![]() Emulsions can show a different rheological behavior in a continuous temperature change because the temperature effects on the droplets can accumulate in the system. This lack of clarity exists despite the fact that temperature change is the condition that emulsions may commonly experience in industrial settings. 24–26 However, it is not clear how the transition occurs when the temperature continuously increases or decreases. 23 There have been many experimental and numerical studies explaining trends of rheological properties in different isothermal systems. 22 A maximum in the height of the first peak of the pair-correlation function shifts to higher packing fractions as the temperature is increased from zero. 21 The temperature becomes independent of the shear rate for a sufficiently slow shear, which suggests that it is an effective temperature for the jammed packing. 21–23 Scaling of the shear modulus of gel captures the temperature dependence of the shear modulus for different particle sizes and batches entirely within the threshold volume fraction. ![]() ![]() The dependency of the temperature on the transition has also been studied. 11 Non-Newtonian behavior below the jamming concentration and yield-stress behavior above it was found. 9,10 By rescaling the shear stress and shear rate, it is possible to obtain master curves for the flow properties both above and below the jamming with a continuous transition between the two in the shear thinning region. 8 Flow curves for the unjammed and jammed states are theoretically described by the Herschel–Bulkley equation and a cross-type equation, respectively. 7 By continuously and uniformly increasing the packing fraction of a quasi-two-dimensional granular system, a structure signature, which is shown as the maximum of the height of the first peaks of the pair correlation function, was found through the zero-temperature jamming point. 6 As the volume fraction decreases toward the onset of unjamming, the density of vibrational states approaches a nonzero value in the limit of zero frequency. 6–20 At the moment, the volume fraction of a system reaches the jamming threshold-the critical volume fraction-the bulk and shear moduli simultaneously become nonzero, and the distribution of the critical volume fraction values becomes narrower as the system size increases. The effects of the volume fraction on the jamming or unjamming transition have attracted considerable interest in many studies. When increasing the volume fraction, or decreasing the shear stress and temperature, systems tend to go from unjammed to jammed states. Three parameters influence the jammed states: volume fraction, shear stress, and temperature. However, the elastic modulus becomes nonzero for a solid-like jammed system because the phase lag is between 0° and 90°, which means that a system deformed by external forces has a tendency to recover its original shape when the forces are removed. For liquid, the elastic modulus is zero because the phase lag is 90°. The elastic modulus, determined by the phase lag between strain and stress under oscillatory shear flow, is one factor that can analyze the transition. 1–3 Especially, the rheological properties of blood as a colloidal suspension have great effects on the blood pressure and wall shear stress related to the cardiovascular diseases. Understanding the mechanism of this transition is of great interest in many research areas in the food, polymer, biomedical, and lubrication industries. ![]() A broad range of rheological materials, such as foams, granular materials, emulsions, and colloidal suspensions, can undergo a transition between a flowing liquid-like (unjammed) state and a nonequilibrium disordered solid (jammed) state. ![]()
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