Engineering

547 Articles

Hacker Tactic: Building Blocks

October 24, 2024 by 11 Comments

The software and hardware worlds have overlaps, and it’s worth looking over the fence to see if there’s anything you missed. You might’ve already noticed that we hackers use PCB modules and devboards in the same way that programmers might use libraries and frameworks. You’ll find way more parallels if you think about it.

Building blocks are about belonging to a community, being able to draw from it. Sometimes it’s a community of one, but you might just find that building blocks help you reach other people easily, touching upon common elements between projects that both you and some other hacker might be planning out. With every building block, you make your or someone else’s next project quicker, and maybe you make it possible.

Sometimes, however, building blocks are about being lazy.

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Mining And Refining: Mine Dewatering

October 17, 2024 by 8 Comments

From space, the most striking feature of our Pale Blue Dot is exactly what makes it blue: all that water. About three-quarters of the globe is covered with liquid water, and our atmosphere is a thick gaseous soup laden with water vapor. Almost everywhere you look there’s water, and even where there’s no obvious surface water, chances are good that more water than you could use in a lifetime lies just below your feet, and accessing it could be as easy as an afternoon’s work with a shovel.

And therein lies the rub for those who delve into the Earth’s depths for the minerals and other resources we need to function as a society — if you dig deep enough, water is going to become a problem. The Earth’s crust holds something like 44 million cubic kilometers of largely hidden water, and it doesn’t take much to release it from the geological structures holding it back and restricting its flow. One simple mineshaft chasing a coal seam or a shaft dug in the wrong place, and suddenly all the hard-won workings are nothing but flooded holes in the ground. Add to that the enormous open-pit mines dotting the surface of the planet that resemble nothing so much as empty lakes waiting to fill back up with water if given a chance, and the scale of the problem water presents to mining operations becomes clear.

Dewatering mines is a complex engineering problem, one that intersects and overlaps multiple fields of expertise. Geotechnical engineers work alongside mining engineers, hydrogeologists, and environmental engineers to devise cost-effective ways to control the flow of water into mines, redirect it when they can, and remove it when there’s no alternative.

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Mining And Refining: Lead, Silver, And Zinc

October 2, 2024 by 16 Comments

If you are in need of a lesson on just how much things have changed in the last 60 years, an anecdote from my childhood might suffice. My grandfather was a junk man, augmenting the income from his regular job by collecting scrap metal and selling it to metal recyclers. He knew the current scrap value of every common metal, and his garage and yard were stuffed with barrels of steel shavings, old brake drums and rotors, and miles of copper wire.

But his most valuable scrap was lead, specifically the weights used to balance car wheels, which he’d buy as waste from tire shops. The weights had spring steel clips that had to be removed before the scrap dealers would take them, which my grandfather did by melting them in a big cauldron over a propane burner in the garage. I clearly remember hanging out with him during his “melts,” fascinated by the flames and simmering pools of molten lead, completely unconcerned by the potential danger of the situation.

Fast forward a few too many decades and in an ironic twist I find myself living very close to the place where all that lead probably came from, a place that was also blissfully unconcerned by the toxic consequences of pulling this valuable industrial metal from tunnels burrowed deep into the Bitterroot Mountains. It didn’t help that the lead-bearing ores also happened to be especially rich in other metals including zinc and copper. But the real prize was silver, present in such abundance that the most productive silver mine in the world was once located in a place that is known as “Silver Valley” to this day. Together, these three metals made fortunes for North Idaho, with unfortunate side effects from the mining and refining processes used to win them from the mountains.

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Fukushima Daiichi: Cleaning Up After A Nuclear Accident

September 23, 2024 by 47 Comments

On 11 March, 2011, a massive magnitude 9.1 earthquake shook the west coast of Japan, with the epicenter located at a shallow depth of 32 km,  a mere 72 km off the coast of Oshika Peninsula, of the Touhoku region. Following this earthquake, an equally massive tsunami made its way towards Japan’s eastern shores, flooding many kilometers inland. Over 20,000 people were killed by the tsunami and earthquake, thousands of whom were dragged into the ocean when the tsunami retreated. This Touhoku earthquake was the most devastating in Japan’s history, both in human and economic cost, but also in the effect it had on one of Japan’s nuclear power plants: the six-unit Fukushima Daiichi plant.

In the subsequent Investigation Commission report by the Japanese Diet, a lack of safety culture at the plant’s owner (TEPCO) was noted, along with significant corruption and poor emergency preparation, all of which resulted in the preventable meltdown of three of the plant’s reactors and a botched evacuation. Although afterwards TEPCO was nationalized, and a new nuclear regulatory body established, this still left Japan with the daunting task of cleaning up the damaged Fukushima Daiichi nuclear plant.

Removal of the damaged fuel rods is the biggest priority, as this will take care of the main radiation hazard. This year TEPCO has begun work on removing the damaged fuel inside the cores, the outcome of which will set the pace for the rest of the clean-up.

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A Field Guide To The North American Substation

August 22, 2024 by 15 Comments

Drive along nearly any major road in the United States and it won’t be long before you see evidence of the electrical grid. Whether it’s wooden poles strung along the right of way or a line of transmission towers marching across the countryside in the distance, signs of the grid are never far from view but often go ignored, blending into the infrastructure background and becoming one with the noise of our built environment.

But there’s one part of the electrical grid that, despite being more widely distributed and often relegated to locations off the beaten path, is hard to ignore. It’s the electrical substation, more than 55,000 of which dot the landscape of the US alone. They’re part of a continent-spanning machine that operates as one to move electricity from where it’s produced to where it’s consumed, all within the same instant of time. These monuments of galvanized steel are filled with strange, humming equipment of inscrutable purpose, seemingly operating without direct human intervention. But if you look carefully, there’s a lot of fascinating engineering going on behind those chain-link fences with the forbidding signage, and the arrangement of equipment within them tells an interesting story about how the electrical grid works, and what the consequences are when it doesn’t.

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Undersea Cable Repair

July 30, 2024 by 6 Comments

The bottom of the sea is a mysterious and inaccessible place, and anything unfortunate enough to slip beneath the waves and into the briny depths might as well be on the Moon. But the bottom of the sea really isn’t all that far away. The average depth of the ocean is only about 3,600 meters, and even at its deepest, the bottom is only about 10 kilometers away, a distance almost anyone could walk in a couple of hours.

Of course, the problem is that the walk would be straight down into one of the most inhospitable environments our planet has to offer. Despite its harshness, that environment is home to hundreds of undersea cables, all of which are subject to wear and tear through accidents and natural causes. Fixing broken undersea cables quickly and efficiently is a highly specialized field, one that takes a lot of interesting engineering and some clever hacks to pull off.

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AMD Returns To 1996 With Zen 5’s Two-Block Ahead Branch Predictor

July 28, 2024 by 14 Comments

An interesting finding in fields like computer science is that much of what is advertised as new and innovative was actually pilfered from old research papers submitted to ACM and others. Which is not to say that this is necessarily a bad thing, as many of such ideas were not practical at the time. Case in point the new branch predictor in AMD’s Zen 5 CPU architecture, whose two-block ahead design is based on an idea coined a few decades ago. The details are laid out by [George Cozma] and [Camacho] in a recent article, which follows on a recent interview that [George] did with AMD’s [Mike Clark].

The 1996 ACM paper by [André Seznec] and colleagues titled “Multiple-block ahead branch predictors” is a good start before diving into [George]’s article, as it will help to make sense of many of the details. The reason for improving the branch prediction in CPUs is fairly self-evident, as today’s heavily pipelined, superscalar CPUs rely heavily on branch prediction and speculative execution to get around the glacial speeds of system memory once past the CPU’s speediest caches. While predicting the next instruction block after a branch is commonly done already, this two-block ahead approach as suggested also predicts the next instruction block after the first predicted one.

Perhaps unsurprisingly, this multi-block ahead branch predictor by itself isn’t the hard part, but making it all fit in the hardware is. As described in the paper by [Seznec] et al., the relevant components are now dual-ported, allowing for three prediction windows. Theoretically this should result in a significant boost in IPC and could mean that more CPU manufacturers will be looking at adding such multi-block branch prediction to their designs. We will just have to see how Zen 5 works once released into the wild.