Please create an account to participate in the Slashdot moderation system


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:No they don't (Score 1) 215

by OzPeter (#49369883) Attached to: Chinese Scientists Plan Solar Power Station In Space

This stupid idea gets floated every few years. It doesn't work, even in theory. Do the math yourself.

I just took a look at that site, and while in general I agree with his conclusions, I am perplexed by some of the math that he uses.

For example I do not see why Tg is different for ground based versus space based systems, and why it so not eliminated as per the E term (and why is Tg higher for a space based system?). And the links he supplied for the lifetime of space based cells are frankly puzzling to me as I cannot see anything in them that backs up his assertions (which is different from saying his assertions are false).

In addition while a space based system has issues with transmission and degradation, he leaves out the fact that a space based PV system operates 24/7 with continuous output compared to an earth based system that has to deal with the vagaries of weather and that pesky thing called "night". Thus an Earth based PV system will always have to have additional non-PV infrastructure in order to deliver comparable energy delivery. So that will also change the overall economics.

Comment: Re:Wrong Focus (Score 2) 121

by OzPeter (#49364865) Attached to: SpaceX's New Combustion Technologies

Don't forget the multi-megawatt radiators needed to provide a cold sink for those reactors. Chemical rocket engines dump heat into the exhaust gases but in a vacuum radiators have to be huge and heavy to get rid of significant amounts of heat from something like a nuclear reactor. They also have to be shaded from sunlight to stop them absorbing heat...

There is always Nuclear Thermal Rockets which pour the reactors heat into the propellant.

Comment: Re:How is it a "rite of passage"? (Score 4, Insightful) 49

by OzPeter (#49361287) Attached to: Startups Increasingly Targeted With Hacks

They're getting cracked because they're not paying attention to their security.

But start-ups are all about the most buzz you can generate in the shortest time. You need to get that product out the door ASAP because your competitors aren't going to wait for you to build your secure system first. After all, you're not in the business of security, you're in the business of connecting up the most people and building your community. /sacasm*

*Added because even I thought I was starting to sound like a lean-startup advocate

Comment: Re:Don't make it impossible, just make it hard (Score 1) 378

by OzPeter (#49355891) Attached to: Modern Cockpits: Harder To Invade But Easier To Lock Up

If a two-person rule is put into place, also put into place two switches further apart than arm's reach that have to be pressed in-sync or in very close succession.

So the pilot and co-pilot are in the cockpit and the door is locked. Then one of them has a heart attack and is incapacitated. Now no-one can get into the cockpit.

Comment: Re:Risk Management (Score 5, Insightful) 736

by OzPeter (#49344243) Attached to: Germanwings Plane Crash Was No Accident

Regardless, was 16 schoolkids (amongst others) on that flight. You wanna hari kari? Go ahead, but keep it on your own dime.

Invoking "Think of the children" is just as bad here as anywhere else. None of the people on that plane deserved what happened to them*

  * with perhaps the exception of the co-pilot

Comment: Re:Economics (Score 2) 148

by OzPeter (#49339879) Attached to: First Nuclear Power Plant Planned In Jordan

Could someone fill me in on the economics of nuclear power generation? I'd like to know what the usual payback period for a plant is, and how much it costs to operate a plant over that period.

Well in terms of foreign aid and keeping a positive political presence in the area, the payback for Russia is priceless.

[Crash programs] fail because they are based on the theory that, with nine women pregnant, you can get a baby a month. -- Wernher von Braun