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By using a multispecies fluid model, the tunability and controllability of plasma parameters such as distributions of electron density, electron energy, ion density, and electric field in a microdielectric barrier discharge (DBD) with a charge injector electrode and driven by negatively polarized nanosecond pulsed voltage superimposed on a positive DC bias voltage are investigated. To this end, the effects of changing features of pulsed voltage like pulse rise time (10-20 ns), pulse peak width (10-15 ns), and pulse fall time (20-30 ns) on characteristics of argon plasma formed inside the reactor are studied. The results show that with the increase in pulse width and pulse rise time, the density of electron and ion increases, while fall time change does not significantly affect the plasma parameters. Generally, the results of this study explicitly prove the possibility of controlling plasma formed inside DBD reactors driven by negative pulse voltage combined with a positive DC voltage, which is very important in waste gas conversion applications.

In the present article, the thermodynamic potential of a sustainable plasma-assisted nitrogen fixation process for co-production of ammonia and hydrogen is investigated. The developed process takes advantage of chemical looping system by using a liquid metal such as gallium to drive nitrogen fixation reaction using three reactors including reactor R1 to produce gallium nitride from gallium and nitrogen, reactor R2 to produce ammonia and hydrogen from gallium nitride, and plasma reactor R3 to convert gallium oxide to pure gallium. The results of the thermodynamic assessments showed that the proposed reactions are spontaneous and feasible to occur in the reactors. Likewise, the first two reactions are exothermic with ΔH=-230[Formula presented] and ΔH=-239[Formula presented] in the reactors R1 and R2, respectively with an equilibrium chemical conversion of 100%. The plasma reactor requires thermal energy to drive an endothermic reaction of gallium oxide dissociation withΔH=+870[Formula presented]. Thermochemical equilibrium analysis showed that the molar ratio of steam to GaN, as well as the operating pressure and temperature of reactor R2 are the main operating parameters identifying the product composition in the reactor such that by increasing the temperature, the molar ratio of hydrogen to ammonia increases. However, by increasing the molar ratio of steam/GaN (φ value) from 0.1 to 1, the hydrogen content of the reactor increases from 45% to 70% at 400 °C. For φ > 1.0, the hydrogen content decreases while more hydrogen participate in the formation of NH3 thereby increasing the mole fraction of ammonia in the reactor. The equilibrium chemical conversion of all three reactors is expected to reach the completion point (χ = 100%) due to the highly negative Gibbs free energy of the liquid metal-based reactions together with a large thermal driving force supported by thermal plasma reactor. Finally, a scalability study points at a possible use of the new disruptive process design at small scale, and possible industrial transformation scenarios for a distributed production at a local site of consumption are depicted.

Film deposition onto nanoparticles by low-pressure plasma in the presence of an external electric field is studied numerically. The plasma discharge fluid model along with surface deposition and heating models for nanoparticles, as well as a dynamics model considering the motion of nanoparticles, are employed for this study. The results of the simulation show that applying external field during the process increases the uniformity of the film deposited onto nanoparticles and leads to that nanoparticles grow in a spherical shape. Increase in film uniformity and particles sphericity is related to particle dynamics that is controlled by parameters of the external field like frequency and amplitude. The results of this work can be helpful to produce spherical core-shell nanoparticles in nanomaterial industry.

Ferromagnetic single electron transistor with electrodes having different temperatures is investigated and the effects of changing electrodes temperature on TMR of system are studied. A modified orthodox theory is used to study the system and to calculate the electron tunneling transition rate. The results show that the temperature of electrodes can be an effective tool to control and tune the tunnel magnetoresistance of FM-SET. Also, the effects of parameters such as resistance ratio of junctions, magnetic polarization and spin relaxation time on the behaviour of the system are studied.

The uniformity of film deposition on charged nanoparticles, trapped near the sheath of a capacitively coupled plasma reactor, is studied by numerical simulation of the multi-fluid plasma equations, surface deposition processes, and nanoparticle heating effects. It is found that the anisotropy in the ion flux onto the powered electrode may be hold responsible for the film nonuniformity. The nonuniformity increases with increasing of the particle radius, although small particles lose sphericity faster than the large particles. Because of the electron temperature dependence of the deposition rate and the incident ion flux, higher electron temperatures lead to more nonuniform film deposition. However, the uniformity is improved and the sphericity is restored by the increase in the background gas pressure and/or temperature.

Background & Aim: Physical activity has an important role in the length of life of hemodialysis patients. Some complementary interventions such as relaxation technique might be effective on the level of physical activity. The aim of this study was to evaluate the effects of Benson’s relaxation technique on physical activity of hemodialysis patients. Material & Methods: It was a randomized controlled trial that was carried out in the hemodialysis units of Shiraz University of Medical sciences. Eighty six hemodialysis patients were randomly assigned to Benson’s relaxation technique group (n =43) and control group (n=43). The technique was performed in experimenmtal group for 20 min, twice a day for 8 consecutive weeks. Physical activity was assessed by the "Daily Living Activity (ADL)" and "Instrumental Daily Living Activity (IADL)" scale in both groups at baseline and 8 weeks after intervention. Data were analyzed with independent and dependent samples t–test, and chi–square using SPSS-PC (v.16). Results: Before the intervention, the mean score of ADL in intervention and control groups was 12.53 (2.54) and 12.30 (2.78), respectively. However, at the 8th week of the intervention, the mean score of ADL in the intervention group was 13.42 (1.44) and in the control was 11.74 (3.45). The results of independent samples t–test showed a significant difference between ADL of the groups (t=2.83, P=0.006). In addition, the mean score of IADL at the beginning of study in intervention and control group was 14.36 (4.36) and 12.04 (6.01) and at 8th week of intervention, it was 15.62 (3.77) and 12.00 (5.77), respectively. A significant difference was observed between two groups regarding the IADL scale at the 8th week of the intervention (t=3.29, P=0.001). Conclusion: The findings suggest beneficial effects of Benson’s relaxation technique on the improvement of physical activity in hemodialysis patients. Therefore, teaching relaxation techniques could serve as a resource for improving the levels of physical activity.

The magneto-optical responses of a one-dimensional photonic crystal containing two magnetized plasma defect layers with operation in the millimeter wavelength region are studied by using a 4 × 4 transfer matrix method and full wave numerical simulation. The results of this study show that not only the values of the magneto-optical effects such as Kerr and Faraday rotations are tunable by the magnetic field and plasma layer parameters but also the positions of resonant modes in the frequency region are adjustable by these parameters. Also, it is found out that the repetition numbers of middle and surrounding unit cells in the structure can be considered to be other key factors for tuning the characteristics of resonant modes and magneto-optical responses related to them.

A self-consistent model is used to study the surface coating of a collection of charged nanoparticles trapped in the sheath region of a low pressure plasma reactor. The model consists of multi-fluid plasma sheath module, including nanoparticle dynamics, as well as the surface deposition and particle heating modules. The simulation results show that the mean particle radius increases with time and the nanoparticle size distribution is broadened. The mean radius is a linear function of time, while the variance exhibits a quadratic dependence. The broadening in size distribution is attributed to the spatial inhomogeneity of the deposition rate which in turn depends on the plasma inhomogeneity. The spatial inhomogeneity of the ions has strong impact on the broadening of the size distribution, as the ions contribute both in the nanoparticle charging and in direct film deposition. The distribution width also increases with increasing of the pressure, gas temperature, and the ambient temperature gradient.

A self-consistent combination of plasma fluid model, nanoparticle heating model, and surface deposition model is used to investigate the coating of nanosize particles by amorphous carbon layers in a low pressure plasma reactor. The numerical results show that, owing to the net heat release in the surface reactions, the particle temperature increases and its equilibrium value remains always 50 K above the background gas temperature. The deposition rate decreases with increasing of the particle temperature and the corresponding time scale is of the order of 10 ms. The deposition rate is also strongly affected by the change in plasma parameters. When the electron temperature is increased, the deposition rate first increases due to the enhanced ion and radical generation, shows a maximum and then declines as the particle temperature rises above the gas temperature. An enhancement in the background gas pressure and/or temperature leads to a reduction in the deposition rate, which can be explained in terms of the enhanced etching by atomic hydrogen and particle heating by the background gas.

As an emerging technology that features the integration of microfluidics and non-equilibrium plasmas, microfluidic plasmas not only allow the precise and effective matter and heat transport via the microfluidic system, but also provide an extremely reactive medium full of high energy plasma-generated species. Therefore, they could open new pathways for chemical synthesis or chemical engineering processes that are hardly achievable by conventional methods. In this review, three main microfluidic plasma configurations are reviewed, including plasmas confined within microchannels, plasma jets beyond microchannels and microfluidic plasma arrays. The state-of-the-art diagnostic techniques for characterizing the microfluidic plasma are also examined. A broad range of applications of microfluidic plasmas of particular interest to chemistry and chemical engineering, such as nanomaterials fabrication, surface modification, chemical synthesis, environmental application, and micro total analysis systems, are discussed. The research gaps, bottlenecks and future perspectives of this novel technology are presented.