D_Alex

Karma: 541

D_Alex 22 Jan 2017 9:57 UTC
5 points
on: Infinite Summations: A Rationality Litmus Test
In the “proof” presented, the series 1-1+1… is “shown” to equal to ¹⁄₂ by a particular choice of interleaving of the values in the series. But with other methods of interleaving, the sum can be made to “equal” 0, 1 ¹⁄₃ or indeed AFAICT any rational number between 0 and 1.

So… why is the particular interleaving that gives ¹⁄₂ as the answer “correct”?

D_Alex 27 Oct 2015 3:04 UTC
−4 points
in reply to: tut’s comment on: Crazy Global Warming Solution Ideas

“Powerwall” is just a big battery.

Yes… plus some electronics, like a rectifier, an inverter and control circuitry.

It might help compensate for the irregularities of solar and wind power.

Yes… that’s partly what is was conceived to do. It also can compensate for the irregularities in demand.

But it only makes sense to use batteries for that after we have moved to much more renewables.

For storage of solar and wind power, this is a complex matter, and the short answer is “it depends”. For demand management, it makes sense now.

It is much more efficient to store the power in the water magazines of existing hydro plants.

It is desirable to use hydro plants (where they exist) as swing producers. Pumped storage is not quite as energy-efficient as battery storage (roughly 75% for pumped vs 85% for Li batteries), though it can be cost-effective, in places where large, elevated reservoirs already exist.

But all this is besides the point, which is: There are proposals to “solve” global warming, which are implementable now, with today’s technology, which furthermore have side effects which are on balance positive (like clean air in the cities).

D_Alex 26 Oct 2015 3:00 UTC
−8 points
on: Crazy Global Warming Solution Ideas
Do we really need crazy ideas when we have good ideas that just need to be implemented? For example, transitioning to an “electric economy” as proposed in Elon Musk’s Powerwall launch:

https://www.youtube.com/watch?v=yKORsrlN-2k

D_Alex 2 Sep 2015 2:24 UTC
5 points
in reply to: Vaniver’s comment on: Open Thread August 31 - September 6

Despite his frequent comments that he’s “betting” on Trump and that Silver is “betting” against Trump, Adams’s position is that gambling is illegal when pressed to actually bet.

How convenient for him.

D_Alex 1 Sep 2015 6:37 UTC
7 points
in reply to: James_Miller’s comment on: Open Thread August 31 - September 6
Well… Scott Adams has a lot of money. I am willing to bet that Trump will NOT become president, at EVEN ODDS. Scott, if you read this, how about a wager? I propose a $10,000 stake.

D_Alex 6 Aug 2015 8:04 UTC
3 points
in reply to: [deleted]’s comment on: Stupid Questions August 2015
If you are after descriptions of society in those days, try “Quo Vadis” by Henryk Sienkiewicz. Historical fiction about early days of Christianity, won a Nobel Prize for literature. Strong religious themes.

D_Alex 6 Aug 2015 7:51 UTC
1 point
in reply to: Evan_Gaensbauer’s comment on: Stupid Questions August 2015
Or could we breed them for intelligence...? With such short periods between generations, we could reach superintelligence, maybe faster than other methods!

D_Alex 21 Jul 2015 2:44 UTC
6 points
on: List of Fully General Counterarguments
The Big Lebowski: “Yeah, well, you know, that’s just, like, your opinion, man”.

D_Alex 14 Jul 2015 6:14 UTC
8 points
in reply to: bekkerd’s comment on: Open Thread, Jul. 13 - Jul. 19, 2015

What are my options apart from “emigrate and live next to a cryonics facility”?

You could start a cryonics facility in South Africa.

D_Alex 7 Jul 2015 6:57 UTC
3 points
in reply to: James_Miller’s comment on: Open Thread, Jul. 6 - Jul. 12, 2015

Gets a big loan from Russia that prevents an economic collapse (20% likely)

I’ll give 10:1 odds against this happening. Russia has its own economic problems now with the drop in the price of oil and Ukrainian conflict, and other issues… China might be more likely, though IMO both Russia and China are a scare ploy by the Greeks.

A somewhat likely possibility is: Greece leaves the EU, triggering an economic collapse, possibly followed by a political collapse. Then spends many, many years trying to sort out itself and wishing it had stayed.

D_Alex 17 Jun 2015 2:49 UTC
12 points
in reply to: ChristianKl’s comment on: Open Thread, Jun. 15 - Jun. 21, 2015
I am sure that there are many jobs where mental math makes a huge difference.

I manage a team of engineers, and though pretty much all of them are head and shoulders above me in their specialisation, they think I really know my stuff because I find errors in their work and zero-in on them on the fly. The skill that I have is doing rough approximations in my head. Then from experience: a factor-of-two difference is commonly confusing kg and lb, a factor of 10 - confusing kg and N, a factor of fifty—mistaking degrees and radians (usually in Excel, where radians are the default mesurement), etc… I get a LOT of mileage from this :). If they did the same, their already good work would be even better. And I imagine any calculation intensive job (finance, economics, science, business...) is similar.

D_Alex 19 May 2015 0:55 UTC
1 point
in reply to: Lumifer’s comment on: The ganch gamble
“Ganch” was an unknown word for me too, so i googled it and the first link was from Urban Dictionary… I’ll not say what I found, it is inappropriate.

But then I searched some more, quite a lot, until I found this definition, from the Great Soviet Encyclopedia:

Ganch: Middle Asian name for a binding material obtained by heating rock containing gypsum (from 40 to 70 percent) and clay. An aqueous solution of pulverized ganch sets quickly (hardens) and is easy to mold. From the first centuries of the Common Era ganch was used as a material for plaster, volumetrical and plastic decor (carving, casting of lattices and other parts), and sculpture. Wet ganch can be cut easily and allows both bas-relief and high relief to be diverse and have fine details. Carved ganch has a pleasing white mat surface. A layer of slightly wet ganch serves as a base for wall paintings. In the Caucasus it is called gazha.

D_Alex 10 May 2015 6:00 UTC
0 points
in reply to: Alsadius’s comment on: Why capitalism?
I still do not understand your objective in this discussion. It seems that you are implicitly against subsidising renewable energy. Is this correct?

(I work in the oil and gas industry, by the way, so fossil fuel subsidies sort of help me out...).

For that matter, I do not understand the upvotes in this thread. A citation was asked for—then it was provided—and then there are several posts attempting to invalidate the citation, attracting upvotes. Strange.

I want a better source than naked statement of a number from a biased group

We all do… could you please provide one?

if you want me to think that renewables … are a good choice for the US...

I don’t know when this discussion started to be about the US, and I don’t know if I really care enough about what you think to put in more effort… are you in a position to influence what the US chooses? If yes, then I will explain why this statement:

how switching from a cheaper source [presumably fossil fuels] to one that’s more expensive [presumably renewable energy]

is wrong.

D_Alex 8 May 2015 2:27 UTC
12 points
on: California Drought thread
Engineering solutions (RO desalination powered by photovoltaics) exist right now to deliver practically limitless amounts of potable water in a sustainable manner for around $1/m3. That is 1 cent per 10 litre bucket.

I am not sure who is feeling the pain in California… $1/m3 may be too much to pay for broadacre farming. But for city residents, who (in Australia) typically use ~300l/person/day, including lawn care, this seems very affordable.

Incidentally: Perth, Australia, used to rely on dams and groundwater to supply its needs. When I visited the dams 10 years ago they looked about what Californian dams look like now. This year, the dams are nearly full, and the annoying ads urging reduced water consumption have disappeared. What has changed? Two RO desalination plants were built, and now roughly half of Perth’s fresh water supply comes from these plants. To power the plants, two small-ish wind energy farms have been built. So perhaps this is the right solution for California also...?

D_Alex 6 May 2015 3:32 UTC
0 points
in reply to: Lumifer’s comment on: Why capitalism?

cool toys and I’ve been tempted to get one a few times

If you can use a 3D design program like Google Sketchup—do it! It is a cool toy, it is at least of minor practical use, and you might catch a wave to the future.

Saving money on a 50-cent bracket via buying a $1,000 printer doesn’t look particularly rational to me

Naturally. But throwing away a $1000 item for the lack of some stupid bracket that should cost 50 cents but can’t be had for any money AFAICT is not great either...

D_Alex 6 May 2015 3:22 UTC
2 points
in reply to: Alsadius’s comment on: Why capitalism?

Remember, a lot of renewables get thrown in together without being the same. The renewables that get subsidies are mostly the flashy new ones...

I have provided a few facts… you are trying to put a certain interpretation on them. To what end? What is it exactly that you are trying to argue?

Seriously? 80% of the money spent on anything being non-OECD is hard to fathom...

And now you are denying the data.

What is subsidised and where, is decided by factors that are not necessarily obvious or “sensible”, and there is a huge element of political electability. In OECD, fuels are a source of taxation revenue, whereas farmers, for example, benefit from subsidies. In the middle east and South-East Asia, fossil fuel is heavily subsidised, eg. in Indonesia gasoline sold for about 90% of crude oil price while I was there (and Indonesia imports their crude). I read that fully half of government revenue was at one point used to pay for the fuel subsidies. Why? Well, as soon as there is a discussion of reducing the subsidies, protests break out, and the politicians supporting the reductions do not get re-elected....

D_Alex 5 May 2015 2:54 UTC
3 points
in reply to: Lumifer’s comment on: Why capitalism?
I have a 3D printer (Makerbot 2, not really low end, cost ~$2000), so let me correct a couple of misconceptions in this thread:
1. 3D printed parts can be, and usually are, quite strong. The strength of a part is directional—the parts are much stronger in the direction parallel to the filament deposition than in the perpendicular direction. But door handles and the like are no problem at all. The parts can also be strong and very light, because printing the inside volume as a honeycomb mesh is possible (and is the default option at least on the printer driver I am using)
2. The labout input in actually making a part is minimal, surely less than a trip to the store to buy one. Currently, the labour-intensive part is finding or producing the right design—but once the design is made, it can in theory be available to anyone in the world to use. “Thingiverse” is an attempt to collate the various designs, unfortunately it is full of sub-mediocre stuff and not sufficiently easy to navigate around.
I have literally hundreds of 3D printed objects around me right now, most are models of industrial plants and boats. But I have also made a few everyday objects that I otherwise would have had trouble getting at all, including:
- A control knob for my amplifier, the original was lost somewhere
- A knob for window wiper control for my car
- The little thing that you pull to open the door in the car
- A hard-to-explain bracket that holds a milk shelf in my fridge
Now that i have made the models (and it was fun to do, so was there a labour “cost”?), these things above should be available on the ’net for anyone… I feel kinda bad for not doing that, but the problem is this: How do I identify say the fridge bracket, so that people can find it? OK, its a Fisher and Paykel 350 l fridge, model ABC-1234 or w/e, but then...? Now if the fridge maker provided the design on their web site, we’d be getting somewhere, and if 3D printers have sufficient penetration, perhaps they will one day.

D_Alex 5 May 2015 2:26 UTC
0 points
in reply to: Alsadius’s comment on: Why capitalism?

But renewables are vastly smaller than fossil fuels

Not really. From http://en.wikipedia.org/wiki/Renewable_energy :

“Based on REN21′s 2014 report, renewables contributed 19 percent to our energy consumption and 22 percent to our electricity generation in 2012 and 2013, respectively”

So if you believe Wikipedia (and is there a better general source?), fossil fuels attract more subsidies per unit energy as well as in total.

D_Alex 4 May 2015 7:55 UTC
5 points
in reply to: ChristianKl’s comment on: Stupid Questions May 2015
Yes, there is.

http://en.wikipedia.org/wiki/Lithium#Terrestrial gives reserves of 13 million tonnes, ie 13 billion kg. I think these are “proven” reserves, ie economical to mine at current prices.

The amount of lithium in a Li-ion battery is not that much, roughly 500g/kwhr. So a 10 kW Tesla Power Wall would contain about 5 kg of lithium. We can make 2.6 billion Power Walls… and E. Musk said at the launch that 2 billion would be enough to convert the entire planet’s energy usage—including industry and transport—to renewable electricity.

D_Alex 4 May 2015 7:21 UTC
1 point
in reply to: ChristianKl’s comment on: Stupid Questions May 2015
Yep… take a look at this, one of the largest solar PV plants in the world:

https://www.google.com/maps/search/35.383333,-120.066667/@35.383333,-120.066667,12z/data=!3m1!1e3!4m2!2m1!4b1?hl=en&dg=dbrw&newdg=1

It supplies but ~1% of electric power for Los Angeles… However zoom until you can see Los Angeles itself, a little to the southeast.