Multidimensional and transient modeling of an alkaline water electrolysis cell

A three-dimensional (3-D) transient numerical model of an alkaline water electrolysis (AWE) cell with potassium hydroxide solution is developed by rigorously accounting for the hydrogen and oxygen evolution reactions and resulting species and charge transport through various AWE components. First, the AWE model is experimentally validated against a polarization curve corresponding to a wide range of currents as high as 2.0 A·cm^?2. In general, the simulation results compare well with the measured data and further reveal the operating characteristics of AWE cells, showing key distributions of solid/electrolyte potentials and multidimensional contours of reactant and product concentrations at various current densities. In particular, the contribution of hydroxide ion (OH^?) diffusion to the ohmic losses through porous electrodes and a porous separator are quantitatively examined at low and high electrolyte flow rates. The present full 3-D AWE model provides a basic understanding of the electrochemical and transport phenomena and can be further applied to practical large-scale AWE cell and stack geometries for grid-scale hydrogen production.     

Comparison of Performance of Packet Scheduling Algorithms in LTE-A HetNets

The concept of usage of heterogeneous networks (HetNets) is about improving the LTE system performance by increasing the capacity and coverage of the Macro cell. In this paper, a performance comparison of various packet scheduling algorithms such as Proportional Fair, Maximum Largest Weighted Delay First and Exponential/Proportional Fair is studied in detail in the HetNets environment. The key performance indicators such as throughput, packet loss ratio, delay and fairness are considered to judge the performance of the scheduling algorithms. Various strategies such as increasing the number of Pico cells in the cell edge were used in the simulation for the performance evaluation study. The results achieved through various simulations show that adding Pico cells to the existing Macros enhances the overall system performance in addition to the various scheduling algorithms implemented in Macros. For reader’s convenience, various types of graphs have been used to represent the simulation results to better understand the performance metrics of various scheduling algorithms. Simulation results shows that overall system gain has increased because of adding Picos and thereby providing better coverage in the cell edge areas and thereby increasing the capacity of the network to provide better quality of service.     

Friction factor correlation and pressure loss of single-phase flow inside herringbone microfin tubes

Pressure drop of single-phase turbulent flow inside herringbone microfin tubes of different fin dimensions has been measured experimentally to develop a general correlation of single-phase friction factor for the herringbone tubes. Water has been used as a working fluid and the mass flow rate has been varied from 0.03 to 0.2 kg/s, where the Reynolds number range is 10⁴ to 6.5 × 10⁴. Comparison of experimental data of the herringbone microfin tubes with those of helical microfin and smooth tubes shows that pressure drop of the herringbone tube is significantly higher than the helical and smooth tubes depending on the fin geometric parameters and mass velocity of the working fluid. Through semi-analytical approach and using the present experimental data, a new correlation of single-phase friction factor for the herringbone microfin tubes has been proposed incorporating the effects of fin geometric parameters. The proposed correlation can predict the experimental data within ±10%.     

Modulating response of Zea mays to induced salinity stress through application of nitrate mediated silver nanoparticles and indole acetic acid

Nanotechnology has been amplified in different areas of science as well as agriculture in the present era. So, the present work was designed to evaluate the result of nitrate mediated silver nanoparticles (Nit-AgNPs) and indole acetic acid (IAA) on physio-biochemical features of the selected maize variety (Pahari white) under 40 and 80 mM salinity induction. Seeds were propagated in triplicates in earthen pots (18 cm inferior and superior inside diameter, 20 cm stature, and 2 cm breadth) filled with silt and soil (1:2) having 3.09–5.12 Electrical conductivity (EC), 6.8–7.3 pH, and 4–16% moisture contents. Scanning electron microscopy results showed the average particle size around 90 nm indicating a high surface area suitable for adsorption properties, agglomerated, roughly spherical, and were uniformly dispersed. Elemental quantification of biosynthesized AgNPs analyzed via energy dispersive X-ray spectroscopy showed a strong peak at 3.0 KeV along with the presence of elements K, N, O, and C. Results of Thermo-gravimetric Analysis (TGA)/Differential Thermal Analysis (DTA) showed endothermic major decline at 150–300°C, while exothermic peak at 300–400°C. The growth responses at 40 mM salinity concentration have been reduced representing from the least boundary of chlorophyll “a,” “b,” and peroxidase content, whereas; this adverse effect has been reduced by operation of Nit-AgNPs as separate treatment and in combination with IAA. From the current study, it has been concluded that salinity concentration at 80 mM adversely affected the values of osmolytes, protein, and superoxide dismutase whereas the maximum amplitude of proline reduced by the application of Nit-AgNPs as distinct treatment indicating that the plant behaves normal with the combined application of nanoparticles and IAA.     

Mixing performance of a planar micromixer with circular obstructions in a curved microchannel

A numerical investigation of the mixing and fluid flow in a new design of passive micromixer employing several cylindrical obstructions within a curved microchannel is presented in this work. Mixing in the channels is analyzed using Navier–Stokes equations and the diffusion equation between two working fluids (water and ethanol) for Reynolds numbers from 0.1 to 60. The proposed micromixer shows far better mixing performance than a T-micromixer with circular obstructions and a simple curved micromixer. The effects of cross-sectional shape, height, and placement of the obstructions on mixing performance and the pressure drop of the proposed micromixer are evaluated.     

Assessment of environmental impacts of Sarda Sahayak Canal irrigation project of Uttar Pradesh,government, India

This paper analyses the results of studies conducted on the Sarda Sahayak Canal Irrigation Project of the U.P. Government, which was commissioned in 1974. The operation of this canal has created serious problems of environmental degradation in the command area. The problem of seepage started right from the beginning and at present it has created a situation which may be one of its type in the history of canal irrigation. The seepage in 1984 has damaged 385 villages, 13,677 houses and 2200 catties. Mature natural forests containing Sal trees have been killed by canal seepage over a vast tract. The canal seepage and high water table rendered vast tract waterlogged. Due to continuous waterlogging in the command area, the problems of Malaria, Filaria skin diseases and pest are very common. The canal is operating, and this report should help in assessing the environmental changes such as management of land, water and forests for sustainable development.     

Change in impedance of a single-turn coil due to a flaw in a conducting half space

The problem of detection and characterization of a flaw in a conducting half-space using an eddy-current coil oriented parallel to the interface is examined. An expression is derived for a first order approximation for the change in complex impedance due to a flaw located within the conducting medium. The overall impedance is a function of the radius and lift-off distance of the test coil and the conductivity of the material. An analytical expression is derived for the change in impedance as a function of the electric fields at the position of the flaw. It is found to be an integral over the volume of the flaw of the electric fields found with and without the flaw being present. The limiting case of a degenerate point flaw may be examined in greater detail by allowing the field in the presence of the flaw to be approximated by the unperturbed field. For flaws small enough that the field does not vary much over its volume, the field may be even further approximated by using just the value of the field at the position of the centroid of the flaw. Plots are shown to illustrate the behavior of the change in impedance as a function of the radial range of the flaw and the depth of the flaw centroid, using previously derived expressions for the fields for the unflawed case.