المؤلفون: Pandit, Meelyn M.^1,2 (AUTHOR), Bridge, Eli S.^1,2 (AUTHOR), Ross, Jeremy D.^1,2 (AUTHOR) rossjd@ou.edu

المصدر: Ecology & Evolution (20457758). Oct2022, Vol. 12 Issue 10, p1-15. 15p.

مصطلحات موضوعية: *VOICE culture, *ACOUSTIC wave propagation, *WEATHER, *GRASSLANDS, *CLIMATE change, *AUDIO frequency, *DROUGHTS

مصطلحات جغرافية: UNITED States

مستخلص: Climate change is increasing aridity in grassland and desert habitats across the southwestern United States, reducing available resources and drastically changing the breeding habitat of many bird species. Increases in aridity reduce sound propagation distances, potentially impacting habitat soundscapes, and could lead to a breakdown of the avian soundscapes in the form of loss of vocal culture, reduced mating opportunities, and local population extinctions. We developed an agent‐based model to examine how changes in aridity will affect both sound propagation and the ability of territorial birds to audibly contact their neighbors. We simulated vocal signal attenuation under a variety of environmental scenarios for the south, central semi‐arid prairies of the United States, ranging from contemporary weather conditions to predicted droughts under climate change. We also simulated how changes in physiological conditions, mainly evaporative water loss (EWL), would affect singing behavior. Under contemporary and climate change‐induced drought conditions, we found that significantly fewer individuals successfully contacted all adjacent neighbors than did individuals in either the contemporary or predicted climate change conditions. We also found that at higher sound frequencies and higher EWL, fewer individuals were able to successfully contact all their neighbors, particularly in drought and climate change drought conditions. These results indicate that climate change‐mediated aridification may alter the avian soundscape, such that vocal communication no longer effectively functions for mate attraction or territorial defense. As climate change progresses, increased aridity in current grasslands may favor shifts toward low‐frequency songs, colonial resource use, and altered songbird community compositions. [ABSTRACT FROM AUTHOR]

المؤلفون: Lehmann, Fanny, Gatti, Filippo, Bertin, Michaël, Clouteau, Didier

المساهمون: CEA, DAM, DIF, F-91297 Arpajon, Laboratoire de Mécanique Paris-Saclay (LMPS), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay)

المصدر: NeurIPS AI for Science workshop ; https://hal.science/hal-04476126Test ; NeurIPS AI for Science workshop, Dec 2023, New Orleans, United States

مصطلحات موضوعية: Neural Operators, Transfer learning, Seismic hazard analysis, Wave propagation, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI]

جغرافية الموضوع: New Orleans, United States

الوصف: International audience ; Seismic hazard analyses in the area of a nuclear installation must account for a large number of uncertainties, including limited geological knowledge. It is known that some geological features can create site-effects that considerably amplify ground motion. Combining the accuracy of physics-based simulations with the expressivity of deep neural networks can help quantifying the influence of geological heterogeneities on surface ground motion. This work demonstrates the use of a Factorized Fourier Neural Operator (F-FNO) that learns the relationship between 3D heterogeneous geologies and time-dependent surface wavefields. The F-FNO was pretrained on the generic HEMEW-3D database made of 30 000 samples. Then, a smaller database was built specifically for the region of the Le Teil earthquake (South-Eastern France) and the F-FNO was further trained with only 250 specific samples. Transfer learning improved the prediction error by 22 %. As quantified by the Goodness-Of-Fit (GOF) criteria, 90 % of predictions had excellent phase GOF (62 % for the enveloppe GOF). Although the intensity measures of surface ground motion were, in average, slightly underestimated by the FNO, considering a set of heterogeneous geologies always led to ground motion intensities larger than those obtained from a single homogeneous geology. These results suggest that neural operators are an efficient tool to quantify the range of ground motions that a nuclear installation could face in the presence of geological uncertainties. The HEMEW-3D database and the pretrained F-FNO model are publicly available to facilitate further developments and applications.

العلاقة: hal-04476126; https://hal.science/hal-04476126Test; https://hal.science/hal-04476126/documentTest; https://hal.science/hal-04476126/file/Lehmann%20et%20al.%20-%202023%20-%20Seismic%20hazard%20analysis%20with%20a%20Factorized%20Fourier%20.pdfTest

الإتاحة: https://hal.science/hal-04476126Test
https://hal.science/hal-04476126/documentTest
https://hal.science/hal-04476126/file/Lehmann%20et%20al.%20-%202023%20-%20Seismic%20hazard%20analysis%20with%20a%20Factorized%20Fourier%20.pdfTest

المؤلفون: DeCourcy, Brendan J., Lin, Ying-Tsong, Zhang, Weifeng Gordon, Ozanich, Emma Reeves, Kukshtel, Natalie, Siderius, Martin, Gawarkiewicz, Glen, Forsyth, Jacob

المصدر: Journal of the Acoustical Society of America; Nov2022, Vol. 152 Issue 5, p2859-2862, 4p

مصطلحات موضوعية: OCEAN circulation, CIRCULATION models, ACOUSTICS, ACOUSTIC wave propagation, SUBMARINE geology

مصطلحات جغرافية: UNITED States

مستخلص: During the spring of 2021, a coordinated multi-vessel effort was organized to study physical oceanography, marine geology and biology, and acoustics on the northeast United States continental shelf, as part of the New England Shelf Break Acoustics (NESBA) experiment. One scientific goal was to establish a real-time numerical model aboard the research vessel with high spatial and temporal resolution to predict the oceanography and sound propagation within the NESBA study area. The real-time forecast model performance and challenges are reported in this letter without adjustment or re-simulation after the cruise. Future research directions for post-experiment studies are also suggested. [ABSTRACT FROM AUTHOR]

: Copyright of Journal of the Acoustical Society of America is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Dalmora, Andre, Imperiale, Alexandre, Imperiale, Sébastien, Moireau, Philippe

المساهمون: Laboratoire Simulation et Modélisation Acoustique (CEA, LIST) (LSMA (CEA, LIST)), Département Imagerie et Simulation pour le Contrôle (CEA, LIST) (DISC (CEA, LIST)), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de mécanique des solides (LMS), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Paris (IP Paris), Mathematical and Mechanical Modeling with Data Interaction in Simulations for Medicine (M3DISIM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Paris (IP Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Paris (IP Paris)-Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), European Project: 860104,GW4SHM

المصدر: QNDE 2022 - 49th Annual Review of Progress in Quantitative Nondestructive Evaluation ; https://cea.hal.science/cea-04131482Test ; QNDE 2022 - 49th Annual Review of Progress in Quantitative Nondestructive Evaluation, Jul 2022, San Diego, CA, United States. ⟨10.1115/QNDE2022-98682⟩

مصطلحات موضوعية: Numerical Simulation, Wave Propagation, Struc- tural Health Monitoring, EOCs, Prestresses, Guided Waves, 3D Shell Elements, Spectral Finite Elements, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, [PHYS.MECA.SOLID]Physics [physics]/Mechanics [physics]/Solid mechanics [physics.class-ph]

جغرافية الموضوع: San Diego, CA, United States

الوصف: International audience ; In leading-edge industrial applications, assessing structure integrity is an important aspect of safety requirements. Structural Health Monitoring (SHM) proposes to use sensors and signal processing units in situ. One of the most attractive SHM techniques is ultrasonic guided waves. Guided waves propagate on large distances and interact with defects in the structure making damage detection possible. Modelling and simulation can be helpful tools for the design or the reliability assessment of SHM solutions. The currently available models developed for that purpose do not take into account the effect of operational conditions such as internal stresses. These conditions can modify wave propagation and therefore affect the interpretation of recorded signals. The objective of this work is to propose a model filling this gap, and to derive corresponding numerical methods for elastic wave propagation in an arbitrarily deformed medium. Any hyperelastic constitutive law can be considered. As the structures considered are usually thin, we avoid shear-locking by using a shell formulation to solve the quasi-static problem representing the effects of structure loading. The computed displacement is then fed into a spectral elements method (SEM) kernel to solve the time-domain linearized 3D elastodynamics problem representing the wave propagation. We validate our model for an isotropic aluminium plate under tensile forces. Additionally, we apply these numerical procedures to a realistic bending experiment of a steel pipe, illustrating the effects of stresses on ultrasonic guided wave propagation.

العلاقة: info:eu-repo/grantAgreement//860104/EU/Guided Waves for Structural Health Monitoring/GW4SHM; cea-04131482; https://cea.hal.science/cea-04131482Test; https://cea.hal.science/cea-04131482/documentTest; https://cea.hal.science/cea-04131482/file/Article%20Andre%20Dalmora%20QNDE_2022.pdfTest

الإتاحة: https://doi.org/10.1115/QNDE2022-98682Test
https://cea.hal.science/cea-04131482Test
https://cea.hal.science/cea-04131482/documentTest
https://cea.hal.science/cea-04131482/file/Article%20Andre%20Dalmora%20QNDE_2022.pdfTest

المؤلفون: Tunc, Celal Alp¹ celal@ee.bilkent.edu.tr, Altintas, Ayhan¹, Ertürk, Vakur B.¹

المصدر: IEEE Transactions on Antennas & Propagation. Sep2005, Vol. 53 Issue 9, p3080-3083. 4p.

مصطلحات موضوعية: *STOCHASTIC models, ELECTROMAGNETIC measurements, RADIO wave propagation, INTEGRAL equations

مصطلحات جغرافية: UNITED States

الشركة/الكيان: INTERNATIONAL Telecommunication Union , UNITED States. Federal Communications Commission

مستخلص: The accuracy of most widely used empirical models are investigated using the spectrally accelerated forward-backward (FBSA) method as a benchmark solution. First, FBSA results are obtained for propagation over large scale terrain profiles and compared with measurements to assess the accuracy of FBSA. Then, accuracy of some International Telecommunication Union (ITU) and Federal Communications Commission (FCC) propagation models are investigated. It has been observed that, for rural areas, the prediction of the most recent ITU recommended propagation model (Rec. 1546) deviates much more than older models do. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Antennas & Propagation is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Liang, George, Bertoni, Henry L.

المصدر: IEEE Transactions on Antennas & Propagation. Jun98, Vol. 46 Issue 6, p853. 11p. 2 Black and White Photographs, 6 Diagrams, 3 Charts, 7 Graphs.

مصطلحات موضوعية: RADIO wave propagation, CITIES & towns

مصطلحات جغرافية: VIRGINIA, UNITED States

مستخلص: Describes the development of a vertical-plane-launch (VPL) technique for approximating a full three-dimensional (3-D) site-specific ray trace to predict radio wave propagation effects in cities. Comparison of the predictions of the VPL technique with measurements for Rosslyn, Virginia; Improvement showed by the VPL method.

المؤلفون: Albert, Donald G.¹ Donald.G.Albert@usace.army.mil, Swearingen, Michelle E.², Perron Jr., Frank E.¹, Carbee, David L.¹

المصدر: Journal of the Acoustical Society of America. Aug2015, Vol. 138 Issue 2, p735-747. 13p.

مصطلحات موضوعية: *ACOUSTIC pulses, *ACOUSTIC wave propagation, *FORESTS & forestry, *WAVE analysis, *POROUS materials, *REVERBERATION time, *DECIDUOUS forests, *SPRUCE

مصطلحات جغرافية: UNITED States

مستخلص: Measurements of acoustic pulse propagation for a 30-m path were conducted in an open field and in seven different forest stands in the northeastern United States consisting of deciduous, evergreen, or mixed tree species. The waveforms recorded in forest generally show the pulse elongation characteristic of propagation over a highly porous ground surface, with high frequency scattered arrivals superimposed on the basic waveform shape. Waveform analysis conducted to determine ground properties resulted in acoustically determined layer thicknesses of 4-8 cm in summer, within 2 cm of the directly measured thickness of the litter layers. In winter the acoustic thicknesses correlated with the site-specific snow cover depths. Effective flow resistivity values of 50-88 kN s m-4 were derived for the forest sites in summer, while lower values typical for snow were found in winter. Reverberation times (T60) were typically around 2s, but two stands (deciduous and pruned spruce planted on a square grid) had lower values of about 1.2s. One site with a very rough ground surface had very low summer flow resistivity value and also had the longest reverberation time of about 3s. These measurements can provide parameters useful for theoretical predictions of acoustic propagation within forests. [ABSTRACT FROM AUTHOR]

المؤلفون: Green, Dana M., Mull, Nathaniel, Scolman, Tucker, Griffiths, Grace, Pasch, Bret

المصدر: Behaviour; Nov2020, Vol. 157 Issue 14/15, p1211-1229, 19p

مصطلحات موضوعية: SOUNDS, GRASSHOPPERS, TRANSMISSION of sound, ACOUSTIC wave propagation, ANIMAL communication, WOODY plants

مصطلحات جغرافية: UNITED States

مستخلص: The efficacy of animal acoustic communication depends on signal transmission through an oft-cluttered environment. Anthropogenic-induced changes in vegetation may affect sound propagation and thus habitat quality, but few studies have explored this hypothesis. In the southwestern United States, fire suppression and cattle grazing have facilitated displacement of grasslands by pinyon-juniper woodlands. Northern grasshopper mice (Onychomys leucogaster) inhabit regions impacted by juniper encroachment and produce long-distance vocalizations to advertise their presence to conspecifics. In this study, we coupled acoustic recordings and electrophysiological measurements of hearing sensitivity from wild mice in the laboratory with sound transmission experiments of synthesized calls in the field to estimate the active space (maximum distance that stimuli are detected) of grasshopper mouse vocalizations. We found that mice can detect loud (85 dB SPL at 1 m) 11.6 kHz vocalizations at 28 dB SPL. Sound transmission experiments revealed that signal active space is approximately 50 m. However, we found no effect of woody plant encroachment on call propagation because juniper and woody plant density were inversely associated and both present barriers to a 9 cm mouse advertising at ground level. Our data indicate that woody plant encroachment does not directly impact the efficacy of grasshopper mouse communication, but vegetation shifts may negatively impact mice via alternative mechanisms. Identifying the maximum distance that vocalizations function provides an important metric to understand the ecological context of species-specific signalling and potential responses to environmental change. [ABSTRACT FROM AUTHOR]

: Copyright of Behaviour is the property of Brill Academic Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Li, Yang, Brossier, Romain, Métivier, Ludovic

المساهمون: Laboratoire d'automatique et de génie des procédés (LAGEP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Equations aux Dérivées Partielles (EDP ), Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )

المصدر: SEG Technical Program Expanded Abstracts 2019 ; SEG 2019 annual meeting ; https://hal.science/hal-02325586Test ; SEG 2019 annual meeting, Sep 2019, San Antonio, United States. pp.3770-3774, ⟨10.1190/segam2019-3215003.1⟩

مصطلحات موضوعية: frequency-domain, 3D, elastic, modeling, wave propagation, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation

جغرافية الموضوع: San Antonio, United States

الوقت: San Antonio, United States

الوصف: International audience ; A feasibility study on 3D frequency-domain anisotropic elastic wave modeling is conducted. The spectral element method is applied to discretize the 3D frequency-domain anisotropic elastic wave equation and the linear system is solved by parallel direct solvers, MUMPS andWSMP. A hybrid implementation of MPI and OpenMP for MUMPS is shown to be more efficient in flops and memory cost during the factorization. The influence of complex topography on MUMPS performance is negligible. With available resources, the largest scale modeling, 30 wavelengths in each dimension, is achieved. Using the block lowrank feature ofMUMPSleads to computational gains compared with the full-rank version. Limitation of MUMPS scalability for large number of MPI processes prompts us to investigate the performance of an alternative linear solver,WSMP. Preliminary comparison on small scale modelings shows a better scalability of WSMP while being more computational demanding.

العلاقة: hal-02325586; https://hal.science/hal-02325586Test; https://hal.science/hal-02325586/documentTest; https://hal.science/hal-02325586/file/2019_SEG_Li_FDSEM_submitted.pdfTest

الإتاحة: https://doi.org/10.1190/segam2019-3215003.1Test
https://hal.science/hal-02325586Test
https://hal.science/hal-02325586/documentTest
https://hal.science/hal-02325586/file/2019_SEG_Li_FDSEM_submitted.pdfTest

المؤلفون: Oumeziane, Amina Ait, Parisse, Jean-Denis

المساهمون: Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement (RAPSODEE), Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT), Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche de l'École de l'air (CReA), Armée de l'air et de l'espace

المصدر: ISBN: 978-1-62410-589-0 ; AIAA Aviation 2019 Forum ; https://hal.science/hal-03361272Test ; AIAA Aviation 2019 Forum, Jun 2019, Dallas, United States. 14 p., ⟨10.2514/6.2019-3568⟩ ; https://arc.aiaa.org/doi/book/10.2514/MAVIAT19Test.

مصطلحات موضوعية: Thermal Ablation, Thermal Effects, Stimulated Emission, Laser Ablation, Absorption Coefficient, Mass Flow, Thermal Modeling, Flux Corrected Transport, Shock Wave Propagation, Conservation Equations, [PHYS]Physics [physics], [SPI]Engineering Sciences [physics]

جغرافية الموضوع: Dallas, United States

الوصف: International audience

العلاقة: hal-03361272; https://hal.science/hal-03361272Test; https://hal.science/hal-03361272/documentTest; https://hal.science/hal-03361272/file/aiaa_2019.pdfTest

الإتاحة: https://doi.org/10.2514/6.2019-3568Test
https://doi.org/10.2514/MAVIAT19Test
https://hal.science/hal-03361272Test
https://hal.science/hal-03361272/documentTest
https://hal.science/hal-03361272/file/aiaa_2019.pdfTest