Feynman’s 'The Character of Physical Law' now with added commentary

  • Posted on: 19 April 2011
  • By: ashok
Tags: 

In July 2009, Microsoft Research released Project Tuva, based on the famed Messenger Lectures presented at Cornell University in 1964 by the late Richard Feynman, an American physicist and California Institute of Technology (Caltech) professor who shared the Nobel Prize in Physics in 1965 for his contributions to the development of quantum electrodynamics. Bill Gates, Microsoft chairman, made the lectures freely available to the public to encourage people to learn about science via a Silverlight-enhanced video player that presents the original, BBC-recorded videos of the seven physics lectures. The videos are searchable and include linked transcripts, notes, and interactive extras, originally including academic commentary on the first of the lectures.

Now commentary on all seven lectures has been added by Robert Jaffe, Jane and Otto Morningstar Professor of Physics at the Massachusetts Institute of Technology (MIT). Jaffe first met Feynman early in his academic career.

Feynman’s seven-part lecture series recorded at Cornell in 1964 now on YouTube

  • Posted on: 27 January 2011
  • By: ashok
Tags: 

I would encourage anyone interested in maths, physics or engineering to watch The Character of Physical Law, Feynman’s seven-part lecture series recorded at Cornell in 1964. The BBC recorded the seven lectures as part of the Messenger Lectures series.

The lectures covered the following topics:

  1. The law of gravitation, an example of physical law
  2. The relation of mathematics and physics
  3. The great conservation principles
  4. Symmetry in physical law
  5. The distinction of past and future
  6. Probability and uncertainty - the quantum mechanical view of nature
  7. Seeking new laws

Bamboo Domes

  • Posted on: 28 July 2010
  • By: ashok
Tags: 

Purpose

I would like to showcase a sustainable bamboo dome that was recently set up at Vigyan Ashram, Pabal, Pune, India. The three frequency icosahedron dome uses sustainable bamboo poles. By itself, and as displayed, the bamboo dome does not serve any habitation needs or any other needs. Yet is shows that thin bamboo sticks of fairly long spans have incredible strength in right geometries.

Design Thoughts for a New Solar Cooker

  • Posted on: 4 February 2010
  • By: ashok

What is wrong with the existing Solar cookers?

Summary

  1. They are made for the wrong audience.
  2. They are too expensive compared to the alternative devices already available with families to cook.
  3. They use the wrong technology.

Details

  1. They are made for the wrong audience.
    • For a family, they cannot cook food for the members who leave the home in the morning, say by 8 AM or 9 AM. In poor families where all the members go out for work, there is not much that a solar cooker can do.
    • They can cook lunch for about 180 to 200 days in a year for stay behind members.
    • If the Solar cookers are combined with hay-cookers, they can serve at least one hot dish for dinner. This requires that a cooking member should be home after 3 PM.
  2. They are too expensive compared to the alternative devices already available with families to cook.
    • A poor family that might benefit from not paying for fuel has its cooker as five bricks and a pot on the top. Often the pot is a tin that held 15 kgs of oil and is sold in the second hand market at a throw away price. It uses wood ( sticks, broken wooden crates, branches etc) as its fuel. The cooking arrangement of bricks and pot costs no more than ₹ 25 and wood is almost free. It works on all days and gives a hot meal by 8AM. At this price point it is not possible to design a solar cooker that can compete with the alternative. At least I am not making any effort to compete in this market.
    • A more middle class family where the mother stays at home ( and does not earn an income) and the family has a gas stove that cooks all the food whenever required can be characterized as having a device that cost between ₹ 600 to ₹ 900 and a monthly fuel bill of ₹ 150 to ₹ 200 a month. For it to cook with a solar cooker that works about half the time, the solar cooker needs to be designed to cost between ₹ 250 to ₹ 3,000. The cost of ₹ 250 represents an ideal value for money as it is just below the proportionate capital cost of the device that is already with the house wife. Paying more than ₹ 3,000 for a device means that the house hold is purchasing something costing 5 times the existing device to get a utility for one meal on 180 days out of 360. Roughly the cost of fuel saved balances the interest locked up in the device. For this market, we will try to make a solar cooker trying to keep the price as close to ₹ 250 as possible.
    • NB The present parabolic solar cookers in the Indian market cost anywhere from ₹ 10,000 to ₹ 8,500. Their high costs spring from the costly plastic (Mylar equivalent) reflecting surfaces that they use.

Papercrete: An Introduction

  • Posted on: 28 October 2009
  • By: ashok
Tags: 

What is papercrete?

Papercrete is a structural/ road building material recycling waste with properties that are a mix of wood and concrete.

Familiarity with paper, for most of us, obscures the fact that it is mostly wood fibre. Wood fibre and chips have significant strength, a fact that is daily attested by the wood board and particle board that we use and sit upon. To gain the strength, the wood fibres need to be bonded together by some adhesive. In case of papercrete that adhesive is cement. An alternative glue is lime but which not being considered in these phases as it is not a locally available material in the area of operation.

Look at concrete as an economical admixture of cement and stone aggregate. In concrete replace the stone aggregate with wood fibre (which are available from a wide variety of sources such as old newsprint, magazines, office waste paper, cardboard, corrugated sheets, straw, rice husk etc) and you have papercrete.

Papercrete is also known as fidobe, fibrecrete, padobe etc.It was first patented in USA in 1928 but for next 50 years did not move into mainstream usage. In 1980 two Americans Eric Patterson and Mike McCain independently invented mixers (tow mixers) that allowed papercrete to be made quite easily and started a revival of the material.

Pages