Hacker News Reader

mdturnerphyson Destruction of Nuclear Bombs Using Ultra-High Energy Neutrino Beam (2003)

It's a ring, so it should be thought of as something pi1000km in length, not pi(500km)^2 in area. The inside of the ring is not used for the structure. $32,000/meter sounds pretty generous.

mdturnerphyson Lamphone: Real-Time Passive Sound Recovery from Light Bulb Vibrations

That's an interesting claim. It's true in theory--the information is still there--but what's actually going to do the separation of the noise from the signal?

mdturnerphyson Lamphone: Real-Time Passive Sound Recovery from Light Bulb Vibrations

Whoops, should be "a better ADC won't help."

mdturnerphyson Lamphone: Real-Time Passive Sound Recovery from Light Bulb Vibrations

It depends on what the noise sources are. If you're ADC limited, sure, but if you're limited by something else--detector noise, air turbulence affecting the signal, variation in LED output, noise in the room--a better LED won't help.

mdturnerphyson Ask HN: I find writing difficult, how do I make it easy?

I've referred others to this essay on writing by pg: http://paulgraham.com/talk.html.

Also relevant:

http://paulgraham.com/useful.html

http://paulgraham.com/writing44.html

mdturnerphyson America is giving up on the pandemic?

That drop in daily new cases is due to a drop in NYC and neighboring areas. When you remove that area the daily cases shows an upward trend.

mdturnerphyson Optical Baking: CO2 Laser Browning of Dough [pdf]

I once laser engraved a few hundred digits of pi onto an apple pie for Pi Day, using a 400W CO2 laser in the student machine shop at our research lab [0]. By using higher power at faster scan speeds you can get depth rather than burning. I also once tried slicing slab bacon with it, with the goal of cooking it while cutting. I was pretty sure doing so would win the internet, but I aborted the attempt when it became clear the water content was too high and the grease would make a significant mess.

There's a group in Japan that had done a number of experiments with laser cutters and food, including using computer vision recognition to identify and then only cook the fat in a slice of bacon [1].

[0] https://guavaduck.com/laser-pie/

[1] https://fukuchilab.org/projects/laser-cooking

mdturnerphyson Two capacitor paradox

Adding the second capacitor is equivalent doubling the area of a single capacitor. If you had a plate capacitor where the plates were extendable you could charge it and decrease the energy by extending the plates, which tells you that there's a force that is pushing to extend the plates. Of course there is--the charges on one plate repel each other and "want" to increase their spacing. If you do extend the plates there is a force times a distance, which equals work done by the charges, decreasing the capacitive energy.

mdturnerphyson The Chiral Puzzle of Life

One hypothesis around the 20 amino acids relates to optimization of a quantum search algorithm [0]. Some recent work has added support to this idea [1].

[0] https://arxiv.org/abs/quant-ph/0002037 [1] https://www.technologyreview.com/2019/09/12/133081/an-import...

mdturnerphyson Employers are rethinking open-plan office design

From the HN guidelines:

Please don't post comments saying that HN is turning into Reddit. It's a semi-noob illusion, as old as the hills.

https://news.ycombinator.com/newsguidelines.html

mdturnerphyson Google deletes “communist bandits” from comments on Youtube

Same thing happened to this: https://news.ycombinator.com/item?id=20863498. I meant to email dang to ask about it but never got around to it.

mdturnerphyson A photo archive hidden inside a limestone mine

There is a similar storage facility in a mountain east of Salt Lake City where the Church of Jesus Christ of Latter-day Saints keeps geneological and church records.

https://en.wikipedia.org/wiki/Granite_Mountain_%28Salt_Lake_...

mdturnerphyson US Secret Service: “Massive Fraud” Against State Unemployment Insurance Programs

. . . a substantial amount of the fraudulent benefits submitted have used PII from first responders, government personnel and school employees.

Seems like this should have generated some red flags, as public sector employees haven't been subject to layoffs.

mdturnerphyson Why is 70% isopropyl alcohol a better disinfectant than 99% isopropanol?

It can also be confusing if you check the volumes after mixing, since the water-alcohol interaction decreases the molecular spacing and the total volume. V_(water + alcohol) < V_water + V_alcohol.

https://en.wikipedia.org/wiki/Alcohol_by_volume#Volume_chang...

mdturnerphyson Toilet Paper Orientation

I submitted this same page 6 years ago [0]. It's interesting how different the comments are this go around.

[0] https://news.ycombinator.com/item?id=7371501

P.S. Can anyone tell why my submission doesn't show up in the "past" search results for this?

mdturnerphyson Microsoft now blocks reply-all email storms to end our inbox nightmares

When the mailing lists are internal Exchange-based lists Outlook can check how many people are on them.

mdturnerphyson The Risks – Know Them – Avoid Them (COVID-19 infection event case studies)

If you can get further down there are links to papers about specific infection instances, but none about toilets.

mdturnerphyson 'Finally, a virus got me’: Scientist who fought Ebola and HIV reflects

This article summarizes some different case studies and scenarios: https://www.erinbromage.com/post/the-risks-know-them-avoid-t...

mdturnerphyson Onfim

What to Submit

On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.

https://news.ycombinator.com/newsguidelines.html

mdturnerphyson Foucault pendulum

The one at BYU has signs around it saying something like "Warning! 10,000 ohms! Do not touch!" I guess the thinking is that those who don't know what ohms are will think it's dangerous and those that do will have enough respect for physics to not disturb the pendulum.

mdturnerphyson Don't Mess with Texas

In Washington State the signs say "Litter and it will hurt" and show the fine for littering. The phrase has always seemed a bit awkward to me.

mdturnerphyson Jewish Problems (2011) [pdf]

Thanks for sharing. Best wishes in exploring your newfound heritage.

mdturnerphyson Flat HTML

It looks like the owner has shared it three times in the last 2 weeks, which suggests it isn't a joke.

mdturnerphyson Masks4All: Wear a mask to stop the spread of Coronavirus (Jeremy Howard)

I don't think anyone is suggesting that you donate used masks, but you make a good point that we shouldn't assume that someone wearing a professional-grade mask is wearing one that should have gone to a healthcare worker.

mdturnerphyson Masks4All: Wear a mask to stop the spread of Coronavirus (Jeremy Howard)

Yes! The page links to this document, which gives what appears to be a fairly comprehensive review of the literature: https://docs.google.com/document/u/0/d/1HLrm0pqBN_5bdyysOeoO...

mdturnerphyson Ask HN: How to self-study physics?

You might try Feynman's Lectures on Physics. They're available free online [0] or you can get a nicely bound boxed set.

[0] https://www.feynmanlectures.caltech.edu/

mdturnerphyson 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

Response from my friend:

Novel thought...

Theoretically, yes. The Environmental Control Systems on all our commercial airplanes positively charge the airflow at a nominal Delta P of 9.8 psi and have HEPA filtration down to 10µm, but at $100M+ per 737 MAX, delivery customers highly frowning upon such a practice and not being able to deliver them as a "New" airplanes after contamination, highly unlikely.

The A380 fleet is starting to retire prematurely only after 10 short years of service due to lack of profitability and demand due to COVID-19. Those huge retired Behemoths could serve very well as a quarantine base in remote locations.

mdturnerphyson 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

No flying needed--just need to pressurize the aircraft while on the ground.

mdturnerphyson 'Pandemic ventilator' could offer solution in potential 'worst case' scenario

I'll ping my friend who's been at Boeing for 25 years about it in the morning. Anyone know an MD who could review the idea?

mdturnerphyson “Just walk out” technology by Amazon

Skip [0] lets you scan and pay for items with your phone, so it doesn't require any infrastructure be installed but isn't as simple for the customer.

[0] https://getskip.com/