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Comment Re:Waste of helium (Score 1) 189

this is a portable aircraft with a good carry capacity.

The new version of the Russian Mi-26 heavy-lift helicopter can, reportedly, lift 25 tonnes, significantly more than the Airlander. Existing models of the Mi-26 can carry 20 tonnes of cargo, land on large ships, don't need lots of prepared ground to operate from etc. There's talk of an evolutionary new version to be developed jointly by Russia and China which would be able to lift 33 tonnes but it's still on the drawing board.

The Airlander folks have glossy brochures extolling later development versions of their airship which reputedly would be able to carry up to 60 tonnes of cargo but it's taken them all this time to get their first prototype into the air. I wouldn't hold my breath waiting for that larger version to make its first flight.

Comment Re:Salesmanship (Score 2) 343

Yes, longer-wavelength radars can indeed detect stealthy aircraft. Warships with sea-sweeping radars can often spot such aircraft. The problem is they can't hand off an accurate location and track to the anti-aircraft missile radars which need to be much higher frequency to determine the aircraft's position to within a few centimetres so they can actually hit it. Those missile system radars are what the stealth profiles and skin coatings are designed to be near-invisible to and they do that job very well. At the same time active radars are a perfect target for anti-radar missiles of the sort the F-35 carries among other payloads. In addition it can network its own radar detection systems, handing off radar targets to other aircraft such as the F-14 which can't approach a defence area too closely because they would be detected and fired upon.

Comment Re:Math Doesn't Add Up (Score 1) 144

Combined-cycle gas turbines (CCGTs) can reach 60% efficiency but they're more complicated than a simple once-through gas turbine of the sort that's likely to be fitted to a truck like this. CCGT power plants boil water to steam with the turbine exhaust and use a secondary steam turbine to generate more electricity hence the 60% figure but they are bigger, heavier and more complex than any conceivable mobile power plant.

Comment Re:Math doesn't work out (Score 1) 1023

Some Lidl stores do have self-checkouts. I was in one today and used a self-checkout there. However the Lidl store I go to most often doesn't have self checkouts and I can spend more time waiting in the queue for a manual checkout than I did shopping for the half-dozen or so items I usually buy. The till operators are pretty quick but there are never enough of them on duty to save on overheads and the store is always busy because of the low prices.

Comment Numbers (Score 1) 324

A thousand tonne train of railcars pulled up a slope 100 metres in height, assuming no losses (spherical cow assumptions here but bear with me) will require Mass x Gravity x Height = 1 billion joules = 270 kWhr which at commercial rates for electricity is worth maybe $20 or $30 US. That's not a lot of energy storage given the capital cost of track and equipment and recurring maintenance costs etc.

Comment Re:We know what the next innovation is. (Score 1) 225

The big problem with iCar is that obeying the Holy Jobs design rules there will be no holes in the bodyshell large enough for people to get in and out. The solution (so to speak) to this will be the iChipper(tm) with a flexible hose and a unique patented nozzle coupling in the side of the iCar. It will require an up-to-date version of iTunes to get back out of iCar.

Comment Re:May not continue for the long-term (Score 1) 314

Solar thermal involves storing heat in something like a molten salt tank and releasing that heat later to generate electricity when the sun is down. This wastes energy -- direct use of the heat would produce more electricity in total over a day cycle but peaking over a shorter period of time.

Most of the solar thermal plants that have been constructed to date use thousands of heliostat mirrors to concentrated light on a tower-mounted heat store. The tower has to be very strong to carry the mass of the heat store and the heliostats move in both X and Y to track the sun, eating energy and breaking down. Simpler non-storing solar thermal plants are cheaper to build and operate, typically using fixed mirror troughs and heat transfer pipes to collect heat for steam turbines.

As for moving to 100% electric cars, nations that do so will need electricity to charge them and that's probably why China and India are building lots more coal-fired power stations. Assuming they can source coal locally or at low cost from places like Australia it saves them buying as much oil as they do today so it's a win-win. The new coal plants will probably have modern stack filtration so they won't be quite as toxic as the old plants but they'll still not be very "green" and of course they will emit large amounts of fossil-fuel-derived CO2.

Comment Re:Lee Se-dol also learns (Score 1) 109

There are only a few hundred records of games played by Lee Sedol and only a few dozen of them were championship games lasting several hours or even a couple of days like the AlphaGo series. The playing style of these longer games is different to the shorter games played against lower-ranked players or for tuition or study.

The DeepMind people have stated clearly that AlphaGo has NOT been prepped with games by Lee Sedol. I don't know if the reverse is true but it's common for Go players facing a particular opponent, especially in a series, to study some or all of their game records.

Comment Re:Terrorist Disables Mobile Phones On Chicago Bus (Score 2) 518

I work alongside someone who has permission to keep his mobile phone on his desk in an office which is otherwise meant to be a no-mobile zone. He's waiting for a transplant and if an organ match comes available he needs to know right away so he can get to the hospital and start getting prepped for the operation immediately. Someone using a jammer for their convenience could result in him dying before he can get treated.

Comment Re:Obligatory.. (Score 1) 90

One of the weapon systems in the US military Bag of Holding drops strings of conductive carbon fibres over electrical switching stations and generating plants to blow them out. It was used during the initial attack on Iraq in 2003, deployed by cruise missiles IIRC. There may also be a precision free-fall bomb that can do the same thing.

Comment Re:32inch 4K monitors not ready for prime time yet (Score 1) 156

I've been using a Dell 32" 4k display for about 15 months now, running it at 60Hz over DisplayPort from a budget AMD video card, the cheapest I could buy at the time that had DP output. I don't game on this monitor, other than Spider and the occasional sudoku puzzle.

I used the DP cable supplied by Dell with the montor (UP3214Q) and it's worked perfectly although it took a little time to set it up and get it to run at 60Hz since it defaulted to 30Hz out of the box for compatibility reasons. No backlight bleed that I can see.

Comment Re:Multiple heads (Score 4, Informative) 202

There were SCSI drives with four head actuators, one in each corner of the drive casing. They were treated as four separate drives logically and used to speed up reads on a "first to deliver the requested block" basis. They were horrendously expensive and it turned out to be very difficult to optimise the read process to gain the desired perfomance boost.

Comment Re:Langley (Score 1) 53

The light from the two scopes has to be combined optically though. The phase information is crucial (the two mirrors have to be aligned to a fraction of a wavelength of light).

That's not totally correct; if the processing system knows what the alignment error is at any time it can correct the image data collected, it doesn't have to have the mirrors in "perfect" mechanical alignment at all times. It's not a trivial thing to do but it's feasible. It recovers resolution at the expense of light grasp and that is a tradeoff that might be worth paying in some cases.

Comment Re:Langley (Score 3, Interesting) 53

One problem with the large-mirror spy satellites is that they can only look at one place on the ground in detail in a single pass since they only carry one large mirror. I suspect modern spy satellites carry multiple independently-targettable imaging systems with the ability to digitally combine images for higher resolution where needed on a case-by-case basis. This is similar to the way the largest land-based astronomical telescopes are now all multiple-mirror designs but without the requirement for on-the-fly reconfiguration during observation campaigns.

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