Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).


Comment: Re:if it doesnt work (Score 2) 464

by voidptr (#48719241) Attached to: Ask Slashdot: Are Progressive Glasses a Mistake For Computer Users?

And unlike bifocals/progressive-lens glasses, you can't really orient contacts so that a region with different correction is at the bottom.

I don't use them specifically and couldn't tell the OP if they would help their specific situation, but there are bifocal contacts on the market now. I do use toric astigmatism lenses in one eye which are similar, they're designed in a way that causes them to settle into a certain "up" and "down" orientation when installed.

Comment: Re:First 'conjoined' satellites? (Score 3, Informative) 67

by voidptr (#48388025) Attached to: Boeing Readies For First Ever Conjoined Satellite Launch


Or the Orbcomm OG2 constellation that went up in July...

Launching multiple payloads on a single launch isn't exactly new. It sounds like the innovation here is using the satellites themselves as load structures for each other during launch rather than something like an ESPA ring to save weight and payload volume, but launching more than one satellite per mission is pretty common.

Comment: Re:Why so much fuss? (Score 4, Informative) 156

by voidptr (#47944305) Attached to: Dealership Commentator: Tesla's Going To Win In Every State

That's a reason why you should protect dealer networks if a company decides to start with that business model.

That's not a reason to protect those dealer networks from an upstart company that never had that business model. Just because GM and Ford made a deal with the devil 50 years ago shouldn't bind a new company to that same business model. Tesla has never had a dealer franchise agreement with anyone, them selling directly does not break any contractual agreement they've entered in to. They have no obligation to respect an agreement Ford or GM made with their dealer network to not compete.

Also as a counter point, Apple sells plenty of things through the half dozen Best Buys in my town. There's also two Apple stores within a 20 minutes drive. Just because a company sells through channel partners doesn't immediately preclude them from selling direct, it depends on the agreement they made with the channel in the first place. Even car dealer arrangements started out with the dealers protected by the franchise agreements themselves, elevating them from simple contract law to specific legislative protections came later.

Comment: Re:Spot on (Score 4, Insightful) 156

by voidptr (#47944295) Attached to: Dealership Commentator: Tesla's Going To Win In Every State

In many cases they're specifically prohibited from opening one. Cars must be sold through dealers, and dealers must have an arms-length relationship with the manufacturer and can not simply be the manufacturer or a subsidiary of the manufacturer.

Those laws were basically written because while franchise agreements between dealers and manufacturers protected the dealers from direct manufacturer competition, the dealers believed they weren't strong enough and eventually manufacturers and their brands would become strong enough that manufacturers would find a way around them, or simply wait for the agreement to lapse and refuse to renew with that term, that dealers got them codified into law.

Which puts us back to the original point. The law was intended to protect existing franchises from existing dealers. They never anticipated a new manufacturer showing up who didn't want to sell through dealers. The law should not bind Tesla or any other new manufacturer to a business model GM and Ford designed many decades ago that puts the new entrant at a competitive disadvantage.

Comment: Re:"An anonymous reader" (Score 2) 112

by voidptr (#47451607) Attached to: SpaceX Falcon 9 Rocket Blasts Off From Florida

There was only 1 loss on ascent and 1 loss on decent with too few flights to show if those single losses had a probability of greater than 1 in 500.

Columbia was doomed by the time it finished ascent, it just took until descent for the scope of the damage to become apparent. Arguably both losses in the shuttle program can be considered "on ascent".

Comment: Re:I wish them well (Score 2) 146

by voidptr (#47388155) Attached to: NASA Approves Production of Most Powerful Rocket Ever

I think it's more the fact that the whole program feels like it is being stitched together based on which existing technologies and contractors contribute to which congressional seats, rather than which technologies are really a good fit in the long term. As well as the fact that beyond a fairly nebulous manned astroid-capture mission, there doesn't seem to be any great plan or will to have a concrete goal for the booster in general. If Congress earmarked $50B over the next decade to put a research station on the Moon or Mars and insulated it from the year-to-year whims that always infect NASA's budget process it'd be one thing, but they aren't. They're trying to build a rocket and then hope two administrations from now it gets a mission funded.

On the technical side, any believe there's no place for solid motors on crewed flight anymore except to ensure campaign donations from Thiokol and United Space Boosters.

Second, while waiting for the new SSME derivative to get finalized and into production, they intend to fly the existing engine inventory. As one of the larger flown relics from the shuttle program, and with several dozen laying around, many of us would rather see them distributed to smaller museums that didn't get orbiters instead of splashed in the ocean. And as a result of the decision to use up the existing stock, the entire expendable stack is built around an engine that's was originally designed for reusability, with all the cost and engineering penalties that implies, and is ultimately too small for the job anyway. If you don't try to fly the existing SSME stock, something like a larger, more modern F1 derivative may start to make more sense, enabling a more powerful liquid first stage without having to bolt solids on the sides to get it off the pad.

Comment: Re:what happens if the chick get pregnant? (Score 2) 240

by voidptr (#44536629) Attached to: One-Way Ticket: Mars One Project Applicants Top 100,000

Fun fact: having a child on Earth also means inflicting an uncertain existence upon them including certain death. That fact doesn't appear to have stopped significant numbers of earthers from breeding either, even in conditions most of us wouldn't want to spend a day in let alone a lifetime.

Comment: Re:Efficient-market, inefficient-energy hypothesis (Score 1) 775

by voidptr (#44166081) Attached to: Electric Vehicles Might Not Benefit the Environment After All

By your theory, my Model S wins. The initial purchase price of a Model S is pretty middle of the pack to comparable cars in the full size luxury sedan class.

Similarly sized and spec'd ICE vehicles to the Model S get 20 - 25 MPG. At $3.50/gallon gas, that's 14c/mile.

The Model S gets about 3 miles / kWh. At 11.5c/kWh, that's 3.8c/mile.

Even if we assume a kWh from gasoline and a kWh from the wall have similar environmental impacts, and transmission costs/losses for both are properly reflected in the price at the meter, the Model S is three and a half times more efficient at turning the delivered energy into motion.

Comment: Re:Let's compare the two (Score 1) 559

by voidptr (#43880391) Attached to: No, the Tesla Model S Doesn't Pollute More Than an SUV

You're the one who started with the statement you could power a gasoline engine with a renewable clean energy source, namely Hydrogen.

You can't. Hydrogen isn't an energy source, because you can't refine hydrogen into a viable fuel using just hydrogen feedstock in an energy positive process. Hydrogen/Oxygen is at best another energy storage media, with cycle losses and storage requirements that are distinctly different but not theromdynamically unlike existing battery chemistries. There's nothing "clean" or "renewable" about burning hydrogen in an ICE engine in and of itself.

Comment: Re:Let's compare the two (Score 2) 559

by voidptr (#43878811) Attached to: No, the Tesla Model S Doesn't Pollute More Than an SUV

The point is, hydrogen isn't any more of a fuel than lithium in a battery is. They're both just energy storage media.

Gasoline is a fuel, because I can take a barrel of oil out of the ground, consume some of it to repay the energy used to pump it out, consume some of it to refine the remainder into gasoline, and end up getting more energy out of burning the rest than I had at the beginning of the process.

There's no above-unity mechanism to get free hydrogen into a motor vehicle, certainly not one that works on any commercial scale.

When you don't know what to do, walk fast and look worried.