[math-fun] apology, Ramanujan, and flame flame
This is mainly to apologize to my eavesdroppers for the accidental, Thanksgiving resend of my long jr. high textbook flame. My "student" (who, regrettably, has chosen TV over scholarship) has moved from preppie Los Altos to the (prominently posted) Nuclear Free Zone of Santa Cruz. But instead of courses in basketry and banana slug husbandry, the school features a good curriculum, good teachers, an amazingly helpful administration, and way better textbooks. The algebra I book, by three mathematicians instead of 200 educationists, has well-designed problems featuring sneak previews of such advanced topics as continued fractions and convergent series. The book is also sprinkled with the obligatory biographical sketches (and color portraits) of non-White mathematicians, including one of Srinivasa Ramanujan (as if he needed affirmative action!). The text is fairly accurate, and clearly indicates he died in his early 30s, but the portrait is of a middle-aged man in a Nehru cap and tiny-lensed granny glasses! I've shown the picture to many Indian friends, but nobody can place him. Was there more than one Ramanujan? Is his image copyrighted? Wherefore this screwup? Another oddity: despite the fine efforts of the school, it lags Los Altos by 6 months to a year. Student demographics? Perhaps a higher %age of disadvantaged Hispanics and stoned-out beach bums whose parents sell candles and incense on the Boardwalk? "No chemicals!" Anyway, the kid's new house features (of course) a woodstove ("Split wood, not atoms"), called, I think, Swedish circle-fire. It's a nifty, nonagonal glass prism which, unlike a fireplace, can burn completely unseasoned wood. A 13" slice of freshly cut red gum (ironwood) recently burned for 14 hours! The stove preheats its fuel by recirculating combustion products and perhaps IR due to a greenhouse effect from the glass. With seasoned wood, I have twice observed an intriguing effect: increased temperature, and maybe even combustion rate, with INcreased damping! Apparently, if you do it just right, you can reduce the power lost up the chimney faster than you reduce the combustion power, resulting in an at least temporary temperature rise. But this increases the rate of fuel heating, resulting in positive feedback. So it goes from a softly roaring fireplace type fire to this weird, quiet flame that soon engulfs every combustible surface. The first time this happened, the stove got so hot that its funnel paint smoked up the house, and we had to OPEN the dampers to cool it! But how could the combustion *rate* increase with decreased O2? Guess 1: higher %age O2 utilization. Guess 2: Hotter stove and flue temps boost convection to the point of overcoming the damping. Guess 3: It doesnt really increase. It only looks (and feels!) that way due to the enormity of the heat not escaping up the chimney. --rwg
participants (1)
-
R. William Gosper