Selecting bigger alder seeds by their falling speed in air

You can eat alder seeds? I didn't know that.

How big are they anyway? How heavy?

-- Peter Fairbrother

Yes the FPS system if I remember rightly (Foot-Poundal-Second), I started with the symbol "a" for acceleration which changed to "f" some years after. Don

Well that answers the question about the Chicken Tikka....................

John S.

No war or criticism intended Michael. Fortunately this newsgroup is open to discussion and even argument without getting offensive, though it does mean that threads often drift off topic.

Have you considered a centrifugal separator for your seeds?

an industrial machine, but it shows the concept.If you could make something suitable it would probably be more compact than the machine you envisage, though somewhat more expensive.

Cliff.

It depends on your newsreader, but the normal way is to use the caret ^ character to denote a superscript. So it's s ^ 2 without the spaces, s^2.

Some newsreaders also allow the use of the underscore _ to denote subscripts, but not many.

Both of these conventions were popularised by TeX, though the caret was used earlier in Algol.

How nerdy that I know that!

-- Peter Fairbrother

Forgot to mention using a round tube would probably give better cutoff than a square one.

-- Peter Fairbrother

Thank you very much for this. In my scrap box I find I have a round tube plastic tube diameter 2.5 cms and length 30 cms, which is quite wide enough for cones to fall through. I am hope to keep out clusters of cones but there will always be detached cones.

On full volts the fan (Sunon KDE1208PKV, RS Components 544-1018, a computer cooling fan) can pull seeds right through (and so to waste) but can only just lift full-size seeds through a hole of this diameter, obviously there's a lot of drag. So I want to ease the entry (and start uniform flow across the tube as soon as possible) by putting a cone around the entry like this :-

| | | | | | | | / \   / \ / \ / \

What thoughts?

Michael Bell

Thank you for this link.

It has to be a portable machine, powered by a little 12 volt lead-acid battery. I want to be able to do a full day over ground which will not always be even

Michael Bell

The discharge coefficient of a square edged orifice plate or pipe is about

0.6. That of a well rounded entry or a conical entry like a venturi tube can be close to 1.0. Obviously if you're trying to suck seeds up off a surface you can't if the entry is conical because the air speed at the entrance would be too low but just rounding the ends of the pipe to as large a radius as possible or even adding a formed radius shape at the end with additional material would increase the discharge coefficient without dropping the air speed.

If you're introducing the seeds part way up none of the above is an issue.

I do have a different idea for you though. If you have a horizontal pipe with a light airflow going through it and you introduce seeds at one end you can grade them by how far away they land. Heavy seeds would land closer to the pipe. Light ones should blow away further. It would be easy to try anyway to see if it works. It might be too variable though but who knows.

Another thought is an angled pipe which gradually steps up in diameter. Suck seeds in from the bottom and they will rise to the portion of a diameter which matches the airspeed to their mass and sit on the step at the base of that section. Not sure how you get them back out again though - lol. Small hatch covers in the pipe maybe.

I could spend far too long thinking of ways to skin this particular cat.

That's what I am doing.

Thank you for all this, but these ideas need to be kept level and this is to be a PORTABLE device.

Michael Bell

Even nerdier. For an example of multiple sub- and super- scripts, it's probably about as complex as it gets. This is the final version, as a .png:

And this is the LaTeX required to create it:

-- Peter Fairbrother

What Dave said, though I'm not entirely clear about your question.

I can foresee a possible problem though: I don't know how efficient this method of sorting might be. You will need a good speed controller, if I am imagining your device correctly, and it may not work well enough anyway.

You might consider using lipo batteries - a fan takes about 200 mA at

12V, and a 11.1V 1500 mAh lipo is cheap enough (though the chargers ain't that cheap), and it will be very much lighter than a lead-acid battery. 1500 mAh would give you probably 5 reliable hours of use, and I don't imagine you'd be using it all the time.

Can I ask again, first can you eat alder seeds? and second, how big and heavy are they, and the cones?

-- Peter Fairbrother

Another thing, seed size is determined entirely by maternal genetics.

You are going to be looking for seeds from a tree which are larger than the average seeds - isn't it easier to just collect seeds from trees which produce larger seeds?

Why would you want to sort the seeds on-site anyway?

Seed water content will make a big difference here too, likely more than genetics.

I'm not at all clear what you are trying to do.

-- Peter Fairbrother

and position on the tree, sunlight, phloem/xylem connections, and so on

- but paternal genetic don't get a look in.

It's an up-arrow, Shift 6 on the UK keyboard

NO! The tissues of the seed are 50 - 50 maternal/paternal, so 50 - 50 genetic contribution. You wouldn't say that an unborn baby was 100% its mother's genes!

It certainly is true that some trees produce much bigger seeds than others, and of course it is those tree which I will focus on. But even within a tree producing large seed, some seeds are larger than others.

Because I want to breed from them to make even bigger.

There is no way I can control for water content.

I am trying to produce a variety of alder which will produce seeds as a grain. Plenty of trees produce fruit, apples, dates, palms, but none of them are staple crops, hard dry things with good keeping properties.

This country cannot feed itself. 40% of its land is "upland" which cannot grow arable crops. Arable crops come from the Mediterranean and are at the limit of their range here. That is what I am trying to correct.

Michael Bell

I have a rheostat (R S Components 170-304) and I have on order a speed controller (Type KC5225 from Jaycar

The likely duty cycle is;-

Pull cones off tree 2 minutes Crush cones 1 minute Run seed sorter 1 minute Walk to next tree 1 minute

I have a 1.2 AH lead-acid battery. It's not too heavy. I can't see myself running out of juice at this rate, but I could have 2, one for the morning, one for the afternoon.

Michael Bell

What you may want is uniform flow. The way that is achieved in a decent wind tunnel is to have a contraction in the tube with a '2q' screen across it. Called '2q' because the pressure drop across it is twice the dynamic pressure (0.5?V^2) of the approaching airflow Can't remember the spec.of such a mesh for sure but it's pretty fine stuff. Something like 30 mesh 32 gauge

Bigger seeds have more weight and more drag - which wins? Perhaps I should have followed some of the links given.

Henry

I don't understand this. Should this mesh be at the intake from "still" air or where the inlet taper changes to parallel sides? I have

1 mm wire mesh. Maybe I could get different if I knew what was wanted.

For spheres of the same density, the bigger spheres fall faster. It's a matter of weight/surface area.

Michael Bell