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guepe

274 karma · joined February 5, 2015

elepercq@synopsys.com
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guepe··on SpaceX wants to launch 100k more Starlink satellites for 100x the bandwidth
You can see them very easily at dusk. It’s dark enough but they are still in sunlight making them very clearly visible. There is always one or more easily visible (by design).
guepe··on IEA: Solar overtakes all energy sources in a major global first
Fuel was created by the explosion of supernovae, still solar but not our sun.
guepe··on UK company sends factory with 1,000C furnace into space
Note that growing ingots is an incredible feat at that purity and size that they achieve on earth. It’s already a very very hard step in a crazy process for entire chip manufacturing.
guepe··on I bought the cheapest EV, a used Nissan Leaf
Rivian I think it’s eating the extra buffer but that also means that the worse degradation that happens in first year is « free ». Then stats are a few percents per 100k miles…. There are articles about stats on long term degradation - it’s a non issue. Buy used if you can in USA - people perceive them as degraded so price is cheap but they don’t degrade fast
guepe··on I bought the cheapest EV, a used Nissan Leaf
This is completely avoided and not my experience. This is only because the leaf is not actively cooled. Most ev do not suffer from such difficult management of battery and have a computer dedicated to cool / heat and keep battery in healthy temps.

They do degrade over time but very, very slowly. Absolutely not like phones. Mine has 25k miles and zero degradation yet.

guepe··on The $5000 Compression Challenge (2001)
There is a polynomial expression that will match the file. I wonder if expressing it would be compressible to a lower size than original file? [edit] I’m wrong - not all sequences can be expressed with a polynomial.
guepe··on Highest-Voltage Electron Gun
Ah! That “well” is exactly what I couldn’t understand from ion thrusters, where they shed electrons as they expulsé ionized gas. All I could find was “to keep the same charge”, but since there is no absolute ground, what’s the problem?

You just explained it :)

guepe··on Highest-Voltage Electron Gun
That reminds me of a question I was asking myself: instead of using rare gas for ion thrusters… why not ejecting very high velocity electrons ? Their mass is much, much smaller than any atom, but why wouldn’t that lead to a thrust ? Possibly without limit except power - no limit on a “tank”?
guepe··on New technology and old tactics have made buying a car a death march of deception
I don’t want my comment to feel like an ad, but I got a Rivian over the winter and it’s a similar process: it is a fantastic experience!
guepe··on AMD announces the Spartan UltraScale+ FPGA family
Yes they are.
guepe··on Xkcd: Greenhouse Effect
Plugging the numbers using France latest EPR: 20B for 1.2GW is 16M per MW Batteries mentioned : 1.7B for 300MW for 16hr is 5.3M per MW for 16hr

So compared to EPR, we could spend another 10M per MW for production…. I saw a relatively conservative price of 2000$/kw AC at https://atb.nrel.gov/electricity/2023/utility-scale_pv

That’s 2M per MW. We can spend 10, an over capacity of 5x ! And that is not accounting for the price of money, it takes very long time to build a nuclear power plant, and you will have your PV plant in the year, probably a couple for mega pack due to demand.

To me, nuclear is not the future.

guepe··on Xkcd: Greenhouse Effect
That’s interesting. The quotes for the nuclear power plant are really low though. France, which has a lot of knowledge and trained workforce for nuclear, is slowly building a reactor of 1.2gwe for like 20B euros. If you use those numbers… it looks very different. And that’s at least not idealistic price since it’s they are completing the construction.
guepe··on Xkcd: Greenhouse Effect
I’m interested in details. Nuclear is very expensive and not going down, while batteries are. So with your analysis, it could be possible to estimate how low batteries have to go before meeting nuclear… It could be irrealistic but let’s see !
guepe··on Amazon and iRobot call off their planned acquisition
I have two (vacuum and mop) and I’m happy with them. Slow ? Yes. Who cares it gets done in the day while I work ! Effective: yes.
guepe··on GE Vernova announces order of 674 wind turbines, providing 2.4 GW of power
Example in UK, offshore (with higher costs than onshore) are about 60 pounds/mwh (lcoe, so all included). That's 6 cents /kwh and this is offshore

But UK has lots of offshore wind. Still the 10cents upper range is probably quite a bit higher than the real number here.

guepe··on Time to short Japan's 'bad governance' stocks, hedge fund says
There is a fundamental reason for low inflation / growth in Japan: demography. No children, very aging population. I think normalizing growth by population growth would give some interesting insights about "real" growth, or lack thereof.
guepe··on How flip-flops are implemented in the Intel 8086 processor
Xilinx/amd fpga have a CE pin on many of its flops (if not all?). Not sure for altera/intel but would be surprised they wouldn't have.
guepe··on How Jeff Geerling almost broke MrBeast's 1-100 video [video]
De bouncing is solved in hw with right-sized capacitor. That's it....
guepe··on In Phoenix, this is life at 113 degrees for more than 20 days
Sources? I haven't seen that (yet)
guepe··on AMD Introduces World’s Largest FPGA-Based Adaptive SoC for Emulation
I'm close to this (I work in emulation) and that chip IS awesome. It is the first fpga really designed with emulation in focus.
guepe··on DJI drone flight log viewer
Ahah I actually once looked for such tool AND even started writing one. Raising two kids got the better of me!
guepe··on Some employers have decided to build their own housing for workers
Ski resorts house employees - at least it's very common in that industry. So clearly not illegal.
guepe··on No Mow May, Low Mow Spring
There is a strong advantage to regular mowing in my area (new england): way less risk of ticks. It's a real problem a'd with kids that spends time outside, ticks can be real scary. I got a few bites on myself and once on a kid, thankfully without side effects.

What is impact of more natural landscaping wrt ticks in 'ew England?

guepe··on Starship Flight Test (Launch in 1 hour)
I recall old interviews stating 3 off is fine for nominal flight of a loaded starship. It was empty (no payload) so probably more failure is ok.

But there are limits on how assymetrical the boosters force can be. With 5 then 6 out I wonder if spin was due to too much assymetry. I hope we get more details.

guepe··on California to lend 20% down payments with 0% interest for homebuyers
Montreal has like 30 or 40 years of rent control. The downside is landlords don't invest in renovations.

It does make montreal the most affordable large city of NA.

So in theory I'm sure you are right, in practice it's not what is observed.

guepe··on Everything advertised on social media is overpriced junk
Noted ! Mine sucks so I'll check it out.
guepe··on Everything advertised on social media is overpriced junk
Do you happen to have a summary of your findings somewhere ? I'm all to improve my sponges, umbrellas, etc... !
guepe··on Double-slit time diffraction at optical frequencies
My quantum physics classes are far back and that explanation nailed it for for me.
guepe··on EU countries approve 2035 phaseout of CO2-emitting cars
Even on grid using a ton of coal, ev more than compensate extra co2 generated during battery production. On the not so green us grid (average of us), ev save 50% co2 over their lifetime. But the grid is greening and so they are saving more and more. In france it's a factor 5.

ICE as the dominant form of locomotion is dead. People don't know it yet.

Of course some will be used for specialty work, but they will become a rarity in our lifetime.

guepe··on Bank failures come in waves
If you buy t-bills yourself fees are low, and brokers aren't banks - so risk of money being stuck there is low.

It's a bit of work but very manageable. 10/10 recommend, you earn more than a savings account.

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