gene-h

25 ms·

91.
by gene-h 4y ago
The transmitter would be located in geostationary orbit ~35,000 km away from the receiver, so spread due to diffraction becomes significant. With 6.7 GW of transmitted power at 2.45 GHz, ~790 MW ends up in the side lobes[0]. So it is reason
92.
by gene-h 4y ago
One of the biggest issues with space based solar power(SBSP) is RF interference. In order for SBSP to be used for baseload power, you need to be able to beam power through clouds which means transmitting in the sub-10 GHz range. Unfortunate
93.
by gene-h 4y ago
A far more 'sensible' approach to rapid tunnel construction was experimentally tested in the 70s. The Rapid Excavation And Mining(REAM) project showed how high speed kinetic projectiles could be used to to rapidly fracture rock to
94.
by gene-h 4y ago
The soviets did something of almost the same level of sanity, they used rockets to dig holes rapidly.[0] An underground rocket is basically a specialized rocket nozzle pointed straight at the ground, the hot fast moving exhaust gases are ab
95.
by gene-h 4y ago
This 'nonsense' seems a lot more feasible now. We are now able to direct the formation of covalent bonds between two molecules using an atomic force microscope to position said molecules close to each other such that a reaction oc
96.
by gene-h 4y ago
"During the 2021 Uri storm, Texas’s $66 billion in renewable energy investments failed to perform in a time of crisis" So did nuclear. A nuclear reactor in texas went offline for two days during the crisis due to cold weather taki
97.
by gene-h 4y ago
Here's a link to the paper which this article is about: https://aip.scitation.org/doi/10.1063/5.0098011 Using plasmas is interesting for ISRU because they may work at Mars ambient atmospheric conditions. I&#x
98.
by gene-h 4y ago
Why stop at 80 degrees? With electric drive it's possible to do 360 degree steering[0]. [0] https://www.proteanelectric.com/technology/#protean360plus
99.
by gene-h 4y ago
This article is complete BS. The abstract of the publication does not mention hydrogen at all, and in fact concerns storage and separation of acetylene and ethylene gas, which are hydrocarbons, not hydrogen. This petrochemical storage and s
100.
by gene-h 4y ago
Had a professor who taught structural engineering and served as an expert witness, he said we'd better pay attention in class because there's more money to be made when stuff falls down than building it up.
101.
by gene-h 4y ago
Now make it able to work directly on visible light or at least the output of an image intensifier and you can make some pretty fast killer drones.
102.
by gene-h 5y ago
VRML is still used today. Some 3d printers take in VRML as file format, because unlike STL you can specify different colors and materials.[0][1] It's the only open multimaterial format said machines accept. [0] https://www.sm
103.
by gene-h 5y ago
This would be interesting for powering spacecraft because it doesn't have any moving parts. For the most part, spacecraft are not serviced ever, so it's best to minimize things that can break. Nuclear powered spacecraft have been
104.
by gene-h 5y ago
the cat righting maneuver is a zero-angular momentum maneuver, so if the cat has a slight amount of spin, it is not possible for the cat to correct it. That may be what happens in the video
105.
by gene-h 5y ago
it's cool, but the problem with previous graphene transistors is that they didn't really have a bandgap, meaning there wasn't much of a difference between on and off, making them unsuitable for use in computers. It looks like
106.
by gene-h 5y ago
High tech electronics can be quite sensitive to small contaminants in manufacturing equipment. A plant making HDDs accidentally lubricated some of the machinery with silicone which turned out to be very bad. This silicone got into the disks
107.
by gene-h 5y ago
Controlling the transistor requires an intermediate step converting the sound to heat. In my book, this isn't really an 'acoustic' transistor. Phononic transistors have been proposed though[0]. Phononic transistors have been
108.
by gene-h 5y ago
Hydraulic intensifiers can act as an analog of an electrical transformer. An intensifier is a hydraulic device where a large area piston is coupled to a small area piston. They are often used in water jet cutters to produce high pressures.
109.
by gene-h 5y ago
If this does indeed take off, we may expect the next trend in fashion to be clothing with with stripes and other features that fluoresce under said UVC light.
110.
by gene-h 5y ago
As the saying goes, "the marvel is not that the bear dances well, but that the bear dances at all." Bussard ramjets were previously thought not to be feasible at all.[0] Feasible, but ridiculous is a big step up from not feasible.
111.
by gene-h 5y ago
one of the largest threats from GPS getting taken out is that banks, stock exchanges[0], and even ATMs rely on GPS for timing signals. If GPS is taken out, these could stop working dealing immediate damage to the economy. [0] https:/&#
112.
by gene-h 5y ago
The article directly mentions missiles and point out that it requires less delta V to deorbit a missile than to launch a missile on suborbital or orbital trajectories.
113.
by gene-h 5y ago
A big part of the cost of space missions is not making things as light as possible, but developing the scientific instruments. More upmass doesn't always make designing sensitive scientific instruments easier. If said scientific instru
114.
Constructing covalent organic nanoarchitectures molecule by molecule via SPM(nature.com)
2 points by gene-h 5y ago|0 comments
115.
by gene-h 5y ago
Better math and even computation doesn't necessarily help in some cases. Take for instance the problem of making better solar cells and batteries. We can't necessarily make a mathematical model useful for understanding the process
116.
by gene-h 5y ago
This report found that ICF could reach LCOE as low as $25/MWh "with optimistic but not obviously unrealistic inputs."[0] This does require hohlraums cost about $2 each and are fired every 20 seconds. With mass production and
117.
by gene-h 5y ago
this uses inertial confinement rather than magnetic confinement.
118.
by gene-h 5y ago
What's important here is that they may have achieved ignition, that is making the fusion reaction self sustaining[0]. Once it becomes self sustaining one should be able to add more fuel to the pellet to get more energy out for the same
119.
by gene-h 5y ago
This work used regular cameras to see through brick and concrete block walls.
120.
by gene-h 5y ago
And the actual work including papers and video is here: http://wallcamera.csail.mit.edu/ I still don't understand how they're able to get a detectable optical signal through brick and concrete walls. It'd be

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