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1.
Organometallic sodium carbide for heat transfer applications: A thermal lens study
SANKARARAMAN S, SWAPNA MOHANACHANDRAN NAIR SINDHU, 2020, original scientific article

Abstract: The search for excellent heat transfer fuids necessitates the development of novel nanofuids. The paper is the frst report revealing the potential of sodium carbide (Na2C2) nanoparticle for heat transfer and thermal shielding applications. For this, Na2C2 is prepared from the porous carbon matrix of Aloe vera leaves by hydrothermal method. The morphological changes on hydrothermal treatment and the thermal stability are analyzed by Field Emission Scanning Electron Microscopy and Thermogravimetry. The X-ray difraction analysis reveals the formation of sodium carbide, which is confrmed by Fourier transform infrared, Ultraviolet–Visible–Near Infrared, and Raman spectroscopic analyses. The spectroscopic study of the sample synthesized shows indirect bandgap energy of 1.58 eV. The thermal difusivity of Na2C2 nanofuid, determined by the single-beam thermal lens technique, exhibited 87 % enhancement for the base fuid, suggesting its potential in heat transfer applications.
Found in: ključnih besedah
Keywords: Aloe vera, Heat transfer, Organometallic, Sodium carbide, Thermal lens
Published: 04.07.2022; Views: 61; Downloads: 0
.pdf Fulltext (1,75 MB)

2.
Soot as a precursor for the low temperature synthesis of organometallic sodium carbide
SANKARARAMAN S, SARITHA DEVI H V, SWAPNA MOHANACHANDRAN NAIR SINDHU, 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.
Found in: ključnih besedah
Keywords: carbonaceous soot, sodium carbide, photonic applications
Published: 05.07.2022; Views: 94; Downloads: 0
.pdf Fulltext (1,33 MB)

3.
Fluorescent emission from a natural carbon matrix incorporating sodium
SWAPNA MOHANACHANDRAN NAIR SINDHU, 2019, original scientific article

Abstract: The process of functionalization of metals in natural carbon matrices has become an important area of research due to its improved properties and applications. Carbon materials possessing photoluminescence (PL) properties find a wide range of applications in photonics. Among the various carbon materials available in nature, cellulose has critical importance since it is the most abundant and wide-spread biopolymer on Earth, and also, the important component in plants’ skeleton. In the present work, the functionalized carbonaceous material is prepared by the hydrothermal treatment of natural cellulosic source Aloe Vera and the metallic element sodium is properly incorporated into it by adding sodium borohydride to observe the fluorescence emission changes. The incorporation of metal ions in the carbon matrix leads to structural modifications and properties as evidenced by field emission scanning electron microscopy, Energy dispersive spectroscopy, X-ray dot mapping, X-ray Photoelectron spectroscopy, and X-ray diffraction analysis. The optical emission characteristics are studied using Photoluminescence spectroscopy, CIE plot, power spectrum, color purity, and quantum yield. The excitation wavelength dependent photoluminescence emission mechanism shown by the carbon–metal incorporated products obtained from the cellulosic raw materials makes them suitable for biomedical and biosensing applications because of the non-toxic and eco-friendly nature.
Found in: ključnih besedah
Summary of found: ...Fluorescent emission, sodium carbide, cellulose, carbon matrix...
Keywords: Fluorescent emission, sodium carbide, cellulose, carbon matrix
Published: 30.06.2022; Views: 110; Downloads: 0
.pdf Fulltext (3,09 MB)

4.
Natural precursor based hydrothermal synthesis of sodium carbide for reactor applications
SWAPNA MOHANACHANDRAN NAIR SINDHU, 2017, original scientific article

Abstract: Carbides are a class of materials with high mechanical strength and refractory nature which finds a wide range of applications in industries and nuclear reactors. The existing synthesis methods of all types of carbides have problems in terms of use of toxic chemical precursors, high-cost, etc. Sodium carbide (Na2C2) which is an alkali metal carbide is the least explored one and also that there is no report of low-cost and low-temperature synthesis of sodium carbide using the eco-friendly, easily available natural precursors. In the present work, we report a simple low-cost, non-toxic hydrothermal synthesis of refractory sodium carbide using the natural precursor—Pandanus. The formation of sodium carbide along with boron carbide is evidenced by the structural and morphological characterizations. The sample thus synthesized is subjected to field emission scanning electron microscopy (FESEM), x-ray powder diffraction (XRD), ultraviolet (UV)—visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman, and photoluminescent (PL) spectroscopic techniques.
Found in: ključnih besedah
Keywords: sodium carbide, pandanus, hydrothermal synthesis, porous materials
Published: 30.06.2022; Views: 117; Downloads: 0
.pdf Fulltext (2,57 MB)

5.
Tailoring the morphology through alkali treatment
H. V. Saritha Devi, Mohanachandran Nair Sindhu Swapna, Sankaranarayana Iyer Sankararaman, 2020, original scientific article

Found in: ključnih besedah
Summary of found: ...Liquid-phase exfoliation, boron carbide, morphology tuning, sodium hydroxide, refluxion, bleaching...
Keywords: Liquid-phase exfoliation, boron carbide, morphology tuning, sodium hydroxide, refluxion, bleaching
Published: 05.07.2022; Views: 94; Downloads: 0
.pdf Fulltext (2,02 MB)

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