Wind energy - Wind vane

A wind vane is a simple but clever device employed to passively point something in a desired direction relative to the wind.

They work like a flag. Always trailing away from where they are fixed, being carried with the wind.

If we make a rigid flag, it's a wind vane.

If we stick something to the front edge of the wind vane, (where the flagpole is if it was still a flag) we can make that thing face the wind. So for instance if we nailed a sign to the front edge at 90 degrees, the wind would be able to read it.

Rather than a sign, we can stick a wind turbine on to face the wind.

Anything you stick out in the wind wants to act a bit like a wind vane.

Even our windmill blades.

Without the wind vane, the windmill would act like a wind vane itself and would probably loose its sense of direction.

By placing our wind vane at the end of a long pole, we gain a mechanical advantage. Leverage in this case. What that means is a little wind vane at the end of a long stick can overcome the wind's attempt to ruin everything. The little vane at the end of a long stick can stay downwind even though the big windmill wants to be downwind as well.

As long as the entire contraption can rotate freely on the pole that keeps it all up in the air, it will always point the windmill directly into the wind. If the wind changes direction, the windmill rotates and always points the turbine correctly.

I love it when people invent things that use the force they are trying to counter against itself. I realize this is a pretty simple invention, but it was still very clever of whoever thought of it in the first place.

"I wish the wind would stop blowing my windmill out of the wind. I know, I'll just use the wind to point my windmill into the wind."

That's good brain using.

So now we have a better method of making our wind turbine track the wind without having to run outside and re-point our windmills into the wind every time the wind changes direction (the Dutch were a big fan of the running outside method in their early designs). What we need now is a way to point it out of the wind when there is too much of the stuff, without having to run outside. (the Dutch did a lot of running outside to save their windmills from too much wind by furling their windmills.) (actually I think the Dutch windmill operators were live-in like a light house keeper, so they probably didn't go outside so much. They probably just adjusted everything from inside - but I'm pretty sure there was a lot of running around, and constant attention and vigilance involved)

What we need is a method of automatic furling.

Wind energy - Furling

One of the problems with windmills is the wind. Too much of it can turn a DIY windmill rapidly back into the junk from whence it came.

Wind is the enemy of the windmill. Who'd have thought it. When there is too much wind one of several things can happen depending on the application. You can generate too much electricity and over cook your batteries, you can pump too much water and all your cows get bloated or something, you can grind so much flour that you feel a bit like a magician's apprentice with all the bucket work you find yourself having to do, or the whole shebang can just blow over and come crashing down on your neighbour's chicken coop causing an unnecessary spike in insurance premiums.

"But humans have opposable thumbs, the Apollo missions, monorails, trans fats, canned cheese, and Oprah, so surely we have a solution." I hear you exclaim.

And, luckily for me, it seems we do.

The solution is furling.

Generally speaking, "furling" describes turning your windmill away from the wind when the wind gets too strong.

If my memory of my grade 4 project serves me, rather than furling their windmills, historically the Dutch used cloth sails over the wooden frames of their windmill blades. If there was a storm, the sails could be adjusted or in the worst case would just blow out and no damage would be done to the main structure of the windmill. The sails could be adjusted in varying winds to maintain a reasonably constant speed of the grinding wheel or pump.

So, short of the old Dutch option of risking partial destruction, it seems there are a few other methods of furling we might employ to automatically regulate a windmill when it's humans are absent. 

I'll cover them each in detail at some stage. Some of them are particularly clever. 

In fact, I've turned fractionally greener than my regular shade of envy as a result of learning just how clever the simple solutions that these inventors have found really are.

Wind energy - History

I often find the history of an invention or method to be very interesting reading. Not so with the history of wind energy.

The history of wind energy goes something like this....

Someone in Persia (Iran (Islamic Repiblic of Iran)) came up with the idea somewhere around 700 - 800 BCE, but we only have someone else's word for that as there is no record of it anywhere.
It's also claimed someone in Europe came up with it at roughly the same time, but there's no record of that either.
I'd put my money on Persia. They had a stack of good ideas coming out of that area at that time. But who knows. Europe was just gearing up to start burning interesting and particularly intelligent women at the stake, so perhaps the dark ages were brought on by a hundred years or so of property developers getting upset about all the windmills being built. Anyway...

Then the Dutch did a bit of work.

yada yada yada... industrial revolution...

Some farmers used them a lot to pump water, and a bit for generating electricity.

Then a semi-famous actor by the name of Ronald Reagan took some cash that was put aside for R & D on wind energy , and spent it all on ray guns in space or something. I presume that was a good idea.

Then along came the recent past, where we see wind power being a pretty mainstream way of generating lots of nice clean electricity.

This bit's interesting....
According to a recent survey, the present seems to indicate every single person* on earth is taking an intense interest in home made wind energy.

And that's pretty much it for the history of wind.

Did I mention I had a big day yesterday? I'm going back to bed.

*It's possible that there is a fair degree of error in that statistic as my sample size is quite limited, but I'm pretty sure I speak for everyone in this room when I say "Everyone here is actively involved in wind energy."

Wind energy - Betz' Law

Graphic interpretation of Betz' law
The energy in wind is a lot like the hot air in drivers. If a bit that's up the front runs out of energy and stops, all the ones at the back just plough into the back of the stopped one at the front, get angry, uncooperative, and everyone gets a lap full of coffee. Nobody's going anywhere. Wind doesn't get coffee stains - that would just be silly - but wind cant go very far when there's some uncooperative,  stationary wind up the front with no energy. So we find ourselves faced with some kind of limit.

If you take all the energy out of wind you cant get any energy out of the next bit, because in no time, the whole place is gummed up with stationary wind. So we find ourselves forced to slightly less greed, and only take a percentage.

We are forced to take less that 59%. Albert Betz did some apparently good work in finding this theoretical maximum limit for us. I say apparently, because aside from a stack of numbers and letters, his equations include things like triangles and a very great many dots where previously I thought such dots never went. In short, to me they mean nothing. Besides, my keyboard doesn't have a triangle key, so we are just going to have to take his word for it. Anyway, in reality we cant get 59% , because of all kinds of inefficiencies, and my frustrating lack of an infinitely thin rotor in my pile of junk. The best part is we really don't need 100% efficiency because there is plenty more wind where that came from, and the stuff is free.

 Hmm, perhaps Nobel simply didn't like triangles.

Wind energy - Blades

It turns out, there is a stack of energy in the wind. In fact the more I research, the more I see it that way. I'm starting to get some kind of grip on this energy stuff. I'll try to explain what I've understood so far.

Water pumping windmill
Just looking at the traditional windmill for now, (traditional to me) the one that looks like a fan, we see there are a stack of different blade shapes, and some seem to have more blades than others. Some seem to be always used for pumping water, and others seem to be always used for generating electricity. In keeping with 120 things in 20 years tradition, I'll start an explanation of wind energy by talking about cogs.

Connect two different sized gears together. Choose two cogs so that when the small one rotates 100 times, the large one rotates only once. Now give the gears some power by turning them. The same amount of power exists in the big and small gears, but in the small gear, its spread out over 100 turns. This means that you can slow it down by resting a feather on it. It has no grunt. Try the same feather trick with the large gear, and your large gear wont care a bit. 

If you put a set of wheels on the axle of the small gear you will zoom along until you get to a steep hill, or a feather.

If you put a set of wheels on the axle of the large gear, you will drive slowly through a pillow factory with ease.

Having just described this, for the first time in my life I suspect I might be leaning toward some vague understanding of "torque" that I didn't have when I started this post. I think torque might be rotational grunt, where power is what the engine has. If this is true, you can express an engine's power as more grunt or more speed while keeping the same power (the engine). That must be it. Or not. But for now, I'm sticking to "grunt", so now might be a good time to edit your dictionaries and engineering manuals.

A windmill's power comes from the wind. If the wind is fast we get more power. Now, picture a string of air 100 metres long. That's called a string of air. Now move it at 100 kph. That's called wind.

If we slice that 100 metre string of wind 100 times we get 1% of it's power in each slice.
If we slice that 100 metre string of wind 10 times we get 10% of its power in each slice.
That's simple enough.
If we have a 10 blade windmill, it makes 10 slices every time it does one revolution. That means it will make 10 revolutions as that 100 metre string of wind blows past.
If we have a 100 blade windmill, it will make 100 slices for each revolution. That means it will make one revolution as that 100 metre string of wind blows past.

The same amount of power is in that 100 metre string of wind, but we can harvest it in such a way that suits any combination of grunt and speed that we might need for our application.

The 10 blade windmill spins 10 times with stacks of speed, and the 100 blade windmill turns only once, but with more grunt.

It turns out that lifting water from a well requires lots of force, so we use windmills that have a lot of blades, and generating electricity requires a lot of speed, so we tend to use windmills with fewer blades in power generation.

A 100 metre string of air doesn't really get you 100 slices. Actually for all I know it might. But it probably doesn't. I made those numbers up to make the calculations easy to see, but it all works pretty much the way I described.

So anyway, that's the story of where babies come from.

Wind energy

There's a lot of wind about of late. It's got me thinking.

Quite a few years ago, I was talking to my two year old friend Sarah, when the subject turned to wind. I asked her where it came from. She looked at me as if I was a bit of an idiot, but then, to my delight, she patiently explained it to me.

It turns out trees make it by waving from side to side.

Obvious really.

Other than a bit of sailing experience, and a decent understanding of where the stuff comes from thanks to Sarah, I don't know much else about wind. I'm about to rectify that. I'm going to learn how to make a windmill. And then, once it's made, I'm going to do something with all that wind energy I collect. There are a few things that spring to mind that I might do with some wind power.

  • Grinding flour is one, but I tend to get someone else to pre-grind my flour. 
  • Pumping water. I do a lot of that at the moment in aquaponics, so that could be useful. 
  • Or even generating electricity. I really need to learn about the stuff, so windmills might be a good introduction to electricity. 

Whatever I end up doing with my windmill, it should be an interesting learning experience.

The weather has been too rainy and windy to put much of a dent in all the things I need to do on the new aquaponics system, so I'm reading everything I can find that has anything to do with wind energy.

Handmade fishing lures - Super lightweight lure

I found myself testing some problem solving approaches, and came up with this as a way of making a hardbody fly, or ultralight lure.

We have an introduced pest species called Redfin Perch in Australia. It's not as bad as some introduced species, but it still displaces native fish from their natural habitat. Because of this it's illegal to return them to the water, which is fine by me because they are not bad to eat.

From looking at the contents of their stomachs, I've discovered that they tend to eat very small insects that either live under water, or land on the water from time to time. At least they do here. When you catch them in waterways like the Murray river, they tend to be full of small yabbies and glass shrimp. When fish are eating tiny things, they tend to get a bit spooked when you lob great big lures into their river. I figured what I needed was a tiny, lightweight hard body lure, with a tight swimming action to look like a downed flying insect that's now swimming.

One of the heaviest components of the lures I've been making, is the wire harness. All those wire eyelets for tow points and hook hang points end up weighing more than the rest of the lure. Lightweight means the harness had to go. Also the rear hooks had to go. In fact, there was no reason to have more than a single hook rather than a pair of trebles.

I started By stripping some very thin electronics wire out of it's insulation, leaving me with a very thin tube.

Next I make a tiny lure, and thread the thin insulation tube through a hole drilled first from the front, then from the underside until it meets the first hole.

Glue bib, lure body and tube in place with a drop of superglue.

I hold it all together with Blutak while I'm gluing.

Paint it (or not), then when it's dry, trim the tube flush with the lure at the belly, and as long as needs be to get a good towpoint at the front.

Then simply thread your line directly through the front, and attach a hook where it comes out underneath.

I use them un-painted and not waterproofed in any way. I tend to lose a few to overhanging trees, and would prefer they just rust away and rot rather than hanging around for too long.
I'm using these on the River Torrens where it's only 4 or 5 metres wide at the most, so there are no issues with casting. On a windless day, I'm only just making it to the far side of the bank with a relaxed cast on 1.8 kg line. And at least 2 of those 4 or 5 metres are covered by the length of my rod and my arm. There's no casting records about to be broken with these little lures, but in the right spot at the right time, they work a treat. The redfin only measure 20 cm or so but I've seen bigger fish eat smaller things so they might be worth trying on bigger fish if casting to them isn't an issue.

The one pictured here weighs a little over one gram, and only makes a tiny splash when it hits the water. I'm sight fishing to hiding redfin, and they can be very timid or crazy brave. When they are timid, using these lures I'm able to cast a lot more often at the same spot before they get spooked. With a normal hard body lure, I might only get 2 or 3 casts before they wise up, with a spinner, that might be only 1 or 2 casts.

It might also be interesting to try them on a fly line.

[edit from the future - This post on painting lures, "how to get the most out of your printer", might interest anyone who found this post useful ]

Aquaponics - Pump-less cycling Success!

Sometimes, I know things like cycling a pile of gravel should work, but I'm still surprised when they actually do.

After shovelling 3/4 of the gravel into my grow bed, I got lazy and went to bed. But I thought I'd try getting a head start to cycling up my system as gravel in a grow bed, and a pile of gravel on the ground. 

It was about to rain, so I figured it was a good time to add some fish emulsion to the gravel. When I last wrote about pump-less cycling, I promised I'd let you know if it worked.

It worked!

My recent test showed some nitrites.

The sample pictured was taken from rain runoff, at the standpipe in my new growbed.

To make sure I wasn't getting the nitrites from the bottle of fish emulsion, I tested some fresh water with fish emulsion added. 

ammonia 2.0
nitrite 0.0
nitrate 0.0

What this means is, there were no nitrites introduced directly from the bottle of fish emulsion. What that means is that my pump-less, sump-less, no fishtanked system is cycling, because the nitrites must have come from the bacteria in my new system.

No great surprise really, but still interesting.

It's actually not that important for me to cycle my system, because I will be adding 100 litres of mature media from my test system. That 100 litres of media is currently coping with my eleven silver perch, so in the new system, it should continue to cope. As long as I transfer it in such a way as to keep it wet at all times, my nitrifying bacteria colony should find its new home welcoming. I'm told I should bury my old mature media from the small test system at about half way down into the new gravel media for best results.

Aquaponics - High density marron farm idea

I've had a few more thoughts on a high density marron farm, and they seemed to have coagulated into something that looks a little like this.

Side view - High density  marron farm idea 

The water and solid fish waste would flow from the fishtank into a flow splitter made from an 8 inch PVC pipe connected at right angles. The flow splitter would then be connected to a number of 8 inch PVC pipes that would slowly take the flow to the growbed.

Each PVC pipe would contain a number of different baskets that could move freely along the PVC pipes.

Each basket would hold one marron. The largest marron would be those closest to the fish tank, and these would get first bite at solid fish waste, and uneaten food. As the feed and solid waste moves to the right, the other, progressively smaller marron get a chance at it. Mature marron would be harvested from the end closest to the fishtank, and new small marron would be added to the system at the growbed end. Each marron would be in a separate basket to prevent fighting.

The water would enter, and move through the system via gaps at the bottom of the baskets. To maintain water in the pipes, the water would exit the pipes at the top.

Top down view - High density marron farm idea

Seen here from the top, we see the flow rate from the fish tank would be very slow because of the large diameter of all the PVC pipes. This would give the marron several chances to catch passing food. The total flow through the system is the same as it would be without the marron farm, but because it's spread over such large pipes, the flow slows.

The length of the marron farm pipes would depend on how many marron your system could support.

Using this or a similar system it should be possible to grow marron (or whatever underwater walking things are called in your part of the world), in an aquaponics system without all the cannibalism that can come with underwater walking thing farming. This marron farm would be placed in the following order of flow...

  •  fish tank
  •  marron farm
  •  swirl filter
  •  grow bed

Small marron might be kept in an aquarium, and only the largest of the batch might be added to the farm each week. Grading out only the biggest marron might prove difficult so I might have to come up with a way to trap the biggest and let the others through unhindered.

Or something.

I'm not sure if this is the solution for me. It's just an idea that was rattling around in my head, so it had to come out.

Aquaponics - Duckweed growth rate

I hadn't noticed my duckweed growing, because I tend not to notice such things. But when you compare two photos taken a week apart, it becomes difficult for even the most stubborn unobserver to ignore.

Duckweed grows really fast.

This is what it looked like on the day I bought it.

And this is what it looked like a week later. And I'd given some to the fish!

I only noticed it a few days ago when I was sorting photos.

It does grow only in two dimensions, but it is still amazing.

Duckweed is known for choking river systems, but it's only because the water is far too nutrient rich from fertilizer runoff and other intensive farming and industry. The single leaf with the insect on it still looks the same after a week. I was expecting to be able to show it dividing, but its growth is slow, probably because the water it's in isn't saturated with nutrient.

It's interesting to note the small root system the photo at the top of this post shows. I couldn't see those roots without the aid of the camera. I thought each leaf had a larger white root, but it looks like there are many on each section that will one day become a plant on its own, although its possible that those fine green roots are actually algae or some other type of bio string.

Aquaponics - Duckweed auto feeder

I've had an idea.

Duckweed grows at an amazing rate. It also seems to spread out to take up the entire surface available to it. This appears to be a function of surface tension. But I may well be wrong so don't quote me on that. In fact, don't quote me on anything.

Because of the way duckweed spreads out over it's available surface, it should be possible to use that, and various other handy attributes of the universe, to make an Aquaponics duckweed auto feeder.

Here's what the original plan looked like.

The pump for my new aquaponics system will be on a timer, and will run for around 10-15 minutes each hour. When it runs, a small amount could be diverted to the duckweed auto feeder. The diverted stream could be applied to a PVC pipe  in such a way as to divide the floating duckweed. If required, the stream could be shaped so it spreads across the width of the PVC, and perhaps points away from the standpipe. If the stream is set to spray across the top of the water, it will keep the majority of the duckweed away from the standpipe, but still allow the water to pass under the stream,through the standpipe and into the fish tank.

Here's the animation that might make it understandable.

Aquaponics - top down view of duckweed auto feeder 

  • When the water flows in from the sump pump, a small amount of duckweed is separated from the majority, so that it moves toward the standpipe (to the left) and the rest is kept away to the right.
  • The water overflows into the standpipe, into the fish tank.
  • The overflowing water takes a "dose" of duckweed with it to feed the fish.
  • The size of the dose can be determined by the placement of the water inflow. Moving the inflow further to the right would increase the duckweed dose, to left would decrease it.
  • Because the duckweed spreads out to occupy the available space, the dose would be a percentage of what remained rather than a set amount. This means you should never run out of duckweed. If there isn't very much in the system, only a small amount would be delivered.
  • The duckweed will grow faster in summer when the silver perch want more feed, and it will grow slower in winter when the fish are not so hungry. The faster it grows the more the system will deliver on each pump cycle.
  • If required, a thinner PVC pipe would allow for better fine tuning to allow a smaller amount of duckweed to be delivered each time.
Once it's set up, it should largely regulate itself.

My plan is to make a large bed of water to grow duck weed in, using goat dung for nutrient, and create a duckweed auto feeder connected to my fish tank, that I can scoop some duckweed into every few weeks.

Here's a side view animation 

Aquaponics - Split system

A rule of thumb ratio to stick to is 2 grow bed : 1 fish tank. This allows a big enough population of nitrifying bacteria to process the maximum safe population of fish.

The maximum safe limit of fish population is 3 kg for every 100 litres of water. since a litre of water weighs 1kg, we can say that 3 % of the fish tank's weight can be made up of fish. That's a lot of fish for a cubic meter of space.

The issue with the 2:1 ratio of grow bed to fish tank, is that the grow bed takes a very large percentage of the fish's water. I'd like to grow some marron as well as all these fish, so I'll want even more grow bed. Even more grow bed means my fish will be spending some of their day walking around on dry land.

Fish hate dry land.

One possible solution to this is to add some extra grow beds down at the sump level. My aquaponics space is on a flattened area of sloping ground, so its easy for me to add grow beds down the hill a bit at the sump level. This means the grow beds can act as extra sump capacity rather than being a drain on sump capacity.

When I add my marron farm, I intend to add some blue barrels as large planter pots for a few fruit trees. I'd love to grow a lime, and some blueberries, and perhaps raspberries or grapes.

My description is lacking, but luckily I spent all morning making an animation to demonstrate what I mean.

  • The pump is on a timer and runs for 10-15 minutes per hour.
  • Water is pumped from the sump up to the fish tank.
  • We make the water exit the fish tank from the centre at the bottom because with the pump creating a bit of a whirl pool, that's where all the solid fish waste will gather.
  • The water and solids from the fish tank enter the swirl filter. 
  • The swirl filter has an inlet port half way up and and outlet at the top so the solids sink to the bottom and are left behind. In the event of some kind of "over nutrient emergency", I'll be able to remove the days solids to lessen the load on the system. If all is going well, the solids in the swirls filter will be chewed up by a few cups of shell grit until they are small enough, and light enough to float out into the growbed. This should help distribute the solids, allowing them to easily flow to all areas of the growbed.
  • As soon as the growbed starts to fill, it also starts to empty via hole in the base of the standpipe, but the inflow rate is higher than the outflow rate so the growbed's water level rises.
  • Once filled, the open top of the standpipe allows water to flow free back to the lower level to prevent overflow.
  • The pump runs for a while longer. The length of time the pump runs for is determined be the need to turnover approximately one fishtank of water each hour. This helps oxygenate the water, and allows the bacteria to get a look at the ammonia, and nitrites.
  • The pump shuts off.
  • The grow bed continues to drain over the next 40 minutes or so.
  • When the grow bed is full, the planters are drained. When the planters are full, the growbed is drained. This way we introduce extra growbeds into the system without needing a larger sump.
  • Water flows freely between the planters, and the sump. 
  • When evaporation or plant use drops the water below the trigger level of the float valve, water is added from my concrete rainwater tank. My concrete tank water has no chlorine so it can be added directly. It also has a similar pH to my aquaponics system. If you use mains water, you need to have your water sit for a couple of days in the sun to turn the chlorine into something less harmful to fish. [see comments]
  • The cycle repeats.

Aquaponics - IBC's

IBC's or intermediate bulk containers are how humans shuffle bulk liquids around the world. IBC's are the container of choice when a blue barrel simply isn't big enough.

I used blue barrels in my first test system, but my new system calls for recycling on a far grander scale.

I finally managed to organize 2 IBC's, a car with a towbar, and a trailer, all on the same day, at the same time.

I also organized for it to be a spectacular day.

My IBC's originally had honey in them. They are clean, made of food grade plastic, and a little bigger than a lot of other IBC's I've seen.

Interestingly, they also have a heater in them. It turns out it's not at all uncommon for IBC's to have heaters to allow stuff like honey to flow on cold days. It seems amazing to me that we make single use containers with a plug hanging out of them. The few hours I spent in the back alleys of our port district was a bit of an eye opener in terms of just how much waste there is in industry and transport.

The "food metres" involved with aquaponics coupled with some recycling will ease my troubled head a bit.

But not much.

One IBC will be used as a fish tank and the other as a sump in my new CHIFT PIST aquaponics system.

Aquaponics - Duckweed


I finally got hold of some. I've been looking around for it for ages, but all the plant stores stock a plant that isn't really duckweed. Every single nursery I've been to has assured me over the phone that they stock the real deal, but have all turned out to have something else.

I guess I should mention that the reason I wanted the stuff is because fish eat it. Its a great way to get rid of excess nutrient, and is also a useful feed because it floats so doesn't get sucked into the pump before the fish get a chance to eat it.

It looks like this. At least I hope it does. All plants look the same to me.

Duckweed has some claim to fame. I'm told it produces the smallest flower. But I wasn't told it makes three of them, so I guess there is good reason to doubt it's record holding status as well.

Who knows.

I have duckweed.

As far as I can tell duckweed normally reproduces asexually by dividing into two leaves. If you look at the picture, you can see some leaves almost look ready to divide. Many of the leaves have two roots extending ten or fifteen millimetres into the water. I'm guessing when the leaf decides into two, each half gets a root. I'm told that it also does the pollination thing from time to time, but who knows.

I have duckweed!

I put some into a large container with some fish emulsion as fertilizer. After a day or two I noticed an oil slick, so I  added an air stone attached to a small fish tank air pump. The slick cleared up within a few hours, and the duckweed took on a healthier shade of bright green. I know there isn't a lot of science in that, but I'm guessing duckweed needs oxygenated water. I was hoping to just keep it in a container of water with a large surface area, throw in some goat dung, and leave it to it's own devices, but I don't think it's going to be as simple as that.

The plan is to use the original planned growbed with pvc edge capping for a duckweed plantation. The growbed was too easily scratched to use with gravel in it, but filled with only water and duckweed, it should be fine.

I kept it for five days before giving it to them because I was concerned the pond it came from could have had some diseased or parasite infested fish.

I only know a small amount about one fish ailment other than poison plants, and that is a parasite called Ich. Ich is a fish parasite that can't live away from fish for more than three days, so at least my five days should prevent it from being an issue.

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