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Comment drawbacks, fuel maps (Score 1) 375

Thank you for mentioning the details of what the damage means and for mentioning energy density. That's a real-world drawback we experience immediately. Ethanol does create domestic supply chains for oil for many nations though, and it's always beneficial to have a variety of effective methods to meet major demands of our societies. While the octane rating is higher for ethanol than gas, since we still buy the same ratings I can only assume oil companies are reducing the refining costs of the gasoline to minimize the net cost of the fuel.

For a data point on the car's behavior and how well optimized it would be to use a blend, I retuned the ECU on my 2006 Honda S2000 with a product by Hondata. The fuel injectors used a preset fuel-air ratio settings map for wide open throttle across the RPM range, and it used an oxygen sensor to approach ~14.7:1 air:fuel for part or light throttle. It was an open loop system with a long and short term fuel trim adjustment to keep it close to that target. The wide open throttle settings map was a little more rich than stoichiometric to keep the motor safe since running lean produces detonation--it targeted around 13:1, but the precise number seemed to vary by car model and even by individual years of the same make and model; a major trend was turbocharged cars typically were more rich than naturally aspirated vehicles. I understand my 370Z and others work generally the same way.

Comment Boeing's rationale (Score 2) 242

Boeing has an explanation of the rationale and the steps they've taken to examine the effects of electronics on aircraft in their "Aero" magazine. This is pretty old (2000) and would certainly benefit from an update, but they did real live technical investigation instead of just mixing assertions with quasi-technical arguments. A link to the full text:

TLDR Summary:
After receiving very specific, detailed claims/complaints from airlines, Boeing inspected the frequency range output and dB level of electromagnetic emissions from several specific devices. Their biggest concerns in the testing seemed to be the EMI due to frequency harmonics and interactions between devices--the premise and conceptual explanation seems unlikely but isn't completely meritless. No airplane susceptibility was demonstrated. Boeing clearly said that since they tested specific items, the testing was not conclusive for all devices and all interactions.

The excerpt on cell phones in particular deserves to be fully quoted, as it illustrates their thinking:
*Cell phone tests and analysis.*
Boeing conducted a laboratory and airplane test with 16 cell phones typical of those carried by passengers, to determine the emission characteristics of these intentionally transmitting PEDs. The laboratory results indicated that the phones not only produce emissions at the operating frequency, but also produce other emissions that fall within airplane communication/navigation frequency bands (automatic direction finder, high frequency, very high frequency [VHF] omni range/locator, and VHF communications and instrument landing system [ILS]). Emissions at the operating frequency were as high as 60 dB over the airplane equipment emission limits, but the other emissions were generally within airplane equipment emission limits. One concern about these other emissions from cell phones is that they may interfere with the operation of an airplane communication or navigation system if the levels are high enough.

Boeing also performed an airplane test on the ground with the same 16 phones. The airplane was placed in a flight mode and the flight deck instruments, control surfaces, and communication/navigation systems were monitored. No susceptibility was observed.

Telephones installed and certified on the airplane by Boeing or operators are not actually cell phones, but part of an airborne certified satellite system. These phones are electromagnetically compatible with the airplane systems because their emissions are controlled. In contrast, the emissions from passengers’ cell phones are not known or controlled in the same way as permanently installed equipment.

Comment The math isn't the moral question (Score 1) 604

The calculus of societal interests isn't the question. At the core, we have a larger moral question:
Is it ethically right to plan to kill one innocent person if it should save the lives of five, ten, or whatever number of people?

Individualist thinking is inclined to argue it's unconditionally wrong to knowingly place (force) an innocent person onto the altar to die. Societal/communal thinking is inclined to argue the greater wrong is that which produces the greater loss, therefore the innocent one must (perhaps unwillingly) give his/her life to preserve the safety of the others. We cannot expect our society as a whole to make a unified decision here; we must instead be convinced that we don't need to ask questions that are this hard.

Rather than trying to decide how many deaths are too many, we need to convince ourselves we've solved this causes-of-death question before we implement the solution. This will probably mean we first solve it for specific, well-controlled roads/freeways, and then over time we can extend the solution outward to additional classes of roads and conditions.

Comment Wind Tunnel - CFD / Aero visualization app for iOS (Score 2) 165

The iOS app Wind Tunnel is a pretty good simplified fluid dynamics solver. It has air entering one side of the screen, exiting the other, and the sides of the screen are free edges. You then draw airfoils or shapes with your fingers and see how the fluid patterns change. You can tweak quite a few parameters. For instance you can change speed, look at pressure and vorticity plots as well as velocity, and introduce particles to see where they go. He spent a lot of time on getting the visualizations to look impressive.

It's incompressible flow and he said he was forced to sacrificed some exactness (allowing a bit of mass loss vs. the N-S equations in some circumstances) to get the computations to run efficiently on iOS hardware in realtime, so the visualizations are pretty reasonable but the numbers won't be exact. Overall it's a great app with a solid math/science/engineering foundation.

Comment Supersonic parallel (Score 1) 235

There's no reason this needs to blow up the arrival (or departure) port; it's loosely analogous to supersonic travel producing sonic booms from stacking pressure waves. Supersonic aircraft don't blow up the airports or home cities.

Besides, we need to figure out negative mass before this is a big deal.

Comment 13.75 billion light years (Score 1) 228

I think this is pretty neat. I hope we as a race can soon learn more about why and how to effectively communicate/teach that to simple white collar desk workers like myself.

This proves nothing about the long term generation of all stars everywhere though - this is a trend describing the stars in our universe, so it's an observation based on the restricted population of those stars within 13.75 billion light years of us in observed spacetime.

I'm kind of curious what's outside that box. Let's fund that starship. Maybe my great grandkids will find out.

Comment Performance of product - seems promising (Score 4, Interesting) 208

This will require some years of development, but it certainly shows promise.

The strength and stiffness of a fiber are not the performance we'll directly obtain from the materials. It's more like a potential number. Typical 'carbon fiber' products have on the order of 60%-75% fiber and 40%-30% plastic by volume, where epoxy is one of the most common plastics. The carbon fibers contribute strength and stiffness, but it would fracture easily with a rigid binder. The softer plastic binder acts to share and redistribute loading efficiently (after some fibers break) to keep the carbon fibers more or less all carrying load effectively.

They'll have to go experiment until they find which plastics work well with this. That took a long time for composites since if the plastic binds too strongly to the fibers, the resulting composite is very brittle and loses a lot of potential strength. Also, to optimize the bond strength, carbon/kevlar/glass/etc fibers are typically treated with a 'sizing' that help the fibers bind optimally to a targeted plastic or set of plastics. Hopefully this new material can leapfrog off of the progress and work of the composites industry. Humidity will also be a concern that requires some testing and may cause some compromise on binder selection.

Also, 'typical' fiber properties really depend on the application. A typical aerospace carbon fiber is Hexcel IM7, which shows considerable improvement over the properties they reported in the article, and others can be a fair bit better or worse. The IM7 6k tow fiber is reported to have:
Ultimate Tensile Strength: 5.15 GPa
Elastic Modulus: 276 GPa

Sample properties of one finished product provide:
Ultimate Tensile Strength: 2.5 GPa
Elastic Modulus: 163 GPa

A few years ago the least expensive carbon fiber would sell for ~$15/lb raw material with the epoxy typically around $9/lb, and the IM7 fiber above is probably an order of magnitude more costly. I don't know what figures they used for their cost comparison, but they can't really have the whole cradle to grave process figured out at this stage anyway, so we'll see what happens when they get some material fabricated.

There's a lot of work ahead, but this seems promising!

Comment Cognitive dissonance (Score 1) 1774

Subscribing to young earth creationism doesn't necessarily mean the individual is unable to think critically in general. An alarming amount of cognitive dissonance would easily enable that belief to be written off by the believer as a simple exception in a world view that is otherwise near-identical to the world view shared by the rest of the first world.

Not all people bother to develop a coherent world view. It's not always important to them.

Comment Re:Lets be honest here. (Score 1) 544

If we could have fought the war the same way as WWII - pure brute force, civilian casualties are acceptable, and the goal was to cripple the clearly organized semi-public military-industrial complex of the enemy nation - the US military would have caused the Afghan rivers to run red with blood and then left in less than a month. But you can't overcome an underground third world loose alliance the same way you can conquer a first world government.

Honestly, I pity the people in Afghanistan, especially after the cold proxy war and the civil war following the Russian withdrawal in the late 1980's. Thankfully, the Afghan nation is slowly recovering due to international aid. Strange as it sounds, I admire the humanitarian benefits this war has brought to Afghanistan. I don't mean it's worth the price - perhaps, perhaps not - I'm just reflectively trying to see the glass as partly full.

Comment Re:Not mutually exclusive (Score 1) 1218

I'm a mormon church member, and I feel the same way. Science is there to answer questions about how things happen and to help us develop a framework for understanding the world around us. Religion answers fundamentally different questions about how to live, and it has historically relied heavily upon teaching philosophical principles through metaphor. The targeted historical cultures were frequently uneducated savages - not so enlightened as to be able to reason using abstract logic. The first books we have, including the creation account, were targeted towards teaching slave tribes the principles of basic humanity. One of the first steps was to simply stop worshiping their melted earrings (golden calf) and look forward to something better.

Sadly, rather than attempting to learn from these ancient accounts by considering the full context and understanding what lessons were being taught, some christians preach a lazy literal interpretation of the existing translations of the original accounts. Worse yet, rather than resolving (or at least quietly accepting) the conflicts, they then begin to anger and yell about how since that infantile view contrasts with the scientific method, science must be ignorant and wrong.

As a christian, I understand why many people despise this type of religious zeal. The blind faith and follow-the-leader mentality can be frighteningly similar to the cargo cults and the Jim Jones massacre. Please remember, at least a few of us christians know better!

Comment Re:Scandanavia (Score 1) 999

The Scandinavian cultures are able to pull it off because of their citizens and culture. The US and many other nations are not able to duplicate the model because of their citizens. The economic and social models can work extremely well, but they fall apart if enough of its citizens choose to abuse and exploit it for personal gain at societal expense.

One Finnish woman I knew told me she wanted to take a vacation to Spain for two months but didn't feel like waiting for the vacation, so she said she planned to quit her job and started collecting the very generous year-long Finnish unemployment package (~75% of her wage). She'd hang out at home for the duration of the year while she collected checks, then she would probably go back to working again. I didn't hear from her after her trip, but she did at least head out for Spain according to that plan. The economic model can be sustained because most of the population doesn't do what she did.

Comment Along the same lines (Score 1) 999

Rather than discussing social and other items statically, I would focus more on how well the culture's priorities match or fit those of the OP.

*The US prioritizes economic productivity, efficiency, and convenience at the expense of other virtues.
*People in the US benefit from decent wages, low total taxes and cost of living --> very large new homes and nicer cars, good entertainment/music, and 24 hour stores are everywhere.
*The US suffers low quality or high costs for education and is straddled with a need to maintain health insurance or bear that as a financial risk.
*Usually public transport is weak because of the urban sprawl, but cars are so cheap and convenient that hardly anyone cares.

Compare that package to others that might meet your wants and needs.

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