This paper investigates the wind noise pressure spectra measured by aerodynamically designed devices in turbulent flow. Such measurement probes are often used in acoustic measurements in wind tunnels to reduce the pressure fluctuations generated by the interaction of the devices with the incident flow. When placed in an outdoor turbulent environment however, their performance declines noticeably. It is hypothesized that these devices are measuring the stagnation pressures generated by the cross flow components of the turbulence. Predictions for the cross flow contribution to the stagnation pressure spectra based on measured velocity spectra are developed, and are then compared to the measured pressure spectra in four different probe type devices in windy conditions outdoors. The predictions agree well with the measurements and show that the cross flow contamination coefficient is on the order of 0.5 in outdoor turbulent flows in contrast to the published value of 0.15 for measurements in a turbulent jet indoors.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1121/1.3377049 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
Institute of Exact and Naturals Sciences, Federal University of Pará, 66075-110 Belém, PA, Brazil.
Chalcones are organic substances that have diverse biological activities and exhibit potential for the treatment of various diseases. The properties of these substances depend on the type and position of the functional group attached to their aromatic rings. As a result, in this work the chalcone (2E)-1-(4-hydroxyphenyl)-3-(4-methoxyphenyl)-prop-2-en-1-one (CHO) was investigated by Raman spectroscopy and computational calculations at high pressures with the objective of analyzing its structural stability.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Shunde Innovation School, University of Science and Technology Beijing, Foshan 528399, China.
Mid-infrared spectral analysis has long been recognized as the most accurate noninvasive blood glucose measurement method, yet no practical compact mid-infrared blood glucose sensor has ever passed the accuracy benchmark set by the USA Food and Drug Administration (FDA): to substitute for the finger-pricking glucometers in the market, a new sensor must first show that 95% of their glucose measurements have errors below 15% of these glucometers. Although recent innovative exploitations of the well-established Fourier-transform infrared (FTIR) spectroscopy have reached such FDA accuracy benchmarks, an FTIR spectrometer is too bulky. The advancements of quantum cascade lasers (QCLs) can lead to FTIR spectrometers of reduced size, but compact QCL-based noninvasive blood glucose sensors are not yet available.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland.
In situ X-ray reciprocal space mapping was performed during the interval heating and cooling of InGaN/GaN quantum wells (QWs) grown via metal-organic vapor phase epitaxy (MOVPE). Our detailed in situ X-ray analysis enabled us to track changes in the peak intensities and radial and angular broadenings of the reflection. By simulating the radial diffraction profiles recorded during the thermal cycle treatment, we demonstrate the presence of indium concentration distributions (ICDs) in the different QWs of the heterostructure (1.
View Article and Find Full Text PDFSci Rep
January 2025
Institute of High Pressure Physics, PAS, Warsaw, Poland.
This study addresses the issue of effective carrier injection to quantum wells in laser diode structures. The nitride light emitting structures used in this study were fabricated by Metal-Organic Vapor Phase Epitaxy (MOVPE). We developed three distinct sets of samples, with varying quantum barrier thickness, different QWs indium composition and different position relative to the p- and n-sides of the structure.
View Article and Find Full Text PDFSe Pu
February 2025
CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Chemical modifications are widely used in research fields such as quantitative proteomics and interaction analyses. Chemical-modification targets can be roughly divided into four categories, including those that integrate isotope labels for quantification purposes, probe the structures of proteins through covalent labeling or cross-linking, incorporate labels to improve the ionization or dissociation of characteristic peptides in complex mixtures, and affinity-enrich various poorly abundant protein translational modifications (PTMs). A chemical modification reaction needs to be simple and efficient for use in proteomics analysis, and should be performed without any complicated process for preparing the labeling reagent.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!