The plastic-crystalline phase of succinonitrile as a universal matrix for solid-state ionic conductors

Solid ionic conductors are actively sought for their potential application in electrochemical devices, particularly lithium batteries. We have found high ionic conductivity for a large variety of salts dissolved in the highly polar medium based on the plastic-crystal form of succinonitrile (N[triple bond]C[bond]CH(2)[bond]CH(2)[bond]C[triple bond]N). Its high diffusivity, plasticity and solvating power allowed the preparation of a large number of materials with high ionic conductivity, reaching values of 3 mS cm(-1) at 25 degrees C (two orders of magnitude above polymers). Their ease of preparation and processing allowed us to study the influence of the solute on ionic conduction within this medium. Comparisons revealed a dichotomy between plastic crystals and conventional polymer media. The usefulness of these new, easily processed electrolytes was asserted in electrochemical tests with lithium intercalation electrodes.     

Synthesis of artificial neural networks by transconductors only

Hardware implementation of artificial neural networks has been attracting great attention recently. In this work, the analog VLSI implementation of artificial neural networks by using only transconductors is presented. The signal flow graph approach is used in synthesis. The neural flow graph is defined. Synthesis of various neural network configurations by means of neural flow graph is described. The approach presented in this work is technology independent. This approach can be applied to new neural network topologies to be proposed or used with transconductors designed in future technologies.     

Carbon nanotubes: properties,synthesis, purification,and medical applications

Current discoveries of different forms of carbon nanostructures have motivated research on their applications in various fields. They hold promise for applications in medicine, gene, and drug delivery areas. Many different production methods for carbon nanotubes (CNTs) have been introduced; functionalization, filling, doping, and chemical modification have been achieved, and characterization, separation, and manipulation of individual CNTs are now possible. Parameters such as structure, surface area, surface charge, size distribution, surface chemistry, and agglomeration state as well as purity of the samples have considerable impact on the reactivity of carbon nanotubes. Otherwise, the strength and flexibility of carbon nanotubes make them of potential use in controlling other nanoscale structures, which suggests they will have a significant role in nanotechnology engineering.     

Capillary phenomena and disintegration processes of a square cylindrical liquid column

A numerical study has been performed to investigate some general features of the time-dependent dynamics of a square cylindrical liquid column during its relaxation and disintegration processes. A computer code based on VOF method has been developed to reveal the insight phenomena of the processes. Before using for present investigation, the code is validated by comparing the simulation result with the experimental data. It is found that the simulation result agrees well with the experiment and decided to use this code for the investigation of relaxation, disintegration and capillary instability of the liquid column. In present investigation the numeric illustrates the underlying physics during relaxation of the liquid cylinder, formation of capillary wave, its propagation and disintegration of liquid column. The investigation on the disintegration processes shows some significant differences from those predicted by conventional jet atomization theories. It can be observed that the formation of capillary wave is initiated by the surface tension on the sharp edge of the square end of the cylinder and the propagation of the wave occurs due to the effect of surface tension force on the motion of the fluid. The investigation reveals that before disintegration of the liquid, the capillary waves become unstable and the source of this instability is inherently developed by the system.     

Predictive control of drying process using an adaptive neuro-fuzzy and partial least squares approach

In this paper, adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN), and partial least squares (PLS) approaches are applied to predictive control of a drying process. In the proposed approaches, the PLS analysis is used to pre-process actual data and to provide the necessary background to apply ANN and ANFIS approaches. A reasonable section of this study is assigned to the modeling with the aim at predicting the granule particle size and executing by ANFIS and ANN. ANN holds the promise of being capable of producing non-linear models, being able to work under noise conditions, and being fault tolerant to the loss of neurons or connections. Also, the ANFIS approach combines the advantages of fuzzy system and artificial neural network to design architecture and is capable of dealing with both limitation and complexity in the data set. The efficiencies of ANFIS and ANN approaches in prediction are compared and the superior approach is selected. Finally, by deploying the preferred approach, several scenarios are presented to be used in predictive control of spray drying as an accurate, fast running, and inexpensive tool. This is the first study that presents a flexible intelligent approach for predictive control of drying process by ANN, ANFIS, and PLS. The approach of this study may be easily applied to other production process.     

Effect of polyethylenimine addition and washing on stability and electrophoretic deposition of Co3O4 nanoparticles

In this work, the parameters of cobalt oxide suspension such as conductivity, zeta potential, particle size, stability, and finally the electrophoretic behavior of particles in the absence and presence of polyethylenimine (PEI) in acetone medium were investigated. Also, the effects of washing on the stability and electrophoretic deposition of Co₃O₄ were studied. Characterization of the obtained layer by optical microscopy revealed that there was no deposition in the suspension without PEI, while a uniform layer was formed in the presence of PEI additive. Scanning electron microscopy (SEM) results confirmed the uniformity of layer obtained in acetone using PEI additive. Moreover, SEM results demonstrated that more porous microstructures were obtained at longer deposition durations. The difference in the porosity of the layers, as indicated by the SEM micrographs, is attributed to increase in the deposition time.     

One-pot two-step lipase-catalyzed synthesis of α,ω-thiophene-capped poly(ε-caprolactone) macromonomers and their use in electropolymerization

Macromonomers based on poly(ε-caprolactone) (PCL) with α,ω-thiophene functional end groups were prepared in bulk by enzymatic polymerization using immobilized Candida Antarctica lipase B (Novozym 435) as the catalyst. In the synthesis strategy, 3-thiophenemethanol was used to initiate the enzyme-assisted ring-opening polymerization of ε-caprolactone (ε-CL) to yield PCL with α-thiophene end group (initiation reaction, ThPCL) and then 3-thiopheneacetic acid was added to prepolymerized ε-CL to introduce ω-thiophene functionality in termination step (ThPCLTh). Macromonomers were characterized by ¹H and ¹³C NMR, FTIR, and GPC. Moreover, the obtained macromonomers were employed in electropolymerization experiments and copolymers with thiophene or pyrrole were synthesized through their end thiophene groups. These polymers were characterized by cyclic voltammetry (CV), FTIR, and scanning electron microscopy (SEM). Conductivity measurements were carried out by the four-probe technique.     

Effect of CO<Subscript>2</Subscript> concentration on the performance of different thermodynamic models for prediction of CH<Subscript>4</Subscript>+CO<Subscript>2</Subscript>+H<Subscript>2</Subscript>O hydrate equilibrium conditions

Accurate prediction of phase equilibria regarding CH₄ replacement in hydrate phase with high pressure CO₂ is an important issue in modern reservoir engineering. In this work we investigate the possibility of establishing a thermodynamic framework for predicting the hydrate equilibrium conditions for evaluation of CO₂ injection scenarios. Different combinations of equations of state and mixing rules are applied and the most accurate thermodynamic models at different CO₂ concentration ranges are proposed.     

Removal of melanoidin from molasses spent wash using fly ash-clay adsorbents

Removal of melanoidin pigment from molasses spent wash was investigated using a new adsorbent. Solid adsorbents were fabricated from charcoal fly ash and clay. The effect of various molasses concentration (6 to 12 g/l) on removal efficiency was studied. The obtained results revealed that maximum removal efficiency of 82% was achieved at the molasses concentration of 6 g/l and contact time of 7 h. The saturated porous adsorbents were regenerated and reused to conduct similar experiments. The achieved data showed that more than 90% of the capacity of the fresh adsorbent was recovered after regeneration. Various adsorption isotherms of Langmuir, Freundlich, Temkin and Harkins-Jura were applied to interpret the obtained experimental data. The obtained results revealed that the sorption data were well described by the Harkins-Jura model. Also, various kinetic models of pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion were used to predict the characteristic parameters which are useful in process design. It was concluded that the best fit was obtained with pseudo-second order kinetic model at low molasses concentrations.