Ice602: double sample
  top: 3 x P-drop f.g. ice I + 3% by vol 1-micron Al2O3
  bottom: pure 3 x P-drop f.g. ice I
  cold press 12 hrs at 120 MPa, 210 K
   
Conditions: all steps P = 50 MPa  
T = 210 K, s = 4.8 MPa step (1); teminated by unintentional 10 K warming
T = 220 K, s = 2.70 MPa step (2)
T = 220 K, s = 2.0 MPa steps (3a)-(3f)
   

 

Legend: Upper graph of each pair is motor speed V (proportional to edot); lower graph is load (in volts). Translate motor V to edot thus: for 100:1 gearing, V0.05 ≈ 3e-8/s; for 10:1 gearing, V0.05≈5e-7/s. Load to stress translation for ice602 is 0.252 MPa/mV, with a ~5 mV zero offset. Horizontal scale is time. 5000≈14 hrs.

  

 

 
e=0.126

1445 hrs 6/1/10, end of run. Knocked the force gage zero near the end there (whence step 3f), quick adjustment kept true stress unchanged.

SO: Mildly spectacular final result in the table just above. Depending on n, adding 3% dust to f.g. ice increases its viscosity by upwards of a factor of 2.

Additionally, note that the viscosity contrast in step (3) was clearly higher than over steps (1)+(2). Difference is the differential stress being lower in step (3). This tends to support our earlier observation that n is higher in dusty f.g. ice. Pretty nifty!
e=0.123 0619 hrs 6/1. Start of step (3e)
e=0.118 1817 hrs 5/31. Step (3d)
e=0.111 1755 hrs 5/30. Step (3c)
e=0.107 1111 hrs 5/30. End of step (3b)
e=0.101 2226 hrs 5/29.
e=0.096 1122 hrs 5/29
e=0.090 2334 hrs 5/28. Start of step (3b).
e=0.083 1127 hrs 5/28. End of step (3a).
e=0.075 2045 hrs 5/27. Start of step (3a). Stress here chosen to give ~50% of the combined edot of the previous step. If n values for the two pieces are different, the differences between them should stand out even more than after step (2).
e=0.069 0841 hrs. End of step (2). Sample removed, measured, and photographed. Qualitative look says the pure f.g. sample is deforming faster at a lower stress [lower because edot is faster: area grows as edot. Get it?]. More detailed results soon.
e=0.051 2045 hrs 5/26, start of step (2). T is now 220 K.
e=0.035

0534 hrs 5/26/10, all of step (1). LN tank malfunctioned beginning shortly before midnight; T warmed to 215 K at the time the step was halted here, then to near 220 K by the time I got to work.

Decide to continue at 220 K. Value of edot here before warming event is only slightly higher that of 100% f.g. ice + 3% dust anyway.