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3. Improved photopyroelectric (PPE) configuration for thermal effusivity investigations of porous solidsCarmen Tripon, Mohanachandran Nair Sindhu Swapna, Nicoleta Cobirzan, Dorota Korte, Robert Gutt, Marcel Bojan, Mladen Franko, Dorin Dadarlat, 2023, original scientific article Keywords: photothermal techniques, photopyroelectric calorimetry, thermal effusivity, porous solids, building materials Published in RUNG: 12.04.2023; Views: 193; Downloads: 14
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5. Influence of P3HT:PCBM Ratio on Thermal and Transport Properties of Bulk Heterojunction Solar CellsDorota Korte, Egon Pavlica, Domen Klancar, Gvido Bratina, Michal Pawlak, Ewa Gondek, Peng Song, Junyan Liu, Beata Beata Derkowska-Zielinska, 2023, original scientific article Keywords: organic bulk-heterojunction solar cells, polymer-fullerene solar cells, photothermal beam
deflection spectrometry, non-radiative recombination, thermal diffusivity, frequency domain methods Published in RUNG: 09.01.2023; Views: 375; Downloads: 13
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9. Time series analysis of duty cycle induced randomness in thermal lens systemSwapna Mohanachandran Nair Sindhu, 2020, original scientific article Abstract: The present work employs time series analysis, a proven powerful mathematical tool, for investigating the complex molecular dynamics of the thermal lens (TL) system induced by the duty cycle (C) variation. For intensity modulation, TL spectroscopy commonly uses optical choppers. The TL formation involves complex molecular dynamics that vary with the input photothermal energy, which is implemented by varying the duty cycle of the chopper. The molecular dynamics
is studied from the fractal dimension (D), phase portrait, sample entropy (S), and Hurst exponent (H) for different duty cycles. The increasing value of C is found to increase D and S, indicating that the system is becoming complex and less deterministic, as evidenced by the phase portrait analysis. The value of H less than 0.5 conforms the evolution of the TL system to more anti-persistent nature with C. The increasing value of C increases the enthalpy of the system that appears as an increase in full width at half maximum of the refractive index profile. Thus the study establishes that the sample entropy and thermodynamic entropy are directly related. Keywords: Time series analysis
Fractal analysis
Photothermal lens spectroscopy
Fractal dimension
Hurst exponent
Sample entropy Published in RUNG: 05.07.2022; Views: 456; Downloads: 0 This document has many files! More... |
10. Thermal diffusivity downscaling of molybdenum oxide thin film through annealing temperature-induced nano-lamelle formation: a photothermal beam deflection studyS. Soumya, Vimal Raj, Mohanachandran Nair Sindhu Swapna, Sankaranarayana Iyer Sankararaman, 2021, original scientific article Abstract: The present work proposes a method of downscaling the thermal diffusivity (α)
of MoO3 thin films through annealing temperature-induced nano-lamelle formation. The
thermal diffusivity modification of the MoO3 films, prepared by the doctor blade method,
is investigated by the sensitive transverse photothermal beam deflection technique. The X-ray diffraction analysis confirms the structural phase transformation from monoclinic to
orthorhombic in the films annealed from 300 to 450 °C. The thermal induced anisotropy of
the film is evident from the variation of the morphology index and texture coefficient. The
field emission scanning electron microscopic analysis unveils the morphology modifications
from blocks to the nano-lamelle structure with layers of average thickness ~ 77 nm. The
thermal diffusivity measurement reveals a 53% reduction upon annealing the film to 450 °C.
The drastic reduction is achieved through the annealing temperature-induced nano-lamelle
formation and the phase transformation from monoclinic to orthorhombic in the MoO3 films. Keywords: thermal diffusivity, molybdenum oxide, thin film, nano-lamelle, photothermal beam deflection Published in RUNG: 04.07.2022; Views: 432; Downloads: 22
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