Intuition About Maxwell’s Equations

November 13, 2024 by Al Williams 13 Comments

You don’t have to know how a car engine works to drive a car — but you can bet all the drivers in the Indy 500 have a better than average understanding of what’s going on under the hood. All of our understanding of electronics hinges on Maxwell’s equations, but not many people know them. Even fewer have an intuitive feel for the equations, and [Ali] wants to help you with that. Of course, Maxwell’s gets into some hairy math, but [Ali] covers each law in a very pragmatic way, as you can see in the video below.

While the video explains the math simply, you’ll get more out of it if you understand vectors and derivatives. But even if you don’t, the explanations provide a lot of practical understanding

Understanding the divergence and curl operators is one key to Maxwell’s equations. While this video does give a quick explanation, [3Blue1Brown] has a very detailed video on just that topic. It also touches on Maxwell’s equations if you want some reinforcement and pretty graphics.

Maxwell’s equations can be very artistic. This is one of those topics where math, science, art, and history all blend together.

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Making Art With Maxwell’s Equations

July 17, 2024 by Lewin Day 5 Comments

When you think of art, you might think of portraiture, landscapes, or other kinds of paintings. But mathematics can feel artistic at times, too. We’ve all seen gorgeous Mandelbrot fractals, and less gorgeous Julia fractals, but that’s not all that’s out there. As [Prof. Halim Boutayeb] demonstrates, Maxwell’s equations can show us some real beauty, too.

The work involves running simulations of multiple electromagnetic sources moving, bouncing around, interacting, and so on. The art comes in the plotting of the fields, in warm colors or just outright rainbows. The professor does a great job of pairing some of these videos with pumping electronic music, which only adds to the fun.

Of course, the colors are pretty, but there’s a lot of valuable physics going on behind all this. Thankfully, there are all kinds of additional resources linked for those eager to learn about the Finite Difference Time Domain method and how it can be used for valid simulation tasks.

Throw this kind of stuff on a projector at your next rave and you will not be disappointed. Video after the break.

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Two Perspectives On James Clerk Maxwell And His Equations

March 26, 2020 by Al Williams 30 Comments

We are unabashed fans of [The History Guy’s] YouTube channel, although his history videos aren’t always about technology, and even when they are, they don’t always dig into the depths that we’d like to see. That’s understandable since the channel is a general interest channel. However, for this piece on James Clerk Maxwell, he brought in [Arvin Ash] to handle the science side. While [The History Guy] talked about Maxwell’s life and contributions, [Arvin] has a complementary video covering the math behind the equations. You can see both videos below.

Of course, if you’ve done electronics for long, you probably know at least something about Maxwell’s equations. They unified electricity and magnetism and Einstein credited them with spurring one of his most famous theories.

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Tesla Eyes Ultracapacitor Future With Maxwell Acquisition

February 4, 2019 by Brian Benchoff 29 Comments

As reported by Bloomberg, Tesla has acquired the innovative energy storage company Maxwell Technologies for $218 Million. The move is a direct departure from Tesla’s current energy storage requirements; instead of relying on lithium battery technology, this acquisition could signal a change to capacitor technology.

The key selling point of capacitors, either of the super- or ultra- variety, is the much shorter charge and discharge rates. Where a supercapacitor can be used to weld metal by simply shorting the terminals (don’t do that, by the way), battery technology hasn’t yet caught up. You can only charge batteries at a specific rate, and you can only discharge them at a specific rate. The acquisition of an ultracapacitor manufacturer opens the possibility of these powerhouses finding their way into electric vehicles.

While there is a single problem with super- and ultra-capacitors — the sheer volume and the fact that a module of ultracaps will hold much less energy than a module of batteries of the same size — the best guess is that Tesla won’t be replacing all their batteries with caps in the short-term. Analysts think that future Teslas may feature a ‘co-battery’ of sorts, allowing for fast charging and discharging through a series of ultracapacitors, with the main energy storage in the car still being the lithium battery modules. This will be especially useful for regenerative braking, as slowing down a three thousand pound vehicle produces a lot of energy, and Tesla’s current battery technology can’t soak all of it up.

This Week In Security: ClamAV, The AMD Leak, And The Unencrypted Power Grid

January 24, 2025 by Jonathan Bennett 10 Comments

Cisco’s ClamAV has a heap-based buffer overflow in its OLE2 file scanning. That’s a big deal, because ClamAV is used to scan file attachments on incoming emails. All it takes to trigger the vulnerability is to send a malicious file through an email system that uses ClamAV.

The exact vulnerability is a string termination check that can fail to trigger, leading to a buffer over-read. That’s a lot better than a buffer overflow while writing to memory. That detail is why this vulnerability is strictly a Denial of Service problem. The memory read results in process termination, presumably a segfault for reading protected memory. There are Proof of Concepts (PoCs) available, but so far no reports of the vulnerability being used in the wild.
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This Week In Security: Recall, BadRAM, And OpenWRT

December 13, 2024 by Jonathan Bennett 6 Comments

Microsoft’s Recall feature is back. You may remember our coverage of the new AI feature back in June, but for the uninitiated, it was a creepy security trainwreck. The idea is that Windows will take screenshots of whatever is on the screen every few seconds, and use AI to index the screenshots for easier searching. The only real security win at the time was that Microsoft managed to do all the processing on the local machine, instead of uploading them to the cloud. All the images and index data was available unencrypted on the hard drive, and there weren’t any protections for sensitive data.

Things are admittedly better now, but not perfect. The recall screenshots and database is no longer trivially opened by any user on the machine, and Windows prompts the user to set up and authenticate with Windows Hello before using Recall. [Avram] from Tom’s Hardware did some interesting testing on the sensitive information filter, and found that it worked… sometimes.

So, with the public preview of Recall, is it still creepy? Yes. Is it still a security trainwreck? It appears that the security issues are much improved. Time will tell if a researcher discovers a way to decrypt the Recall data outside of the Recall app.

Patch Tuesday

Since we’re talking about Microsoft, this week was Patch Tuesday, and we had seventy-one separate vulnerabilities fixed, with one of those being a zero-day that was used in real-world attacks. CVE-2024-49138 doesn’t seem to have a lot of information published yet. We know it’s a Heap-based Buffer Overflow in the Common Log File driver, and allows an escalation of privilege to SYSTEM on Windows machines. Continue reading “This Week In Security: Recall, BadRAM, And OpenWRT” →

Hackaday Links: April 21, 2024

April 21, 2024 by Dan Maloney 12 Comments

Do humanoid robots dream of electric retirement? Who knows, but maybe we can ask Boston Dynamics’ Atlas HD, which was officially retired this week. The humanoid robot, notable for its warehouse Parkour and sweet dance moves, never went into production, at least not as far as we know. Atlas always seemed like it was intended to be an R&D platform, to see what was possible for a humanoid robot, and in that way it had a heck of a career. But it’s probably a good thing that fleets of Atlas robots aren’t wandering around shop floors or serving drinks, especially given the number of hydraulic blowouts the robot suffered. That also seems to be one of the lessons Boston Dynamics learned, since Atlas’ younger, nimbler replacement is said to be all-electric. From the thumbnail, the new kid already seems pretty scarred and battered, so here’s hoping we get to see some all-electric robot fails soon.

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