Buffon’s Discourse on Style – in English

Posted on 2011/06/04 by admin

It is among the greatest speeches ever made on how to write well for a scientific or technical audience. One of history’s great scientists will lay down a gauntlet: writing well can be as important, if not more important, than doing great science. Do you agree?

Today we listen to Georges-Louis Leclerc, the Comte de Buffon, better known simply as “Buffon”. Buffon was a famous French scientist from the late 1700’s. Although he made important discoveries in many scientific fields, primarily biology and mathematics, he won almost as much acclaim for his impeccable writing style. Frankly, that suited him just fine.

Buffon

Buffon: shall we remember him as a scientist, writer, or speaker?

When he was invited to the French Academy (of language, not the science one), he gave a famous speech called Discours sur le style (the “Discourse on Style“). Perhaps you can read the original in French, but the English-speaking world barely knows the tag-line: “the style is the man.” Nevertheless, it is one of the most famous talks ever on how to write well.

I have finally found a translation in English.  The following comes from The Story of Civilization Volume 10 – The Age of Voltaire, by Will and Ariel Durant.  We jump into the middle of their biography on Buffon. The Durants have some commentary before and after the speech, which I’ve left in place. Bolds and links are mine. Enjoy!

…[Buffon] was quite conscious of his literary flair. He delighted to read to his visitors melodious passages from his volumes; and when he was elected to the French Academy he took as his theme, on the day of his reception (August 25, 1753), not some marvel of science, but an analysis of style. That illustrious Discours, as Cuvier said, “gave at once the precept and the example,”… for it was itself a gem of style. From all but the French it is hidden in the mountain of his works, and little of it has come to us but its famous, pithy, cryptic judgment that “the style is the man.” Therefore let us spread it out here, and look at it leisurely. Its brilliance is dulled in translation, but even so, and though cruelly syncopated for our ignoble haste, it can adorn any page. Continue reading →

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How to Create an Electrical Area Classification Diagrams

Posted on 2011/05/20 by admin

Creating an Electrical Area Classification Diagram involves the following basic steps, done by electrical and mechanical/process/chemical engineers:

  1. Find all systems in the plant using flammable materials like hydrogen, natural gas, propane, butane, gas condensates, ammonia, flammable dusts, etc.
  2. Along the systems carrying flammables, identify on the plot plan the location of all flammable release sources such as: Open process points (like open tanks), Control valves, Pump seals, Rotating equipment, Seal pots, Drains, Metering points, Sampling points, Vents, PSVs, Rupture Disks. In general, closed metal piping or tubing without valves, fittings or flanges does not need to be considered as a potential source of release
  3. Get the correct electrical code, e.g. National Electrical Code (NEC) in U.S., or the Canadian Electrical Code (CEC), whatever applies. Classify the release sources identified in step #2 by the standard. For example, possible abnormal operation leak points along a Hydrogen system may be Class 1 Divison 2, Group B. (Meaning Flammable Gases, only occasionally present, gas is hydrogen). In many cases, the rating can be modified based on the quality of ventilation present.
  4. Create an area classification drawing, clouding the area around the hazards with the appropriate area classification. In some cases elevation drawings may also be required (especially multi-level structures). The area you must classify is often not specified in the electrical code, but depends on industry practice and site-specific tests of concentrations of flammable gases in simulated release scenarios. API 500 & 505 are good resources for determining the area to cloud around a potential hazard.
  5. If designing a new plant, ensure all equipment in the cloud is built to the standard specified by the cloud. If you are reviewing an existing plant, do a check to ensure that equipment inside the clouds are built for the classification. In some cases it may be possible to get an exception from the regulators for borderline cases

Good reference article: http://www.roe.com/pdfs/technical/practical%20guidelines%20for%20ctg%20power%20plants.pdf

You can hire consulting companies who are masters at steps 3 & 4, and do it easily, but steps 1, 2, and 5 still need the touch of people intimately knowledgeable about the system being drawn.

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Environmental emissions air dispersion calculation / air pollution from combustion

Posted on 2011/04/30 by admin

Suppose you want to estimate the combustion products from heaters, boilers, etc. Based on my experience, the environmental specialist doing the Gaussian distribution calculation needs the following needs the four pieces of information about the combustion equipment. Below, I list them, and suggest where you might find them:

  1. Amount of exhaust gas/complete combustion products: get by vendor quote, or by combustion equation (see below), or Combustion rules of thumb
  2. Amount of contaminates/incomplete combustion products: get by vendor quote or by the US EPA’s guideline AP 42
  3. Gas Discharge velocity: exhaust gas volume ÷ stack area (using stack diameter from vendor quote)
  4. Likely site location and weather conditions: from plot plan & site climate data. (Wind modeling / testing may be required in some cases)

You’ll notice I said “vendor quote” a lot – that’s the best source if you’ve got it. If not, time to look up similar results and ask around and do some digging.

Combustion Equation

Suppose you have a fuel source made up of some mixture of hydrocarbons and other molecules. You want to calculate the amount of exhaust gas your heater will exhaust by burning it. For simple fuels, you can do this manually.

Coal Furnace

But what's coming out the stack? (Photo credit: William Warby)

First, look up the chemical composition of the fuel you are combusting. Then, knowing your composition and the LHV of each chemical in your composition, determine the overall lower heating value per amount of fuel you combust. Then, look at your heater’s duty ÷ heater efficiency, and calculate the amount of fuel you will be burning in the heater. If you don’t know the heater efficiency yet, look into industry literature for an estimate.

Then, knowing the chemical composition of your fuel and how much fuel you must burn overall, figure out how many moles of each chemical species you will be burning.

For any mole of hydrocarbon of chemical formula CxHy, with e excess air (where 1 is 100% excess air and 0.03 is 3% excess air), using air which we will approximate as 79% N2 / 21% O2, and assuming 100% complete combustion as a first approximation, we have this reaction formula:

CxHy + (1+e)(x+y/4)O2 + (1+e)(79/21)(x+y/4)N2 –> xCO2 + (y/2)H2O + eO2 + (1+e)(79/21)(x+y/4)N2

So for example ethane is C2H6, so substitute x=2 and y = 6 above. You are providing the perfect amount of oxygen for the combustion, and e% extra on top to help ensure complete combustion. The N2 is from the air and just goes along for the ride. Continue reading →

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Considering whether to do an MBA?

Posted on 2011/04/16 by admin

The Economist has a MBA series, including what and where to study MBAs, how to write your MBA application, and how to write the perfect MBA essay. I think the latter two links are worth saving, even if you’re just considering an MBA.

Of course, if you prefer to take the self-study route, you could try this list of the 99 best business books ever.

Lastly, you might forget the whole thing and build your startup company on your own.

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More help finding salaries and control valve pressure drops

Posted on 2011/04/09 by admin

Hi everyone,

I updated the articles Salary Comparison & Prediction Tools and Assign Control Valve Pressure Drops with new resources. So you don’t have to re-read, here they are:

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Posted in Career Advice, Instrumentation & Controls, Pumps/Piping/Hydraulics | Leave a comment