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1.
Tuning the dynamic thermal parameters of nanocarbon ionanofluids : a photopyroelectric study
Mohanachandran Nair Sindhu Swapna, Carmen Tripon, Alexandra Farcas, Dorin Dadarlat, Dorota Korte, Sankaranarayana Iyer Sankararaman, 2024, original scientific article

Abstract: The present work delineates the tailoring of the thermal effusivity and diffusivity of the novel class of heat transfer fluids—ionanofluids—by the incorporation of nanocarbons like diesel soot (DS), camphor soot (CS), carbon nanotubes (CN), and graphene (GR). When the thermal diffusivity delivers information on the thermal energy propagation, the thermal effusivity concerns the energy exchange at the interface, enabling energy-efficient thermal system design. The nanocarbons are subjected to morphological characterisation by field emission scanning electron microscopy. Fourier-transform infrared and Raman spectroscopic analyses confirm functional groups and vibrational bands. The microcrystalline size and graphiticity are also understood from the Raman spectrum. Ionanofluids prepared by dispersing nanocarbons into an ionic liquid base 1-Butyl-3-methylimidazolium methyl sulfate (BMMS) are analysed by nondestructive photopyroelectric calorimetry (PPE). The PPE analysis of ionanofluids demonstrates that nanocarbons influence thermal parameters in the base fluid, with soot ionanofluids exhibiting increased thermal effusivity and diffusivity due to their various carbon allotropic composition. This study underscores the importance of selecting the appropriate carbon allotrope for tailoring ionanofluids’ thermal properties, providing insights into manipulating these properties for enhanced performance across various industrial applications.
Keywords: photopyroelectric, ionanofluid, soot, graphene, thermal diffusivity
Published in RUNG: 06.05.2024; Views: 226; Downloads: 3
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Soot cat
Mohanachandran Nair Sindhu Swapna, 2019, artistic work

Keywords: soot, painting
Published in RUNG: 30.08.2022; Views: 1101; Downloads: 0
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5.
Carbon nanoparticles assisted energy transport mechanism in leaves: A thermal lens study
Mohanachandran Nair Sindhu Swapna, 2019, original scientific article

Abstract: In the world of increasing population and pollution due to carbon emissions, the research for effective utilization of futile diesel soot for fruitful applications has become a necessity for a sustainable development. The contribution to pollution from vehicles and industries due to the aging of engines has caused a crisis. Carbon nanoparticles (CNPs) have been the subject of interest because of their good physical, chemical, and biological properties. The present work investigates the role of CNPs produced by internal combustion engines on the energy transport mechanism among leaf pigments using the sensitive and nondestructive single beam thermal lens technique. The studies reveal the absorption changes by various chlorophyll pigments with the concentration of CNPs sprayed on the leaves. Though for low concentrations CNPs lower the photon absorbance by chlorophyll pigments, the effect gets reversed at higher concentrations. The variation of thermal diffusivity with CNP concentration and its role in the energy transport mechanism among chlorophyll pigments are also studied. It is found that CNP concentrations of 625-2500mg/l are good for better intra-pigment energy transport leading to increased rate of photosynthesis and plant yield and thereby helping in attaining food security. The variation of CNP assisted energy transport among leaf pigments on the production of nicotinamide adenine dinucleotide phosphate (NADPH) and carbohydrates is also studied with ultraviolet (UV) and near-infrared (NIR) spectroscopy.
Keywords: carbon nanoparticle, soot, energy transport, thermal lens, photosynthesis
Published in RUNG: 05.07.2022; Views: 1239; Downloads: 0
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6.
Soot as a precursor for the low temperature synthesis of organometallic sodium carbide
Mohanachandran Nair Sindhu Swapna, SARITHA DEVI H V, Sankararaman S, 2019, original scientific article

Abstract: The carbonaceous soot finds a wide range of applications in many fields due to the richness of various allotropes of carbon. The present work explores the possibility of least investigated sodium carbide (Na2C2) as a potential semiconducting material for photonic applications. The soot, formed by the incomplete combustion of gingelly oil is taken as the carbon precursor for the low-temperature synthesis of the industrially significant organometallic Na2C2. The morphological modifications are analyzed using High-Resolution Transmission Electron Microscope and elemental study is carried out by Energy Dispersive Spectroscopy and x-ray dot mapping. The formation of Na2C2 is primarily identified from x-ray powder diffraction pattern and further confirmed by other structural and thermal analysis techniques such as Fourier Transform Infrared, Raman spectroscopy, and Thermogravimetry. The region of optical absorption, bandgap, as well as its emission properties are studied by recording the Ultraviolet-Visible and Photoluminescence spectrum. The Tauc plot analysis suggests its semiconducting nature with direct bandgap energy of 2.08 eV. The analysis with the help of CIE, and power spectrum reveal a prominent blue emission around 440 nm irrespective of excitation in the UV region. Thus, the major highlights of this work lie in two factors- firstly, the effective utilization of the soot and secondly, easier low-temperature and cost-effective synthesis of semiconducting Na2C2 for photonic applications.
Keywords: carbonaceous soot, sodium carbide, photonic applications
Published in RUNG: 05.07.2022; Views: 1324; Downloads: 0
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7.
Allotropic transformation instigated thermal diffusivity of soot nanofluid: Thermal lens study
Mohanachandran Nair Sindhu Swapna, RAJ VIMAL, Sankararaman S, 2019, original scientific article

Abstract: This paper employs the sensitive single-beam thermal lens technique for analyzing the thermal behavior of gasoline soot containing allotropes of carbon by preparing its nanofluid (NF). The soot, annealed at different temperatures up to 400 ○C (the samples), used for preparing the NF, is found to enhance the thermal diffusivity (α) up to 95% without changing the solid volume fraction, suggesting its possible use in coolants. The thermal induced modifications are understood from the field emission scanning electron microscopic, X-ray diffraction (XRD),thermogravimetric, and Raman spectroscopic analyses. The variation of α of the sample is found to exhibit similar variations observed in XRD and Raman spectroscopic analyses. The study stresses the significance of the optimum temperature (300 ○C) for the soot NF above which morphological and structural modifications may lead to thermal energy trapping rather than dissipation or cooling.
Keywords: petrol soot, thermal lens, thermal diffusivity
Published in RUNG: 04.07.2022; Views: 1274; Downloads: 0
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8.
Tuning the thermal diffusivity of the seed matter for enhanced biosynthesis: A thermal lens study
Mohanachandran Nair Sindhu Swapna, Sankararaman S, 2020, original scientific article

Abstract: The thermodynamics of the seed matter after imbibition is highly significant as the growth and germination involve complex biochemical exergonic process. The germination of seed and compositional variation of the seed matter has always been a fascinating field of research. The present work unveils the thermodynamics associated with the changing thermal diffusivity of the seed matter through the green technology-based single-beam thermal lens technique. Investigations are carried out in Vigna radiata seeds, germinating in media with and without carbon allotropes, through various spectroscopic techniques. The morphology of the soot and carbon allotropes is understood from the field emission scanning electron microscope images. The thermal lens study throws light into the energy trapping nature of the seed matter of the seed growing in carbon allotropic media which facilitates biosynthesis. The observed increased rate of growth of the seed is substantiated through the ultraviolet–visible–near-infrared (NIR), Fourier transform infrared, and photoluminescence (PL) spectroscopic analyses. The NIR and PL studies also reveal the formation of chlorophyll molecule during germination. Thus, the study suggests a mechanism for tuning the thermal diffusivity of the seed matter as to trap the biochemical energy to facilitate the further biosynthesis and thereby to enhance the growth rate.
Keywords: seed matter, thermal diffusivity, thermal lens, carbon nanoparticle, soot
Published in RUNG: 04.07.2022; Views: 1294; Downloads: 0
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9.
The efflorescent carbon allotropes: Fractality preserved blooming through alkali treatment and exfoliation
Mohanachandran Nair Sindhu Swapna, Sankararaman S, 2020, original scientific article

Abstract: The work reported in the paper elucidates morphological modification induced nanoart and surface area enhancement of graphite, graphene, and soot containing carbon allotropes through ultrasonication and alkali-treatment. The field emission scanning electron microscopic (FESEM) analysis of the samples before and after exfoliation reveals the formation of brilliant flower-like structures from spindle-like basic units due to Ostwald ripening. The x-ray diffraction analysis of the samples gives information about structural composition. The fractal analysis of the FESEM images indicates a multifractal structure with the dimensions—box-counting dimension D0 (1.72), information dimension D1 (1.66), and correlation dimension D2 (1.63)—preserved upon exfoliation. The process of ultra-sonication assisted liquid phase exfoliation resembles blooming as if the carbon allotropes are efflorescent.
Keywords: carbon allotropes, fractal dimension, soot, fractality, alkali treatment, exfoliation
Published in RUNG: 04.07.2022; Views: 1329; Downloads: 0
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10.
Fractal and spectroscopic analysis of soot from internal combustion engines
Mohanachandran Nair Sindhu Swapna, SARITHA DEVI H V, RAJ VIMAL, Sankararaman S, 2018, original scientific article

Abstract: Today diesel engines are used worldwide for various applications and very importantly in transportation. Hydrocarbons are the most widespread precursors among carbon sources employed in the production of carbon nanotubes (CNTs). The aging of internal combustion engine is an important parameter in deciding the carbon emission and particulate matter due to incomplete combustion of fuel. In the present work, an attempt has been made for the effective utilization of the aged engines for potential applicationapplications in fuel cells and nanoelectronics. To analyze the impact of aging, the particulate matter rich in carbon content areis collected from diesel engines of different ages. The soot with CNTs is purified by the liquid phase oxidation method and analyzed by Field Emission Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, Energy Dispersive Spectroscopy, UV-Visible spectroscopy, Raman spectroscopy and Thermogravimetric analysis. The SEM image contains self-similar patterns probing fractal analysis. The fractal dimensions of the samples are determined by the box counting method. We could find a greater amount of single-walled carbon nanotubes (SWCNTs) in the particulate matter emitted by aged diesel engines and thereby giving information about the combustion efficiency of the engine. The SWCNT rich sample finds a wide range of applications in nanoelectronics and thereby pointing a potential use of these aged engines.
Keywords: Fractals, internal combustion engine, efficiency, soot, carbon nanoparticle
Published in RUNG: 30.06.2022; Views: 1320; Downloads: 0
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