11. Blue light emitting diesel soot for photonic applicationsMohanachandran Nair Sindhu Swapna, Sankararaman S, 2018, original scientific article Abstract: The present work is the first report of producing blue light emission from phosphor free and low-cost material—the diesel soot from the internal combustion engines (ICEs). The structural morphology is analyzed by field emission scanning electron microscopy and high-resolution transmission electron microscopy. The optical characterization is done by recording UV–visible spectrum and photoluminescent Spectrum. The CIE plot and the power spectrum for the sample show blue emission. This is further verified by collecting diesel soot from the ICE of different year of make. A visual confirmation of blue emission is obtained by exciting the sample with UV laser. The presence of various allotropic forms of carbon in the sample is identified by x-ray diffraction, Fourier transform infrared and Raman spectroscopic analysis.
Keywords: blue light emitter, diesel soot, photoluminescence, CIE plot
Published in RUNG: 30.06.2022; Views: 1088; Downloads: 0
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12. Camphor soot: A Tunable Light EmitterMohanachandran Nair Sindhu Swapna, SARITHA DEVI H V, Sankararaman S, 2018, original scientific article Abstract: The work in this paper is the first report on the green synthesis of the blue light emitter from waxy, flammable solid collected
from Cinnamomum camphora by controlled combustion for photonic applications. Analysis with field emission scanning
electron microscope and high-resolution transmission electron microscope provides the morphology, whereas the thermo-gravimetric analysis gives the thermal stability of the soot. The optical and structural characterizations are done by recording
UV–Visible, Photoluminescent, and Raman Spectrum. The CIE plot and the power spectrum of the sample show a blue
emission at an excitation of 350 nm at room temperature with a quantum yield of 46.15%. The dependence of luminescent
behavior on temperature and excitation wavelength reveals that the material is a tunable blue emitter. This green synthesis of
the blue light emitter is highly significant, when the world is in search of a simple, phosphor-free, non-toxic, cost-effective
material with good quantum efficiency
Keywords: camphor, soot, blue light emitter
Published in RUNG: 30.06.2022; Views: 996; Downloads: 0
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13. Synthesis and Characterization of Carbon Nano KajalMohanachandran Nair Sindhu Swapna, 2017, short scientific article Abstract: Carbon nanoparticles are of considerable interest today because of their unique physical and biological properties. There are several
methods of preparation of Carbon Nanoparticles (CNP) with high efficacy and low toxicity. In this paper we describe a simple low cost
synthesis of carbon nanoparticle. We present a simple method for the synthesis of carbon nanoparticles from the controlled combustion of
coconut oil and ghee. The antibacterial property of CNP enables its use in kajals. The FESEM image of the sample prepared exhibit carbon
nanoparticles of size less than 50nm
Keywords: Kajal, carbon nanoparticles, soot
Published in RUNG: 30.06.2022; Views: 995; Downloads: 0
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14. Boron‑rich boron carbide from soot : a low-temperature green synthesis approachMohanachandran Nair Sindhu Swapna, H. V. Saritha Devi, Sankaranarayana Iyer Sankararaman, 2020, original scientific article Abstract: Boron carbide is a promising super-hard semiconducting material for refractory applications ranging from the nuclear industry to spacecraft. The present work is the frst report of not only turning futile soot, containing carbon allotropes in varying
composition, into boron-rich boron carbide (BC), but also developing it by a low-cost, low-temperature, and green synthesis
method. The BC synthesised from gingelly oil soot is subjected to structural, morphological, and optical characterisations.
The feld emission scanning electron microscope shows beautiful fower-like morphology, and the thermogravimetric analysis reveals the high-temperature stability of the sample synthesised. The Tauc plot of the sample indicates a 2.38 eV direct
bandgap. The formation of BC and boron-rich carbide evidenced by X-ray difraction studies is confrmed through Raman
and Fourier transform infrared spectroscopic signatures of B–C and C–B–C bonds. The fuorescence, power spectrum, and
CIE analyses carried out suggest the blue light emission for excitation at 350 nm
Keywords: boron carbide, soot, carbon nanoparticle, refractory, allotropes, green synthesis
Published in RUNG: 30.06.2022; Views: 1213; Downloads: 0
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15. Soot effected sample entropy minimization in nanofluid for thermal system design : a thermal lens studyMohanachandran Nair Sindhu Swapna, Vimal Raj, K. Satheesh Kumar, Sankaranarayana Iyer Sankararaman, 2020, original scientific article Abstract: The present work suggests a method of improving the thermal system efficiency, through entropy minimisation,
and unveils the mechanism involved by analysing the molecular/particle dynamics in soot nanofluids (SNFs)
using the time series, power spectrum, and wavelet analyses of the thermal lens signal (TLS). The photothermal
energy deposition in the SNF lowers the refractive index due to the temperature rise. It triggers the particle dynamics that are investigated by segmenting the TLS and analysing the refractive index, phase portrait, fractal dimension (D), Hurst exponent (H), and sample entropy (SampEn). The wavelet analysis gives information about
the relation between the entropy and the frequency components. When the phase portrait analysis reflects the
complex dynamics from region 1 to 2 for all the samples, the SampEn analysis supports it. The decreasing
value of D (from 1.59 of the base fluid to 1.55 and 1.52) and the SampEn (from 1.11 of the base fluid to 0.385
and 0.699) with the incorporation of diesel and camphor soot, indicate its ability to lower the complexity, randomness, and entropy. The increase of SampEn with photothermal energy deposition suggests its relation to
the thermodynamic entropy (S). The lowering of thermal diffusivity value of the base fluid from
1.4 × 10−7 m2/s to 1.1 × 10−7 and 0.5 × 10−7 m2
/s upon diesel and camphor soot incorporation suggests the
heat-trapping and reduced molecular dynamics in heat dissipation.
Keywords: soot, entropy, thermal system, photothermal, time series, nanofluid, fractal
Published in RUNG: 30.06.2022; Views: 1137; Downloads: 0
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16. Morphology and mixing state of aged soot particles at a remote marine free troposphere site : implications for optical propertiesSwarup China, Barbara Scarnato, Robert C. Owen, Bo Zhang, MarianT. Ampadu, Sumit Kumar, Katja Džepina, Michael P. Dziobak, Paulo Fialho, Judith A. Perlinger, 2015, original scientific article Abstract: The radiative properties of soot particles depend on their morphology and mixing state, but their evolution during transport is still elusive. Here we report observations from an electron microscopy analysis of individual particles transported in the free troposphere over long distances to the remote Pico Mountain Observatory in the Azores in the North Atlantic. Approximately 70% of the soot particles were highly compact and of those 26% were thinly coated. Discrete dipole approximation simulations indicate that this compaction results in an increase in soot single scattering albedo by a factor of <= 2.17. The top of the atmosphere direct radiative forcing is typically smaller for highly compact than mass-equivalent lacy soot. The forcing estimated using Mie theory is within 12% of the forcing estimated using the discrete dipole approximation for a high surface albedo, implying that Mie calculations may provide a reasonable approximation for compact soot above remote marine clouds.
Keywords: atmospheric aerosol, soot, long-range transport, free troposphere, single scattering albedo
Published in RUNG: 11.04.2021; Views: 2049; Downloads: 0
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