DuPont’s nylon – hard to imagine the world without it

Our subject for today is nylon, the wonder-plastic developed and first produced in the 1930’s by DuPont. Today, 16 February, is the day in 1937 that Dr Wallace Carothers, inventor and research chemist for DuPont, received the first patent for the new synthetic polymer fiber that came to be known as nylon.

The new plastic fiber proved tremendously useful, and to this day is used in a wide range of applications, from industrial (screws and nuts, gears, bearings), to sports (fabrics, fishing line, racket strings), to entertainment (guitar strings), to domestic products (brush bristles, hosiery, carpeting) and many more.

Nylon's strength, flexibility and durability make it a popular material for 3D prototype printing.(© All Rights Reserved)
Nylon’s strength, flexibility and durability make it a popular material for 3D prototype printing.
(© All Rights Reserved)

Nylon’s usefulness is the result of a combination of many advantageous properties – it is strong, flexible and durable, with excellent resistance to heat, chemicals, abrasion and wear. It is also resistant to fungi, mould and mildew.

It’s flexibility and strength make nylon ideal for 3D printing applications. Complex gears, bearings etc can be printed using a 3D plastic printer – this is particularly useful for the production of strong, durable engineering prototypes.

Of course few things in life are perfect, and along with all it’s positive attributes nylon does have some drawbacks. Producing nylon is an energy intensive activity, and it is rather difficult to recycle. Burning it produces hazardous smoke and toxic fumes often containing hydrogen cyanide, and if it’s dumped in the garbage it decays very slowly. Some nylon is recycled, often creating nylon pellets for industrial use, but this only accounts for a very small percentage of nylon produced annually.

Despite the recycling downside, nylon has become a ubiquitous part of daily life – so much so that imagining a world without it is nigh impossible.

Ray Dolby, shaping sound as we know it

Today we celebrate the birthday of Ray Dolby (18 Jan 1933), the American engineer and physicist who invented the Dolby Noise Reduction System.

Dolby Digital - keeping the Dolby name relevant in the digital era.(© All Rights Reserved)
Dolby Digital – keeping the Dolby name relevant in the digital era.
(© All Rights Reserved)

Dolby started his career in sound engineering while still at school, when he worked part-time at the Ampex Corporation. During his college years he became part of a team of engineers who invented the first practical video tape recorder in 1956. He subsequently started his own company, Dolby Laboratories, where he developed his noise reduction technologies, starting with Dolby A (1966), a broadband audio compression and expansion technique aimed at recording studios, with which audible tape hiss in professional tape recording can be significantly reduced without any discernible side-effects.

While Dolby A had real impact in the recording industry, perhaps the better known technology is Dolby B (1968), a sliding band noise reduction system aimed at the consumer market, which helped achieve high fidelity on cassette tapes.

All the Dolby variants work through a technique dubbed ‘companding’, which involves compressing the dynamic range of the sound during recording (‘dynamic pre-emphasis’), and expanding it during playback (‘dynamic de-emphasis’). This basically comes down to increasing the volume of low-level high-frequency sounds during recording and correspondingly reducing them during playback, thus reducing audible levels of tape hiss.

Various further iterations of Dolby’s audio noise reduction have subsequently been introduced, including Dolby C (1980), Dolby SR (1986) and Dolby S (1989).

Beyond noise reduction, Dolby Laboratories have also done ground-breaking work in the field of digital audio encoding and compression. Dolby Digital – first developed for movie theatres and later implemented in DVDs – is a digital audio compression format that was instrumental in the popularisation of surround sound. It has also been adopted as output format in most video game consoles, and several personal computers. Subsequent iterations of this technology include Dolby Digital EX, Dolby Digital Plus and Dolby Digital Live.

To say that Ray Dolby and his noise reduction and audio compression technologies have influenced the way we experience recorded sound, is an understatement. He has fundamentally shaped the way sound is recorded and reproduced, and his technologies have become so pervasive in sound reproduction that it is almost impossible to quantify its impact.

Transistors – the electronic engineer’s dream

On this day back in 1947, Walter Brattain and John Bardeen had a big day – they did the first live demonstration of a transistor, in a presentation to their superiors at Bell Laboratories.

In the demo, a microphone and headphones were connected to a transistor, and when they spoke over the device, there was ‘no noticeable change in quality’ (according to Brattain’s notes). They finished building their demonstration device just a few short days earlier, on 16 December 1947, so I am sure the excitement must have been quite high on the day of the demo to the bosses.

The name ‘transistor’, by the way, was chosen because of the trans-resistance properties of the component.

Compact, rugged little transistors, replacing the bulky and fragile vacuum tubes of old.(© All Rights Reserved)
Compact, rugged little transistors, replacing the bulky and fragile vacuum tubes of old.
(© All Rights Reserved)

The transistor was basically a much smaller and more usable replacement for the bulky vacuum tubes used before, and as such opened up many new possibilities in electronic component development. This lead to it being referred to as ‘the electronic engineer’s dream’.

At least their efforts didn’t go unnoticed – for their invention, Brattain and Bardeen shared the 1956 Nobel Price for Physics.