×

Announcing: Slashdot Deals - Explore geek apps, games, gadgets and more. (what is this?)

Thank you!

We are sorry to see you leave - Beta is different and we value the time you took to try it out. Before you decide to go, please take a look at some value-adds for Beta and learn more about it. Thank you for reading Slashdot, and for making the site better!

Comments

top

New Study Says Governments Should Ditch Reliance On Biofuels

Smidge204 Food is not the problem (216 comments)

Food production is not a valid argument, IMHO.

We already produce 2700 calories per person per day. That's plenty to feed everyone a healthy diet. The reason so many people don't have enough food has nothing to do with the amount of food available and everything to do with logistics, politics, and inequity: The food simply isn't getting to where it's needed. Growing even more food is not going to solve that problem.

Similarly, biofuel production need not make use of land that is suitable for growing common food crops. Even though I advocate biofuels, even I'm against using food crops to do so.
=Smidge=

2 days ago
top

Local Motors Looks To Disrupt the Auto Industry With 3D-Printed Car Bodies

Smidge204 Re:Nothing new (128 comments)

An modern auto plant turns out a vehicle approximately once every minute.

A car might roll off the line every 60 seconds, but each individual car takes ~20 hours to make. And that only works because they are all the same with only superficial differences.

So in short, this is about using 3D printing to prototype something before going to full production. Haven't we been doing that since the 1970s?

No, because 3D printers weren't developed until the 80s. :)
=Smidge=

about a week ago
top

Should Disney Require Its Employees To Be Vaccinated?

Smidge204 Re:its a tough subject (663 comments)

well, what is "reasonable"?? the flu generally wont kill you, as such IMO should not be mandated.

So is DEATH the only level of harm you can think of that should be avoided? Is that really the threshold below which you don't care anymore?

Going back to the food service employee analogy: It probably won't kill anyone if an employee doesn't wash their hands or use gloves...
=Smidge=

about two weeks ago
top

Should Disney Require Its Employees To Be Vaccinated?

Smidge204 Re:its a tough subject (663 comments)

Not all vaccinations last your whole life.

=Smidge=

about two weeks ago
top

Should Disney Require Its Employees To Be Vaccinated?

Smidge204 Re:its a tough subject (663 comments)

Any disease that they could reasonably be expected to come into contact with and communicate to others.

So yes, that includes flu shots. That also includes MMR, Diphtheria, shingles (if you're over 60), pertussis, and pneumo/meningococcal vaccines.

Again, it's not about risk to YOU, but risk to others. Taking steps to protect others is what "personal responsibility" is all about.
=Smidge=

about two weeks ago
top

Should Disney Require Its Employees To Be Vaccinated?

Smidge204 Re:its a tough subject (663 comments)

Sorry, nobody has the right to endanger other people through irresponsibility.

You're free to do what you wish with your body, but if your job is interacting with thousands of people every day - especially children - then you should get vaccinated so you do not become a vector of disease. It doesn't matter one bit if YOU get sick or not. This isn't about you. It's about protecting the people you come into contact with.

It's basically the same level of common sense as employees washing hands and wearing gloves when handling food. It's not about keeping the employee's hands clean.
=Smidge=

about two weeks ago
top

What Will Google Glass 2.0 Need To Actually Succeed?

Smidge204 Re:Size (324 comments)

Until you get hate mail

At which point you know about it, and can therefore be upset about it. Being aware of something is a necessary precondition to having any emotional response to it.

Otherwise it's called paranoia.
=Smidge=

about two weeks ago
top

What Will Google Glass 2.0 Need To Actually Succeed?

Smidge204 Re:Size (324 comments)

It's very, very difficult to get upset over things you don't know about.

Doesn't stop some people from trying, though...
=Smidge=

about two weeks ago
top

President Obama Will Kibbitz With YouTube Stars

Smidge204 Re:Obama (105 comments)

Wait, if he's not up for re-election... could that mean he's genuinely interested in engaging younger audiences?

The implications boggle the mind!
=Smidge=

about two weeks ago
top

Why We Have To Kiss Off Big Carbon Now

Smidge204 Re:Hypocrites, liars and communists. (441 comments)

This is why I've been pushing to argue in favor of reducing fossil fuel use not from an environmental point of view, but from an economic one. People can bury their heads in the sand when it comes to science, but people always listen when money is involved.

Even though the US imports about a third of our petroleum, that's still equivalent to hundreds of billions of dollars per year leaving our economy. If we transition to renewable energies, that money stays around a bit longer.

Renewable energies might have a larger up-front capital cost (but not by much, and it's getting better every day), but the long term costs are overwhelmingly favorable.

With the current crash in oil prices it should be clear that our economy is in the hands of foreign interests. We are hostages to international petroleum markets. Let's develop domestic sources to free ourselves from foreign influence. Remember: There's no reason why oil couldn't have been this cheap all along, and the price only went down right when we were posed to start reducing imports in favor of domestic natural gas production. We're being played!

(Oh, and if we happen to mitigate the environmental damage we're doing in the process and avoid global catastrophe, I guess that'll be a bonus...)
=Smidge=

about two weeks ago
top

In Daring Plan, Tomorrow SpaceX To Land a Rocket On Floating Platform

Smidge204 Re:Re usability (151 comments)

Well, no. The Shuttle's SRBs were a lot more than just a tube full of explosives.

They had thrust vector control; hydraulic power units, gimbal nozzles, control hardware. Electrical subsystems. Self contained navigation hardware. Range safety hardware. And of course everything was triple or quadruple redundant for reliability.
=Smidge=

about a month ago
top

In Daring Plan, Tomorrow SpaceX To Land a Rocket On Floating Platform

Smidge204 Re:Re usability (151 comments)

Except that the solid rocket boosters and fuel tanks were not reusable. Only the engines were re-used and that after expensive overhauls.

The Shuttle's SRBs were reusable, and they reused them (or at least parts of them) pretty much every launch.

The big orange liquid fuel tank was not reused, though.
=Smidge=

about a month ago
top

Science Cannot Prove the Existence of God

Smidge204 Re:This tired old saw again. (755 comments)

I think you're misconstruing what is actually meant when physicists talk about the universe possibly being a hologram.

They don't mean the contemporary "Star Trek Holodeck" type of hologram. They mean that all of the information about the 3D volume of the universe can be contained and encoded within a 2D boundary.

This is not a mathematically rigorous concept of the universe, but if they can nail it down it might have some application in explaining how gravity works and the ultimate granularity of the universe (e.g. how small the smallest possible fundamental particles can be). But in no sense would this prove, or even really be evidence supporting, the notion that our universe is a simulation within some "larger reality."
=Smidge=

about a month ago
top

Top Five Theaters Won't Show "The Interview" Sony Cancels Release

Smidge204 Re:Home of the brave? (589 comments)

I will bet your chances of being killed in a mall go way up if there are specific threats against that mall.

No, it doesn't. The mall could have been attacked at any time with no announcement at all. The only difference is now you know somebody out there has an axe to grind.

Knowing the odds does not change the odds.

In fact, I'd argue that you might actually have a slightly LOWER chance of being killed or injured if the the intent to attack is announced. They could be bluffing. Increased security could ward off or apprehend the attackers. Law enforcement might be able to intervene and prevent the attack.

The most realistic outcome of this scenario? The mall would be closed and your appointment canceled... but assuming for the sake of argument that doesn't happen, you might as well go because your odds are certainly no worse than at any other time.
=Smidge=

about a month and a half ago
top

AI Expert: AI Won't Exterminate Us -- It Will Empower Us

Smidge204 Re:AI is not just a look-up program. (417 comments)

2. See that guy in the cubicle next to yours? Prove that he is "self-aware".

The guy in the cubicle next to mine spends his lunch hour browsing Fox News, Drudge Report and Townhall. I can make a very solid case that he's not.
=Smidge=

about 2 months ago
top

Practical Magnetic Levitating Transmission Gear System Loses Its Teeth

Smidge204 Re:Efficiency??? (103 comments)

150Nm is about what a typical small car engine might be capable of at peak, but torque at the wheels would typically be greater due to gear reductions. Not really relevant, though - the torque of the engine applied to the wheels is not applied to the lug nuts on the wheels as a torque, but applied to the lugs themselves as a shear.

Maybe imperial units will help?

15 Newton-meters is roughly 11 foot-pounds. Most people can comfortably apply that kind of torque with a normal wrench, and that's about twice what a strong person could do with a screwdriver.

Torque specifications for lug nuts are typically in the 80 to 120 foot-pound range, though practically nobody outside of a reputable auto shop will bother with that (and even most reputable shops will gloss over it...). Most people, including myself, either use an impact gun or step on the lug wrench, which results in slight over-tightening. Figure a 150-lb person standing on a 12" long wrench and that's 150 ft-lbs... slightly over but not too bad.

For gasoline car engines, torque (ft-lbs) seems to always be fairly close to horsepower... so 120 ft-lbs is about right for a 120hp engine, plus or minus. It boils down to the fact that most gasoline engines are designed to run at a certain RPM, which makes the math turn out that these two metrics are often within maybe 10% of each other.
=Smidge=

about 2 months ago
top

Practical Magnetic Levitating Transmission Gear System Loses Its Teeth

Smidge204 Re:Efficiency??? (103 comments)

As the AC said, for a very limited torque; 15 Newton-Meters. For a sense of scale, the recommended torque on a lug nut for a car tire is typically around 8-10 times that.

It's also under cryogenic conditions, intended for space applications, which is a rather special case (ultra-reliable under extreme environments) where it makes makes more sense to use something exotic.

And having said that, the more I learn about it the less I'm impressed with it. Magnetic bearings are pretty old hat technologically speaking, and the harmonic drive aspect is only novel in that it uses magnetic repulsion to flex the spline cup rather than physical contact. Meh. Even their "through-wall transmission" thing is a glorified magnetic stirrer.
=Smidge=

about 2 months ago
top

Practical Magnetic Levitating Transmission Gear System Loses Its Teeth

Smidge204 Re:Efficiency??? (103 comments)

Your argument basically boils down to "since electric motors can produce high torque, then permanent magnet couplings can also provide high torque"

My contention is you make it sound way, way simpler than it is. Also, you'll find that the really big motors are not the permanent magnet type exactly because producing a high-torque motor with permanent magnets is more difficult and expensive. It's an issue of flux density.

I'm sure you COULD design a permanent magnet coupling for any particular purpose, but that doesn't mean it makes sense to do so.
=Smidge=

about 2 months ago
top

Practical Magnetic Levitating Transmission Gear System Loses Its Teeth

Smidge204 Re:Efficiency??? (103 comments)

If you couldn't move high forces with a transmission like this, then you also couldn't generate them with an electric motor, because you couldn't hope for the magnetic fields to turn the stator against high loads.

Electric motors can stall, and when they do so they draw a terrifyingly huge amount of power compared to when they're operating properly. Providing that static torque is very expensive and often dangerous unless the motor and controls were designed for it.

It's not that magnetic fields can't be strong enough, it's getting fields that are strong enough without additional energy input.
=Smidge=

about 2 months ago

Submissions

Smidge204 hasn't submitted any stories.

Journals

top

More info from Nissan LEAF Tour

Smidge204 Smidge204 writes  |  more than 4 years ago

Nissan's national tour of their new electric vehicle offering, the LEAF, recently completed its last stop at the Liberty Science Center in Jersey City, New Jersey. Nissan representatives were on hand answering questions about the car and their plans to bring it to market, and I was able to collect a lot of good information which the Slashdot community might find interesting and useful. Below is a fact-dense summary of everything I was able to tease out of them.

The LEAF is a 5 passenger, 4-door hatchback bearing a striking resemblance to the currently available Versa, although once you see it in person it becomes obvious that the car is an entirely new platform designed specifically as an electric car, rather than a tweak of an existing vehicle. First impressions, shared by other visitors I met, was the vehicle was much bigger than the phrase "electric car" brings to mind.

The LEAF's technical specifications are no less impressive, though still somewhat tentative as production is not scheduled to begin until this fall:

80kW (107.3 HP) synchronous AC motor producing 380 ft-lbs (280Nm) torque. 24kWh worth of air-cooled, modular (48 modules, 192 cells total), laminated lithium-magnesium batteries located under the floor and rear seats giving a listed driving range of 100 miles (as tested under LA4 methods, aka "the city test") and a max speed of over 90MPH (144KPH). Curb weight is approximately 3300 pounds (1500 kg) including the 480 pound (217 kg) main battery pack. The main battery is rated for full capacity from -30ÂF to +100ÂF (-34ÂC to +38ÂC) and has a life expectancy of 7 to 10 years, with "end of life" defined as capacity degraded to 70% of the original. The LEAF comes with four wheel disc brakes and two stage regenerative braking which can recover up to 30% of the vehicle's kinetic energy in most situations. Brakes are hydraulic (w/ electric booster) and steering is drive-by-wire. A cable operated parking brake is also included.

Power from the main battery is cut in the event of an accident for safety. It is not known if a separate kill switch for disconnecting the battery manually will be provided.

The LEAF is capable of three charging options: it comes standard with a 110v outlet charging cord, allowing you to plug your car into any 15 amp outlet for charging via the charger incorporated into the vehicle itself. Charge time for 0% to 100% is estimated at 16 hours using 110v. Alternatively, you can charge the car using 208v using a required "charging station" in about 8 hours from 0% to 100%. Both of these methods use the same J1772 socket, recently made a standard by SAE International, meaning this and all other vehicles that plug in to charge will use the same connectors.

The 208v "charging station" is, I was told, simply a surge protector and over-current protection device which must be professionally installed and certified for code compliance and liability issues. While Nissan plans to offer Nissan-brand charging stations, you will not be obligated to buy one as the 110v charging cord is supplied with the car. Charging stations may also become available from third party manufacturers since they do not contain anything proprietary, and like the J1772 connector should be compatible with any plug-in car on the market.

The third "quick charge" option uses 480v connection through a second, dedicated socket and connector and can charge a dead battery to 80% in just under 30 minutes. Quick charging is halted at 80% to prevent damage to the battery. There are no plans to offer quick charging stations to the general public since very few houses have 480v electric service available. Nissan is working with private companies to install both 208v and 480v public charging stations for general use.

The LEAF includes, as standard equipment, an integrated GPS navigation system which helps you plan routes that pass near by public charging stations. Monthly updates to the navigation system will be provided for free. Also included is 3G communications which allow the on-board computer to send and receive data via the internet. The computer can be configured to send e-mail status updates, and various features such as charging schedules and heat/air conditioning operation can be done remotely via internet connected PC or cell phone. When asked about privacy concerns, the reps said that Nissan plans to collect usage data via an opt-in program only from their initial test users. There are no long-term plans to monitor driving and charging habits.

Other standard features include heated seats and steering wheel, air conditioning, power locks and windows, AM-FM/CD stereo with aux input for portable players, keyless entry/startup and 24/7 roadside assistance. All vehicle lights are LED. Features that are not offered include power seats, sun roof and spare tire.

The "ignition" is a large power button located just below and to the right of the steering column. The rep said there is no delay turning off - meaning you don't have to hold the button - but she never tried it "at speed" so it is unclear exactly what will happen if you turn the vehicle off while driving.

There is no set price yet, but I was given a target range of $28,000 to $33,000 before rebates and incentives. Official pricing is due to be announced in April. At present, the LEAF qualifies for $7,500 in federal tax rebates, along with 50% of the install cost for the 208v charging station (up to $4,000). Additional rebates and incentives may be available from your state government as well. Nissan plans to offer buy and lease options, but they can not offer battery-only leases due to federal laws. The federal government considers the battery to be part of the drive train, and it is illegal to sell a car without a functioning drive train.

Production is scheduled to start in Japan this fall, with a portion of those vehicles being imported to the US for test markets and early adopters. Official announcements are scheduled for December of this year. By 2012 Nissan plans to have a vehicle and battery manufacturing plant operating in Tennessee with a capacity of 150,000 vehicles and 200,000 battery packs per year.

Slashdot Login

Need an Account?

Forgot your password?