Rheology's+learning

26/7/2010 --> edited by: AISHAH mohd marsin After 3 hours lecture, i would like to sum up what did i understand from the learning in Prof Karim's properties of food physical class...

 Rheology is based on the relationship between strain and stress  but...........now i know that any material would behave as liquid or solid depends on TIME/ FREQUENCY....!!!  then...the standard definition of rheology is it is

science of deformation and flow of a material from this statement, i do understands that any movements which deform first then flow is rheology for example~ the change in dimension of material (squeeze, push, pull,step).

some of the common example on our daily life is //**weissenberg effect**//...~  <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">The **Weissenberg effect** is a common phenomenon that occurs when a spinning rod is placed into <span style="color: #000000; display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">a [|solution] of [|liquid] [|polymer]. Instead of being thrown outward, entanglements cause the polymer chains to be drawn towards the rod. It is named after [|Karl Weissenberg]. <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Technically, it is due to a non-zero first normal stress difference. The strain tensor of the motion of turning the rod produces a non-zero difference between the normal components of the resulting stress tensor – so there is a force up /down.

[|Non-Newtonian] fluid is also mentioned in the video.---Yishen Tey:-)]
<span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">then i know about //**shear rate**// <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;"> <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">shear rate is the rate which shear is applied. <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Shear rate for a fluid flowing between two fixed parallel plates is defined using the following equation: <span style="background-color: #ffff00; font-family: 'Comic Sans MS',cursive; font-size: 120%;"> <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">then..other example when //**painting wall**//....based on the gravity effect, the paint will flow down which called sagging...

<span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">rheology

<span style="color: #ffff00; display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">action <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">: the smooth flow of material <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">rheology <span style="color: #ffff00; display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">**inaction:** <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">too thick and too viscous

<span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">~ rheological measurements can provide a rapid determination of product quality & may serve as a tool for quality control

<span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">﻿The term "rheology" comes from the

<span style="color: #0000ff; display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Greek 'rheos' which means 'to flow' <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">or from Heraclitus 'panta rei' which means everything will flow (even solid) but <span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">it is a matter of time if we can wait long enough...!!!!

<span style="color: #800000; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%;">We measure the rheology by based on material that control their deformation and flow behavior subjected external force

<span style="color: #800000; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%;">take notes of this....external force is mainly about the physical outcomes such as push, pull or hit

<span style="color: #800000; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%;">while internal force is mainly about the transient force such as van der wall, hydrogen bond or hydrophobic interaction.

everything CANNOT be deformed without external force....!!!!!

<span style="display: block; font-family: 'Comic Sans MS',cursive; font-size: 110%;">the //conclusion// is....everyday our daily life are based on rheology as long as the food that we eat will be flow and deform...

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