ASTM D3829-02(2007)
(Test Method)Standard Test Method for Predicting the Borderline Pumping Temperature of Engine Oil
Standard Test Method for Predicting the Borderline Pumping Temperature of Engine Oil
SIGNIFICANCE AND USE
Borderline pumping temperature is a measure of the lowest temperature at which an engine oil can be continuously and adequately supplied to the oil pump inlet of an automotive engine.
SCOPE
1.1 This test method covers the prediction of the borderline pumping temperature (BPT) of engine oils through the use of a 16-h cooling cycle over the temperature range from 0 to −40°C.
1.2 Applicability to petroleum products other than engine oils has not been determined.
1.3 This test method uses the millipascal (mPa·s), as the unit of viscosity. For information, the equivalent centipoise unit is shown in parentheses.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D3829 − 02(Reapproved 2007)
Standard Test Method for
Predicting the Borderline Pumping Temperature of Engine
Oil
This standard is issued under the fixed designation D3829; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4πR
s
G 5 (2)
2 2
r
t R 2 R
~ !
s r
1.1 This test method covers the prediction of the borderline
pumping temperature (BPT) of engine oils through the use of
where:
a 16-h cooling cycle over the temperature range from 0 to
G = shear rate at the surface of the rotor in reciprocal
r
−1
−40°C.
seconds, s ,
Ω = angular velocity, rad/s,
1.2 Applicability to petroleum products other than engine
R = stator radius, mm,
oils has not been determined. s
R = rotor radius, mm, and
r
1.3 Thistestmethodusesthemillipascal(mPa·s),astheunit
t = time in seconds for one revolution of the rotor.
of viscosity. For information, the equivalent centipoise unit is
For the specific apparatus being described in 5.1.1,
shown in parentheses.
1.4 This standard does not purport to address all of the
G 5 (3)
r
t
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 2.1.5 shear stress—the motivating force per unit area for
priate safety and health practices and determine the applica- fluid flow. Area is the area under shear. For the rotary
bility of regulatory limitations prior to use. viscometer being described, the rotor surface is the area under
shear.
2. Terminology
T 5 9.81M R 1R 310 (4)
~ !
r o t
2.1 Definitions:
T
r
S 5 310 (5)
2.1.1 apparent viscosity—the determined viscosity obtained
r 2
2π R h
r
by use of this test method.
where:
2.1.2 Newtonian oil or fluid—an oil or fluid that at a given
T = torque applied to rotor, N·m,
r
temperature exhibits a constant viscosity at all shear rates or
M = applied mass, g,
shear stresses.
R = radius of the shaft, mm,
o
2.1.3 non-Newtonian oil or fluid—an oil or fluid that at a
R = radius of the thread, mm,
t
given temperature exhibits a viscosity that varies with chang-
S = shear stress at the rotor surface, Pa, and
r
ing shear stress or shear rate.
h = height of the rotor, mm.
2.1.4 shear rate—the velocity gradient in fluid flow. For a
For the dimensions given in 5.1.1,
Newtonian fluid in a concentric cylinder rotary viscometer in
T 5 31.7M 310 (6)
r
which the shear stress is measured at the inner cylinder surface
S 5 3.5M (7)
r
(such as the apparatus being described), and ignoring any end
effects, the shear rate is given as follows:
2.1.6 viscosity—the ratio between the applied shear stress
2 and rate of shear. It is sometimes called the coefficient of
2ΩR
s
G 5 (1)
r 2 2 dynamic viscosity. This value is thus a measure of the
~R 2 R !
s r
resistance to flow of the liquid. The SI unit of viscosity is the
pascal second (Pa·s). The centipoise (cP) is one millipascal
second (mPa·s) and is often used.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
2.2 Definitions of Terms Specific to This Standard:
D02.07 on Flow Properties.
2.2.1 borderline pumping temperature—the maximum tem-
Current edition approved Nov. 1, 2007. Published January 2008. Originally
perature at which the critical yield stress or critical viscosity
approved in 1979. Last previous edition approved in 2002 as D3829–02. DOI:
10.1520/D3829-02R07. occurs, whichever is the higher temperature.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3829 − 02 (2007)
2.2.2 calibration oils—those oils for establishing the instru-
Diameter of rotor 17.0 mm
Length of rotor 20.0 mm
ment’sreferenceframeworkofapparentviscosityversusspeed
Inside of diameter of cup 19.0 mm
from which the apparent viscosities of test oils are determined.
Radius of shaft 3.18 mm
Calibration oils, which are essentially Newtonian fluids, are
Radius of string 0.1 mm
available commercially, and have an approximate viscosity of 2
5.2 Thermometers, for measuring temperature of the block.
30 000 mPa·s (30 000 cP) at −20°C.
Two are required, one graduated from at least +70 to 90°C in
2.2.3 critical viscosity—the maximum viscosity at a defined
1°C subdivisions, the other with a scale from at least −36 to
shear rate to allow adequate flow of oil to the oil pump in an
+5°C in 0.2°C subdivisions.
automotive engine. A higher viscosity can cause failure to
5.3 A means of lowering the temperature to the predeter-
maintain adequate oil pressure through the limiting of flow
mined test temperature at a controlled, nonlinear rate.
through the oil screen or oil inlet tubes.
5.4 Circulating System, for supplying suitable liquid cool-
2.2.4 critical yield stress—the maximum yield stress that
ant to the block as needed. Methanol is a suitable coolant. One
allows oil to flow to the inlet oil screen in an automotive
should observe toxicity and flammability precautions that
engine. With a higher yield stress, air may be drawn into the
apply to the use of methanol. The circulating system must be
pump and cause failure to maintain adequate oil pressure
capableofmaintainingtesttemperatureovera16-htestperiod.
through air-binding of the pump.
Ifmethanolisleakingfromthesystem,discontinuethetestand
2.2.5 test oil—any oil for which the apparent viscosity and
repair the leak before continuing.
yield stress are to be determined by use of the test method
5.5 Chart Recorder, to verify that the correct cooling curve
under description.
is being followed, it is recommended that a chart recorder be
2.2.6 yield stress—the shear stress required to initiate flow.
used to monitor the block temperature.
ForallNewtonianfluidsandsomenon-Newtonianfluids,yield
stress is zero. Some engine oils have a yield stress that is a
6. Reagents and Materials
function of their low-temperature cooling rate, soak time, and
temperature.
6.1 Low Cloud-Point, Newtonian Oil, of approximately 30
Pa·s (30 000 cP) viscosity at −20°C for calibration of the
3. Summary of Test Method
viscometric cells.
3.1 An engine oil sample is cooled from 80°C to the desired
6.2 Methanol, commercial or technical grade of dry metha-
test temperature at a nonlinear programmed cooling rate over a
nol is suitable for the cooling bath.
10-h period and held at the test temperature for the remainder
6.3 Oil Solvent, commercial heptanes or similar solvent is
of a 16-h period. After completion of the soak period, two
suitable.
standard torques of increasing severity are applied to the rotor
shaft and the speed of rotation in each case is measured. From
6.4 Acetone, technical grade of acetone is suitable provided
the results at three or more temperatures, the borderline
it does not leave a residue upon evaporation.
pumping temperature is determined.
7. Sampling
3.2 Alternatively, for some specification or classification
purposes it may be sufficient to determine that the BPT is less
7.1 A representative sample of test oil free from suspended
than a certain specified temperature.
solid material and water is necessary to obtain valid results. If
the sample in its container is received below the dew-point
4. Significance and Use
temperature of the room, allow to warm to room temperature
4.1 Borderline pumping temperature is a measure of the
before opening.
lowest temperature at which an engine oil can be continuously
and adequately supplied to the oil pump inlet of an automotive
8. Calibration and Standardization
engine.
8.1 Calibration is required for the temperature dial on the
panel.
5. Apparatus
8.1.1 Place calibrated thermometer in position (see assem-
5.1 Mini-Rotary Viscometer, consisting of one or more vis-
bly instructions) and turn the RESET dial fully counterclock-
cometric cells including a calibrated rotor-stator assembly,
wise.
which are contained in a temperature-controlled aluminum
8.1.2 Set the dial at 100 and allow to cool to control
block.
temperature. Allow approximately 30 min for temperature
5.1.1 The viscometric cell has the following nominal di-
equilibrium to be established.
mensions:
8.1.3 Record the temperature.
8.1.4 Repeat 8.1.3 and 8.1.4 for dial settings of 200, 300,
The sole source of supply of the apparatus known to the committee at this time
500, 700, and 900 or until −37°C has been reached.
is Cannon Instrument Co., P.O. Box 16, State College, PA16801. If you are aware
8.1.5 On one- or two-cycle semilog graph paper, plot log
of alternative suppliers, please provide this information to ASTM International
(reading) versus temperature (°C) to establish calibration
Headquarters.Your comments will receive careful consideration at a meeting of the
responsible technical committee, which you may attend. curve. See Fig. 1.
D3829 − 02 (2007)
FIG. 1 Typical Dial Calibration
8.2 The calibration of each viscometric cell (viscometer 8.4 Check the rate of cooling periodically to ensure a
constants) can be determined with the viscosity standard and standard cool down rate. The reset knob should rotate one
the following procedure at −20 6 0.2°C. complete revolution each hour for 10 h, but must not turn
8.2.1 Use steps 9.1.1-9.1.5. during the final 6-h soak period. The approximate temperature
8.2.2 Set the temperature-control, ten-turn dial to corre- of the thermometer at hourly intervals is shown in Table 1 for
spond to −20°C and turn switch to cool. cooling to a final temperature of −20°C, and should be attained
8.2.3 Allow to soak at −20 6 0.2°C for at least 1 h, making within the limits shown in the table. A chart recorder may be
small temperature adjustments, if necessary, to maintain the used to monitor the temperature cool down rate.
test temperature.
9. Procedure
8.2.4 At the end of the soak period record the temperature
reading (test temperature), and remove the cover of the
9.1 Test Sample and Viscometric Cell Preparation:
viscometer cell.
9.1.1 With the viscometric cells clean and at ambient
8.2.5 Proceed to steps 9.2.1-9.2.3.
temperature, remove the nine rotors.
8.2.6 Place a 150-g mass on the string in accordance with
9.1.2 Place a 10 6 1 mL oil sample in each cup.
instructions in 9.3.1.
9.1.3 Install the rotors in the proper stator
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
An American National Standard
Designation:D3829–93 (Reapproved 1998) Designation: D 3829 – 02 (Reapproved 2007)
Standard Test Method for
Predicting the Borderline Pumping Temperature of Engine
Oil
This standard is issued under the fixed designation D3829; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 Thistestmethodcoversthepredictionoftheborderlinepumpingtemperature(BPT)ofengineoilsthroughtheuseofa16-h
cooling cycle over the temperature range from 0 to −40°C.
1.2 Applicability to petroleum products other than engine oils has not been determined.
1.3This1.3 Thistestmethodusesthemillipascal(mPa·s),astheunitofviscosity.Forinformation,theequivalentcentipoiseunit
is shown in parentheses.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Terminology
2.1 Definitions:
2.1.1 viscosity—the ratio between the applied shear stress and rate of shear. It is sometimes called the coefficient of dynamic
viscosity. This value is thus a measure of the resistance to flow of the liquid. The SI unit of viscosity is the pascal second (Pa·s).
The centipoise (cP) is one millipascal second (mPa·s) and is often used. apparent viscosity—the determined viscosity obtained by
use of this test method.
2.1.2 Newtonian oil or fluid—an oil or fluid that at a given temperature exhibits a constant viscosity at all shear rates or shear
stresses.
2.1.3 non-Newtonian oil or fluid—an oil or fluid that at a given temperature exhibits a viscosity that varies with changing shear
stress or shear rate.
2.1.4 apparent viscosity—the determined viscosity obtained by use of this test method.
2.1.5shear rate—the velocity gradient in fluid flow. For a Newtonian fluid in a concentric cylinder rotary viscometer in which
the shear stress is measured at the inner cylinder surface (such as the apparatus being described), and ignoring any end effects, the
shear rate is given as follows:
2VR
s
G 5 (1)
r
~R – R !
s2 r
2VR
s
G 5 (1)
r 2 2
~R – R !
s r
4pR
s
G 5 (2)
r 2 2
t~R – R !
s r
where:
−1
G = shear rate at the surface of the rotor in reciprocal seconds, s ,
r
V = angular velocity, rad/s,
R = stator radius, mm,
s
R = rotor radius, mm, and
r
t = time in seconds for one revolution of the rotor.
For the specific apparatus being described in 5.1.1,
This test method is under the jurisdiction ofASTM Committee D-2D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.07
on Flow Properties.
CurrenteditionapprovedSept.15,1993.Nov.1,2007.PublishedNovember1993.January2008.OriginallypublishedasD3829–79.approvedin1979.Lastpreviousedition
D3829–87.approved in 2002 as D3829–02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 3829 – 02 (2007)
G 5 (3)
r
t
2.1.62.1.5 shear stress—the motivating force per unit area for fluid flow.Area is the area under shear. For the rotary viscometer
being described, the rotor surface is the area under shear.
T 59.81M~R 1 R ! 310 (4)
r o t
T
r
S 5 310 (5)
r 2
2p R h
r
where:
T = torque applied to rotor, N·m,
r
M = applied mass, g,
R = radius of the shaft, mm,
o
R = radius of the thread, mm,
t
S = shear stress at the rotor surface, Pa, and
r
h = height of the rotor, mm.
For the dimensions given in 5.1.1,
T 531.7M 310 (6)
r
S 53.5M (7)
r
2.1.6 viscosity—the ratio between the applied shear stress and rate of shear. It is sometimes called the coefficient of dynamic
viscosity. This value is thus a measure of the resistance to flow of the liquid. The SI unit of viscosity is the pascal second (Pa·s).
The centipoise (cP) is one millipascal second (mPa·s) and is often used.
2.2 Definitions of Terms Specific to This Standard:
2.2.1 borderline pumping temperature—the maximum temperature at which the critical yield stress or critical viscosity occurs,
whichever is the higher temperature.
2.2.2 calibration oils—thoseoilsforestablishingtheinstrument’sreferenceframeworkofapparentviscosityversusspeedfrom
which the apparent viscosities of test oils are determined. Calibration oils, which are essentially Newtonian fluids, are available
commercially, and have an approximate viscosity of 30000 mPa·s (30000 cP) at−20°C.
2.2.2test oil—any oil for which the apparent viscosity and yield stress are to be determined by use of the test method under
description.
2.2.3 yield stress—the shear stress required to initiate flow. For all Newtonian fluids and some non-Newtonian fluids, yield
stress is zero. Some engine oils have a yield stress that is a function of their low-temperature cooling rate, soak time, and
temperature. critical viscosity—the maximum viscosity at a defined shear rate to allow adequate flow of oil to the oil pump in an
automotive engine.Ahigher viscosity can cause failure to maintain adequate oil pressure through the limiting of flow through the
oil screen or oil inlet tubes.
2.2.4 critical yield stress—themaximumyieldstressthatallowsoiltoflowtotheinletoilscreeninanautomotiveengine.With
a higher yield stress, air may be drawn into the pump and cause failure to maintain adequate oil pressure through air-binding of
the pump.
2.2.5 critical viscosity—the maximum viscosity at a defined shear rate to allow adequate flow of oil to the oil pump in an
automotive engine.Ahigher viscosity can cause failure to maintain adequate oil pressure through the limiting of flow through the
oil screen or oil inlet tubes. test oil—any oil for which the apparent viscosity and yield stress are to be determined by use of the
test method under description.
2.2.6 borderline pumping temperature—the maximum temperature at which the critical yield stress or critical viscosity occurs,
whichever is the higher temperature. yield stress—the shear stress required to initiate flow. For all Newtonian fluids and some
non-Newtonian fluids, yield stress is zero. Some engine oils have a yield stress that is a function of their low-temperature cooling
rate, soak time, and temperature.
3. Summary of Test Method
3.1 An engine oil sample is cooled from 80°C to the desired test temperature at a nonlinear programmed cooling rate over a
10-h period and held at the test temperature for the remainder of a 16-h period.After completion of the soak period, two standard
torques of increasing severity are applied to the rotor shaft and the speed of rotation in each case is measured. From the results
at three or more temperatures, the borderline pumping temperature is determined.
3.2Alternatively,3.2 Alternatively, for some specification or classification purposes it may be sufficient to determine that the
BPT is less than a certain specified temperature.
4. Significance and Use
4.1 Borderline pumping temperature is a measure of the lowest temperature at which an engine oil can be continuously and
adequately supplied to the oil pump inlet of an automotive engine.
D 3829 – 02 (2007)
5. Apparatus
5.1 Mini-Rotary Viscometer, consistingofoneormoreviscometriccellsincludingacalibratedrotor-statorassembly,whichare
contained in a temperature-controlled aluminum block.
5.1.1 The viscometric cell has the following nominal dimensions:
Diameter of rotor 17.0 mm
Length of rotor 20.0 mm
Inside of diameter of cup 19.0 mm
Radius of shaft 3.18 mm
Radius of string 0.05 mm
Radius of string 0.1 mm
5.2 Thermometers, formeasuringtemperatureoftheblock.Twoarerequired,onegraduatedfromatleast+70to90°Cin1°C
subdivisions, the other with a scale from at least−36 to +5°C in 0.2°C subdivisions.
5.3 A means of lowering the temperature to the predetermined test temperature at a controlled, nonlinear rate.
5.4 Circulating System, for supplying suitable liquid coolant to the block as needed. Methanol is a suitable coolant. One
should observe toxicity and flammability precautions that apply to the use of methanol. The circulating system must be capable
of maintaining test temperature over a 16-h test period. If methanol is leaking from the system, discontinue the test and repair the
leak before continuing.
5.5 Chart Recorder, to verify that the correct cooling curve is being followed, it is recommended that a chart recorder be used
to monitor the block temperature.
6. Reagents and Materials
6.1 Low Cloud-Point, Newtonian Oil, of approximately 30 Pa·s (30 000 cP) viscosity at−20°C for calibration of the
viscometric cells.
6.2 Methanol, commercial or technical grade of dry methanol is suitable for the cooling bath.
6.3 Oil Solvent, commercial Heptanesheptanes or similar solvent is suitable.
6.4 Acetone, technical grade of acetone is suitable provided it does not leave a residue upon evaporation.
7. Sampling
7.1 Arepresentative sample of test oil free from suspended solid material and water is necessary to obtain valid results. If the
sample in its container is received below the dew-point temperature of the room, allow to warm to room temperature before
opening.
8. Calibration and Standardization
8.1 Calibration is required for the temperature dial on the panel.
8.1.1 Place calibrated thermometer in position (see assembly instructions) and turn the RESET dial fully counterclockwise.
8.1.2 Set the dial at 100 and allow to cool to control temperature.Allow approximately 30 min for temperature equilibrium to
be established.
8.1.3 Record the temperature.
8.1.4 Repeat 8.1.3 and 8.1.4 for dial settings of 200, 300, 500, 700, and 900 or until−37°C has been reached.
8.1.5 On one- or two-cycle semilog graph paper, plot log (reading) versus temperature (°C) to establish calibration curve. See
Fig. 1.
8.2 The calibration of each viscometric cell (viscometer constants) can be determined with the viscosity standard and the
following procedure at−20 6 0.2°C.
8.2.1 Use steps 9.1.1-9.1.5.
8.2.2 Set the temperature-control, ten-turn dial to correspond to−20°C and turn switch to cool.
8.2.3 Allow to soak at −20 6 0.2°C for at least 1 h, making small temperature adjustments, if necessary, to maintain the test
temperature.
8.2.4 At the end of the soak period record the temperature reading (test temperature), and remove the cover of the viscometer
cell.
8.2.5 Proceed to steps 9.2.1-9.2.3.
8.2.6 Place a 150-g mass on the string in accordance with instructions in 9.3.1.
8.2.7 Repeat 8.2.5 and 8.2.6 for each of the remaining cells, taking the cells in order from left to right.
8.2.8 Calculate the viscometer constant for each cell (rotor/stator combination) with the following equation:
h
o
C 5 (8)
Mt
Available from Cannon Instrument Co., P.O. Box 16, State College, PA 16801.
The sole source of supply of the apparatus known to the committee at this time is Cannon Instrument Co., P.O. Box 16, State College, PA 16801. If you are aware of
alternative suppliers, please provide this information toASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend.
D 3829 – 02 (2007)
FIG. 1 Typical Dial Calibration
Mt
where:
h = viscosity of the standard oil, mPa·s (cP) at−20°C,
o
C = cell constant, Pa (N/m g),
M = applied mass, g, and
t = time in seconds for one revolution.
8.3 It is essential that the ice point of the calibrated thermometer be measured initially and periodically thereafter, and that the
corrections be adjusted to conform with any change in the ice point.
8.4 Check the rate of cooling periodically to ensure a standard cool down rate. The reset knob should rotate one complete
revolution each hour for 10 h, but must not turn during the final 6-h soak period.The approximate temperature of the thermometer
at hourly intervals is shown inTable 1 for cooling to a final temperature of −20°C, and should be attained within the limits shown
in the table. A chart recorder may be used to monitor the temperature cool-downcool down rate.
9. Procedure
9.1 Test Sample and Viscometric Cell Preparation:
9.1.1 With the viscometric cells clean and at ambient temperature, remove the nine rotors.
9.1.2 Place a 10 6 1 mL oil sample in each cup.
9.1.3 Install the rotors in the proper stators and install the upper pivots.
9.1.4 Place one of the loops in the 700-mm long string over the crossarm at the top of the rotor shaft and wind all but 200 mm
of the length of the string around the shaft. Loop the remaining end of the string over the top bearing cover. Make sure that the
marked (red) end of the crossarm at the top of the rotor shaft points to the rear of the viscometer unit.
TABLE 1 Ten-Hour Cooling Temperatures—Time for Cooling
to−20°C
Time, h Temperature, °C Time, h Temperature, °C
12.3 6 5.0 6 −16.7 6 0.7
2 −5.9 6 3.0 7 −17.8 6 0.5
3 −10.4 6 2.0 8 −18.7 6 0.3
4 −13.2 6 1.5 9 −19.4 6 0.3
5 −15.2 6 1.0 10 −20.0 6 0.3
D 3829 – 02 (2007)
9.1.5 Placethehousingcoverinplacetominimizetheformationoffrostonthecoldmetalpartsexposedtoair.Iffrostformation
persists, a small container of a desiccant such as Drierite may be placed under the cover to absorb excess moisture.
9.1.6 Turn the switch to HEAT to preheat the oil sample to 80 6 3°C. The rate of increase of temperature is approximately
3°C/min. Hold the temperature of the oil at this temperature for2hto allow solution of any material not in true solution at room
temperature.
9.1.7 Set the temperature control ten-turn dial to the test temperature desired (see Section 8), turn the reset knob to the extreme
clockwise position, turn the switch to COOL, and record the time as start of 16-h conditioning period.
9.1.8 At the end of the 16-h conditioning period record the thermometer reading (test temperature) and remove the cover of the
viscometercellnotinganycalibrationcorrectionstothethermometerreading.Eveniftheanticipatedtesttemperaturehasnotbeen
precisely achieved, do not adjust the temperature control. Proceed to measure yield stress and viscosity at that temperature (9.2
and 9.3).
9.2 Measurement of the Yield Stress :
9.2.1 Beginning with the cell farthest to the left of the instrument, ru
...
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