This paper proposes a new method for the design of a broadband dual-beam reflectarray antenna with a single feed. This method is based on the producing a null in the antenna radiation pattern and the appearance of two beams. The reflection phase distribution on the aperture of the antenna has been studied to achieve this null. A single layer subwavelength element with multi-resonances is used as the phase shifting unit cell due to its wide linear phase range. A comprehensive theoretical analysis and full-wave simulation are accomplished and the results are in good agreement. Two dual beam reflectarray antennas operating at X band are designed using the proposed method and the geometrical method. The improvement in the gain bandwidth and the beam squint of the designed reflectarray using our proposed method is observed compared to the other one. The simulation results show the improvement of 1. 1% in 1-dB gain bandwidth and in the beam squint for the proposed design method compared with the other one.

The focus on different energy harvesting methods has led to various studies on the mechanism of flow-induced vibration phenomena, including vortex-induced vibration, galloping, and wake-galloping. In this study, an experimental investigation on flow around a cylinder with an elastic cantilever beam has been conducted to develop new energy harvesting devices based on its dynamic behavior. Therefore, the basic principles for the design of a high resolution open-circuit subsonic wind tunnel were systematically studied and a specific small scale wind tunnel was constructed based on the requirements. The test chamber cross section for the designed wind tunnel is square with a side length of 50 centimeters which can be used for investigation of different micro wind turbines performance up to velocity of 8 m/s with resolution of less than 0. 1 m/s. The vibration of two prototype micro-turbines in the presence of obstacles and without obstacles has been studied in different Reynolds numbers. The results show that a circular cylinder oscillates with larger amplitude in the VIV range in comparison to the square cylinder, however, when galloping starts by increasing Reynolds number, the oscillation amplitude of the square cylinder severely increases. The experimental findings show that the presence of an obstacle in upstream of the flow considerably increases the amplitude of oscillation, however, does not have a meaningful effect on the vibration frequency. Also, results indicate that the vibration amplitude of the bluff body in the wake-galloping phenomenon for the square obstacle is greater in comparison to the circular obstacle.

In this study, a piezoelectric cantilever beam energy harvester model with two exponential cross-sections in width and thickness, and a tip weight, was proposed for use in a tire pressure monitoring system (TPMS). The governing equations for energy harvesting were derived for the first time for an exponential cross-section beam under rotational tire excitation conditions, based on the Euler-Lagrange method and coupled with electrical relations. There are few studies that consider both the thickness and width of the beam as variables, and no theoretical research has been conducted on this model under rotational excitation of the tire. The results of this study showed that it is possible to harvest energy by using a beam with an exponential cross section in width and thickness that can be designed with less weight and more electrical power. In future research, the derived equations can be used for optimization to increase electrical power and reduce weight to find the optimal values of the model's geometric dimensions.

Introduction: While human endothelial progenitor cells (EPCs) have been a subject of somehow extensive investigation, EPCs from adult mouse hematopoietic system were poorly studied. Present investigation is focused on FVB mouse endothelial progenitor cells in terms of their isolation, purification, and expansion. Materials and Methods: Mononuclear cells collected from murine peripheral blood were cultured in fibronectin coated plate for two weeks, at which point, the adherent cell population were lifted and analyzed in terms of some surface markers. Using FACS Vantage equipped with one-cell deposition unit, single CD34 positive cells were plated per well already containing medium optimized for single cell growth. Several clones were then emerged, expanded, and examined in terms of some surface markers. Furthermore, the cells were investigated regarding ability to uptake DiI-ac-LDL and form capillary network on matrigel surfaces. Results: Adherent population of mononuclear cells from mouse peripheral blood was appeared morphologically heterogeneous. About 5% of the adherent cells were CD34 positive. Having optimized their culture condition, several CD34 positive clones were expanded. The cells comprising the clones were DiI-ac-LDL+ and formed capillary-like tube when being seeded on matrigel surfaces. Conclusion: The primary culture of the mononuclear cells from murine peripheral blood contains a very limited number of cells positive for endothelial lineage markers. These cells (adherent CD34 positive) could be expanded by single cell cloning technique.

Aluminum nitride (AlN) thin films have potential applications in microelectronic and optoelectronic devices. In this study, AlN thin films with different thicknesses were deposited on silicon substrate by single ion beam sputtering method. The X-ray diffraction (XRD) spectra revealed that the structure of films with thickness of 50-150 nm was amorphous, while the polycrystalline hexagonal AlN with a rough surface was observed at a thickness of 300 nm. Also, the formation of AlN in amorphous films is identified by Fourier transform infrared (FTIR) spectroscopy. Atomic force microscopy (AFM) study confirms that the surface roughness and average grain size of films increased with film thickness.