bernulli

Yep, this is it. Ever wondered why syllabi and problem statements are so long, convoluted, and oddly specific? It all boils down to "Fool me once, shame on me. Fool me twice, it's going in the syllabus." [0]

Edit: I did not come up with [0], but I also don't remember where I saw it.

You can only have a net outflow of water if the air is not saturated with water, which is a function of the air temperature. If it is saturated, a dynamic equilibrium will establish, where water molecules from the air jump back into the surface of the liquid film.

That's why a 100F day in Arizona (dry!) will be much more pleasant than a 100F day in Florida (humid!) - if it's dry, your body can still get rid of the heat. If it's humid, it will just 'stick to your body'.

> why education at all?

It seems I addressed that in my post?

> Would you apply your same approach/attitude to elementary school education? At what point is it that we shift the burden to learn to the student?

I'd say the ideal is that a person is a curious self-starter throughout their life. But we have to differentiate between different degrees ( as in `levels') of education. I think that everyone needs some fundamental understanding of the the world (history, physics), needs to be able to read and calculate simple things.

And there are indeed schools who do it from an early age, like Montessori, in which students essentially pick their own projects.

Also, we do give up on educating a large segment of the population eventually: not everyone has a PhD. But we're not worse off as a society, because the returns are diminishing quite a bit.

I disagree. I think learning to learn, and, first, learning to motivate yourself to learn is a huge part of a college education with the goal to prepare you for a life in which boundary conditions change all the time.

What happens to those students who are then in a job, tasked to solve a problem, but now expect their boss to dance around them to make it `interesting'?

That's got nothing to do with west vs. poor. Have you seen the 2-year French math requirements before you are even admitted to an engineering school? Have you seen German universities where there is zero advisement and where your two years worth of math courses in your engineering program are tested in a single final exam, as the very first feedback (no quizzes, no homework, no midterm, not split into 10 math micro courses, no projects, no extra credit, etc.)? It's sink or swim.

But the material is not the problem. You have the whole world knowledge at your fingers, in books, the internet, etc. Schaum's outline will give you hundreds of worked problems. The problem is that the student sees no possible solution to this if she is not handed the solution by her instructor.

>Does it? If by clear you mean "relating to the anecdote you shared at the top of your comment", then sure - but that is far from my standard for "clear," at least.

It's a temporal correlation that all my colleagues observe as well. Average grades drop by 50% using the identical material that was always successful pre-pandemic.

So you find it more likely that lockdown, restricted gathering in learning groups, Zoom lectures, potential financial hardship had no impact on learning whatsoever? That's not quite up to my standard.

It puts the responsibility on the student, like it will be on the job. You have all the material on this planet at your disposal. Works in other countries: lectures and classes for two years and then one final exam. No quizzes, homeworks, extra credits, etc. Just the classes, lectures, you, your self-motivation, your peers, and all the knowledge of the world in books or the internet to help you learn the topic.

> STEM education that would withhold a critical tool

How does it do that? Are students locked away? Is there a secret police that storms into dorms and burns all material that students try to learn from? Does the Dean come in to break up illegal learning groups?

Tried that after discussion with students, with the result that no one did homework and the learning outcome completely collapsed.

The article perfectly reflects my experience teaching STEM in the last semester.

Instructional material that led to rave reviews and amazing student outcomes the years before now results in similar reviews like “lost a lot of respect for the Math department after taking this course.”

The main complaint is "Why won’t anyone teach me XXX": "it seems like the instructor is expecting us to learn the material ourselves".

Sorry to say, but for many STEM topics that's the only way. You need to struggle, do, and solve the problem. And not only there: you won't learn figure skating / cycling / playing an instrument by watching a lecture (or video) on it. You have to actively do it. The instructor can lead you to the water but can't force you to drink. Just staring at the water and complaining does not help.

I wonder what these students will then feel like in their first job. You hire engineers because you have a problem that needs solving. This kind of graduate on the other hand expects that someone solves the problem for them and feeds the solution in small packets.

Also, of course, it's interesting to wonder why this is happening now and if it will go away. The connection to the pandemic seems clear, but how exactly?

It's really cool how a Mach number emerges from traffic flow, with speed of cars vs speed of information, completely with shock waves and everything!

43 is still much less than 303, according to the math I learned in school.

Just read my first post and that should tell you everything that was wrong with your title. Because you insist on your alternative fact that 303 is somehow less than 39, I think propaganda is the right interpretation of the spin you are trying to give this story.

Well, you should have 'judged relevance' that more carefully then, because your submitted title is factually wrong, by a long shot.

Which is not what your headline submission says. Also, the article makes no statement about the relation to the vaccination status.

The propaganda headline has nothing to do with the article and also is completely wrong. According to [1], daily deaths now at 39, but on 01/31/2021 7 times that at 303.

[1] https://www.worldometers.info/coronavirus/country/portugal/

edit: typos.

Sure. But another key feature of how the turbine works is -- that it spins. That means that you need bearings and seals that can not only withstand but actually work effectively under those conditions.

Sure, and in the gas turbine combustor there are also no moving parts. But there’s lots going on outside.

You don't have the full temperature of the chamber b/c of the film cooling discussed in the article. Also, the chamber doesn't spin at tens of thousands of rpm.

In Germany, the overall entry requirement is a not horrible high school degree (type of high school intended to prepare for an academic career) for engineering. You can just go and sign up to the university of your choice. The flip side is that you then sit there with hundreds of other students that will be weeded out by a harsh curriculum and zero advisement. That said, whoever gets through that system will be worth their price later on when you hire them.

Minor nitpick: fluids are not either liquids or gases, this is particularly true for rocket engines where many of the discussed processes (injection, compression, regenerative coolant flow) actually occur at super- or transcritical conditions.

Also, I don't think you can say the faceplate is heat sink-cooled. Remember that just behind it is the propellant manifold, so it's rather some form of regenerative cooling.

Also try to imagine the thermal stresses when you have cryogenic propellants on the pump side and hot exhaust gases (gas generator or staged combustion) on the turbine side!

Excellent detailed advice by the others in this thread.

Let me add what I think you can bring to the table: a track record in getting things done. The only thing a professor has less of than money is time. If you can convince a PI that you can implement stuff more reliably than ‘mere’ students, without having to be held by the hand all the time, that’s a winner.

Interestingly, it’s an entirely different class of flow! A traffic jam is akin to a shockwave in compressible flow (e.g. gas), here the article talks about (incompressible) liquids.

It's really not - just by having more hardware available (at higher total expenses) doesn't make the pool of money available (public research funding) to book time on these things more. These things are one-off, you build a new one if you expect 10x improvement over the old one.

We don't need a fleet of X1 to break the sound barrier for the first time. We do need many Airbus/Boeings to fly people and stuff from A to B.

Note that that is the case with the unique research hardware you cite as well - we're not sending another Spirit/Opportunity, but have graduated to something else.

Soyuz is a different use case, as there is an economic demand to be filled - that's why a private company like SpaceX is in that sector with its Dragon. On the other hand, you don't see SpaceX cranking out Spirits or JWSTs or Washington Monuments.

He was decidedly not right. His claim was that neural networks are fundamentally not able to perform an XOR step, limiting any relevant computational capabilities. That claim was easily remedied later by slightly changing network architectures later on.

It's a really tough question of when to pull the plug. Marvin Minsky wrote a whole book in 1969 'proving' that neural nets cannot, fundamentally, do anything interesting - yet, here we are.

Thank you!

Is there a set of measures/activities holding up better to scrutiny that you could recommend?

You can very much model expansion in a nozzle as isentropic, but I did miss the part where the original comment was restricted to JT. Thanks!

I did miss the part where the original comment was restricted to JT. Thanks!