The frequency spectra of the entropy and kinetic energy along with the power spectrum of the thermal flux are computed from direct numerical simulations for turbulent Rayleigh-Bénard convection with uniform rotation about a vertical axis in low-Prandtl-number fluids (Pr<0.6). Simulations are done for convective Rossby numbers Ro≥0.2. The temporal fluctuations of these global quantities show two scaling regimes: (i) ω(-2) at higher frequencies for all values of Ro and (ii) ω(-γ1) at intermediate frequencies with γ1≈4 for Ro>1, while 4<γ1<6.6 for 0.2≤Ro<1.
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http://dx.doi.org/10.1103/PhysRevE.90.041004 | DOI Listing |
Anal Chem
January 2025
School of Mechanical and Robotics Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
Electrochemical impedance spectroscopy has great potential for laboratory blood tests. The overall aim of this study is to develop a microfluidic sensor for determining the physical properties and hematological parameters of blood based on its dielectric spectra. Impedance was measured in flowing blood to prevent aggregation and sedimentation at frequencies between 40 Hz and 110 MHz.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer-Straße 66, 38106 Braunschweig, Germany.
A novel piezoresistive cantilever microprobe (PCM) with an integrated electrothermal or piezoelectric actuator has been designed to replace current commercial PCMs, which require external actuators to perform contact-resonance imaging (CRI) of workpieces and avoid unwanted "forest of peaks" observed at large travel speed in the millimeter-per-second range. Initially, a PCM with integrated resistors for electrothermal actuation (ETA) was designed, built, and tested. Here, the ETA can be performed with a piezoresistive Wheatstone bridge, which converts mechanical strain into electrical signals by boron diffusion in order to simplify the production process.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, D-38106 Braunschweig, Germany.
A new method for the precise semiempirical determination of the basic parameters (structural parameters and parameters of the intramolecular potential energy surface, PES) of a molecule on the basis of highly accurate experimental data from the microwave and submillimeter-wave regions is suggested. The options and advantages of this method in comparison with the other methods of molecular PES determination are discussed using a diatomic molecule as an appropriate illustration. The HCl molecule is exploited as a suitable example.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
Physics Department, College of Science, King Faisal University, Al Ahsa, 31982, Saudi Arabia. Electronic address:
To consistently determine the anomalous characteristics of phthalic acid crystal (PAC) derivatives, we performed quantum dynamics simulations of the infrared spectral density of the h-PAC and d-PAC isotopomers that show up in the H/D isotopic frequency domain at two different temperatures viz. 77 and 298 K. A theoretical framework explaining the dynamical cooperative interactions within the hydrogen bonds (HBs) in the PAC crystals across a simulation of IR spectral density of the stretching band was developed.
View Article and Find Full Text PDFUltrason Sonochem
January 2025
School of Engineering Computing and Mathematics, Oxford Brookes University, Oxford, UK; Department of Materials, University of Oxford, Oxford, UK.
This study experimentally investigates the role of cavitation-induced shock waves in initiating and destabilizing capillary (surface) waves on a droplet surface, preceding atomization. Acoustic emissions and interfacial wave dynamics were simultaneously monitored in droplets of different liquids (water, isopropyl alcohol and glycerol), using a calibrated fiber-optic hydrophone and high-speed imaging. Spectral analysis of the hydrophone data revealed distinct subharmonic frequency peaks in the acoustic spectrum correlated with the wavelength of capillary waves, which were optically captured during the onset of atomization from the repetitive imploding bubbles.
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