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81.
Dinesh Kumar Mishra Jasaswini Tripathy Madan Mohan Mishra Kunj Behari 《应用聚合物科学杂志》2008,110(6):3455-3463
The optimum conditions for grafting N‐vinyl‐2‐pyrrolidone onto dextran initiated by a peroxydiphosphate/thiourea redox system were determined through the variation of the concentrations of N‐vinyl‐2‐pyrrolidone, hydrogen ion, potassium peroxydiphosphate, thiourea, and dextran along with the time and temperature. The grafting ratio increased as the concentration of N‐vinyl‐2‐pyrrolidone increased and reached the maximum value at 24 × 10?2 mol/dm3. Similarly, when the concentration of hydrogen ion increased, the grafting parameters increased from 3 × 10?3 to 5 × 10?3 mol/dm3 and attained the maximum value at 5 × 10?3 mol/dm3. The grafting ratio, add‐on, and efficiency increased continuously with the concentration of peroxydiphosphate increasing from 0.8 × 10?2 to 2.4 × 10?2 mol/dm3. When the concentration of thiourea increased from 0.4 × 10?2 to 2.0 × 10?2 mol/dm3, the grafting ratio attained the maximum value at 1.2 × 10?2 mol/dm3. The grafting parameters decreased continuously as the concentration of dextran increased from 0.6 to 1.4 g/dm3. An attempt was made to study some physicochemical properties in terms of metal‐ion sorption, swelling, and flocculation. Dextran‐g‐N‐vinyl‐2‐pyrrolidone was characterized with infrared spectroscopy and thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
82.
Thomas O.J. Blomfeldt Richard T. Olsson Mohan Menon David Plackett Eva Johansson Mikael S. Hedenqvist 《大分子材料与工程》2010,295(9):796-801
A new way of producing rigid or semi‐rigid foams from vital wheat gluten using a freeze‐drying process is reported. Water/gluten‐based mixtures were frozen and freeze‐dried. Different foam structures were obtained by varying the mixing process and wheat gluten concentration, or by adding glycerol or bacterial cellulose nanofibers. MIP revealed that the foams had mainly an open porosity peaking at 93%. The average pore diameter ranged between 20 and 73 µm; the sample with the highest wheat gluten concentration and no plasticizer had the smallest pores. Immersion tests with limonene revealed that the foams rapidly soaked up the liquid. An especially interesting feature of the low‐wheat‐concentration foams was the “in situ” created soft‐top‐rigid‐bottom foams.
83.
Kaustuvmani Patowary Moonjit Das Rupshikha Patowary Mohan Chandra Kalita Suresh Deka 《Journal of surfactants and detergents》2019,22(2):373-384
Production of a rhamnolipid biosurfactant (RBS) using discarded mixed bakery waste (BW) employing bacterial strain Pseudomonas aeruginosa strain PG1 (identified by 16 s rDNA sequencing) was investigated for bioconversion of the food waste. Dry and powder form BW was supplemented with mineral salt media (MSM) as a sole carbon source for production of RBS. RBS production was measured based on the drop collapse assay and surface tension (ST) reduction of the culture media. Production of RBS in the culture media was enhanced by optimizing the carbon source (BW) concentration and the proper nitrogen source along with the pH of the MSM. Under optimized culture conditions, 11.56 g L−1 day−1 crude biosurfactant (BS) was achieved. The RBS had the ability to reduce the ST of the optimized MSM from 72.0 to 25.8 mN m−1 during culture, where the critical micelle concentration (CMC) of the biosurfactant was found to be 100 mg L−1. Liquid Chromatography Mass Spectroscopy (LC-MS), Fourier Transform Infrared spectroscopy (FTIR), and scanning electron microscopy (SEM)–energy dispersive X-ray spectroscopy (EDS) analyses of the purified BS confirmed that it is of rhamnolipid in nature and it is made up of both monorhamnolipid and dirhamnolipid congeners. Furthermore, the RBS did not express any cytotoxic effect on the cell line of mouse L292 fibroblastic cell indicating the biosafety nature of the high-value biomolecule. 相似文献
84.
Mohan B. Ponnuchamy G. Mohan Muralikrishna Venkateswara Rao Mannava G. Srinivas Reddy 《Ceramics International》2018,44(13):15019-15023
Nanocrystalline nickel oxide (NiO) was prepared from nickel hydroxide by Spark plasma sintering (SPS) and the mechanisms involved in the densification of NiO were studied. Reverse precipitated nickel hydroxide powders were SPS processed at 400, 600 and 700?°C with 70?MPa pressure. Pure NiO with 12?nm crystallite size formed after 400?°C sintering process. However NiO grains had grown to 18 and 38?nm after 600 and 700?°C sintering respectively. NiO pellets prepared using 600 and 700?°C SPS sintering schedules had relative densities of 83% and 94% respectively. Two displacement rate regimes were observed during densification of NiO in both 600 and 700?°C sintering processes. Decomposition of nickel hydroxide and particle sliding of NiO led to first displacement rate maximum while inverse Hall-Petch based plastic deformation facilitated densification during the constant second displacement rate regime. No densification occurred during sintering holding times indicating the limited role that diffusion played during densification. 相似文献
85.
86.
Debosruti Dutta Wei-Hung Chiang R.Mohan Sankaran Venkat R. Bhethanabotla 《Carbon》2012,50(10):3766-3773
An epitaxial nucleation model for single-walled carbon nanotube (SWCNT) growth on bimetallic catalysts surfaces is reported in support of experimental observations of chiral enrichment. We model the bimetallic catalyst surfaces as a 2D (1 1 1) surface consisting of Ni or a combination of Ni and Fe atoms, with varying average bond length between nearest neighbor atoms which corresponds to the crystal structure of the alloys. The energies associated with nanotube cap formation on these various surfaces are calculated using density functional theory (DFT). We find that certain cap chiralities, such as (8, 4), are more stably bound to a surface that resembles a Ni0.27Fe0.73 bimetallic catalyst, whereas other chiralities, such as (9, 4), are more stable on a pure Ni surface. These results help explain the predominance of certain chiralities on specific bimetallic catalysts and provide a potential route to controlling the chirality of as-grown SWCNTs. 相似文献
87.
De-duplication using biometrics has gained much attention from research communities as it provides a unique identity for each and every individual among the large population.De-duplication is the process of removing the instances of multiple enrollments by the same person using the person’s biometric data.An important issue in the large-scale de-duplication applications is the speed of matching and the accuracy of the matching because the number of persons to be enrolled runs into millions.This paper presents an efficient method to improve the accuracy of fingerprint de-duplication in de-centralized manner.De-duplication accuracy decreases because of the noise present in the data,which would cause improper slap fingerprint segmentation.In this paper,an attempt is made to remove the noise present in the data by using binarization of slap fingerprint images and region labeling of desired regions with 8-adjacency neighborhood.The distinct feature of this technique is to remove the noise present in the data for an accurate slap fingerprint segmentation and improve the de-duplication accuracy.Experimental results demonstrate that the fingerprint segmentation rate and de-duplication accuracy are improved significantly. 相似文献
88.
Ketan Pancholi Nassim Ahras Eleanor Stride Mohan Edirisinghe 《Journal of materials science. Materials in medicine》2009,20(4):917-923
Uniform spherical chitosan particles of size <10 μm in diameter are important in drug delivery applications due to their excellent
biocompability and biodegradability. A high concentration of chitosan in the particles can help to control the release of
drugs and methods for processing high viscosity chitosan solutions are therefore required. In principle, any type of polymer,
whether hydrophobic or hydrophilic, can be electrosprayed to obtain monodisperse particles of diameter <10 μm. In practice,
however, electrospraying of biopolymers having viscosities of >100 mPa s results in particles >10 μm diameter. In this study,
by reducing surface tension of a high viscosity chitosan suspension, it was found that smaller diameter particles could be
prepared. Chitosan solutions were electrosprayed in the stable cone-jet mode to systematically study the relationship between
particle diameter, viscosity and surface tension. Increasing viscosity resulted in larger diameter particles with a broad
size distribution, but decreasing surface tension had the opposite effect. Results show that a chitosan solution having a
viscosity of ~80 mPa s can be used to prepare chitosan particles of diameter ~2.5 μm which on drying reduced to particles
of 500 nm. 相似文献
89.
K. Deep Krishna Pratap Singh M. L. Kansal C. Mohan 《Water Resources Management》2009,23(14):2987-3003
In this paper a fuzzy interactive method is proposed for efficient management of multipurpose multireservoir problems. The
proposed method provides an option to decision maker (DM) to work in an interactive manner to achieve the conflicting objectives
as close to their desired values as is practically feasible. In each iteration, fuzzy membership functions of various objectives
are framed and combined into a single objective using the product operator. The single objective nonlinear optimization model
thus framed in each iteration is numerically solved using genetic algorithm. The solution provides the values of the objectives
which can be actually achieved keeping in view their aspired values as provided by DM. At the end of each iteration, DM has
the option to modify the aspired values of one or more objectives keeping in view the results obtained by the algorithm thus
far. The algorithm is stopped when DM feels satisfied with the results. The working of the proposed method has been demonstrated
on the mathematical model of a realistic multipurpose multireservoir system taken from literature. 相似文献
90.
A. Mohan BabuB.C. Jamalaiah J. Suresh KumarT. Sasikala L. Rama Moorthy 《Journal of Alloys and Compounds》2011,509(2):457-462
Lead tungsten tellurite (LTT) glasses doped with different Dy3+ ion concentrations have been prepared and characterized through optical absorption, photoluminescence and decay measurements. The glassy nature of the LTT host has been confirmed through the XRD measurements. The three phenomelogical intensity parameters Ωλ (λ = 2, 4, 6) have been determined from the absorption spectral intensities using the Judd-Ofelt (J-O) theory. The hypersensitivity of 6H15/2 → 6F11/2 transition based on the magnitude of Ω2 parameter has also been discussed. By using the J-O intensity parameters several radiative properties such as spontaneous transition probabilities (AR), fluorescence branching ratios (βR) and radiative lifetimes (τR) have been determined. The effect of Dy3+ ion concentration on the emission intensities of 4F9/2 → 6HJ′ (J′ = 15/2, 13/2, 11/2 and 9/2) transitions has also been reported. 相似文献