When we last left off, I had just set up a new SLA resin printer and was on the verge of doing the initial round of printing to see just how resin printing in 2026 compares to way back in 2020. Surely SLA printing had to be easier and less fussy than it was in 2020?
During these weeks of printing, setting up printers and taking a gander at the various workflows that certain printers and their manufacturers try to push you into I have both produced a series of not too shabby prints and some delightful spaghetti. I also flipped a few proverbial tables and formed some strong opinions on 3D printing workflows, of which some can considered to be family-friendly.
Without further ado, let’s get into some updates, a bit of ranting, and even some printing results.
However you make a digital computer, you need something to represent a binary digit. Usually this is some form of switch: a relay, a tube, or a transistor, although there have been other ways to represent state. In 1954, [Eiichi Goto] of Japan invented the parametron, a resonant circuit using a ferrite core and a capacitor that could be moved between two phases.
According to [Goto’s] 1959 paper, the device is effectively a parametric oscillator, similar to some used at UHF frequencies by hams. The idea is that a tuned circuit is set to some frequency and driven with twice that frequency.
A What?
A parametron is essentially a resonant circuit made with inductors or capacitors whose reactance is varied at twice its resonant frequency. That “pumping” causes the circuit to oscillate at half the pump frequency. The neat trick is that there are two equally stable oscillation states at half the pump frequency, separated from each other by 180° of phase. Those two phases become binary 0 and 1. Depending on the incoming signals, one phase will win over the others.
Recently thermal power stations have been in the news quite a bit, mostly in the context of them being throttled back or shut down due to the river water used to cool them either getting too warm or said river having dropped to a level where it can no longer provide cooling water. Obviously this is a problem, but it helps to understand how we got to this point and what can be done to fix it.
Thermal power stations – also called power plants – come in a wide variety of shapes and sizes, ranging from old-school coal- and gas-fueled power stations to modern nuclear power plants. Something like a concentrated solar power (CSP) station is also a thermal power station, as all of them have a heat source that’s used to generate electricity from, whether that’s a boiler, nuclear reactor core or a big vat of sodium heated up by the Sun via massive mirrors or oil-filled tubes in parabolic throughs.
Except for open-cycle gas turbines (OCGTs) – which are basically jet engines connected to a generator – this thermal energy is then used to generate steam that drives a steam turbine. Once most energy in the steam has been depleted, it has to be condensed back into e.g. water, so that it can be led back to the steam generator. How this condensing step is performed is the question here, with a number of methods available.
Everyone talks about the weather. This is doubly true for sailors, where bad weather could mean a very bad day. So it isn’t surprising that navies around the world have had a keen interest in weather forecasting. But how did you predict the weather before modern instruments, radar, and satellite images? Vice Admiral Robert FitzRoy had great faith in “storm glasses,” a glass chamber containing some chemicals that he didn’t invent, but did document and promote heavily during the 1860s.
Did it work? Apparently not, but the device is still interesting in its own right. FitzRoy was a pioneer of meteorology, replacing folklore with actual observations and attempts at scientific rigor. While he did arm observation stations with conventional things like thermometers and barometers, he was also a proponent of the weather glass. Continue reading “FitzRoy’s Glass: Victorian Weather Marvel Or Glorified Thermometer?”→
Once upon a time, telephones were primarily point-to-point communications systems. There were options for three-way and conference calls out there, but by and large the plain old telephone system was about connecting one handset to another for a direct conversation. For this reason, the telephone was seldom used for mass emergency communications, because it was simply not fit for broadcasting a message to a wide number of people.
However, technology has since changed. Our modern phones are all connected to a big digital over-the-air network, and large swathes of them can be addressed all at once if so needed. This has led to the development of emergency warning systems that use the cellular network, with Cell Broadcast being the most notable iteration.
Trains and the railways they run on are a great way to move lots of stuff, or lots of people, a long way. Steel wheels on steel rail can shift great loads at good speeds and railways remain a backbone of logistics for this very reason. The only problem is that they require a great deal of initial investment to build and plenty of maintenance to keep them functional over time.
These concerns can make a railway a difficult proposition when it comes to getting large amounts of goods in and out of remote areas. It’s a problem that Australia faces, with settlements far off the beaten track that are nevertheless in need of high-throughput freight connections. And if you can’t go rail, you go road… in a big way.
You may have a 4K television. Perhaps you have even bought an 8K screen, despite the shortage of things worth watching in 8K. A 16K display is, today, a rarity. But even when those eventually become commonplace, yours probably will not cover 14,900 square meters, rise 73 meters into the air, or wrap over your head and behind your peripheral vision.
That is approximately what happens inside Sphere in Las Vegas. The venue’s interior display is quoted as having a resolution of 16K by 16K and an area of 160,000 square feet, or about 3.7 acres. Unlike most enormous movie screens, it is not illuminated by a projector. The entire surface is a direct-view LED display: an immense, curved video wall assembled from tens of thousands of smaller pieces.
After seeing The Wizard of Oz at Sphere, however, the most interesting part was not simply the screen’s size. It was how thoroughly the screen could disguise itself.
Where Did The Theater Go?
Radio City or the Sphere? (It is the Sphere; photo courtesy [DP])Before the presentation began, the auditorium appeared to have a conventional architectural ceiling. Great orange ribs curved over the seating, while ventilation grilles, suspended loudspeakers, lighting fixtures, curtains, and video monitors completed the illusion. It looked like the Radio City Music Hall’s proscenium. Then the show started — and the apparent theater completely disappeared. The speakers, the TVs, even the stage.
The obvious first conclusion was that the LED surface must be optically transparent, allowing the audience to see the real roof behind it until the pixels illuminated. That explanation was attractive because Sphere’s audio system really is installed behind the display, and the surface must allow sound through it.
It was also, apparently, wrong. The only explanation that makes sense is that the ceiling, ribs, grilles, speakers, and monitors were already being displayed by the screen. It was like a holodeck impersonating a physical theater interior. When the Oz material began, the system simply replaced one complete visual environment with another.
That’s what happens when a display fills nearly all of your useful visual field. A normal screen announces itself with a bezel, a wall, or at least a clearly visible edge. Sphere’s display extends upward and around the audience, removing many of those references. Give the image credible perspective, texture, shadows, and familiar architectural details, and the brain accepts the pixels as a room.
The same effect makes the Oz landscapes seem less like scenes displayed in front of the audience and more like places into which the auditorium has been inserted. Of course, there are more special effects. For The Wizard of Oz, there is wind and smoke, along with paper leaves, flower petals, and foam-rubber apples that fall from the sky. All of this makes it even more immersive.
