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Lab Viscometer Manual Glossary

Amplitude Sweep
An oscillatory test where strain or stress amplitude is incrementally increased or decreased while maintaining a constant frequency, used to determine yield and flow points

Angular Frequency
Rate of the oscillation or phase change of a waveform, measured in radians per second, used in dynamic rheological testing

Automatic Gap Control/ Automatic Gap Setting
Feature that adjusts the distance between the spindle and the measurement plate automatically for precise sample testing

Barcode Reader
An integrated system in rheometers that automatically recognizes spindles and measuring systems by scanning barcodes

Brabender Units
Specific measurement units used in ASTM C474 testing

Bubble Level Tool
A device included with the RSO Rheometer to ensure the instrument is level for accurate measurements

Casson Model
Rheological model describes non-Newtonian flow behavior after yielding, used for determining yield stress and plastic viscosity, particularly in materials like chocolate

Coaxial Cylinder (CC) / Coaxial Cylinder Mode (CC Mode)
A measurement geometry ideal for low-viscosity samples, offering high accuracy

Cone and Plate System Mode
Configuration for testing small samples or materials with high shear rates using cone or plate spindles

Controlled Deformation (CD)
An oscillatory measurement mode where deformation is precisely controlled

Controlled Shear Stress (CSS)
A test mode where the shear rate is maintained constant while monitoring stress responses

Creep Recovery
Two-phased test to evaluate viscoelastic properties by applying stress and observing deformation during loading and recovery after stress removal

Double Gap System (DG)
A coaxial cylinder geometry designed for low-viscosity measurements with increased sensitivity

Dynamic Drive System
A mechanism enabling precise rotational and oscillatory measurements in the RSO Rheometer

Elastic Modulus (G’)
Represents a material’s elastic (solid-like) behavior during oscillatory tests

Elastic Portion
Percentage of a material’s deformation that is recoverable after stress removal during a creep recover test

External Mode
Allows the rheometer to be operated vis Rheo3000 software for advanced control and analysis

FTKY3 / FTKY3 Water Jacket
Interface or function for setting test parameters like spindles, speed, end conditions, and data collection preferences

Frequency Sweep
An oscillatory test where the frequency is varied while keeping stress or strain constant, used to analyze viscoelastic properties

Gap Drive
Mechanism in rheometers for setting sample gaps in cone-plate or plate-plate geometries

Gap Height
Adjustable distance between the spindle and the measurement plate, crucial for accurate viscosity measurements

High Shear Step
Part of thixotropy testing used to break a sample’s internal structure and evaluate recovery

Immersion Feature
Automatic or manual positioning of spindles to ensure consistent sample testing

Low Shear Step
Used in thixotropy tests to measure a material’s baseline viscosity before structural breakdown

Loss Modulus (G”)
Represents a material’s viscous (liquid-like) behavior oscillatory tests

Measuring System
Refers to the specific spindles and accessories used with the rheometer for various sample types

Moment of Inertia Calibration
Calibration procedure for spindles to ensure accurate oscillatory measurements

Motor Friction Calibration  
Calibration procedure for spindles to ensure accuracy at low torque settings

NCA/CMA Casson Model
Standard rheological model for chocolate, measuring yield stress and plastic viscosity

Oscillation Measurement / Oscillatory Testing  
A test mode used to evaluate viscoelastic properties by applying stress or strain

Peltier Plate (PA)
Built-in temperature control system in rheometers, operating from -20°C to 180°C

Plastic Viscosity  
Steady-state viscosity of a material after yielding, determined by using rheological models like the Bingham or Casson models

RSX-CC
A coaxial cylinder rheometer for single-point quality control or complete rheological profiling

RSX-CPS
A cone/plate and plate/plate rheometer with precise temperature control and automated gap settings

RSX-SST
A rheometer designed for materials like slurries and pastes, capable of automated immersion

Shear Rate
Rate of deformation caused by applied shear stress, measured in s⁻¹

Shear Stress
Force per unit area required to deform a material, measured in Pascals

Storage Modulus (G’) (IP30)
Parameter indicating the elastic (solid-like) behavior of a material under oscillatory stress

Temperature-Dependent Behavior
Analysis of how a material’s properties change with temperature under constant oscillatory stress

Thixotropy
A time-dependent decrease in viscosity under constant shear, followed by recovery upon stress reduction

Torque
A measure of rotational force applied during testing, essential for calculating viscosity

Touchscreen Interface Mode
A resistive screen used for operating the RSO Rheometer, supporting touch inputs for navigation and data entry

Viscous Portion
A measure of a fluid’s resistance to deformation

Yield Stress
Stress required to initiate flow in a material, often evaluated using controlled stress tests

Zero Gap Setting
A calibration step in rheometers to ensure precise measurement geometries