Work/worked for a place that was doing this. There's a couple problems:
* More battery weight means less cargo weight
* Trailers are dumb; the standard hookup (in NA) is lights and air. I hear CAN is common in EU though.
* Trailers are cheap and almost disposable.
The trucking industry is very slow moving, and probably 20 years behind passenger cars. So changing any of this stuff, even though none of it sounds particularly major, is at least 15 years out to start. Then you're left with the hundreds of thousands of "legacy" trailers that need to be retired or retrofit. The tractor to trailer ratio out there is like 1:10.
One interesting use case for this though is refrigerated (refer) trailers. They're often diesel-electric so they can plug in to shore power. Add a battery to this and maybe you can dump the diesel motor. Again though, weight is an issue... diesel is an order of magnitude more energy dense than the best batteries we have.
Voltage spikes from line inductance, voltage drop-outs from line resistance. Basically you have little reservoirs of charge scattered all around the board (current flow isn't instantaneous in a real circuit).
It helps to always think of current draw in a compete loop, out the "top" of the capacitor, through your IC, and back into the ground side (this isn't necessarily what's happening physically). Shorter loop means less inductance, shorter traces less resistance.
Decoupling can be used on signal lines, but we’re talking about power lines here. If you have something like an ATMega, it will change its power demands very frequently at high frequencies due to switching signals on and off. Without some additional capacitance on the board, the inductance will dominate at high frequencies. Inductance resists change in current, and you’ll get voltage drops.
Capacitance is in many ways the opposite of inductance. If you place capacitors close to the power sink (e.g. the ATMega), the traces will have lower inductance and be “decoupled” from the power supply.
Commercial drivers are involved in collisions less frequently, and the more stringent licensing requirements (i.e. a law) are probably helping with that.
Drivers knowing that they will get away with mowing down a pedestrian so long as they say they didn't see them is also going to encourage dangerous driving.
Most importantly, laws that promote safer street designs make a massive difference in pedestrian fatalities.
All this to say that: laws do protect people from 2ton hunks of steel.
> Drivers knowing that they will get away with mowing down a pedestrian so long as they say they didn't see them is also going to encourage dangerous driving.
This is silly. Nobody thinks this. ”Mowing down a pedestrian”, even if one has a perfect legal defense, would be incredibly traumatic even for the driver. Traffic rules ought to be engineered with practicality (physics, the limits of human cognition and visual perception, etc.) paramount.
> I thought it is pretty well accepted there isn't a "gravaton" like there are photons.
Different branch of physics that we can't quite mesh with GR yet. A graviton is the quantized "piece" of gravity, like phonon is for sound/mechanical waves, or photons for EM. It exists as much as a photon or any other "messenger particles" exists, in that it's a useful mathematical model. It's not something we have isolated/observed with equipment though.
Yes I was shocked that the lady behind the podium stated “now look here” as if it is totally normal. They’ve clearly been instructed to do this. And it makes it all the more alarming that this power is vested in the government. They can abuse this ability to introduce new dystopian things in many other settings that are more consequential.
Meh you don't need a PE to be an engineer. That's stretching the gatekeeping too far. PE is valuable for a lot of things, but not necessary for a lot of actual engineering work. Is a trained and working electrical engineer not an engineer because a PE isn't necessary to design and build sensors, loggers, etc?
PE essentially just means you can legally sign off on safety critical designs. Engineering is the application of math and physics to solve a problem.
Anecdotally, the handful of PEs I know are the pencil-pusher types. They're engineers on paper, but a critical skill for engineering is actually building stuff.
I mean, if someone answers 'no, got a couple years before I'm eligible', or 'no, I don't need it for this line of work', you still probably got an idea of whether this person works in an engineering discipline.
* More battery weight means less cargo weight
* Trailers are dumb; the standard hookup (in NA) is lights and air. I hear CAN is common in EU though.
* Trailers are cheap and almost disposable.
The trucking industry is very slow moving, and probably 20 years behind passenger cars. So changing any of this stuff, even though none of it sounds particularly major, is at least 15 years out to start. Then you're left with the hundreds of thousands of "legacy" trailers that need to be retired or retrofit. The tractor to trailer ratio out there is like 1:10.
One interesting use case for this though is refrigerated (refer) trailers. They're often diesel-electric so they can plug in to shore power. Add a battery to this and maybe you can dump the diesel motor. Again though, weight is an issue... diesel is an order of magnitude more energy dense than the best batteries we have.
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