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This article numerically investigates the mixed convection of Bingham fluid in a narrow annulus. The temperature of the inner fixed cylinder ( θ i ) is higher than that of the outer one ( θ o ), which rotates at a constant angular velocity. An OpenFOAM solver, icoFoam, which works based on the finite volume method and the PISO algorithm, is modified to perform the simulations. The modified solver can solve unsteady heat transfer problems for Bingham fluids without using regularization methods. After validating the solver, it solves the problem in different conditions to show the effect of relevant parameters, such as Reynolds number, Bingham number, and aspect ratio, on the flow field and thermal performance of the enclosure for constant amounts of Grashof and Prandtl numbers. The results are presented as streamlines and isotherms, the size and shape of the unyielded regions, the local and mean Nusselt number, and the torque coefficient. The results demonstrate that the flow is steady at Re = 10 for all Bingham numbers, and a decrease in the Reynolds number may result in an unsteady flow depending on the value of the Bingham number. The flow's time history reveals that at a fixed Reynolds number, the flow shifts from periodic to steady-state by enhancing the Bingham number so that the flow becomes entirely steady for a given Bingham number. An interesting phenomenon is observed, the formation, movement, and disappearance of the plug zones (unyielded regions) for the periodic flow at Re = 1 and Bn = 5. [ABSTRACT FROM AUTHOR]

The present study aims to explore and explain the collapse of Pahlavi II using the destabilizing state theory. The reasons for the collapse of the said government have been analyzed based on historical documents and the destabilizing state theory. The paper portrays the subject by scrutinizing historical reasons and evidence found in credible sources. The fundamental issue is the identification of factors and explaining their role in the collapse. The indicators of the destabilizing state theory have been used to examine and explain various historical data. This research, based on library sources, memoirs, documents, and newspapers, and a descriptive-analytical qualitative method, aims to answer the question of ‘Which variables involved in the collapse of the Pahlavi II government are based on the destabilizing state theory and why did the Pahlavi government collapse?’ The results indicated that the variables involved in the collapse of the Pahlavi regime include: Legitimacy crisis, inefficiency in providing public services, law evasion accompanied by violence, coercion and suppression, infiltration of the SAVAK security forces, foreign interventions, especially by the United States, demographic pressure, migration from villages to cities and particularly to Tehran, superiority and decisiveness of revolutionary forces, undeveloped economic structure, rapid and erratic economic growth, and financial corruption. [ABSTRACT FROM AUTHOR]

Using Spragens's crisis theory, which oversees the understanding of political theories, the present article has explained the question of the development process and the nature of "constitutional theory" in Iran during the Qajar era. The purpose of this research is to apply Spragens's theory to understand the nature and explain the development process of constitutional theory in Iran. The results obtained from this research, based on the descriptive-explanatory method, show that the constitutionalism theory did not emerge in the last days of the movement; Rather, it has had a historical-evolutionary process. Regarding its nature, it can be said that the theory of constitutionalism was "the theory of the rule of law" and a movement to "establish freedom" and get rid of tyranny. The development process of this theory by using the theoretical approach of Spragens in the four steps of the problem and observation of disorder; causes of disorder; order and fantasy (rebuilding society); And the prescription phase will be explained. [ABSTRACT FROM AUTHOR]

The unique thermal energy storage system (TESS) as an auxiliary system of solar water heater has a critical part to demonstration in preserving and efficiently utilizing energy, resolving demand-supply mismatches, and boosting the efficiency of energy systems. In this research, a suitable Nano enhanced-Composite Phase Change Material (NCPCM) was prepared to utilize in two model of metal cylinders. First of all, an experimental test for determination of melting point has been investigated by temperature variation test (TVT) method for NCPCM based on paraffin component. Then, two nanomaterial types (TiO2 and CuO) mixed at 50%/50% with two concentrations (0.6% and 0.12%) were dispersed with slack paraffin to provide a total of four experiments to compare the average temperature evolution and exergy efficiency. A theoretical framework for exergy analysis give away that use of nano composites in PCMs will improve efficiency rather than a single nanomaterial. However, to assess capability of this system to integrate with solar water heater, if there is no solar radiation limitation, NCPCM with 1.2% wt. will be a better choice with higher cylinders diameter (HD-Cylinders). Neverthless, for climates with limited time in storage energy, NCPCM with 1.2% wt. and lower cylinders diameter (LD-Cylinders) is our best suggestion for maximum efficiency that can be used during the peak solar energy period. Therefore, by considering NCPCM and integrating this novel study with solar technologies as a reliable heat source, outline is an excellent way for saving energy consumption in buildings at any remote area. [ABSTRACT FROM AUTHOR]

Background and Objectives: Bacterial resistance to antibiotics has motivated the researchers to evaluate the novel anti-bacterial compounds such as some thiazole and imidazole derivatives. Thereby, in this work, we investigated the anti-bacterial effects of one new thiazole and two new imidazole derivatives on Bacillus cereus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium, Proteus mirabilis and Shigella dysenteriae. Materials and Methods: The thiazole and imidazole derivatives were dissolved in DMSO. The disk diffusion method was utilized to measure the growth inhibition zone diameter values, and the broth micro-dilution method was applied to determine the minimum inhibitory concentration (MIC) values. Results: The synthesized imidazole derivatives lacked any inhibitory effect against the tested bacteria. On the other hand, although the synthesized thiazole derivative showed no inhibitory effect against Bacillus cereus, Salmonella typhimurium, and Escherichia coli, it inhibited the growth of Proteus mirabilis, Shigella dysenteriae, and Listeria monocytogenes with the MIC values of 1000, 125, and 1000 µg/ml, respectively, and the growth inhibition zone diameter values of 9.3 ± 0.1, 15.6 ± 0.2, and 8.1 ± 0.0 mm, respectively. Conclusion: The anti-bacterial effect of the synthesized thiazole derivative on Shigella dysenteriae, Proteus mirabilis and Listeria monocytogenes was proven. However, its inhibition effect against Shigella dysenteriae was more than that against the others. Many in-vitro and in-vivo experiments are required to evaluate the effects of this compound on the bacteria and the human body. [ABSTRACT FROM AUTHOR]

Background and Objectives: Antibiotic resistance in bacteria has actuated researchers toward evaluating many new antibacterial compounds of which are the thiazoles. In this research the inhibitory effects of novel thiazole derivatives were unraveled on Staphylococcus aureus, Streptococcus agalactiae, Pseudomonas aeruginosa and Klebsiella pneumoniae and oxothiazole liver toxicity effects were assessed on mice. Methods: The antibacterial effect of thiazole derivatives was evaluated by measuring the halo zone with disk diffusion method and dilution procedure in microplate in order to discriminate the minimum inhibitory concentration (MIC) and the liver toxicity of oxothiazole, also, was discerned by injecting 160 mg/kg, 265 mg/ kg and 350 mg/kg doses to mice as well as scrutinizing the liver histopathology. Results: Derivatives utilized in experiment had no inhibitory effect on Pseudomonas aeruginosa and Klebsiella pneumoniae, though their inhibitory effect was observed on Staphylococcus aureus and Streptococcus agalactiae. For Staphylococcus aureus and Streptococcus agalactiae the diameters of growth inhibition zone were 8.9-22.3 mm and 16.1-25.6 mm, respectively and MIC of 50-200 and 25-100 µg/ml by order. Additionally, by increasing the injection dose of oxothiazole with 160 mg/ml, 265 mg/ml and 350 mg/ml doses, the hepatitis lesions and liver necrosis were observed in experimental mice. Discussion: The thiazole derivatives possessed more inhibitory trace on gram positive bacteria than gram negative ones. Furthermore, the likely presence of oxygen link to thiazole ring in tested compounds results in the enhancement of inhibitory potency of these substances. Besides, our results suggest that high doses of oxothiazole cause severe liver damage and rapid death less than 24 hours. [ABSTRACT FROM AUTHOR]