Thermal–hydraulic modeling of water/Al2O3 nanofluid as the coolant in annular fuels for a typical VVER-1000 core

In this paper, a thermal–hydraulic analysis of nanofluid as the coolant is performed in a typical VVER-1000 reactor with internally and externally cooled annular fuel. The fuel assembly for annular case with 8 × 8 arrays is considered for annular pin configuration. The considered nanofluid is a mixture composed of water and particles of Al₂O₃ with various volume percentages. The fuel rod is modeled using a CFD code. To validate the calculated results, the present results of solid fuel with nanofluid and pure water are compared with other studies which have been done with visual FORTRAN language, DRAGON/DONJON code, COBRA-EN code and the mentioned analytical approaches have been validated by comparing with the final safety analysis report (FSAR). The comparison of the calculated results shows that the results are in good agreement with other studies. Thus, the accuracy of the validation is satisfactory. Moreover, the temperature distributions of the fuel, clad and coolant are described for water/Al₂O₃ nanofluid in solid fuel and annular fuel. It is observed that as the concentration of Al₂O₃ nanoparticles increases, due to higher heat transfer coefficient of Al₂O₃ nanofluid, the temperature of the coolant is increased and the central fuel temperature is reduced. Thus, it improves margin from peak fuel temperature to melting. Finally, it is illustrated the use of the annular fuel instead of solid fuel in core of the reactor, security and efficiency of the nuclear power plant will be increased.     

Combustion analysis of the diesel–biogas dual fuel direct injection diesel engine – the gas diesel engine

In this investigation, biogas (BG) was used as an alternative fuel in a single-cylinder, four-stroke, air-cooled, direct injection (DI) diesel engine that was operated on a dual fuel mode. Biogas was produced from a non-edible seed de-oiled cake-pongamia pinnata (Karanja), which was collected from the biodiesel industries. The BG was inducted along with the air in suction of the engine at four different flow rates varying from 0.3?kg/h to 1.2?kg/h in steps of 0.3?kg/h. The investigation results revealed that BG inducted at a flow rate of 0.9?kg/h gives better combustion characteristics of engine behaviour than those of other flows throughout the engine operation. The ignition delay (ID) and combustion duration of the engine run by dual fuel operation at a BG flow rate of 0.9?kg/h were found to be longer by about 2 °CA and 2.9 °CA, respectively, in comparison with diesel at full load. The cylinder peak pressure was found to be overall higher by about 11?bar than that of diesel at full load.     

Conductivity of Nafion 117 membrane used in polymer electrolyte fuel cells

The membrane electric transport (MC) directly influences the performance of the polymer electrolyte fuel cells (PEMFC). The membrane conductivity is determined by a number of parameters such as: hydration technique, graphite cell geometry and pressure applied when the membrane electrode assembly (MEA) is joined. In addition, the membrane conductivity might be influenced by the electrode position due to the possibility of anisotropic electric conductivity.     

Electricity generation with a sediment microbial fuel cell equipped with an air-cathode system using photobacterium

The main purpose of this study is the characteristic and nature of current generation with a pure culture of single cell in a sediment microbial fuel cell. A sediment microbial fuel cell with an air-cathode system was studied for a prolonged period of time. The current maintained a steady increase throughout the entire time period and reached to its peak of 1.82 μA with power density of 29,024.65 μW/cm² at day 35. Water parameters such as salinity and pH were observed throughout the entire time period for better understanding. Operation of water parameter had been done after stabilization of current output for every measurement. The electron transfer pathway was assessed by cyclic voltammetry study. A low current density was observed due to profound internal resistance (141 Ω), and the reason for which was ohmic losses. A linear relationship was observed between current density and power density. Phylogenetic analysis was performed with 16S rRNA to identify the studied organism.     

Synthesis and characterization of TiO2 nanoparticles by using new shape controllers and its application in dye sensitized solar cells

Nanoparticulated TiO₂ materials with anatase structure were synthesized by using two step hydrothermal method and using amine ligands as shape controllers. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron spectroscopy (TEM), scanning electron microscopy (SEM), and UV–vis spectroscopy. Dye-sensitized solar cells (DSSCs) employing these materials achieved conversion efficiencies as high as 2.61% for smallest nanoparticles that was resulted of an effective shape controller.     

Mass transfer and performance of membrane-less micro fuel cell: A review

Membrane-less micro fuel cells (MMFCs) are high potential alternative power sources compared to conventional batteries. They use the advantage of laminar flow without the presence of a membrane to separate the anode and the cathode. This article is a wide-ranging review of recent studies on mass transfer, performance, modelling advances and future opportunity in MMFCs research. The discussion focuses on the critical factors that limit the performance of MMFCs. Because MMFCs are diffusion-limited, most of this review focuses on design considerations to enhance the power density output. Moreover, the current status of computational modelling for MMFC systems to upgrade the cell performance will be presented. The review also identifies the challenges and opportunities available for increasing cell performance and making the MMFC a practical application device in the future.     

Optical and electronic property tailoring by MoS2-polymer hybrid solar cell

The ternary blend system such as binary donor and an acceptor or binary acceptor and a donor offers a way to improve the power conversion efficiency of the polymer solar cells (PSCs) by enhancing optical properties and electrical properties. In this work, PTB7, PC₇₁BM and Molybdenum disulfide nano-sheet (MoS₂NS) ternary blend system were investigated as an active material for OPV. The optimized ternary blend system showed increment of 17% power conversion efficiency (PCE) from 6.98% to 8.18%. The origin of improved PCE mainly arises from the significant increment in J_SC and marginal change in V_OC and FF. This improved PCE is due to increased light harvesting and improved charge carrier mobility in the active matrix. The marginal enhancement in V_OC and FF was correlated with the density of trap states (DOS) obtained from capacitance measurement of the device. The optical absorption and energy transfer mechanism of the ternary blend film is explained by absorption and photoluminescence measurement respectively. Further, the conversion efficiency due to improved charge carrier transport was described by modified SCLC mobility measurements for electron and hole only devices. The obtained result suggests that presence of MoS₂NS along with PTB7:PC₇₁BM binary system play dual role like an improved charge transport layer as well as light harvesting.     

Effect of SnO2 intermediate layer on performance of Ti/SnO2/MnO2 electrode during electrolytic-manganese process

SnO₂ intermediate layers were coated on the titanium (Ti) substrate by thermal decomposition. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that uniform SnO₂ intermediate layers with rutile crystal structure were successfully achieved. According to the results of linear sweep voltammetry (LSV), oxygen evolution potential (OEP) of the Ti/SnO₂/MnO₂ electrodes decreases with increasing SnO₂ content, indicating that the electro-catalytic oxidation activity of the electrode increases. Accelerated service life tests results demonstrate that SnO₂ intermediate layer can improve the service life of the Ti/SnO₂/MnO₂ electrode. As the content of SnO₂ intermediate layer increases, the cell voltage and the energy consumption decrease apparently.