You are thinking about a slow boat in displacement mode, or a wave-surf board with very small fins. But I can tell you that the wetted surface area of my wing-foil board is exactly zero after takeoff, and all wet surfaces of the foil are, for a significant percentage, in laminar flow. Same for a windsurf board planing: just the last 50cm of the board is touching the water and the fin is extremely significant for drag.
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Maarten88
Surfboards will have a Reynolds number of 10^7 which is entirely turbulent.
A fin, foil or daggerboard below the board/boat is operating well within the range of Reynolds' numbers where laminar flow is relevant.
Any competitive sailor or foil-racer knows that the underwater surface has the least friction and best laminar flow when sanded with fine-grid sandpaper, around 1000 to 1500 grid.
It always surprised me that this was not true in air and airplane wings were supposedly best when glossy. So now it turns out that this is indeed not true, and airfoils also benefit from micro-roughness for lowest friction.
Now the surprising question to me is how is it possible that something so simple was not known in this very well-researched and well-funded field. It probably was known, just not by the paper-publishing researchers.
I don't know which side is more likely right in this scenario.
What are the motives? Follow the money? Who profits most might give an indication of who is more likely wrong.
You know the carbon footprint concept was literally created by BP marketing, to place the blame for climate change on society, and distract from all the evil stuff they did to promote more fossil fuel consumption and sabotage climate science.
The Climate Town channel on Youtube has lots of video's on this, such as this one: https://www.youtube.com/watch?v=1J9LOqiXdpE
people who believe that crashing the US, including the dollar, enables them to build a US like they want
Yes, it's strange how dumb some rich/succesful people are. As I understand it, no civilization ever has done such a thing. If a civilization and its institutions crash, it remains failed/dysfunctional for a very long time. The only way to improve society is in small steps.
I hope the people who finance this all will wake up to the reality that it may well cost them everything, too.
Titanium's advantage is imo not so much its weight, as aluminium is better still in that respect. Titanium is mostly better where corrosion and temperature resistance are important. Relative to weight, high grade steel, titanium and aluminium are about equal in tensile strength.
why nobody was doing this in 01890, 135 years ago
Maybe because at that time tropical hardwood was readily available at low cost?
I'm pretty sure healthcare costs in the US are also higher as a percentage of GDP compared to EU, so higher wages would not explain the difference. Also productivity should be higher?
I think pharmaceutical, hospital, insurance and legal companies take all the money.
much more expensive and for no good reason
There is a good reason: profits and management pay. And greed is good, right?
the problems are fixable
Fixable in theory. The US would first have to fix the underlying issue, which i.m.o. is government, media and even judicial capture by financial interests. Billionaires are now openly buying "shares" in those. I don't see any sign of it changing anytime soon. It only seems to get worse.
The investigating is great, the problem is who is doing it and for what reason.
If the misdeed is done by a non-public or poor company there is no money to be made so they would never even investigate it. And not accepting a payoff that returns more than the short position would be ignoring fiduciary responsibility, so some investigations could disappear.
It's very worrying that consumer protection against poisoning in the US comes from a for-profit company that makes money by short selling companies they found to have issues and then covering their back this way against lawsuits, which any less aggressive reviewer would face.
With all the anger over illegal immigrants taking US jobs, as a European it surprises me that nobody in the US seems to even mention the idea of punishing the employer for employing illegal workers.
If I want to hire someone (local or remote) as an employer here, I better make sure the worker has a valid working permit. Fines for non-compliance towards the employer are huge, even for a single day of work. All paperwork has to be complete before any work is done. Even when hiring through intermediary companies who guarantee it's all legal, liability and fines remain in place for the ultimate employer if it turns out to be not so.
Disruption at work. Ford can't make money on selling EV's, their overall margin suffers with every EV they sell. They have large existing investments in factories, processes and people that produce combustion engines. They can't lower prices and sell enough of them for economies of scale to start working.
Tesla is the new Ford. Ford (and most other car manufacturers) will have a difficult time, most manufacturers are probably doomed. After the current hesitation phase, when the economics are there (very soon), customers will almost all go electric.
the bus is a strictly worse version of the car in these kinds of cities
You can change that by giving them their own lane so they don't get stuck in traffic with the cars, let them go where cars may not go, give priority at traffic lights etc. That is what they do where I live.
It's hard to educate the next generation when everyone of all ages is exposed to relentless propaganda (also known as marketing, in all forms including the fully legalized corruption of US politics) at the same time.
Oil and car companies' futures depend on continued public support for free parking, more lanes and housing far away from destinations. It's in their interest to manipulate people into opinions that are beneficial to their bottom line, and they will continue to do so.
I’ve read articles where even on a per capita basis just about everything is more costly in dense cities, from sewers to schools.
Link? This NotJustBikes video suggests it is the other way around: https://www.youtube.com/watch?v=7Nw6qyyrTeI
Tax haul for 10 houses are better than a 10 unit complex.
I thought is is pretty well established that in US cities, poorer and denser neighborhoods are subsidizing the richer suburbs, tax-wise.
Because 10 houses need 10 of everything, paid for by taxes: street pavement, sewer, water, electricity, internet, etc. A 10 unit complex needs only one. It all needs maintenance too, starting some 25 years after being built. Most US suburbs can't pay for their own maintenance from taxes.
I'm generally okay with Ads, that is fair. But I'm not okay with tracking, consolidating data about me from different sources, analyzing it and selling that. It is too hard to understand how that may impact me and others.
Does this rule exist in any other sports?
In sailing, boats are required to render help to a boat that is in problems, before continuing their race. Boats that render help are compensated for the loss in position/time in the race afterwards, by a jury.
Those RC dynamic soaring gliders pull up to 80G, which might also be an indication that this is probably not a good fit with manned flight.
Since when is it a crime to harm childrens health for money? Coca Cola has been doing it for 50 years, nobody seems to have a problem with that.
It's annoying how the article shows that independent activity/movement of children has declined drastically in the US and UK over the past 30 years while suicides have risen and how this contrasts to Finland where young children are much more independent. But then it somehow fails to compare the trends in teen suicides between those geographies and does not prove the point.
A close relative was recently diagnosed with cancer and is undergoing chemotherapy. I tried to read up on cancer research and therapies and stumbled on several youtubers interviewing Thomas Seyfried [1], a researcher who thinks cancer is caused by damage to cell mitochondria that provides energy, and not by damage to cell DNA. His theory is that cancer cells get energy by fermentation instead of oxidation (burning). Taking away suitable energy sources for this process (glucose and glutamine) would make cancer cells very vulnerable and enable treatment with much lower doses of chemicals. His advise is to attack cancer foremost by fasting and then chemicals. I think he also mentions / uses the DON chemical this article touts as a way to inhibit glutamine getting to the cancer cells.
This theory seems very persuasive to me. The more research articles I read, the more they seem to confirm this theory. This article is yet another one.
My relative undergoing therapy was given the advise by the doctor to eat as much as possible during chemo treatment, to stay strong and feed the immune system. Which is completely counter to this research. I am not a doctor, but I worry!
... new cities to be designed differently in several ways. One of which is for roads to be only for small autonomous vehicles and entirely separate ...
As I understand it, this vision does not compute. The number of movements of people in a dense city is too large for everyone to move in a car, autonomous or not. Cars take a lot of space. They need to stop someplace for someone to get in and out, merge in and out of traffic. Streets cant be designed in a way that accomodates this at the scale of a city like NY.
Similarly, in spread-out suburbia, autonomous cars would still get stuck in traffic jams if everyone has to use them to get to work. Making cars autonomous makes things a bit more efficient, but not by orders of magnitude.
Mass transit, combined with walking and biking, is simply way more efficient for moving people in cities and is a proven model that does scale.
On cultural issues I agree this site leans progressive, from a US perspective. (from my international perspective, politics in the US seems to be between far right and religious fundamentalism).
But arguing for more regulation, consumer protections and limiting the influence of corporations or wealthy individuals has never gone well on HN. Which is understandable, given its origins and owner. It's really slanted towards business/entrepreneurship.
No, the majority voted for Hillary, but Trump won.
I recently was in Netherlands trying to get from the Hague to the islands south of Rotterdam and it was also quite confusing.
You can just swipe your phone (Apple Pay / Google Wallet) or credit/debit card to check in and out (do not forget to check out!) and you're done. Works for all public transport in the Netherlands.
Of course there are also more traditional ways to pay for your ticket, but it does not get much simpler than this imo.
What should the consequence be for bankers who take too much risk, their banks' failure spreading to the wider banking system, sending the economy into a recession and millions of people into poverty?
Consequences (claw back) is the least that should happen, but it doesn't help the victims and might still incentivize short term risk taking (I win vs you loose). The solutions that the article offers (only allow long term incentives, include the interest of the entire banking system) might actually stimulate better risk-taking behavior. The real economy is slow, bankers' incentives should be too.
They may operate in an alternate reality, but they are probably very sensitive to success and wealth. In their world successful people can't be wrong. Making him poor may be more effective than pointing out he's a nut.