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Comment Re:Yes, obviously? (Score 1) 177

Generally by around junior year of undergrad as a physics major, you realize "holy shit, it's just progressively improving models all the way down - and none of these models get to a 'real' understanding of what's going on underneath the hood".

That's the reality. We don't know what quantum measurement or wave function collapse 'is', where the boundary between classical behavior and quantum behavior sits, why general relativity works well but we can't seem to get it to play nice with quantum mechanics - and the proposals to do so don't really yield a satisfying sense of understanding either.

Anyway, I find it very surprising that these would be revelations to any physicist. The thousandth time you write the "approximately equal to" operator as an undergrad or drop all the higher order terms from a diff-eq it is self-evident what level of understanding you can get from physics.

Comment Re: Smart (Score 1) 190

Current EV batteries have ~1500-2000 charge cycle lifespans.

That's at max charge/discharge rates.

Discharging a 70kWh battery pack by 70% at 5kW (the p90 of the power draw of my house) is 0.1C.

EV-class batteries used in residential solar systems with discharge at up to 1C and charging at 0.5C have warranties covering 3500+ cycles.

You'd need about 10c/kWh profit before it makes sense to sell back (or about 1c/kWh/$1000 it costs for a battery).

The price difference between peak and off-peak on PG&Es EV-A rate plan is at least 20c/kWh (partial peak) and up to 31c/kWh, for EV-B it's between 11c to 31c/kWh (at least in summer).

Comment Re: Smart (Score 1) 190

"nobody is going to want to use their expensive to replace EV battery in this way."

Surely that would depend on the rates offered?

If time-of-use rates were updated accurately reflect energy costs, it might become advantageous to do this (and fund battery replacements from grid credits).

Alternatively, in countries where feed-in tariffs are much lower than consumption tariffs, use the V2G to power the house and lower the electricity bill, reducing demand on the grid.

Comment Re: Smart (Score 1) 190

The summary says:

"Current time-of-use rates encourage consumers to switch electricity use to nighttime whenever possible, like running the dishwasher and charging EVs. This rate structure reflects the time before significant solar and wind power supplies when demand threatened to exceed supply during the day, especially late afternoons in the summer. Today, California has excess electricity during late mornings and early afternoons, thanks mainly to its solar capacity."

This is non-sensical.

The whole point of time-of-use rates is to encourage energy use when it is most abundant.

If the time-of-use rates were updated to reflect the times when excess energy is available, this "problem" would simply disappear, as EVs set to charge at the lowest price would do the right thing.

Someone here isn't thinking, but I'm not sure if it's the author or whoever sets the time-of-use rates.

Comment Re:Government stupidity (Score 2) 151

The main issue with these conversions is that the money assigned to turnover large-nationwide systems is allotted only once every 25 years or so. In developing countries especially so - since they don't have spare billions.

This is not the case in South Africa, where SARS is one of the most well-funded Government entities.

So even if they managers completely understand the pitfalls of this approach, they have to make the thing work until their next system upgrade grant comes along. This is why they adopt this interim solution. It's not *always* ignorance of technology. On the other hand, your comment betrays an ignorance of logistics and economics.

I think in this case, it *is* ignorance. If you don't agree, watch this interview with a previous head of IT at SARS (had been there for over a year at the time of the interview). You may want to start here and watch about 5 minutes, from where she talks about the migration off of Flash to where she says their "level of functionality is an uptime of 99.6%".

Comment Re:So ... (Score 1) 151

No, if you can't file online, you would have to complete submission on paper forms. Paper-based filing has an earlier deadline, so if you only realise when trying to file online, you would have to also pay a penalty. Also, South Africa's public services aren't very well run, so filing on paper will probably require spending 2 days waiting to be served at a SARS office.

Comment Personal income tax filing not affected (Score 2) 151

> As SARS tweeted on January 12, the agency was impacted by the time-bomb mechanism, and starting that day, the agency was unable to receive any tax filings via its web portal, where the upload forms were designed as Flash widgets.

The actual tweet says "SARS is aware of certain forms not loading correctly due to Adobe Flash.".

It doesn't say that all tax filing is affected.

Actually, October 2020 was the first time I haven't needed Flash to submit my personal taxes to SARS. For the past few years I have had to use Chrome, and in 2019 also jump through some hoops in Chrome to enable Flash, to submit my personal tax information, but this year I could just use Firefox.

There are other tax types that are impacted, but not all tax filing is impacted.

Comment Also North-hemisphere-centric (Score 1) 234

As someone living in the southern hemisphere (South Africa) who has regular (multiple times per week) meetings/conference calls with people in the U.S., DST is irritating enough as-is (with meetings scheduled to be at convenient times for 3 time zones, two of which are in the northern hemisphere and use DST and the other which doesn't use DST), where meetings move by an hour twice a year for participants living in a different timezone than the meeting organiser.

This 10-minute change every month obviously hasn't considered the impact on such meetings, which would drift by 20 minutes every month.

Comment My kids are already doing this (Score 1) 137

Two of my 3 sons are currently doing "light therapy" (among a number of other things including eye excercises), which involves:
* for one child, looking at a red light for 10m and a green light for 10m, daily
* for the other, looking at a green light for 20m, daily

This is treatment by a well-respected opthalmologist for heridirory conditions (which if untreated can lead to lack of depth perception due to the brain rejecting one eye).

Since I am finding it more difficult to read small text in poor lighting (even with glasses I mainly to prevent eye strain from working on a computer all day), maybe I should try the red light...

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