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    What does it take to make one A4 size paper? 


    We start off by doing a small calculation from a reputed text book. The text book is Shreve’s Chemical Process Industries, which is a textbook adopted in the chemical engineering curriculum of many reputed colleges.

    An A4 size office paper of normal quality weighs 5 grams. It is easy for one to pro-rate the above table and estimate what it takes to make 5 grams of paper.

    Based on 1982 data, to make an A4 paper you would need:

    • 22.5 g  Chemicals
    • 665 ml  Water
    • 3.5 ml  Oil or 5 grams of coal
    • 20 cc Wood
    • 23.76 kJ Power

    Well, the story does not stop here. I know that the paper industry has adopted better manufacturing methods and today the specific consumption for making paper could be a little different. Today’s processes use significant amounts of recycle paper, use lesser water. Again, the amount of paper recycled and water conserved in different plants /countries is different, so it becomes difficult to establish an exact global average in a brief article.

    Nevertheless, a few parallels can be drawn.

    Every time you waste an A4 paper at office, conservatively, I can assume that, you also waste a large cup of water, a spoon full of coal (or oil), another spoonful of various chemicals, energy sufficient to keep a 40 W bulb glowing for 10 minutes and wood whose weight could be 2-4 times the weight of the paper, depending on the amount of recycle paper used.

    Every time you throw a piece of paper into a dust bin, imagine yourself wasting all the other resources as well. I’m sure you’ll find it a lot easier to save paper.

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    Educational objectives 


    There are said to be six major areas in the cognitive development process that includes: knowledge, comprehension, application, analysis, synthesis, and evaluation.

    1. Knowledge is remembering previously learned material, from specific facts to complete theories.
    2. Comprehension is the ability to grasp the meaning of material.
    3. Application is the ability to use learned material in and concrete situations. This may include the application of such things as rules, methods, and concepts.
    4. Analysis is defined as the ability to break down a problem into component parts so that its organization is understood.
    5. Synthesis is defined as the ability to put parts together to form a new whole view or aspect
    6. Evaluation is defined as the ability to judge the value of materials for a given purpose

    • Prakash 152404 on 20070823 Permalink

      Good Analysis. I comprehended the items, and could confirm my knowledge by recalling all six items. Would definitely be applicable in various situations and I should be able to synthesize this model into the bigger picture of things…. What say you about my evaluation?! :-)

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    Black Web, bright future 


    Anand Patil, my college mate, sent us all an email.

    When your screen is white, being it an empty word page, or the Google page, your computer consumes 74 watts, and when its black it consumes only 59 watts.

    Mark Ontkush wrote an article about the energy saving that would be achieved if Google had a black screen, taking in account the huge number of page views, according to his calculations, 750 mega watts / hour per year would be saved.

    In a response to this article Google created a black version of its search engine, called Blackle, with the exact same functions as the white version, but with a lower energy consumption check


    for more info …

    We can shut down a few power stations and pollute less without significant loss of fucntionality only if all our web pages are black.

    Please spread the word.

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    Online teaching – IITs 


    The IITs have taken up an initiative of starting online teaching and thus have started offering course materials online for every engineering stream. Many professors from all the IITs have provided course materials for each chapter and each subject.

    One has to register at the link provided below and can access the course material. Every Chapter has been described with diagrams and charts. Please spread this message to everyone, as many can benefit from this program taken up by the government and IIT.

    This is just a trial period going on and hence I request everyone to register at the link given.

    1] Go to http://nptel. iitm.ac.in
    2] Click on Courses
    3] Sign up as a NEW USER
    4] And one can access any course material.

    Please spread the word, so that this initiative benefits as many students as possible.

    • Hiren 150228 on 20060921 Permalink

      The link does not seem to be working but very interesting information. Thanks

    • GG 200012 on 20060922 Permalink

      Your link is not correct. It is pointing to http://nptel.iitm.ac.in//t_blank which does not exist. You have to remove the /t_blank part.

      Thanks for the news

    • kamal 151126 on 20060925 Permalink

      interesting information…

      just to put it here… IITs have earlier been producing video copies of their lectures and making it available to other institutes at nominal charges….

      but this is one unique step which will help everyone who has a net connection !! Institutional affiliations cease to matter!!

    • abhyudoy 144400 on 20060929 Permalink

      Respected sir,
      i have completed my graduation in electronics in JNT UNIVERSITY in 2005,and completed my advanced diploma in Digital Signal Processor (TMS320c6711),

      i would like to have a deep knowledge of DSP .

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