The demand for water and energy in today’s developing world is enormous and has become the key to the progress of societies. Many methods have been developed to desalinate water, but energy and environmental constraints have slowed or stopped the growth of many. Capacitive Deionization (CDI) is a very new method that uses porous carbon electrodes with significant potential for low energy desalination. This process is known as deionization by applying a very low voltage of 1.2 volts and removing charged ions and molecules. Using capacitive principles in this method, the absorption phenomenon is facilitated, which is known as capacitive deionization. In the capacitive deionization method, unlike other methods in which water is separated from salt, in this technology, salt, which is a smaller part of this compound, is separated from water and salt solution, which in turn causes less energy consumption. With the advancement of science and the introduction of new porous materials, the use of this method of deionization has increased greatly. Due to the limitations of other methods of desalination, this method has been very popular among researchers and the water desalination industry and needs more scientific research to become more commercial.

Capacitive deionization (CDI) is greatly recommended as a desalination process for its eco-friendly and low energy consuming technique in removing salt ions (NaCl) from salty water. This study reports a Zeolitic Imidazolate Framework-8/Graphene (ZIF-8/G) nanocomposite modified electrode performance in CDI technology. Based on its promising features, like large surface area and good electric conductivity, graphene is an adequate electrode. Interestingly, ZIF-8 is homogeneously well intergrown on the surface of graphene. Hence, electrochemical performance such as electrical conductivity and cyclic voltammetry in CDI unit were examined, and characteristics like the morphology, identification and determining the structure of the prepared materials were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR). As an adsorbent, the prepared ZIF-8/G nanocomposite exhibits the best adsorption capacity about 141.6037 F/g higher than each individually and great electrical conductivity about 672 μs/cm. The high adsorption specific capacity and good reusability of the ZIF-8/G nanocomposite suggests that it can be applied as novel adsorbents showing attractive potential for the CDI technique.

The structural, morphological, linear, and nonlinear optical properties of MoO3 thin films deposited by thermal deposition were measured. The effect of various thicknesses of films was studied. The structural and morphological parameters of films, determined by x-ray diffraction, field emission scanning electron microscopy, and AFM images, are compared to the linear and nonlinear optical characteristics of these media. The bandgap of the prepared thin films was obtained from the diffuse reflectance spectroscopy spectra. The electron’s effective mass (me*/m0), linear refractive index (n0), and optical static and high frequency dielectric constant (ɛ0, ɛ∞) values were calculated by using the bandgap energy values. Increasing the thicknesses of thin films decreased the bandgap, increased the root mean square, and increased the size of nanoparticles and the nonlinear response of thin films. The high magnitude of n2 and β was because of MoO3 (300 nm-thickness), which were of the order of 10−5 cm2/W and 10−1 cm/W, respectively. The fluctuations in nonlinear responses observed at different thicknesses are attributed to d–d transitions and intraband scattering of equilibrium electrons influenced by laser radiation, as indicated by the nonlinearity data. The considerably elevated refractive nonlinearity values in the analyzed film materials suggest their potential for practical application in optoelectronic devices.

The excess hydraulic pressure in water supply network pipes is one of the major problems in design and implementation stages of these projects. To reduce the excess pressure and maintain network safety, a variety of pressure reducing valves are used, which waste all the excess pressure. However, having used the appropriate water microturbines, while reducing the pressure loss to an optimum value, the system could recover the wasted energy. In this study, numerical simulation and experimental investigation of microturbine in a water supply system have been performed to evaluate the electrical power generation capacity of an over‐pressured network. The numerical simulation of the microturbine was conducted using Ansys‐Fluent software. The microturbine has been experimentally investigated with different inlet flow rates, the effect of different post‐microturbine heads and also the effect of different opening angles of guide plate on its performance, three different scenarios were defined. Based on numerical simulation and laboratory results, the best performance of the microturbine was obtained when the inlet flow rate was 0.01184 m ³ /s and also opening angle 20° for the guide plate, in which the microturbine output was equal to 59.01 W. The generated power by the microturbine can meet the electrical needs of sensors and other network monitoring equipment.

The wake characteristics behind a finned and a foam-wrapped circular cylinder has been compared in a study (Khashehchi et al 2014 Exp. Therm. Fluid Sci. 52 328–38) done by the Authors. In this paper, the shed vortices from the wake of the same cylinders have been studied. Shedding in a bluff body has an important effect on increasing the pressure drop downstream of the object. Here, we have used particle image velocimetry to investigate the detached vortices from the wake behind a foam-wrapped and a finned cylinder. The standard case of cross-flow over a bare cylinder, i.e. no surface extension, has also been tested as a benchmark. The experiments have been performed for Reynolds numbers 2000 based on the mean air velocity and the cylinder’s outer diameter. To identify the features of each aforementioned case, linear stochastic estimation has been applied to the velocity fields. Results show that unlike the fin, adding foam to the cylinder surface increases the size of detached vortices and amplifies the core strength. Moreover, foam-wrapped cylinder in contrast to the finned one produces strong three-dimensionality. Interestingly, finned cylinder’s results show less three-dimensionality compared to the bare cylinder.