The modifying of the rheological properties of pure bitumen to improve the performance of Asphalt mixtures has attracted many researchers in recent decades. The purpose of this study is to investigate the effect of Gilsonit on rheological properties of pure bitumen .For this purpose, different percentages of Gilsonite powder were used to modify the rheological properties of pure bitumen 60/70 .In the study of rheology of bitumen (modified and unmodified), viscosity test, softening point, penetration test and flash point were performed, in addition to, the thermal sensitivity of the bitumen was calculated. The results of this study indicate that the addition of Gilsonite to pure bitumen increases the viscosity and softening point and the penetration index of bitumen decreased. Also, Gilsonite improves the thermal sensitivity of pure bitumen, but this bitumen powder has no effect on the flash point. Gilsonite and bitumen used in this research are from the mine of Ilam province and the Pasargad oil refinery, respectively.

Chitosan – Poly (N-isopropylacrylamide) hydrogels were synthesized by thermal and gamma irradiation methods. In the thermal method، initiators and crosslinkers were employed. It was found that the gamma irradiation method produced hydrogels of higher water swelling ratio. The hydrogels were used in drilling fluids and the important rheological properties of the muds such as apparent viscosity، plastic viscosity، and yield point as well as shear-shear rate diagrams were measured. Obtained results show that whereas linear polymer effects on mud properties are more significant in lower polymer concentrations، prepared crosslinked hydrogel effects are more significant at high concentrations. The hydrogel synthesized by gamma irradiation improved rheological properties of drilling fluids at higher concentrations of the hydrogel more effectively than the thermally produced hydrogel and linear polymers. It seems that addition of hydrogel to mud in powder form can increase the effects of rheological properties of drilling fluid. Thus، increase in gamma irradiation dose and monomer concentration، which rendered high swelling hydrogels، were more suitable for improving properties of drilling muds. In thermally synthesized hydrogels، increase in monomer and decrease in crosslinker concentration produced better hydrogels.

Considering the rapid progress in applications of membrane separation technologies in various industries and the importance of asymmetric membranes morphology in governing the separation performance in membrane systems, control of this parameter in the membrane fabrication process is regarded as a prominent subject in the field. Hence, investigation on the rheological properties of polymer solutions, including viscoelasticity and gelation behavior and their influence on the membrane formation and morphological structure of membranes including flat sheet and hollow fiber membranes is a prerequisite to produce asymmetric membranes with desirable characteristics. Phase inversion is the most widely used technique for the preparation of asymmetric membranes and the two major mechanisms of liquid-liquid and solid-liquid demixing in membrane fabrication process affect the morphology of the membranes. Therefore, controlling the phase inversion in the early stage can greatly influence membrane microstructure. The rheological behavior of polymer solutions during the fabrication of membranes as well as other factors that influence the morphological structure of the membranes are evaluated in the present study. In addition, the principles governing the rheology of polymer solutions such as viscoelasticity, shear and extensional viscosity play a crucial role in determining the membrane morphology and separation performance. Due to the interaction of the rheology of polymer solutions and phase inversion, the effects of changes in the rheological properties on the phase inversion and the formation of membranes with different structures and morphologies are studied. Furthermore, in addition to the analysis of the effect of the relaxation time and gelation mechanisms, discussions are provided about the determination of the final membrane morphology considering the competition between the domains growth and gelation rates.

Several studies have been done on the rheological properties and setting time of cementitious mixes, but the relationship between these two important features has not been studied so far. Therefore, the aim of this study is to investigate the relationship between rheological properties and setting time in self-consolidating concrete mixtures. In this study, six self- consolidating concrete mixture proportions were considered, in which the effect of water-cement ratio changes, silica fume and slag was used. The electrical resistivity method has been used in determining its setting time, and the performance of this method has been evaluated in determining the rheological properties. Since the electrical resistivity method is not standardized in determining the setting time, therefore, to verify the results, the standard penetration resistance method is also used according to the ASTM-C403. In the study of rheological properties, the studies have been done in two sections of efficiency and rheometer analysis. From the results, it was found that mixtures that have higher slump flow have recorded less time to take. It was also found that concrete mixtures that have higher yield stress (static and dynamic)  have shorter setting time. In this way, the relationships between these two important variables (rheological properties and setting time) were evaluated by the relationships.

based drilling fluid, rheology modifier and enhanced oil recovery. Moreover, structure and microstructure of these polymers are of important in above-mentioned applications. Acrylamide homopolymer and acrylamide/styrene copolymer were synthetized using micellar polymerization for application in the water-based drilling fluid. FTIR, NMR and some theoretical calculations were used to characterize (micro)structure of the polymers. In addition, conversion was obtained using gravimetric method. Ubbelohde viscometer was used to evaluate viscosity- average molecular weight. Apparent viscosity was measured by Brookfield viscometer. Synthesized polymers were used in the water- based drilling fluids with three different concentrations and rheological and fluid loss properties were evaluated before and after hot rolling at 120 °C for 16 h. Moreover, FTIR and NMR results showed successful synthesis of the homo- and copolymers with high conversions. Average hydrophobic styrene block length was calculated by theoretical method to be 3. Results showed that both conversion and molecular weight values were higher in the case of synthetized homopolymer. It was attributed to increase in the possibility of chain transfer to surfactant in the micellar copolymerization reactions. Results showed that despite higher molecular weight in the acrylamide homopolymer case, viscosities of the acrylamide/styrene copolymer aqueous solutions were better in similar concentrations. It was attributed to the hydrophobic association between styrene units. Finally, results showed that both homo- and copolymer caused an improvement in the rheology and fluid loss properties of the water- based drilling fluid. Although rheological properties were reduced after hot rolling or in the presence of salt in the drilling fluids, drilling fluids prepared with acrylamide/styrene copolymer showed more ability to preserve their rheological properties due to the formation of physical network resulting from the hydrophobic associations.

Hypothesis: The dispersion state of nanoparticles cannot be evaluated accurately by rheological and mechanical testes because their agglomerates break down under applied stress leading to changes in their microstructure. Additionally, the contribution of interparticle interactions to macroscopic properties such as rheological and mechanical properties is still unclear. This is mainly due to the combined effects of interparticle interactions and the particle-polymer interactions. Microscopic measurements which can only provide information on a very small section of a sample are not reliable for this purpose. However, electrical tests as nondestructive methods can be used to assess the microstructure and cluster formation in nanocomposite structures. In addition, it is possible to detect separately the effect of filler-filler interactions using dielectric properties and with a proper choice of materials.
In this study, ZnO/polystyrene (PS) nanocomposites were prepared through conventional mixing, dispersive mixing and surface particle treatment to control the particle dispersion states. The dispersion state of nanoparticles has been analyzed using their optical, electrical and rheological properties.
Findings: The results showed that storage modulus increased with increasing filler dispersion, which could be attributed to the increase in interfacial layer and the higher modulus of nanocomposite relative to that of the bulk polymer matrix. The SEM images showed that the dispersive mixing and surface treatment of ZnO nanoparticles with oleic acid improved the dispersion of ZnO particles inside the PS matrix. On the other hand, increase in dispersion decreases the electrical conductivity and dielectric constant due to greater interparticle distance and reduction of dipole-dipole interactions, respectively. Hence, it is possible to detect the particle dispersion state by rheological and electrical properties.

In addition to influential parameters on rheology of Self-compacting concrete such as paste rheology and aggregate properties, paste volume factor can also be mentioned. The paste present in Self-compacting concrete can decrease interparticle friction of aggregates by increasing the distance between them, thus changing the fresh and hardened properties of Self-compacting concrete. Here by keeping the water cement ratio equal to 0.45, aggregates grading, admixture cement ratio percent, vma cement ratio percent fixed and only by changing the consumed paste volume, we assessed the effect of paste volume on workability of eight samples of Self-compacting concrete. Workability of different mixtures were assessed by undergoing slump-flow, j-ring, l-box (without bar), l-box, u-box, v-funnel and v-funnel (after 5 min) tests. Results in the mentioned range show improvement on workability of Self-compacting concrete due to increase of paste volume.

In injection molding process, the feedstock rheological properties are key features which influence the steady flow and the uniform filling into the mold. For this purpose a binder system containing paraffin wax (PW), bees wax (BW), and stearic acid (SA) was selected and flow characteristics of the compound of aforementioned binder and pure Mg-Al2O3 nanocomposite powder via a rotary rheometer at the shear rate of 0.1-1000 s-1 and the temperature of 84 °C, parameters of injection molding and debinding were investigated. The results indicatedaddition of nano Al2O3 till 2.5 wt.% improves rheological behavior. Also, by studying the condition of injection molding and debinding, it reveals that the temperature of 100 °C and pressure of 90bar and a graphite bed under usual atmosphere are suitable.

Effect of temperature and curing agent type parameters on rheological behavior of binder system based on Hydroxyl terminated Polybutadiene (HTPB) is important in the aspect of production for medium and large-size grains. In this research, the effect of casting temperature 40, 50 and 60 ºC) and chemical structure of curing agents (TDI, IPDI and HDI) on rheological behavior of a binder system based on HTPB were investigated. Increasing casting temperature due to curing progress, builds up the viscosity. Therefore, decreasing casting temperature by controlling curing process increases the pot life of binder system. logarithmic variation of viscosity versus time for three binder systems based on TDI, IPDI and HDI at different temperatures implies that binder system based on HTPB-TDI due to aromatic structure of TDI shows the fastest viscosity build up.Moreover binder system based on HTPB-IPDI shows lowest viscosity build up due to aliphatic structure of IPDI.