Metasurface based pattern reconfigurable antenna for 2.45 GHz ISM band applications

In this article, a Z‐shaped antenna is designed for 2.45 GHz ISM band applications. The proposed antenna is surrounded by metasurface‐based unit cells. The unit cells are designed to reflect for the proposed frequency. Each of this unit cells are activated with the help of a diode. Unit cell is considered active by switching on the diode of respective unit cell. According to the activation of unit cell the pattern of the antenna will be reconfigured. The 2.45 GHz ISM band pattern reconfigurable microstrip antenna is presented. The radiation pattern of the antenna can be steered toward a desired direction by activating appropriate metasurface unit cell, minimizing the interference and optimizing medium usage. The proposed antenna performance is presented with the help of reflection coefficient and the pattern steerable capability by activating metasurface unit cells. The proposed antenna is having azimuth‐pattern reconfigurable capability around 360°.     

Ternary Blends of Renewable Fast Pyrolysis Bio-Oil,Advanced Bioethanol,and Marine Gasoil as Potential Marine Biofuel

An alternative for reducing emissions from marine fuel is to blend bio-oil from lignocellulose non-edible feedstocks to diesel fossil fuels. Phase diagrams of the ternary systems were built to represent the transition from heterogeneous regions to homogeneous regions. Four homogeneous blends of bio-oil of eucalyptus-bioethanol-marine gasoil were experimentally characterized with respect to the most important fuel parameters for marine engines: water content, flash point, low heating value, viscosity, and acidity. Blends with closer properties to marine gasoil replacement, lower costs, and environmental impacts should be tested for large engines.     

Methanol and proton transport through chitosan-phosphotungstic acid membranes for direct methanol fuel cell

Composite chitosan-phosphotungstic acid membranes were synthesized by ionotropic gelation. Their liquid uptake is higher for thin membranes (23 ± 2 μm), while it is lower (~70%) for thicker membranes (50-70 μm). Polarization curves recorded using single module fuel cell at 70°C allowed to estimate a peak power density of 60 mW cm⁻² by using 1 M as methanol and low Pt and Pt/Ru loadings (0.5 and 3 mg cm⁻²) at the cathode and at the anode, respectively. Electrochemical impedance spectroscopy was used to estimate the membrane conductivity and to model the electrochemical behavior of methanol electrooxidation inside the fuel cell revealing a two-step mechanism mainly responsible of overall kinetic losses. Transport of methanol inside the membrane was studied by potentiostatic measurements, allowing to estimate a methanol diffusivity of 3.6 × 10⁻⁶ cm² s⁻¹.     

Moving pentagons on nanocones

Abstract

Fullerenes are made by the intersection of twelve pentagonal nanocones. This note deals with an innovative isomeric mechanism, based on a sequence of Stone-Wales rotations, for moving the pentagonal face on the cusp of the nanocone. The modified nanocone is the seed for creating new fullerenes with different symmetry and size. Present results may help to model fullerene formation and, on the pure algorithmic side, may contribute to evolve the computer tools that generate fullerenes. This mechanism may also find application in mimicking the behaviors of biological systems that, like many viruses, are also describable in terms of spherical cages tiled by polygons.