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Jasnamol Pezhumkattil Palakkal Aswathi Kaipamangalath Cheriyedath Raj Sankar Manoj R. Varma 《Ceramics International》2018,44(18):22401-22405
The perovskite-type LaFe0.5Ni0.5O3 belonging to the rhombohedral (space group R-3c) crystal structure has been synthesized for which we have identified a magnetic transition at T1 =?8?K corresponding to the minimum observed in the derivative of temperature dependent magnetization. A bifurcation in the ZFC and FC curves is observed below T1 that suggests a frustrated magnetic behavior. The non-zero moment above T1 hints the possibility of the presence of a high-temperature magnetic transition in the material. The resistivity of LaFe0.5Ni0.5O3 evolves as a function of temperature similar to that of a semiconductor. Mott's variable range hopping governs the conduction mechanism of the material. Presence of various anisotropy terms and inhomogeneous magnetic interactions lead to the presence of antiferromagnetic and ferromagnetic interfaces, which eventually causes a magnetic exchange bias and magnetic hysteresis in resistivity. We have also observed direction dependent magnetoresistance in the material. 相似文献
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Nanoporous rice husk derived carbon for gas storage and high performance electrochemical energy storage 总被引:1,自引:0,他引:1
Aswathi Ganesan Ritwika Mukherjee Jyotish Raj Manikoth M. Shaijumon 《Journal of Porous Materials》2014,21(5):839-847
We report on the gas storage behaviour and electrochemical charge storage properties of high surface area activated nanoporous carbon obtained from rice husk through low temperature chemical activation approach. Rice husk derived porous carbon (RHDPC) exhibits varying porous characteristics upon activation at different temperatures and we observed high gas uptake and efficient energy storage properties for nanoporous carbon materials activated even at a moderate activation temperature of 500 °C. Various experimental techniques including Fourier transform-infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy and pore size analyser are employed to characterise the samples. Detailed studies on gas adsorption behaviour of CO2, H2 and CH4 on RHDPCs have been performed at different temperatures using a volumetric gas analyser. High adsorption capacities of ~9.4 mmol g?1 (298 K, 20 bar), 1.8 wt% (77 K, 10 bar) and ~5 mmol g?1 (298 K, 40 bar) were obtained respectively for CO2, H2 and CH4, superior to many other carbon based physical adsorbents reported so far. In addition, these nanoporous carbon materials exhibit good electrochemical performance as supercapacitor electrodes and a maximum specific capacitance of 112 F g?1 has been obtained using aqueous 1 M Na2SO4 as electrolyte. Our studies thus demonstrate that nanoporous carbon with high porosity and surface area, obtained through an efficient approach, can act as effective materials for gas storage and electrochemical energy storage applications. 相似文献
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Madathinal Kunjappan Aswathi Moothetty Padmanabhan Lovely Mathew Prosenjit Saha Roberto Terzano Nandakumar Kalarikkal Tatiana Volova Sabu Thomas 《Polymer Engineering and Science》2019,59(Z1):E435-E445
Through a very facile route, a new class of nanocomposites involving poly(trimethylene terephthalate; PTT) and multiwalled carbon nanotubes (MWCNTs) was developed which was found to be high performance engineering material showing high modulus. Morphological, mechanical, viscoelastic, and thermal properties of the PTT nanocomposites with varying compositions of MWCNT were systematically studied and the results were analyzed. The dynamic mechanical and tensile properties of all the nanocomposites were seen to be enhanced with the addition of MWCNT and the sample containing 2 wt% MWCNT showing a storage modulus as much as 9.4 × 108 GPa. The results were correlated with the morphological features obtained from scanning electron microscopy and transmission electron microscopy. Coefficient of effectiveness, degree of entanglement density, and reinforcement efficiency factor were estimated from the storage modulus values and, in addition, the degree of chain confinement also could be quantified. Furthermore, theoretical modelling was also done on the elastic properties of the composites. The crystallization temperature, glass transition temperature, and percentage crystallinity were estimated for all the nanocomposites and it was found that the sample with 3 wt% MWCNT content exhibited the highest glass transition temperature of 68.2°C. POLYM. ENG. SCI., 59:E435–E445, 2019. © 2018 Society of Plastics Engineers 相似文献
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Bacillus Spores in the Food Industry: A Review on Resistance and Response to Novel Inactivation Technologies 下载免费PDF全文
Aswathi Soni Indrawati Oey Pat Silcock Phil Bremer 《Comprehensive Reviews in Food Science and Food Safety》2016,15(6):1139-1148
The importance and challenges presented by Bacillus spores in the food industry are briefly outlined with a focus on Bacillus cereus. The structure and the mechanism of resistance exhibited by Bacillus spores are described, and the steps involved in their germination are included. Novel technologies, using no or only mild heat treatments, to inactivate Bacillus spores are covered, including ultraviolet radiation, pulsed electric field, and high‐pressure processing, both as stand‐alone techniques or techniques as part of a hurdle approach. 相似文献
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A new “carbon monoxide‐free” synthesis of carboxylate derivatives via carbonylative coupling of aryl bromides with phenols, alcohols, amines and acids in the presence of copper(I) bromide as catalyst and sodium cyanide in a stoichiometric amount has been developed. Its intramolecular version provides for the preparation of lactones (e.g., isochroman‐1‐ones and isobenzfuranones), imides, anhydrides and lactams in excellent yields (73–96%).
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Aswathi Soni Linda M. Samuelsson Simon M. Loveday Tanushree B Gupta 《Comprehensive Reviews in Food Science and Food Safety》2021,20(5):4652-4677
Bioactive compounds in food can have high impacts on human health, such as antioxidant, antithrombotic, antitumor, and anti-inflammatory activities. However, many of them are sensitive to thermal treatments incurred during processing, which can reduce their availability and activity. Milk, including ovine, caprine, bovine, and human is a rich source of bioactive compounds, including immunoglobulins, vitamins, and amino acids. However, processing by various novel thermal and non-thermal technologies has different levels of impacts on these compounds, according to the studies reported in the literature, predominantly in the last 10 years. The reported effect of these technologies either covers microbial inactivation or the bioactive composition; however, there is a lack of comprehensive compilation of studies that compare the effect of these technologies on bioactive compounds in milk (especially, caprine and ovine) to microbial inactivation at similar settings. This research gap makes it challenging to conclude on the specific processing parameters that could be optimized to achieve targets of microbial safety and nutritional quality at the same time. This review covers the effect of a wide range of thermal and non-thermal processing technologies including high-pressure processing, pressure-assisted thermal sterilization, pulsed-electric field treatment, cold plasma, microwave-assisted thermal sterilization, ultra-high-pressure homogenization, ultrasonication, irradiation on the bioactive compounds as well as on microbial inactivation in milk. Although a combination of more than one technology could improve the reduction of bacterial contaminants to meet the required food safety standards and retain bioactive compounds, there is still scope for research on these hurdle approaches to simultaneously achieve food safety and bioactivity targets. 相似文献
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Gopi Kalaiyarasan Karatha Aswathi James Joseph 《International Journal of Hydrogen Energy》2017,42(36):22866-22876
The production of Hydrogen (H2) gas for fuel cell application using electrochemical methods is attracting the attention of the researchers in recent years owing to its high calorific value. Current researchers are enthused to prepare cost effective catalysts from abundant elements in earth crust for the huge production of H2. Recently electrochemical studies are reported based on Metal sulfides and oxides such as MoS2, CoS, WO3 as best catalyst for H2 generation under diverse pH conditions. We focused on preparing nanoporous Nickel Sulfide (NiS) films from Nickel Hexacyanoferrate (NiHCF) nanocubes using electrochemical cycling of the precursor films in Sulfide medium and characterized those using spectroscopy and Microscopy techniques such as FT-IR, Raman spectroscopy, XPS, EDS, XRD, FESEM, AFM, and TEM. The cubic structure of NiHCF gets transformed into NiS cubic skeleton by etching in presence of sulfide ions (S2?). The nanoporous NiS give best results for Hydrogen Evolution Reaction (HER) in the alkali medium. The catalysts were electrochemically modified on glassy carbon surface for electrochemical characterization including Tafel polarization. For comparison, the same procedure was used to prepare other metal sulfides including MnS, FeS, and CoS to compare their catalytic activity towards Hydrogen evolution. Among them, the NiS was shown to be the most efficient electrocatalyst for hydrogen evolution and has shown promise as an alternative to platinum. 相似文献
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Ramanathan Muralidharan Pillaibakkam Bahukudumbi Sindhuja Aswathi Sudalai K. V. Radha 《Korean Journal of Chemical Engineering》2013,30(12):2191-2196
Industrial effluents are major pollution-causing agents for our environment. Our study focuses on utilizing effluents from different industries for efficient production of Polyhydroxybutyrate (PHB). Presence of PHB was identified by Sudan Black staining method. The PHB production parameters for Pseudomonas aeruginosa MTCC 4673 were studied critically, and it was found that glucose with 8.5 mg/L (0.0550 g PHB/g substrate) PHB concentration yielded the highest among the carbon sources used. Peptone with 8.9 mg/L (0.0524 g PHB/g substrate) of PHB concentration, an incubation period of 48 h and at a pH of 7 yielded the optimum results. These studies were compared with those of Alcaligens latus MTCC 2311. Dairy effluents (DE) and tannery effluents (TE) were considered for the best possible substrate, for the production of PHB in an optimized media. The results indicated that the dairy effluents gave a higher yield of PHB. Amongst various dilution levels studied from 10–100% (v/v), 50% (v/v) concentration of the dairy effluent showed maximum PHB productivity of 0.0582 g PHB/g substrate. A comparison of the chemical oxygen demand (COD) and biological oxygen demand (BOD) from the results, showed a significant removal percentage of 78.97% BOD and 53.482% COD, which highlighted the importance of utilizing effluents for PHB production, in order to reduce the risk of toxic effluent discharge. FT-IR analysis was carried out to confirm the presence of PHB. 相似文献
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Aswathi Soni Yash Dixit Marlon M. Reis Gale Brightwell 《Comprehensive Reviews in Food Science and Food Safety》2022,21(4):3717-3745
Hyperspectral imaging (HSI) is a robust and nondestructive method that can detect foreign particles such as microbial, chemical, and physical contamination in food. This review summarizes the work done in the last two decades in this field with a highlight on challenges, risks, and research gaps. Considering the challenges of using HSI on complex matrices like food (e.g., the confounding and masking effects of background signals), application of machine learning and modeling approaches that have been successful in achieving better accuracy as well as increasing the detection limit have also been discussed here. Foodborne microbial contaminants such as bacteria, fungi, viruses, yeast, and protozoa are of interest and concern to food manufacturers due to the potential risk of either food poisoning or food spoilage. Detection of these contaminants using fast and efficient methods would not only prevent outbreaks and recalls but will also increase consumer acceptance and demand for shelf-stable food products. The conventional culture-based methods for microbial detection are time and labor-intensive, whereas hyperspectral imaging (HSI) is robust, nondestructive with minimum sample preparation, and has gained significant attention due to its rapid approach to detection of microbial contaminants. This review is a comprehensive summary of the detection of bacterial, viral, and fungal contaminants in food with detailed emphasis on the specific modeling and datamining approaches used to overcome the specific challenges associated with background and data complexity. 相似文献