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Obi_Juan_Kenobi commented on Anatomy of a credit card rewards program   bitsaboutmoney.com/archiv... · Posted by u/disgruntledphd2
ThrowawayTestr · 2 years ago
>this is why crypto never took off as a replacement for credit cards

I thought it was because transactions take minutes instead of seconds.

Obi_Juan_Kenobi · 2 years ago
They can take either; waiting for confirmations is only a matter of reducing double-spend risk.

In practice, seconds after a transaction has been signed and broadcast, it is already very unlikely to double-spend. Miner incentives are such that the first-seen transaction is the most likely to be used. A delay of a couple seconds is sufficient to account for network-propagation lag.

You wouldn't do this for high-value transactions, but there's some threshold where real-world risk is lower than the convenience of a fast transaction, and that threshold is reasonably high.

Obi_Juan_Kenobi commented on How I replaced deadly garage door torsion springs (2002)   truetex.com/garage.htm... · Posted by u/bronzekaiser
elzbardico · 2 years ago
The people answering apparently don't know that you can use counter-weights, cables and pulleys instead of a torsion spring. It takes more space, but it rock solid and safer to fix.

It is very common in some other countries.

Obi_Juan_Kenobi · 2 years ago
Counterweights provide a constant force, whereas springs can be precisely balanced to the decreasing weight as the overhead door becomes more horizontal. It is inherently related to the design of segmented overhead doors.
Obi_Juan_Kenobi commented on New images and video confirm Austin-made Tesla model Y has cracked front casting   autoevolution.com/news/ne... · Posted by u/clouddrover
trogdor · 3 years ago
When you buy a Tesla, you agree to arbitrate all disputes with Tesla.

Including Lemon Law claims.

Obi_Juan_Kenobi · 3 years ago
They can write whatever they like; state law dictates how it actually proceeds.

In my state, you must start with arbitration but you have zero obligation to accept that decision and can sue regardless of outcome.

Obi_Juan_Kenobi commented on LK-99: Team of Southeast University observed zero resistance below 110 K   twitter.com/lipez400/stat... · Posted by u/thecopy
gchadwick · 3 years ago
Certainly no expert here but if you take the original video and replications at face value it does exhibit strong diamagnetism at room temperature. Superconductors are diamagnetic due to the Meissner effect at their superconducting temperature. This would mean LK99 is a superconductor at low temperature and separately be strongly diamagnetic at room temperature (no Meissner effect if it's not super conducting). Would that be unusual?
Obi_Juan_Kenobi · 3 years ago
The premise is flawed because that assumes the samples they are studying are identical.

Replication is difficult, and particularly difficult for novel processes where the important variables are not well understood. It could be that the methods were reported as accurately as possible but still leave out critical detail(s).

Obi_Juan_Kenobi commented on Red algae proteins grafted into tobacco double plant growth   news.cornell.edu/stories/... · Posted by u/geox
Ultimatt · 3 years ago
Tobacco isn't a model organism at all. Solacea genomes only really got sorted in the late 2010s. Its worth pointing out if you could do something in Tobacco you could have done it in Tomato or Potato, you know those crops that dont kill people globally but sustain them. Arabidopsis thaliana (a type of cress) is the small plant model organism, not because it's biologically significant, but because it had a tiny diploid genome that could be mapped early and it's easy to grow quickly in a lab and seeds fast.
Obi_Juan_Kenobi · 3 years ago
Benthy, maize, and arabidopsis are the three major plant models. Hundreds of labs specialize in benthy, thousands more use it. It is absolutely a model by any conceivable definition of the term.

One of the primary reasons it is a model is due to transient expression in the leaves via TMV. You can quickly assay many constructs on the same plant with a simple overnight experiment.

Obi_Juan_Kenobi commented on Mexico's heirloom corn strains are resurging amid more demand   nbcnews.com/news/latino/h... · Posted by u/DocFeind
zwieback · 3 years ago
Has anyone grown heirloom varieties in their home garden and is it worthwhile, e.g. does it taste good or is it more for the nostalgia factor?
Obi_Juan_Kenobi · 3 years ago
Most people grow sweet corn in their gardens, so they won't be growing these.

There are heirloom sweet corn varieties, but they have to be cooked in minutes/hours from harvesting to remain sweet.

As far as the starchy corn, you won't get a lot of flavor difference.

Obi_Juan_Kenobi commented on Rooftop wind energy innovation claims 50% more energy than solar at same cost   pv-magazine.com/2022/10/1... · Posted by u/fairytalemtg
taftster · 3 years ago
Just to ask. Do you think the housing of the turbine would somehow "channel" the wind it collects into the blades? And therefore increase the performance or yield against the size of the blades? Maybe in this way, the comparison is legitimate, that a smaller turbine blade (as in this case) can collect more wind?

I'm honestly not sure if that holds up properly, like from a true physics point of view. But it kind of makes sense from intuition. It would seem you'd get quite a fast moving turbine blade with this configuration.

Obi_Juan_Kenobi · 3 years ago
What they're really after is using the structure to direct the wind and create stronger flows by the lip of the roof. This is not a new idea, but perhaps they have hit on a shroud design that works more effectively.

I have little doubt that it can produce impressive figures in very specific conditions - many designs do - but I doubt they see vastly improved real-world performance.

Obi_Juan_Kenobi commented on Rooftop wind energy innovation claims 50% more energy than solar at same cost   pv-magazine.com/2022/10/1... · Posted by u/fairytalemtg
mrb · 3 years ago
You can see technical drawings of their device in their patent (US 11391262): https://patentimages.storage.googleapis.com/26/02/b1/f9004c8... The article calls it "motionless" and "bladeless", but this is patently (hah!) false. There are actually spinning blades... See figures 16c, 16d, 19 in the patent: the blades are in the turbine underneath the central body element.

At first sight, given the quantity of material used in the device for the foils and central body, relative to the small turbine size, it's hard to intuitively picture how or why it can be more efficient than a regular wind turbine built using the same amount of material which could, therefore, have much larger blades.

Edit: in fact the inventor of the device, Carsten Hein Westergaard, previously published results from a prototype https://iopscience.iop.org/article/10.1088/1742-6596/2265/4/... in which he claims the prototype achieved an efficiency of 42% of Betz limit, which is inferior to standard utility-scale turbines (Wikipedia claims 75-85% but I haven't checked sources: https://en.wikipedia.org/wiki/Betz%27s_law#Betz's_law_and_co... ) so that seems to confirm my intuition.

Obi_Juan_Kenobi · 3 years ago
> efficiency of 42% of Betz limit, which is inferior to standard utility-scale turbines

That isn't surprising at all; wind generation scales very very well with larger size. If it actually achieved 42% at that size, it would still be a major innovation.

But that's also a strong claim that requires very strong evidence. The reasons for inefficiency at smaller scales are fundamental: higher drag to lift. Essentially what they're doing is using the existing building as part of the device to direct wind. This is not a new idea, and in favorable conditions you can get some impressive numbers. But in real life..

https://www.renewableenergyworld.com/storage/small-wind-turb...

Obi_Juan_Kenobi commented on In 2019 RX470 were $70, RX580 $100   postadio.com/PC_Master_Ra... · Posted by u/albxxdx
alchemist1e9 · 3 years ago
I keep reading there will be all these cheap GPUs available, which is great, but I then ask where I can buy them but all I get is ebay, and then when I check ebay, they still aren’t cheap. Where will all these miners be selling them? So I can buy a few.
Obi_Juan_Kenobi · 3 years ago
It's just starting to kick in.

Most miners stuck it out to the bitter end. Hashrate was only down around 20% from the peak at the switch to PoS. Then it takes a few days to take apart the rigs and get them ready for listing. And that's only for the ones that aren't trying to mine something else, or simply are in denial.

But the main counterpoint to the GPU supply increase is the pent up demand from two years of usurious GPU pricing. A lot of people are ready to finally upgrade as soon as prices are reasonable.

Expect the market to soften - and it is, 3060ti prices are down like $40 over a couple days on eBay - but I also wouldn't expect bargain prices.

Obi_Juan_Kenobi commented on In 2019 RX470 were $70, RX580 $100   postadio.com/PC_Master_Ra... · Posted by u/albxxdx
bravetraveler · 3 years ago
One thing I find kind of interesting about this -- the folks dumping cards on the market had farms. Those running mining farms are playing a numbers game

This involves under-clocking and under-volting the cards, while also ensuring they're cooled well.

I think an argument could be made that mined-on cards are more well cared for than those owned by your average gamer.

There's not some 'destroy the ASIC' instruction. Work is work.

Mined on cards undergo fewer duty cycles, I wonder how the calculus works out between one long mild duty cycle compared to many more that are also more extreme.

Obi_Juan_Kenobi · 3 years ago
They usually undervolt/clock the GPU, but not the memory. VRAM temps can be an issue and only some miners will try to address that properly with copper shims, etc.

The 3090 is notoriously bad for mining because it has memory chips on both sides of the board, leading to more heating in one spot and poor cooling for the 'back side' chip. Other cards tolerate it much better, but it can be an issue.

So while overall mining cards should be good, there are some specific issues to watch out for. A failed memory chip is not an easy fix, requiring a reball/replacement of that chip.

u/Obi_Juan_Kenobi

KarmaCake day2308July 22, 2014View Original