We investigate the superfluid properties of a dipolar Bose-Einstein condensate (BEC) in a fully three-dimensional trap. Specifically, we estimate a superfluid critical velocity for this system by applying the Landau criterion to its discrete quasiparticle spectrum. We test this critical velocity by direct numerical simulation of condensate depletion as a blue-detuned laser moves through the condensate. In both cases, the presence of the roton in the spectrum serves to lower the critical velocity beyond a critical particle number. Since the shape of the dispersion, and hence the roton minimum, is tunable as a function of particle number, we thereby propose an experiment that can simultaneously measure the Landau critical velocity of a dipolar BEC and demonstrate the presence of the roton in this system.
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http://dx.doi.org/10.1103/PhysRevLett.104.094501 | DOI Listing |
PLoS One
January 2025
Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America.
In this work, we propose a non-contact video-based approach that estimates an individual's blood pressure. The estimation of blood pressure is critical for monitoring hypertension and cardiovascular diseases such as coronary artery disease or stroke. Estimation of blood pressure is typically achieved using contact-based devices which apply pressure on the arm through a cuff.
View Article and Find Full Text PDFHeliyon
January 2025
Natural Composites Research Group Lab, Department of Materials and Production Engineering, The Sirindhorn International Thai-German School of Engineering (TGGS), King Mongkut's University of Technology North Bangkok (KMUTNB), Bangkok, 10800, Thailand.
Fiber metal laminates (FMLs) have garnered significant attention due to their exceptional impact resistance, making them attractive for various structural applications. This review presents recent advancements in understanding the impact behavior of FMLs under low- and high-velocity impact scenarios. Low-velocity impacts, commonly encountered during manufacturing, handling, and tool drops, are discussed, with a focus on damage mechanisms, energy absorption capabilities, and influential factors such as impactor geometry and boundary conditions.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Shanghai 200092, China.
A new in situ fracturing-enhanced oxidative remediation approach was recommended in this study to achieve rapid and efficient remediation of low-permeability contaminated sites. The objective of this study was to evaluate the effects of permeability and potassium permanganate (KMnO) concentration on the oxidation effectiveness and kinetics of KMnO in phenanthrene (PHE)-contaminated soil through rigid-wall hydraulic conductivity tests and a series of laboratory experiments. The results indicate that for various low-permeability contaminated soils, there was a critical KMnO concentration to significantly reduce the remediation time and a critical Darcy velocity to meet remediation goals.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, United States.
Ion optics are crucial for spectrometric methods such as mass spectrometry (MS) and ion mobility spectrometry (IMS). Among the wide selection of ion optics, temporal ion gates are of particular importance for time-of-flight MS (TOF-MS) and drift-tube IMS. Commonly implemented as electrostatic ion gates, these optics offer a rapid, efficient means to block ion beams and form discrete ion packets for subsequent analysis.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India.
Experiments were conducted in controlled laboratory conditions to determine the size-resolved CCN (Cloud Condensation Nuclei) activity of sub micrometer-sized aerosols containing nuclear fission products (CsI and CsOH) and abundant ambient inorganic aerosols ammonium sulphates ((NH)SO), ammonium chloride (NHCl), sodium nitrate (NaNO), and sodium chloride (NaCl). The presence of these atmospheric-relevant compounds internally mixed with fission product compounds has the potential to affect the capacity of ambient particulates of aerosols to absorb water and function as CCN. Once in the atmosphere, the dynamics of airborne radionuclides and subsequently their fate gets affected by dry and wet deposition processes.
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