کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
591764 | 1453881 | 2016 | 7 صفحه PDF | دانلود رایگان |
• A starch paste is subjected to squeeze flow.
• The sample retains memory of loading history.
• Complex modulus of the fluid on dynamic loading is also studied.
• The system is modelled as a visco-elastic three parameter solid.
• Generalised calculus is incorporated to reproduce observed oscillation in strain.
In this work gelatinised potato starch is shown to retain the memory of past loading history. It exhibits a visco-elastic response which does not depend solely on instantaneous conditions. A simple squeeze flow experiment is performed, where loading is done in two steps with a time lag τ∼ seconds between the steps. The effect on the strain, of varying τ is reproduced by a three element visco-elastic solid model. Complexity is introduced through a generalised calculus approach by incorporating a non-integer order time derivative in the viscosity equation. A strain hardening proportional to the time lag between the two loading steps is also incorporated. This model reproduces the three salient features observed in the experiment, namely – the memory effect, slight initial oscillations in the strain as well as the long-time solid-like response. Dynamic visco-elasticity of the sample is also reported.
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Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Volume 492, 5 March 2016, Pages 47–53