Akshat Jiwan Sharma

Quite an interesting discussion on materials sub-reddit today regarding the thickness of insulation and whether it relies upon material properties. Can we make insulating materials thinner? Exactly what physics is in play here?   Making insulation thick is inexpensive and does not add much weight either. Most of it is just air. And since air has very low thermal conductivity (.026 W/mK) it makes for an effective insulation. Aerogels work on the same principle: it's just a material frame for trapping lots of air ,of course with nano-scale pores suppressing conduction even further due to the knudsen effect.  But they are more difficult to manufacture , as compared to say thermal blankets which can be prepared by simple weaving.  Regarding physical limits — yes there is one. If we look at Fourier's law of thermal conductivity, it scales inversely with length. So a thinner insulation transfers more power than a thicker one of the same material.  And actually this pr...

I finally got an opportunity to meet Prof Rajesh Prasad in person this summer at IIT Delhi ,8 years after I first watched his lectures on materials science. It was by chance I stumbled across his video on composites when I was researching substrates for antennas. Fiber reinforced plastic came up repeatedly so I thought it wouldn't hurt to learn a bit more on this subject.  That was my first encounter with materials science. At that time I wasn't looking to go too deep, just learn enough to understand the systems that I was planning to work with. The idea was to build base stations with in house assembly and some quick engineering to attach components and protect them in a casing so that they could last a while. How hard could it be? Right? Only during the lockdown did I have enough time to take his full course.  My interest was in part because of my own desire to learn about materials — for engineering projects I had in mind but also because I wanted to break out o...

Advanced manufacturing, especially of functional materials, requires careful mapping of properties to the underlying microstructure. In technologies such as microfluidics,composites and electronics the features are either too small or too complex to be imaged using optical microscopes. Alternative imaging techniques are necessary so that the relation between material structure and materials properties can be understood.  X rays are an indispensable tool to look at micro and nano structure of materials both functional like electronics and structural like composites. Historically Xrays, since their discovery in 1895, have provided many breakthroughs in imaging that have enabled scientists to advance both material and medical fields. Bone imaging is the most well known application of X rays but the application of X ray diffraction also led to the confirmation of atomic structure in materials and the invention of x ray crystallography. This new technique was later used to i...

Durán is on to something when he talks about the big tech authoritarian movement. The argument that big tech is replacing the government at local,national and international levels is compelling and definitely backed by evidence. However I don't agree with the conclusion he draws.  He seems to suggest that there is a government elected by people and a class of private corporations that are usurping them. That's not what's happening. The history of America has always been private. From its foundation to the present day.  But what's happening right now is something more sinister where state entities work with private corporations to create systems of control where they can't legislate. Private corps and government institutions are not two separate things.  They are part of the same ugly,twisted nightmare of the deep state. Unelected officials at the FBI,CIA and the Pentagon control the technological and political agenda. During America's founding there...

For something as common as water filtration ,the modern technology that enables it, is built upon some serious materials engineering.  Polymer fibers,the active components of any filtration process, are spun using special coaxial extrusion techniques into what are known as hollow fiber membranes.  These membranes are then submerged inside the semi-treated water tank or wound around a plastic core for a more compact arrangement as water is drawn through these hollow sections the tiny pores on the surface trap impurities —suspended solids,bacteria,viruses,protein molecules depending upon the pore size.  Achieving this pore size tuning is in itself a quite complex process that relies on phase inversion where polymer solvent is replaced by non solvent on the solution, dissolved polymer coagulates but is diluted by a non solvent that evaporates leaving behind pores in the main structure.  Ceramic membranes offer a different class of materials that are more rob...

Power transmission plays a defining role in the energy security of a region but because the industry is more operationally intensive it rarely makes headlines, often working silently in the background to ensure critical services are kept running at all times.  Fluctuations in demand directly affects the rotation of generators leading to more or less watts on the line as required. Power systems engineering controls that.  Behind the scenes there is a complex system of tools from transformers and switchgears to HVDC converters and actual power lines to make this transmission happen.  These tools require highly standardized conductors and insulators to operate and their manufacturing is specialised.   At events in New Delhi I was fortunate enough to connect with engineers who specialise at component level engineering whether its automated systems that close the power line on towers ,the so called isolators, to manufacturing of electrical grade insulators whe...