HN user
contact me if you work in wind
I do not think that. This similarly applies to both sides of some other contentious scientific/medical topics which can easily get someone labeled an “antivaxxer” as an ad-hominem directed without solid reasoning. One imagines what labels were given to those who did not support widespread leech therapy at its peak…
Very clear visual. Does anyone have a similar visual reference for how quadraphonic records work?
Sounds like you’re in the market for the EV mini.
Which is what makes these misleadingly-marketed features so controversial…
Can you provide a source re:19th century dog breeding with wolf genes? Very curious!
FORTRAN, glorious FORTRAN.
Under what criteria?
What about fuel injected 4-strokes? (Maybe these don’t exist in the leaf blower market yet).
Seems like the most impactful solution would be an EPA or CARB ban on sales of new two-stroke lawn devices. Although this article suggests a switch to battery powered devices, four-stroke replacements more easily fit the niche than something which degrades in charge and takes a while to recharge at that.
What about the tail risk of mismanagement of spent fuel?
Chernobyl may not even necessarily represent the tail risk of a nuclear catastrophe. After all, only one of the four reactors melted down.
What is your evidence that the tech "becomes safer with time"?
Redundancy is your friend. If you are serious about data retention, you should be storing your most important data offsite. If you are serious about privacy, this may require backing up to a hard drive and physically storing that offsite yourself.
Great article. Lightning concerns are affecting wind turbines design choices in many ways nowadays. I know several OEMs use fiber-optic cables to connect to load sensors within blades to prevent lightning damage.
I agree, as someone who likes a lot about Python (particularly its wide selection of libraries), the whitespace sensitivity is annoying.
However, it seems like part of the language that could conceivably be removed in future versions if defending it wasn't such a priority for many.
What a beautifully written piece. The statistics about childhood COVID risk need to continue to be broadcast far and wide in context of the other risks of life.
Great piece, thanks for posting. The misleading media narratives on Florida don’t only affect Florida, but are also meant to strike fear into the heart of Americans and kill hopes for normalcy. A future without constant fearmongering over COVID would take away the power gained by the mass media during this pandemic. It goes against media interest for pandemic fear to end.
So what is it about? This interview contains a lot of questionable claims.
I personally agree with you.
Or simpler: remove all zoning restrictions.
IMO this is a good thing, and should be applied to all manufacturers of driver-assist technology. Tesla has certainly been at the bleeding-edge of overly optimistic and confusing marketing for their product, but others should be on alert too.
Yes, floating wind is a growing research area that may be successfully commercialized within the next 10 years. There are a variety of different substructure concepts, some of which have been tried at full-scale, though not quite this large. A recent example is the Tetraspar project [1]. The primary motivation for floating wind is the ability to access areas of the ocean with high levels of wind resources that have water depths which make it uneconomical to construct and install a monopile foundation.
[1] https://www.stiesdal.com/offshore-technologies/the-tetraspar...
What kind of phone was it?
The solution that seems most fair to Tesla, all other manufacturers, and road users seems to me to be mandated driver monitoring for all driver assist systems.
Regardless of your feelings on the abilities of Autopilot, driver monitoring could go a long way to prevent the predictable abuse of the system which seems to be prevalent with a certain cohort of Tesla posters on social media.
The problems associated with the marketing of “Autopilot” and “Full Self-Driving” are a different problem entirely.
Yes, and as I understand it, the COVID vaccines under EUA are exempt from even this vaccine court system to date because of an HHS declaration in March 2020. So this isn't changing?
https://www.govinfo.gov/content/pkg/FR-2020-03-17/pdf/2020-0...
Does this have any effect on the exemption from liability for this drug or is that still in effect until 2024? I haven't seen any language on this.
Interesting paper. When I refer to "wake blockage", think of the turbines in the middle of a huge grid of machines. The energy in incoming wind on any side of the farm is mostly extracted by the outer turbines. The inner turbines typically produce ~15-20% less energy due to this effect. Also, the wind hitting them is more turbulent/"dirty" as it recovers back to free-stream velocity behind the front row of machines, which can cause abnormal fatigue patterns.
That's definitely of interest to me, although I think that manufacturers are interested in it. Many manufacturers are very conservative with installed/environmental conditions of their production machines and want to minimize risks, instead of potentially alienating a developer by suggesting a scheme that could fatigue turbines or have other unintended consequences. If anything, the paper suggests to me that if adopted, manufacturers could sell even more turbines!
Fair. I once was told by a senior NREL engineer that industrialization of a different concept than HAWTs would take over $1B in investment. Which is a lot in a low-margin, capital -intensive business like wind energy. And that number is probably on the low end.
Kites have the potential of much lower material costs to produce energy. If you have a pumping cycle kite, the "support structure" is the tether, compared to the tower and foundation required for a HAWT. The problems are indeed well known: 1. Tether material difficulties. 2. Need for self-launching 3. Airspace sharing problems at heights of kites 4. Controller design. This last one is what intrigues me personally.
The paper looks at vertical turbine arrangements, but the linked article about the paper starts with "The research suggests that the now-familiar sight of traditional propeller wind turbines may be eventually replaced by the sight of wind farms containing more compact and efficient vertical turbines." I had to respond to this rather wishful statement.
I think the bladeless vortex concept makes no sense. Here's why:
1. The surface area of the machine is small. Think of this as the area that can capture power from the wind. Due to the cylindrical shape this is way smaller than the rotor area of a HAWT or even a VAWT.
2. Vortex induced vibration [1] is a real phenomenon that can extract energy from a flow. However, to extract this energy, the natural frequency of the structure must synchronize with the vortex shedding frequency of the flow around the structure. This is called "lock-in". Since the wind is a highly variable resource, it will not consistently be in this "lock-in" range in real-world conditions. To give perspective on the norm for HAWTs, pitch control for the blades is used along with generator torque control to achieve power production from 3 m/s all the way to the maximum (cut-out) wind speed of ~25 m/s.
Wind turbine design engineer here:
There are several significant barriers to adoption that VAWTs face.
1. The wind resource is more powerful and more consistent higher off the ground. The hub heights of industry standard horizontal-axis wind turbines are reaching 135+ meters for the new generation of large offshore machines. These vertical axis machines are much lower to the ground.
2. Contrary to the claims of the authors in the Renewable Energy Paper (they say "The potential applications for VAWTs are endless, because the turbines are cheaper and easier to manufacture and maintain. "), vertical axis turbines have consistently had fatigue issues. There is an interesting history of the test-campaigns of vertical-axis machines at Sandia National Laboratories [1] that discusses this. In the 70s and 80s vertical machines were much more common than they are today.
3. It is a huge risk for an industry that is shipping proven technology to switch to a new paradigm that will require much more research and testing to work at scale. It's certainly possible and I find the possibility fascinating as a curious engineer. I would love to have a secure position developing VAWT tech or working on airborne wind machines (check out ground-based generator concepts to get an idea of where I think that will progress, not ill-conceived onboard generator kites like Makani).
The problem of wake blockage in large wind farms (and from adjacent farms to each other) is definitely significant though. The current "top" strategy is wake steering, where turbines at the front use their yaw drive to capture less power and allow for more power to reach the turbines in the rows following. [1]. The bleeding edge of this may be vertical wake steering, which can entrain high-energy wind from above the farm into the plant to capture more power [3].
[1] https://energy.sandia.gov/wp-content/gallery/uploads/SAND201... [2] https://www.nrel.gov/docs/fy17osti/68396.pdf [3] https://ieeexplore.ieee.org/document/7963037