borosilicate glass

3 Articles

Homebrew PH Meter Uses Antimony Electrode

November 15, 2024 by 11 Comments

Understanding the nature of pH has bedeviled beginning (and not-so-beginning) chemistry students for nearly as long as chemistry has had students. It all seems so arbitrary, being the base-10 log of the inverse of hydrogen ion concentration and with a measurement range of 0 to 14. Add to that the electrochemical reactions needed to measure pH electronically, and it’s enough to make your head spin.

Difficulties aside, [Markus Bindhammer] decided to tackle the topic and came up with this interesting digital pH meter as a result. Measuring pH electronically is all about the electrode, or rather a pair of electrodes, one of which is a reference electrode. The potential difference between the electrodes when dipped into the solution under test correlates to the pH of the solution. [Markus] created his electrode by drawing molten antimony into a length of borosilicate glass tubing containing a solid copper wire as a terminal. The reference electrode was made from another piece of glass tubing, also with a copper terminal but filled with a saturated solution of copper(II) sulfate and plugged with a wooden skewer soaked in potassium nitrate.

In theory, this electrode system should result in a linear correlation between the pH of the test solution and the potential difference between the electrodes, easily measured with a multimeter. [Marb]’s results were a little different, though, leading him to use a microcontroller to scale the electrode output and display the pH on an OLED.

The relaxing video below shows the build process and more detail on the electrochemistry involved. It might be worth getting your head around this, since liquid metal batteries based on antimony are becoming a thing.

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The High-Tech Valor Glass Vials Used To Deliver The Coronavirus Vaccine

December 28, 2020 by 70 Comments

As the world waits for COVID-19 vaccines, some pharmaceutical companies stand armed and ready with an exciting improvement: better vials to hold the doses. Vials haven’t changed much in the last 100 years, but in 2011, Corning decided to do something about that. They started developing an alternative glass that is able to resist damage and prevent cracks. It’s called Valor glass, and it’s amazingly strong stuff. Think Gorilla glass for the medical industry.

Traditionally, pharmaceutical vials have been made from borosilicate glass, which is the same laboratory-safe material as Corning’s Pyrex. Borosilicate glass gets its strength from the addition of boron. Although borosilicate glass is pretty tough, it comes with some issues. Any type of glass is only as strong as its flaws, and borosilicate glasses are prone to some particularly strength-limiting flaws. Pharmaceutical glass must stand up to extreme temperatures, from the high heat of the vial-making process to the bitterly cold freeze-drying process and storing temperature required by the fragile viral RNA of some COVID-19 vaccines. Let’s take a look at how Valor glass vials tackle these challenges.

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Next Level Spirit Level Is On The Level

October 18, 2019 by 10 Comments

Miss your shot and scratch on the eight ball? It’s natural to blame the table for not being level so you can save face, but in all likelihood, you’re probably right. [Huygens Optics]’s father never misses a billiards shot on his home table, until one day he did. [Huygens Optics] rushed to his aid and built an extremely precise spirit level for the table so it will never happen again.

First and foremost, he had to decide how sensitive the spirit level should be. Obviously, the table should be as level as possible, though other factors like the condition of the felt will come into play as well. In doing some calculations, he found that every degree of leveling error in the table translates to several millimeters of ball unevenness and deviation, so he wanted the level to have .01 degrees of accuracy. How he manages this feat of grinding and polishing in a hobbyist workshop is all captured in the fascinating video after the break.

The level is made from two disks cut from leftover 15mm borosilicate glass. Between the disks is a 4mm cavity for the liquid (ethyl alcohol) and the air bubble to move around. To avoid introducing error with uneven adhesive application, [Huygens Optics] tried to join the disks using optical contact bonding, wherein two surfaces stick together through the magic of intermolecular forces, like the one that keeps geckos attached to vertical things. That worked quite well until he added the liquid, which broke the bond. Instead, he used a thin, UV-curable epoxy.

Getting into optics doesn’t have to cost a lot. Instead of buying or grinding lenses for experimentation, you can laser-cut lens profiles out of acrylic.

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