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In the present study, the effect of attack angle of triangular ribs, by using finite volume method, has been numerically studied in a two-dimensional microchannel. The cooling fluid is water/Ag nanofluid with volume fractions of 0–4% of nanoparticles, and nanoparticle diameters are 25, 50 and 75 nm. The nanofluid flow has been considered as laminar with Reynolds numbers of 5, 100 and 500. Also, the attack angles have been studied at the range of 30°–60°. In this study, the effects of variations in attack angles on triangular ribs, volume fraction of nanoparticles, nanoparticles diameter and Reynolds number have been investigated. The results indicate that using nanoparticles with smaller diameter improves heat transfer rate. Moreover, it is shown that the friction coefficient and pumping power are almost independent of nanoparticle diameter. However, increasing Reynolds number, pumping power enhancement becomes more important by increasing the volume fraction of nanoparticles. In low Reynolds numbers, the influence of ribs is approximately insignificant on the streamlines; it is very effective in high Reynolds numbers. The existence of rib on the direction of fluid motion causes asymmetrical velocity profile in the top section of the rib. Using triangular rib with higher attack angle can improve heat transfer significantly due to the high-velocity gradients and better mixing of fluid flow. [ABSTRACT FROM AUTHOR]

The present research demonstrates a novel 1D photonic crystal (PhC) based reconfigurable biosensor pertaining to label-free detection of different concentrations of progesterone and estradiol, which play a vital role in developing reproductive hormones in women. The proposed sensor is designed by an alternative arrangement of Na 3 AlF 6 and CeO 2 , with a central defect layer. A thin layer of novel phase change chalcogenide material (Ge 2 Sb 2 Te 5 ) is deposited along the two sides of the defect layer to improve the sensing performance. Numerical simulation of transmission spectrum for TE mode is carried out by using the transfer matrix method (TMM). The mainstay of this research is centered on the assay of shift in the defect mode position and intensity with respect to different concentrations of analyte, by changing the phase of the GST material from amorphous to crystalline. Interestingly, we observed a high tunability in defect mode wavelength, when the phase is changed from amorphous to crystalline, which leads to accomplishment of a high sensitivity of 1.75 nm/nmol/L for progesterone and 20.5 nm/nmol/L for estradiol. Aside from sensitivity, other significant parameters like figure of merit and detection limit are computed, which give a deep insight into the sensing performance. These encouraging sensing performances pave the path for efficient detection of different concentrations of progesterone and estradiol to monitor various gynecological problems in women.

In this study, we investigate optical properties of metal nanoparticle crystals fabricated by implanting copper (Cu) ions into single silica (SiO2) crystals with 400keV at various ion doses. The Cu implanted SiO2 (SiO2:Cu) crystal produces a broadband luminescence emission, ranging from blue to yellow, and having a blue luminescence peak at 546nm. Such anomalous luminescence emission bands suggest that the ion implantation may give rise to aggregation of Cu nanoparticles in the host matrix. The boundary element method-based modelling of a given Cu nanoparticle aggregation was employed to justify the broadband luminescence emission. Formation of Cu nanoparticles in SiO2 is predicted through their optical absorption data. The experimental results are compared with results of Mie calculations and we observe that the higher ion dose produces the larger particle size., (Copyright © 2016 Elsevier Ltd. All rights reserved.)