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3. Eco-conscious nanofluids : exploring heat transfer performance with graphitic carbon nitride nanoparticlesVijayakumar Gokul, Mohanachandran Nair Sindhu Swapna, Sankaranarayana Iyer Sankararaman, 2023, original scientific article Abstract: Abstract
The work explores the heat transfer capabilities of semiconducting graphitic carbon nitride (g-C3N4) nanofluids. Also, it presents a sustainable and eco-friendly method for synthesizing g-C3N4 nanoparticles using commercially available rice flour as a natural carbon precursor through hydrothermal treatment. The synthesized sample subjected to various characterizations, including analysis of their structure, morphology, thermal properties, and optical properties. The optical bandgap (2.66 eV) is deduced through Tauc plot analysis and reveals the semiconducting nature of the sample. The formation of g-C3N4 is confirmed by various spectroscopic techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), and Raman spectroscopy. Thermogravimetric analysis (TGA) demonstrates the nanoparticles’ excellent thermal stability up to 550 °C, indicating potential applications in heat transfer fluids. The investigation of concentration-dependent thermal diffusivity variation using the sensitive mode mismatched dual beam thermal lens technique highlights the potential of g-C3N4 semiconductor nanofluid as an organic and metal-free additive in industry-demanding coolant applications.
Keywords: thermal lens, nanofluids
Published in RUNG: 05.01.2024; Views: 467; Downloads: 4
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7. Accuracy of measurements of thermophysical parameters by dual-beam thermal-lens spectrometryVladislav R. Khabibullin, Mladen Franko, Mikhail A. Proskurnin, 2023, original scientific article Abstract: Thermal-lens spectrometry is a sensitive technique for determination of physicochemical
properties and thermophysical parameters of various materials including heterogeneous systems
and nanoparticles. In this paper, we consider the issues of the correctness (trueness) of measurements
of the characteristic time of the thermal-lens effect and, thus, of the thermal diffusivity determined
by dual-beam mode-mismatching thermal lensing. As sources of systematic errors, major factors—
radiation sources, sample-cell and detector parameters, and general measurement parameters—are
considered using several configurations of the thermal-lens setups, and their contributions are
quantified or estimated. Furthermore, with aqueous ferroin and Sudan I in ethanol as inert colorants,
the effects of the intermolecular distance of the absorbing substance on the correctness of finding the
thermophysical parameters are considered. The recommendations for checking the operation of the
thermal-lens setup to ensure the maximum accuracy are given. The results obtained help reducing
the impact of each investigated factor on the value of systematic error and correctly measure the
thermophysical parameters using thermal-lens spectrometry.
Keywords: thermal-lens spectrometry, accuracy, trueness, mode-mismatched schematic, measurements of thermal diffusivity
Published in RUNG: 20.01.2023; Views: 1128; Downloads: 13
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8. Reflecting the quality degradation of engine oil by the thermal diffusivity : radiative and nonradiative analysesVijayakumar Gokul, Mohanachandran Nair Sindhu Swapna, Dorota Korte, Sankaranarayana Iyer Sankararaman, 2023, original scientific article Keywords: engine oil, thermal diffusivity, thermal lens technique, oil degradation, quality monitoring
Published in RUNG: 12.01.2023; Views: 991; Downloads: 19
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9. Recent progress and applications of thermal lens spectrometry and photothermal beam deflection techniques in environmental sensingMladen Franko, Leja Goljat, Mingqiang Liu, Hanna Budasheva, Mojca Žorž, Dorota Korte, 2023, original scientific article Abstract: This paper presents recent development and applications of thermal lens microscopy (TLM) and beam deflection spectrometry (BDS) for the analysis of water samples and sea ice. Coupling of TLM detection to a microfluidic system for flow injection analysis (µFIA) enables the detection of microcystin-LR in waters with a four samples/min throughput (in triplicate injections) and provides an LOD of 0.08 µg/L which is 12-times lower than the MCL for microcystin-LR in water. µFIA-TLM was also applied for the determination of total Fe and Fe(II) in 3 µL samples of synthetic cloudwater.
The LODs were found to be 100 nM for Fe(II) and 70 nM for total Fe. The application of µFIA-TLM for the determination of ammonium in water resulted in an LOD of 2.3 µM for injection of a 5 µL sample and TLM detection in a 100 µm deep microfluidic channel. For the determination of iron
species in sea ice, the BDS was coupled to a diffusive gradient in the thin film technique (DGT). The 2D distribution of Fe(II) and total Fe on DGT gels provided by the BDS (LOD of 50 nM) reflected the distribution of Fe species in sea ice put in contact with DGT gels.
Keywords: thermal lens microscopy, beam deflection spectrometry, microfluidic system, microcystin-LR detection, iron species determination, ammonium detection
Published in RUNG: 03.01.2023; Views: 1252; Downloads: 24
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