The second I heard that engine fire it was 1986 in my brain again. I could smell the fuel and feel the finger damage from repeatedly trying to get the darned thing to start. Followed by damage on the other side of the finger when it actually did. Ouch.
...some mockingly asking whether the firm would've maintained the same tenacity and reimbursed the Intern had he been fined 50,000 RMB at the event instead
It seemed like the future was all cloud but this year's exhibit hall was packed with infrastructure suppliers. Every third booth seemed to feature valves, pumps, massive high density power distribution systems and all the stuff you would need to cram a megawatt of electrical power into the smallest space possible and then extract the heat. Most notable to me is the waterless phase-change heat extraction provided by https://zutacore.com/. Their technology avoids massive water consumption and provides a high temperature heat source that is immediately useful for campus heating or co-generation.
Visiting Bletchley Park and seeing step-by-step telephone switching equipment repurposed for computing re-enforced my appreciation for the brilliance of the telecommunication systems we created in the past 150 years. Packet switching was inevitable and IP everything makes sense in today's world, but something was lost in that transition too. I am glad to see that enthusiasts with the will and means are working to preserve some of that history. -Posted from SC2025-
I wanted to learn more about computer hardware in college so I took a class called "Cybernetics" (taught by D. Huffman). I thought we were going to focus on modern stuff, but instead, it was a tour of information theory- which included various mathematical routing concepts (kissing spheres/spherical code, Karnaugh maps). At the time I thought it was boring, but a couple decades later, when working on Clos topologies, it came in handy.
Other interesting notes: the invention of telegraphy and improvements to the underlying electrical systems really helped me understand communications in the 1800s better. And reading/watching Cuckoo's Egg (with the german relay-based telephones) made me appreciate modern digital transistor-based systems.
Even today, when I work on electrical projects in my garage, I am absolutely blown away with how much people could do with limited understanding and technology 100+ years ago compared to what I'm able to cobble together. I know Newton said he saw farther by standing on the shoulders of giants, but some days I feel like I'm standing on a giant, looking backwards and thinking "I am not worthy".
When the Bell System broke up, the old guys wrote a 3-volume technical history of the Bell System.[1] So all that is well documented.
The history of automatic telephony in the Bell System is roughly:
- Step by step switches. 1920s Very reliable in terms of failure, but about 1% misdirected or failed calls. Totally distributed. You could remove any switch, and all it would do is reduce the capacity of the system slightly. Too much hardware per line.
- Panel. 1930s. Scaled better, to large-city central offices. Less hardware per line.
Beginnings of common control. Too complex mechanically. Lots of driveshafts, motors, and clutches.
- Crossbar. 1940s. #5 crossbar was a big dumb switch fabric controlled by a distributed set of microservices, all built from relays. Most elegant architecture. All reliable wire relays, no more motors and gears. If you have to design high-reliability systems, is worth knowing how #5 crossbar worked.
- 1ESS - first US electronic switching. 1960s Two mainframe computers (one spare) controlling a big dumb switch fabric. Worked, but clunky.
- 5ESS - good US electronic switching. Two or more minicomputers controlling a big dumb switch fabric. Very good.
The Museum of Communications in Seattle has step by step, panel, and crossbar systems all working and interconnected.
In the entire history of electromechanical switching in the Bell System, no central office was ever fully down for more than 30 minutes for any reason other than a natural disaster, and in one case a fire in the cable plant. That record has not been maintained in the computer era. It is worth understanding why.
The more I study the 5E I see it as a multicomputer or distributed system. The minicomputers were responsible for OAM and orchestrating the symphony over time, but the communications are happening across the CM which implements the Time/Space/Time fabric and a sea of microcontrollers. I think this clarification is worthwhile because it drives your point about faults in this computer-era and by extension this (micro)services-era home even more -- it's much less mainframe and more distributed system than commonly chronicled, which can be a harder problem especially with the tooling back then.
The big dumb switch fabric of #5 Crossbar has no processing power at all, but it has persistent state. The units that have processing power all go down to their ground state at the end of each call processing event, and have no state that persists over transactions. The various processing units (markers, junctors, senders, originating registers, etc.) are all at least duplicated, and usually there's a pool of them. Requests "seize" a unit at random from a pool, the unit does its thing, and the unit is quickly released.
Units have self-checking, and if they fail, they drop out of their pool and raise an alarm. The call capacity or connection speed of the exchange is reduced but it keeps working. Everything has short hardware stall timers which will prevent some unit failure from hanging the exchange.
#5 Crossbar has almost no persistent memory. End offices (for connecting subscriber lines) did not log call info. Toll offices did, but that used an output-only paper tape punch. There's so little state in the switch that matching up call start and call end events was done later in a billing office where the paper tape was read.
The combination of statelessness and resource pools prevented total failure. Errors and unit failures happened occasionally but could not take down the whole switch.
There's plenty of info about #5 Crossbar on line, but 1950s telephony jargon is so different from 2020s server jargon that it's not obvious that #5 Crossbar is a microservices architecture.
The Microcenter in Cambridge (MA) finally updated their sign to modernize the rainbow Apple logo a few years ago. I hope it's stashed somewhere, to me it's more iconic than the Citgo sign a few miles away. They have added some components and kits but it doesn't fill the yawning void left by You-Do-It Electronics shutting down a year ago, or Radio Shack's slow motion demise.
I just added strips of fake fur to the straps my boring old helmet to diffuse the wind noise the same way a "dead cat" cover on a microphone does. They look a bit like muttonchops which is a bonus as far as I am concerned. I use wraparound bone conduction headphones that don't block my ears. I would be afraid of losing an expensive earbud.
$4500 is ten or more of my homebrew 750 watt electric mountain bike originally built in 2004. I just repowered with LiFePO4 after 10 years in storage and the new batteries really pull. It has a front hub motor with a throttle control limited to 20 mph. My commute is 10 miles, 6 on a dedicated bike path. Life is good.
Those are high performance mountain bikes with carbon fiber frames, top of the line components, carbon wheels. This is an aluminum city commuter and 4.5k is at the high end of that class of ebike.
the problem with $5-$15k bikes is you can't actually use them in the USA as they'll be stolen. You can commute if you have the place to keep it secure. You can not stop for some shopping on the way home though as you'll lose your bike.
The last bike I had stolen was one I paid $100 for.
If I commuted via bicycle in an area with frequent larceny, I’d simply take it inside to my cubicle, which is surprisingly easy. Currently I live in a low larceny area so I simply leave it outside of the office, unlocked.
My $200 rusty ebike has been parked outside for 18 months in central London without problems. I take the battery in. The homeless junkie would have to get an angle grinder to cut two D locks, figure out how to buy the battery which costs $300 and is only available from decathlon, somehow try to make a profit out of the whole operation which I don't think I could myself and so on.
It's actually cost me about another $500 in maintenance getting the various bits that pack up replaced but it's a good theft deterrent.
I guess it varies by location but we have homeless druggies and bike thieves here too. I think old rusty stuff not being very attractive to thieves is fairly universal.
You might have different problems but you don't have the American problem with bike theft. Homeless here steal bikes regardless of their price and condition.
Right, the thieves will shoulder surf or pick a lock to get into the "secure" office building storage area. Happens all the time and the police won't bother to investigate.
What kind of capacity from your LFP battery? Is it diy built?
I did one in the spring 16S with 25Ah cells and it's been amazing since. Only problem is it's a bit too big to fit anywhere I'd like it to. I have to mount it on a rear rack
I am using 3x 12v 185wh batteries in series. Realistically I can count on around 500wh. They are only 3 lbs each and fit neatly within the frame of the mtb. I don't like having them up on the rear rack, they tend to make the tail of the bike wag a bit compared to low and centered.
I have a big commute and in the (Canadian) winter my old 750Wh was sometimes not up to the task. So I went wildly over the top and built a huge cap battery. I never need to worry now
Sure if you can't DIY. It's a 20 year old Fuji chromoly-frame mountain bike with Shimano components. My biggest expense was new batteries, followed by heavy duty e-bike brake pads. What did you pay to build yours?
There are two distinct use cases spelled out in this article. Electronic and photonic technology incorporating graphene to improve performance and efficiency and "we added graphene to stuff". Graphene cement, graphene carbon fibre - 3000 tons of graphene expected from one company in 2026.
Try not to breathe any, studies are still pending but that stuff gets everywhere.
100 years ago, asbestos was the new wonder material, and "We added asbestos to stuff" was a very common marketing bullet point for building materials. It found its way into flooring, mastic, the predecessors to drywall, ceiling texture, insulation, and anything and everything used near a combustion appliance.
Literally just, take a process that used to use sand or horsehair or whatever filler, and add a significant portion by mass of asbestos powder instead.
I’m not sure if it’s still the case but I searched of alibaba once and found huge rolls of asbestos for sale and massive supply capacity numbers. It was pretty shocking.
It's still used in the industry. And it can be used safely, as long as you follow the precautions (handling, encapsulation) and mind the lifecycle. But China being China? Haha no.
The R-value performance numbers for asbestos as building insulation are wildly divergent, but most of them aren't especially competitive with modern materials.
I'm not sure how to square that with claims like:
> With phenolic resins, asbestos products are produced which will provide insulation and retain strength when subjected to 5,000°F for periods of minutes (1 to 30 minutes) . See Figure 2.1 in which a rocket motor part is subjected to a temperature of 5,000°F. Figure 2.1. Rocket motor aft (asbestos-phenolic insulator) before and after firing at 5,000°F.
> The temperature approximately 1/8 in. from the surface exposed to 5,000°F will be approximately 200°F after 1/2 to 1 min. of exposure.
> When combined with magnesium carbonate and other similar products, heat insulators can be produced which will be useful for many years in such applications as boilers operating at temperatures from 500° to 1,200°F or 1,800°F.
We seem to use a matted "Ceramic Fiber" roll for its high-heat insulation capabilities these days, up to about 2300F-2600F depending on type. Asbestos fiber insulation seems to be good to somewhere between 1500F to 2700F depending on how you use it. Ceramic fiber is carcinogenic in a similar way to asbestos, but apparently considerably safer due to the fiber length/alignment.
>Try not to breathe any, studies are still pending but that stuff gets everywhere.
I would understand such comment in the context of carbon nanotubes or fullerenes, but graphene? Have you forgot that graphite is literally a bunch of stacked graphene?
Considering how much graphite pencils are used across the world, we would've seen hypothetical negative effects already with a high degree of confidence.
Yes, graphene production aims to produce larger sheets, but it only makes graphene less biologically active, not more.
> Considering how much graphite pencils are used across the world, we would've seen hypothetical negative effects already with a high degree of confidence.
Graphitosis is the graphite equivalent of silicosis and asbestosis so yes we’ve got plenty of evidence it’s harmful, but it’s mostly a problem with occupational exposure where large amounts of graphite dust are produced.
That might change if there’s tiny sheets of graphene flaking off everywhere from nanocoatings and it turns out to be carcinogenic for the same reason asbestos is (which isn’t out of the question given the studies on CNTs and nanotoxicity in general).
IIUC graphitosis, silicosis, and black lung require to inhale ungodly amounts of dust. It's orders of magnitude more than we can expect from flaking-based trace contamination.
Why do you expect a different result from "tiny sheets of graphene flaking off everywhere from nanocoatings" compared to the same flaking from graphite smeared across paper?
Pencil graphite breaks off in very large chunks and when you look at them in a microscope the particle size is in the micrometers. Those particles are too big to easily penetrate cells or deep tissue. You understand correctly about the dust issue.
Nanosheets are a different story and I’m worried that the graphene produced for industrial applications will be much smaller, flake off much easier in the field as distinct sheets like from abrasion, and stay airborne for longer. In that form they’re likely to behave like asbestos and the evidence is already pretty strong that they do.
If we start to have huge amounts of it spread through house objects, than yeah, we can increase people's exposure by a large multiplier and get the known harmful effects we already know about.
That said, I don't think we will ever have large amounts of it in house objects. Graphene doesn't seem to be useful that way. We may have it embedded in some material, but that will limit exposure to waste management and manufacture.
Also, differently from asbestos, graphene is not chemically stable. So very small pieces of it have a limited half-life.
Some amount of graphene gets produced naturally. Graphite mining, processing, dyes, things that use carbon black, soot, etc - monolayer carbon structures are a byproduct of all sorts of things that humans have been exposed to throughout history. Graphene can be decomposed and metabolized; asbestos cannot, it's very stable in all sorts of places where the body cannot process it.
It doesn't mean it's good - it can do damage in the time it's present in various systems in the body, but it's not going to present a chronic, persistent threat like asbestos.
Graphene oxidizes relatively easily, and is vulnerable to all sorts of chemical processes that can attack the edges, and there are all sorts of metabolic pathways that can handle degrading and eliminating carbon. Natural decomposition from graphene in degrading concrete, asphalt, building materials, etc should handle it without any significant health risks, as well.
Some amount of graphene is present in carbon black and ground charcoal that's been used for tattoos for at least 8,000 years (Ötzi had some pretty cool tats) and hasn't presented any significant health threats.
Don't go around inhaling graphene flakes, wear sensible PPE when handling it. Acute exposure is already known to be unhealthy. That said, carbon is processed pretty well by a multitude of organisms and natural chemical processes, making the risk of chronic graphene contamination fairly low. It's a different order of hazard than asbestos entirely, and by all the evidence available so far, carbon fibers are going to be the more dangerous material.
