Hacker News: VygmraMGVl

New comment by VygmraMGVl in "Wax motor"

VygmraMGVl — Fri, 18 Sep 2026 04:16:12 +0000

Why does there need to be a thermal gradient? It seems like the action driving the actuator is the expansion of the wax due to temperature. You don't need a persistent heat flux to get that, the wax just needs enough heat warm up and change phase.

Edit: also, the actuation from the wax motor only happens while it is absorbing (or losing) heat, even if it later ends up in a steady state with no heat flux.

New comment by VygmraMGVl in "The bottleneck might be the air in the room"

VygmraMGVl — Sat, 04 Jul 2026 20:48:10 +0000

As an example of a negative result-- https://www.nature.com/articles/s41526-019-0071-6

Astronauts given two different batteries of cognitive tests showed no dose-response relationship to CO2 concentration

New comment by VygmraMGVl in "Meta caps internal AI token spending"

VygmraMGVl — Thu, 02 Jul 2026 02:02:57 +0000

At one point there were over 70 different token maxing dashboards as the management had a game of whack a mole trying to remove them. There definitely was encouragement from management about a year ago to increase ai usage, but once Claude code was allowed, they didn't really need to encourage anyone any more.

New comment by VygmraMGVl in "Meta caps internal AI token spending"

VygmraMGVl — Thu, 02 Jul 2026 01:19:42 +0000

The leaderboard wasn't leadership generated, it was engineer generated from internally available data. The leadership target is "impact" from ai tools.

New comment by VygmraMGVl in "MAI-Code-1-Flash"

VygmraMGVl — Tue, 02 Jun 2026 19:25:42 +0000

Claude opus 4.6 scores 51.9% on the same benchmark. Microsoft's result is quite good.

New comment by VygmraMGVl in "Meta's embrace of AI is making its employees miserable"

VygmraMGVl — Sun, 10 May 2026 23:22:35 +0000

Meta's interview process does include leetcode Hard and Medium problems (although the Hards tend to be on the easier side), but you don't actually have to write working code, just talk your way through an algorithm. I actually was surprised at how it didn't feel like I was being asked to brute force my way through a tough algorithm problem, but more felt like a whiteboarding session with my interviewer. YMMV but I found Meta's interview process to be the most humane "big tech" interview I went through.

New comment by VygmraMGVl in "Meta to start capturing employee mouse movements, keystrokes for AI training"

VygmraMGVl — Wed, 22 Apr 2026 03:59:55 +0000

It's pretty easy to scrape your own calendar events in Meta. I'm not sure about others' as I'm not a manager, but I wouldn't be surprised if it were visible as long as someone is in your report chain.

(I work at Meta)

New comment by VygmraMGVl in "'Strange metals' point to a whole new way to understand electricity"

VygmraMGVl — Sun, 25 May 2025 18:43:28 +0000

Typically, the behavior of any given metal is a mix of mechanisms so the measured behavior is fit to a curve where you fit n. So for metals the exponent is typically a decimal between 2 and 5.

New comment by VygmraMGVl in "Will open science change chemistry?"

VygmraMGVl — Sat, 07 Sep 2024 05:11:41 +0000

SoundBio is a bio + chemistry makerspace in Seattle. Not BSL, though.

New comment by VygmraMGVl in "How to debug your battery design"

VygmraMGVl — Sun, 28 Jul 2024 04:11:53 +0000

It would be interesting to see a blogpost on parameterizing a model in PyBaMM given a commercial cell. I imagine many battery engineers using simulation-based design tread over the same ground for determining parameters from literature, X-rays, etc.

New comment by VygmraMGVl in "How to debug your battery design"

VygmraMGVl — Sun, 28 Jul 2024 03:46:01 +0000

The "batteries-included" models in PyBaMM would apply to sodium batteries and lead-acid batteries (i.e. either the full Doyle-Fuller-Newman model or the Single Particle simplification). Flow batteries would probably require implementing a new model, which is supported in PyBaMM, since you need to model forced convection on either side of the separator.

I know PyBaMM has a relatively modular modeling system, but I'm not sure how they've broken down the models they have implemented.

New comment by VygmraMGVl in "South Korean telecom company attacks torrent users with malware"

VygmraMGVl — Thu, 27 Jun 2024 01:31:09 +0000

This was true in 2013 as well. I've heard this has changed in the last 5 years or so, though.

New comment by VygmraMGVl in "Impossibly thin fabric could cool you down by 16-plus degrees"

VygmraMGVl — Sat, 22 Jun 2024 17:36:19 +0000

Also probably a skin and lung irritant. Lots of people have contact allergies to macroscale silver and nanowires tend to get embedded in cells in soft tissue.

New comment by VygmraMGVl in "How to prolong lithium based batteries"

VygmraMGVl — Fri, 21 Jun 2024 18:39:09 +0000

It can affect battery longevity. If you charge lithium ion at cold enough temperatures, you get lithium plating which rapidly degrades capacity and can lead to internal shorts and fires.

New comment by VygmraMGVl in "How to prolong lithium based batteries"

VygmraMGVl — Fri, 21 Jun 2024 18:37:28 +0000

It's due to heat produced, gas generated from overvolting the battery, and stress gradients from different levels of charge across the battery.

New comment by VygmraMGVl in "Will any crap we put into graphene increase its electrocatalytic effect? (2020)"

VygmraMGVl — Mon, 01 Apr 2024 21:59:03 +0000

There isn't any difference between the guano graphene and the non-guano graphene in terms of structure -- look at figures 1 and 2. Figure 2A is clearly 4 of the same spectra because thermal exfoliation in the presence of guano doesn't create a materially different graphene than not in the presence of guano.

The rest of the paper is poking fun at all of the referenced papers that just have inconsistent electrochemical experimental setups that produce apparently increased electrocatalytic effects.

New comment by VygmraMGVl in "Lithium “shortage” bubble implodes again"

VygmraMGVl — Thu, 07 Dec 2023 21:33:11 +0000

Lithium is not a rare earth mineral. Typical weight fraction in ore is 0.5-8%.

New comment by VygmraMGVl in "The Federal Helium reserve is for sale"

VygmraMGVl — Tue, 05 Sep 2023 16:37:54 +0000

10 years ago, Congress decided we needed to transition off of it. Large amounts of the stockpile were sold off from 2013-2018 and this is the final part of the plan.

https://www.blm.gov/programs/energy-and-minerals/helium/fede...

New comment by VygmraMGVl in "SolarPi experiment 2: Finally something that works"

VygmraMGVl — Tue, 22 Aug 2023 02:54:01 +0000

Heads up, the danger with charging LFP at low temperature is that you will begin lithium plating. While this is a driver of degradation of LFP batteries, it's also a safety risk as lithium plating can lead to dendrite formation, internal shorts, and thermal runaway (i.e. fire).

Contrary to popular belief, LFP is not immune to thermal runaway. While LFP batteries do release less heat than Nickel based cathode chemistries, they can still cause a building to burn down when you have 200Ah or more.

New comment by VygmraMGVl in "Successful room temperature ambient-pressure magnetic levitation of LK-99"

VygmraMGVl — Fri, 04 Aug 2023 19:27:53 +0000

You drive current through the outer probes. The inner probes measure voltage and are not driven. When measuring non-zero resistance, you can vary the driving current to confirm the voltage you measure also varies linearly (ex thermal effects, capacitance of the material etc.). When measuring zero resistance, you can't distinguish vs a voltage probe error.