CadeJohnson

I have been investigating the fine art of dishing out a wooden chair seat for comfort today, and made discoveries that can be readily condensed into a, imho miraculously easy formula. So here goes:

Your "sitz" bones or ischial tuberosities are prominences of the pelvis that are the hard spots when you sit. They are pretty consistently located in adult humans as it turns out, though you'll have a hard time finding dimensional data if you go looking! I measured approximate spacing among a slightly inebriated and jovial crowd who endured the indignity with humor and made a rough prototype seat to check my theory. Drill two 2-inch diameter holes spaced five inches apart at center (3-inches of material remaining between the holes). For a finished seat, one would shape the edges, but don't even bother for this experiment - just drill the holes in a piece of lumber and sit down on it. shift around for comfort and when your ischial tuberosities align with the holes you will say aaah!

I will be making two holes in a rectangular stool seat at this spacing, centered about three inches from the "back" edge of the stool, and sanding smooth and dishing out the seat a little. I'll try to remember to post a finished picture, but I found this preliminary result too great and dramatic to wait.

Some individuals might be grateful for a third hole at the centerline and about two inches closer to the back edge - where a tailbone-afflicted person does not need hard support and an average person will not miss it. I have not tested this third hole yet, maybe others will report...

My rainwater collection begins with a first-flush and debris removal tank, but it is not ideal; all the water flows through it and in a big rain it can stay stirred up. So it has debris and because it is necessarily open to the roof this means some bugs in there. The outlet to the storage tank is wrapped with three layers of window-screen cloth, but the overflow is open to the drain. Frogs (cute little coqui tree-frogs) come up the drain and inhabit the tank. The storage tank overflow ties into the first flush overflow, so once in a while there is a tree frog in the first storage tank. There are no bugs in that tank so the frog will die if I fail to capture it (which they are very wily).

How can I keep a frog from climbing up the pipe while being sure I do not obstruct water going down the pipe?

Table top is four 50-pound bags of ready-mix grout concrete (no stone, just sand), 3m of 1m wide 1x2inch fence mesh.

Chairs were solid white upholstery. We bought them in a second-hand store and painted with diluted acrylic (to hide old stains). Waiting 30 days before I apply sealer to the concrete.

has anyone here ever experimented with an "electromagnetic" pump? If the pumped liquid is conductive and the piping is enclosed in a coil (think solenoid), and a current is passed across the fluid near the coil, then the magnetic field made by the coil should attract the fluid passing the transverse current (causing it to flow). As fluid flows toward the coil, new fluid starts passing current and so on.

Electromagnetic pumps are used in metal processing for continuous casting, but those are fancy and expensive devices. Could I pump seawater by wrapping a coil around a garden hose and pop-riveting a couple of electrical contacts into the hose on opposite sides next to the coil? I think regular "fresh" water would not be sufficiently conductive, but whatdoIknow? My longer term plan is to try pumping molten salt, but I want to learn on cooler stuff first.

I'm all ears!

At Laguna Cartagena, near Cabo Rojo, Puerto Rico (red bird with black chest and mask, perched on green leaves, lit by sunrise)

This is a video of my off-grid house in the Dominican Republic, which is featured in this community's title background. It is for sale, so buy it and you can be famous! lolz https://drive.google.com/file/d/16s22L6fgJRtxPQ-a6_aEWy8QJsgsWexN/view?usp=sharing

These EG4 batteries from Signature Solar look like a pretty good deal to me; $265/kWh according to their calculation. I paid a little over $500/kWh for some 12V form-factor lithium batteries at the start of the year and thought those were a reasonable price.

cross-posted from: https://beehaw.org/post/2196737

Like many of you, birds are very special to me. I connect with them like I don’t any other living creature, save my wife and kids. I photograph them. I’ve covered my body in nothing but bird tattoos.

To see that a THIRD of them have disappeared is like a knife to the heart.

Today's adventure: a couple of rainy days caused low battery levels, but not too low I thought - still 30% or so; these are lithium batteries and can deep cycle. They are "smart" batteries and if one is full in series, none can charge further - so they should all be at the same charge level all the time. But a couple had gotten out of step somehow and when they reached zero everything shut down.

How to bootstrap it? With no battery output (since a zero battery turned itself off and would not let the battery bank show any voltage!) - there is no way to activate the inverter and let street power run the battery charger. With no battery power, there is no way to turn on the MPPT controller and charge the batteries!

I could rearrange the banks to put four batteries with remaining charge in series because I have an 8-battery system, and get things restarted; but if there had been only four like when I first installed the system - I'd be in trouble.

Another thing that happened. Before I figured out the battery problem, I was trying to switch back to street-power. Because power from the street comes to the inverter first and then the inverter powers the distribution panel, when the batteries are down, I cannot get street power to the distribution panel. I could install a manual bypass, but it is not a commonly needed item and it is a large amp switch. So I removed the inputs and outputs at the inverter and bypassed manually. That worked fine. But in the process of disconnecting or reconnecting, I must have loosened the neutral connection to the inverter. So when the inverter was working again and I checked voltage, I only checked across the two hot legs - yay, 240V. I did not check that each leg was 120v from neutral! They were not: one leg was at zero and the other was at 240. I found this discrepancy fairly quickly after only destroying an outlet strip, the oven control electronics from a very old stove we were wanting to replace, and the controls of an old Sharp microwave oven with the 4, 7, 9 and Clear buttons not working. Woohoo we have a new stove out of the deal!

cross-posted from: https://slrpnk.net/post/611077

I have been thinking on how to claim every energy that comes on my plot. Technology goes more and more into harvesting the smaller left over energy. Ive seen examples in the Netherlands where startups try to get energy from a chip (I have been thinking on how to claim every energy that comes on my plot. Technology goes more and more into harvesting the smaller left over energy. Ive seen examples in the Netherlands where startups try to get energy from a chip (http://www.nowi-energy.com, https://memsys.nl) and a transparent solar panel layer on windows etc. Here in Lithuania sometimes the whole day has an overcast sky and that is the solar energy that we are getting. I know that with heavy overcast days a standard solar panels output can be as low as 10%. So a 5kWp can generate instead of 3.75kW produce only a meager 370W. My question to you, arent there other solar technologies that are adjusted to this overcast circumstances? So to gain more efficiency from diffuse lighting or from frequencies that can pierce the clouds more (like infrared spectrum)?

Some sunday morning pondering....

Some years ago, I was doing a little volunteer work with Climate Foundation, and I loved their long-term vision. It was based on these facts: 1) giant kelp is fast-growing brown algae that thrives in cold, nutrient-rich water. It is among the fastest-growing plants in the world 2) kelp thrives when there is abundant sunlight - clear water is much better for kelp than turbid water 3) cold, nutrient-rich seawater is present in oceans worldwide, but in the tropics, for example, it is present only below a depth of about 300 meters 4) kelp needs an anchor-point - it attaches and grows long fronds - it does not grow free-floating.

So the CF vision was to eventually build large kelp farm support arrays at a depth of 30 meters - suspended from buoys at the surface. Cold water would be drawn up from deeper ocean to create a suitable habitat for the kelp at the surface. But ships could still pass right over the platforms, if they could avoid the support buoys. These floating arrays would have the potential to support a vast new fishery in the tropics where pelagic fish are relative scarce in natural conditions. The fast growing kelp would absorb a large amount of carbon dioxide, and kelp fronds that sink in the deep ocean carry their carbon to the abyss where it is fixed for practical purposes for centuries, at least. Finally, vast kelp forests could support a range of industries; tourism certainly, but also a variety of chemical and food products that can be derived directly from kelp or with some added processing.