Recent content by DaveE

Yes, I do think it is possible that kids today don't need to learn the Riemann - Roch theorem. I don't think your birthdate is the issue in this case.

- Cloning mammals. Dolly the sheep was a bit of a surprise. - Gene editing (CRISPR etc.). Still early days, but I doubt Watson, Crick, or Pauling ever thought it would happen so soon. - Rapid, low cost DNA sequencing. Francis Collins didn't expect Craig Venter to do it that way. - Photograph...

All of the problems? No one does every exercise, do they? I'm pretty sure we did Goodman, Fourier Optics, cover to cover at school. Also maybe Protter-Morrey, Calculus, in high school. Otherwise I've found it very rare for an instructor not to exclude parts. In my working life, probably just...

OK, disclaimer... Native California guy here... So what? Today there were 8 M2.5 or bigger earthquakes in the US. M 2.5 is the smallest the USGS will even report. "There's no tsunami risk right?" - SMH. Slow local news day, I guess.

This was (is?) a significant human factors design issue with aircraft cockpit displays. In older or cheaper aircraft the gauges were (are) designed so that if the needle was in the middle (usually up) everything was sort of, mostly, OK. But if you saw a needle off to the left or right, it...

While maybe a bit off topic*... By "swim around forever" I think you mean without decompression stops in your ascent. Time at depth isn't a problem if you have enough air. Getting home safely is the issue. This is about air embolism (the bends). It's not about barotrauma (Rule #1: NEVER...

The article above is in this ball park. Recall that 33 feet of water is 1 atm. "Air embolism can occur in as little as 4 feet (about 1 meter) of water when people breathing pressurized air hold their breath while ascending rapidly. Pulmonary barotrauma can even happen in a pool when air is...

https://www.merckmanuals.com/home/injuries-and-poisoning/diving-and-compressed-air-injuries/barotrauma

Sorry, y'all missed my point. Scuba divers know that reduced pressure creates air emboli in you blood. Anyway, I don't think you can pressurize your blood with compressed air in your lungs. I don't think the alveoli are strong enough to withstand much pressure difference. Scuba divers also...

Clearly not a scuba diver asking. Even though space is cold, it's also a pretty good insulator. Heat transfer is from radiation and happens more slowly than anything related to pressure changes.

Alta used either 257nm or 244nm from a large frame ion laser, I don't recall. Diodes have a tough time with the shorter wavelengths. That company was sold to AMAT at their peak and spectacularly imploded, gone in 5 years or so. A multi billion $ mistaken purchase. AFAIK, KLAC still buys small...

I guess I'm not surprised I'm out of date here. I've been out of the tech game for a while now. We sold Ion lasers to Etec Systems* for many years for mask creation. Also to KLAC for inspection. * Now part of AMAT

Yes. Lasers are used at many steps, each tailored to their very specific task. There ate many applications; mask creation and inspection, wafer inspection before & after, photoresist exposure, annealing, dicing, via drilling... I'm definitely no expert, but I'd put my bet on mask creation as the...

Yes, they do. Single frequency TEM00 propagation is a thing people have been using for nearly 50 years. About as perfect as anything in modern technology. That's how the computer you're looking at was made. Also, for many lasers it's where most of the energy is in the far field even if they have...

Do you mean the laser beam, or the entire laser? What's in the vacuum? There are some laser applications that require a vacuum, but they are pretty unusual. One is very, very short wavelengths, often called "vacuum uv" because of the absorption by O2 and N2. Another application is in vacuum...