Sunday, 12 March 2017

Designing variable rate micro-hydroelectic plant

Generating power using water is nothing new. Find a location where water can be channelled from a high location, through a wheel, (or turbine) and released at a lower location. The difference between the high location and the exit from the wheel is known as the head, (of water). This was used even before the industrial revolution, to turn wheels that performed work, (ground grain into flour for example.)
The industrial revolution used water to perform more and more tasks. The problem was that you can't take a river with you. This is where coal empowered the steam engine. First used to drive pumps and then steam engines were mounted on rails for locomotion. More and more ideas collided with both problems and everyday tasks. The industrial revolution tried to make life easier, (though it also created inner-city slums - a problem that we still have not solved.)

Out of the industrial revolution came the industrial age. In the years from 1930 to 2030 it was still fossil fuels, (oil and coal) that were used to supply the energy needs of the growing industrialised countries. Yes we still used hydro and we had fission but for the most part it is coal and oil that cooked our food  and powers the television, (and certainly powers transportation of resources into the cities where an insect-colony level of density is observed.)

 So what is the problem? The problem is that how ever much oil there is hidden under Greenland by the year 2000 half of the oil and coal has already been consumed, (lets just presume this is true) and we can do many things with modern technology, but we can't make more oil or coal and we still can't capture the suns energy as efficiently as plants do.

(This is just a visual guide, to help my explanation.)

  So I grew up next to a small stream and love mechanical devices. The idea that water can turn a wheel that can produce electricity still makes me smile. It seems as natural and as magical as gravity, (and sometimes just as frustrating.) 
 The two problems that my location has from a hydroelectric point of view are no head, (which is why I mentioned it at the start) and a massively variable flow rate. So why is this a problem? If you are not scared off by terms like volts and amps then you can probably let me run with the idea that the head is equivalent to ampere-hours and the flow rate is equivalent to the watts. ( For this note we just need to think: amps * volts = watts ). So with this undershot design we are dependent on the flow rate.

The devices that we use today in our homes use AC current and like to have a fixed voltage, (110-240 volts depending on the country) and require 1-20 Amps, (I'm talking household appliances like a toaster or a microwave oven.)
So it should be clear why large scale hydroelectric systems seem to always have a large lake with some means of flow control. This is because the best locations for the generation have been selected, (usually locations where it is easier to build a wall to hold as much water back as possible. In the past whole villages have been moved or flooded because they occupied such locations, (Tignes, France.)
 Also hydroelectic systems do not like creating elecriticy that is not being used, (things tend to melt, in a bad way.)

I don't want to move house, and I don't have the money to either build a massive pipeline to create head, or a really long power-cable to get the electricity back from the best location on the stream. If we are going to design useful systems they are going to have to fit in with the existing landscape and be as unobtrusive as possible. (My theiroy was that if this works they could be added to any small stream, and added many times to the same stream.)

So the variable rate problem is not too hard to solve: bicycle gears - simply employ a gear system that engages higher gear ratios between the turbine and the generator as the turbine velocity increases. But that is only half of the story. If you inspect my proposed site the water level can vary by over a meter, (from zero in summer.) The stream is full of a range of limestone rocks/pebbles and every the occasional boulder. The stream is insized and creating a water chase is beyond the scope of this project. The solution that I came up with uses two vertical PVC drainage pipes with empty two liter polyethylene terephthalate drinks bottles inside. 
The bottles act as floats upon which the rig, (turbine and generator on a frame) can balance. The vertical pipes are resessed into the sides of the stream, (it is less than two meters wide) with a vertical slot cut into the face of each. As the water level rises the bottles float up and lift the rig. This means that as the flow rate increases the contraption is lifted clear of the rocks that are moving along the bottom. This protects the blades of the turbine, and though it sacrifices some of the energy of the stream, we are still in contact with the part of the flow with the least friction from the sides and bed of the stream. This all looked good when I sketched it up in freeCAD but with some rough calculations the rig was going to be too heavy. The first amendment was easy: a cable connected inside the PVC verticals to the rig. This ran to the top of the verticals, over a pully and down the outside to a counterweight. This counterweight ended up being a steel sleeve that wrapped round most of the vertical, (this kept is tidy and accessible to raise the rig for maintenance. Originally the blades of the turbine were made from plastic guttering, but to experiment with shape we had a set that we made from wood. This changes the weight of the rig, but with the location of the counterweight it was easy to tack on pieces of lead to correct the required mass.
  Then winter came. The torrent was huge, and fast - lots of lovely power ready to be collected. The second problem with the design became apparent: The buoyancy of the bottles and the turbulence of the surface meant that the rig was being bounced up and down. We could try and increase the friction between the inner surface of the PVC vertical and the bottles, but friction is something that we have been fighting to reduce, (more power less wear.) Then I remembered by sailing days and the concept of a sea-anchor. We all know anchors are heavy things connected via a rope or chain to a ship. The anchor rest on the bottom and provides a fixed connection. What happens when the water is too deep? A sea-anchor is like an under-water parachute. To begin with I tied a string to each of the corners of a pocket-hankerchief and tied the four strings to the bottle. This hankerchief-anchor rested under the bottle and in the water. When the level of the water rapidly increased this latest addition stabalised the assent. This was a good prototype, but only solved the "bu" not the "mp". Running with the idea that if it worked in one direction then it should work in the other I added another pully to the bottom of the vertical supports and ran a new line from the bottom of the counter-weight, over this new pully and out to another hankerchief-anchor shock-absorber, (by now the HASA was made of rip-stop nylon.)

Now I just have to finish the automatic gearing and measure the useful current.

p.s. Yes the turbine axel is connected to bearings that are attached to the frame of the rig. These are not shown in the above image. Also missing is the counter-weight contraption, (because that would give away the story.)

Thursday, 23 February 2017

You won't believe how surprised computer scientists were at these results!!

President of the United states of America FAILS the Turing Test!!!

 Last night the well respected team of scientists lead by Professor Et Al published their latest findings in Nature You might not know that all world leaders are routinely screened to pre-emptively check for dementia, (no one should want a clinically insane person with their metaphorical finger on the nuclear button). One of the regular test is a tried and tested Turing Test created by the eminent Cambridge scientist Alan Turing.

 The shocking truth is that Donald Trump failed his latest Turing Test! This is the first time in history that any adult has failed to pass this test.

The elegance off these battery of tests is that each and every country can each independently run them to ensure that diplomatic discourse has a chance to maintain trade and continue our inevitable progress towards world peace.

The physical tests, such as blood tests to check for Treponema pallidum and other potentially mentally debilitating infections have to be administered locally by their native country. These results can be shared via covert diplomatic channels to quietly maintain stability.

Thankfully,  where there is animosity between the countries there is a huge collection of tests that can be applied. Some of these are statistical analysis of
verbal and written language. Thankfully, with the advent of Twitter these tests can be performed in real-time 24/7 to provide continuous results. So far it has been all clear. There have been a few close calls but yesterday was the first conclusive failure.

What does this mean for his country? There isn't currently an established channel of care to safely inform the president of his failure, which leaves all of Washington wondering how to fix this major problem.

[0] Yes this is a click-bate parody [joke/]

Wednesday, 8 June 2016

Best pen ever

You should be thankful that this blog is not in my handwriting. I've never liked my writing; It damages my artistic enjoyment of the world and scratches against my sense of beauty.  At the same time it appals me like any other revolting thing that may emanate from my corpse.

That said, from time to time I do scrawl of sheets of dead tree and when I do I want the experience to be as painless as possible.

I feel that I am a long way off from being an enthusiast, like some people, but when I find something that I like, I want to share it, (and be able to remember it, hence this entry.)

There have been three good pens in my life worth mentioning and the first, (maybe controversially) is the Pentel P205.  For those of you watching in colour, it looks like:
Pentel P205 propelling pencil

 Why might this be a shock? Because it is, <noise like="Dun Dan Duuuun"/> a pencil. The P205, (like its yellow sister P209 and blue P207, and brown P203), is a propelling pencil. The P205 takes 0.5 mm leads, (P209 takes, you guessed it 0.9 mm).

I've had three of the P205 so far, and two of them are still working, (even after years and years of use.)
(I had a P209 but I leant it to someone at school and forgot to get it back.)
Some would argue that the P205 is too light, but for me that is part of the appeal - it feels sturdy enough without needless weight. The pocket-clip is detachable, (if you need to?)

The next pen worth mentioning was a gift from a bandwidth supplier, ( It came in a nice box that looked like:

cross box

and the pen itself looked like:

Cross ATX Matte Ballpoint Pen

The Cross ATX Ballpoint pen, (not to be confused with the water-based roller-ball version, which has a cap that comes off like the fountain pen in this range), twists to retract and extend the point of the cartridge.

This one feels expensively heavy in the hand, (even though it is one of the cheapest of the Cross pens.) I really liked how it wrote, but clearly not enough... because I left it somewhere in Cambridge.
I plan to get another of these and having inspected a few reviews I would go for the same colour and the matte finish.

That leads me to the latest entry and a short story. I found a pen. I liked it. It felt like the best of the previous two, (light, wrote well, didn't feel excessively cheap, but I didn't mind lending it to someone.) I planned to make a note about this pen, using said pen, so that I would be able to get another one once I lost this one... which I promptly did. All I could remember was that it was black, wrote well and had a metal pocket clip. I searched the house a few times and then gave up. The plan was to let my unconscious remember where it was and let me know. That was 2009. Today, the fourth day of June 2012 I found it, and what is more I found out why I had missed it in my previous searches. The metal pocket clip had broken off, hiding like a two leafed clover, in with a jar of other pens. The pen that I'm talking about is the Pilot V-ball 0.5 and looks like:
Pilot V-Ball 0.5

Now if you have tried the 0.7, (which is, on some websites, sold as the 0.5) you may, like me think that this is a smudgy pen that gushes too much ink. In my hunt I found a few of the 0.7 and had surges of hope, (they were black and had a metal pocket-clip) only to be disappointed as they vomited their tar onto the page. Then this evening I noticed a black pen from which the pocket-clip had been removed... The clouds parted as divine intervention struck my brain with imagination, expectation and understanding. To be precise the barcode on this pen is: 4902505085406 (yes, I really don't want to lose this pen again - and when I say "this pen" I mean make-n-model.)

As I do very little writing, (some would argue that I do none at all and that my scrawls don't count), I would be interested in any recommendations from people that have tried one or more of these three and then found something even better.


p.s. I'll probably mention this in a few posts, but to add the images for this post I have to thank $The_Internet and openssl. The images are created from jpegs with the command:

openssl base64 -in image.jpg -out image.base64

and then added to the HTML with <img alt="What this is" src="data:image/jpg;base64,
[Paste in the data from the image.base64 file here]  "/>

Obviously, if you are using PNG then change the src to data:image/pgn;base64,

Tuesday, 5 April 2016

Babies first words

I was pleasantly surprised to be asked by a friends child, "which language should I learn?" From the context it was clear that they meant computer language. I regularly write in five, (though which five changes with time context and application, and that's not including things like CSS,) so my first reaction was to resist recommending the language de jour, (either mine, which happens to be C++, or the a-la-mode python.)
  I asked what operating system they had regular access to and found out that they had windows. One of the most under rated, and most abused languages is ECMAscript. I remember, (I'm that old) waaay back when Microsoft created the only tolerable operating system, XP I had to create some scripts to automate a project for a client and I ended up using JScript.

So I installed notepad++ and naturally wrote:

wscript.echo("Hello World");

Saved it as hw.js and told them to double click it.... (My kingdom for a horseshoe nail.)  My "cool" melted away with a jarring "gank" alert noise. I then took far too long to remember/realise why.

Some part of my brain had automatically discarded the solution because, "everyone knows that windows is case insensitive."

WScript.echo("Windows JScript IS case sensitive: wscript.echo\n Error: 'wscript' is undefined\n Code: 800A1391\n Source: Microsoft JScript runtime error\n I feel like my whole life is a lie; unix = case-sensitive (it cares), microsoft = (case) insensitive. Jay script? more like BS cript.");

// JScript is NOT windows filesystem.

Sunday, 31 January 2016

[windows] NAS re-connect fail

TL;DR: Control Panel > Credential Manager
On the right hand side "Add a Windows Credential".

I've just been repairing someone's dual-boot Debian/Windows 8 laptop, (obviously it was the Windows that had the problem.) When I boot the, (frankly cheap, but brand new) laptop into Linux everything that I request seems to happen instantly, or much faster than Windows. [0] They have a NAS and each time they reboot into Window they had to re-enter their username and password. (The NAS partitions mount automatically under Linux. ) So I checked that the NAS supported SAMBA, (it does) and did some other tests. I created a test user on the NAS and that worked, (would reconnect by itself after reboot.) Eventually I realised the problem, (I had to get into the cult mindset of Microsoft.)

The user had the same username to log into windows as they do for the NAS, so the Windows operating system defaults to the local details. This is despite the re-connect challenge window having a "Remember these details" box - which Windows arogantly and presumptuously ignores, and uses the local system details... which fail because the user is well trained enough to not use the same passphrase for everything.

The details that most helped me crack this problem was actually on a microsoft site. My thanks to maximus006dflw:

MA maximus006dflw replied on
Use credential manager in Windows 7 to remember the username and password for your NAS Drive if it doesnt remember it automatically.
Go to Start / Control Panel / User Accounts and Family Safety / Credential Manager
On the right hand side, right below where it says "Windows Credentials" Select "Add a Windows Credential".
Enter your NAS' Server name in the first box.
User Name in the second box and your password for the server in the third box.

[0] For example, opening a new folder on Windows takes 1 to 10 seconds, depending on how its feeling. On Linux it seems to happen before I've finished pressing the W+f chord.

Thursday, 28 January 2016

Things to do with your hands

The first type of shorthand that I tried to learn was one of the Pitman. Since then I've found that I prefer the Gregg/Thomas/Boyd/Gabelsberger/Groote flowing types.

If you are interested in such a thing then I would suggest learning Hangul and then looking at Arabic script before creating your own system.  (Note Devanagari digits!)

SI units and scientific notation help to keep numbers short.

If you want to lengthen a vowel from win to wine then just add an ee. [wat?]

The problem is that stenography has been shown to be much faster than any popular keyboard, (such as Qwerty). The advantage of, (light line) shorthand is that a any writing surface that has a flowing system of writing, (pencil on paper, chalk on slate, finger in the sand) are all possible without specialised equipment.

That is where Plover is so interesting.

oh and Learn Cued Speech. It makes you a superhero.

About this blog

Sort of a test blog... until it isn't