Дисертації з теми "High frequency gravity waves"
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Yu, Yonghui. "MODEL STUDIES OF TIME-DEPENDENT DUCTING FOR HIGH-FREQUENCY GRAVITY WAVES AND ASSOCIATED AIRGLOW RESPONSES IN THE UPPER ATMOSPHER." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3623.
Повний текст джерелаPh.D.
Department of Physics
Sciences
Physics PhD
Malenova, Gabriela. "Uncertainty quantification for high frequency waves." Licentiate thesis, KTH, Numerisk analys, NA, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186287.
Повний текст джерелаQC 20160510
De, Deuge Maria. "Optical observations of gravity waves in the high-latitude thermosphere /." Title page, abstract and contents only, 1990. http://web4.library.adelaide.edu.au/theses/09SM/09smd485.pdf.
Повний текст джерелаFozard, John Andrew. "Diffraction and scattering of high frequency waves." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433239.
Повний текст джерелаKoen, Etienne. "A Simulation Approach to High-Frequency Plasma Waves." Licentiate thesis, KTH, Rymd- och plasmafysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-106822.
Повний текст джерелаQC 20121205
Suedan, Gibreel A. "High frequency beam diffraction by apertures and reflectors." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27545.
Повний текст джерелаApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Ford, E. A. K. "Gravity waves and small-scale structure of the high-latitude upper atmosphere." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1445456/.
Повний текст джерелаAl-Balushi, K. R. N. "The use of high frequency stress waves for monitoring gears." Thesis, Cranfield University, 1995. http://dspace.lib.cranfield.ac.uk/handle/1826/10575.
Повний текст джерелаAl-Balushi, Khamis Rajab Nasser. "The use of high frequency stress waves for monitoring gears." Thesis, Cranfield University, 1995. http://dspace.lib.cranfield.ac.uk/handle/1826/10575.
Повний текст джерелаKipp, Robert. "Mixed potential integral equation solutions for layered media structures : high frequency interconnects and frequency selective surfaces /." Thesis, Connect to this title online; UW restricted, 1993. http://hdl.handle.net/1773/5974.
Повний текст джерелаNegale, Michael. "Investigating the Climatology of Mesospheric and Thermospheric Gravity Waves at High Northern Latitudes." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/6937.
Повний текст джерелаBallard, Valerie Jean. "Experiments with a high frequency laser slope meter." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367969.
Повний текст джерелаAlexander, C. Shafe. "High frequency enrichment in the p-wave coda of earthquakes." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/26227.
Повний текст джерелаSalomon, Michael. "Properties of Gravity Probe B gyroscopes obtained from high frequency SQUID signal /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Повний текст джерелаPopovic, Jelena. "Fast Adaptive Numerical Methods for High Frequency Waves and Interface Tracking." Doctoral thesis, KTH, Numerisk analys, NA (stängd 2012-06-30), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105062.
Повний текст джерелаQC 20121116
Albert, Blace Chandler. "Characterization of nonlinearities in the propagation of high frequency seismic waves." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/19432.
Повний текст джерелаAurangzeb, Mohammad. "Fault location on a transmission line using high frequency travelling waves." Thesis, University of Manchester, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488336.
Повний текст джерелаMiseikis, Vaidotas. "The interaction of graphene with high-frequency acoustic and electromagnetic waves." Thesis, University of Leeds, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595843.
Повний текст джерелаHizam, H. "Fault location on a distribution feeder using high frequency travelling waves." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403225.
Повний текст джерелаKarlbom, Linus. "Computing the Energy of High Frequency Waves in a Confined Domain." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102406.
Повний текст джерелаA method for computing the energy of the high frequency wave field inside a bounded two-dimensional domain is presented. The method is based on approximating the energy using ray tracing. The rays originate from a point source and are reflected (perfectly) at the boundary. The energy in a part of the domain is the sum of the energies in the rays passing through it. The method has been implemented in the computing program MATLAB. Numerical experiments have been made for various cases. Among these is a simple case where the correct solution is known and it has been verified that the method converges towards this correct solution. Results for a case where the correct solution is unknown have been compared with a simulation of Helmholtz equation using the program COMSOL Multiphysics.
Bisignano, Davide. "Modal approach to elastic and gravity waves in laterally heterogeneous media: from tsunami to acoustic frequency range." Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8605.
Повний текст джерелаIl presente lavoro di tesi presenta diverse applicazioni e sviluppi del metodo modale: in particolare, immaginando un percorso logico dalle basse alle alte frequenze, si sono considerate le onde di tsunami, onde sismiche propagantesi in strutture a forte eterogeneità laterale, fino a giungere all’applicazione del metodo al dominio acustico. Nel primo capitolo l’argomento trat- tato è quello degli tsunami (onde di gravità a lungo periodo), estendendo la tecnica modale agli tsunami e mostrando come questa metodologia consenta diversi approcci alla modellazione sia delle eterogeneità del modello strutturale che del processo di rottura sismico che genera l’onda di tsunami. Queste tecniche sono state applicate in diversi contesti, sia al fine di validarne i rela- tivi codici di calcolo (Mar Mediterraneo Occidentale, terremoto e tsunami di Tohoku del marzo 2011) che per valutare scenari di pericolosità da tsunami per le zone considerate (costa del Viet- nam, Mare Adriatico). L’argomento del secondo capitolo è la modellazione di onde sismiche che si propagano in modelli a forte eterogeneità laterale, in particolare con interfacce verticali liquido-solido. Dopo una breve introduzione teorica, vengono mostrati i risultati di alcuni test di modellazione che utilizzano vari modelli strutturali e diversi domini di frequenza (in parti- colare si arriverà a una frequenza massima di 10Hz). Quindi, andando a frequenze sempre più alte, fino a 100Hz, il pacchetto di programmi sviluppato originariamente per le onde sismiche è stato testato e, dopo gli opportuni miglioramenti, utilizzato per studiare la propagazione di onde acustiche in strutture oceaniche. Il fine di questi test, argomento del terzo e conclusivo capitolo di questo lavoro, è capire la sensibilità delle onde acustiche alle caratteristiche della struttura in cui si propagano, come ad esempio la presenza di strati solidi sedimentari a bassa veloc- ità o di un canale a bassa velocità nel liquido. Nel secondo e nel terzo capitolo lo studio dei segnali ottenuti è stata approfondita mediante un’analisi congiunta tempo-frequenza (FTAN) che ha notevolmente aiutato a capirne le caratteristiche salienti, correlate sia alla sorgente che alla struttura, confermando ulteriormente la validità e la poliedricità dell’approccio modale in questo genere di studi.
In this thesis work, we presents several applications and developments of the modal method: in particular, imagining a logical path from low to high frequencies, are considered the tsunami waves, seismic waves propagating in structures with strong lateral heterogeneity, to conclude with the application of the method to the acoustic range. The topic treated in the first chapter is the extension of the modal technique to the tsunami wavefield (long period gravity waves), showing how this methodology allows different approaches to the modeling of both heteroge- neous structural models and of the seismic rupture process that generates the tsunami. These techniques have been applied in different contexts, both in order to validate the computer codes (Western Mediterranean Sea, the Tohoku earthquake and tsunami of March 2011) and to as- sess tsunami hazard scenarios for the selected target zones (Vietnam Coasts, Adriatic Sea). The topic of the second chapter is the modeling of seismic waves propagating in strong laterally het- erogeneous models, in particular with vertical liquid-solid interfaces. After a short theoretical introduction, we shows the results of some modelling tests adopting several structural models and different frequency ranges (in particular reaching a maximum frequency of 10 Hz). Thus, going to higher frequencies, up to 100Hz, the package of programs originally developed for the seismic waves has been tested and, after appropriate improvements, used to study the propa- gation of acoustic waves in the oceanic structures. The purpose of these tests, subject of the third and final chapter of this work, is to understand the sensitivity of the acoustic waves to the characteristics of the structure in which they propagate, such as the presence of low velocity sedimentary layers or a low velocity channel in the liquid. In the second and third chapter, the study of the computed signals was complemented through a joint time-frequency analisys (FTAN) which greatly helped to understand their salient features, related to both the source and the structure, further confirming the validity and the polyhedric nature of the modal approach.
XXV Ciclo
1978
Martínez, Gómez David. "High-frequency waves and instabilities in multi-fluid partially ionized solar plasmas." Doctoral thesis, Universitat de les Illes Balears, 2018. http://hdl.handle.net/10803/461007.
Повний текст джерелаLa atmósfera solar es un ambiente altamente dinámico en el que se ha detectado una gran variedad de ondas e inestabilidades. La materia en tal región se encuentra en estado de plasma, por lo que es afectada por la presencia de campos electromagnéticos. Para comprender su dinámica, se requiere una teoría que combine las ecuaciones que describen las propiedades y evolución de los fluidos con las de los campos eléctricos y magnéticos. Entre las diferentes alternativas disponibles que cumplen las condiciones mencionadas, la magnetohidrodinámica (MHD) ideal es una descripción útil cuando los fenómenos de interés están asociados a frecuencias bajas. Para escalas temporales largas, las especies componentes del plasma están fuertemente acopladas y pueden ser tratadas como un fluido único. Para escalas temporales más cortas, el acoplamiento es más débil y las colisiones entre las distintas especies producen un desvío en las propiedades de las ondas respecto a las predichas por la MHD ideal. Consecuentemente, se necesita una teoría más compleja y precisa. En esta Tesis se presenta una teoría multi-fluido que tiene en cuenta los efectos de las colisiones ión-neutro, las colisiones de Coulomb y la difusividad magnética, y usa una ley de Ohm generalizada que incluye el término de Hall. Tal teoría es luego aplicada a la investigación de ondas e inestabilidades en varias capas y estructuras de la atmósfera solar, como la corona y el viento solar, que están completamente ionizados, y la cromosfera y protuberancias, que se hayan parcialmente ionizadas. Mediante simulaciones numéricas y el análisis de la relación de dispersión para perturbaciones transversales de pequeña amplitud, se estudia el impacto que las colisiones tienen en las propiedades de las ondas de Alfvén, de baja frecuencia, y los modos ión-ciclotrón y \textit{whistler}, de alta frecuencia. El atenuamiento causado por la fricción debida a las colisiones está dominado por la interacción ión-neutro a bajas frecuencias y por las colisiones de Coulomb y la difusividad magnética a altas frecuencias. Además, las regiones de corte y resonancias que las ondas ión-ciclotrón tienen en fluidos sin colisiones desaparecen cuando éstas son tenidas en cuenta. También se muestra que la inclusión del término de Hall es fundamental para describir correctamente las ondas de alta frecuencia en plasmas débilmente ionizados. También se estudian efectos no lineales, como el calentamiento, y perturbaciones de gran amplitud. Por una parte, se demuestra que la fuerza ponderomotriz generada por ondas de Alfvén no lineales, que causan variaciones en la densidad y presión del plasma, es fuertemente afectada por la interacción de iones con neutros. Por otra, la fricción debida a colisiones causa la disipación de la energía de las perturbaciones. Una fracción de esa energía es transformada en calor y aumenta la temperatura del fluido. Así, el plasma en una protuberancia quiescente o en la cromosfera puede ser calentado mediante las colisiones ión-neutro. Finalmente, también se investiga el efecto de flujos de cizalladura en la interfaz entre dos medios parcialmente ionizados. La presencia de dichos flujos lleva al desarrollo de la inestabilidad de Kelvin-Helmholtz. Aquí, se estudia la fase inicial de dicha inestabilidad, con la aplicación al caso particular de hilos cilíndricos de filamentos solares. El acoplamiento mediante colisiones entre iones y neutros reduce los ritmos de crecimiento de la inestabilidad para flujos sub-Alfvénicos pero no evita por completo su aparición, lo que significa que los plasmas parcialmente ionizados son inestables para cualquier valor del flujo de cizalladura. La comparación de los resultados analíticos con observaciones realizadas por otros autores muestra que, para un rango de parametros de las perturbaciones, los ritmos de crecimiento calculados son compatibles con la vida media típica de los hilos.
L'atmosfera solar és un ambient altament dinàmic en el que s'ha detectat una gran varietat d'ones i inestabilitats. La matèria en aquesta regió es troba en estat de plasma, i per tant es veu afectada per la presència de camps electromagnètics. Per comprendre la seva dinàmica es requereix una teoria que combini les equacions que descriuen les propietats i l'evolució dels fluids amb les del camps elèctrics i magnètics. De les diverses alternatives disponibles que compleixen els requeriments anteriorment citats, la magnetohidrodinàmica (MHD) ideal és una descripció útil quan els fenòmens d'interès estan associats a freqüències baixes. Per escales temporals llargues, les espècies que componen el plasma es troben fortament acoblades i poden ser tractades com a un únic fluid. Pel contrari, quan les escales temporals són més curtes, l'acoblament és més feble i les col·lisions entre les distintes espècies produeixen desviacions en les propietats de les ones respecte a les esperades en MHD ideal. En conseqüència, és necessàri una teoria més complexa i precisa. En aquesta Tesi es presenta una teoria multi-fluid que té en compte els efectes de les col·lisions ió-neutre, les col·lisions de Coulomb i la difusivitat magnètica, i utilitza una llei d'Ohm generalitzada que inclou el terme de Hall. Aquesta teoria s'aplica a la invesigació d'ones i inestabilitats en diverses capes i estructures de l'atmosfera solar, com són la corona i el vent solar, que estan completament ionitzats, i la cromosfera i protuberàncies, que es troben parcialment ionitzats. Mitjançat les simulaciones numèriques i l'anàlisi de la relació de dispersió per pertorbacions transversals de petita amplitud, s'estudia l'impacte que les col·lisions tenen en les propietats de les ones d'Alfvén, de baixa freqüència i els modes ió-ciclotró i \textit{whistler}, d'alta freqüència. L'atenuació produïda per la fricció deguda a les col·lisions està dominada per la interacció ió-neutre a baixes freqüències i per les col·lisions de Coulomb i la difusivitat magnètica a altes freqüències. A més, les regions de tall i ressonàncies que les ones ió-ciclotró tenen en els fluids sense col·lisions desapareixen quan aquestes s'inclouen al model. També s'ha trobat que l'efecte del terme de Hall és fonamental per descriure correctament les ones d'alta freqüència en plasmes dèbilment ionitzats. També s'estudien efectes no lineals, com és l'escalfament, i pertorbacions de gran amplitud. Per una banda, se demostra que la força ponderomotriu generada per ones d'Alfvén no lineals, que causen variacions en la densitat i pressió del plasma, està fortament afectada per la interacció del ions amb els neutres. Per altra banda, la fricció deguda a les col·lisions causa la dissipació de l'energia de les pertorbacions. Una fracció d'aquesta energia és transformada en calor i augmenta la temperatura del fluid. D'aquesta manera, el plasma en una protuberància quiescent o en la cromosfera pot ser escalfat mitjançant les col·lisions ió-neutre. Finalment, també s'investiga l'efecte d'un flux amb cisalladura en l'interfase entre dos medis parcialment ionitzats. La presència del flux dona lloc al desenvolupament de l'inestabilitat de Kelvin-Helmholtz. Aquí, s'estudia la fase inicial d'aquesta inestabilitat, aplicada al cas particular de fils cilíndrics en filaments solars. L'acoblament a través de les col·lisions entre ions i neutres redueix el ritme de creixement de l'inestabilitat per fluxos sub-Alfvénics però no evita per complet la seva aparició, el que significa que els plasmes parcialment ionitzats són inestables per qualsevol valor del flux de cisalladura. La comparació dels resultats analítics amb observacions realitzades per altres autors mostra que, per un rang de paràmetres de les pertorbacions, els ritmes de creixement calculats són compatibles amb la vida mitja típica dels fils a protuberàncies.
Drexler, Josef. "Determining the properties of low-frequency Farley-Buneman waves at high latitudes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ58028.pdf.
Повний текст джерелаMeyer, Patrik K. (Patrik Kristof). "The impact of high frequency/low energy seismic waves on unreinforced masonry." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38557.
Повний текст джерелаIncludes bibliographical references (p. [85]-87).
Traditionally, the high frequency components of earthquake loading are disregarded as a source of structural damage because of their small energy content and because their frequency is too high to resonate with the natural frequencies of structures. This thesis argues that higher frequency waves travelling through stiff masonry structures can trigger two types of failure mechanisms that have not yet been taken into account. First, the high frequencies can cause small vertical inter-stone vibrations that result in irreversible relative displacements of the stones, which may ultimately lead to collapse. The energy needed to cause this deformation and failure comes largely from gravitational forces. The second failure mechanism is associated with the increase of the outward thrust that results from the partial fluidization and densification of the loose granular inner core of some unreinforced masonry walls. Preliminary results of a series of static and dynamic tests, as well as of numerical models, demonstrate the potentially destructive effects of high frequency/low energy seismic waves on unreinforced masonry structures.
by Patrik K. Meyer.
S.M.
Kuehnert, Julian. "Simulation of High Frequency Seismic Waves generated by Rockfalls on Real Topography." Thesis, Université de Paris (2019-....), 2019. https://theses.md.univ-paris-diderot.fr/KUEHNERT_Julian_va2.pdf.
Повний текст джерелаRockfall hazard has to be evaluated and monitored in order to prevent loss of life and infrastructure. In this regard it is important to create event catalogs and understand rockfall dynamics. Seismic waves can help for this purpose as they carry valuable information of the event. They are generated when rockfalls impact the ground and can be used to detect, classify and locate events. Beyond that, rockfall properties such as their volume and their dynamic behavior can be inferred. Yet, high frequency seismic signals (>1Hz) are poorly understood. This is because they are associated to complex seismic sources which are spatially distributed and can rapidly vary over time. On top of this, high frequency seismic waves are prone to be scattered and diffracted due to interactions with soil heterogeneities or surface topography. This thesis takes an important step forward to enhance understanding of high frequency rockfall seismic signals by simulating seismic wave propagation on domains with realistic velocity profiles and 3D surface topographies using the Spectral Element Method (SEM). The influence of the topography on the seismic wave field is investigated. It is found that topography induced amplification is substantially different between deep sources and sources located at the surface. This is because surface waves generated by shallow sources are exposed to constant scattering and diffraction when traveling along the surface. The energy decay along the surface is investigated for different velocity models and equations are derived to back-calculate the total seismic energy radiated by the source. This is of interest as the rockfall seismic energy is related to the rockfall volume. In order to account for topography effects, a correction factor is proposed which can be introduced in the energy calculation. Observed seismic signals generated by rockfall at Dolomieu crater on Piton de la Fournaise volcano, La Réunion, are analyzed. Synthetic seismograms are used to identify and interpret observed signals generated by single impacts. The influence of topography on the waveforms is demonstrated and the sensitivity on source location as well as source direction is evaluated. Signal characteristics such as amplitudes and frequency content are explained based on Hertz contact theory. Additionally, inter-station spectral ratios computed from rockfall seismic signals are shown to be characteristic of the source position. Comparison with simulated spectral ratios suggest that they are dominated by the propagation along the topography rather than the mechanism of the source. Based on these findings, a method is proposed for the localization of rockfalls using simulated inter-station energy ratios. The method is applied to localize rockfalls at Dolomieu crater. The implementation of the method involves a sliding time window which allows a straightforward application on continuous seismic signals. The potential of the method to monitor rockfall activity in real-time is emphasized
Chin, Eu-Jeen. "High performance vibration isolation techniques for the AIGO gravitational wave detector." University of Western Australia. School of Physics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0159.
Повний текст джерелаTrasobares, Sánchez Jorge. "High frequency electronics on nanodot molecular junctions : interaction between molecules, ions and waves." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10168/document.
Повний текст джерелаAn attractive combination of self-assembled monolayers on top of “Au” single crystal Nanoparticles (AuNp) and Scanning Probe Microscopies permits to explore the interaction between active molecules in the junction, as well as with the media. At the same time, we demonstrate the experimental proof of a molecular rectifying diode working at gigahertz frequency. Device fabrication by fast e-beam lithography allows their characterization by techniques that may need millimeter scale surfaces as well as by near field Scanning Probe Microscopies. Detection of a little number of molecules per AuNP promises interesting future research in the challenge of grafting and detecting single molecules per nanoparticle. On the one hand, this investigation confirms a recent theoretical prediction that cooperative effects between molecules may have an effect on the asymmetry of the conductance histogram line shape. On the other hand, established electrochemical theories are exploited to investigate similar factors such as interaction between redox molecules and the modification of the energy level of molecular orbitals. This study permits extracting a range of coupling energies between molecules that may be a first step towards the quantitative experimental estimation of this key parameter in molecular electronics. Thanks to an AFM connected to Network analyzer, we characterize a molecular diode operating at high frequency to 18 GHz with a rectification ratio of 12 dB (factor 4) at this frequency. Small capacitances in the order of few aF permit to see this behavior at high frequencies
Rokusek, Daniel L. "Excitation of Langmuir wave turbulence in high-frequency (HF) pump waves over Gakona, Alaska." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/41300.
Повний текст джерелаIncludes bibliographical references (p. 53).
(cont.) Investigated in this thesis are the excitation and observation of Langmuir wave turbulence caused by the parametric decay instability (PDI) in high-frequency space plasma heating experiments conducted at the NSF/DoD High Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska during the spring and summer of 2006. The PDI is the decay of an electromagnetic (EM) wave into an electron plasma wave (i.e., Langmuir wave) and an ion acoustic wave. When the excited Langmuir wave parametrically decays into another Langmuir and ion acoustic wave pair, a cascade of Langmuir waves can occur provided that the instability threshold is satisfied. According to recently advanced theory by Kuo and Lee [2005], there are two possible methods of cascade: non-resonant and resonant. While the non-resonant cascade proceeds at the location of excitation, the resonant process occurs at lower altitudes to minimize losses that the non-resonant process incurs by remaining at the excitation altitude. Such losses are caused by the frequency mismatch effect, as the decay ion acoustic wave frequency becomes much less than that of the normal ion acoustic waves. In their downward propagation the Langmuir waves in the resonant cascade suffer from propagation losses, however these losses are less than those associated with the non-resonant process. The resonant process is therefore expected to have a lower threshold. Theoretical claims and calculations are compared to observations made at Arecibo, Puerto Rico and Tromso, Norway. Claims are also are supported by incoherent backscatter radar observations made at the HAARP facility in Gakona.
by Daniel L. Rokusek.
S.M.
Baker, Andrew Ballard. "Effect of Interplanetary Shock Impact Angle on the Occurrence Rate and Properties of Pc5 Waves Observed by High-Latitude Ground Magnetometers." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90396.
Повний текст джерелаMaster of Science
Interplanetary shocks, drive interactions between the solar wind and the Earth’s atmosphere, and they have the potential to have far reaching consequences. Caused by a variety of solar events including both Coronal Mass Ejections (CMEs) and Co-rotating Interaction Regions (CIRs), they have the ability to physically move the locations of regional boundaries of the ionized part of Earth’s atmosphere, leading to a variety of electromagnetic effects. They also pose a danger at the human level by generating electrical currents in technological infrastructure that can overload transformers, communication cables, and power grids. As they pose a danger to our society, understanding them is prudent. A large portion of the current research into their behaviors has been focused on models and simulations and has shown that the shock impact angle should affect the properties of the waves. For this investigation, data from a series of Antarctic sensors was collected and compared to a database of known interplanetary shocks to determine when different shocks were detected. Specifically, for our investigation, we were concerned with determining what impact if any, the impact angle of the IP shock had on the generation of Pc5 waves, a specific type of ULF wave. This was accomplished by calculating the power level at different frequencies both before and after the shock. This information was then combined with the shock impact angle to determine what effects if any, the shock impact angle had on Pc5 wave occurrence rates. From our research we found that the impact angle of the interplanetary shock had a significant impact on the generation of Pc5 waves.
Kafle, Durga N. "Rayleigh-Lidar Observations of Mesospheric Gravity Wave Activity above Logan, Utah." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/466.
Повний текст джерелаArigong, Bayaner. "Space and Spectrum Engineered High Frequency Components and Circuits." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801923/.
Повний текст джерелаKim, Hyo Tae. "High frequency analysis of EM scattering from a circular conducting cylinder with dielectric/ferrite coating /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487322984315885.
Повний текст джерелаNoersomadi. "Characteristics of tropical tropopause and stratospheric gravity waves analyzed using high resolution temperature profiles from GNSS radio occultation." Kyoto University, 2019. http://hdl.handle.net/2433/242617.
Повний текст джерелаLiu, Horng-Twu. "The use of high frequency stress waves for detecting shaft seal rubbing and source location." Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309839.
Повний текст джерелаTrott, Keith Dennis. "A high frequency analysis of electromagnetic plane wave scattering by a fully illuminated perfectly conducting semi-infinite cone /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487323583622574.
Повний текст джерелаCardona, Orozco Yuley Mildrey. "Enhanced vertical mixing within mesoscale eddies due to high frequency winds in the south China sea." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44917.
Повний текст джерелаTshisaphungo, Mpho. "Validation of high frequency propagation prediction models over Africa." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1015239.
Повний текст джерелаCameron, Michelle. "Impact of low-frequency high-power ultrasound on spoilage and potentially pathogenic dairy microbes." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/597.
Повний текст джерелаOprisoni, Cristian Alexandru [Verfasser]. "Investigation of the high frequency dynamic-mechanical properties of polymer systems using ultrasonic longitudinal waves / Cristian Alexandru Oprisoni." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2011. http://d-nb.info/104185126X/34.
Повний текст джерелаWebster, Bruce Naakaii Ts'oh. "Low magnitude high frequency vibrations applied to the foot through the pedal of a human powered artificial gravity (HPAG) cycle." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34165.
Повний текст джерела"February 2006."
Includes bibliographical references (p. 87-88).
Astronauts are exposed to hazards unique to space travel. These hazards include radiation exposure and adaptation of the human body to the microgravity environment. For lunar and low earth orbital missions, the exposure period is typically less than six months and return to Earth is less than two weeks away. For travel beyond the Earth's moon, the microgravity exposure time will increase from months to years and return time will increase from weeks to months. Current countermeasures employ impact and high force loading to maintain bone health. An astronaut runs on a treadmill to impact load the weight bearing components of the musculoskeletal system. Elastic bands provide the "down" force for the astronaut while running. For high force loading, the astronaut performs a specified regimen of weight lifting exercises using resistive devices. The resistive devices provide a load in microgravity similar to that of free weights on Earth. These countermeasures have been beneficial in slowing bone adaptation, but have not stopped it. The imperceptible muscle contractions required for posture maintenance may be the absent load that the skeletal system requires to maintain bone health. Unlike the muscles that are required for impact and high force loading, the postural muscles work continuously to keep humans balanced and upright in a gravity environment.
(cont.) Jumping, running and even sitting require posture maintenance. Studies have shown that low magnitude loads applied at a high frequency to the weight bearing bones have not only maintained the bone mineral density, but also more importantly, maintained the structure of the bones. This thesis demonstrates the design of a vibrating pedal that delivers a perceptible, low magnitude load at a high frequency ([approx.]30 Hz) to the foot. This design required no external power and was implemented on a Human Powered Artificial Gravity (HPAG) cycle. A device similar to the vibrating pedal device created for this research could benefit society by providing an effective therapy against the disease of osteoporosis. A vibrating pedal could easily be mounted on a stationary cycle, possibly even standard bicycle, and provide a beneficial therapy to the user.
by Bruce Naakaii Ts'oh Webster.
S.M.
Myung, Noh Hoon. "A high frequency analysis of electromagnetic plane wave scattering by perfectly-conducting semi-infinite parallel plate and rectangular waveguides with absorber coated inner walls /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267546980859.
Повний текст джерелаPhillips, William Scott. "The separation of source, path and site effects on high frequency seismic waves : an analysis using coda wave techniques." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/59037.
Повний текст джерелаMicrofiche copy available in Archives and Science.
Bibliography: leaves 178-185.
by William Scott Phillips.
Ph.D.
Gill, Eric William. "The scattering of high frequency electromagnetic radiation from the ocean surface : an analysis based on a bistatic ground wave radar configuration /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0003/NQ42476.pdf.
Повний текст джерелаLeong, Jonathan Ryan Kyoung Ho. "Characterization of the Polarization and Frequency Selective Bolometric Detector Architecture." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1232487119.
Повний текст джерелаYang, Meng Verfasser], Christian [Akademischer Betreuer] Hirt, Dimitrios [Gutachter] Tsoulis, Christian [Gutachter] Hirt, and Roland [Gutachter] [Pail. "Investigation of the residual terrain modelling (RTM) technique for high-frequency gravity calculations / Meng Yang ; Gutachter: Dimitrios Tsoulis, Christian Hirt, Roland Pail ; Betreuer: Christian Hirt." München : Universitätsbibliothek der TU München, 2020. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20200108-1521921-1-4.
Повний текст джерелаYang, Meng [Verfasser], Christian [Akademischer Betreuer] Hirt, Dimitrios [Gutachter] Tsoulis, Christian [Gutachter] Hirt, and Roland [Gutachter] Pail. "Investigation of the residual terrain modelling (RTM) technique for high-frequency gravity calculations / Meng Yang ; Gutachter: Dimitrios Tsoulis, Christian Hirt, Roland Pail ; Betreuer: Christian Hirt." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/120546316X/34.
Повний текст джерелаHannay, Jonathan David. "Computational simulations of thermally activated magnetisation dynamics at high frequencies." Thesis, Bangor University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367315.
Повний текст джерелаJiménez, González Noe. "Nonlinear Acoustic Waves in Complex Media." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/53237.
Повний текст джерела[ES] La Naturaleza es no lineal. La descripción lineal de los fenómenos físicos es de gran utilidad para explicar nuestras observaciones con modelos matemáticos simples, pero éstos sólo son precisos en un limitado rango de validez. En el caso de onda acústica de alta intensidad, los modelos lineales obvian un amplio rango de fenómenos físicos que son necesarios para describir con precisión las ondas de gran amplitud, pero además son necesarios para explicar otros procesos más exóticos e indispensables para desarrollar nuevas aplicaciones basadas en propagación no lineal. En esta Tesis, estudiamos las interacciones entre no linealidad y otros procesos complejos como atenuación no-clásica, dispersión anisotrópica y periodicidad, y difracción en configuraciones específicas. En primer lugar, presentamos ondas de deformación en una cadena de cationes acoplados por potenciales realísticas. Aquí, las interacciones no lineales entre iones, producen la conformación de kinks supersónicos. Estas dislocaciones localizadas intrínsecamente no lineales viajan por la red largas distancias sin variar sus propiedades, y pueden explicar la formación de trazas en minerales como la mica. Aumentando la escala del problema, estudiamos los procesos acústicos no lineales en medios multicapa. La rica dinámica de estos medios está caracterizada por la fuerte dispersión debido a la periodicidad del sistema. Aquí, estudiamos los procesos de generación de harmónicos, mostrando como modificando la estructura podemos potenciar, minimizar, o simplemente modificar artificialmente la transferencia de energía entre las componentes espectrales, y de esta manera controlar la dinámica de las ondas y solitones en el interior de la estructura. En la segunda parte, incluimos difracción y analizamos cuatro tipos de haces singulares. En primer lugar, analizamos haces ultrasónicos no lineales en cristales de sonido bidimensionales. En este sistema, las propiedades de anisotropía del medio son ajustadas para obtener la auto-colimación simultánea del primer y segundo harmónico. Así, se obtiene la propagación no difractiva para las dos componentes. En segundo lugar, presentamos haces de difracción limitada empleando rejillas de difracción axisimétricas. Por último, demostramos la generación de haces de Bessel de orden superior mediante estructuras en espiral. En la última parte, estudiamos la competición entre no linealidad y la atenuación y dispersión observable en medios biológicos en el contexto de las aplicaciones de biomédicas de los ultrasonidos. En primer lugar desarrollamos un nuevo método computacional para la dependencia frecuencial en forma de ley de potencia de la absorción característica de los tejidos. Este método en dominio temporal es usado posteriormente para revisar los procesos básicos no lineales prestando especial interés en el paper de la dispersión del tejido. Por último, la resolución de las ecuaciones constitutivas nos permite abordar la descripción no lineal de la fuerza de radiación acústica producida en tejidos biológicos, y las implicaciones existentes con la deposición de energía y transferencia de momento para ondas ultrasónicas de alta intensidad. El amplio abanico de procesos no lineales analizados en esta tesis contribuye a una mejor comprensión de la dinámica de las ondas acústicas de alta intensidad en medios complejos, donde las implicaciones existentes en cuanto a la mejora de sus aplicaciones prácticas son puestas de manifiesto.
[CAT] La Naturalesa és no lineal. La descripció lineal dels fenòmens físics és de gran utilitat per a explicar les nostres observacions amb models matemàtics simples, però aquests sol són precisos en un limitat rang de validesa. En el cas d'ona acústica d'alta intensitat, els models lineals obvien un ampli rang de fenòmens físics que són necessaris per a descriure amb precisió les ones de gran amplitud, però a més són necessaris per a explicar altres processos més exòtics i indispensables per a desenvolupar noves aplicacions basades en propagació no lineal. En aquesta Tesi, estudiem les interaccions entre no-linealitat i altres processos complexos com atenuació no-clàssica, dispersió anisotròpica i periodicitat, i difracció en configuracions específiques. En primer lloc, presentem ones de deformació en una cadena de cations acoblats per potencials realistes. Ací, les interaccions no lineals entre ions, produeixen la conformació de kinks supersònics. Aquestes dislocacions localitzades intrínsecament no lineals viatgen per la xarxa llargues distàncies sense variar les seues propietats, i poden explicar la formació de traces en minerals com la mica. Augmentant l'escala del problema, estudiem els processos acústics no lineals en mitjans multicapa. La rica dinàmica d'aquests mitjans es caracteritza per la forta dispersió a causa de la periodicitat del sistema. Ací, estudiem els processos de generació d'harmònics, mostrant com modificant l'estructura podem potenciar, minimitzar, o simplement modificar artificialment la transferència d'energia entre les components espectrals, i d'aquesta manera controlar la dinàmica de les ones i solitons a l'interior de l'estructura. En la segona part, incloem difracció i analitzem quatre tipus de feixos singulars. En primer lloc, analitzem feixos ultrasònics no lineals en cristalls de so bidimensionals. En aquest sistema, les propietats d'anisotropia del medi són ajustades per a obtenir l'acte-col·limació simultània del primer i segon harmònic. Així, s'obté la propagació no difractiva per a les dues components. En segon lloc, presentem feixos de difracció limitada emprant reixetes de difracció axisimètriques. Per últim, vam demostrar la generació de feixos de Bessel d'ordre superior mitjançant estructures en espiral. En l'última part, estudiem la competició entre no linealitat i l'atenuació i dispersió observable en medis biològics en el context de les aplicacions biomèdiques dels ultrasons. En primer lloc desenvolupem un nou mètode computacional per a la dependència freqüencial en forma de llei de potència de l'absorció característica dels teixits biològics. Aquest mètode en domini temporal és usat posteriorment per a revisar els processos bàsics no lineals prestant especial interés en el paper de la dispersió del teixit. Per últim, la resolució de les equacions constitutives ens permet abordar la descripció no lineal de la força de radiació acústica produïda en teixits biològics, i les implicacions existents amb la deposició d'energia i transferència de moment per a ones ultrasòniques d'alta intensitat. L'ampli ventall de processos no lineals analitzats en aquesta tesi contribueix a una millor comprensió de la dinàmica de les ones acústiques d'alta intensitat en medis complexos, on les implicacions existents quant a la millora de les seues aplicacions practiques són posades de manifest.
Jiménez González, N. (2015). Nonlinear Acoustic Waves in Complex Media [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/53237
TESIS
Premiado
Polat, Ozgur Murat. "Ray Anlaysis Of Electromagnetic Scattering From Semi-infinite Array Of Dipoles In Free Space." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12608347/index.pdf.
Повний текст джерелаinfinite array of dipoles in free space. The analytical closed form expression for the array guided surface wave launching coefficient is obtained via a combination of an asymptotic high frequency analysis of a related reciprocal problem and Lorentz reciprocity integral formulation for the semi-infinite planar dipole array in which modified Kirchhoff approximation is used. The accuracy and the validity of the asymptotic analytical solutions are compared with the numerical solutions available in the literature before.
Cui, Xian. "Efficient radio frequency power amplifiers for wireless communications." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195652135.
Повний текст джерела