Syd Smith

Taylor McRae wrote:I have 1 acre and a bit of a slope and I'm considering swales too. Similar situation where there are times of the year we get a bit of rain, but dry spells in the summer that it would be nice to stretch out the water for.

Did you make up your mind yet?

Not really. It's such a gentle slope that it may just not do very much. I've gone back and forth about adding small, very shallow fishtail swales right around the bigger trees, but I do think building up and improving the soil with mulch will have a far greater effect on water retention. I think I may end up doing a little reshaping but nothing drastic on such a flat surface.

I do have some time to keep contemplating it, though, because I'm going to cover crop for this fall (once the tarps come up in a couple weeks) and then all of next season, and I won't be planting trees for a year and a half. If I dig anything, I'll probably do it between cover crop rounds next summer, so any soil that's disturbed has a chance to recover before the first real planting.

A jute blanket can also help a lot, in part because it's easy to pull out, soak and wring out, and then put back on top. Eventually the worms do eat through it, but then you can just give the remaining bits to them and put a fresh one on top!

r ransom wrote:
Calcite as I keep calling it may not be the best word, but easier to spell than calcium carbonate, seems to have several paths to aquire it.  Limestone, marble, chalk...and possibly eggs.

I think calcite is fine! Limestone, chalk (a type of limestone), and marble are usually all made of calcite, or sometimes dolomite (a magnesium calcium carbonate), but calcite is the most common mineral in all of your sources. Aragonite doesn't survive geologic conditions as well and tends to be replaced by calcite, so it's typically much more minor. The real differences between your sources should be the grain sizes and habits (shapes) of the calcite, rather than the mineralogic makeup.

Yes, New Zealand is especially extreme, and a great example of how there is really no universal volcanic agriculture scenario, at least for soil types. Most of your volcanoes erupt explosively and are more silicic on average, and some volcanic islands in subduction zones would at least have similar eruptive behavior. Others, though, not so much.

Jay Angler wrote:I am seriously considering an e-bike particularly for the range it will give me.

Here are some of my concerns:
1. E-bikes are *much* heavier. If I am in an accident, the weight of the bike alone may increase my injuries.
2. The "carrot" of going "faster", rather than simply "further" is real. An accident at 10 mph is safer than 20 mph is safer than 30 mph. Granted my area has many very serious cyclists who go waaaayyyyy faster than I am capable of going without electric assist, but I'm seeing more people going faster on flats and down grades on electric bikes and am concerned. There have been multiple articles from Emerg Doctors about electric scooters and how dangerous they are.
3. My concern is cubed for people riding with a child on the back such as the picture above. Just because you *can* go fast, doesn't mean that you might not have serious regrets if something goes wrong. I am totally happy with the idea of using electric assist to help me up some of our hills, and to help me go on a 20 km trip when I know my knees are only up to 10 km. Personally though, I'd rather a child be in a bike trailer with it's lower center of gravity, than on the back of a bike as shown above. This, of course, means I need to do some serious upgrades on my old bike trailer before my hoped-for grandchildren become a reality!

For the moment, I an still contemplating the issue. I am *really* happy that Wheaton Labs is doing some serious real life testing for us. One concern is with how long they will last, and which ones are truly repairable. It has gotten to the point with cars, that home repairs are much more difficult if not impossible. I don't want to have to loose my bike to a shop for months because of difficulty getting parts.

My experience commuting by e-bike every day was that you are really in control of your speed and just don't have to go so fast. It's not that hard to slow down: pedal less, use less assist, never use a throttle if you have a bike that happens to include one. I never liked the feeling of going as fast as 20 mph, so I just didn't do so... and I have a class-3 bike, so I could have gone faster if I wanted to. I might have exceeded 15 mph on long, straight sections with good visibility when I could see there was no one else on the trail and very low risk, but otherwise it's quite easy to hold yourself back if you prefer.

I found that if I wanted exercise, it was very easy to just lower the assist. If I was running late to work or fighting bad weather or just didn't want to show up to my job too gross, I might have used a little more. But it really wasn't as tempting as you might think to take unnecessary risks. If weight is a real concern, you can also just make the decision to save up for an ultra light model; they're very pricey, but do exist, and many of those models have great reviews.

I also found that while some of the parts were different (I have a class-3 ebike with disc brakes, CVT instead of traditional gears/derailleur, a mid-drive Brose motor, and a Gates belt instead of a chain), I could pretty easily learn basic repairs. I replaced the seat, fixed flats, re-aligned all the CVT cables (after I messed them up putting the tire back on), and adjusted and fixed the belt a couple times with no help and some basic tools. I'm moderately handy and can follow instructions, but not all that experienced with bike repair, and it really wasn't all that tricky.

After a quick skim, I did not see much discussion of Ride1Up bikes, but I'll make a little plug for them! They have very good quality parts for the overall cost, so they are a really good compromise brand where you can save a bit on cost while getting a really nice bike. I've had a Prodigy V2 for a couple years that I used primarily for my work commute (before relocating somewhere with no bike trails, no shoulders on country roads where people go 50 mph, general death trap situations), and it was just a fantastic bike. They also make other styles, of course.

Oh, also: water supply. Rainwater catchment can be contaminated by tephra fall, and areas with excessive gas release can have unusual geothermal groundwater properties. It's not just sulfur (though that's the most immediately obvious to the human nose, and a safety concern). Spring water and pools may be extremely acidic with high dissolved metals. Some geothermal waters are CO2 rich, and this is both good and bad: nice naturally fizzy water sources (and even CO2 bottling for profit in some places!), but risk of CO2 buildup and sudden release, which can be deadly.

Easy geothermal energy, on the other hand, is a great benefit for a volcanic region. That's a larger community or state effort, though.

I think this will depend so much on other environmental factors that it would be hard to be universal about it. Tropical volcanic areas where soils form from rocks and ash quickly will be very distinct from arctic ones where soil formation is very slow. The styles of volcanism and volcanic products in a place like the Congo would be dramatically different from, say, Hawaiian or Icelandic volcanism.

In tropical volcanic arcs, soil formation is pretty rapid, and soil quality is generally pretty good (not quite as good as a fertile floodplain, but there are nutrients to break down from the volcanic deposits). But ash deposits can be frequent, and ash is pretty smothering and unfriendly to plants and crops, especially when it's thick. Acidic vog from passive degassing can also be a concern, and CO2 buildup in low lying pockets near passive venting areas can also cause tree kill zones. Basically, these areas can be very lush but have intermittent kills and dieback, so versatility would be a priority. Heavy ashfall also causes structural and roof collapses, especially in wet tropical areas with a lot of rainfall.

Volcanic soil in general is likely to be on the acidic side, but islands in tropical areas may also have carbonate sediments, so I'm not sure that would be so hard and fast. The soil details would thus also be pretty localized.

Catie George wrote:Pure calcite, as a large crystal with few impurities, is very transparent. "Spar" calcite (very pure, very clear large crystals) is quite interesting, as it's known for double refractions - you see two images side by side if you look through it. I wonder if that would impact the apparent "glow"?

Once the grain size is small enough, you would see effectively full reflection and no light transmission effects, so you actually wouldn't see any double refraction effects. Most minerals that are transparent to light produce double refraction (calcite just has such high birefringence that you can see it with the naked eye in optical quality crystals), and it doesn't change how powders look.

Catie George wrote:
Basically - looking at the optical properties of pure calcite, i am not surpised that fine, pureground calcite would behave with a lot of transparency when added to oil. (And i wonder about silica dust, though likely less safe to work with).

Edit - After musing some more with respect to the transparency of calcium carbonate, i'd anticipate the SOURCE of calcium carbonate to make a big difference for transparency, possibly more than it's exact particle size/distribution, even with the same chemical formula, with a rough opacity scale of chalk (the kind from microscopic creatures) -> llimestone dust-> marble dust (ordered with increasing transparency). Marble is limestone after heat and pressure mushes it together and allows the crystals to rearrange themselves to be bigger and less flawed.

Getting way into the weeds - i wonder if particle size distribution also matters? For example, if the calcite crystals and the pigment crystals are both of consistent particle size, but have a gap between them (so the calcite is consistently smaller or bigger than the pigment) , i'd expect them to behave differently (smearing seperate, or settling from each other) in paint than if they were consistent.  I'd also expect if you have a wider range of particle sizes of calcite, smoothly graded between them, your paint will likely be better at holding it's shape.

I would bet that factors like hardness as well as color and availability all play a role in what minerals are practical to be used in this way. Silica would be much too hard to grind to a fine powder by hand in large quantities without significant tools, while calcite is soft enough for it to be reasonably practical. With limestone and marble, basically pure calcite (or dolomite) is also pretty straightforward to gather in significant quantities.

I think that the actual mineral grain sizes within the ground-up particles might be the real difference between these sources of calcite, and that could be the reason they behave and look so different. Any of these rocks could be ground to any grain size a person wanted, and could then be sieved for size consistency. But the limestone/chalk particles are probably microcrystalline and made of microscopic tinier grains, while with the sparry calcite, each particle would be a single crystal (all broken from much larger single crystals). The marble would probably be somewhere in between?

I teach and sometimes some of it is online! And I've had some formal instruction in current thinking about best practices. As a caveat, I find that student learning outcomes tend to be poorer online than in person no matter what you do, on the whole, even with identical content, and I think the reason is that students need to be more self-directed and disciplined to learn from videos and other online materials. But for some students it works great.

Here are some tips:

Short videos (5-10 minutes) are far more effective than longer ones at holding attention and communicating ideas. If you have more content, break it into separate videos.

If you have a way to break up a video by asking the student to pause, write down their own ideas, and then check back in, that can help replicate in-person teaching methods where students think and problem solve (as long as the student actually does it).

There are tools you can use to create online interactive activities, quiz questions, and other components that help with interaction and engagement. A lot of them aren't free, so it helps if you teach with a school that subscribes to some of these services. But you can probably do some basics with free tools like google. Videos alone can create the "illusion of learning," where you think that because you have checked off a task and watched a video, you have learned everything you saw. Self-testing (where you don't immediately reveal all the answers) is a more effective study habit, so building in some tasks that accomplish this can really help students learn better.

If the course is offered to a group instead of being completely independent and asynchronous, you can build in group discussion boards to share ideas, even if there are no synchronous lecture meetings. I have found that having one required discussion board at the end of each module where the students are instructed to just ask one thing they are unsure about is enough to get them interacting sometimes, and it also offers an opportunity to follow up and answer their questions.

Hope this is useful!