Structure and Disorder in Squaraine–C60 Organic Solar Cells: A Theoretical Description of Molecular Packing and Electronic Coupling at the Donor–Acceptor Interface

Organic solar cells based on the combination of squaraine dyes (as electron donors) and fullerenes (as electron acceptors) have recently garnered much attention. Here, molecular dynamics simulations are carried out to investigate the evolution of a squaraine–C₆₀ bilayer interface as a function of the orientation and order of the underlying squaraine layer. Electronic couplings between the main electronic states involved in exciton dissociation and charge (polaron pair) recombination are derived for donor–acceptor complexes extracted from the simulations. The results of the combined molecular‐dynamics?quantum‐mechanics approach provide insight into how the degree of molecular order and the dynamics at the interface impact the key processes involved in the photovoltaic effect.     

Performance of Object Classification Using Zernike Moment

Moments have been used in all sorts of object classification systems based on image. There are lots of moments studied by many researchers in the area of object classification and one of the most preference moments is the Zernike moment. In this paper, the performance of object classification using the Zernike moment has been explored. The classifier based on neural networks has been used in this study. The results indicate the best performance in identifying the aggregate is at 91.4% with a ten orders of the Zernike moment. This encouraging result has shown that the Zernike moment is a suitable moment to be used as a feature of object classification systems.     

Carbonization behavior of oxidized viscose rayon fibers in the presence of boric acid–phosphoric acid impregnation

The oxidation and carbonization stages of viscose rayon fibers were performed in the presence of 3 % phosphoric acid and 4 % boric acid (PA–BA) impregnation. The results showed that PA–BA impregnation enhanced thermal stability and prevented the evolution of volatile by-products. During the oxidation stage carried out at 250 °C, the cellulose II crystalline structure was totally lost due to the decrystallization process. Carbonization was carried out in a pure nitrogen atmosphere at temperatures ranging from 600 to 1000 °C. The results obtained from the fiber thickness, linear density, carbon fiber yield, elemental analysis, volume density, X-ray diffraction, infrared (IR) and Raman spectroscopy, tensile testing, and electrical conductivity measurements showed that the carbonization temperature had a significant effect on the structure and properties of the resulting carbon fibers. Carbon fibers obtained from the oxidized viscose rayon fibers showed physical and chemical transformations with increasing carbonization temperature and were characterized by a reduction in fiber thickness and linear density values due to the removal of non-carbon elements together with increases in the carbon content, carbon to hydrogen ratio (C/H), volume density, tensile strength, tensile modulus, and electrical conductivity values. X-ray diffraction analysis showed that the interplanar d-spacing (d ₀₀₂) decreased, and that the apparent crystallite thickness (L _c) and the apparent crystallite width (L _a) increased with increasing temperature. IR spectroscopy in agreement with the elemental analysis showed the total loss of OH, CH, C=O, CH₂, C–O, and C–O–C groups arising from the completion of dehydration and dehydrogenation reactions indicating total elimination of the cellulose structure and the formation of amorphous carbon during high temperature treatment.     

Two-edge disjoint survivable network design problem with relays: a hybrid genetic algorithm and Lagrangian heuristic approach

This article presents a network design problem with relays considering the two-edge network connectivity. The problem arises in telecommunications and logistic networks where a constraint is imposed on the distance that a commodity can travel on a route without being processed by a relay, and the survivability of the network is critical in case of a component failure. The network design problem involves selecting two-edge disjoint paths between source and destination node pairs and determining the location of relays to minimize the network design cost. The formulated problem is solved by a hybrid approach of a genetic algorithm (GA) and a Lagrangian heuristic such that the GA searches for two-edge disjoint paths for each commodity, and the Lagrangian heuristic is used to determine relays on these paths. The performance of the proposed hybrid approach is compared to the previous approaches from the literature, with promising results.     

Characterization of BPN Pyrotechnic Composition Containing Micro‐ and Nanometer‐Sized Boron Particles

The effect of micro‐ and nanometer‐sized boron particles on boron‐potassium nitrate (BPN) ignition composition was investigated in this paper. As a starting point, thermochemical calculations were made to determine the most promising ignition compositions. Both stoichiometric and fuel‐rich formulations of BPN were produced to observe the performance variation due to boron content. Particle morphology of boron particles and the surface structure of the ignition compositions were investigated by SEM. The influence of micro‐ and nanometer‐sized boron particles on the calorific value, sensitivity properties, and pressure buildup of compositions were investigated. Sensitivity tests showed that all compositions were safe enough for handling. It was seen that although nanometer‐sized boron particles enhanced calorific value and pressurization rate, they did not have a contribution on the maximum pressure level. The maximum adiabatic flame temperature was attained by the stoichiometric composition, but in practice, the stoichiometric composition resulted in much lower performance than the fuel rich composition. Possible reasons for these behaviors of the compositions were discussed in the paper.     

Preparation and Characterization of hybrid graphene oxide composite and its application in paracetamol microbiosensor

Graphene oxides decorated with Sn(II) (Sn‐GO) were prepared via a redox reaction between graphene oxide (GO) and SnCl₂. GO was reacted Sn²⁺ leading to a homogeneous distribution of Sn on GO. An electrochemical sensor based on the electrocatalytic activity of functionalized graphene oxide for sensitive detection of paracetamol is presented. The electrochemical behaviors of paracetamol on grapheme modified carbon fiber electrodes were investigated by DC potential amperometry. The results showed that the Sn‐GO‐modified electrode exhibited excellent electrocatalytic activity to paracetamol. A redox process of paracetamol at the modified electrode was obtained. Such electrocatalytic behavior of graphene oxide is attributed to its unique physical and chemical properties, e.g., subtle electronic characteristics, attractive π–π interaction, and strong adsorptive capability. This electrochemical sensor shows an excellent performance for detecting paracetamol with a detection limit of 8 µM, a response time of 27 s, and a satisfied recovery. The sensor shows great promise for simple, sensitive, and quantitative detection and screening of paracetamol. We have investigated the composite properties of the self‐assembled electrodes for biological compounds analysis and showed that the Sn‐GO composite biosensor can achieve great sensitivity without significant bio material. The sensor shows great promise for simple, sensitive, and quantitative detection and screening of paracetamol. POLYM. COMPOS., 36:221–228, 2015. © 2014 Society of Plastics Engineers     

Corrosion inhibition studies of copper in highly concentrated NaCl solutions

The influence of the concentration of sodium succinate (SS) on the corrosion and spontaneous dissolution of copper in aerated non-stirred highly concentrated (5.0 M) NaCl solutions was studied at different temperatures (10–60 °C). The investigations involved weight loss as well as potentiodynamic polarization and impedance measurements. The inhibition efficiency increases with increase in the concentration of SS and decreases with temperature. The inhibition mechanism involves adsorption of SS on the copper surface. An adherent layer of inhibitor is postulated to account for the protective effect. Energy dispersion X-ray (EDX) examinations of the electrode surface confirmed the existence of such an adsorbed film. The potential of zero charge (pzc) of copper was studied by the ac impedance technique and the mechanism of adsorption is discussed.     

Applications of porous media combustion technology – A review

The rapid advances in technology and improved living standard of the society necessitate abundant use of fossil fuels which poses two major challenges to any nation. One is fast depletion of fossil fuel resources; the other is environmental pollution. The porous medium combustion (PMC) has proved to be one of the feasible options to tackle the aforesaid problems to a remarkable extent. PMC has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power dynamic range, the extension of the lean flammability limits, and the low emissions of pollutants. This article provides a comprehensive picture of the global scenario of applications of PMC so as to enable the researchers to decide the direction of further investigation. The works published so far in this area are reviewed, classified according to their objectives and presented in an organized manner with general conclusions.