Become a fan of Slashdot on Facebook


Forgot your password?
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×

Comment Re:Does it scale? (Score 1) 130

Your math is right based on the summary but the article says:

"With a stable system and a turnover frequency of 360,000 moles of hydrogen per hour per mole of catalyst, the potential here is real."

Yes, but the specific numbers given would indicate 360,000 MOLECULES/hour, which makes it seem much more likely that the article itself misspoke by saying "moles" where it should have said "molecules"

Sanity check: 360,000 moles/hr per mole of catalyst = 100 moles/sec per mole of catalyst = 6x10^25 reactions/sec per molecule of catalyst.
You can't get a reaction time of 1/(6x10^25) sec = 1.7x10^-26 sec for chemical reactions in our current universe (maybe in a Big Bang)
  1.7x10^-26 sec is FAR less time than it takes a photon to cross the width of a proton (and a proton happens to be an H+ ion)

Comment Let's put this saving into perspective (Score 1) 297

First, let me say that I am all in favor of this change. Relatively modest engineering changes and updates to reflect currently available electronics components may only cost pennies and can actually save manufacturers money, but all too often the manufacturers shortsightedly avoid such NREs [Non-Recurring Engineering] costs in favor of more "marketable" changes. In their defense, it is not always obvious when to do such a review: annually seems excessive/wasteful but once a decade seems too long -- and if you set a goal of once per decade, it's easy to slip to once/11 years, 15 yrs or why bother? Legislation can be a useful spur to changes that benefit both the industry and the consumer.

But having said that...

Saving $300M amounts to less than $1 per man/woman/child in the US -- and that's over 30 years! So about $0.03/yr/person Less, when you consider that US population is projected to be over 400M by 2045.

Similarly, the current US housing stock is estimated to be 135M housing units per the 2013 National Housing profile, so 6.5M homes is about 5% of current stock (ignoring 30 years of future growth" and 1 year's consumption for 6.5M homes, spread over 30 years, is about 0.167% of home usage.

Comment Re:Mostly sure (Score 5, Insightful) 117

As a physician, I can tell you that every US medical student I've seen had to do/learn all the basic proctology tasks/diagnoses, and residents must learn the entire general range of proctology tasks/diagnoses. While most schools don't let a student do, say, full hands-on supervised colonoscopies for liability/inexperience/billing reasons, their residency will expect them to. A proctologist (as you term a board certified internist, with further training leading to a board subspecialty as a gastroenterologist) is an expert, there are no "proctology interns".

I say this as someone who feels US medical care suffers from our excessive (sub)specialization, at the expense of trained generalists.

As abusive as I feel the med school/residency system is, this is one part I agree with: any physician SHOULD have a thorough grounding.

Comment Re:"Incorrect" MPG numbers (Score 3, Informative) 177

The make/model/package MPG figures come straight from the manufacturers, who usually don't even test production models, but pre-production engineering prototypes --engineering prototypes!-- and report that figure for as many production years as they like

According to the EPA itself: "How vehicles are tested"

Each year EPA tests a random sample of maybe 10% of the base models on the market. Note: this is a much smaller number than the various "apparent models" (variants, options packages, etc.) that a consumer might feelare different cars. Aside from perhaps testing a second engine option in a given model, the EPA ignores those variants and doesn't even require tests to be conducted in successive production years because it feels "MPG probably won't change much from year to year" and "almost no options would affect indoor dynamometer results anyway -- we know it's a poor test". Aerodynamics is just one the options that significantly impact real world MPG, but won't show up on a dynamometer

Therefore MPG numbers are just a manufacturer's own claims, subject to spot-checking by the EPA. Apparently VW, Kia, and others felt the risk of spot check was small enough to ignore.

Comment Re:Why? (Score 4, Informative) 106

SpaceX's Dragon has already launched to orbit 8 times, including 6 full resupply missions to ISS, autonomously. It rides the Falcon-9, which has successfully reached orbit 18 times.

The manned Dragon capsule configuration (aka Dragon 2) is expected to do a demo flight in about a year. It was delayed by the accident investigation due to one faulty support spar (of which thousands had already flown) in May of this year. Falcon 9 is scheduled to return to flight in about a month, but it has a backlog of missions/payload before it can fly the Dragon 2 Demo flight, currently expected in the second half of 2016.

Yeah, we temporarily stumbled on manned space flight -- but we've done so before (e.g. after the two Shuttle disasters). It's not permanent.

Slashdot Top Deals

Enzymes are things invented by biologists that explain things which otherwise require harder thinking. -- Jerome Lettvin