Re: OK I have some swollen LiPo packs
This is for Li-Ion. LiFePo will probably behave very differently.
186 publicly visible posts • joined 27 Sep 2009
I used to believe that until I came across this EEVBlog article where he tested fuses. Summary - they are the safety feature of last resort to blow first if there is a short circuit but don't rely on them for much else.
https://www.eevblog.com/forum/blog/eevblog-1377-the-amazing-unpredictability-of-fuses/
"I bought a very second-hand BBC Micro (a partially upgraded Model A, with at least one dodgy RAM chip!) in 1989"
I wonder if it was mine. I had one of the earliest BBC model As (I think the SN was 230 ish), I upgraded the RAM and I think the printer driver (because some things needed it despite having no printer). It also had the excellent EXMON2 ROM chip in it which I used to single step through the entire OS. Those were happy days when it was possible to know everything about how it worked.
I sold it to a school in London sometime around 1984 and replaced it with a Atari ST 1024STFM (later replaced with a Mega 4).
Collisions have happened a few times. From Wikipedia:
The 1991 collision between Kosmos 1934 and Mission-related debris (1977-062C, 13475).[1]
The 1996 collision between the French Cerise military reconnaissance satellite and debris from an Ariane rocket.
The 2009 collision between the Iridium 33 communications satellite and the derelict Russian Kosmos 2251 spacecraft, which resulted in the destruction of both satellites.
The 22 January 2013 collision between debris from Fengyun FY-1C satellite and the Russian BLITS nano-satellite.
The 22 May 2013 collision between two CubeSats, Ecuador's NEE-01 Pegaso and Argentina's CubeBug-1, and the particles of a debris cloud around a Tsyklon-3 upper stage (SCN 15890)[2] left over from the launch of Kosmos 1666.
The 18 March 2021 collision between Yunhai-1 02 and debris from the Zenit-2 rocket body that launched the Kosmos 2333 satellite (a Tselina-2 satellite) in 1996.[3]
https://en.wikipedia.org/wiki/Tartrazine
Don't know how trustworthy this is but the wikipedia article says that tartrazine causes allergic symptoms in about 1:10000 people but the other 'well known' issues are all just urban legends. It might be a case of scared because they 'read it on the internet' so it becomes true by repetition.
Icon - well he might be drinking soda.
Gemini 8 had a uncontrolled thruster burn that spun the capsule upto almost 1 rotation per second - just imagine being in this and how hard it would be to function. Neil Armstrong (pre moon) was in command and somehow managed to get thing back under control without blacking out or otherwise being disabled by the spin.
Truely the Right Stuff.
I had a set of units that came back from customers as faulty but it was very hard to reproduce. I eventually discovered that it was due to a micro crack caused by a common event on these boards that only showed up when the device was in a certain orientation. When on my desk this was not the natural orientation and it worked fine but in the machine it was at 90 degrees and the weight of the sensor opened the crack.
Caused much head scratching until I found the pattern.
I had a battery powered scope which was ideal for such things - a lovely little bit of kit. More recently I was using a big old CRT scope and got zapped from it because the earth was disconnected, I know why because when it was connected it caused other problems.
Battery power is much better than no earth.
There are going to be some interesting decisions to be made on orbits of any LPS (I vote for LPS) system as there are no radiation belts or atmosphere which gives more choices but the moon has a messy mass distribution which means that more stationkeeping tweaks are going to be required as the orbit gets lower and magnetorquers wont work so there will be a increased fuel burn to maintain orientation. I suspect the answer would be proportionally higher orbits where each one can be seen from more of the moons surface. This is good for reducing the number of satellites and improving orbital stability plus do you really need a 20 satellite fix on the moon? Being between skyscrapers is wont be a issue for a while.
Lets add some maths
Radius of Earth 6380 km
Altitude of satellite 1000 km (random guess)
Diameter of satellite 10cm=0.0001 km (thickness of shell)
Area = 4*pi*(6300+1000)^2= 7e8 km^2
Volume = 7e8 * 0.0001 = 68000 km^3
At a density of 1000 kg/m^3 = 1e12 kg/km^3 (water) this has a mass of
Mass = 68000 * 1e12 = 7e16 kg
A falcon heavy can launch about 10000 kg so to make a 10cm thick shell around Earth at a height of 1000 km would take about 7e12 launches. I think we are safe for now.
(Please check my maths)
Maybe flotsam vs jetsam is relevant here. As it was deliberatly 'thrown overboard' it would be jetsam in which case NASA no longer owns it.
https://oceanservice.noaa.gov/facts/flotsam-jetsam.html
"Under maritime law the distinction is important. Flotsam may be claimed by the original owner, whereas jetsam may be claimed as property of whoever discovers it. If the jetsam is valuable, the discoverer may collect proceeds received though the sale of the salvaged objects."
The problem is more that people believe stuff they read on the internet from sources as unreliable as social media.
Schools should have compulsory courses on critical thinking and general how to identify poor information and this should be done early, no later than 10 years old.
Won't fix it but at least it is a start
Many years ago I was on a Twin Otter fully loaded with fuel drums. We headed off on the great white expanse but we were too heavy to get off the ground. After 10 mins or so of very fast bouncing and probably skipping over many crevasses we finally limped into the air. It was the EPICA project at 2892m altitude which can't have helped. Apparently there is now a station there (Kohnen) but it my time it was in the middle of nowhere with a high snow accumulation rate.
I once built a pendulum clock from PC components. The pendulum was hanging from the head arm of a HDD and used the coils to nudge it when it slowed down. The swing was monitored by a mechanical mouse sensor that incremented the clock on every swing and measured the swing speed by looking at the time taken to traverse the mouse sensor.
All done in discrete 74xx and 4000 series logic - lots of it.
Usenet was good in the 1990s, comp. and sci. groups were my lunchtime viewing and I even used Emacs as a reader. Took a break from Usenet in the late 90s and when I looked again the signal/noise which had been deteriorating for years had dropped to the point were it was not worth the effort.
I hate to think what it is like now.
Sad that it is gone but it had no defence against spam so once the threat of your university / company taking action against you if you made a bad post was gone it was doomed.
But is it wrong? Given publically available data to it the answer to 'an average woman of Afghanistan' is basically what it produced. It is going to be a merging of the images out there and 90% of them are going to be the iconic image so it is no surprise that the result is very similar to the original image but impressively facing towards the 'camera' which puts this in a different league to a simple copy. What about the other lesser influences to this image? Where do they stand? When it comes to copyright this is a minefield.
"500v supply by putting two adjacent 240v sockets in series." - Ouch, I see exactly how the thought process of your colleague went on this because if you think about it from a certain point of view it makes sense.
Sadly from another point of view connecting the live of one socket to the neutral of another would not have the desired effect!
I have also got to wonder why anyone was trying to get 500V from the mains. Wanting double heat from a portable heater maybe?
I left nearly 2 years ago after a epic fight and I still have all my virgin media kit in a cardboard box - locked TIVO, cable modem and a few RF connectors. I have tried to contact them to get them to pick it up but it always ends up with me being asked to give a 1..10 score on how good the pick up process was and the process ends there.
I might need to take it to the local tip to get it disposed of cleanly.
We had "the phone of doom". When a machine was on a long term test someone was given this phone overnight, the closer to work you lived the more often you had to take it. If the machine went wrong the phone rang and you had to go in to fix it and start it up again.
Always a stressful night (and unpaid) but luckily I lived a hour away so only had it rarely and doom never struck me.
I still have a box of virgin media kit awaiting collection from when I cancelled back in Jan 2022. It even includes a pretty good virgin media locked tivo box.
I have tried several times to get rid of it but there is no way to contact them and every attempt just ends up with them sending me a survey asking for a 1-10 score on how well the close of contract process went.
Answer is very badly. When I tried to cancel they kept finding dodgy reasons why they could not start the cancellation process or a few more days which would have pushed me into a extra month of billing just after hugh price rise. Eventually I got them to cancel before this date but by the end their excuses were getting increasingly desperate.