Matrix solution to electromagnetic scattering by a conducting cylinder with an eccentric metamaterial coating

Closed series solution to scattering by an eccentric coated cylinder is realized in matrix form. Diffracted radiation characteristics are investigated for N incident plane transverse electric (TE) waves. The solution is obtained by the boundary value analysis and the addition theorem of the Bessel's functions. Wave transformation and orthogonality of the complex exponentials are also used to find an infinite series in the solution. Numerical results are shown by reducing the infinite series to a limited number of terms and compared to previously published works.     

A Kinetic Theory approach for laser pulse heating process

Pulsed lasers are being widely used in industry for their high precision and low cost in material processing. In order to understand the laser machining mechanism, a thermal analysis of the process is of utmost importance. In the present study, heat transfer mechanisms relevant to pulsed laser heating is solved numerically using the Kinetic Theory approach for different types of laser pulses. A comparison between the temperature profiles developed due to different pulses is also carried out. In the heat transfer model, conduction and convection due to melting and evaporation are considered. The laser pulse profiles introduced in the analysis are selected as appropriate to laser machining processes. Stainless steel is selected as the heat transfer medium.     

Harmonic and intermodulation performance of active integrated-optic waveguides

An empirical formula is developed for the static input/output optical characteristic of the active integrated-optic waveguide. Using this formula, closed-form analytical expressions, in terms of the ordinary Bessel functions, are obtained for the output optical components resulting from a modulated multisinusoidal optical input. Using these expressions the effect of the wavelength of the light input, the guide width, the modulation depth and the optical power for transperancy on the harmonic and intermodulation performance of the active integrated-optic waveguide can be studied.     

Self-adaptive methods for mixed quasi-variational inequalities

It is well known that the variational inequalities involving the nonlinear term φ are equivalent to the fixed-point problems and the resolvent equations. In this paper, we use these alternative equivalent formulations to suggest and analyze some new self-adaptive iterative methods for solving mixed quasi-variational inequalities. Our results can be viewed as significant extensions of the previously known results for mixed quasi-variational inequalities. An example is given to illustrate the efficiency of the proposed method.     

Coagulation-crossflow microfiltration of domestic wastewater

The effect of using alum, polyaluminum silicate sulfate (PASS), and lime as coagulants on the performance of crossflow microfiltration of domestic wastewater was investigated. The primary membrane used throughout the study was made of woven polyester, while the dynamic membrane was formed by circulating MnO₂ precipitate. Slug doses of the coagulants were added to the circulation tank of the experimental setup at the beginning of each run. Doses of 20 to 120 mg/l of alum were investigated at pH of 7. The results showed an improvement in flux values with the increase in alum dose until an optimum dose beyond which no significant improvement was seen. Flux improvement was attributed to the agglomeration of particles which can be easily swept away by the shearing actions created by the crossflow velocity. Permeate quality was not found to be significantly affected by the increase in alum dose. PASS, which is an aluminum salt, was seen to behave in the same manner as alum when used as a coagulant. Lime was not found to be a suitable coagulant under these conditions.     

Antiviral phytochemicals identification from Azadirachta indica leaves against HCV NS3 protease: an in silico approach

Hepatitis C virus (HCV) is a major health problem across the world affecting the people of all age groups. It is the main cause of hepatitis and at chronic stage causes liver cirrhosis and hepatocellular carcinoma. Various therapeutics are made against HCV but still there is a need to find out potential therapeutics to combat the virus. The goal of this study is to identify the phytochemicals of Azadirachta indica leaves having antiviral activity against HCV NS3 protease through molecular docking and simulation approach. Results show that the compound 3-Deacetyl-3-cinnamoyl-azadirachtin possesses good binding properties with HCV NS3/4A protease. It can be concluded from this study that Deacetyl-3-cinnamoyl-azadirachtin may serve as a potential inhibitor against NS3/4A protease.     

Some aromatic polyimides based on diamines containing hydrazo group and ether linkages

Three new hydrazo-bridged diamines, 4,4′-bis [4-(4-aminophenyloxy) phenylhydrazyl] biphenyl (BPD-2), 4,4′-bis [4-(4-aminophenyloxy) phenylhydrazyl] biphenyl ether (SPD-2) and 4,4-bis [4-(4-aminophenyloxy) phenyl] hydrazine (APD-2), were synthesized by the reduction of three azo-diols, 4,4′-bis (4-azo-1-hydroxyphenyl) biphenyl (BPD), 4,4′-bis (4-azo-1-hydroxyphenyl) biphenyl ether (SPD) and azo-4-hydroxybenzene (APD), and polymerized with pyromellitic dianhydride (PM), 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BP) and 3,4,9,10-perylenetetracarboxylic acid dianhydride (PR) either by one-step solution polymerization or by two-step procedure which includes ring-opening polyaddition to give poly(amic acid) followed by cyclic dehydration to polyimide. The monomers and polyimides were characterized by their elemental analyses, FTIR and ¹H NMR spectroscopy. Glass transition temperatures of the polymers are quite high (175-310 °C), characteristic of polyimides. The decomposition temperatures for 10% weight loss fall in the range of 280-575 °C in nitrogen. Activation energies of pyrolysis for each of the polymers calculated from Horowitz and Metzger's method are also high (52.54-95.28 kJ mol⁻¹). The inherent viscosities of the polyimides at a concentration of 0.5 g/dl in DMF range from 0.94 to 1.93 dl/g.     

Miscibility studies of PVC/Aramid blends

Blends containing PVC and aramid (Ar) matrices were probed for their miscibility. In this respect, Ar chains were synthesized by aromatic diamine and diacid chloride in amide solvent. The Ar thus synthesized was characterized through Fourier transform infrared (FTIR) spectroscopy and molecular weight determination. Blend system Ar/PVC was investigated over a range of Ar/PVC ratios. Their mechanical profiles in terms of maximum stress, maximum strain, toughness, and initial moduli have been explored. Thermal properties and morphology of the blends were estimated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). A good correlation was observed between thermal, mechanical, and morphological properties of the blends. The presence of hydrogen bonding among polymers was evaluated through FTIR spectroscopy, which is believed to be responsible for the blend miscibility. Optimal thermal and mechanical profiles were depicted by the blend containing 40-wt% PVC in the Ar matrix.