Because it comes in at a different frequency versus when it goes out. Light, including UV and visible light, hits the ground, then the ground gets warm and radiates in the IR, which can be blocked by clouds.
Perovskites break down when exposed to moisture, so while I do think you could DIY a solar cell pretty easily, it wouldn't last long. There are ways around the moisture problem, but they're not so easily DIYable. "In particular, water promotes fast decomposition, leading to a drastic decrease in device performance." [0]
Sorry for the paywall, but I was reminded of this article in the Economist about the popularity of the Toyota Prius in Mongolia. One reason is low prices, but another is that they will start in extreme cold when ICE engines can't: https://www.economist.com/asia/2018/12/22/everyone-in-mongol...
Fair enough. I'm sure some would be willing to do that, but likely not many. I do think it is going to be very interesting to work out some of the scenarios if we do get to Johnny Cab style self driving cars.
"By working with the police department in Chandler, AZ, for example, Waymo has been able to train its cars to yield, pull over, or stop when it hears or sees sirens." [1]
By what mechanism though? I could see a big griefing opportunity if there is some automated system that allows law enforcement to signal the vehicle to pull over.
Instead of recognizing the lights or something you could create a communication of some sort where the officer's vehicle provides a key that the car can then authenticate that it's a real police officer making the pull over request.
Heck you could even check with a police department system that the officer is on duty and in that area so a stolen police car or key couldn't be used.
Check out waymo's videos; the car detects the flashing lights + reflective fabric on the police officer's uniform, as well as the shoulder and arm gestures. Griefing is as much an issue as is police impersonation right now, that is a very rare occurence that will be punished very severely when occurring.
Have a look[1]. Observe how they all kind of look like each other regardless of the country: shoulder pads, head cover, belt, uniform colour, formal attire, etc. Once the model knows the baseline, that is "a uniformed individual waving characteristically in front of the car", don't you think it would be quite easy to teach it with a mere few hundred pictures how local police officers look like in the current region?
They don't look remotely similar to me, especially considering that black, blue, navy, grey and khaki (and reflective yellow for people on roads) are not unpopular colours for clothes worn by people who are not police officers or otherwise involved in traffic direction, many of whom may have cause to move their arms in ways comparable to signals. Humans are just a lot better at gauging intention and even simple stuff like parsing the word "police" at an oblique angle
Frankly even with local training, you'd still think giving law enforcement devices to stop, restart and redirect vehicles was a minimum requirement.
All of these agents follow a similar pattern of clothing (as I said, combination of similar garnments and colours) and behaviour (placement on the road, gesturing with authority, directly facing the car, etc.). Machine learning algorithms are especially good at recognizing patterns and storing their abstracted form, so it should come as no surprise that understanding what a police officer looks like in abstract is not the main issue of self driving.
> Humans are just a lot better at gauging intention and even simple stuff like parsing the word "police" at an oblique angle
Google seems to understand these intentions well enough, and at a much higher level than mere word parsing. This video is from 2015: https://youtu.be/tiwVMrTLUWg?t=9m5s
You got the car understanding all that happens at a complex intersection at 9'05, understanding what a police car looks like at 9'35, then detecting and reacting to a schoolbus and then parsing a police officer gestures right at the 10' mark. I'd say chances are these are pretty solved situations 3 years later. You can even see some creatures from their "zoo" of patterns for cars & people at 10'35.
> "When a Waymo car hears sirens, it will automatically pull over, yield, and stop. For example, when a number of vehicles are moving towards the scene of an accident on a highway and ambulances and other emergency vehicles are headed toward it, driverless cars will move aside and give way. Using audio sensors, the cars can detect exactly which direction the sirens are coming from and move out of the way."
> All of these agents follow a similar pattern of clothing (as I said, combination of similar garnments and colours) and behaviour (placement on the road, gesturing with authority, directly facing the car, etc.)
Repeating an assertion does not make it cease to be false. A very small handful of pictures you linked to shows a wide variety of coats, vests and shirts of many different colours, all of which heavily overlap with general garment types and colours used in everyday clothing which tend to indicate police only with small and greatly varying trim detailing (and sometimes hats). And is the clothing and trim designed to convey authority? isn't the sort of abstract pattern recognition computers do better than humans, or even at all well. Sure, you could certainly create specific police uniform training sets for every jurisdiction and possibly even cut down false positives in other jurisdictions by geofencing them (so you don't get people stopping in California for commuters wearing the distinctive er... blue shirts and black trousers of the Hong Kong police) but it's a non-trivial undertaking even if there are bigger problems for SDVs to tackle
More importantly, unlike humans evolved to have an intimate understanding of human mannerisms, machine learning has no concept of "gesturing with authority", beyond whether moving human shapes fit very specific patterns within its calibration parameters, and police officers often don't have scope to place themselves in a particular position in order to get the car to understand them.
> Google seems to understand these intentions well enough, and at a much higher level than mere word parsing.
The video shows examples of predicting possible directions of travel of moving road users based on maps and movements (i.e. its fundamental driving model) and a shot of it recognising two arm gestures in an idealised front on positions. Neither fall under the scope of being able to understand how the traffic policemen intends to clear the blocked intersection from his shouts and gesticulations at you and various other vehicles. Humans also don't need to be signalled to go again if the black-jacketed man they've stopped for was actually trying to hail the taxi behind them.
I think you make a good point, but there's a big difference between the amount of waste produced and the amount of waste that makes it into the natural environment, as opposed to a recycling center or dedicated landfill. Just because developed countries are producing more waste does not mean that they are contributing more waste to the bottom of the ocean. (I am not suggesting that we should not all aim to produce less waste and handle what waste we do produce better.)
The point is that a large amount of waste produced by developed is dumped/exported to developing countries like China, India, Bangladesh and Vietnam. And a large amount of waste generated by these countries is done so in the production of goods meant for Western consumption.
>a large amount of waste generated by these countries is done so in the production of goods meant for Western consumption.
Why does this matter? A factory polluting local lakes and rivers to make goods for export to another state definitely couldn't use this as an excuse. They control the process, so they are responsible for consequences of using that process. So why rules are suddenly different when we talk about countries?
Because we’ve exported our externalities. Global industry doesn’t choose to manufacture in China because of the great views. Their regulations are effectively non-existent. Those regulations in the West protecting the environment, the community, the workers etc? They have a cost that many consumers are unprepared to bear.
Perhaps advocate for changes in the rules, whether that be directly or indirectly (e.g. by supporting propositions that mandate better supply-chain/whole-product-lifecycle accountability). Perhaps make choices that preference those companies with better lifecycle/supply-chains (and if you can't tell which those are, then perhaps advocate for changes in transparency regarding those things).
Change is slow and hard. Throwing up our hands and carrying on with the status quo is a choice not an inevitability. If we each live our lives according to the world we want to live in, and make our personal choices accordingly, then at the very least we'll be able to tell our kids we tried.
The article points out that 89% of sea plastic is the throwaway kind, e.g. cutlery and plastic bottles. It's relatively simple to cut down on these. Switch to using aluminium cans instead of plastic bottles, they're much more likely to be recycled. Then obviously put the can in the recycling. Better yet, use your own water bottle. If you want bottled water get it in crates of glass bottles. Shops will often take the crates back to be washed and reused.
But isn’t most of the sea plastic also from the Yangtze and Ganges rivers?
I try and avoid single use plastic, it seems obscene to me it even exists, but my waste ends up in landfill. To solve ocean plastic we need bin men and landfill in the countries causing it.
The fight against single use plastic in the developed world is just, but a separate issue.
A problem in the UK has been that plastics have been passed on for recycling only to be sent to China, for example, and dumped.
The issue as I see it is that we expect waste processing to be profitable and only do it if it is - waste processing should be handled from the profits of waste production.
So many companies conning their customers with half-empty packaging, products designed to break, etc., seems to be a large part of the problem.
I think it's become apparent that in pretty much every western country we were shipping them to China, as you described for the UK. That's now come to an end. Who DOES subsidise local industry enough to recycle in-country?
The main thing that needs to happen is the creation of a strong enough political consensus to force a strong limit to the production of unnecessary plastic objects as well as forcing proper disposal of the objects that are produced. This is would require international cooperation.
Obviously, this is far from where the world seems to be heading currently but it's still the only way.
No you can't do that either. If you are old enough to remember the 80's and 90's, these same people that are whining about plastic now are the ones that forced us to use it because paper bags were killing the trees. Oh fun fact they are also the ones that brought us trans fats as a "safe alternative" to using animal fat.
Hmm, the problem was not that paper bags inherently kill trees, it was that virgin forest was being destroyed and not replanted in order to make paper products. So the obvious solution of using sustainable forest growth and recycling was rejected (however, maybe by "The Market" - aka refusing to accept responsibility for externalities) presumably because plastics were marginally cheaper.
Market forces just don't work for these things because the negative consequences are decades away and don't necessarily affect the producers/consumers at all.
Your position that people who didn't want rainforest destroying for one-time use bags are responsible for one-time use plastics is way off the mark. Such people use reusable bags from sustainable sources invariably, for example.
When these issues hit the mainstream, and the public don't fully understand the position, then it's easy for the Capitalists to shift to the 'next-worst most profitable' thing rather than shifting to a sustainable production.
You can change what you purchase. Don't but so much temporary plastic, look for alternatives. Shop at markets where they don't wrap everything in plastic.
The mental acrobatics some people will do to fan the flames of western guilt is incredible. Ignoring the fact that the Asian market is massive, the fact that things are intended for western consumption doesn't mean westerners are somehow complicit in the pollution caused to make them.
I don't think Western-exported goods contribute massively to pollution in Asia. Local consumption drives most of it. You can't really blame disposable chopsticks or plastic bags in the Yellow River on Western consumers.
That being said, I disagree with the spirit of your comment. When ABC corp relocated to underdeveloped country so they can avoid regulatory burden (be it pollution, or labor laws), the end goal is to achieve competitive product pricing back home. A portion of the $$ they save in Asia is passed down to the Western consumer.
Whether you want to feel guilty about it ("they only make 50 cents an hour making my Nikes, outrageous!"), or proud ("they make a whole 50 cents thanks to me!") is up to you I guess, but the link is there.
You have hit the crux of the matter, it's almost entirely outside our control at the local level. Not using plastic as much has no effect on whether or not an Asian man throws his garbage in the river in China, or if the company contracted to deal with the waste does, but lies about it to us.
What you are proposing ends up as "don't do business with Asian countries because they can't be trusted to deal with the trash properly."
It's really easy to find photos of waterways all over the world, and it's abundantly clear which countries and cultures value clean water ways over cost/time to deal with the garbage. Where it comes from seems to be irrelevant.
I think all cultures value nature to one degree or another. Once developing countries accrete enough wealth, they will probably invest some of it into proper waste disposal. It's hard to justify diverting resources into waste disposal now, when you are still poor and hungry and in the midst of industrialization.
Western societies went through the same process. They polluted heavily through much of the XX century, while building up their own industrial economies, and didn't start cleaning up until the 1970s and 80s.
I am hopeful developing countries follow the same trajectory. China, for example, has been successful at tackling its air pollution. And googling shows that they began rolling out programs to combat river pollution as well. Eventually, we'll get there. Not soon, but eventually.
Seriously. The countries with terrible work conditions and poor records with humanitarian rights could care less about pumping trash into the ocean? That should shock nobody. Who are these apologists?
If your flight time is half, you can run twice as many flights per day with the same plane, which halves your amortized capital cost per flight. That doesn't get you all the way there, but it's a significant cost reduction, which combined with others, could conceivably get you there.
> If your flight time is half, you can run twice as many flights per day with the same plane
Certainly not. Planes don't spend all their time flying. A significant part of the time they are being boarded or people are stepping out, and freight is being loaded and unloaded, and the plane is service, fuel tanks are filled, catering material brought in, wings are de-iced. Some of these activities happen at the same time with each other, but many of them not.
Planes don't spend all their time flying. A significant part of the time they are being boarded or people are stepping out, and freight is being loaded and unloaded, and the plane is service, fuel tanks are filled, catering material brought in, wings are de-iced.
The turnaround time -- time needed for everything that happens from when the plane arrives at the gate to when it departs again -- is only comparable to flying time for smaller aircraft doing shorter domestic hops.
For aircraft doing the kinds of inter-continental segments a supersonic airliner is targeting, there's no real comparison. And airlines most certainly do optimize for time spent in the air; a plane on the ground is a plane making no money. So you see a single aircraft bounce around among a bunch of hubs all in one day, for example, or larger, longer-range aircraft doing rotations of where they fly to (like having the same aircraft do a flight from the US to South America and back, then off to Asia and back, to optimize for arrival/departure times and minimize time spent not flying)
Of course airlines optimize it, but still, boarding alone takes a significant portion of the total time needed for a long-haul flight.
If I look at the latest long-haul flight I took, the flight time was 11 hours, turn-around time at airport 4 hours, for a total of 15 hours. If you'd drop the flight time to half, and manage to do accelerate boarding, cleaning, re-fueling etc in 3 hours, you'd come up with 8.5 hours. Much better, but not even close to be able to deliver twice as many flights per day. It'd be more like a 50 % improvement.
Long-haul utilization also depends on one other factor, which is time zones. It can be worth leaving the plane on the ground longer in order to line up for a more desirable departure/arrival time.
You see this a lot with transatlantic flights, where they spend more time than necessary on the ground at each end, but doing so sets up better timing (like eastbound TATL flights departing in North American evening and arriving in European morning).
Those are marginal costs. Parent comment was talking about amortised costs, i.e. fixed costs. Such as the airplane, itself (depreciation per mile of flight aside, but that’s another point).
IIRC lifetime ratings on aircraft are most heavily based on the number of pressure cycles the airframe receives, i.e. the number of flights it does, not the length of time it spends in the air or its age. So being able to do twice as many flights in the same time just shortens the lifetime of the aircraft.
Actually, we have some very advanced materials which I know from personal experience can hold concentrated sulphuric acid for years! Here is an example of a container made from this amazing material: https://www.restauro-online.com/Sulphuric-acid-95-97-pa-Reag...
