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71.
A novel graft copolymer of [2-(methacryloyloxy)ethyl] trimethylammonium chloride onto poly(vinyl alcohol) has been synthesized
and it is cross-linked by glutaraldehyde for the investigation of its efficiency in removing Cr(VI) from aqueous solution.
The chemical nature of the ion-exchange resin has been elucidated with the help of chemical test, Fourier transform infrared,
thermo gravimetric analysis and DTA. Particle size, surface area, ion-exchange capacity, optimum pH, reaction time and temperature
for Cr(VI) extraction were determined. Chromium(VI) adsorption kinetics, isotherm and thermodynamics have been studied. A
plausible mechanism for chromium ion-exchange has been suggested. 相似文献
72.
Ru(II)–CO complexes of thioarylazoimidazoles: Syntheses,structures, spectroscopy and DFT calculation
T.K. Mondal P. Raghavaiah A.K. Patra C. Sinha 《Inorganic chemistry communications》2010,13(2):273-277
The complexes, cis-(CO)-trans-(Cl)-[Ru(SRaaiNR)(CO)2Cl2] (2) and trans-(Cl)-[Ru(SRaaiNR)(CO)Cl2] (3) (SRaaiNR = 1-alkyl-2-{(o-thioalkyl)phenylazo}imidazoles; R = Me (1a) and Et (1b)) have been synthesized and characterized. The structural confirmation is achieved by single crystal X-ray structure determinations. The complexes show Ru(III)/Ru(II) couple and ligand reductions. Electronic structure and spectral properties of the complexes have been explained with the DFT and TDDFT calculation. 相似文献
73.
Mohammad Shahjahan Mondal Jahir Uddin Chowdhury Md. Ruknul Ferdous 《Water Resources Management》2010,24(5):853-869
A risk-based evaluation is performed for meeting future water demands in the Brahmaputra Floodplain Area within Bangladesh
(BFA). This evaluation is carried out using three risk-based performance indicators: reliability, resiliency and vulnerability.
The vulnerability indicator has been redefined incorporating the aspect of a supply failure. The analysis includes the impacts
of climate change on both water demands and resources, and the generation of synthetic flows of the Brahmaputra River using
time series models. The simulated values of the indicators reveal that the expected demand of the BFA up to the year 2050
can be supplied with the proposed Brahmaputra Barrage inside Bangladesh under the ‘no change’ in climatic condition, provided
that the groundwater remains usable. However, if groundwater becomes unusable due to widespread arsenic contamination and/or
a climate change occurs, it would not be possible to meet the future water demand of the region with high reliability, moderate
resiliency and low vulnerability. 相似文献
74.
Subrata Mondal Asish Bandyopadhyay Pradip Kumar Pal 《The International Journal of Advanced Manufacturing Technology》2014,70(9-12):2151-2158
This paper presents an investigation on the optimization of multiple performance characteristics during CO2 laser cladding process considering clad width and clad depth as performance characteristics. This optimization for multiple quality characteristics has been done using Taguchi’s quality loss function. The process model for laser cladding operation using various techniques like artificial neural network (ANN) has rarely been found in the literature review. In the present work, a number of experiments have been performed to establish the interrelationship between process variables and response variables using the back propagation method of ANN. The essential input process parameters are identified as laser power, scan speed of work table, and powder feed rate. Moreover, the analysis of variance is also employed to determine the contribution of each control parameter on clad bead quality. In order to validate the predicted result, an experiment as confirmatory test is carried out at the optimized cladding condition. It is observed that the confirmatory experimental result is showing a good agreement with the predicted one. However, it has been found that the optimum condition of the cladding parameters for multi-performance characteristics varies with the different combinations of weighting factors. 相似文献
75.
Punyasloka Bal Bahniman Ghosh Partha Mondal M. W. Akram Ball Mukund Mani Tripathi 《Journal of Computational Electronics》2014,13(1):230-234
This paper proposes a junctionless tunnel field effect transistor (JLTFET) with dual material gate (DMG) structure and the performance was studied on the basis of energy band profile modulation. The two-dimensional simulation was carried out to show the effect of conduction band minima on the abruptness of transition between the ON and OFF states, which results in low subthreshold slope (SS). Appropriate selection of work function for source and drain side gate metal of a double metal gate JLTFET can also significantly reduce the subthreshold slope (SS), OFF state leakage and hence gives improved I ON/I OFF. 相似文献
76.
Investigation on Sodium Benzoate Release from Poly(Butylene Adipate‐Co‐Terephthalate)/Organoclay/Sodium Benzoate Based Nanocomposite Film and Their Antimicrobial Activity
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Dibyendu Mondal Biplab Bhowmick Dipanwita Maity Md. Masud R. Mollick Dipak Rana Vivek Rangarajan Ramkrishna Sen Dipankar Chattopadhyay 《Journal of food science》2015,80(3):E602-E609
Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate‐co‐terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium‐modified montmorillonite [CMMT]) in PBAT matrix was observed by X‐ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria. 相似文献
77.
In this article, we first propose the novel semi‐analytical technique—modified Adomian decomposition method (MADM)—for a closed‐form solution of the nonlinear heat transfer equation of convex profile with singularity where all thermal parameters are functions of temperature. The longitudinal convex fin is subjected to different boiling regimes, which are defined by particular values of n (power index) of heat transfer coefficient. The energy balance equation of the convex fin with several temperature‐dependent properties are solved separately using the MADM and the spectral quasi‐linearization method. Using the values obtained from the direct heat transfer method, the unknown parameters of the profile, such as thermal conductivity, surface emissivity, heat generation number, conduction‐convection parameter, and radiation‐conduction parameter are inversely predicted by an inverse heat transfer analysis using the simplex search method. The effect of the measurement error and the number of measurement points has been presented. It is found that present measurement points and reconstruction of the exact temperature distribution of the convex fin are fairly in good agreement. 相似文献
78.
It is apparent that non-Newtonian nanofluids (especially, Casson and Carreau) find their ubiquitous utilization in diverse industrial processes. The magnetohydrodynamics concept is significantly implemented in the engineering design process. Darcy–Forchheimer's effect characterized by inertia and boundary effects ameliorates the rate of heat transportation outstandingly in association with the flow of nanofluids. Entropy optimization analysis is accentuated as its minimization is the best measure to enhance the efficiency of thermal systems. In view of this, the present article is intended to investigate electromagnetic flow and thermal characteristics of Casson and Carreau nanofluids over the exponential stretched surface. Microrotation facets are entailed. Arrhenius pre-exponential factor law and Robin's condition are implemented. The nondimensional governing equations are solved by the spectral quasi-linearization method. The major outcomes of this study are that axial and transverse flow velocities and heat transfer rate get controlled due to strengthening Casson and microinertia density parameters. More thermal stratification augments the rate of heat transportation efficaciously. Amplification of the Weissenberg parameter intensifies the axial and transverse flow velocities and the associated boundary layer widths. Axial and transverse surface viscous drag enervate due to the rise in porosity, inertia, and magnetic parameters. The entropy generation rate is regulated by the varied Reynolds number. 相似文献
79.
Novel sol-gel derived calcium phosphate coatings on Mg4Y alloy 总被引:1,自引:0,他引:1
Abhijit RoySatish S. Singh Moni Kanchan DattaBoeun Lee J. OhodnickiPrashant N. Kumta 《Materials Science and Engineering: B》2011,176(20):1679-1689
Calcium phosphates (CaPs) and silicon containing calcium phosphates (Si-CaPs) coatings on a biodegradable magnesium yttrium alloy (Mg4Y) were prepared by a sol-gel technique to improve the bioactivity of the alloy surface. The experimental results show that thick porous coatings comprised of nano-sized calcium phosphate particles can be prepared by heating the as dip coated substrates at 450 °C. The in vitro degradation results show that the coatings do not alter the degradation kinetics of the substrates significantly and the release of magnesium and yttrium ions at initial time points was very similar for both the coated and bare substrates. The cyto-compatibility studies using MC3T3-E1 osteoblasts show that the coated substrates were more bioactive than the uncoated substrates as the cells begin to grow and form a matrix on the coated substrates more easily than on the bare metal. These preliminary results collectively show the potential of use of sol-gel derived calcium phosphate coatings on magnesium based degradable scaffolds to improve their surface bioactivity. 相似文献
80.
Mojammel H. Mondal 《Journal of Polymer Research》2017,24(12):218
Dynamic light scattering (DLS) of polymer and polymer–nanocomposite solutions has been performed to examine the effect in the morphology of polymer solution in presence of nanoparticles analyzing their correlation functions. The size of the nanoparticle was determined using UV–Vis absorption spectroscopy measurements. Analysis of the correlation functions of polymer solution shows existence of two modes, namely, fast and slow modes, along with the distinct values in their corresponding amplitudes and relaxation times. Interestingly, the fast mode of the solution was found to smear out, enhancing the slow mode when we grow nanoparticles into the polymer solution. Apart from the above study, the temperature variation study of both the solutions show that above and below room temperature, the polymer solution becomes more heterogeneous compared to the solution when nanoparticles are grown into it. 相似文献