Showing papers by "Indian Institute of Technology Guwahati published in 2010"
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TL;DR: In this paper, a review of cost effective technologies and the processes to convert biomass into useful liquid bio-fuels and bioproducts, with particular focus on some biorefinery concepts based on different feedstocks aiming at the integral utilization of these feedstocks for the production of value added chemicals.
Abstract: Sustainable economic and industrial growth requires safe, sustainable resources of energy. For the future re-arrangement of a sustainable economy to biological raw materials, completely new approaches in research and development, production, and economy are necessary. The ‘first-generation’ biofuels appear unsustainable because of the potential stress that their production places on food commodities. For organic chemicals and materials these needs to follow a biorefinery model under environmentally sustainable conditions. Where these operate at present, their product range is largely limited to simple materials (i.e. cellulose, ethanol, and biofuels). Second generation biorefineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing including pyrolysis, Fisher Tropsch, and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This review focus on cost effective technologies and the processes to convert biomass into useful liquid biofuels and bioproducts, with particular focus on some biorefinery concepts based on different feedstocks aiming at the integral utilization of these feedstocks for the production of value added chemicals.
2,814 citations
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TL;DR: A cytotoxicity assay showed that composite NPs at a concentration of 500 microg/mL were nontoxic to HeLa cells, and cellular internalization of curcumin loaded composite nanoparticles was confirmed from green fluorescence inside the He La cells.
567 citations
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TL;DR: This paper reviews the application of neural networks, fuzzy sets, genetic algorithms, simulated annealing, ant colony optimization, and particle swarm optimization to four machining processes—turning, milling, drilling, and grinding.
Abstract: Machining is one of the most important and widely used manufacturing processes. Due to complexity and uncertainty of the machining processes, of late, soft computing techniques are being preferred to physics-based models for predicting the performance of the machining processes and optimizing them. Major soft computing tools applied for this purpose are neural networks, fuzzy sets, genetic algorithms, simulated annealing, ant colony optimization, and particle swarm optimization. The present paper reviews the application of these tools to four machining processes—turning, milling, drilling, and grinding. The paper highlights the progress made in this area and discusses the issues that need to be addressed.
327 citations
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TL;DR: In this article, the authors highlight the technical and economical issues related to decentralized power generation in India using biomass gasification and discuss principal factors influencing the viability of the biomass-based power generation.
Abstract: This article attempts to highlight the technical and economical issues related to decentralized power generation in India using biomass gasification. Biomass-based energy has several distinct advantages such as wide availability and uniform distribution that puts it ahead among the renewable energy options for India. The estimated potential of power generation through renewable sources in India is 85 GW with biomass power contributing approximately 20 GW. Especially, in the remote areas and hilly terrains of India, biomass gasification-based power generation offers a highly viable solution for meeting energy demands of small villages and hamlets, which would not only make them independent but will also reduce burden on state electricity boards. This paper reviews various technical options for biomass gasification-based low-, medium- and large-scale power generation. We essentially discuss the merits and demerits (operational and other problems) of different systems. Further, we also deal with economics of these systems and discuss principal factors influencing the viability of the biomass-based power generation. Finally, we review some case studies of biomass-based power generation for meeting energy needs, both thermal and electrical.
288 citations
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TL;DR: The prominent mechanism of lipid extraction was diffusion across a cell wall and the selectivity of the solvent was found to be the most dominating factor in overall lipid extraction by diffusion than the intensity of bulk convection in the medium.
Abstract: In this paper, we have attempted to make a comparative assessment of the three techniques for extraction of lipids from microalgal biomass, viz. Soxhlet extraction, the Bligh and Dyer method, and sonication. The approach is mechanistic in the sense that we have tried to determine the physical mechanism of extraction of lipids (cell disruption or diffusion across a cell wall) from microalgae using microscopic analysis of extracted biomass. We have also assessed the relative influence of the solvent (or extractant) selectivity and the intensity of convection in the medium on the overall lipid yield. None of the techniques used produced complete disruption of the cells, not even sonication. Thus, the prominent mechanism of lipid extraction was diffusion across a cell wall. Moreover, the selectivity of the solvent was found to be the most dominating factor in overall lipid extraction by diffusion than the intensity of bulk convection in the medium.
222 citations
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TL;DR: The gene expression study revealed that Ag NP induced p53-mediated apoptotic pathway through which most of the chemotherapeutic drugs trigger apoptosis (programmed cell death) and the results suggest that Ag NPs could be attributed as therapeutic agent for biomedical and pharmaceutical applications.
203 citations
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TL;DR: In this paper, the authors focused on the treatment of oily wastewater coming out from the post-treatment unit of petroleum industries using cross-flow mode of ultrafiltration using four types of polysulfone (PSf) membranes which had been synthesized using different combinations of additives and solvents.
173 citations
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TL;DR: Experimental evidence indicates significantly high bactericidal activity of the nanocomposite in the presence of iodine than either due to the composite, chitosan, Ag NP or iodine only, and elucidation of the mechanism of synergy suggested that on the surface of Ag NPs molecular iodine possibly generated iodine atom thus contributing toward free radical induced oxidative stress.
Abstract: Herein we report synergy in antimicrobial activity of a chitosan−silver nanoparticle (CS−Ag NP) composite in the presence of molecular iodine. Green fluorescent protein (GFP) expressing recombinant Escherichia coli bacteria have been used to test the efficacy and establish the mechanism of action. Experimental evidence indicate significantly high bactericidal activity of the nanocomposite in the presence of iodine than either due to the composite, chitosan, Ag NP or iodine only. Transmission electron microscopy measurements revealed attachment of bacteria to the composite. In addition, flow cytometry results supported definite occurrence of cell wall damage of the bacteria treated with the composite in the presence of iodine. Further, the nanocomposite and iodine combination was found to exert reactive oxygen species (ROS) generated oxidative stress in the cytoplasm of bacterial cells, leading to cell death. Elucidation of the mechanism of synergy due to three potential antibacterial components suggested ...
172 citations
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TL;DR: The study establishes Zingiberaceae as a medicinal family since 41% of all the available Zingibereceae of North-eastern states were found to possess medicinal value.
168 citations
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TL;DR: In this paper, the diameter dependent spectral features in X-ray diffraction (XRD) and Raman scattering studies of multiwalled carbon nanotubes (MWCNTs) of various diameters in the range 5−100nm were analyzed.
167 citations
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TL;DR: Modeling of the biodegradation of phenol indicates that the Haldane inhibitory model predicts the experimental data fairly well for both the strains.
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TL;DR: In this paper, a study of the decay mode X(3872)→J/ψω, with product branching fractions B(B^+→X( 3872)K^+π^-π^0K^(0,+), using 467×10^6 BB[overbar] pairs recorded with the BABAR detector.
Abstract: We present a study of the decays B^(0,+)→J/ψπ^+π^-π^0K^(0,+), using 467×10^6 BB[overbar] pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872)→J/ψω, with product branching fractions B(B^+→X(3872)K^+)×B(X(3872)→J/ψω)=[0.6±0.2(stat)±0.1(syst)]×10^(-5), and B(B^0→X(3872)K^0)×B(X(3872)→J/ψω)=[0.6±0.3(stat)±0.1(syst)]×10^(-5). A detailed study of the π^+π^-π^0 mass distribution from X(3872) decay favors a negative-parity assignment.
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TL;DR: In this paper, the performance and modeling of the separation of oil-in-water (o/w) emulsions using low cost ceramic membrane that was prepared from inorganic precursors such as kaolin, quartz, feldspar, sodium carbonate, boric acid and sodium metasilicate was addressed.
Abstract: This work addresses the performance and modeling of the separation of oil-in-water (o/w) emulsions using low cost ceramic membrane that was prepared from inorganic precursors such as kaolin, quartz, feldspar, sodium carbonate, boric acid and sodium metasilicate. Synthetic o/w emulsions constituting 125 and 250 mg/L oil concentrations were subjected to microfiltration (MF) using this membrane in batch mode of operation with varying trans-membrane pressure differentials (ΔP) ranging from 68.95 to 275.8 kPa. The membrane exhibited 98.8% oil rejection efficiency and 5.36 × 10−6 m3/m2 s permeate flux after 60 min of experimental run at 68.95 kPa trans-membrane pressure and 250 mg/L initial oil concentration. These experimental investigations confirmed the applicability of the prepared membrane in the treatment of o/w emulsions to yield permeate streams that can meet stricter environmental legislations (
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TL;DR: These studies proved that compounds 1'-(p-chlorophenyl)-2'-(2-thienylcarbonyl)-spiro[3H-indole-3,3'-[ 3H]pyrrolizin]-2-one against Salmonella typhi show maximum inhibition potency at low concentration whereas 4d against Candida albicans and 4b and 4D against Rhizopus sp. showed beneficial antifungal activity at minimum concentration.
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TL;DR: In this article, a novel use of the ethanolic leaf extract of Centella asiatica to produce gold nanoparticles by reduction of AuCl4− ions was reported.
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TL;DR: In this paper, the effects of binding and conformational changes induced by the neutral amphiphilic ligand [5-(alkoxy)naphthalen-1-amine] with different alkyl chain lengths on bovine serum albumin (BSA) have been studied using UV−visible and fluorescence spectroscopic methods.
Abstract: The effects of binding and conformational changes induced by the neutral amphiphilic ligand [5-(alkoxy)naphthalen-1-amine] with different alkyl chain lengths on bovine serum albumin (BSA) have been studied using UV−visible and fluorescence spectroscopic methods. The BSA fluorescence exhibits appreciable bathochromic shift along with a reduction in fluorescence intensity and fluorescence lifetime upon binding with ligands. Ligand quenches the fluorescence of BSA in a concentration-dependent manner and deviates positively from the linear Stern−Volmer equation. The calculated quenching rate constants and binding constants were shown to depend entirely on the alkyl chain length of the ligands. After binding of probes with protein, the distance between the donor and acceptor was calculated using Forster theory. Ligands bind near Trp-134 in the subdomain IA of the native BSA and they become accessible to Trp-212 when BSA gets unfolded. The spectral data well supports the idea that BSA changes its three-dimensio...
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TL;DR: A review of metal hydride-based heating and cooling systems can be found in this paper, where the authors provide guidance regarding various design parameters and operation principles of various types of systems and emphasize the importance of the reaction bed heat and mass transfer characteristics.
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TL;DR: A wavelet-based bilateral filtering scheme for noise reduction in magnetic resonance images that has been adapted specifically to Rician noise and the visual and the diagnostic quality of the denoised image is well preserved.
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TL;DR: This methodology provides an alternative approach for easy access of highly and fully substituted piperidines in moderate to good yields using three readily available starting materials and is environmentally friendly as compared to the existing methods.
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TL;DR: The results of emulsifying activity and stability of the product against the tested organic solvents and oils together with its ability to solubilize fat and oil confirmed the potential of the biosurfactant in environmental applications.
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TL;DR: Tetrabutylammonium tribromide (TBATB) has been found to be an efficient catalyst for the one-pot synthesis of highly substituted piperidines through a combination of 1,3-dicarbonyl compounds, aromatic aldehydes, and various amines in ethanol at room temperature as mentioned in this paper.
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TL;DR: In this article, the infinite dilution activity coefficient (IDAC) was predicted through the conductor-like screening model for real solvents (COSMO-RS) model in order to screen the potential anions.
Abstract: Five- and six-membered heteroaromatic nitrogen compounds play an inhibiting role in the hydrodesulfurization of diesel oil. In this work, the ionic liquids (ILs) are used as green solvents to remove such compounds by liquid−liquid extraction (LLE). Approximately 168 ILs comprising cations which include 1-ethyl-3-methylimidaozlium [EMIM], 1-ethylpyridinium [EPY], 1-ethyl-1-methyl pyrrolidinium [EPYRO], 1-ethyl-1-methylpiperidinium [EMPIP], 4-ethyl-4-methyl morpholinium [EMMOR], and 1,2,4-trimethylpyrazolium[TMPYZO] combined with 26 anions were investigated in this work. The infinite dilution activity coefficient (IDAC) was predicted through the conductor-like screening model for real solvents (COSMO-RS) model in order to screen the potential solvents. Initially the model was benchmarked via IDAC and LLE predictions. LLE was predicted for four reported ternary systems in which a nitrogen heterocycle was one of the compounds. The average root-mean-square deviation (rmsd) obtained was 10%. The IDAC values wer...
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TL;DR: The cobalt(ii)-complex catalyzes efficiently the intramolecular C-N and C-O cross-couplings of Z-N'-(2-halophenyl)-N-phenylamidines and N-(2-bromophenyl)benzamides to afford the corresponding substituted benzimidazoles and benzoxazoles in the presence of K(2)CO(3) at moderate temperature.
Abstract: Cobalt(II)-complex catalyzes efficiently the intramolecular C–N and C–O cross-couplings of Z-N′-(2-halophenyl)-N-phenylamidines and N-(2-bromophenyl)benzamides to afford the corresponding substituted benzimidazoles and benzoxazoles in the presence of K2CO3 at moderate temperature. The protocol is general, air stable and affords the products selectively in moderate to high yield.
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TL;DR: It is shown that satisfactory closed loop performances for a class of integrating processes are obtained if the ISE criterion is minimized with the constraint that the slope of the Nyquist curve has a specified value at the gain crossover frequency.
Abstract: Minimizing the integral squared error (ISE) criterion to get the optimal controller parameters results in a PD controller for integrating processes. The PD controller gives good servo response but fails to reject the load disturbances. In this paper, it is shown that satisfactory closed loop performances for a class of integrating processes are obtained if the ISE criterion is minimized with the constraint that the slope of the Nyquist curve has a specified value at the gain crossover frequency. Guidelines are provided for selecting the gain crossover frequency and the slope of the Nyquist curve. The proposed method is compared with some of the existing methods to control integrating plant transfer functions and in the examples taken it always gave better results for the load disturbance rejection whilst maintaining satisfactory setpoint response. For ease of use, analytical expressions correlating the controller parameters to plant model parameters are also given.
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TL;DR: In this article, the use of the lattice Boltzmann method (LBM) has been extended to analyze radiative transport problems in an absorbing, emitting, and scattering medium.
Abstract: Use of the lattice Boltzmann method (LBM) has been extended to analyze radiative transport problems in an absorbing, emitting, and scattering medium. In terms of collision and streaming, the present approach of the LBM for radiative heat transfer is similar to those being used in fluid dynamics and heat transfer for the analyses of conduction and convection problems. However, to mitigate the effect of the isotropy in the polar direction, in the present LBM approach, lattices with more number of directions than those being used for the 2-D system have been employed. The LBM formulation has been validated by solving benchmark radiative equilibrium problems in 1-D and 2-D Cartesian geometry. Temperature and heat flux distributions have been obtained for a wide range of extinction coefficients. The LBM results have been compared against the results obtained from the finite-volume method (FVM). Good comparison has been obtained. The numbers of iterations and CPU times for the LBM and the FVM have also been com...
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TL;DR: It is observed that the proposed denoising scheme not only filters the signal effectively but also helps retain the diagnostic information.
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TL;DR: In this article, the authors studied optical solitons with non-Kerr law nonlinearity, in the presence of inter-modal dispersion, and they considered the types of nonlinearities that are considered are Kerr, power, parabolic and dual-power laws.
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TL;DR: In this paper, the palladium-catalyzed one-pot conversion of aldehydes into primary amides in the presence of hydroxylamine hydrochloride in aqueous dimethyl sulfoxide (DMSO) at moderate temperature is described.
Abstract: The palladium-catalyzed one-pot conversion of aldehydes into primary amides in the presence of hydroxylamine hydrochloride in aqueous dimethyl sulfoxide (DMSO) at moderate temperature is described. The process is selective and free from the addition of an external chelating ligand.
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TL;DR: In this paper, composite bipolar plates for fuel cells were prepared by a compression molding technique using novolac type phenol formaldehyde resin as a binder and natural graphite, carbon black and carbon fiber as reinforcements.
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TL;DR: The proposed algorithms for ECG based classification of arrhythmia proved to be patient independent in the sense that the performance is good even when the test ECG signal is from a patient whose ECG is not present in the training ECG dataset.