CATALYTIC CRACKING OF TARS FROM COAL DEVOLATILIZATION

ABSTRACT

A set of runs were performed on the catalytic and thermal cracking of the tars present fn the gasifier off-gas stream; the cracking referred to here Js essentially hydrocracking, in view of the considerable amount of hydrogen being present in the gas stream. The catalyst evaluated for tar cracking was a commercial cobalt-molybdenum catalyst, suppported on γ-Al₂O₃(Katalco-477). It was observed that there was a decrease in the amount of tar obtained with the cracking unit on-line with the gasifier; the tars were cracked to gaseous products in the presence of catalyst. Furthermore, it appeared that higher ring structures were transformed to less heavier components; thus cracking could become beneficial in downstream processing of the gas stream coming out of a gasifier.     

Thermal characterisation study of ZrO2/water nanofluid

ABSTRACT

Nanofluids act as tough elements in future of coolants in thermal management systems. Nanofluids have a remarkable potential in the process of heat transfer augmentation, which is reported in various investigations conducted by researchers across the world. Nanofluids attracted many researchers and the progress in this field has been tremendous because of the high thermal properties and probable applications in some areas like aerospace, transportation industry, medical regions and also as micro electronics. These fluids are having conjoined properties of base fluid and nano particles. This current work reports the thermophysical properties of ZrO₂/water-based nanofluid. The synthesised nanoparticles have been characterised by scanning electron microscope and XRD techniques. The behaviour of thermal conductivity and viscosity of the ZrO₂/water-based nanofluid of various concentrations have been studied.     

Growth studies of Azolla pinnata RBr. in a permanent pond

The growth pattern of Azolla pinnata in association with Spirodela polyrhiza was studied in a permanent pond. These two plants would provide a regular source of biomass. The suitability of integration of Azolla pinnata into other aquatic plants ‐ based wastewater treatment systems has been proposed. The favourable qualities offered by Azolla pinnata as a component in wastewater treatment systems has been emphasized.     

The Potentials and Pitfalls of ‘Art in Research’ Methodologies: Foregrounding Memory and Emotion in Planning Research

ABSTRACT

The article draws on a two-month project with forty-four high school students in Reston, Virginia to suggest that ‘art in research’ methodologies might be useful to shift away from the problematic histories of planning as solely a technical endeavor based in masculinist conceptions of legitimate research. I propose that we can radically reimagine planning research and practice as an emancipatory endeavor for its participants, suggesting that the iterative and longer art-making process may usefully complement traditional qualitative planning research, specifically helping to uncover relevant memories and emotions of participants.     

Optimization of Welding Process Parameters for 9Cr-1Mo Steel Using RSM and GA

Optimization of A-TIG welding process parameters for 9Cr-1Mo steel has been carried out using response surface methodology (RSM) and genetic algorithm (GA). RSM has been used to obtain the design matrix for generating data on the influence of process parameters on the response variables. A second-order response surface model was developed for predicting the response for the set of given input variables. Then, numerical and graphical optimization was performed using RSM to obtain the target depth of penetration (DOP) and heat-affected zone (HAZ) width using desirability approach. Multiple regression models were developed based on the generated data, and then the models were used in GA to determine the optimum process parameters for achieving the target DOP and HAZ width. GA-based models employed two different selection processes. Both the RSM- and GA-based models suggested a number of solutions in terms of process parameters, and the identified solutions were validated by experiments. GA-based model employing tournament selection has been found to be a more accurate method for determining the optimum A-TIG welding process parameters.     

Thermoresponsive Conductivity of Graphene-Based Fibers

Smart materials are versatile material systems which exhibit a measurable response to external stimuli. Recently, smart material systems have been developed which incorporate graphene in order to share on its various advantageous properties, such as mechanical strength, electrical conductivity, and thermal conductivity as well as to achieve unique stimuli-dependent responses. Here, a graphene fiber-based smart material that exhibits reversible electrical conductivity switching at a relatively low temperature (60 °C), is reported. Using molecular dynamics (MD) simulation and density functional theory-based non-equilibrium Green's function (DFT-NEGF) approach, it is revealed that this thermo-response behavior is due to the change in configuration of amphiphilic triblock dispersant molecules occurring in the graphene fiber during heating or cooling. These conformational changes alter the total number of graphene-graphene contacts within the composite material system, and thus the electrical conductivity as well. Additionally, this graphene fiber fabrication approach uses a scalable, facile, water-based method, that makes it easy to modify material composition ratios. In all, this work represents an important step forward to enable complete functional tuning of graphene-based smart materials at the nanoscale while increasing commercialization viability.     

Synthesis of pure anatase TiO2 nanocrystals in SiO2 host and the determination of crystal planes by ImageJ

Anatase TiO₂ nanocrystals in the TiO₂- SiO₂ matrix were prepared by the ultra hydroylsis sol-gel route. The samples were heat treated at 350 °C and 500 °C. The structural analyses of the samples were carried out using X-ray diffraction technique, Raman spectroscopy and Transmission electron microscopy. The size of the nanocrystals from the XRD spectra (8.3 nm) and TEM (5-8 nm) is well in agreement. The spacing for the crystal planes was also determined using the ImageJ program. The Raman peaks further confirmed the formation of only the anatase phase within the matrix.     

Effects of alternating and direct current in electrocoagulation process on the removal of cadmium from water

In practice, direct current (DC) is used in an electrocoagulation processes. In this case, an impermeable oxide layer may form on the cathode as well as corrosion formation on the anode due to oxidation. This prevents the effective current transfer between the anode and cathode, so the efficiency of electrocoagulation processes declines. These disadvantages of DC have been diminished by adopting alternating current (AC) in electrocoagulation processes. The main objective of this study is to investigate the effects of AC and DC on the removal of cadmium from water using aluminum alloy as anode and cathode. The results showed that the removal efficiency of 97.5 and 96.2% with the energy consumption of 0.454 and 1.002 kWh kl⁻¹ was achieved at a current density of 0.2 A/dm² and pH of 7.0 using aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of cadmium was preferably fitting Langmuir adsorption isotherm, the adsorption process follows second order kinetics and the temperature studies showed that adsorption was exothermic and spontaneous in nature.     

Effect of interface, height and density of long vertically aligned carbon nanotube arrays on their thermal conductivity: an experimental study

The ever-growing need to dissipate larger amounts of heat from components and structures requires the development of novel materials with superior thermal conductivity. Aligned carbon nanotube arrays that are integrated in composite materials and structures may prove useful in increasing heat transfer through their thickness. Theoretical studies have shown the potential of carbon nanotubes to reach a thermal conductivity of 6600 Wm(-1)K(-1). Experimental results on the arrays however have shown much lower thermal conductivity values. A study was conducted to better understand heat conduction in mm-long carbon nanotube arrays and to experimentally determine their thermal conductivity. Emphasis was placed on the effect of various parameters including the height and density of the array and the thermal resistance at the array interface. A method was devised to measure the thermal conductivity of the array relying on Fourier's law while maintaining a steady state one-dimensional heat flow. The study reveals that the taller the array and the higher its density, the larger the thermal conductivity of the array. Quantitative data is also provided on the effect of various interface materials and their deposition technique on the thermal conductivity of the arrays.