Please create an account to participate in the Slashdot moderation system


Forgot your password?

Comment Re:In other news... (Score 1) 483 483

> hmmm... I can only speak to what I've heard of the US grid

Which is, apparently, "nothing whatsoever".

> You have to use oil if you do that ::rolleyes::

Hydro has the fastest ramp time of any power source, followed by the *infantismal* amount of ICE engines, followed by natural gas turbines.

> Yes you know it will be a sunny day or there might be wind but you really don't know how much.

We know within something like 20% what will be going on in an hour to four. This has been the case for the better part of a decade now (I was doing tech analisys on energy systems when this stuff went mainstream). There is more than enough warning, what MAY be lacking is the NG peakers to offset it. At current levels, however, this is a total non-problem.

> Login and make your point or remain an ignorable AC troll. ;)

Says the guy with an alias.

Comment Re:What are they going to replace with? (Score 1) 483 483

> Without drastic reduction on the demand side

I lived in Ireland for a while. One day in October when it was nasty outside I was inside shivering and then noticed why... the drapes were blowing around. So I got up to close the window.

The window *was* closed.

This was in a home built in the 1970s.

In contrast, I am now living in a typical Canadian home built in 1972. It is completely insulated, plastic wrapped and has reasonably high-quality double-pane windows throughout. The only thing that's changed since is to use more insulation overall and to also cover the outside of the basement walls, which they didn't really start doing around here until the 90s.

Even still, it uses much more energy than it has to. I've already replaced all the lights with LED and put in reasonably new appliances, so my daily electricity is down to about 10 to 11 kWh, about half the national average. Most of the energy I use is heating, and I could cut that by 1/2 to 1/3rd by using a georeturn heat pump.

Cutting total energy use in half in the western world is not impossible. Just expensive. But we're talking "about the same as that craptastic Wolf stove and terribly inefficient Sub-Zero fridge" expensive.

Comment Twaddle (Score 1) 158 158

The summary here on /. reads

"After taking control of the car's entertainment system it was possible to gain control of vital car systems such as the brakes"

Actually reading the article you find nothing of the sort happened. The article merely states

"Once an infotainment system had been compromised, he said, an attacker could potentially use it as a way to control more critical systems, including steering and braking."

This hack consisted solely of causing text like "LOLZ I RULZ" appear on the radio display.

Thank you samzenpus for giving this topic the attention it most certainly does not deserve.

Comment Using RSA keys to get to IBM terminals (Score 1) 618 618

At one of the places I used to work we needed to upload daily activity files to a bank. This consisted of using RSA security to log into their system, and then running a IBM3270 terminal emulator. I found that somewhat amusing.

Comment Re: BD-5 (Score 1) 28 28

> Bede's certificated plane, the American Aviation AA-1 Yankee

The original BD-1 never matured as Bede lost interest in finishing the design and spent his time on the network of dealerships he was going to build to sell them.

The investors had to fire him and give the design to someone else to complete. They had to do pretty much a complete redesign on it.

This is a recurring theme, Bede was clearly an "ideas guy".

Comment Re:You are confusing two different aircraft (Score 3, Insightful) 28 28

> The BD-5 is a propeller-driven plane with an internal combustion engine, which Bede derived from a sailplane version he never sold


The BD-5 design was copied, deliberately and publicly, from a Schweizer glider. The goal was, always, to produce a powered light aircraft. The B model, the glider, was an offshoot of the A model. As it turned out, the A model wings were substantially under-designed, and an intermediate length was substituted on most models. All of the designs initially made considerable use of fibreglass, but the entire series was moved to aluminum as the orders poured it.

The design was flawed from conception to construction. It fails due to a well-known issue in aircraft design, as it is "close coupled". The short length of the aircraft means that there is limited distance between the various force points like the CoG and CoF and the control surfaces. Exasperating this is the rear mounted engine, which means there's only, literally, inches between the heaviest part of the aircraft and the control surfaces. That means the controls have to be made larger so they have enough force to operate at low speeds. However, this also means that they are dramatically overpowered at higher speeds. There's no way around this, its basic physics. The "solution" for more expensive designs is powered controls and artificial feel.

Worse, in terms of the length of the aircraft, moving the pilot's seat a few inches is more of a relative shift than it is in, say, a Cessna. This means the aircraft is extremely sensitive to changes in W&B. Even something as minor as burning off fuel will require constant trimming, and that trim point will, for the reasons outlined above, change with speed.

So all of this conspires to make the aircraft difficult to fly on approach. As the aircraft slows the trim keeps changing. Combine that with high approach speeds and ever-more-sensitive controls. And finally, put the thrust line above the aircraft, so if you goose the engine it pushes the nose down, precisely the opposite of what you want it to do.

There is a reason a Cessna looks like it does. It is, for the vast majority of cases, the proper layout for an aircraft. Canard and other layouts have well known advantages in particular situations, but these are generally offset by their disadvantages which is why they are used only in edge cases like fighters.

The BD-10 was a joke from start to finish. Bede had no idea what he was doing, which is not surprising because he never really did any of the design on any of "his" projects - the actual design was left to young engineers typically fresh out of university. In the case of the -10, it was designed using a piece of Mac software known as MacFlow which had a number of bugs in both the software and the models. They initially predicted supersonic performance, but this was due to a bug in the model, From that point on the performance of the aircraft continued to degrade as drag and weight increased continually.

Building a transonic aircraft from pop-rivets? Yeah, that will work...

Comment Ok, and? (Score 3, Interesting) 143 143

"Conservative cost estimates for building a single Hyperloop track from Los Angeles to San Francisco come in at US$6 billion."

Is that supposed to sound expensive?

SFO's two terminals cost well over $1 billion each in inflation adjusted dollars. The new tower was $350 million. I can't find numbers on the physical plants, like the runways, but I suspect they're similar. I think $5 billion for the entire airport is not unreasonable. LAX is significantly larger and more expensive; they're spending $270 on elevator repairs alone.

A six-lane highway costs between $10 and $26 million per mile. It's 380 miles from LA to SF, so that's $3.8 to $9 billion.

The F-35 program is one trillion and counting.

Sorry, but this number seems fine to me.

Comment There are other nations in the world (Score 1) 191 191

Every statement in this post should be postfixed with "in the US" or some variant thereof. I can't speak for Europe, but I know that here in Canada very very little of this applies. For instance...

"Legislators do not pay each other for votes."

This assumes your political system allows any sort of free voting and thus trading of votes. As far as I can tell, this is generally very rare.

In systems descended from the UK parliament, representatives are expected to vote along the party line, and there is a party whip to ensure they do. Horse trading takes place though the whip, and involves party positions and goals, not votes. There is little or no ability for benchers to arrange this amongst themselves, and they will find themselves out of the party if they try it. There are votes that do not follow these rules, the "free votes", in which case the member has to vote according to their own personally feeling or their constituent's wishes, and again the trading of votes for favors is explicitly not allowed.

Although there is still considerable gamesmanship and jockeying for positions, for cabinet positions for instance, but there is very little of the sort of rider-attachement and "hypocrisy" you see in the US system. You may not like the ruling party's decisions, but typically they at least follow party lines and pass without compromise.

"Legislators do not pay each other for votes, and every member of a parliament in a democratic society is legally equal to every member,"

Legally perhaps, but I'm unaware of any system, the US or otherwise, where this is even remotely true in practice.

Comment Re:Effect of nukes on NEOs (Score 1) 272 272

> I'm pretty confident that absorbing half of the energy output of a significantly sized fusion explosive

How do you propose to do that?

In space, the primary effect of the bomb over any sort of range, like a kilometer, is x-rays. These rapidly heat nearby objects and cause shock waves. The energy transfer is not particularly efficient.

They work great against RV's because the shock wave can cause the heat shield to detach from the underlying aerostructure. Against something like an asteroid I suspect it would damp out rather rapidly.

So that leaves offgassing from the outermost layer of the asteroid. That might be what, 0.1% efficient?

Take a liquid sodium reactor, connect it to an electrical heater that scoops up and melts the asteroid material. Allow that to radiatively cool (and even regenerate the heat) and then fire that out of a mass driver. The total delta-v-per-pound-of-fissile is going to be at least one order of magnitude better.

Comment Re:You mean NEOs like Russia? (Score 1) 272 272

> This is unprecedented in the history of the nation state mechanism ::rolleyes::

You really need to read more history. You might want to start with Pax Romana and the late 19th century, to name two.

All the nukes did was make us fight proxy wars instead. Ask Korea, Angola, Vietnam, and Afghanistan how much they enjoyed this unprecedented period of peace.

1000 pains = 1 Megahertz