r. rashidi

Development of nanotechnology and related sciences in the field of lubrication has led to applying nano particles in combination of the common lubricants as one of the most new solutions proposed by the tribology researchers to improve the performance of this type of support systems. In this study, the effect of TiO2 nano particles concentration combined with the base SAE30 oil on the steady state and dynamic stability performance of hydrodynamic two lobe journal bearings is investigated. For this purpose, after modifying the governing Reynolds equation of hydrodynamic lubrication using nano fluid theory and assuming the harmonic limit cycle oscillation of the rotor center around the static equilibrium point based on the linear dynamic model, the stability performance of two lobe bearings are analyzed. Finally, the static and dynamic stability characteristics for different concentration of the nano particle according to the bearing non circularity are obtained using the finite element method (FEM). The results show that the static and stability performance parameters of the non circular two lobe bearings, including the load carrying capacity, coefficient of friction, critical mass of the rotor and the whirl frequency ratio improve by increasing the concentration of TiO2 nano particles added to the base oil, especially for solid volume fraction less than %0.02 and the magnitude of performance variations is also amplified by reducing the amount of bearings non circularity.

As access to mobile phones is growing, dependence on mobile phones is being observed among teenagers and young adults. This study aimed to investigate the relationship between personality traits, loneliness, and identity styles and dependence on mobile phones among students.
This cross-sectional study was conducted on 380 male and female high school students in Qorveh in the academic year 2013-2014. The participants were selected using random cluster sampling. The data were collected by NEO-PI, McCrae and Costa, dependence on mobile phones, Identity Styles Inventory (ISI-6), and loneliness questionnaires. Then, the data were entered into the SPSS statistical software, version 16 and were analyzed using Pearson's correlation coefficient and logistic regression.
The results showed a significant positive correlation between dependence on mobile phones and openness, neuroticism, and loneliness (p The results indicated that dependence on mobile phones could be predicted by analyzing personality traits, identity styles, and feeling of loneliness. Thus, appropriate plans should be designed to perform preventive interventions for such individuals.

Background and Objectives Prevention and treatment of hyperuricemia are based on control of uric acid levels. The aim of this study was to investigate the effect of oral administration of sour cherry and allopurinol on serum uric acid levels biomarkers of oxidative stress (total antioxidant capacity and malondialdehyde concentration) and hepatic xanthine oxidase/xanthine dehydrogenase activity in normal and hyperuricemic rats. Methods A total of 36 male Wistar rats (Weights: 180-200 g) were randomly divided into six equal groups. These groups were normal; normal+cherry tart (5 g/kg); normal+allopurinol (5 mg/kg); hyperuricemic; hyperuricemic+sour cherry (5 g/kg); hyperuricemic+allopurinol (5 mg/kg). Every group received their treatment once a day for 14 days. Hyperuricemia in rats was induced by intraperitoneal injection of potassium oxonate (250 mg/kg). Results Oral administration of sour cherry for 14 days significantly reduced the serum uric acid levels of hyperuricemic rats in a time-dependent manner. Hepatic xanthine oxidase/xanthine dehydrogenase activity was significantly inhibited in both normal and hyperuricemic rats. Oral administration of cherry tart led to a significant improvement in biomarkers of oxidative stress in rats. Although the hypouricemic effect of allopurinol was much higher than that of sour cherry allupurinol could not significantly change oxidative stress biomarkers. Conclusion The results indicate that cherry as a polyphenols-rich food could be used as a possible therapeutic supplement to minimize the side effects of allopurinol in treating hyperuricemia and oxidative stress diseases.