to 100 ml of methanol the bobbin of gya 2 yarn was placed into the solution so formed for a period of 48 hours to regenerate glucan fiber from the glucan triacetate fiber the so treated bobbin was then rinsed with methanol and soaked for an additional 24 hours in neat methanol and allowed to air dry the resulting regenerated glucan fiber yarn is herein designated gy 1 referring to fig2 a tube furnace 21 having an entry port 22 and an exit port 22 u2032 was equipped with an air supply fan 23 that flowed air at rates stated in table 5 infra into the entry port 22 and through the furnace to the exit port 22 u2032 a skein of fiber 24 was fed end wise through the tube furnace the skein was disposed to pass over a pulley 25 at each end of the tube furnace each end of the skein was formed into a loop 26 through which a hook 27 was passed affixed to the hook was a weight 28 the weight employed is stated in the examples infra the heated section of the tube inside the tube furnace was a 2 inch schedule 5 tube with an inner diameter of 57 mm and a length of 54 inches each specimen was subject to a temperature of 180 u00b0 c in air for 10 minutes the temperature was then increased in a series of steps as described in the thermal profile provided in the examples infra it took less than 1 minute to make the temperature changes between adjacent steps in the thermal profile referring to fig3 nitrogen was provided to the tube furnace 21.