> I would experiment and try to re-word homework questions so that interesting StackOverflow answers appeared in search results.
That's a really interesting pedagogical approach, I like it a lot.
1,462 karma · joined February 23, 2012
Seattle, WA
That's a really interesting pedagogical approach, I like it a lot.
My understanding is that this is the motivating principle for the "bell" part of a rocket stove masonry heater. The hot exhaust from the combustion chamber is piped into a massively larger enclosed airspace, which has an exhaust port at the very bottom. Since hot air rises and cool air falls, most of the heat in the exhaust will be absorbed by the bell enclosure before finally being vented through the exhaust port. By enclosing the bell in masonry, it meets the design restrictions you mention.
I think it's also possible to build a masonry heater without using rocket stove principles, just a fireplace with a huge mass of masonry surrounding it. In that case, you'd want cladding with somewhat high thermal conductivity to capture the exhaust heat, but it's thick enough that the solution to the Fourier heat equation [0] is low enough to meet the design restrictions.
[0] https://en.wikipedia.org/wiki/Heat_equation#Heat_flow_in_a_u...
When sugar dissolves in water, it creates a solution, a chemical mixture characterized in this case by ionic bonds between water molecules and sucrose molecules. In general, the melting and boiling points of a solution will not be the same as the melting and boiling points of any of the individual substances that comprise the solution.
When I think about combining substances, I think about suspensions, solutions, colloids. (When I think about combining substances, I'm usually thinking about cooking). A suspension is small particles mixed into a liquid, but it isn't stable; after time or with a centrifuge, you can separate them back out. A solution is a chemical bond between individual particles of each substance, such that it is stable. A colloid is small particles mixed into a liquid or gas, but the small particles are so small that it is stable and cannot easily be separated out. Here's the link I used to refresh my memory enough to explain these concepts: https://lab-training.com/understanding-differences-solutions...
I'm sure you're aware of all that, but I wanted to write it out so I could be more explicit about my confusion. Adding water to solid rock will not result in a solution, colloid, or suspension. Adding finely ground rock and water can do so; that's kind of what mud or clay is. So I was confused how adding water to rock could result in any kind of mixture that changes the melting point of the rock.
Jofer's explanation makes sense to me: it's not actually adding H2O molecules to solid rock. Instead, it's that certain minerals under sufficient heat and pressure change mineral/crystal structure in a way that results in the precipitation/expulsion of various molecules and ions, including hydrogen and oxygen. Those precipitates diffuse through the solid until they react and combine with other minerals, causing transformations of those into new mineral/crystal structures with a lower melting point.
The link you provided talked about how solutions of sucrose and water in differing concentrations have different melting points, but I was confused about how rock and water could dissolve at all.
Where does the water come from? Is it liquid, or gaseous?
A "me thing", and this is just my interpretation, is something that is "about, of, or from me." If one tries to create the "best thing", it's impossible, because it's always possible to imagine another version that's somehow better. In trying to create a "best thing", I will strip or polish away aspects of myself that I see in what I create, because I'm chasing an ideal that is "outside of me", "objective", "universal".
If I instead choose to create a "me thing", that means accepting and celebrating that the thing I create will be a reflection of me, something that no one else can create, because it's imbued with the spirit of that who created it, namely, me.
Does that help, Laurent? It's not formal, grammatical English. It's not a common idiom, or a phrase I've seen elsewhere. But I think I intuitively understand what the author is saying, and I hope this explanation helps you understand too.
It also included a bunch of mathematics involving "neighborhoods", meaning the set of all points within a distance of an arbitrarily small epsilon from some point X. Although I never did any of the math problems from the book, that early exposure to epsilon made calculus vastly easier to understand, and for that, it's close to my heart.
Great Basin has a good hike to the peak, a cave system with guided tours, a nice (summertime) campground, and hiking trails to a really impressive arch.
Mt Lassen has a bunch of hikes, geothermal activity, lakes for swimming, a bunch of campgrounds, and some low-frills cabins.
Arches is always way busier than Canyonlands, but there's also a ton of non-NP features around Moab that are even less trafficked. Natural Bridges National Monument is also great. The Notom-Bullfrom road in Capitol Reef is a beautiful drive, and the campground out there is no-amenity, low-traffic.
Sand Dunes, in Colorado, is super cool, with hundred-foot-high sand dunes, but probably only 1-2 days worth of stuff to do in the park itself.
But if you want beautiful scenery without a lot of people, skip the national parks and look for the national forests. (Or sites in the National Park System that aren't National Parks, like National Monuments etc).
I thought it was a pretty cool story.
S. I. Hayakawa, Language in Thought and Action
Stuart Chase, The Tyranny of Words
An aluminum skillet from a restaurant supply store is cheap and low-maintenance. I use this one [0] for omelets and scrambled eggs, and it's probably my favorite pan. The thickness means that the heat is incredibly even, and there's enough mass that it won't cool down much when adding food to a preheated pan.
[0] https://www.foodservicedirect.com/alegacy-eagleware-the-poin...
It seems pretty ridiculous to me to assert that Coinbase stopping email price alerts is liable for investment losses, but the professor added the appropriate caveats, so my criticism is mostly with the publisher, not the source.
The interesting aspect to this, to me, is the idea that a/b testing could interfere with legal obligations (the article implies but does not definitively state that a/b testing was involved). I've worked on a/b test systems in ecommerce, and adding those obligations would have meant enough new requirements to substantively change the resulting designs.
This would be an interesting question to have to answer: If this test has a statistically significant result, would that mean one side of the population experienced better financial results than the other, caused by our actions?
I'm not familiar with the details of this accident, but in general, not necessarily. Air is normally an excellent insulator. But when voltages are high enough, the molecules ionize, become conductive and transmit current. This is a path-dependent process, meaning that once it begins, the voltage can drop below what is required to begin the process while maintaining current.
So an arc caused by a system with low capacitance (or total count of free electrons on the negative side) may quickly transfer all the free electrons, lowering the voltage enough to close the circuit. But anything connected to mains power will have an essentially infinite source of more electrons, meaning there won't be a voltage drop big enough to close the circuit. I'm being a little handwavy with the physics concepts, but hopefully the point is clear.
This can be thought of as a sort of hysteresis: the dependence of the state of a system on its history.
Edit: If you want to go down a rabbit hole, check out the solutions used in power substations as circuit breakers. It's not enough just to mechanically separate the connection, so they use systems like these:
https://en.wikipedia.org/wiki/Sulfur_hexafluoride_circuit_br...
https://www.codrey.com/electrical/air-blast-circuit-breaker/
Fear and Loathing on the Campaign Trail 1972 triggered in me an abiding fascination with the operation of the political process.
"They'd always ask it with the kind of voice people use in the presence of large sculptures in museums. They'd ask me, 'Have you read all these books?'" He waited again, but Billy Kinetta was not playing the game. "Well, young fella, after a while the same dumb question gets asked a million times, you get sorta snappish about it. And it came to annoy me more than a little bit. Till I finally figured out the right answer.
"And you know what that answer was? Go ahead, take a guess." Billy appeared in the kitchenette doorway.
"I suppose you told them you'd read a lot of them but not all of them."
Gaspar waved the guess away with a flapping hand. "Now what good would that have done? They wouldn't know they'd asked a dumb question, but I didn't want to insult them, either. So when they'd ask if I'd read all those books, I'd say, 'Hell, no. Who wants a library full of books you've already read?'"
His comics are amazingly good.
I worked at a company that had a codebase split fairly evenly between Ruby, Java, and Python. The Ruby stuff was the hardest to understand, and I think it was primarily because of using patterns around dynamically method definitions.