Application of Appopolite in Adsorption of Heavy Metals (Co and Ni) from Waste Water

The optimum conditions for adsorption/ion exchange by using a batch method were evaluated by changing various parameters such as adsorbent amount, initial pH of the solution, mixing temperature and initial metal ions. The influence of the temperature on the ion-exchange/adsorption process was also examined. The Langmuir and Freundlich adsorption isotherm equations were derived from the basic empirical equations, and used for calculation of ion exchange parameters. Adsorption isotherms of Co2+ & Ni2+ ions could be best modelled by the Langmuir equation. The influences of contact time, metal initial concentration, adsorbent dosage concentration, and temperature have been studied. The adsorption efficiencies are found to be contact time dependent, increasing the contact time in the range of 20 180 min. The sorption equilibrium has attained between 60 and 180 min. Keywords - Adsorption, Freundlich adsorption isotherm, ion exchange, Langmuir equation, sorption equilibriu

Supercritical Fluid Technology in Biodiesel Production: A Review

The finite nature of fossil fuels necessitates consideration of alternative fuels from renewable sources. The term biofuel refers to liquid, gas and solid fuels predominantly produced from biomass. Biofuels include bioethanol, biomethanol, biodiesel and biohydrogen. Biodiesel, defined as the monoalkyl esters of vegetable oils or animal fats, is an attractive alternative fuel because it is environmentally friendly and can be synthesized from edible and non-edible oils. Various methods have been reported for the production of biodiesel from vegetable oil and fats such as Transesterification, non-catalytic Supercritical fluid technology, micro emulsion, pyrolysis etc. In this article, the potential of supercritical fluids (SCF) as a sustainable route for biodiesel production is discussed and compared with conventional catalytic reactions. Although, the advantages of catalyst free SCF process are apparent; there are concerns regarding the huge energy required to conduct supercritical reaction at elevated temperature and pressure. Hence, there are challenges facing SCF process which need to be addressed before it could be a sustainable technology in the future. Keywords: Supercritical fluid, Biodiesel, Biofuel, Non-catalytic, Alcohol

Mass and Heat Transfer in Solid Catalyst Bed

In heterogeneous catalysis much effort is put into the determination of the reaction kinetics. The primary of the kinetic research is either to be able to optimize the design of a reactor or to gain more insight on the fundamentals of a reaction. Since heterogeneous catalysis involves, by definition, at least two phases, exchange of heat and mass between the phases is required for the reaction to take place. Due to these transport phenomena, the observed rate at which the reaction takes place is not necessarily the same as its intrinsic rate, i.e. the unique rate for a given catalyst at given conditions. Thus, when investigating the reaction kinetics in a laboratory-scale catalytic reactor, one has to account for the factors that may generate a resistance to the reaction and that disguise the intrinsic kinetics. In solid catalyst beds heat and mass transfer presented by equations for the prediction of convective heat transfer, pressure drop, effective thermal conductivity and wall heat transfer whereas under the conditions of radiant heat transfer may be neglected. It having various applications in fluidized beds, packed beds, trickle beds, magnetically stabilized beds etc. Keywords: Heterogeneous Catalysis, Mass Transfer, Heat Transfer, Catalyst Bed

A Modular Single-phase Multistring Multilevel Inverter Topology for Distributed Energy Resources

AbstractThis Paper presents simulation analysis of single phase multilevel inverter for distributed energy resources(DER) system are small power generation tools, in order to reduce conversion losses, complexity of the circuit and to improve the size and cost of the system. The system involves a high step up converter is used to set up the voltage coming from the various DER's such as Fuel cell module and Photovoltaic module, this high voltage acts as input to the inverter. This system requires less number of switches as compare to conventional cascade H-bridge (CCHB) inverter. There are some advantages of this multilevel inverter such as improved output waveform, and lower Electromagnetic interference, lower switching power loss and Total Harmonic Distortion (THD)

A Report on Micro-invertebrates Associated with Littoral Macrophytes in Kagzipura Lake

The present study deals with micro-invertebrates associated with littoral macrophytes of kagzipura reservoir from January to December 2009.During the present study species of Protozoa, Rotifera, Copepoda, Cladocera and Ostracoda along with Sponges, Bryozoa. Nematodes and Insect larvae are recorded. This study will be helpful to understand the real picture of community structure of limnetic ecosystem

Theory for the coupling between longitudinal phonons and intrinsic Josephson oscillations in layered superconductors

In this publication a microscopic theory for the coupling of intrinsic Josephson oscillations in layered superconductors with longitudinal c-axis-phonons is developed. It is shown that the influence of lattice vibrations on the c-axis transport can be fully described by introducing an effective longitudinal dielectric function. Resonances in the I-V-characteristic appear at van Hove singularities of both acoustical and optical longitudinal phonon branches. This provides a natural explanation of the recently discovered subgap structures in the I-V-characteristic of highly anisotropic cuprate superconductors. The effect of the phonon dispersion on the damping of these resonances and the coupling of Josephson oscillations in different resistive junctions due to phonons are discussed in detail.Comment: submitted to Phys. Rev. B, corrections following referee repor

Simple models of small world networks with directed links

We investigate the effect of directed short and long range connections in a simple model of small world network. Our model is such that we can determine many quantities of interest by an exact analytical method. We calculate the function $V(T)$, defined as the number of sites affected up to time $T$ when a naive spreading process starts in the network. As opposed to shortcuts, the presence of un-favorable bonds has a negative effect on this quantity. Hence the spreading process may not be able to affect all the network. We define and calculate a quantity named the average size of accessible world in our model. The interplay of shortcuts, and un-favorable bonds on the small world properties is studied.Comment: 15 pages, 9 figures, published versio

Comparing initial-data sets for binary black holes

We compare the results of constructing binary black hole initial data with three different decompositions of the constraint equations of general relativity. For each decomposition we compute the initial data using a superposition of two Kerr-Schild black holes to fix the freely specifiable data. We find that these initial-data sets differ significantly, with the ADM energy varying by as much as 5% of the total mass. We find that all initial-data sets currently used for evolutions might contain unphysical gravitational radiation of the order of several percent of the total mass. This is comparable to the amount of gravitational-wave energy observed during the evolved collision. More astrophysically realistic initial data will require more careful choices of the freely specifiable data and boundary conditions for both the metric and extrinsic curvature. However, we find that the choice of extrinsic curvature affects the resulting data sets more strongly than the choice of conformal metric.Comment: 18 pages, 12 figures, accepted for publication in Phys. Rev.