other substances in the table.  The reason is of interest.

You have probably heard of the experiment of Earnest Rutherford who worked out that atoms are not like plumb puddings but more like solar systems.  Most of the mass is concentrated in the center and most of the rest of the atom is empty space.  The solar model was an improvement as far as it went but later it was worked out that while the so called 's' sub orbits were pretty well circular, the 'p' sub-orbitals were dumb bell shaped.     In water, the hydrogen attaches to the ends of two of these dumb bell sub orbits making the water molecule an angular shape.  Move your thumb and index finger as far apart as you can and look at them.  The Oxygen atom is located where your thumb and fore finger join and the hydrogen atoms are on the ends of the finger and thumb.

The electrons spend much of their time around the oxygen atom leaving a naked proton at the other "end" of the molecule.  Not only is the water molecule charged (positive at the Hydrogen side and negative at the Oxygen side) but there are no electron orbits closer to the hydrogen nucleus to keep other molecules away.  A negative charge can get much closer to the Hydrogen end than with other atoms and hence the bond is stronger*.  This is the famous Hydrogen bond.

*In general, a force field decreases with the square of the distance from the object creating that field. 

This is the explanation why it takes so much energy to melt or evaporate H2O.  The water molecules, because they have a positive and a negative side, cling together.  This is also why their melting and vaporization temperatures are so high compared to other molecules of a similar molecular weight.

Incidentally, if you want to visualize ammonia, spread your first two fingers and your thumb far apart.  The Nitrogen atom is where they all meet with the three Hydrogen atoms on the ends of your fingers and thumb.  Just like water, ammonia has a positive and a negative end (side) and the positive ends are naked hydrogen atoms (protons) and hence form the famous hydrogen bond.

You might wonder how a molecule of water can leave the surface of the water and go into the air. After all, it is at the temperature of the water and the molecules cling together.  It is a little like a rocket leaving the earth.  It has to have enough energy to break free of gravity.  The water molecule has to have enough energy to break free of the electrostatic attraction to other water molecules. The answer is that temperature is a measure of the average energy of the molecules As they bounce off each other, as long as energy is not being added or removed from the body of water, the average energy stays the same.  However this is only an average.  As they randomly bounce off each other, there will be some that have more velocity and some less.  Some molecules on the surface will have enough energy to rocket into the air.

Incidentally, this is the explanation why evaporating water cools the surface it is on.  The energetic (hot) molecules leave, leaving behind the less energetic (cooler) molecules.  They absorb heat from the surface they are on and in turn some of the energetic ones rocket into the air.

Avogadro's Number
Some genius worked out that a given volume of any gas at the same temperature and pressure contains the same number of molecules. (it wasn't Avogadro)  Oxygen exists in the air as a molecule of two oxygens joined together as does hydrogen and nitrogen.  This is rather convenient since if you know the molecular weight of any gaseous molecule, you know it's relative specific gravity (how heavy it is compared to other gases).

Hence, Oxygen has an atomic weight of 16 (rounded up), it's molecule is 32.  Nitrogen is 14 so its molecular weight is 28 and water is 16 plus 2 equals 18.  Air (very approximately) has a molecular weight of 30 (between Oxygen and Nitrogen*).  Water vapor therefore has a density of 18/30 = 3/5th or 60% of air.  Counter to what might think, a mix of air and water vapor (humid air) is  lighter than dry air.

* I haven't taken into account that 4/5th of air is N and 1/5 is oxygen or the actual mollecular weight of the gasses.  This would alter the calculation slightly.  The above is what one calls a first approximation.

Note here that when you dissolve sugar or salt into water, the solute (solid) to some extent fits between the water molecules so the volume of the resulting solution is less than the volume of the original water plus the volume of the original solute.  With gas this is not so.  If you add a gas to an existing gas, it increases the volume by exactly the amount that you added.

Ignoring the Fahrenheit system that only a few primitive societies still use, the centigrade system is as follows. (conceptually - there are a few minor whichevers and we will have a look at them later).

Using a thermometer, you mix ice and water and note where the liquid in the thermometer settles down.  You make a mark and call this 0 degrees Centigrade.  You then boil the water and once more make a mark where the liquid comes to in the shaft of the thermometer.  You call this 100 degrees Centigrade.  You divide the difference into 100 gradations.

Absolute Temperature
Using the same gradations you go downward until you can't remove any more heat from whatever substance you are examining.  You find that as low as you can go is about 273 degrees below the freezing point of ice.  This is called absolute zero and is a point at which no more heat is held in the substance. In Kelvin,(the absolute system)  the freezing point of water then becomes 273K and the boiling point of water 373K

A way of getting a first estimate of absolute temperature is to cool a gas and note its volume as you hold the pressure constant.  Draw a graph.  Where the volume goes to zero is a good first approximation of absolute zero.

How about the whichevers.  First then a word on isotopes.

The nucleus of atoms contains positively charged protons and no charge neutrons.  The neutrons, somehow hold the protons together from flying apart. Don't ask me how.  That is above my pay grade. The protons are all positively charged and you might remember from science that same charges repel each other.  In any atom, there are approximately the same number of neutrons and protons.  This is not quite correct and becomes a little less so for the heavier atoms but it is a fair first approximation.  A given element, let's say Carbon, always has six protons.  This is why it is carbon or to be more accurate, it has the same number of electrons as protons and 6 electrons results in the physical and chemical properties that we know as carbon.

However, within limits, it can have various numbers of neutrons.  Carbon can have 6, 7 or 8 neutrons and hence Carbon 12, Carbon 13 and Carbon 14.  Carbon 12 and 13 are stable but Carbon 14 is not.  If you have an atom of Carbon 14 it will at some point fly apart.  You can't know when this will happen for any given atom but it has been observed that with large quantities, you know how much of the carbon 14 will break down in any period.  It turns out that half will break down in 5730 years and half of the remaining half in another 5730 years and half of the remaining quarter in another 5730 years.  This makes it very useful for dating organic material and I will explain this later and give you the math needed to date objects.  It is not difficult.

You might wonder why there is not an equal amount of Carbon 12 as 13 if both are stable.  I don't know.  Carbon 12 is far more prevalent.  Perhaps for some reason more Carbon 12 is produced in super novas that carbon 13.  If someone knows, put a note on the bottom of this  blog.  

Most elements have a number of isotopes and some are stable and some are not.  The unstable ones have half lives which vary in the different elements from miliseconds to millions and millions of years.  It is not always the heavier that is the most unstable.  For instance Uranium 235 is less stable than U238. Apparently certain configurations are in a sweet spot.  The search carries on to find trans-uranic elements which have sweet spots.

So back to Temperature
Water can be made from any of the isotopes of Hydrogen and Oxygen. Hydrogen has three isotopes, namely ordinary hydrogen with one proton in the nucleus, Deuterium with one proton and one neutron in the nucleus and, you guessed it, Tritium with one proton and two neutrons.

Oxygen has three isotopes, O16, 17 and 18.  Since she has 8 protons, these isotopes have 8, 9 and 10 neutrons in the nucleus.  In this case, O16 is the stable one. (often although not always, the lighter one is the stable one.) So what does this mean.

If the lightest Hydrogens reacted with the lightest Oxygen, you would have a molecule with 18 nucleons.  This is as light as water can get.  If the heaviest of both linked up you could have a water molecule with 24 nucleons.  Since virtually all the weight of an atom is due to the nucleons, you can have a wide range of weights.  Say for a first approximation that all the atoms in the water you are using to establish your thermometer have the same energy.  To have the same energy, the lighter molecules are moving faster. (energy is equal to half the mass times the velocity squared) so they will more likely have escape velocity if they find themselves at the surface of the water.  So what happens.

The light molecules fly off preferentially leaving the heavier molecules and as you continue to boil the water, the temperature rises.  The reverse is also true. The heavier molecules of water condense more easily (at a higher temperature) than the lighter ones.

This, of course, makes the calibration of a thermometer a tad difficult as the boiling point of water (if you want to be picky and scientists are very picky) keeps changing as you boil it.  Of added difficulty, some sources of water have slightly different proportions of isotopes than others.  

Boyls Laws
These are pretty simple and also come from observation.   Simply stated they are as follows.

If you increase the pressure on a volume of gas, the volume decreases.  If you double the pressure you half the volume.  Nature could have given us some other relationship between pressure and volume.  Isn't it nice that it is such a simple relationship.

If you heat up a gas, its volume increases.  Here though, we are talking about absolute temperature.  If you double the absolute temperature, you double the volume. (if the pressure is kept constant). Again, nice that nature provides such a simple relationship.

For instance if you were to raise the temperature of a gas from the freezing point of water to the boiling point of water you would increase its volume by 373/273 or by about 1.366 times.  (that is why I told you about absolute temperature first).

The earth is about 25000 miles around its equator.  It rotates on its axis once a day.   Hence if you are standing on the equator you are traveling at about 1000miles per hour eastward.  If you were standing on one of the poles, you would rotate once per day but are moving at 0 miles per hour (we are in an earth reference frame).  Of course the earth is moving through space and you with it but that is neither here or there for this example).  If you fire a cannon ball northward from the equator in the northern hemisphere, In addition to its northward velocity, it is traveling sideways toward the East at 1000mph.  It will still be traveling toward the East as it flies through the air but the ground over which it flies is traveling slower and slower, the further north you go.  Looked at from above, the object veers to the right in relationship to the earth below.  As you can see, the effect is greater, the further north you go.  If you go from the equator to a degree north of the equator, the sideways velocity hardly changes.  If you go from one degree south of the North Pole to the North Pole, the change in velocity is large.  The same occurs when you move something southward in the Northern Hemisphere.  It veers to the right.  This effect has some profound implications on our weather.

Radioactive dating
As I mentioned, radioactive isotopes break down into simpler atoms.  Certain proportions of protons and neutrons in the nucleus are not stable.  It was observed fairly early on that if you measure the time it takes for half of the radioactive isotope to break down, then half of the remaining will break down in the same time, half of what remains in the same time and so forth.  This is called the half life.  I'll use Carbon as the example since it is valuable for the dating of organic material. Carbon 14 has a half life of 5730 years.  You might ask, if it has a half life so short in comparison with the age of the earth, how come there is any of it around now.  Also, you would have to know how much was in a living organism when it died in order to measure how much there is now and use these two figures to date it.  The answer is rather neat.

Carbon 14 is continually being produced in the upper atmosphere by an atomic reaction.  When high energy cosmic rays hit Nitrogen 14, some of it is converted into Carbon 14.  To a first approximation (more of this later) its rate of production has been constant over time.  Living organisms incorporate carbon into their bodies throughout their lives but when they die, no more is taken in.  The Carbon clock starts and if you can measure the proportion of Carbon 14 in relation to "ordinary" carbon, you can tell the age of the artifact.  Now for the math. Co is the amount of carbon in the artifact (piece of wood) at time zero.  That is to say, when the wood died and stopped taking up carbon.  Ct is the amount of carbon at time 't'.  That is to say when you took the artifact and decided to measure it.  1/2 is just what it says.  One half.  and 'n' is the number of half lives that have gone by so we have the formula.

Ct=C0 X (1/2)n. Also written in algebra without the times sign as Ct=Co(1/2)n

Lets look at this.  Suppose you start with 8 grams of a radioactive element and one half life has gone by.  You raise 1/2 to the first power which leaves it as 1/2 and multiply by 8.  Answer 4 grams.  Suppose two half lives have gone by.  You raise 1/2 to the second power (multiply 1/2 by 1/2) and you get one quarter.  Multiply this times 8 grams and you have two grams.  Let's do one more.  Three half lives have gone by.  You raise 1/2 to the third power (multiply 1/2 times 1/2 times 1/2) to get 1/8.  Multiply 1/8 times 8 and you get one gram.  So this formula works.  Now let's make it a little more sophisticated.  We will define 't' as the time that has gone by and 'h' as the half life of the isotope we are working on.

Clearly the number of half lives that have gone by equals t/h. Say the half life of an isotope is 10 years and 30 years have gone by.  Clearly three half lives have gone by.  In other words n = 30/10.   We can now substitute this into our first formula.  Where we had n we will put t/h so Ct = C0 x 1/2(t/h).  

 Now we have the formula in what I call the forward or straight forward form. In other words in the form that is easily understood, we can now "solve for" any of the terms. In other words make t or n or Co the subject of the formula. If you remember your algebra, since the right side is equal to the left side, as long as I do exactly the same to both sides, the formula will still be valid. I could multiply both sides by some number, square or take the square root of both sides and so forth.   The trick, of course,  is to choose the correct thing to do to both sides to get the term I want as the subject of the formula.  Why bother. Well, sometimes I might want to work out the age of the artifact 't' or the half life of an isotope 'h' so it is useful to change the formula around to make the desired factor the subject of the formula.  Of course to work out 't' or 'h' I would have to know the value of the other terms in the equation.

Let's solve for 't', the time that has gone by.  Then we will have a formula we can use for dating an artifact.

I start with the formula Ct = Co x (1/2)t/h

I divide both sides by Co resulting in

Ct/Co = 1/2(t/h)

Now you will have to take my word that the following identity is correct.  To explain logs at this point would take a tad too long.

logABC (log to the base A of B to the Cth power) = C x logAB (C times log to the base A of B).  In other words, you can put the exponent before the log and the value remains the same.   So first we will take the log of both sides.  You don't have to understand logarithms but only the principle that if we do the same to both sides of an equation, the formula is still correct.

Log10(Ct/Co) = log101/2(t/h) 

Using the conversion (moving the exponent, (t/h) in front of the term on the right side, I get:

Log10 (Ct/Co) = (t/h) log10(1/2)

Now to get t by itself, I simply divide both sides by (log10((1/2)) and multiply both sides by h to get: t=hlog10(Ct/Co) / log101/2

I said that this was a first approximation.  It was seen that the value obtained for objects of known age differed slightly from the theoretical value.  For instance, in the high mountains of America is a species of tree known as the Bristle Cone Pine. As with many trees it has growth rings and live trees have been found that are 5000 years old.  In addition, in the area, there is dead wood which with Dendrochronology can take the age back another 5000 years.  Carefully shaving off individual growth rings and carbon dating them showed a small variance from the theoretical value.

The best explanation for this is that the rate of C14 production has not been exactly the same over time.  Cosmic rays come from violent events in the universe and have varied over time.  What is good, though, is with the application of this correction, the age of artifacts of known age slotted into place.

Saturday, October 22, 2016

Training and job creation

While I was lighting the log burner this morning, I paused to read an article on a paper I was using to start the fire.  The article was on the connection between training and jobs.  The article suggested that all that is needed to get the unemployed working is to give them the appropriate training.  Fine as far as it goes but it is missing the point by a country mile.

As long as there are no jobs to go to, all we create is some better qualified out-of-work people or people who will leave the country to somewhere that jobs exist or remain in the country, drawing welfare and assaulting their wives and children from the frustration of not being able to provide for them.

Here in New Zealand, we have been both throwing away existing jobs and ignoring obvious measures we could take to create jobs.   I'm pretty sure what the motivation is but more of that later.  Let's examine some concrete examples.

Our Fisheries
You would think that a sophisticated, modern country like New Zealand would fish her own waters.   We have one of the largest Exclusive Economic Zones in the world and definitely one of the largest in relation to the size of our country. Only a couple of the Island nations of the Pacific have larger economic zones in relation to their size and none come near to the absolute size of New Zealand's economic zone.  Instead, of looking after this vast resource, what do we do.

We allow foreign fishing boats to fish in our waters, many of them from Korea,  employing desperate workers from third world countries.  The abuses of these workers by their Korean officers have been an ongoing scandal in New Zealand and there is a case in our courts at present with a couple of confiscated boats been held until the Korean fishing companies pay the wages promised to their workers.  The treatment of these indentured workers has been beyond belief.  The ones that dare to talk, have told  of workers even being killed and tossed overboard.

The New Zealand government in her usual fashion has put a sticking plaster on the problem and insisted that all boats that fish in our waters must be registered in New Zealand.  Cameras have been installed in some, but far from all, boats.  In cases where the cameras have shown violations, they have been completely ignored by the government.

We even had an observer on one of the most abusive boats and somehow, her information never got to the appropriate officials or they ignored what she said.

And do you think that these foreign fishing boats look after the fisheries resources of New Zealand.  Of course not.  The first of these boats that was revealed to be treating her workers abysmally was later found to have caught a particularly valuable net of fish and so jettisoned her already frozen catch to make room for the more valuable fish.

And do we really think that they land all their fish in New Zealand as is required by the New Zealand regulations.  Pleeeese.  Give me a break.

We are in danger of following the Canadian example.  On the Grand banks off the coast of  Newfoundland, the Canadian Fisheries Department, one of the most sophisticated in the world, cow-towed to crass commercial short term interests and allowed that legendary fisheries to be destroyed.

 If we restricted fishing to our boats, the fishing pressure would lessen, stocks would increase and our own fishing boats would find a very nice increase in their catch-per-unit-effort.  In other words, their boats would be more commercially viable. Politicians are not expected to be fisheries experts but at least they could listen to those that are.  At least they could show a little simple common sense.

Our Rail Stock
New Zealand has entered into an upgrade of our railways including engines and other rolling stock.  What a great move in an era in which we must reduce our output of Carbon dioxide into the atmosphere.  Even if these are diesel engines, their output of Carbon dioxide per ton-kilometer of goods moved is far below that of trucks.  When we use electricity to power our engines the reduction is truly amazing.  New Zealand generates about 70% of her electricity renewably and rising*

*note that in a recent extensive poll in the UK, 73% of the population, both rural and urban, said they were very much in favor of on shore wind turbines while at the same time the government promotes nuclear and fracking.  Something rotten in the state of UK here.  I bet our stats would be similar.

We could eventually go the extra mile and have containers, carried by rail, delivered to their end destination by electric trucks.

So what do we do.  We contract to have the rolling stock built overseas.  The NZ Rail workshop in Dunedin and the city of Dunedin commissioned a report by the BERL institute to calculate if this would be a good thing to do.  The bottom line of the report was that with all the spin offs to the New Zealand economy, we would have to be able to obtain the rolling stock for 38% of the local cost before it would be worthwhile to buy them overseas.  Think taxes going into the exchequer from all the workers in the NZ rail workshop and all the sub contractors, Reduced welfare payments for people now not out of work, efficient repair and maintenance and so forth.

But the spin offs would have gone far beyond this.  Our manufacturing industry would have had to upgrade her construction techniques, electronic capability and a whole range of other skills to make modern rolling stock.  All this added capacity would have spun off into other industries.  Who knows.  We might have even eventually started to produce The Affordable Electric Car, called, of course, the Kiwi.

Mind you, we mustn't be too starry eyed about our own KiwiRail workshops.  I live in a railway town and some of the old timers tell of the incredible abuses of their position that occurred some of the workshops with engineers using the equipment during working hours for their own businesses, not turning up for work but getting paid and so forth.  I have no idea if such practices were common recently but it is hard to get back a reputation lost.

Our Lumber Industry
We have just had a massive (in terms of the damage it did) earthquake that trashed Christchurch.  In the early days of Christchurch, there were some tremors and people built as best they could at the time to survive earthquakes.  However as usually happens, we forgot or thought, somehow in one of the most seismically active countries of the world, it wouldn't happen again.  We started to build with unreinforced masonry.  The inevitable happened.  When a relatively small earthquake happened right at the south of Christchurch where the flat meets the banks peninsula (an extinct volcano), the vertical acceleration was an incredible 2g and buildings fell right and left.  What an opportunity.

The most resilient material to rebuild the city is engineered wood.  That is to say, laminated beams for the skeleton and engineered wood cladding for much of the rest.  In Vancouver Canada, I saw a 7 story building going up, completely of wood.  What an opportunity.  We could then have been levering off this experience to send custom engineered wood to other earthquake prone countries to build or rebuild their structures.  Instead what do we do.

We sell our raw logs to China and receive value added products made from our own wood back from them.  Our mills have been closing in droves and we hardly have an industry left compared to what once was.

Incidentally, China has an interesting "ploy" she uses in this and other industries.  I can't swear that it is done on purpose or if it is just the way things  happen but here it is how it unfolds in relations to our lumber industry. Put milk powder, meat or any other commodity in place of logs in the following paragraph and you are pretty well on the money.

China has huge monetary reserves from selling their goods to America and other countries.  This money is devaluing from day to day and is likely to crash at some point.  America is deeply in debt, a highly corrupt society and if they loose their status as the holder of the world's reserve currency, the dollar will plunge in value.  China knows this and wants to trade this ephemeral wealth for solid value.  She pays top dollar for our logs and of course, is competing with our local industries.  It is a free market so, of course, our loggers sell the logs where they can get the best price.  This causes our whole down stream wood industry to collapse.  Then what happens.

China, generously proposes to build a large modern lumber mill in New Zealand and of course ensures by doing so, a vertically integrated supply of wood for her country in which she can take the profits in China instead of New Zealand.  And we are immensely grateful to them for doing this. (this is not what might happen, it is already happening).  Ditto with milk products.

These are just three examples but you can see the trend.  What we need is a government with concern for the bulk of her citizens and a vision that extends to more than a 4 year election cycle.

Friday, September 30, 2016

The Otter river Beavers of England

In a previous blog, I wrote about the Tay-catchment beavers in Scotland.  Now the English have got in on the act.  A couple of beavers 'appeared' in the Otter River, on the South Coast of England in Devon.  This has resulted in three breeding pairs at present (Sept 2016).  In a great move, the Powers-that-be have allowed the introduction of a second pair further up in the catchment so that when the two populations meet, there will be greater genetic diversity in the united populations.  First a little information on where you can see these beavers.

You head for Devon on the South Coast out toward the West and set your navigator to Otterton.  It is a village near the mouth of the Otter River.  There are a number of places you can stay and I can heartily recommend the Kings Arms.  Book ahead because tourism is picking up with people coming to see the beavers.
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Kings Arms in Otterton

To see the beavers, I would highly recommend getting there before first light in the morning.  You will also see beavers in the evening and even occasionally in the middle of the day but morning seems to be the best time.  Starting from the Kings Arms, you walk west along the main road (back the way you entered Otterton) past a working flour mill on the left and across the bridge that crosses the Otter River.  Just past the bridge, you will find a gate on your right and beyond the gate a well trodden path.

Head upstream (downstream is also a nice walk and you can walk along side a wetland and down to the sea).  As you head upstream, you will pass a weir that directs water to the flour mill in Otterton.  It has a fish ladder built into it.
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Otterton flour mill weir with fish ladder

A short way further on you will pass a wooden bridge over the Otter.  It arks up to the East side which is considerably higher than the west side where you are walking.  From here on, keep an eye on the small trees to the left of the path.  You will see beaver cut branches here and there.
Wooden bridge across the Otter River

Keep going (20 minutes to half an hour from the gate at the start of the path) until you come to a well trodden place on the side of the river.  If you sit on the edge of the river and look upstream you will see a bed of bull rushes and on the East side of the river, a small beach.  The beavers often haul out there.  If you look a little way down stream, you will see a pile of branches up against the far bank.  This is where their burrow* is located.

* When first introduced to a new area, beavers often make burrows in the river bank for raising their young.  Later, when they dam feeder streams, they construct a lodge in the pond they have created for their nest.

In larger rivers, beavers make burrows in the bank. 

At present (Sept 2016), the adult pair at this location have five kits.  Generally when beavers are introduced to a new area, their population expands at about 25% per year.  This only requires one surviving kit every two years.  Clearly the potential for an increase in population is much greater.  The kits stay with the parents for an additional year and help them to look after the next batch of kits.When the adults are building dams, lodges and food stores, they help with this too.  They become sexually mature around the end of the second year and the parents drive them out.

A second place you can see beavers is from the middle of the wooden bridge.  You may need a pair of field glasses.  Look upstream to where there is a wee beach.  They often haul out there.

Before I start, have a look at these beavers.  This footage was shot by Sylvia Meller, wild life photographer extrordinaire.  I had gone to England with no thought that I would be able to go and see the beavers of Devon and didn't have a camera with me.  Spot the dummy.  However these pictures are far better than anything I could have shot.  Look up other works by Sylvia.  They are great.

The territoriality of beavers, the fact that they drive out their young after they have reached maturity,  has an interesting consequence.  Once the available location in rivers and streams are occupied, the population overshoots slightly each year and then falls back to its carrying capacity.  Unlike many other animals, you can't have a population explosion of beavers.

A caution
The beavers in the Otter catchment are becoming habituated.  That is to say, they are becoming used to humans.  Like any mammal they learn and as long as they aren't harmed by humans, they will show their natural behavior in full view.  This presents a magnificent opportunity for school trips with all the ecological opportunities any teacher could ask for.  Beavers are shy creatures but can become very tame.  Just one caution though.  They are a trifle touchy when protecting their kits.  Best to keep your favorite dog on a leash when watching beavers.  In the water, a beaver has all the advantages and you may have a vet bill if your dog threatens their young.

These beavers, thought are wary of humans so if you want a great experience, sit still where your silhouette is broken up (beside or in front of a tree), talk quietly and whisper to your kids.  They will usually catch the mood and whisper back. Using a flash light will often scare the beavers and they won't come out again for a while. 

Helping the Beavers
Beavers do so much good for the environment and for an individual farm that you may desire to encourage them to create a pond on your farm or in the head waters of your catchment.  The only way you can increase the beaver population is by making new areas attractive to them.  The best way is to truncheoning in a new forest of deciduous trees on the banks of a stream).  Tiny seeps that hardly deserve the name of a stream can be occupied by beavers if the habitat is provided for them.

Dam Building
I just read a web site (which shall remain nameless) that stated that the European beaver Castor fiber unlike the America beaver Castor canadensis does not build dams.  I hate to rain on your parade guys but  European beavers definitely make dams and be thankful that they do.  Almost all the massive benefits that beavers bring to a catchment depend on the fact that they do make dams and thus create ponds. In a new area, beavers tend to build their burrows on the banks of the main river but once these locations are taken up, they will move into the secondary streams where they build dams to make ponds for their safety.  Let's catalog the benefits from beavers.

Water flow regulation
Beavers store water on the land in a number of ways.  This is particularly important in the catchment of the Otter.  The underlying strata is mainly sandstone and water doesn't infiltrate the aquifer quickly, unlike outwash plains such as the ones found East of the Rockie Mountains in the USA or to the East of the Alps in the south island of New Zealand.  In the Otterton, most of the water from high rainfall events shoots down to the sea in a day or two.  Of course, if these are unusually high rainfall events, they cause flooding.  So how do beavers store water.

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Without beaver dams in the catchment, heavy rainfall causes floods downstream

First, of course, are the ponds they create with their dams.  Depending on the topography of the particular area where they build their dams, they can store considerable water.  Beaver dams are somewhat leaky so some water is leaked downstream and water also seeps downward into the underlying strata. holding the water on the land allows time for the water to infiltrate the 'reluctant' aquifer.  

Secondly, the ponds raise the water table in the surrounding land.  Water tables intersect streams at the surface of the water in the stream.  As the water rises in a beaver dam, the surrounding water table rises as well.  In particularly propitious cases, a field which had to be irrigated, now doesn't need it since the field crops can access the underlying water table.  Water then leaks back into the stream, down steam from the beaver dam.
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Much of the water stored by beavers is in the surrounding water table

Thirdly, the dams simply roughen the macro contours along a stream.  Even if all the dams are full when a rainfall event occurs, just having all these dams in place slows down the water flow to the sea.  All these effects lower peak flows and raise low flows.

Check out this rather neat cartoon

And fourthly on a long term basis, beaver ponds catch bed load, suspended sediment, wood chips, scats of various animals, spawned-out salmon and so forth creating a deeper and deeper sponge.  Over time, this water retaining sponge increases.  The effect of the beavers dam to regulate water flow increases over the years.

Incidentally, by catching sediment and bed load, beaver dams extend the life of downstream hydro electric dams and help maintain their capacity.  If a hydro dam becomes filled with sediment, it's water storage capacity decreases and hence its function as an energy storage device.  Also be evening out flow, there are less instances where water has to be wasted over the spill way.  More water is available for generation or irrigation.

Beavers sometimes abandon a site in which case, over time, the dam breaches and the beaver pond becomes a wetland with all the benefits this brings.  Wet lands are rich ecological environments, slow stream flows, catch sediment, hold water and in short, still fulfill many of the beneficial functions of beaver ponds.  Generally, after a while, as the deciduous trees move in from the edge of the wet land, a new colony of beavers will establish themselves in the same area and create a new pond above the wetland.  The deep, water storing sponge grows and grows.

Fora and Fauna
A beaver dam, obviously, gives rise to a location with dependable deep (a few meters) water.  Where before you had a stream, riparian zone and surrounding fields or towns, now you have a new environment.  In addition, you have more dependable stream flows between beaver dams than in streams where there are no beaver dams, with none of the exceedingly low flows which kill fish and other wild life or floods which destroy people's structures.

In the pond, animals such as water voles and muskrat can prosper.  Water birds find shelter from predators in the middle of the pond  and will nest in the reed beds that develop along the margins of a beaver pond.  A whole range of invertebrates, which only prosper in still water can grow and form part of the food chain for larger animals.  Dragon flies, which are excellent predators of flying insects such as mosquitoes and biting flies can lay their eggs and increase their populations..

A detritus cycle develops in the pond based on the bits of cellulose (water log wood chips, leaves, twigs etc) that the pond catches.  This cellulose based detritus feeds a wide variety of fauna. 

A beaver pond becomes the 'go to' area to sit and watch wild life.

Benefits to Salmonids
Here is where the beaver pond really comes into its own.  Many of the salmonids lay their eggs in redds.  These are gravelly areas in a stream.  Factors that decrease the success of hatching include floods which wash out the eggs from the redds,  low water which doesn't provide enough oxygen to the eggs and silting  which smothers the eggs.  Beaver ponds ensure an even  flow of clear water.  This is especially important today with increased silt from farming.  Beaver ponds catch this silt and protect the redds.

Once the eggs have hatched, the tiny salmon are prone to predation from the water and from the air.  The beaver pond provides water which is too deep for wading birds and creates many many niches in the front wall of the dam, in amongst the branches of the lodge and in the  food store of branches.

In areas where the streams freeze in winter, the beaver pond provides water deep enough not to freeze.  Check out this beautiful Youtube video of beavers repairing their lodge in the winter.

Nutrient flow
Most of the time, nutrients flow from the land to the sea.  Beaver dams help reverse this one way flow.  Spent salmon are caught in beaver ponds instead of being washed down to the sea and enrich the pond.  The adult salmon provide the nutrients for their soon-to-hatch young.  Animals which feed in the pond, spread their dung upslope.  Altogether there is a flow of nutrients upstream associated with beaver dams.

Education about beavers
I have heard  fisheries biologists, who should know better, and anglers argue that a beaver dam stops the upstream migration of adult salmon. It is not for nothing that the Atlantic salmon was name Salmo salar .  In Latin it means 'the leaper'.  For a sex crazed Atlantic Salmon that can jump great waterfalls in a single bound and which is heading upstream for its once in a life time act of procreation, a beaver dam is just a little morning warm up.
Image result for atlantic salmon leaping water fall
Atlantic salmon leaping a water fall in a single bound

I think where the confusion arises, is that Salmon will rest in the plunge pool below a beaver dam for a while before continuing upstream.  Sometimes they wait for a wee freshet from a rainfall event to point the way.  Not a bad adaptation when you consider that the stream above the beaver pond will be fuller following a rain.

It is interesting that anglers, who quite correctly have been removing tires, old car bodies and other junk from their streams, also remove fallen trees.  You can see one such case along the Otter.  If you look at the opposite bank as you walk up the stream, you will see the butt of a tree that has been chain sawed off.  Have a look at this web site on 'big wood'. 

Benefits of large wood in streams. Illustration © The Nature Conservancy (Erica Sloniker)
"Big Wood" is of great benefit to salmonids

Pacific Salmon Migration
Incidentally, with the decrease of ice in the Arctic Ocean, Pacific salmon have been found for the first time in streams flowing into the Arctic Ocean and even as far as Greenland.  Since we are not going to mitigate the melting of the Arctic, this migration is bound to continue.  It wouldn't be too surprising to find, some decades hence, some strange salmon swimming upstream in British rivers.

For the purist, this will be anathema.  Of interest, though, are the wide variety of life styles of the Pacific Salmon (also mentioned in the above link).  They range from the pinks and chum which tend to spawn in streams near the mouth of rivers and to swim (at night) down to the ocean as soon as they are hatched.  Sockeye, in contrast will swim down a small stream until they come to a river and then turn upstream and find a lake to reside in for a variable number of years.  Some Sockeye will even begin to treat the lake as an ocean and form a landlocked population.  In which case, on the Pacific coast they are called Kokanee.  I understand that Salmo salar also can form landlocked populations.

Benefits to the Riparian Zone
It is vital for the health of a stream that there is a riparian zone.  Such stream verges shade the water, keeping it cool and of even temperature.  The roots of the growing trees and bushes intercept excess nutrients in the ground water flowing toward the stream from farms.  The trees, bushes and grasses bind the bank together so it doesn't slump and pollute the stream and riparian zones provide not only habitat for wild life but also corridors along which they can migrate.
Image result for riparian zone of river image
A riparian zone is hugely important for the health of a river. 

At first glance, you might suspect that the cutting down of a tree by a beaver is  negative.  The opposite is true.  Virtually all deciduous northern hemisphere trees coppice*.  Not surprising since they evolved with beavers.   A beaver cut tree sends out a plethora of branches.  This has a number of effects.  The tree is now protected from becoming uprooted by a storm and exposing raw earth to the stream.  Light can now reach the under-story so that shrubs and grasses prosper.  Their root masses further stabilize the bank.  The young vegetation is lower where it can be accessed by, for instance, deer and the flush of new vegetation is food and shelter for a variety of animals and birds.  Of course, the new branches supply both food and building material for the beavers.

*Sprout from a stump

When a beaver pushes an unpeeled branch into his dam, it will often sprout and the roots grow down into the dam, greatly strengthening it.  A beaver dam can turn into a hedge.
Image result for beaver dam with trees growing on it image
Vegetation will often grow on a beaver dam, making it stronger

 Often, though, the beaver will first eat the bark before using the branch as building material.  As the beaver pond matures, many forms of vegetation such as Bull Rushes, Lilly Pads, pond weeds and so forth will take up residence in the pond.  More and more, they form the food of the beavers and bark becomes a smaller part of their diet.  It's a pretty neat adaptation.  In a new location, beavers can use their building material for food until the pond vegetation develops.
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Ponds develop a wide variety of vegetation which beavers and other wildlife utilize

Stream Hydrology and Ecology
The river Otter is an ideal location to have the first English introduction of beavers.  It has been well researched in terms of the relation between stream flow and rain fall events, the frequency of flood and low water events, knowledge of the flora and fauna of the stream, especially the trout and salmon and the flora and fauna around the stream.  If our talks with residents is anything to go on, there is a great interest in the re-introduction of this long missing native of Britain.   The Otter is about 32km long with many small feeder streams.  It is surrounded mainly with farm land and has a couple of villages along its length that are periodically flooded.

No major effects of the beavers will be seen until they decide to move into the feeder streams and build dams.  Because the Otter is so well researched, it will be an ideal case study to document the effect of the return of the beavers.

How to get a beaver pond on your farm.
Now is a great time for the people living in the catchment to prepare the areas they want beavers to settle.  It is very easy to establish a food and building supply for beavers and since they are in small numbers to date, there will be time for a wee forest to develop before the beavers discover the location.  Truncheoning is the answer. No need to plant expensive seedlings.

Find an appropriate deciduous tree.  Beavers most appreciate willows but aspens, poplars,  birch and many others will do.  Avoid evergreens.  Sometimes beavers will utilize them but they much prefer deciduous trees.

Fell the chosen tree, cutting it at, say, knee height.  It will sprout and before you know it, you will have the tree back in all its glory.  cut the entire tree into pieces about as long as your fore-arm.  Small twigs can be cut with pruning sheers, large ones with your chain saw.  Large logs, I usually split in four and sharpen the bottom end with an ax.  Wrist diameter pieces, simply sharpen.  Small twigs, leave as they are.  You can leave the cut pieces in the shade for a couple of days and some people recommend doing this.  I have usually used the pieces the same day.

Head for your chosen site with an iron bar and an ax or sledge hammer.  You need a  location in which there is some moisture in the ground. After a good rain is not a bad time to do this so in England that means almost any time.

Pound the larger pieces into the ground.  If the ground is hard, the iron bar can be jammed into the same hole a few times, rotating it around after each thump before pounding in your truncheon.  For the smaller pieces, simply make a hole about a third of the length of the truncheon with the iron bar, drop in the twig and soon you will have  a forest to make the most discriminating beaver happy.

Mitigating beaver damage.
Since we have taken over the habitat of the beavers, we will not be pleased if they cause a road to wash away, flood a favorite field or cut down our fruit tree.  Mind you, before you use the following measures, ask yourself if a flooded field might possibly be of benefit to your farm.  There are many benefits to having a pond and/or wetland on your farm.    However, suppose you have decided that you don't want a field or building flooded.  The answer is simple.  You simply install a beaver deceiver.
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Note the outlet.  It's height determines the water level in the pond

Get a piece of that corrugated flexible black plastic pipe which is long enough to reach into the pond, over the dam with its outlet at the level you want to keep the pond at.  Dig away enough branches during the day to lower the water level to where you consider appropriate.  Lay in the pipe.  Pound in a stake on either side of the pipe on top of the dam.  Nail on a cross piece touching the top of the pipe.  The beavers will repair the damage you have made that night.  then get a piece of wire weld mesh with a hole size of  abut 10cm and a bar diameter of six or eight millimeters.  The mesh they use for cement reinforcing is ideal.  Form this into a cylinder, cut out one or two cross bars at one end and pound it into the bottom of the pond at the intake of the pipe.  If you like, you can put a lid on it and pound it in so that it is completely covered by the water.

Remember, you don't want to siphon all the water out of the dam.  The object is to hold as much water on the land for as long as possible.

If your favorite fruit tree is within about a hundred yards of a beaver colony, put a layer of chain link, wire weld or chicken wire around the trunk.  Problem solved.
A simple way of protecting a special tree.

To finish, lets summarize a few beaver facts

1/  Beavers do not eat fish or any other animal.  The only eat vegetation. As the pond develops, they eat less bark and more water plants.

2/  Beavers. once they start building dams, reduce flood peaks and increase low water flows.

3/  Beavers greatly increase ecological diversity

4/  Beavers enhance salmon and trout populations

5/  Salmon and trout pass upstream and downstream over beaver dams.

6/  Beavers are not responsible for Guardia in streams.  New Zealand doesn't have a single beaver and some of her rivers contain Guardia.

7/  Beavers improve riparian zones by felling trees in the riparian zone.  A felled tree will coppice from the stump and be less vulnerable to wind.  It is good to get sun to the understory of the Riparian zone.

8/  Flooding of some feature such as a dwelling or orchard is easily mitigated with a beaver deceiver.

9/  Damage to a favorite tree is easily mitigated

10/  Beaver dams reduce the concentration of nitrates and phosphates in a stream through the agency of the detritus cycle.

11/  Beaver dams in the catchment of a hydro electric dam increase the amount of electricity the hydro dam can generate, the amount of water that can be used and extend the life of the hydro-electric dam by intercepting bed load and sediment.

The future
The people in the Otter River catchment are very fortunate to be the first place in England to see the return of the beaver.  If we are to believe the scientists, the weather is going to become much more erratic and this doesn't only mean more severe rain fall events.  It also means more protracted periods of drought.

No need for a leap of faith.  We already see some of the results with weather patterns getting frozen in one place instead of moving eastward in a regular progression.  A commonly expressed theory is that it is caused by changes in the jet stream.  Whatever the cause, it depends on  which weather pattern lands on top of you as to whether you experience protracted drought or protracted rain.

In addition, climate zones are moving northward at over a kilometer a year and are likely to take some rather severe lurches northward in the future.   Already, some locations in southern England are defined as sub tropical.

It is a bit of a race against time, whether the beavers can occupy the feeder streams in time to mitigate the effects of climate change which are already beginning to manifest themselves.  At least, the Otter Catchment may be ahead of the game.  The rest of England will be playing catch up but will fortunately have the example of the Otter Catchment to draw on.

When first built, before they have time to settle and before roots  grow down into them, a beaver dam can be washed away by an exceptionally severe flood.  When there are beaver dams  all the way up and down the catchment they protect each other, the flood peaks are reduced and all the dams are likely to survive.  Once well established, a beaver dam is unlikely to be shifted by anything nature can throw at it.

As I mentioned, in all of this, the rest of England is going to be playing catch up.  Hopefully, a really intense research program will document the effects of beaver dams as they become established throughout the Otter catchment.  This will be the body of work that other catchments can point to to convince the uninformed of the benefit of the return of the beaver.

In the end it depends on the people in the Otter catchment.  If they establish favorable habitats for the Beavers and avoid harming them, the beavers will return the favor with interest.

Check out this great poster.