Tag Archives: engineering

Horizon Event: The big EHT reveal

The Event Horizon Telescope team announces its major discovery following two intense and quiet years of data analysis on top of a longer period of development.   A nice testament to aperture synthesis and international collaboration as the rest of the world spirals into madness.  Damn!!!

Youtube Channel: National Science Foundation

Context for the interested public:
Youtube Channel: Sixty Symbols

 

Scrubbing bubbles: The pros and cons of cavitation

We routinely use ultrasonic cleaners to decontaminate all kinds of surfaces.  A little solvent, some buzzing, and jewelry, electronic parts, and pen nibs get degunked effectively.  Cavitation is responsible.  It is also responsible for damaging surfaces such as ship propellers and pump impellers.  The first video explains the physical chemistry behind the process and its (mostly) destructive effects.  The second shows it applied to cleaning vegetables which, surprisingly, is a research problem funded by the National Science Foundation.  Both videos show closeups of bubble collapse making the cleaning/damage mechanism much easier to understand.

Youtube Channel: IET Institute for Energy Technology

Youtube Channel: National Science Foundation

Addendum 7 April 2019: More detailed super-slowmo  videos from the EPFL group featured in the first video.
Source: CAVITATION BUBBLES IN VARIABLE GRAVITY

Addendum 25 September 2020:  EPFL has reorganized its webpages and the cavitation videos have disappeared.  Here is an American Physical Society report on that research.

Youtube Channel: APS Physics

Maintaining standards: The triple-point cell

Our society depends on standards in countless, mostly invisible ways.   If we can’t agree on how to measure weight, length, temperature, or time we can kiss manufacturing and our manufactured world with its specified, engineered, and interchangeable parts goodbye.   Actually creating and maintaining these standards is hard and the methods change over the years.  The meter was once defined in relation to earthly distances until the realization that the earth changes over time.  Now it is defined in relation to the speed of light which we are pretty sure does not.  The second used to be defined in terms of the day, now it is based on a fundamental property of the cesium atom.  The kilogram has just been redefined in terms of Planck’s constant which then turns into a combination of the second and the meter.

Making any of these measurements is difficult and requires a lot of fancy equipment, often involving lasers, vacuum chambers, electromagnets, and/or racks of electronics.  Here’s how NIST’s new F2 atomic clock works schematically and here’s a package from its inventor on the details.   As the F2 becomes a practical albeit sophisticated standard, even fancier methods are under development for the future.

The Kelvin, fundamental unit of temperature, is a nice exception to this complexity.  It is defined in relation to the triple point of water; that temperature at which the liquid, solid, and vapor phases of isotopically controlled, gas and contaminant-free water are in equilibrium.  Measure this and the Kelvin is 1/273.16 of that.   The aptly named triple point cell requires appropriate water, a skilled glassblower, and some patience.   Thermometers can be calibrated against this standard within and across laboratories.

The Fluke Corporation, despite its name, has long been a respected supplier of a wide variety of test and measurement equipment and they sell such a triple point cell.  In the right hands, it can allow the temperature of 0.01C (the Centigrade and Kelvin are equivalent) to be measured with an uncertainty better than ± 0.0001 °C.  Here’s Fluke’s Matt Newman showing how it is done and not a laser to be seen.

Addendum 20 February 2019: The Kelvin has also been redefined as of November 2018.  It is now tied to Boltzmann’s constant, k.  NIST says that not much will change for the moment since the triple point cell is a known, reliable tool.

 

Guiding Waves to Guiding Light: The vacuum tubes among us

Before the laser came the maser and before that the radar that let civilization live long enough to create the other two.  We think that vacuum tubes have been completely overcome by their solid-state, fully integrated and integratable semiconductor rivals but they soldier on in niches where very high powers have to be sent out of antennas either to other antennas or to scatter back from targets.  Here’s a superb old video explaining the ‘klystron‘, a name fragrant with the aroma of old school pulp science fiction.   They’re still in use as are Traveling Wave Tube Amplifiers (TWTAs, pronounced ‘tweetas’) along with a few other devices that are coming up on nearly ninety years of life.

The Bell System is long gone but its manufacturing arm, the Western Electric Corporation, still has a website and offers products under its old banner.  Its ‘Historic Technical Library’ section is a goldmine of references.  Under ‘Western Electric Technology’ we can learn how to use our Picturephones and read the classic 1965 monograph, Principles of Electron Tubes.  The latter delves rigorously into the business of taking small radio signals and amplifying them to for communications, science, or surveillance.   Both klystrons and TWTAs get detailed treatment.  Fittingly, the final chapter is on gas lasers featuring the ever popular helium-neon variety  with only a brief mention of the carbon dioxide laser invented about the time the book would have gone to press.

It is easy to forget how the development of lasers and nonlinear optical devices came as logical outgrowths of the earlier work at much longer wavelengths – storing power in one medium and exchanging it to another all by playing games with resonances and the speed of light.   The Handbook allows the reader to rediscover these links, often for the first time.  It is not also surprising that places strong in the one such as Stanford; home of the brothers Varian, Edward Ginzton, and William Hansen of klystron fame, became so strong in the other with Schawlow, Hänsch, Siegman, Byer, and Harris. Of course, Bell Labs also falls into that category but it hardly bears repeating since it was so strong in so many areas.

Youtube Channel: 2020tesla

17 May 2021: Several Western Electric links updated

All Up In Ya Grille: The Automobile Driving Museum

From back in the day when cars had teeth: An assortment of dental excellence from El Segundo’s marvelous Automobile Driving Museum.  It looks like a showcase of lovingly restored and superbly maintained American cars and it is all that.  And the side of fries?  Machines are meant to be used and on Sundays, they take a rotating subset onto the roads and let the public ride along.

I went in not knowing that the museum was actually closed for a private party but no one said anything and I browsed the collection at leisure.  When I go back – and I will – I look forward to opening doors, sitting in the seats, and enjoying the insides of these artefacts of a bygone era.  That’s also allowed and encouraged.

See more about the ADM through the two videos following the gallery.

 

Vimeo Channel: Rupert Hitzig

Whiffleball: Bill Hammack on the IBM Selectric

Integrated electronics make us forget about them.  Tiny packages with millions of transistors encapsulate so many functions so effectively that we don’t or can’t know what all they do.  This is a boon to manufacturers since repairing anything is all but impossible.  In the not-too-distant past, these functions or a small subset of them, had to be implemented in metal.  Techmoan does a stellar job of rediscovering old technology.  Prof. Bill Hammack of UIUC is also a master of this.  Here he explains how the whiffletree mechanism enabled the IBM Selectric typewriter to work its magic.  Beware – it is easy to lose a day watching his other videos and searching on the nuggets he finds.

Youtube Channel: Engineerguy

 

Where are they now?: Carol Meier on Voyagers 1 and 2

Narrator Carol Meier has a meticulously researched, splendidly detailed, and wonderfully delivered update on the twin Voyager spacecraft and their epic journey of discovery from Pasadena to the outskirts of the solar system.  It isn’t clear if this is a commissioned piece or one she did on spec.  It is engrossing either way.

Youtube Channel: Carol Meier

Not just hot air: The GE MS9001E gas turbine

Without much further comment, here’s a very deep look into an industrial gas turbine engine. The CAD/CAM work is terrific and one wonders at the design and manufacturing effort put into just this one product.

[Edited 3 September 2018: Original video was taken down by the Youtube poster. Replaced with another link]
[Edited 6 January 2019: No longer available on the backup site, either.  Takedowns suspected]
[Edited 13 March 2019: Aaand it is back.  For now]

Youtube Channel: Ahmed Gaber