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Effect of mixing on shear rheology of EVA nanocomposites
Rahul K Gupta,Sati N. Bhattacharya 한국유변학회 2010 Korea-Australia rheology journal Vol.22 No.3
EVAs with VA contents of 9%, 18%, 28% and 40% by weight and commercially modified montmorillonite clay were melt compounded in a twin-screw extruder. Nanocomposites of different clay loadings (2 to 7.5wt%) were produced. Two mixing techniques were used to produce these EVA nanocomposites. WAXS measurements have revealed that EVA chains had intercalated into the silicate layers and expanded the interlayer distance. TEM showed that the morphologies of the nanocomposites were of mixed intercalated /exfoliated. Shear rheology was employed to investigate elastic issues related to different EVA nanocomposites. Elasticity of the nanocomposites was compared using first normal stress difference-shear stress plots. The exfoliated morphology shown by EVA28 nanocomposites demonstrated that normal stress difference decreases as shear stress increases.
Rahul k.Gupta,Amita Bhatia,Sati.N.Bhattacharya,최형진 한국유변학회 2007 Korea-Australia rheology journal Vol.19 No.3
Biodegradable polymeric blends are expected to be widely used by industry due to their environmental friendliness and comparable mechanical and thermal properties. Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) are such biodegradable polymers which aim to replace commodity polymers in future applications. Since cost and brittleness of PLA is quite high, it is not economically feasible to use it alone for day to day use as a packaging material without blending. In this study, blends of PLA and PBS with various compositions were prepared by using a laboratory-scale twin-screw extruder at 180oC. Morphological, thermal, rheological and mechanical properties were investigated on the samples obtained by compression molding to explore suitability of these compositions for packaging applications. Morphology of the blends was investigated by scanning electron microscopy (SEM). Morphology showed a clear phase difference trend depending on blend composition. Modulated differential scanning calorimetry (MDSC) thermograms of the blends indicated that the glass transition temperature (Tg) of PLA did not change much with the addition of PBS, but analysis showed that for PLA/PBS blend of up to 80/20 composition there is partial miscibility between the two polymers. The tensile strength and modulus were measured by the Instron Universal Testing Machine. Tensile strength, modulus and percentage (%) elongation at break of the blends decreased with PBS content. However, tensile strength and modulus values of PLA/PBS blend for up to 80/20 composition nearly follow the mixing rule. Rheological results also show miscibility between the two polymers for PBS composition less than 20% by weight. PBS reduced the brittleness of PLA, thus making it a contender to replace plastics for packaging applications. This work found a partial miscibility between PBS and PLA by investigating thermal, mechanical and morphological properties.
Singh, Rahul,Bhattacharya, B.,Gupta, Meenal,Rahul, Meenal,Khan, Zishan H.,Tomar, S.K.,Singh, Vijay,Singh, Pramod K. Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.21
<P><B>Abstract</B></P> <P>This paper reports the synthesis, characterization and dual electrochemical application of a new kind of ionic liquid (IL) based polymer electrolyte. The ionic liquid 1, 2-dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide (DMPImTFSI) and polymer Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) have been chosen for present study. The electrical conductivity measurement shows many fold enhancement of ionic conductivity by blending IL into polymer matrix. Scanning electron microscopy (SEM) image confirms the uniform surface morphology of the synthesized thin film and cross-section image shows the interface layer of polymer and electrode. We have fabricated an efficient dye sensitized solar cell (DSSC) and electric double layer capacitor (EDLC) using IL-polymer electrolyte (optimized maximum conductivity) system which further affirms that this material is highly stable and reliable for long duration in energy devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel polymer gel electrolyte system for dual energy storage electrochemical application. </LI> <LI> Liquid like ionic conductivity of gel polymer electrolyte with high transparency in the film. </LI> <LI> Highly stable electrical performance of DSSC and EDLC devices. </LI> </UL> </P>
Behl, Rahul,Behl, Jyotsna,Gupta, Neelam,Gupta, S.C.,Ahlawat, S.P.S. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.1
The capability of microsatellite markers for individual identification and their potential for breed assignment of individuals was evaluated in two Indian horse breeds. The strength of these individual assignment methods was also evaluated by increasing the number of loci in increments of five. The probability of identity of two random horses from the two breeds at all twenty five studied loci was as low as $1.08{\times}10^{-32}$ showing their suitability to distinguish between individual horses and their products. In the phylogenetic approach for individual assignment using Nei's genetic distances, 10.81% of horses associated with breed other than the major cluster of the source breed horses when all twenty five microsatellite loci were implemented. Similar results were obtained when the maximum likelihood approach for individual assignment was used. Based on these results it is proposed that, although microsatellite markers may prove very useful for individual identification, their utility for breed assignment of horses needs further evaluation.
( Rajesh Gupta ),( Aditya Atul Kulkarni ),( Rahul Gupta ),( Sunil Shenvi ),( Tanvi Jain ),( Raghavendra Babu ),( Mandeep Kang ),( Surinder Rana ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1
Aims: Step-up approach is becoming a standard of care for management of acute necrotizing pancreatitis. We aimed to investigate the learning curve effect and increasing experience on management and outcomes of surgical step-up approach at our high-volume tertiary referral center. Methods: In a retrospective analysis of database of patients with acute necrotizing pancreatitis referred to our unit, we divided patients into three distinct time periods: Group-1 (2008-2012), Group-2 (2013-2016) and Group-3 (2017-2019). Outcomes between different time periods were compared. Results: Total of 335 patients were included, with 92 patients in Group-1, 117 in Group-2 and 126 in Group-3. Patients treated on surgical side in later time period had higher incidence of multiorgan failure (26.1% vs. 49.6% vs. 45.2%, P<0.001), APACHE II scores at presentation (8 vs. 10 vs. 9, P=0.006) and at first intervention (9 vs. 11 vs. 10, P=0.037), as well higher mCTSI score (8 vs. 10 vs. 10, P<0.001). Over time, median percutaneous drain size (10Fr vs. 12Fr vs. 14 Fr, P<0.001) as well as sepsis reversal after drainage (40.2% vs. 59% vs. 49.2%, P=0.026) increased, whereas median number of drains (P=0.001) and interventions (4 vs. 3 vs. 3, P=0.005) decreased significantly. Necrosectomy requirement, length of stay and mortality remained similar over time despite more severe cases referred to surgical side. Conclusions: With increasing experience of step-up approach, sicker patients with higher severity of pancreatitis could be managed successfully with fewer drains and procedures leading to significantly higher sepsis reversal with drainage, with no increase in surgery requirement or mortality.
Gupta, Ragini,Jain, Anshu,Jain, Meenakshi,Joshi, Rahul Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.11
A simple facile 'one pot' synthesis of 2-amino-3-cyano-4,6-diarylpyridine derivatives via three component reaction of chalcone, malanonitrile and ammonium acetate under ultrasonic irradiation and grindstone technology. All the synthesized compounds have been characterized on the basis of their elemental analyses and spectral data (IR, $^1H$ NMR, $^{13}C$ NMR and Mass).
Rahul Sharma,Arthanareeswaran Karunambigai,Somlee Gupta,Neelakantan Arumugam 경희대학교 융합한의과학연구소 2022 Oriental Pharmacy and Experimental Medicine Vol.22 No.4
Acmella ciliata (HBK) Cass. (basionym: Spilanthes ciliata HBK) is an herb of high medicinal value. Spilanthol, the prime N-alkamide in A. ciliata, is used as an active ingredient in several anti-ageing herbal tonics and in mouth washes. Here we describe quantification of spilanthol, phenolics, flavonoid and antioxidant activity in the methanol extracts prepared from flower, leaf, root and stem of the plant. HPLC of the sample extracts revealed that spilanthol was found to be maximum in flowers (18.44 mg/g), as compared to other parts of the plant as well as several of other Acmella (syn: Spilanthes) species. Estimation of phenolics and flavonoids in the extract by spectrophotometry with their values expressed respectively as equivalence of gallic acid (GAE) and quercetin (QE), revealed that phenolics content was highest in the flower extract (5.58 mg GAE/g), whereas, flavonoid content was found maximum in the leaf extract (31.65 mg QE/g). Antioxidant activity of the extract remained proportional to phenolic content of the extract. Flower extract further showed highest free radical scavenging activity in DPPH and ABTS assays, as compared to the extracts from other parts of the plant. Pearson’s correlation for antioxidant activity with respect to the phenolic and flavonoid content turned out to be positive. To the best of our knowledge this is the first report on quantification of the three secondary metabolites considered here and the antioxidant activity in the methanol extract prepared from different parts of A. cilitata.
Rahul R. Gadkari,Ashutosh Gupta,Uddesh Teke,Atul Awadhiya,Mohammad Shahadat,Wazed Ali,Apurba Das,Ramasamy Alagirusamy 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-
In this study, a novel eco-friendly chitosan-cinnamaldehyde cross-linked nanoparticles (CSN) weresynthesised via a green route and deposited, in alternating combination with sodium tripolyphosphate(TPP), over polyester (PET) nonwoven fabric using layer-by-layer (L-B-L) coating technique. Thesuccessful deposition of a nano-level coating (upto 684.7 nm) of 10.5 bi-layers of CSN and TPP, i.e. (CSN/TPP)10.5, with CSN at the top, was achieved at individualfibre surface as confirmed via scanning electronmicroscopy. Fabric coated with (CSN/TPP)10.5 showed remarkable antibacterial activity against both theGram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, even with a lowconcentration of the nanoparticles (0.1 w/v). Moreover, the coating material possesses very low toxicityas revealed by the cytotoxicity test. The developed fabric could also adsorb metal ions like Pb2+, Cu2+, Fe3+,Ni2+, Zr4+ and Cd2+, etc. from water. The coating was found to be stable in alkaline and neutral pHenvironments. The slight reduction in the pore dimensions, air permeability and tensile strength of fabricafter coating were insignificant with respect to its potential applications in developing health careproducts, medical and health care textiles and dry or wet purification media.