This research aimed to assess and determine RHEOLOGICAL properties of chocolate pistachio produced from various volumes of monoglycoside (1% and 2%), date powders (34, 38 and 42%) and pistachio pastes. The analyses were performed at temperatures of 45oC, 65oC after 3 and 5 hours of processing. These products were found to exhibit non- Newtonian, pseudo-plastic behavior at all treatments. Apparent viscosities versus speed data were successfully fitted to a power law model. The flow behavior index, n, varied in the range of 0.8-0.94. The consistency index, k, was in the range 101.495-167.738 pa - sn. According to statistical analysis, the exponential model was a better model to describe the effect of the soluble solids on the viscosity of chocolate pistachio containing varying percentages of date powder. The activation energy (Ea) was 446.2-41330 j/mol.

To study the RHEOLOGICAL behaviour of Caspian pony blood which is a suspension of macromolecules in an aqueous medium, steady shear and small amplitude oscillatory shear experiments were conducted on thirty Caspian pony blood samples. The seven different viscoelastic constitutive equations viz., Giesekus, Thurston, four-constant Oldroyd, Williams-Bird, Spriggs, modified Spriggs and Bogue-White were examined. The viscosity data obtained from steady shear experiments and the dynamic viscosity and imaginary part of complex viscosity data obtained from oscillatory shear experiments were used to determine the model parameters. The performance of the models was studied by comparing their prediction for viscosity, dynamic viscosity and imaginary part of complex viscosity with those measured experimentally. As a result, Giesekus and Thurston models were found to be the best models and the Caspian pony blood was characterized by these models. The same experiments mentioned above were carried out on four blood samples of one Caspian pony, different only in hematocrit, in order to find its effect on RHEOLOGICAL properties of Caspian pony blood. It was concluded that as the hematocrit of Caspian pony blood increased, the zero shear rate viscosity, the relaxation time, the retardation time and the very high shear rate viscosity increased and the mobility factor decreased.

As a very important coating material in different applications, bitumen is a complex mixture of different chemicals. It is generally accepted that the principle of time-temperature superposition (TTS) holds for this material. In this study RHEOLOGICAL measurements were carried out on four different bitumens. Different representations of the experimental data were examined to check failure or holding of TTS for this complex system. Due to differences in dynamics of components, discontinuities were observed in versus G* curves for all four bitumens. It was concluded that the TTS fails to be applied for the studied bitumens.

In the area of semi-active control of civil structures, Magneto-RHEOLOGICAL (MR) damper has been an efficient mechanism for reducing the seismic response of structures. In this paper, an effective method based on defining an optimization problem for designing MR dampers has been proposed. In the proposed method, the parameters of semi-active control system are determined so that the maximum response of structure is minimized. To solve the optimization problem, the Genetic algorithm (GA) has been utilized. The modified Bouc- Wen model has been used to represent the dynamic behavior of MR damper while to determine the input voltage at any time step, the clipped optimal control algorithm with LQR controller has been applied. To evaluate the performance of the proposed method, a ten-storey shear frame subjected to the El-Centro excitation and for two different kinds of objective functions, optimal MR dampers have been designed. Then the performance of optimal MR damper has been tested under different excitations. The results of the numerical simulations have shown the effectiveness of the proposed method in designing optimal MR dampers that have the capability of reducing the response of the structures up to a significant level. In addition, the effect of selecting a proper objective function to achieve the best performance of MR dampers in decreasing different responses of structure has been shown.

In this work RHEOLOGICAL behavior of polyethylene/polypropylene blends produced by Arak and Bandar Imam Petrochemical complexes was investigated. The viscosity of homopolymers, PE and PP, and their blends at different concentration proportions were measured. The measurements have been carried out by using a capillary rheometer. The results for the blends show that when two homopolymers with great difference in shear viscosity form a blend, the viscosity of the blends are intermediate between the viscosity of homopolymers. On the other hand, for the two homopolymers (PE and PP) with viscosities close to each other, the curve of viscous homopolymer falls down quickly below the viscosity of blends with high shear rate. It has been shown that the viscosity of the blends versus PE content has negative deviation from logarithmic addition rule. The modeling of viscosity of blends in respect to concentration of homopolymers has been produced and it is shown that the modified Kulezner model can predict the viscosity of the blends in terms of viscosities of original resins with very good precision.

In this work, a stable NiFe2O4 paraffin based ferrofluid was prepared via high energy milling. The RHEOLOGICAL properties of ferrofluid were studied. Bingham plastic, Herschel-Bulkley and Casson models were used to evaluate the shear stress-shear rate dependency. The ferrofluid exhibited a shear thinning behaviour for all studied magnetic field. The magneto-viscous effect and thixotropy of ferrofluid were studied and the role of formation and destruction of magnetically induced structures and the interactions of nanoparticles and aggregates were discussed.