The MICROTUBEs are important structures in nanoelectromechanical systems. In this study a nonlocal model is presented to investigate the static torsion behavior of MICROTUBEs made of bi-directional factionally graded material (BDFGM) subjected to a longitudinal magnetic field. Mechanical properties of BDFGM MICROTUBE varies in the radial and longitudinal direction according to an arbitrary function. The governing equation is obtained using the principle of minimum potential energy. a sinusoidal distributed torque and uniform magnetic field with clamped boundary condition are considered to capture the effects of nonlocal parameter, FGM indexes and intensity of longitudinal magnetic field on the torsional angle of BDFGM MICROTUBE. The numerical solution of generalized differential quadrature (GDQ) is compared with Galerkin method which a reasonable agreement is observed. Result indicates that intensity of the longitudinal magnetic field has important role on the torsional angle of MICROTUBEs such that when intensity of longitudinal magnetic field increases the torsional angle of MICROTUBEs decreases. 1

This study aimed at investigating liquid-liquid extraction of the three-component n-hexane + benzene + sulfolane system in a micro extractor. Experiments were carried out in a MICROTUBE with a diameter of 800μ m using a T-shaped micromixer at a residence time of 15s. Temperature and the ratio of solvent (sulfolane) to feed (95% n-hexane + 5% benzene) investigated as operational variables. The temperature was investigated at (313. 15, 323. 15, and 333. 15) K, and the solvent to feed ratio was investigated in five states including (0. 33, 0. 50, 1. 00, 2. 00, and 3. 00) mL/mL. The results of experimental design and statistical analysis showed that operational variables had a significant impact on the distribution coefficient and selectivity. It was found that distribution coefficient and selectivity reached their highest levels at (313. 15 and 32315) K, respectively. In addition, in the low volumetric solvent to feed ratio (0. 33ml/ml), the highest levels of distribution coefficient and selectivity were been obtained. Finally, the results obtained for liquid-liquid extraction of n-hexane + benzene + sulfolane were assessed using NRTL and UNIQUAC models, and the results confirmed the high accuracy of both models.

Decreasing pressure losses in MICROTUBEs is an important subject, especially when an increase in the flow capacity is required. In the same pumping power, decreasing the pressure drops coincides with increasing the fluid flow rate passing through a MICROTUBE. The current study aims to examine how the water pressure drop across a MICROTUBE can be affected by the addition of small concentrations of different drag-reducing polymeric agents. A kind of the laminarization behaviour was found by the addition of the selected polymer to the turbulent flow. The effect of the concentration of the drag-reducing agent (DRA) on the observed viscosity and drag values are reported. Moreover, the effects of different types of drag-reducing agents on the friction factor are obtained at the best concentration in the range of examined concentrations. Under this condition the percentage of the drag reduction and increase in the capacity of the flow were respectively 33 % and 36 %. The obtained results show that more drag reduction occurs at a higher flow rate for 20 ppm of the polyacrylamide with a high molecular weight.

Introduction: Valproic acid (VPA) is an antiepileptic drug used to treat epilepsy and bipolar disorder. Adverse effects of VPA were studied in many reports, however, a dose-response relationship between VPA and its metabolites in epilepsy patients are extremely limited. In this paper, a high efficient method was developed for the preconcentration and determination of VPA and its main metabolite in plasma. Methods: For the extraction and preconcentration of the selected analytes, a volume of an extractant was placed at the bottom of the MICROTUBE containing pretreated plasma. The mixture was repeatedly withdrawn from the MICROTUBE and pushed-out into it using a 1. 0-mL glass syringe and resulted in a cloudy mixture. For further turbidity, the mixture was shaken on a vortex agitator. This procedure was used to analyze the plasma samples of patients with epilepsy (n = 70). Results: The results revealed that in most patients with a low level of VPA relative to its expected level, 3-heptanone concentrations were high. The limits of quantification of 3-heptanone and VPA were 0. 04 mg L– 1 and 0. 2 mg L– 1, respectively. A suitable precision at a concentration of 2 mg L-1 for each analyte was obtained (relative standard deviation ≤ 9%). Conclusion: The obtained results indicated that this procedure is easy, sensitive, and reliable, and can be used for the analysis of the selected analytes in the plasma samples of patients with epilepsy.