Showing papers by "Indian Institute of Technology Guwahati published in 2008"
TL;DR: Fluorescence quenching showed that curcumin molecules quench the intrinsic fluorescence of caseins upon binding, and the utility of CMs as carriers ofCurcumin was evaluated by using in vitro cultured HeLa cells.
491 citations
TL;DR: In this article, polysulfone (PSf) membranes which had been modified for higher porosity and hydrophilicity through the use of additives such as polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) were used for removal of oil from the oily wastewater.
470 citations
TL;DR: This review discusses about rarely reviewed 24 plants reported to have antioxidant properties, which indicate that these plants could be source of dietary antioxidant supplies, which is another emerging area of research.
461 citations
TL;DR: In this article, polyethylene glycol (PEG) of three different molecular weights were used as the polymeric additives in the casting solution of polysulfone (PSf) by phase inversion method.
400 citations
TL;DR: A newly synthesized chitosan-Ag-nanoparticle composite was found to have significantly higher antimicrobial activity than its components at their respective concentrations.
368 citations
TL;DR: In this article, wind tunnel tests were conducted to assess the aerodynamic performance of single-, two-and three-stage Savonius rotor systems with both semicircular and twisted blades.
337 citations
TL;DR: In this paper, the effect of polyvinyl pyrrolidone (PVP) of different molecular weights on the structure and permeation properties of polysulfone (PSf) membranes was investigated.
322 citations
TL;DR: An improved degree of homogeneity of the resulting aggregate populations is demonstrated and a robust protocol is established for eliciting high EB formation efficiencies by optimizing a number of features: material composition of the microwells, cell seeding procedures, and aggregate retrieval methods.
293 citations
TL;DR: The use of polymer and solid-supported catalysts, ionic liquids and fluorous biphase systems (FBS) has been demonstrated to facilitate the recyclability of the catalysts as mentioned in this paper.
286 citations
TL;DR: The composite represents an ideal case of an environmentally friendly and stable catalyst, which works under heterogeneous as well as micro-heterogeneous conditions with the advantage of nanoscopic particles as the catalyst.
Abstract: In this paper, we report on the catalytic activity of a new metal nanoparticle–polymer composite consisting of Ag nanoparticles (NPs) and environmentally friendly ('green') chitosan. The polymer (chitosan) not only acted as the reducing agent for the metal ions, but also stabilized the product NPs by anchoring them. The majority of the particles produced in this way had sizes less than 5 nm. The catalytic activity of the composite was investigated photometrically by monitoring the reduction of 4-nitrophenol (4NP) in the presence of excess NaBH4 in water, under both heterogeneous and micro-heterogeneous conditions. The reaction was first order with respect to the concentration of 4NP. We also observed that the apparent rate constant, kapp, for the reaction was linearly dependent on the amount of Ag NPs present in the composite. Moreover, the turn-over frequency (TOF) of the catalyst was found to be (1.5 ± 0.3) × 10−3 s−1, when the reaction was carried out under heterogeneous conditions. The Ag NPs in the composite retained their catalytic activities even after using them for ten cycles. Our observations also suggest that the catalytic efficiency under micro-heterogeneous conditions is much higher than under heterogeneous conditions. Thus the composite we have represents an ideal case of an environmentally friendly and stable catalyst, which works under heterogeneous as well as micro-heterogeneous conditions with the advantage of nanoscopic particles as the catalyst.
272 citations
01 Jan 2008
TL;DR: By employing the proposed method the number of data required for learning in the ANFIS network could be significantly reduced and thereby computation time as well as computation complexity is remarkably reduced.
Abstract: Adaptive neural network based fuzzy inference system (ANFIS) is an intelligent neuro-fuzzy technique used for modelling and control of ill-defined and uncertain systems. ANFIS is based on the input-output data pairs of the system under consideration. The size of the input-output data set is very crucial when the data available is very less and the generation of data is a costly affair. Under such circumstances, optimization in the number of data used for learning is of prime concern. In this paper, we have proposed an ANFIS based system modelling where the number of data pairs employed for training is minimized by application of an engineering statistical technique called full factorial design. Our proposed method is experimentally validated by applying it to the benchmark Box and Jenkins gas furnace data and a data set collected from a thermal power plant of the North Eastern Electric Power Corporation (NEEPCO) Limited. By employing our proposed method the number of data required for learning in the ANFIS network could be significantly reduced and thereby computation time as well as computation complexity is remarkably reduced. The results obtained by applying our proposed method are compared with those obtained by using conventional ANFIS network. It was found that our model compares favourably well with conventional ANFIS model.
TL;DR: In this article, the authors reported the fabrication of stable low cost mesoporous membranes deploying subsequent formulations based on kaolin and other suitable low cost materials such as quartz, sodium carbonate, calcium carbonate and sodium metasilicate.
TL;DR: The utility of mPEG-PA to entrap the potent chemopreventive agent curcumin in the core of nanocarrier was investigated, which makes the drug readily soluble in an aqueous system, which can increase the ease of dosing and makes intravenous dosing possible.
TL;DR: It was observed that the removal of fluoride was better for bipolar connection than for monopolar connection, which might be useful in order to treat the fluoride contaminated water for drinking.
TL;DR: It has been found that both objective and subjective condition is important dimension of QOL and satisfaction from condition of traffic is the lowest among all satisfaction variables.
Abstract: This paper studies quality of life (QOL) in urban environment. The term environment has been used in broader sense, which includes physical, social and economic environment. A framework has been proposed which posits that QOL comprises objective condition of living and satisfaction from such living condition constitutes QOL. Such objective condition refers to objective QOL and satisfaction refers to subjective QOL. Dimension of QOL has been found to be multi dimensional. It has been found that both objective and subjective condition is important dimension of QOL. But correlation between objective and subjective QOL has been found not to be high. At the same time it has been found that satisfaction from condition of traffic is the lowest among all satisfaction variables.
University of New Mexico1, Indian Institute of Technology Guwahati2, Brookhaven National Laboratory3, TRIUMF4, University of British Columbia5, Tsinghua University6, Aristotle University of Thessaloniki7, Stony Brook University8, Fermilab9, Kyoto University10, University of Alberta11, University of Fukui12, Osaka University13, National Defense Academy of Japan14
TL;DR: Three events for the decay K+-->pi+nounu have been observed in the pion momentum region below the K+>pi+pi0 peak, 140 pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction as discussed by the authors.
Abstract: Three events for the decay K+-->pi+ nunu have been observed in the pion momentum region below the K+-->pi+pi0 peak, 140 pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction.
TL;DR: The EC process for removing Fe(II) from tap water is expected to be adaptable for household use and at the optimum total cost was 6.05 US$/m3.
TL;DR: NiCl2·6H2O efficiently catalyzes the C–S bond formation by the cross-coupling of aryl iodides with thiols in tetrabutylammonium bromide in excellent yield.
TL;DR: It is found that optimum particle concentration leads to programmed cell death in vitro and induction of the apoptotic pathway makes Ag NPs a representative of a new chemosensitization strategy for future application in gene therapy.
Abstract: The impact of manufactured nanomaterials on human health and the environment is a major concern for commercial use of nanotechnology based products. A judicious choice of selective usage, lower nanomaterial concentration and use in combination with conventional therapeutic materials may provide the best solution. For example, silver nanoparticles (Ag NPs) are known to be bactericidal and also cytotoxic to mammalian cells. Herein, we investigate the molecular mechanism of Ag NP mediated cytotoxicity in both cancer and non-cancer cells and find that optimum particle concentration leads to programmed cell death in vitro. Also, the benefit of the cytotoxic effects of Ag NPs was tested for therapeutic use in conjunction with conventional gene therapy. The synergistic effect of Ag NPs on the uracil phosphoribosyltransferase expression system sensitized the cells more towards treatment with the drug 5-fluorouracil. Induction of the apoptotic pathway makes Ag NPs a representative of a new chemosensitization strategy for future application in gene therapy.
TL;DR: In this article, short chain polyaniline (PANI) was synthesized on the surface of jute fiber and used as an adsorbent to remove hexavalent chromium (Cr(VI)).
TL;DR: A synthetic study and mechanistic proposal on the conversion of aromatic aldehyde, amine, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of BDMS leads to the formation of Mannich-type product A when R is a non-enolizable carbon or an alkoxy group.
Abstract: 1,3-Dicarbonyl compounds can be converted to Mannich-type products A or highly functionalized piperidines B in the presence of a catalytic amount of bromodimethylsulfonium bromide (BDMS). The combination of aromatic aldehyde, amine, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of BDMS leads to the formation of Mannich-type product A when R is a non-enolizable carbon or an alkoxy group, whereas in cases when R = CH3, the same combination yielded highly functionalized piperidines B. A synthetic study and mechanistic proposal are presented.
01 Mar 2008
TL;DR: It has been observed that inclusion of vibration signal along with thrust force and torque leads to better prediction of drill wear.
Abstract: In the present work, two different types of artificial neural network (ANN) architectures viz. back propagation neural network (BPNN) and radial basis function network (RBFN) have been used in an attempt to predict flank wear in drills. Flank wear in drill depends upon speed, feed rate, drill diameter and hence these parameters along with other derived parameters such as thrust force, torque and vibration have been used to predict flank wear using ANN. Effect of using increasing number of sensors in the efficacy of predicting drill wear by using ANN has been studied. It has been observed that inclusion of vibration signal along with thrust force and torque leads to better prediction of drill wear. The results obtained from the two different ANN architectures have been compared and some useful conclusions have been made.
TL;DR: In this article, a 2D transient conduction-radiation heat transfer problem is considered where the homogeneous medium is assumed to be absorbing, emitting and scattering, and three parameters, viz. the scattering albedo, the conduction radiation parameter and the boundary emissivity, are simultaneously estimated by the inverse method involving the lattice Boltzmann method (LBM) and the finite volume method (FVM) in conjunction with the GA.
Abstract: This article deals with the simultaneous estimation of parameters in a 2-D transient conduction–radiation heat transfer problem. The homogeneous medium is assumed to be absorbing, emitting and scattering. The boundaries of the enclosure are diffuse gray. Three parameters, viz. the scattering albedo, the conduction–radiation parameter and the boundary emissivity, are simultaneously estimated by the inverse method involving the lattice Boltzmann method (LBM) and the finite volume method (FVM) in conjunction with the genetic algorithm (GA). In the direct method, the FVM is used for computing the radiative information while the LBM is used to solve the energy equation. The temperature field obtained in the direct method is used in the inverse method for simultaneous estimation of unknown parameters using the LBM–FVM and the GA. The LBM–FVM–GA combination has been found to accurately predict the unknown parameters.
TL;DR: In this paper, the effect of these admixtures on rheological behavior of high performance concrete have been investigated and presented in this paper, it has been observed that yield stress decreases as the replacement level of rice husk ash and fly ash increases.
TL;DR: In this paper, the effects of initial dye concentration, contact time, kaolin dose, stirring speed, pH, and temperature are studied for the adsorption of crystal violet in batch mode.
Abstract: Experimental investigations are carried out to adsorb toxic crystal violet dye from aqueous medium using kaolin as an adsorbent. Characterization of kaolin is done by measuring particle size distribution using particle size analyzer, BET surface area using BET surface analyzer, structural analysis using X ray diffractometer, and microscopic analysis using scanning electron microscope. The effects of initial dye concentration, contact time, kaolin dose, stirring speed, pH, and temperature are studied for the adsorption of crystal violet in batch mode. Adsorption experiments indicate that the extent of adsorption is strongly dependent on the pH of the solution. Free energy of adsorption (ΔG o ), enthalpy (ΔH o ), and entropy (ΔS o ) changes are calculated to know the nature of adsorption. The calculated values of ΔG o are −4.11 and −4.48 kJ/mol at 295 K and 323 K, respectively, for 20 mg/L of dye concentration, which indicates that the adsorption process is spontaneous. The estimated values of ΔH o...
TL;DR: In this paper, a modified version of COSMO_LL has been used to predict the liquid-liquid equilibria (LLE) for 32 ternary systems, available in literature, each having an ionic liquid.
Abstract: Ionic liquids with their limitless combination of cations and anions can offer an optimal solvent for a specific purpose. But not all corresponding experimental studies are possible as they will be time consuming and expensive. A judicious screening of the various possible solvents is required to select the proper ionic liquid. Conductor-like screening model (COSMO) along with its extension to real solvents can be used for these predictions. In this work, modified version COSMO_LL has been used to predict the liquid–liquid equilibria (LLE) for 32 ternary systems, available in literature, each having an ionic liquid. A complete dissociation of cations and anions of the ionic liquid has been assumed. The root mean square deviation for all these systems is ∼9% which is excellent when compared with ∼50% obtained for predictions using the nondissociated composite molecule. Additionally, experimental LLE data has been collected for four ternary systems, namely: (a) 1-ethyl-3-methylimidazolium ethylsulphate [Emim] [EtSO4] – Ethanol-Hexene, (b) 1-ethyl-3-methylimidazolium ethylsulphate [Emim] [EtSO4] – Ethanol-Heptene, (c) 1,2-dimethyl-3-ethylimidazolium ethylsulphate [E-2,3-dmim] [EtSO4] – Ethanol-Hexene, and (d) 1,2-dimethyl-3-ethylimidazolium ethylsulphate [E-2,3-dmim] [EtSO4] – Ethanol-Heptene. The tie lines have been estimated using NMR and these have been compared with COSMO_LL predictions giving an average rmsd of ∼6%. © 2008 American Institute of Chemical Engineers AIChE J, 2008
01 Nov 2008
TL;DR: The current work concludes that LDA is not suitable for radar image based target recognition task, in line with reports from some works in the open literature which claim that the success of LDA will depend on the type of data and whether there is exhaustive data available during the training phase or not.
Abstract: Both principal component analysis (PCA) and linear discriminant analysis (LDA) have long been recognized as tools for feature extraction and data analysis. There has been reports in the open literature regarding the performance of both LDA and PCA as feature extractors in various types of classification and recognition problems. Many of the reports claim a better performance with LDA than with PCA. However, the grounds of comparison have mostly been quite narrow. In the current paper PCA and LDA based classifiers are evaluated for the problem of synthetic aperture radar based automatic target recognition problem. The results show that in terms of absolute performance, PCA outperforms LDA. Results of PCA based classifier are also found to be of higher confidence than those from LDA based classifiers, as observed from the error-bar analysis of the classifiers.With decreased amount of training dataset, the degradation in the performance of the classifiers are almost similar in nature. The current work concludes that LDA is not suitable for radar image based target recognition task. This is in line with reports from some works in the open literature which claim that the success of LDA will depend on the type of data and whether there is exhaustive data available during the training phase or not.
25 Feb 2008
TL;DR: It appears that maintaining a distinction between learning and fun to some extent is necessary for effective designs, and it is made the case that mobile games on cellphones is an appropriate solution in the typical ecologies of developing regions.
Abstract: Poor literacy remains a barrier to economic empowerment in the developing world. Of particular importance is fluency in a widely spoken "world language" such as English, which is typically a second language for these low-income learners. We make the case that mobile games on cellphones is an appropriate solution in the typical ecologies of developing regions. The challenge is to design e-learning games that are both educational and pleasurable for our target learners, who have limited familiarity with high technology. We propose the receptive-practice-activation cycle that could be used as the conceptual model for the designs. We then report how this format could be refined, based on our experiences in the field with three games that have collectively undergone nine rounds of iterations. In particular, it appears that maintaining a distinction between learning and fun to some extent is necessary for effective designs.
TL;DR: In this article, the application of the lattice Boltzmann method (LBM) to the analysis of natural convection in the presence of volumetric radiation in a square cavity containing an absorbing, emitting, and scattering medium is discussed.
Abstract: This article deals with the application of the lattice Boltzmann method (LBM) to the analysis of natural convection in the presence of volumetric radiation in a square cavity containing an absorbing, emitting, and scattering medium. Separate particle distribution functions in the LBM are used to calculate the density and velocity fields and the thermal field. The radiative term of the energy equation is computed using the finite-volume method. Streamlines, isotherms, and Nusselt number are analyzed for the effects of different parameters such as Rayleigh number, convection-radiation parameter, extinction coefficient, and scattering albedo.
21 Apr 2008
TL;DR: The characteristics of image spam are studied to propose two solutions for detecting image-based spam, and a novel approach for near duplication detection in images is offered.
Abstract: Email spam is a much studied topic, but even though current email spam detecting software has been gaining a competitive edge against text based email spam, new advances in spam generation have posed a new challenge: image-based spam. Image based spam is email which includes embedded images containing the spam messages, but in binary format. In this paper, we study the characteristics of image spam to propose two solutions for detecting image-based spam, while drawing a comparison with the existing techniques. The first solution, which uses the visual features for classification, offers an accuracy of about 98%, i.e. an improvement of at least 6% compared to existing solutions. SVMs (Support Vector Machines) are used to train classifiers using judiciously decided color, texture and shape features. The second solution offers a novel approach for near duplication detection in images. It involves clustering of image GMMs (Gaussian Mixture Models) based on the Agglomerative Information Bottleneck (AIB) principle, using Jensen-Shannon divergence (JS) as the distance measure.