TA Instruments AR 2000 User Manual

AR 2000 Operator's Manual
118
Analyzing the Results
Calculation of the Interfacial Contribution to the Torque
The interfacial contribution to the torque, M
interfacial
(Ω) at a particular angular velocity is calculated by subtract-
ing the contributions of the two bulk fluids, A and B from the total torque for the system at that angular velocity,
i.e.:
M
total
(Ω) = M
interfacial
(Ω) + M
A
(Ω) + M
B
(Ω)
M
A
and MB, are obtained from the calibration routine described above. But M
A
(Ω) is half the torque obtained at
Ω for Fluid A from the calibration routine, and M
B
is half that obtained for Fluid B, since for the calibration
routines the cell is filled with the relevant fluid, whereas for the interfacial measurement it is half filled with
Fluid A and half with Fluid B, i.e.:
M
A
(Ω) = M
Acalibration
(Ω) / 2 and M
B
(Ω) = M
Bcalibration
(Ω) / 2
Three data points are therefore needed for each angular velocity used:
• the calibration data point for Fluid A
• the calibration data point for Fluid B
• the data point for the total system
Then:
M
interfacial
(Ω) = M
total
(Ω) - [(M
Acalibration
(Ω) / 2) + (M
Bcalibration
(Ω) / 2)]
M
interfacial
(Ω) = M
total
(Ω) - [M
Acalibration
(Ω) + (M
Bcalibration
(Ω)] / 2

TA Instruments AR 2000 Specifications

General

Brand	TA Instruments
Model	AR 2000
Category	Measuring Instruments
Language	English