Raise your hand if you remember when PulseAudio was famous for breaking audio on Linux for everyone. For quite a few years, the standard answer for any audio problem on Linux was to uninstall PulseAudio, and just use ALSA. It’s probably the case that a number of distros switched to Pulse before it was quite ready. My experience was that after a couple years of fixing bugs, the experience got to be quite stable and useful. PulseAudio brought some really nice features to Linux, like moving sound streams between devices and dynamically resampling streams as needed.
You don’t often turn on a light and think, “That power company is sure on the ball!” You generally only think of them when the lights go out without warning. I think the same is true of search. You don’t use Google or DuckDuckGo or any of the other search engines and think “Wow! How awesome it is to have this much information at your fingertips.” Well. Maybe a little, but it is hard to remember just how hard it was to get at information in the pre-search-engine age.
I were thinking about this the other day when I read that Ruth Freitag had died last year. Ruth had the unglamorous but very important title of reference librarian. But she wasn’t just an ordinary librarian. She worked for the Library of Congress and was famous in certain circles, counting among her admirers Isaac Asimov and Carl Sagan.
Ruth Freitag in 1985
You might wonder why a reference librarian would have fans. Turns out, high-powered librarians do more than just find books on the shelves for you. They produced bibliographies. If you wanted to know about, say, Halley’s comet today, you’d just do a Google search. Even if you wanted to find physical books, there are plenty of places to search: Google Books, online bookstores, and so on. But in the 1970s your options were much more limited.
Turns out, Ruth had an interest and expertise in astronomy, but she also had a keen knowledge of science and technology in general. By assembling comprehensive annotated bibliographies she could point people like Asimov and Sagan to the books they needed just like we would use Google, today.
Land speed racing is one of the oldest forms of motorsport, and quite literally consists of going very, very fast in (ideally) a straight line. The higher the speed your car can attain, the better! It’s about the pure pursuit of top speed above all else, and building a car to compete is a calling for a dedicated few. If you’d like to join them, here’s how to go about it.
Faster, Faster, Faster!
A great example of the “36HP” Volkswagen class, which challenges competitors to set land speed records using only classic VW engines, with categories for various levels of modification. Note the aero wheels and raked stance. Credit: Utah Salt Flats Racing Association
Racers often pick a record or set of records they wish to beat – for example, wanting to set the the fastest speed for a gasoline-powered, naturally-aspirated four cylinder – and build their car to that end. Alternatively, a racer might build a car with a large V8 engine, for example, to compete in one class, and then disable several cylinders on a later run to try and snatch records in lower classes as well. Continue reading “How To Get Into Cars: Land Speed Racing”→
Leprosy is a bacterial disease that affects the skin, nerves, eyes, and mucosal surfaces of the upper respiratory tract. It is transmitted via droplets and causes skin lesions and loss of sensation in these regions. Also known as Hansen’s disease after the 19th century scientist who discovered its bacterial origin, leprosy has been around since ancient times, and those afflicted have been stigmatized and outcast for just as long. For years, people were sent to live the rest of their days in leper colonies to avoid infecting others.
The common result of injecting chaulmoogra oil. Image via Stanford University
Until Alice Ball came along, the only thing that could be done for leprosy — injecting oil from the seeds of an Eastern evergreen tree — didn’t really do all that much to help. Eastern medicine has been using oil from the chaulmoogra tree since the 1300s to treat various maladies, including leprosy.
The problem is that although it somewhat effective, chaulmoogra oil is difficult to get it into the body. Ingesting it makes most people vomit. The stuff is too sticky to be applied topically to the skin, and injecting it causes the oil to clump in abscesses that make the patients’ skin look like bubble wrap.
In 1866, the Hawaiian government passed a law to quarantine people living with leprosy on the tiny island of Moloka’i. Every so often, a ferry left for the island and delivered these people to their eventual death. Most patients don’t die of leprosy, but from secondary infection or disease. By 1915, there were 1,100 people living on Moloka’i from all over the United States, and they were running out of room. Something had to be done.
Professor Alice Ball hacked the chemistry of chaulmoogra oil and made it less viscous so it could be easily injected. As a result, it was much more effective and remained the ideal treatment until the 1940s when sulfate antibiotics were discovered. So why haven’t you heard of Alice before? She died before she could publish her work, and then it was stolen by the president of her university. Now, over a century later, Alice is starting to get the recognition she deserves.
Ask any electronics hobbyist or professional what the simplest building blocks of electronic circuits are, and they’ll undoubtedly say resistors, capacitors, and inductors. Ask a mechanically-inclined person the same question about their field and the answer will probably be less straightforward. Springs would make the list for sure, but then… hmm. Maybe gears? 80/20 aluminum extrusions?
As it turns out, there are a handful of fundamental building blocks in the mechanisms world, and they’re functionally very similar, and mathematically identical, to the Big Three found in electrical engineering.
Mechanical Equivalents
Before we look at the components themselves, let’s step back a moment and think about voltage and current. Voltage is a potential difference between two points in a circuit, sometimes called electromotive force (EMF). It turns out that EMF is an apt term for it, because it is roughly analogous to, well, force. Voltage describes how “hard” electrons are being “pushed” in a circuit. In much the same vein, current describes the rate of electric charge flow. Continue reading “Building Blocks: Relating Mechanical Elements To Electronic Components”→
People are obsessed with the time and the weather. We’ve talked about the weather since we were all cave dwellers hunting with spears. But the time is a different matter. Sure, people always had the idea of the passage of time. The sun rising and setting gives a natural sense of days, but daylight and dark periods vary by the time of year and to get an accurate and linear representation of time turns out to be rather difficult. That is unless you are a Greek engineer living in Alexandria around 250 BC.
Legend has it that and engineer working in his father’s barbershop led him to discover not only the first working clock, but also the pipe organ, launching the field of pneumatics in the process. That engineer was named Ctesibius and while his story is mostly forgotten, it shows he has a place as a historical hacker.
You might think there were timekeeping devices before 250 BC, and that’s sort of true. However, the devices before Ctesibius had many limitations. For example, a sundial can tell time, but only if the sun is shining. At night or during a storm it is worthless.
The International Space Station is humanity’s most expensive gym membership.
Since the earliest days of human spaceflight, it’s been understood that longer trips away from Earth’s gravity can have a detrimental effect on an astronaut’s body. Floating weightless invariably leads to significantly reduced muscle mass in the same way that a patient’s muscles can atrophy if they spend too much time laying in bed. With no gravity to constantly fight against, an astronauts legs, back, and neck muscles will weaken from disuse in as little as a week. While this may not pose an immediate problem during spaceflight, astronauts landing back on Earth in this physically diminished state are at a higher risk of injury.
Luckily this problem can be largely mitigated with rigorous exercise, and any orbiting vessel spacious enough to hold human occupants for weeks or months will by necessity have enough internal volume to outfit it with basic exercise equipment such as a treadmill or a resistance machine. In practice, every space station since the Soviet Union’s Salyut 1 in 1971 has featured some way for its occupants to workout while in orbit. It’s no replacement for being on Earth, as astronauts still return home weaker than when they left, but it’s proven to be the most practical approach to combating the debilitating aspects of long duration spaceflight.
Early NASA concept for creating artificial gravity.
Of course, there’s an obvious problem with this: every hour spent exercising in space is an hour that could be better spent doing research or performing maintenance on the spacecraft. Given the incredible cost of not just putting a human into orbit, but keeping them there long-term, time is very literally money. Which brings us back to my original point: astronauts spending two or more hours each day on the International Space Station’s various pieces of exercise equipment just to stave off muscle loss make it the world’s most expensive gym membership.
The ideal solution, it’s been argued, is to design future spacecraft with the ability to impart some degree of artificial gravity on its passengers through centripetal force. The technique is simple enough: just rotate the craft along its axis and the crew will “stick” to the inside of the hull. Unfortunately, simulating Earth-like gravity in this way would require the vessel to either be far larger than anything humanity has ever launched into space, or rotate at a dangerously high speed. That’s a lot of risk to take on for what’s ultimately just a theory.
But a recent paper from the University of Tsukuba in Japan may represent the first real steps towards the development of practical artificial gravity systems aboard crewed spacecraft. While their study focused on mice rather than humans, the results should go a long way to codifying what until now was largely the stuff of science fiction.
