An ion selective electrode is tool used in analytical chemistry used to determine the concentration of a given ion in a solution.
The method can determine the concentration of one ion even if there are multiple different types of ion in the solution, although in some cases this can alter the results. This is done with the help of a selective membrane that only allows certain ions through.
One cool example application mentioned on LibreTexts[ref] is the measurement of fluorine concentration in water. They explain that fluorine is added to the drinking water supply in some countries to help protect people's teeth, and so you want to be able to measure as part of quality control to make sure it is being added in correct the quantities.
The method requires calibrating with calibrating solutions which takes one hour, but once you are calibrated you just stick the sensor into the analyte and get readings in a minute without any expendables. The membrane seems to be a bit fragile which requires care, but overall it looks like a convenient method.
Sample calibration curve for an ion selective electrode
. Source. The curve is simple and log linear, so once you have that it is easy to fit new measurements to the curve.General Principles of Ion Selective Electrodes by Jacob Stewart
. Source. Ion selective electrodes Tech Tips by Vernier
. Source. It seems like a proprietary training video given with the product that this Peruvian university decided to upload to YouTube. Heroes.
Using an Ion Selective Electrode by University of Alberta
. Source. History of molecular biology bibliography by 
Ciro Santilli 37 Updated 2025-05-29 +Created 2025-01-27
Ciro Santilli 37 Updated 2025-05-29 +Created 2025-01-27Conditional probability by Art of the Problem
. Source. Hackathons are useless.
If you have a useful project, why would you ever restrict its development to a specific timeframe and with a specific set of contributors?
Just put your project on GitHub and promote it to try and get users and contributors instead!
Instead of announcing organizing hackathons, people should just curate forums where people with similar interests can talk to one another instead, to find new projects that might interest one another.
Ciro Santilli's hardware Child bicycle trailer by Ciro Santilli 37 Updated 2025-05-29 +Created 2025-01-22
Ciro Santilli 37 Updated 2025-05-29 +Created 2025-01-22First we got a Thule Chariot Cab two seater in our hands: www.thule.com/en-bg/bike-trailers/bike-trailers-for-kids/thule-chariot-cab-_-10204021 It's humongous, double seater only. Folded: 110 x 80 x 46 cm folded, 16.5 kg.
Thule Chariot Cross double: www.thule.com/en-gb/bike-trailers/bike-trailers-for-kids/thule-chariot-cross-double-_-10202026. Folded: 87 x 80 x 37.5 cm, 14.5 kg
Thule Chariot Cross single: www.thule.com/en-gb/bike-trailers/bike-trailers-for-kids/thule-chariot-cross-single-_-10202025. Folded: 87 x 65 x 37.5 cm, 13.8 kg
Thule Chariot Courier: www.thule.com/en-si/bike-trailers/bike-trailers-for-dog-and-cargo/thule-courier-_-10102001. This seems like an older version of the Cab. Folded: 99 x 74 x 32 cm. 16kg.
Burley Honey Bee burley.com/en-in/products/honey-bee. Double only: folded: 96.3 x 74.2 x 22.6 cm. 13 kg. 500 pounds new on Amazon www.amazon.co.uk/Burley-Honey-Seat-Trailer-Stroller/dp/B0BW21V26L, a used one for sale at: www.facebook.com/marketplace/item/575427528791792/ for 125. Got my hands on a new one. Felt good. Definitely much cheaper build than the Thule Chariot Cab, but way smaller. Still a bit large for the shed, but at least it stands a chance!
Burley Bee: burley.com/en-in/products/bee. Single: folded 95.25 x 65.7 x 25.4 cm 9.8 kg. Double: folded: 10.2 kg. 95.2 x 74.6 x 26.4
Burley D'Lite X: burley.com/en-in/products/dlite-x Single: folded 91.4 x 69.9 x 38.1 cm 12.5 kg. Double: folded 94 x 79.4 x 36.2 cm 13.8 kg.
Hamax Outback: www.hamax.com/kid/bike-trailer/outback-bike-trailer-2-seats Double: 20 kg folded size: does not say.
The hole point of Intel SGX is to allow users to be certain that a certain code was executed in a remove server that they rent but don't own, like AWS. Even if AWS wanted to be malicious, they would still not be able to modify your read your input, output nor modify the program.
The way this seems to work is as follows.
Each chip has its own unique private key embedded in the chip. There is no way for software to read that private key, only the hardware can read it, and Intel does not know that private key, only the corrsponding public one. The entire safety of the system relies on this key never ever leaking to anybody, even if they have the CPU in their hands. A big question is if there are physical forensic methods, e.g. using electron microscopes, that would allow this key to be identified.
Then, using that private key, you can create enclaves.
Then, non-secure users can give inputs to that enclave, and as an output, they get not only the output result, but also a public key certificate based on the internal private key.
This certificates states:and that can then be verified online on Intel's website, since they keep a list of public keys. This service is called attestation.
So, if the certificate is verified, you can be certain that a your input was ran by a specific code.
Additionally:
- you can public key encrypt your input to the enclave with the public key, and then ask the enclave to send output back encrypted to your key. This way the hardware owner cannot read neither the input not the output
- all data stored on RAM is encrypted by the enclave, to prevent attacks that rely on using a modified RAM that logs data
Ciro Santilli believes that these tools basically solve all the brain-dead problems which newbies would ask, and easy rep seekers would reply to.
Also, because Ciro Santilli only goes for long term reputation, which often means hard questions, this shot his yearly reputation rankings up without him doing anything, because all the guys who answered easy questions were decimated.
This was followed by Stack Overflow attempting to immorally and likely illegally trying to restrict free access to its previously commendable data dumps:which people were using to train LLMs.
This can be very clearly seen by several metrics on Stack Exchange Data Explorer, e.g. Ciro Santilli noticed that very clearly at: Total reputation in Stack Overflow over time how activity has been steadily falling since 2020.
Approximate total reputation change per year on Stack Overflow
. By Ciro Santilli using gnuplot. Methodology described at: Ciro Santilliś answer to the question "Total reputation in Stack Overflow over time". The 15 year old question was then closed soon after Ciro Santilli answered it, because of course that attracted some attention to the question, which of course was off-topic.
Questions asked per month on Stack Overflow
. Source. Also announced at:Related posts:
- www.reddit.com/r/programming/comments/1592s82/the_fall_of_stack_overflow/. www.reddit.com/r/programming/comments/1592s82/comment/jte8aju/ is amazing:Well known Stack Overflow user mipadi comments:You've fallen for the common misconception that the goal of stackoverflow is helping users solve problems.When the reality is that it's actually a video game. The only players are the admins/mods, and their goal is to use their "hammers" and attempts at pedantry/nitpicking (correctness not important) to compete with each other to get the highest "close" point scores. Pew pew pew!!! Bang bang bang!!! How many points can you score today?!?!Us users are just the NPCs, there as fodder for the real players.Ciro Santilli concurs, for professional niche sites. Non-professional ones are fine.
And the niche Stack Exchange sites tend to be even worse, although I can still get a question answered after much teeth gnashing, usually.
- www.reddit.com/r/programming/comments/195ygru/stackoverflow_questions_down_66_in_2023_compared/ StackOverflow Questions Down 66% in 2023 Compared to 2020. Links to: x.com/v_lugovsky/status/1746275445228654728 "What's happening with StackOverflow?" by user Vlad
- www.reddit.com/r/computerscience/comments/1fri2jt/does_anyone_still_use_stack_overflow_or_has_the/
- observablehq.com/@ayhanfuat/the-fall-of-stack-overflow
- data.stackexchange.com/stackoverflow/query/1882511/questions-asked-per-year-on-stack-overflow#graph Questions asked per year on Stack Overflow
- news.ycombinator.com/item?id=41364798
Bibliography:
- www.quantamagazine.org/rational-or-not-this-basic-math-question-took-decades-to-answer-20250108/ Rational or Not? This Basic Math Question Took Decades to Answer (2025)
Physics is a way to predict the future by Ciro Santilli 37 Updated 2025-05-29 +Created 2025-01-21
Ciro Santilli 37 Updated 2025-05-29 +Created 2025-01-21It is quite beautiful to look at it like that.
That which previous generations would treat as magical, and divine.
We are doing better and better right now.
Of course, in a way, humans are trying and often successfully predicting certain daily aspects of the future all the time. Will this car stop if I cross the road? Will this glass break if I drop it?
But there's a beauty to the level of precision that can be achieved with physics and other natural sciences.
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