Dissertations / Theses on the topic 'Wake Penetration'
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Hepton, Peter. "Shear wave velocity measurements during penetration testing." Thesis, Bangor University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330070.
Full textGillespie, Donald G. (Donald Gardner). "Evaluating shear wave velocity and pore pressure data from the seismic cone penetration test." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30573.
Full textApplied Science, Faculty of
Civil Engineering, Department of
Graduate
Onaran, Özlem. "The effect of import penetration on labor market outcomes in Austrian manufacturing industry." Inst. für Volkswirtschaftstheorie und -politik, WU Vienna University of Economics and Business, 2008. http://epub.wu.ac.at/1264/1/document.pdf.
Full textSeries: Department of Economics Working Paper Series
Kabutz, Marten Herbert. "RF hardware design of a stepped frequency continuous wave ground penetrating radar." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/18227.
Full textResearch into stepped frequency continuous wave ground penetrating radar (SFCW GPR) at UCT has been carried out since 1990. A first generation system comprising of Hewlett-Packard test equipment controlled by a PC was assembled. Cavity-backed log spiral antennas were designed and built by the University of Stellenbosch for the specific use of ground penetrating radar. Measurements with the first generation system proved the concept of SFCW GPR and thus a dedicated second generation system was planned. A SFCW GPR system was designed to replace the first generation system. Various designs for transmitter and receiver configurations were investigated and those found most suitable were used for the implementation. The SFCW radar consists of a wideband CW transmitter and a coherent receiver. A 300-1000 MHz transmitter was constructed using varactor-tuned oscillators as frequency sources. A double-sideband, low-IF receiver was constructed for the 300- 1000 MHz signal, to mix it to an IF of 10.7 MHz and I-Q demodulate it. The transmitter was found to operate according to specifications. The receiver was found to operate satisfactorily, but the dynamic range was less than expected. A limiting problem encountered in the first generation GPR was the large direct coupling signal from the transmitter into the receiver. This large signal reduced the effective receiver dynamic range. A method of cancelling this large direct coupling signal was implemented, using a bi-phase modulator to generate the cancelling signal in antiphase to the coupling signal. A 20 dB reduction in coupling was shown. The system was used to measure cable lengths to within the inherent accuracy of the system. A metal plate target was detected by the system feeding two antenna and a concrete floor was detected under 1 m of sand. It was thus shown that the SFCW system could be used as a second generation GPR.
Blomqvist, Mikael. "Construction and evaluation of a magnetoresistive ground penetrating radar system." Thesis, Uppsala universitet, Ångström Space Technology Centre (ÅSTC), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-159904.
Full textZhao, Hongyi. "Numerical Analysis of Wave-induced Seabed Response in the Vicinity of Marine Structures." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/365468.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
Hall, James Kumar. "Accuracy of the method of steepest descents for a spherical wave penetrating a planar boundary." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ57290.pdf.
Full textRogge, Matthew Douglas. "In-process sensing of weld penetration depth using non-contact laser ultrasound system." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31698.
Full textCommittee Chair: Ume, Charles; Committee Member: Chen, Ye-Hwa; Committee Member: Michaels, Jennifer; Committee Member: Sadegh, Nader; Committee Member: Vachtsevanos, George. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Liao, Tianfei. "Post processing of cone penetration data for assessing seismic ground hazards, with application to the New Madrid seismic zone." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-05042005-133640/.
Full textMayne, Paul W., Committee Chair ; Goldsman, David, Committee Member ; Lai, James, Committee Member ; Rix, Glenn J., Committee Member ; Santamarina, J. Carlos, Committee Member.
Guha, Swagata. "Ground penetrating radar response to thin layers examples from Waites Island, South Carolina /." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0000593.
Full textLangman, Alan. "The design of hardware and signal processing for a stepped frequency continuous wave ground penetrating radar." Doctoral thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/6932.
Full textA Ground Penetrating Radar (GPR) sensor is required to provide information that will allow the user to detect, classify and identify the target. This is an extremely tough requirement, especially when one considers the limited amount of information provided by most GPRs to accomplish this task. One way of increasing this information is to capture the complete scattering matrix of the received radar waveform. The objective of this thesis is to develop a signal processing technique to extract polarimetric feature vectors from Stepped Frequency Continuous Wave (SFGWV) GPR data. This was achieved by first developing an algorithm to extract the parameters from single polarization SFCW GPR data and then extending this algorithm to extract target features from fully polarimetric data. A model is required to enable the extraction of target parameters from raw radar data. A single polarization SFCW GPR model is developed based on the radar geometry and linear approximations to the wavenumber in a lossy medium. Assuming high operating frequencies and/or low conductive losses, the model is shown to be equivalent to the exponential model found in signal processing theory. A number of algorithms exist to extract the required target parameters from the measured data in a least squared sense. In this thesis the Matrix Pencil-of-Function Method is used. Numerical simulations are presented to show the performance of this algorithm for increasing model error. Simulations are also provided to compare the standard Inverse Discrete Fourier Transform (IDFT) with the algorithm presented in this thesis. The processing is applied to two sets of measured radar data using the radar developed in the thesis. The technique was able to locate the position of the scatterers for both sets of data, thus demonstrating the success of the algorithm on practical measurements. The single polarization model is extended to a fully polarimetric SFCW GPR model. The model is shown to relate to the multi-dimensional exponential signal processing model, given certain assumptions about the target scattering damping factor. The multi-snapshot Matrix Pencil-of-Function Method is used to extract the scattering matrix parameters from the raw polarimetric stepped frequency data. Those Huynen target parameters that are independent of the properties of the medium, are extracted from the estimated scattering matrices. Simulations are performed to examine the performance of the algorithm for increasing conductive and dielectric losses. The algorithm is also applied to measured data for a number of targets buried a few centimeters below the ground surface, with promising results. Finally, the thesis describes the design and development of a low cost, compact and low power SFCW GPR system. It addresses both the philosophy as well as the technology that was used to develop a 200 - 1600 MHz and a 1 - 2 GHz system. The system is built around a dual synthesizer heterodyne architecture with a single intermediate frequency stage and a novel coherent demodulator system - with a single reference source. Comparison of the radar system with a commercial impulse system, shows that the results are of a similar quality. Further measurements demonstrate the radar performance for different field test cases, including the mapping of the bottom of an outdoor test site down to 1.6 m.
Watson, Francis Maurice. "Better imaging for landmine detection : an exploration of 3D full-wave inversion for ground-penetrating radar." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/better-imaging-for-landmine-detection-an-exploration-of-3d-fullwave-inversion-for-groundpenetrating-radar(720bab5f-03a7-4531-9a56-7121609b3ef0).html.
Full textMcGillivray, Alexander Vamie. "Enhanced Integration of Shear Wave Velocity Profiling in Direct-Push Site Characterization Systems." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19714.
Full textSule, Suki Dauda. "An evaluation of the performance of multi-static handheld ground penetrating radar using full wave inversion for landmine detection." Thesis, University of Hull, 2018. http://hydra.hull.ac.uk/resources/hull:16567.
Full textZietsman, Christian Frederick. "Theory, design and implementation of an IF cancellation module for use in a stepped frequency continuous wave ground penetrating radar." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/14972.
Full textA device has been designed that cancels the leakage signal between the transmit and receive antenna in a Stepped Frequency Continuous Wave Ground Penetrating Radar. The front end of the radar operates at high signal levels and, as a result, a large signal is coupled directly from the transmit to the receive antenna. This signal uses a signiï¬ cant part of the dynamic range of the data-capturing device, an analogue-to-digital converter (ADC). The objective of this cancellation is thus to increase the effective instantaneous dynamic range of the radar system. Simulations show that 10-bit amplitude and phase resolution in the digital cancellation circuit would achieve maximum cancellation in the presence of phase noise and other sources of error. This result is conï¬ rmed when the hardware is tested. The device was constructed and operates as intended. Tests show that cancellation exceeding 53dBm is possible through careful calibration. It was concluded that the device could successfully be integrated into the SFCW GPR and that it would achieve an increase in the instantaneous dynamic range.
Ku, Taeseo. "Geostatic stress state evaluation by directional shear wave velocities, with application towards geocharacterization at Aiken, SC." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45905.
Full textPark, Joongsuk. "Development of microwave and millimeter-wave integrated-circuit stepped-frequency radar sensors for surface and subsurface profiling." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/1588.
Full textDojack, Lisa Marie. "Assessing the utility of ground penetrating radar in archaeology on the Northwest Coast : the 'new wave', 'all Snell', or 'it just hertz'?" Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43041.
Full textChanda, Geoffrey. "Terahertz and infrared spectroscopy of novel superconductors." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-157061.
Full textSandikkaya, Mustafa Abdullah. "Site Classification Of Turkish National Strong-motion Recording Sites." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609728/index.pdf.
Full textHeiner, Brandon D. "Multi-Scale Neotectonic Study of the Clear Lake Fault Zone in the Sevier Desert Basin (Central Utah)." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3840.
Full textEscobar, Valencia Esteban Julio. "Mise au point et exploitation d'une nouvelle technique pour la reconnaisance des sols : le PANDA 3." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22570/document.
Full textThis work presents the recent developments made on the penetrometer PANDA®3. The instrumented dynamic penetrometer allowing, from the measurement and the decoupling of waves created by the impact, to obtain the load-penetration curve σp-sp of the soil. The exploitation of this curve allows determining the failure parameter (tip resistance qd), deformation (dynamic modulus EdP3), damping characteristics (Js) and wave speed (CsP3 and CpP3) of the investigated soil according to depth all along the sounding. However, although the proposed method is very interesting, it has remained at the stage of a laboratory prototype. It is therefore necessary to conduct a more thorough study of the test itself and the information provided from the σp-sp curve in order to obtain reliable measurement and improve their exploitation. First of all, we are presenting a brief overview of the geotechnical in-situ testing particularly that of the dynamic penetration tests as well as the general principle of PANDA 3 is presented. The second part is devoted to the development of a new prototype of the PANDA 3 penetrometer. This development is based on several studies aiming at validating the quality of the information, good reproducibility and treatment of the acquisition signals. Similarly, a discrete numerical model of the penetrometer developed using the Particle Flow Code software (Itasca) is presented to validate the measurement technique. The third part deals with a comparative study of the results obtained with the PANDA 3 and other in situ investigation techniques to validate the obtained results and the use of the device in real conditions. Moreover, the extension of this measurement technique in the case of heavy penetrometer is applied in order to measure the transmitted energy and to calibrate the driving system. The last part is devoted to refining the interpretation and exploitation of the load-penetration curve. The analysis of all the signals recorded in the laboratory allowed to approach a methodology of curve exploitation. The application of the proposed method was carried out for different soils both in the laboratory and on field. The results were confronted with other types of tests
Kohls, Nicholas Everett. "Software Defined Radio Short Range Radar." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9027.
Full textGomes, Maria da Graça. "Simulação e inversão de ondas eletromagnéticas em diferentes meios geológico-geotécnicos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/29054.
Full textThis work deals with simulation of a 1-D electromagnetic wave propagating into a geological structure of known physical properties (thickness, electric conductivity and permittivity), the record of the reflected EM wave (synthetic data), and the use of these records in inversion and optimization algorithms to estimate back the physical properties of the geological structure. A stratified and thin (< 1.2 m) geological structure was initially constructed in order to be scanned by high frequency EM waves (800, 1000, and 1200 MHz). The EM wave propagation is simulated by Maxwell equations through FDTD method. The Quasi-Newton inversion and Ant Colony Optimization methods were applied into synthetic data to estimate original physical parameters of each geological layer. Both methods were applied in order to increase precision and convergence along depth. These methods were able to simultaneously estimate two physical properties of the geological structure: electrical permittivity and conductivity. The methods showed good results when applied simultaneously upon synthetic data of all three frequencies. Electric permittivity and conductivity profiles are shown with and without noise in the data. The results indicate that combined inversion methods can show good results to estimate physical properties of thin geological and geothecnical structures. The combined inversion methods open new perspectives to multichannel GPR data processing. The investigations also show that simulation of synthetic data through FDTD can propagate errors when dealing with thick geological structures, due to the fact that FDTD is an explicit method.
Leroux, Maxime. "Supraconductivité, Onde de Densité de Charge et Phonons Mous dans les dichalcogénures 2H-NbSe2 et 2H-NbS2, et le composé intermétallique Lu5Ir4Si10." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENY069/document.
Full textThis thesis presents an experimental study of the interaction between superconductivity and a charge density wave (CDW). In the standard theory, the critical temperature of a superconductor is principally enhanced by two parameters: a large density of states at the Fermi level (nF) and a strong electron-phonon coupling. However, a strong electron-phonon coupling also favors the appearance of a CDW, which reduces nF and therefore competes with superconductivity.Our strategy was to study two compounds in which superconductivity and CDW coexist, and in which the CDW can be suppressed through an external parameter: pressure or substitution. The first compound is 2H-NbSe2, it presents a CDW below 33 K at ambient pressure. This CDW coexists with superconductivity below 7 K. Under pressure, the CDW disappears above 4.6 GPa, meanwhile the critical temperature slowly changes. The CDW also disappears when replacing selenium by sulfur: 2H-NbS2 is a superconductor without CDW (Tc=6 K), it can therefore serve as a “test compound” for a comparative study. The second compound is Lu5Ir4Si10, it presents a CDW below 77 K at ambient pressure. Under pressure, this CDW disappears above 2 GPa, meanwhile the critical temperature abruptly jumps from 4 to 9 K.For this study, I used three experimental techniques: inelastic x-ray scattering at low temperature (300-2 K) and under pressure (0-16 GPa) to measure the dispersion of phonons, a tunnel diode oscillator to measure the temperature dependence of the magnetic penetration depth, and Hall microprobes to measure the first and second critical fields. In the first part, I present the temperature dependence of the phonon dispersion in 2H-NbS2. We observe a soft phonon that always remains at positive energies, even extrapolated to zero temperature. Thus, this compound is on the verge of CDW instability. It is also relatively unique, since we show anharmonicity is the only effect that prevents the complete softening of the phonons.Then I present the temperature and pressure dependence of the phonon dispersion in 2H-NbSe2. These experiments show that a soft phonon persists up to 16 GPa, even if the ground state is not a CDW. The temperature dependence of this soft phonon is then similar to that of 2H-NbS2. In both compounds, these soft modes seem to be related to the strength and anisotropy of the electron-phonon coupling. We suggest this is a fundamental element to explain their superconducting properties.In the second part, I measure the anisotropy and temperature dependence of the magnetic penetration depth in the superconducting state of 2H-NbS2 and Lu5Ir4Si10. The temperature dependence of the superfluid density in 2H-NbS2 confirms the presence of a reduced superconducting gap. Its amplitude is very similar to the one measured in 2H-NbSe2. The soft modes and the reduced gap being present in both 2H-NbSe2 and 2H-NbS2, we prove experimentally that the enhancement of superconductivity is related to the soft modes rather than to the nature of the ground state (CDW or metal). We suggest this enhancement is due the anisotropy of the electron-phonon coupling.However, this effect is not general to all compounds where superconductivity and CDW coexist. The superconducting properties of Lu5Ir4Si10 are indeed well fitted by the BCS model in the weak coupling limit. This may be related to the characteristics of the CDW: the presence of hysteresis shows that the CDW transition is first order. In addition, under pressure and at low temperature, x-ray diffraction measurements indicate that the CDW is multiple: aside from the periodicity of 1/7, we observe a second periodicity of 1/20
Hazard, Colby. "Validity of Holocene Analogs for Ancient Carbonate Stratigraphic Successions: Insights from a Heterogeneous Pleistocene Carbonate Platform Deposit." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5496.
Full textLukiantchuki, Juliana Azoia. "Interpretação de resultados do ensaio SPT com base em instrumentação dinâmica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-24052013-103725/.
Full textThe standard penetration test (SPT) is usually used to estimate the soil strength through the NSPT index which represents the dynamic reaction force of the sampler penetration into the soil. This index is directly used in empirical or semi-empirical correlations for the determination of the bearing capacity and foundation settlements. However, this test has been criticized due to the use of these empirical correlations, often based on practical observation without any scientific basis. Criticism is also related to result dispersion due to the use of different types of equipment and execution procedures. The NSPT index depends on the amount of energy that is effectively transmitted to the sampler during the hammer fall. Thus, rational analyses of the SPT test results essentially depend on the estimation of this amount of energy. For this reason, several studies related to the energy involved in SPT test have been developed. This research presents interpretations of the SPT test results from the amounts of energy involved during the hammer fall. These amounts of energy are indirectly assessed by means of normal force and acceleration signals during the stress wave propagation along the string of rods. For this reason, a device that includes instrumentation capable of registering these signals of normal force and acceleration was developed. A series of tests was performed with the instrumentation installed at the top and the bottom of the string of rods. This arrangement allowed estimating the amount of energy available at the top and bottom of the string of rods. Thus, it was possible to estimate the efficiency of the SPT equipment basing on the amount of energy that actually reaches the sampler. From the recorded signals, it was also possible to assess the dynamic reaction force mobilized in the soil-sample system. The results were compared with other results obtained by theoretical methods, based on the Hamilton´s Principle, for evaluating the static and dynamic reaction force of the soil. These analyzes have shown that theoretical equations may be suitable for the determination of the soil strength, provided that the amount of energy that actually reaches the sampler be considered. Thus, these theoretical equations can be easily incorporated into the practice of foundation designs contributing to the development of methods based on the amount of energy required for the penetration of the sampler into the soil.
Alata, Rodriguez Jair Angelo, and Ninancuro Wilfredo Zevillanos. "Correlación entre el número de golpes N60 del Ensayo de Penetración Estándar y la Velocidad de ondas de corte (Vs) para los suelos arenosos del distrito de Juliaca – Puno." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/656163.
Full textThe application of the standard penetration test (SPT) entails a high level of detail, it is also expensive, requires qualified labor for its execution and is time-consuming; Its use is recommended in sandy soils, restrictive in fine and plastic soils and not recommended in other types of soils. While in the multichannel analysis of surface waves (MASW) its execution is not restricted, it allows covering large areas in short times, however, it is an indirect method, which is why its application must be verified by drilling, obtaining samples, and high analytical criteria. In recent years, the implementation and improvement of soil prospecting techniques has made it possible to carry out studies of the relationship of said tests with different soil parameters. In the present, an empirical correlation was developed between the SPT geotechnical tests by means of the number of penetration resistance blows (N60) with the value of the shear wave velocities (Vs) of the MASW geophysical tests, these tests were carried out in 30 points in the city of Juliaca for sandy soils. There was a final filter of 110 ordered pairs of data (Vs; N60); Through the analysis of potential regression by the method of least squares, the equation was obtained: Vs = 81.079*N600.2646; of the determination coefficient R2:0.76, it was determined that the correlation is acceptable. This equation was put into analysis and comparison with the equations of the correlations of the literature, in which it was found in a trend according to them.
Tesis
Reichmann, Markus. "Auslegung von Mikrowellen-Thermoprozess-Anlagen unter Nutzung von hochfrequenz-technischen Prinzipien." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2011. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-67409.
Full textLavoué, François. "Inversion des formes d'ondes électromagnétiques en 2D pour le géoradar : vers une imagerie multi-paramètre à partir des données de surface." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENU050/document.
Full textThe quantitative characterization of the shallow subsurface of the Earth is a critical issue for many environmental and societal challenges. Ground penetrating radar (GPR) is a geophysical method based on the propagation of electromagnetic waves for the prospection of the near subsurface. With central frequencies between 10~MHz and a few GHz, GPR covers a wide range of applications in geology, hydrology and civil engineering. GPR data are sensitive to variations in the electrical properties of the medium which can be related, for instance, to its water content and bring valuable information on hydrological processes. In this work, I develop a quantitative imaging method for the reconstruction of 2D distributions of permittivity and conductivity from GPR data acquired from the ground surface. The method makes use of the full waveform inversion technique (FWI), originating from seismic exploration, which exploits the entire recorded radargrams and has been proved successful in crosshole GPR applications.In a first time, I present the numerical forward modelling used to simulate the propagation of electromagnetic waves in 2D heterogeneous media and generate the synthetic GPR data that are compared to the recorded radargrams in the inversion process. A frequency-domain finite-difference algorithm originally developed in the visco-acoustic approximation is adapted to the electromagnetic problem in 2D via an acoustic-electromagnetic mathematical analogy.In a second time, the inversion scheme is formulated as a fully multiparameter optimization problem which is solved with the quasi-Newton L-BFGS algorithm. In this formulation, the effect of an approximate inverse Hessian is expected to mitigate the trade-off between the impact of permittivity and conductivity on the data. However, numerical tests on a synthetic benchmark of the literature display a large sensitivity of the method with respect to parameter scaling, showing the limits of the L-BFGS approximation. On a realistic subsurface benchmark with surface-to-surface configuration, it has been shown possible to ally parameter scaling and regularization to reconstruct 2D images of permittivity and conductivity without a priori assumptions.Finally, the imaging method is confronted to two real data sets. The consideration of laboratory-controlled data validates the proposed workflow for multiparameter imaging, as well as the accuracy of the numerical forward solutions. The application to on-ground GPR data acquired in a limestone massif is more challenging and necessitates a thorough investigation involving classical processing techniques and forward simulations. Starting permittivity models are derived from the velocity analysis of the direct arrivals and of the reflected events. The estimation of the source signature is performed together with an evaluation of an average conductivity value and of the unknown antenna height. In spite of this procedure, synthetic data do not reproduce the observed amplitudes, suggesting an effect of the radiation pattern of the shielded antennae. In preliminary tests, the inversion succeeds in fitting the data in the considered frequency range and can reconstruct reflectors from a smooth starting model
PIRIU, ANDREEA ALEXANDRA. "ESSAYS ON GLOBALISATION: EFFECTS AND IMPLICATIONS FOR INDIVIDUALS." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/728739.
Full textSudha, U. P. V. "Flutter Identification and Aeroelastic Stability during Wake Penetration." Thesis, 2015. https://etd.iisc.ac.in/handle/2005/4799.
Full textKe, Chuen-Jyi, and 柯春吉. "Measurement and Simulation of Wave Propagation and Penetration for Indoor Wireless Communications." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/93871736703336984898.
Full textLiu, Cangli. "I. Rigid body penetration into brittle materials. II. Phase change effect on shock wave propagation." Thesis, 1999. https://thesis.library.caltech.edu/7626/2/Liu_c_1999.pdf.
Full textPart I.
We have developed a technique for measuring the depth time history of rigid body penetration into brittle materials (hard rocks and concretes) under a deceleration of ~ 105 g. The technique includes bar-coded projectile, sabot-projectile separation, detection and recording systems. Because the technique can give very dense data on penetration depth time history, penetration velocity can be deduced. Error analysis shows that the technique has a small intrinsic error of ~ 3-4 % in time during penetration, and 0.3 to 0.7 mm in penetration depth. A series of 4140 steel projectile penetration into G-mixture mortar targets have been conducted using the Caltech 40 mm gas/ powder gun in the velocity range of 100 to 500 m/s.
We report, for the first time, the whole depth-time history of rigid body penetration into brittle materials (the G-mixture mortar) under 105 g deceleration. Based on the experimental results, including penetration depth time history, damage of recovered target and projectile materials and theoretical analysis, we find:
1. Target materials are damaged via compacting in the region in front of a projectile and via brittle radial and lateral crack propagation in the region surrounding the penetration path. The results suggest that expected cracks in front of penetrators may be stopped by a comminuted region that is induced by wave propagation. Aggregate erosion on the projectile lateral surface is < 20% of the final penetration depth. This result suggests that the effect of lateral friction on the penetration process can be ignored.
2. Final penetration depth, Pmax, is linearly scaled with initial projectile energy per unit cross-section area, es , when targets are intact after impact. Based on the experimental data on the mortar targets, the relation is Pmax(mm) 1.15es (J/mm2 ) + 16.39.
3. Estimation of the energy needed to create an unit penetration volume suggests that the average pressure acting on the target material during penetration is ~ 10 to 20 times higher than the unconfined strength of target materials under quasi-static loading, and 3 to 4 times higher than the possible highest pressure due to friction and material strength and its rate dependence. In addition, the experimental data show that the interaction between cracks and the target free surface significantly affects the penetration process.
4. Based on the fact that the penetration duration, tmax, increases slowly with es and does not depend on projectile radius approximately, the dependence of tmax on projectile length is suggested to be described by tmax(μs) = 2.08es (J/mm2 + 349.0 x m/(πR2), in which m is the projectile mass in grams and R is the projectile radius in mm. The prediction from this relation is in reasonable agreement with the experimental data for different projectile lengths.
5. Deduced penetration velocity time histories suggest that whole penetration history is divided into three stages: (1) An initial stage in which the projectile velocity change is small due to very small contact area between the projectile and target materials; (2) A steady penetration stage in which projectile velocity continues to decrease smoothly; (3) A penetration stop stage in which projectile deceleration jumps up when velocities are close to a critical value of ~ 35 m/s.
6. Deduced averaged deceleration, a, in the steady penetration stage for projectiles with same dimensions is found to be a(g) = 192.4v + 1.89 x 104, where v is initial projectile velocity in m/s. The average pressure acting on target materials during penetration is estimated to be very comparable to shock wave pressure.
7. A similarity of penetration process is found to be described by a relation between normalized penetration depth, P/Pmax, and normalized penetration time, t/tmax, as P/Pmax = f(t/tmax, where f is a function of t/tmax. After f(t/tmax is determined using experimental data for projectiles with 150 mm length, the penetration depth time history for projectiles with 100 mm length predicted by this relation is in good agreement with experimental data. This similarity also predicts that average deceleration increases with decreasing projectile length, that is verified by the experimental data.
8. Based on the penetration process analysis and the present data, a first principle model for rigid body penetration is suggested. The model incorporates the models for contact area between projectile and target materials, friction coefficient, penetration stop criterion, and normal stress on the projectile surface. The most important assumptions used in the model are: (1) The penetration process can be treated as a series of impact events, therefore, pressure normal to projectile surface is estimated using the Hugoniot relation of target material; (2) The necessary condition for penetration is that the pressure acting on target materials is not lower than the Hugoniot elastic limit; (3) The friction force on projectile lateral surface can be ignored due to cavitation during penetration. All the parameters involved in the model are determined based on independent experimental data. The penetration depth time histories predicted from the model are in good agreement with the experimental data.
9. Based on planar impact and previous quasi-static experimental data, the strain rate dependence of the mortar compressive strength is described by σf/σ0f = exp(0.0905(log(έ/έ_0) 1.14, in the strain rate range of 10-7/s to 103/s (σ0f and έ are reference compressive strength and strain rate, respectively). The non-dispersive Hugoniot elastic wave in the G-mixture has an amplitude of ~ 0.14 GPa and a velocity of ~ 4.3 km/s.
Part II.
Stress wave profiles in vitreous GeO2 were measured using piezoresistance gauges in the pressure range of 5 to 18 GPa under planar plate and spherical projectile impact. Experimental data show that the response of vitreous GeO2 to planar shock loading can be divided into three stages: (1) A ramp elastic precursor has peak amplitude of 4 GPa and peak particle velocity of 333 m/s. Wave velocity decreases from initial longitudinal elastic wave velocity of 3.5 km/s to 2.9 km/s at 4 GPa; (2) A ramp wave with amplitude of 2.11 GPa follows the precursor when peak loading pressure is 8.4 GPa. Wave velocity drops to the value below bulk wave velocity in this stage; (3) A shock wave achieving final shock state forms when peak pressure is > 6 GPa. The Hugoniot relation is D = 0.917 + 1.711u (km/s) using present data and the data of Jackson and Ahrens [1979] when shock wave pressure is between 6 and 40 GPa for ρ0 = 3.655 gj cm3 . Based on the present data, the phase change from 4-fold to 6-fold coordination of Ge+4 with O-2 in vitreous GeO2 occurs in the pressure range of 4 to 15 ± 1 GPa under planar shock loading. Comparison of the shock loading data for fused SiO2 to that on vitreous GeO2 demonstrates that transformation to the rutile structure in both media are similar. The Hugoniots of vitreous GeO2 and fused SiO2 are found to coincide approximately if pressure in fused SiO2 is scaled by the ratio of fused SiO2to vitreous GeO2 density. This result, as well as the same structure, provides the basis for considering vitreous Ge02 as an analogous material to fused SiO2 under shock loading. Experimental results from the spherical projectile impact demonstrate: (1) The supported elastic shock in fused SiO2 decays less rapidly than a linear elastic wave when elastic wave stress amplitude is higher than 4 GPa. The supported elastic shock in vitreous GeO2 decays faster than a linear elastic wave; (2) In vitreous GeO2 , unsupported shock waves decays with peak pressure in the phase transition range (4-15 GPa) with propagation distance, x, as α 1/x-3.35 , close to the prediction of Chen et al. [1998]. Based on a simple analysis on spherical wave propagation, we find that the different decay rates of a spherical elastic wave in fused SiO2 and vitreous GeO2 is predictable on the base of the compressibility variation with stress under one-dimensional strain condition in the two materials.
HUANG, PIN-SYUN, and 黃品勳. "Investigation of Ground Penetrating Radar Electromagnetic Wave Method to Inspect Pipeline Leaking." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/91724632880998771816.
Full text中華大學
土木工程學系
104
As time passes, an increasing number of buildings in Taiwan are characterized by old structures. In fact, there are more than three million old buildings in Taiwan. In addition, the country suffers from frequent earthquakes as it is situated at the boundary between the Philippine Sea Plate and Eurasian Sea Plate. Therefore, leakage is an inevitable problem in building structures. According to statistics, the majority reason for pipeline ruptures is loaded vibration, followed by corrosion of aging pipelines. Ninety percent of ruptured pipelines are PVC pipes. Using non-invasive ground-penetrating radars, this study detected internal leakage inside building structures. These radars excel in precision and convenience, and allow pipeline maintenance or replacement to be carried out with minimal excavation. This study employed the ground-penetrating radar’s 1 GHz probe to detect test leakages in pipes made of different materials buried in standard sand and PVC pipes in doubly reinforced concrete. The algorithm was applied to investigate real-life cases of leakages inside building structures. By using the basic theory of electromagnetic waves of ground-penetrating radars and by extracting and analyzing their digitized signals, observed variations in equivalent permittivity at the dry-wet interface were used to determine the area and source of leakage. These were rendered in 2D and 3D images to investigate the feasibility of such a method to detect leakages under different site conditions.
Lin, Tzu-Yao, and 林子堯. "Use of Ground Penetrating Radar Electromagnetic Wave Method for Detecting the Pipeline Leakage." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/71565008498977082214.
Full text中華大學
土木工程學系碩士班
102
This study uses the 1GHz ground penetrating radar(GPR) to inspect the leakage of the pipeline in sand and mortar with the rebar. The research applies the basic theory of electricmagnetic wave and digital signal acquisition technique to explore the equivalent relative dielectric constant changes of the Ottawa sand and cement mortar containing reinforcement under the situation of pipeline leakages. The experiment analyzes the related leakage signal characteristics and changes according to the electromagnetic wave reflections, time difference and equivalent relative dielectric constant. It then uses the difference of the equivalent relative dielectric constant of GPR in dry Ottawa sand and cement mortar material to determine the range of leakage distribution in the material.
Chu, Cheng-Tsai, and 朱澄財. "PENETRATIVE IMAGING OF 2D OBJECTS EMBEDDED IN LAYERED MEDIA BY MULTIFREQUENCY PLANE WAVE BACKWARD PROPAGATION." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/30779280203342869413.
Full text大同工學院
電機工程學系
84
In this thesis, the penetrative imaging of 2D objects embedded in layeredmedia under multifrequency plane waves illumination is being investigated. Weknow that the Green's function of a line source embedded in layered media can beformulated by using plane wave expansion. Here, the multifrequency plane wave backward propagation is being proposed based on the Green's function mensioned above. The FFT is applied on computation process of the Fourier transform,futher, it's employed in the computation of Green's function, penetrating fieldand image reconstruction. Besides, the performance of the penetrative imageunder the interference of uniform distributed random noise and multiple reflected field is also discussed. An experimental measurement is implemented accordingly. Finally, further developments for practical applications in nondestructive detection are forseen by the experimental results together with their simulations.
Wu, Ming-Tien, and 吳明典. "PENETRATIVE IMAGING OF OBJECTS EMBEDDED IN PLANAR MULTILAYER MEDIA BY MULTIFREQUENCY PLANE WAVE BACKWARD PROPAGATION." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/27443323857393841085.
Full text大同工學院
電機工程學系
84
ABSTRACT -- A penetrative imaging of 2D or 3D objects embedded in planar multilayer media is investigated under a multifrequency plane wave illumination. Both theoretical and experimental results are presented in this dissertation. A 3D multilayer Green''s function is derived in terms of plane wave superposition by using a 2D Fourier transform (FT). Based on this multilayer Green''s function, a penetrative imaging of 3D embedded objects can be expressed as multifrequency plane wave backward propagation. The 3D penetrative image can be reconstructed by a 2D inverse Fourier transform (IFT) on stacks of parallel planes, and the 2D penetrative imaging can be reconstructed by a 1D IFT on stacks of parallel lines. If the embedded objects are in the last layer, the penetrative imaging can be implemented with a 2D or 3D IFT for 2D and 3D cases, respectively. The penetrative imaging of both embedded conductors and dielectrics are demonstrated. Moreover, the performance of penetrative imaging with the random noise and the interference is discussed. An automatic measurement system is implemented for the penetrative imaging. Experimental results under various multilayer media and embedded objects are presented to demonstrate the performance of the imaging algorithm. The numerical and experimental results reveal that the proposed penetrative imaging can be applied to both the 2D and 3D embedded objects whether they are conductors or dielectrics. Besides, the method is insensitive to the high random noise and the high interference up to 100% of the peak of scattered field. Further developments into practical applications in non-destructive testing and underground detection are foreseen.
Chuang, Sheng-Cheng, and 莊聖正. "Utilization of Ground Penetrating Radar (Electromagnetic Wave)Method to Inspect The Embedded Pipe Leaking Problems." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/74985504760964501954.
Full text中華大學
土木工程學系碩士班
99
This study applied Ground Penetrating Radar of 1GHz against standard sand (Ottawa sand) with moisture that contained the bearing layer in different depths, and that contained pipeline leak’s experiment for the exploration. Based on the basic theory of electromagnetic wave (EM) and wave speed in connection with digital signal mining technique, the experiment processed non-destructive scanning with Ground Penetrating Radar of 1GHz to explore standard sand (Ottawa sand) with moisture that contained the bearing layer in different depths, and that contained pipeline leak. According to analysis of the relevant leak signal’s feature and change in electromagnetic wave (EM) reflected signal, waveform, time difference, frequency spectrum properties, wave speed and relative permittivity constants, etc. of electromagnetic wave (EM), it is concluded that the corresponding relationship between electromagnetic wave (EM) of Ground Penetrating Radar and leak in the standard sand, suggesting to detach dry-wet sand interface by using time difference in electromagnetic wave (EM) speed of Ground Penetrating Radar, and establishing a judgment method for leak range and leak source.
Chen, Yu-Tien, and 陳裕典. "Using an electromagnetic wave to pursue corrosion of steel (rebars) within concrete by Ground Penetrating Radar." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/55995971060050459127.
Full textPASCALE, VINCENZO. "Smart antennas for strategic environment." Doctoral thesis, 2016. http://hdl.handle.net/11573/925084.
Full textJhang, ying-min, and 張英旻. "Make use of the ground-penetrating radar and electromagnetic wave image handle a technique to the road pipeline probes into its research." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/50373716314340136733.
Full text國立中央大學
土木工程研究所
95
The times in fast variety, people work to always hope fast and then valid, had better can also save expense in addition, deeply the land mine attain a method opposite open to dig in the clear ditch, ground-penetrating radar to explore, obvious since quick and again save expense, in the civil engineering in carry on in the city underground open to dig to usually concern the problem of underground pipeline, if can not control a pipeline to lay position correctly in times before, will cause to construct in the engineering in the days to come last inconvenience and risk, and if adopt traditional clear ditch to open the way for digging to bring about greater influence on transportation easily, and not agree with to match an economic benefit.High Pin ground-penetrating radar deeply the land mine attain to have a high resolution, the signal repetition is high, and tests a fast advantage. So adoption fast, the economy is high of nondestructive evaluation way concert the related data take in to judge, is already the trend of future development, in order to being easily subjected to direct wave rather great influence when the time area measurement''s analysis reflect a signal, often cause shallow layer signal easily with direct wave mutual interference and hard discretion.This research mainly experiments through the school and now experiment, understand the signal characteristic of radar wave, again through behind handle of way, improve deeply land mine to attain of signal. According to the analytical result manifestation of the experimenting of school and scene, behind handle program ability will direct wave signal with keep on the existent background noise clean, having further control to the analysis that need to be measured a thing signal and the judgment.
Ramli, Khairun N., Raed A. Abd-Alhameed, Hmeda I. Hraga, D. T. W. Liang, and Peter S. Excell. "Electromagnetic Field Interaction Between Overhead High Voltage Power Transmission Line and Buried Utility Pipeline." 2011. http://hdl.handle.net/10454/5468.
Full textThis work presents the development of a new approach of modelling the source excitation and the penetration of structures by continuous propagating electromagnetic (EM) plane waves. The technique incorporates the solution of time-dependent Maxwell¿s equations and the initial value problem as the structures are illuminated by the plane waves. The propagation of waves from source excitation is simulated by solving a finite-difference Maxwell's equation in the time domain. Subgridding method is used to condense the lattice at the point of interest locally for observing field distribution in high resolution. The computational burden due to huge number of time steps has been eased by employing quasi-static approach. An example of induced EM fields near an underground pipeline runs parallel to a 132 kV overhead power transmission line (OHTL) has been presented which paves the way in the development of new approach of EM fields interaction modelling.
MSCRC
Samui, Pijush. "Geotechnical Site Characterization And Liquefaction Evaluation Using Intelligent Models." Thesis, 2009. https://etd.iisc.ac.in/handle/2005/628.
Full textSamui, Pijush. "Geotechnical Site Characterization And Liquefaction Evaluation Using Intelligent Models." Thesis, 2009. http://hdl.handle.net/2005/628.
Full textReichmann, Markus. "Auslegung von Mikrowellen-Thermoprozess-Anlagen unter Nutzung von hochfrequenz-technischen Prinzipien: am Beispiel eines Entbinderungsofens für keramische Grünkörper." Doctoral thesis, 2010. https://tubaf.qucosa.de/id/qucosa%3A22757.
Full textAbhishek, Kumar *. "Seismic Microzonation Of Lucknow Based On Region Specific GMPE's And Geotechnical Field Studies." Thesis, 2012. https://etd.iisc.ac.in/handle/2005/2559.
Full textAbhishek, Kumar *. "Seismic Microzonation Of Lucknow Based On Region Specific GMPE's And Geotechnical Field Studies." Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2559.
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