5. Miscellaneous Publications
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Item Advanced two-dimensional heterojunction photocatalysts of stoichiometric and non-stoichiometric bismuth oxyhalides with graphitic carbon nitride for sustainable energy and environmental applications(2021) Sridharan K.; Shenoy S.; Kumar S.G.; Terashima C.; Fujishima A.; Pitchaimuthu S.Semiconductor-based photocatalysis has been identified as an encouraging approach for solving the two main challenging problems, viz., remedying our polluted environment and the generation of sustainable chemical energy. Stoichiometric and non-stoichiometric bismuth oxyhalides (BiOX and BixOyXz where X = Cl, Br, and I) are a relatively new class of semiconductors that have attracted considerable interest for photocatalysis applications due to attributes, viz., high stability, suitable band structure, modifiable energy bandgap and two-dimensional layered structure capable of generating an internal electric field. Recently, the construction of heterojunction photocatalysts, especially 2D/2D systems, has convincingly drawn momentous attention practicably owing to the productive influence of having two dissimilar layered semiconductors in face-to-face contact with each other. This review has systematically summarized the recent progress on the 2D/2D heterojunction constructed between BiOX/BixOyXz with graphitic carbon nitride (g-C3N4). The band structure of individual components, various fabrication methods, different strategies developed for improving the photocatalytic performance and their applications in the degradation of various organic contaminants, hydrogen (H2) evolution, carbon dioxide (CO2) reduction, nitrogen (N2) fixation and the organic synthesis of clean chemicals are summarized. The perspectives and plausible opportunities for developing high performance BiOX/BixOyXz-g-C3N4 heterojunction photocatalysts are also discussed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Item Uncertainties in predicting impacts of climate change on hydrology in basin scale: a review(2020) Jose D.M.; Dwarakish G.S.The sensitivity of the hydrological system to climate change and the role of hydrological systems in the environment have motivated researchers to study the impacts of climate change on hydrology. Modelling the hydrological impacts of climate change is generally done in various stages and has uncertainty associated with each of them. These include scenario uncertainty in climate scenario selection, model uncertainty in climate simulation by global climatic models (GCMs), uncertainties while downscaling GCMs, biases in downscaled data, erroneous input to the hydrological model, and uncertainty in the structure and parameterisation of the hydrological model. The present paper aims at reviewing the uncertainties involved at each stage of climate change impact assessment of hydrology. In the near future, climate scenario uncertainties would be smaller than those associated with the choice of GCMs. Multi-model ensemble approach takes better account of uncertainties involved with GCMs. Moreover, considering a range of possible climate scenarios is recommended than using a single best or average case climate scenario. GCMs shall be downscaled by statistical or dynamical methods (regional climatic models (RCMs)) before using them for regional studies. Bias correction methods can considerably improve the RCM simulations. Evaluation of model performance is recommended for regional-scale studies for the preparation of adaptation strategies. Taking into account the uncertainties associated with climate impact studies can help formulate effective adaptation strategies. © 2020, Saudi Society for Geosciences.Item Use of antioxidants for enhancing oxidative stability of bulk edible oils: a review(2021) Mishra S.K.; Belur P.D.; Iyyaswami R.Edible oils industry is using synthetic and natural antioxidants to enhance the oxidative stability of bulk edible oils. Due to safety concerns of BHA, BHT and TBHQ, there is an ongoing effort to find an effective and safe replacement. Finding a safe antioxidant or its synergistic mixture, which delays, retard or prevent the oxidation of bulk oil without changing the colour or flavour upon addition is a challenge. In this review, a brief account of chemical basis of oxidative deterioration of the stored oil is given. The effectiveness of most widely experimented antioxidants such as tocopherols, carotenoids, ascorbic acid and its derivatives, lignan compounds, flavonoids, polyphenols and phenolic acids in various edible oils have been reviewed. Further, the synergistic and antagonistic combination of these antioxidants in controlling oxidative degradation of edible oils has been discussed. © 2020 Institute of Food, Science and Technology (IFSTTF)Item Catalytic synthesis of renewable p-xylene from biomass-derived 2,5-dimethylfuran: a mini review(2020) Dutta, Saikat; Bhat N.S.In this work, the renewable synthesis of p-xylene (PX) from biomass-derived carbohydrates has been reviewed. PX is a crucial chemical feedstock and an essential starting material of polyethylene terephthalate (PET). PX can be produced selectively by the Diels-Alder reaction between ethylene and 2,5-dimethylfuran (DMF) followed by catalytic dehydration of the oxanorbornene adduct. DMF is primarily produced by the catalytic hydrogenation of 5-(hydroxymethyl)furfural (HMF), a furanic intermediate produced by the acid-catalyzed hydrolysis/dehydration of biomass-derived hexoses. With ethylene being sourced by dehydrating bioethanol, PET can be made biorenewable in its entirety. The atom economy and carbon efficiency of converting glucose into PX have been calculated. The existing literature (both theoretical and experimental) on the catalytic production of PX from DMF and ethylene are summarized, and future directions on this research have been proposed. The effect of Brønsted and Lewis acidity, porosity, and surface area of the heterogeneous catalysts on the selectivity and yield of PX have been highlighted. In addition, the techno-economic analysis of renewable PET, its future prospects based on the petroleum market, and the possibility of a circular economy of PET using chemical and enzymatic recycling strategies have been discussed. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Item Anomalies in the CMB from a cosmic bounce(2021) Agullo I.; Kranas D.; Sreenath V.We explore a model of the early universe in which the inflationary epoch is preceded by a cosmic bounce, and argue that this scenario provides a common origin to several of the anomalous features that have been observed at large angular scales in the cosmic microwave background (CMB). More concretely, we show that a power suppression, a dipolar asymmetry, and a preference for odd-parity correlations, with amplitude and scale dependence in consonance with observations, are expected from this scenario. The model also alleviates the tension in the lensing amplitude. These signals originate from the indirect effect that non-Gaussian correlations between CMB modes and super-horizon wavelengths induce in the power spectrum. We follow a phenomenological approach, restricted to a family of bouncing models, and complement our analysis by pointing out to well established theories where our ideas are materialized. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.Item Item Comprehensive review of IDMs in DG systems(2019) Manikonda S.K.G.; Gaonkar D.N.Distributed generation (DG) offers solution to the ever increasing energy needs by generating energy at the consumer end, in most cases, by means of renewable energy sources. Islanding detection is an important aspect of interconnecting a DG to the utility. This study presents comprehensive review of various islanding detection techniques along with their relative advantages and disadvantages. A broad classification of islanding detection methods (IDMs) is laid out as classical methods, signal processing (SP)-based methods, and computational intelligence-based methods with a focus on SP-based methods and computational intelligence-based methods. The evolution of SP techniques used for islanding detection is presented along with the merits and shortcomings of each technique. Furthermore, the advent of computational intelligence methods based IDMs are discussed along with their merits and demerits. An insight into various islanding methods based on quantitative measures of performance indices such as detection time, detection accuracy, and efficiency are tabulated and presented. Finally, the prospective direction of research for IDMs is also presented. © 2019 Institution of Engineering and Technology. All Rights Reserved.Item Recent advances in the preparation of levulinic esters from biomass-derived furanic and levulinic chemical platforms using heteropoly acid (HPA) catalysts(2021) Bhat N.S.; Mal S.S.; Dutta, SaikatThe esters of biomass-derived levulinic acid (LA) have several potential applications, including cleaner-burning fuel additive, green solvent, fragrance ingredient, and a renewable chemical intermediate for downstream value addition. The levulinic esters (LEs) can be prepared by the acid-catalyzed alcoholysis of the biomass-derived furanic and levulinic chemical platforms such as LA, furfuryl alcohol (FAL), 5-(hydroxymethyl)furfural (HMF), and angelica lactone (AGL). The acid-catalyzed deconstruction of carbohydrates in an alcoholic medium affords the one-pot preparation of LEs. Choosing the right catalyst is of paramount importance for synthesizing LEs from both the economic and environmental perspectives. In this regard, heteropoly acids (HPAs), a class of polyoxometalates (POMs) bearing protons as the counter cation, have found widespread applications as acid catalysts in various organic transformations. HPAs are blessed with conducive properties such as controlled Brønsted and Lewis acidity, high thermal stability, robust structural features, non-toxic nature, tunable solubility, and less corrosiveness. Over the past several years, HPAs have found extensive applications as efficient and environment-friendly catalysts in biorefinery operations, including the synthesis of LEs. At this juncture, it is imperative to ascertain the achievements in this field to date and re-evaluate the challenges. This review attempts to provide up-to-date information about the preparation of LEs using HPA-based catalysts, critically analyze the literature cited, draw conclusions, and propose future prospects. © 2021 Elsevier B.V.Item Structure-property-function relationship of fluorescent conjugated microporous polymers(2021) Bai M.G.M.; Babu H.V.; Lakshmi V.; Rao M.R.Porous organic polymers (POPs) consisting of open interconnected pores offer a broad and vast accessible surface area, and thus have been explored extensively in both academia and industry for numerous applications including heterogeneous catalysis, gas separation, gas adsorption/storage, and ion exchange. Introducing the benefits of microporous polymers into the extended π-conjugated organic polymer gives rise to novel materials, namely, conjugated microporous polymers (CMPs), which endow even more intriguing properties/applications, especially in optoelectronics, energy storage, and sensors. In particular, within the domain of CMPs, luminescent CMPs enjoy the advantage of possessing aggregation-induced emission (AIE) and long-range exciton migration accompanied by the intrinsic properties such as microporosity and high surface area. The significant host-guest interactions and fast analyte diffusion facilitated by the microporous environment along with the efficient exciton migration through the polymer network will be fundamental for fast and highly sensitive chemical sensing. The unique structural features in conjunction with the selective properties and encouraging applications of the fluorescent CMPs have triggered a great deal of interest, which have led to rapid progress in the development of structurally diverse fluorescent CMPs. In this review, we present a comprehensive summary of all the advances in the development of fluorescent CMPs based on tetraphenyl ethene (TPE), phenylene, and polycyclic aromatic hydrocarbons (PAHs) and boron- A nd nitrogen-based π-systems and their emerging applications in numerous fields as well as our perspectives on future research. This journal is © the Partner Organisations.Item Recent progress in in vivo studies and clinical applications of magnesium based biodegradable implants – A review(2020) Sekar P.; S N.; Desai V.Biodegradable magnesium has regained great attention due to its ability to temporarily offer mechanical strength and degrade completely once the injured pathological tissue is healed. A few clinical applications of Mg-based implants were reported in the last century. However, the knowledge and experience is being gained continuously by studying the host response and degradation behavior of Mg implant in animal models and clinical trials. This led to the development of commercial products emerging from Europe and Asia very recently. The potential of Mg implants in repairing fractures at upper and lower limb of large, small animal models and humans is compared and discussed in detail. In addition the possible future Mg implants that might treat problems concerning to urology and gynecology are reviewed. © 2020