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WSJ Reports Boeing To Beat SpaceX For Manned Taxi To ISS

MattskEE Re:Hmmm .... (196 comments)

Boeing doesn't do development work without a contract. So, when they got a contract to start development of their capsule, they started.

And then they stopped working on it as soon as the contract ran out. They're waiting on a new contract to resume work.

And this is a part of why aerospace/defense contractors are so expensive for the government to employ, and I say that having worked at some of them. Stringing together multiple contract awards to try to get to a larger goal, and continually going through the proposal writing process. A commercial company with a goal can strive continuously towards it in a more efficient manner, and the goal is success, not hours billed on a cost plus contract.

2 days ago
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Artificial Spleen Removes Ebola, HIV Viruses and Toxins From Blood Using Magnets

MattskEE Re:Woohoo!! (105 comments)

The nanoparticles are magnetic, not magnets, which is an important different. It means that the nanoparticles will be attracted to an external magnetic field when it is applied, but they will not be attracted to each other.

Buckyballs were banned because if you swallow permanent magnets they can attract each other and could potentially pinch two parts of your intestine together, or other such unpleasant things which would be bad for you.

Swallowing permanent magnets: Bad idea.
Swallowing magnetic nanoparticles: Good idea assuming it passes the relevant medical trials for safety and effectiness.

3 days ago
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To Really Cut Emissions, We Need Electric Buses, Not Just Electric Cars

MattskEE Re:Everything old is new again (486 comments)

It's my understanding that the electricity for the trolley buses is free.

If San Fran owns the power plant it means that they have paid for the cost of construction and ongoing operating and staffing costs, and by using the power internally rather than selling it they are paying the opportunity cost of not selling it and making money.

Free in this case just means a cost that appears in a different ledger.

about a week ago
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$10 Bet Brings Researchers Closer to Industrial Scale Graphene Production

MattskEE Re:Confusing summary - here's my version (74 comments)

Well in addition to falling apart in your hands there are some concerns that free graphene can be carcinogenic in a similar fashion to asbestos... so I'll let you try the hammock first ;)

about two weeks ago
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$10 Bet Brings Researchers Closer to Industrial Scale Graphene Production

MattskEE Re:Regular bet writ large to make interesting news (74 comments)

If it's a fiction it's a brilliant one which helps this story stand out from all of the other "Fantastic New Innovation in Graphene Which Will Lead to Large Scale Production" press releases that get put out every year.

about two weeks ago
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$10 Bet Brings Researchers Closer to Industrial Scale Graphene Production

MattskEE Confusing summary - here's my version (74 comments)

The summary was not clear so here is my version based on my understanding of the work:

Graphite is composed of many randomly oriented and sized layers of graphene. Intercalation is a process where compounds or ions can be inserted between the layers of a layered material such as graphite. These Penn State reseachers have discovered a new way to perform this intercalation by leaving out a strong oxidizing agent which was thought to be necessary but would damage the graphene.

The research advisor Thomas E. Mallouk suggested trying it without the oxidizer. The researcher Nina Kovtyukhona was reluctant to perform this experiment as she thought it would be a failure. Her advisor persuaded her to try it by making a bet that he would pay her $100 if it succeeded, and she would pay him $10 if she failed. The experiment was a success, and researchers now have a new avenue to explore for synthesizing graphene.

My personal thought is that while this is scientifically interesting and could lead to some engineering benefits down the road this will not lead to large scale production of graphene since it is just splitting apart graphene sheets from graphite, and these sheets are generally quite small. Large scale production to me would be getting fairly good uniform growth or deposition of graphene over large areas of a substrate which is of the order of 1cm or larger so that it can eventually be scaled up to the 30cm and 45cm wafers in the silicon industry. So unless other researchers come up with a way to make a graphene boule composed of decent sized graphene sheets this technique does not seem useful for commercial electronics.

One things which makes graphene research expensive is that most growth methods end up with just little flecks of graphene material in random locations on a substrate, so a researcher or technician has to manually search for these and place contacts and gates on them using a manual lithography tool. It could even be automated but this would still be orders or magnitude slower than competing technologies.

A new route to making graphene has been discovered that could make the 21st century's wonder material easier to ramp up to industrial scale.

Whenever a press release uses language like this I am forced to point out that graphene so far has had zero compelling results for electronics applications. It is soundly beat by silicon and III-V semiconductors in terms of speed and dynamic range. Graphene transistors can be made reasonably fast (for certain but not all definitions of fast) but even so the signals that they can handle are only very tiny because of the lack of a bandgap. It has some wonderful properties but also some terrible ones which make its applicability suspect.

about two weeks ago
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Tesla Plans To Power Its Gigafactory With Renewables Alone

MattskEE Re:Musk worship (260 comments)

Why are guys who run factories employing tons of US citizens in US based factories (like Toyota) who produce super reliable product with great mileage get slapped by the media when a bogus story about a gas pedal getting stuck?

Are you kidding? Just wait until Tesla slips up. They will eventually, and the media will jump all over them. The only thing that the media loves more than an underdog is the story of a fallen angel.

Media are jumping all over Tesla already.

It's happened with the Tesla car fires, which are still less common per mile driven than gasoline car fires. New York Times published a likely faked review where Tesla's data logging disagrees with the reporters account, and shows that the reporter only charged the battery to a small fraction of the capacity and ignored the low battery warnings while driving past charging stations. Top Gear also faked battery trouble on their show (it was apparently in the script before they even received the car from Tesla).

about two weeks ago
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How the Outdated TI-84 Plus Still Holds a Monopoly On Classrooms

MattskEE Re:TI calculators are not outdated, just overprice (359 comments)

When I was an undergrad, most exams in advanced science and engineering classes allowed you to bring ANYTHING as long as it didn't involve communication with people outside the room. Forget about just calculators (ANY calculator), some people would be STACKS of textbooks, and I even remember some laptops (though those were less common back then -- largescale wireless also didn't quite exist yet).

When I first had a test like this, I packed a pile of books too, along with whatever calculator I had (I think a TI-85), etc. But I quickly realized that most of this was useless. In the limited time we had, if I didn't already know the stuff, I'm not going to have time to learn it from a book.

Same here, many engineering classes I had were open book, but a few profs had closed books and some didn't even allow calculators.

I had one excellent engineering prof who allowed one page of notes to exams, but no calculator. Most of the questions were asked in a way such that there was little to no numeric computation required, and when he did request a numeric answer it was simple stuff that he expected us to be able to simply and quickly do in our head or on paper. His philosophy was that you need to understand the problem well enough and break it down to analyzable pieces sometimes with approximations so that you can get within ~5% of the correct numeric answer by hand analysis, and if higher accuracy is required it will generally be optimized on the computer with software you bought or wrote.

The homework problems would cover more rigorous computations and computer simulations, the tests were designed to see if you truly understood the problems at hand.

about two weeks ago
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How the Outdated TI-84 Plus Still Holds a Monopoly On Classrooms

MattskEE Re:TI calculators are not outdated, just overprice (359 comments)

Are there e-paper screens that are fast enough? On my Kindle there is a noticeable lag for any screen update, and periodic total screen refreshes are required. That lag would be very annoying when entering formulas, numbers, or programming.

about two weeks ago
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CPU's Heat Output to Amplify DNA Could Make Drastically Cheaper Tests

MattskEE Re:You completely missed the point of the article (27 comments)

Indeed. Using a CPU as a heater is just silly, it would be like frying an egg on the engine block of your Ferrari: technically possible but there are better and cheaper ways to get the same thing done. It wouldn't be that hard to hack together a decent computer controlled heater and sample holder/heat exchanger from a few hundred to a thousand bucks in parts (depending on how much labor you want to put into it).

Instead they have this fiddly system where they have to load samples onto the heatsink of a running computer with the motherboard out in the open, and they must be careful not to drop anything onto the motherboard which could damage it, there are ESD damage concerns, and liquid damage concerns. The temperature control cannot be that good, given the vertical temperature gradient along the heatsink base to top.

It's also disingenuous (but common) for them to merely compare the raw part cost of a DIY system to a pro system. The Pro system is much more capable and robust, support is available, and it includes the labor cost of designing and assembling it. Too many DIY projects claim a "cost" which treats labor as a free commodity.

about two weeks ago
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Low-Carb Diet Trumps Low-Fat Diet In Major New Study

MattskEE Re:What they don't tell you (588 comments)

Ever since I can remember, we have been bombarded by th e concept that there is a scale of healthy eating, and that elimination of as much fat as possible is desirable, and the ne plus ultra of healthy living is veganism, followed by vegatarianism, then low fat/high carb, then the unwashed masses of high protein, and the soulles spawn of Satan - the Atkinists.

You seem older than I and so our perspectives are a bit different. I started cooking my own food around 10 years ago. I always got the impression that vegan/vegetarian lifestyles *could* be quite healthy, but that this had more to do with the fact that these folks are more likely to put more thought and planning into their diet than the average america, eating more fruit and veg, and not eating as many empty calories in general.

about two weeks ago
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Reported iCloud Hack Leaks Hundreds of Private Celebrity Photos

MattskEE Re:Where are these photos? (336 comments)

Once the genie's out of the bottle it's over. Apparently Lawrence's lawyers are threatening to sue or refer for criminal prosecution anyone that shares the photos of her. I very much doubt they'll have a lot of luck though, even if the original source of the leak is found. If anything they're just going to make it worse via Streisand Effect.

Seriously, the Streisand Effect? This is already all over the internet and news, going after those responsible for it won't change that in the slightest.

about two weeks ago
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Scientists Craft Seamless 2D Semiconductor Junctions

MattskEE Re:Two dimensional? (49 comments)

I'm quite sure they're not idiots who really think this is a freakin' 2D plane.

Not to be pedantic, but from the same paper abstract but two sentences ahead of what you quoted:

Creating analogous heterojunctions between different 2D semiconductors would enable band engineering within the 2D plane

Which shows that they describe the full device including multiple atomic layers as a 2D plane.

Now the researchers obviously know that this is not a 2D device, in the same way that graphene researchers know that graphene is not 2D (put a gate dielectric and a gate on it and you have a very much 3D transistor). Except at least in graphene the transport is 2D, for the device is this paper there is vertical transport as well. These researchers are simply jumping on the "2D" buzzword bandwagon because it's a hot research topic.

I happen to dislike a lot of what the 2D folks are claiming in the media because they tend to make very hyped claims about their device performance. And most people understand that 2D materials are not really enablers for flexible electronics or transparent electronics because you can take humble silicon or other semiconductors down to similar thicknesses and achieve similar flexibility and transparency. Or you can make a really tiny silicon device that doesn't need to be flexible even when mounted on a flexible board. Flexible electronics is really all about packaging and interconnect (not to mention a killer app).

about three weeks ago
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How many devices are connected to your home Wi-Fi?

MattskEE Re:Why Fy? (260 comments)

I actually thought his maglight comparison was an excellent layperson analogy. In a crowded room I would be less unconcerned, although there may be several emitters, anything that is a reasonable distance away from you has been attenuated greatly by the spreading of the signal and spread out over a much larger portion of your body. I have not read the scientific literature but I would guess that the main area of interest for RF safety is the cell phone in your pocket since you could conceivably absorb a large portion of that phone's transmitting power over a fairly small volume of your body.

This does not apply to megawatt radars, or kilowatt microwave ovens, but to single watt phones/wifi there's not much to be concerned about.

about three weeks ago
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How many devices are connected to your home Wi-Fi?

MattskEE Re:Why Fy? (260 comments)

Sorry for the late response that you probably won't see. I could calculate some numbers, although getting an exact value is tricky because while with skin depth and antenna aperture you could relatively easily estimate the volume over which the RF power is dissipated into heat, I lack the background to calculate the rate at which heat will be conducted away and spread out. I'm sure that regulatory agencies have done this calculation.

You should really do some reading on the subject such as: http://www.durham.ca/departmen... (this is for Canada but from a quick google it seems informative, I'm sure there are similar US-specific references).

Anyway to give you an idea of a reasonable worst case, a typical phone or router will give off 1 watt maximum. Let's say for the sake of argument that you absorb all of that as a worst case (which you won't). Is that a lot? Not really. At about 4000 J/kg-degreesC for water it will take 160 seconds to heat one shot glass (40mL) of water by 1 degree C. During that time heat will be conducted away so you will likely see much less than a single degree temperature rise, which is safe.

If you want more detail there is ample scientific literature on the subject, but this back of the envelope calculation based on reasonable worse case conditions seems to show that the danger from RF emitters that are code compliant is negligible.

about three weeks ago
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Numerous Methane Leaks Found On Atlantic Sea Floor

MattskEE Re:Feedback loops (273 comments)

This is something where engineers know things that climate scientists apparently don't.

If the positive feedback was so strong, that the system was unstable (right half plane as it were) the earth would already be Venus. Doesn't stop climatologists talking out of the butts and proposing just such strong positive feed-backs.

TL;DR; Don't ask a climatologist a control systems question and expect a reasonable answer.

Real engineers know that reality is rarely a linear system represented only by poles and zeros. And they also know that complex systems can have multiple locally stable points, and that even stable systems may "ring" when perturbed with potentially catastrophic consequences.

Consider the humble electronic oscillator which most certainly has a right half plane zero, does its output rise over time until it blows up the universe (aka turns into Venus)? No it doesn't. And to describe the magnitude of the oscillation generally requires the nonlinear transistor model which includes things like the maximum output current of the transistor, it is not a simple linear model like the one you propose.

Earth is quite complex and while an engineer could model it as a control system it would be much more complex than the one you have proposed.

TL;DR Engineers are just as capable of being incorrect as climate scientists are.

about three weeks ago
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How many devices are connected to your home Wi-Fi?

MattskEE Re:Why Fy? (260 comments)

Now I would be extremely interested to hear why my comments would give you that impression?

None of the above reasons, only that you seem to be very concerned with low-level non-ionizing radio frequency fields which are not thought to be a health hazard.

If you want your visitors to leave phones at the door to enhance social interactions and if you don't want to use mobile devices indoors personally for the same reasons, that's perfectly okay though a bit unusual.

You get the crazy label though if you think that low level RF is a safety risk.

about a month ago
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Getting IT Talent In Government Will Take Culture Change, Says Google Engineer

MattskEE Summary misplaces emphasis on one point (166 comments)

Actually Mikey gives four reasons for the healthcare.gov problems, but the summary just focuses on the last one, probably because it sounds funny:

The original points (as summed up by me in a few words) were (1) Fragmentation of implementation, (2) Lack of monitoring of system, (3) Lack of experience by the companies building it, and (4) workplace culture clash.

about a month ago
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Harvesting Wi-Fi Backscatter To Power Internet of Things Sensors

MattskEE Re:Why use wireless power? (138 comments)

Yes and if you read their paper an RF switch is used to adjust the terminating impedance of this antenna which perturbs the reflectivity. That RF switch will consume a finite energy and power. It is an active component and not a passive component. A passive component would not accomplish the modulation.

I think it sounds reasonable that a reflector like this might be able to use less energy per bit than a conventional high-efficiency transmitter, since the RF power is being provided elsewhere, this is effectively just a modulator inserted between (or to the side of) the transmitter and receiver. However the study authors do not perform any theoretical analysis or measurement in their paper to support this notion.

about a month and a half ago

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