Coal liquefaction in lignin-derived liquids under low severity conditions

It is found that lignin-derived liquids when reacted with coal under mild reaction conditions (375 °C and 2.17 × 10⁶ − 3.55 × 10⁶ N m⁻¹) enhance the rate of coal depolymerization. Up to 30% enhancement in coal conversion rate is achieved using lignin-derived liquids. The influence of time of reaction and temperature on the degree of reaction was investigated. The lignin liquid-assisted coal depolymerization products (liquid) are observed to contain a significant amount of the desirable pentane-soluble fraction. Influence of the time of storage of lignin-derived liquids on coal conversion was also determined. Also reported are data on elemental analyses of the solid and liquid products. The liquid product analyses using n.m.r. and s.e.c. techniques are also presented. Based upon the experimental data collected, it is hypothesized that enhancement in coal depolymerization rate can be explained by a reaction pathway involving intermediates formed from lignin-derived lignin liquids. A mathematical model describing the reaction chemistry has been developed. Computed rate constants are also reported. The analysis indicates that the lignin-derived intermediates are short-lived as compared to the time needed for complete coal depolymerization.     

Thermophysical Properties of Binary Mixtures of Methanol with Chlorobenzene and Bromobenzene from 293 K to 313 K

Densities and viscosities have been measured for the binary mixtures of methanol with chlorobenzene and with bromobenzene from 293 K to 313 K over the complete composition range. Densities were used to compute the excess molar volume ( , for these binary systems. The results have been discussed in terms of molecular interactions. Furthermore, viscosity results were compared with a corresponding-states model. The average absolute deviation was found to be 1.9 %.     

Development of parthenium based activated carbon and its utilization for adsorptive removal of p-cresol from aqueous solution

The activated carbon was prepared from carbonaceous agriculture waste Parthenium hysterophorous by chemical activation using concentrated H2SO4 at 130+/-5 degrees C. The prepared activated carbon was characterized and was found as an effective adsorbent material. In order to test the efficacy of parthenium based activated carbon (PAC), batch experiments were performed to carryout the adsorption studies on PAC for the removal of highly toxic pollutant p-cresol from aqueous solution. The p-cresol adsorption studies were also carried out on commercial grade activated carbon (AC) to facilitate comparison between the adsorption capabilities of PAC and AC. For PAC and AC, the predictive capabilities of two types of kinetic models and six types of adsorption equilibrium isotherm models were examined. The effect of pH of solution, adsorbent dose and initial p-cresol concentration on adsorption behaviour was investigated, as well. The adsorption on PAC and on AC was found to follow pseudo-first order kinetics with rate constant 0.0016 min(-1) and 0.0050 min(-1), respectively. The highest adsorptive capacity of PAC and AC for p-cresol solution was attained at pH 6.0. Further, as an adsorbent PAC was found to be as good as AC for removal of p-cresol upto a concentration of 500 mg/l in aqueous solution. Freundlich, Redlich-Peterson, and Fritz-Schlunder models were found to be appropriate isotherm models for PAC while Toth, Radke-Prausnitz and Fritz-Schlunder were suitable models for AC to remove p-cresol from aqueous solution.     

RETRACTED ARTICLE: Sintered Aluminum–Graphene Nano-Bio Composite Materials for the Medical Application

Powder Metallurgy and Metal Ceramics - It is known that graphene is stronger than steel. It is characterized by extremely high values of the Young's modulus (up to 1 TPa), strength (~125 GPa)...     

Shear waves in a piezoceramic layered structure

The propagation of SH-type wave is studied in a composite structure consisting of alternating polymeric layers and porous piezoelectric layers. The porous piezoelectric materials of the composite structure are assumed to have 6mm symmetry and their poling direction is along z-axis. Layers of the polymer are considered as isotropic dielectric elastic material. Solutions of the field equations for the porous piezoelectric material and for the polymeric material are obtained. Two cases, first when the direction of propagation of the SH-type wave is taken along the direction normal to the layering of the composite structure, and second when the propagation direction is taken along the layering, are considered for the derivation of the phase velocity. The dispersion and the stop-pass band behavior of the Floquet wave is also discussed. Numerical results for phase velocity and stop band effect are presented for a periodic system of alternating PZT-5H and polythene layers. The influence of volume fraction on phase velocity and stop band effect is discussed.     

Structural and optoelectronic characterization of prepared and Sb doped ZnO nanoparticles

This paper briefly reports the structural and optoelectronics properties of prepared pure and Sb doped ZnO nanoparticles. Doping with suitable elements offers an efficient method to control and enhance the optical properties of ZnO nanoparticles, which is essential for various optoelectronics applications. Sb doped ZnO nanoparticles have significant concern due to their unique and unusual electrical and optical properties. In the present work, we report the synthesis of Sb doped ZnO successfully with average particle size range from 26 to 29 nm via direct precipitation method. The phase purity and crystallite size of synthesized ZnO and Sb doped nano-sized particles were characterized and examined via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The elemental analyses of undoped and doped ZnO nanoparticles were examined by using energy-dispersive X-ray spectroscopy (EDAX).We investigated and measured the optoelectronics properties of synthesized ZnO and Sb doped ZnO nanoparticles by employing photoluminescence and UV–Visible spectroscopy. The influence of Sb doping on photoluminescence (PL) spectra of ZnO nanoparticles, which consists of UV emission and broad visible emission band, is found to be strongly dependent upon the Sb concentration for all the Sb doped ZnO nanoparticles samples under investigation. The UV–Visible absorption study shows an increase in band gap energy as Sb is incorporated on the ZnO nanoparticles.     

Optimal Homotopy-Based Approximate Solutions for Process Systems Represented by the Axial Dispersion Model

An efficient variant of the homotopy analysis method, namely the optimal homotopy analysis method (OHAM), has been presented for the solution of chemical process systems that are represented by the axial dispersion model. To show its efficiency OHAM has been successfully applied to one of the popular chemical engineering systems, i.e., axial dispersion model of a tubular chemical reactor sustaining nonlinear kinetics. The obtained optimal homotopy results have been shown to agree closely with the numerically obtained results. The usefulness of OHAM has further been illustrated by effectively capturing multiple solutions, which frequently arise in non-monotonic kinetics. Convergence of the so-obtained OHAM results has also been discussed. It is also worthwhile to mention that the presented methodology of OHAM, with slight modification, can easily be extended to other engineering systems not represented by the axial dispersion model.     

Hybrid Multi-FPGA Board Evaluation by Permitting Limited Multi-Hop Routing

Multi-FPGA Boards (MFBs) have been in use for more than a decade for implementing systems requiring high performance and for emulation/prototyping of multimillion gate chips. It is important to develop an MFB architecture which can be used for emulation or prototyping of a large number of circuits. A key feature of an MFB is its routing architecture defined by its inter-Field-Programmable Gate Array (FPGA) connections. There are two types of inter-FPGA connections, namely–fixed connections (FCs) connecting a pair of FPGAs through dedicated wires and programmable connections (PCs) which connect a pair of FPGAs through a programmable switch. An architecture which has a mix of both these type of connections is called a hybrid routing architecture. It has been shown in the literature [7] that a hybrid MFB architecture is more efficient for emulation than an architecture with only one type of connections. The cost of an MFB and delay of the emulated circuit on it depends on the number of PCs used for emulation. An objective of a designer of an MFB for circuit emulation is to minimize the required number of PCs. In this paper, we describe algorithms to evaluate the requirement of PCs for many hybrid routing architectures.The requirement of PCs can be reduced if some programmable connections are replaced by a connection using only FCs by routing through FPGAs. Such a routing is called multi-hop routing. We present an optimal and a heuristic algorithm for estimation of PCs when limited number of hops through FPGAs are permitted. The unique feature of our evaluation scheme is that it is generic and treat routing architecture as a parameter. We have used benchmark circuits as well as synthetic cloned circuits for testing our algorithms. Our heuristic algorithm is very fast and gives optimal results most of the time. Our algorithms can be used for actual routing during circuit emulation.