The objective of this paper is to study how the selection of the coil and the frequency affects the received modes in
guided Lamb waves, with the objective of analyzing the best configuration for determining the depth of a given
defect in a metallic pipe with the minimum error. Studies of the size of the damages with all the extracted
parameters are then used to propose estimators of the residual thickness, considering amplitude and phase
information in one or several modes. Results demonstrate the suitability of the proposal, improving the estimation of
the residual thickness when two simultaneous modes are used, as well as the range of possibilities that the coil and
frequency selection offers.
Pseudoperiodic waveguides with selection of spatial harmonics and modesVictor Solntsev
A principle of selection of modes and their spatial harmonics in periodic waveguides and, in particular, in spatially developed slowing systems for multibeam traveling-wave tubes (TWTs) is elaborated. The essence of the principle is in the following: varying along the length of the system its period and at least one more parameter that determines the phase shift per period, one can provide constant phase velocity of one spatial harmonic and destroy other spatial harmonics, i.e., reduce their amplitudes substantially. In this case, variations of the period may be significant, and the slowing system becomes nonuniform, or pseudoperiodic; namely, one of the spatial harmonics remains the same as in the initial periodic structure. Relationships are derived for the amplitudes of the spatial-wave harmonics, interaction coefficient, and coupling impedance of the pseudoperiodic system. The possibility of the mode selection in pseudoperiodic slowing systems when the synchronism condition is satisfied for the spatial harmonic of one mode is investigated. The efficiency of suppressing spurious spatial harmonics and modes for linear and abrupt variation of spacing is estimated. The elaborated principle of selection of spatial harmonics and modes is illustrated by an example of a two-section helical-waveguide slowing system.
PROPAGACIÓN DE ONDAS ARMONICAS TRANSVERSALES EN UNA CUERDA TENSADaniel A. Lopez Ch.
This document summarizes an experiment to study the linear density of a tense string. Vibrations were produced in a string with constant voltage and tension. Two methods were used to calculate the linear density. The first method found a linear density of 266.56 kg/m by averaging, while the second method found 152.052 kg/m by graphing wavelength versus period. Both results differed from the theoretical linear density without tension. The experiment demonstrated the inverse relationship between frequency and wavelength for stationary waves in a tense string.
This document contains a 47 question physics exam with multiple choice answers. It covers topics like electromagnetism, mechanics, optics, modern physics, and digital electronics. The questions test concepts like magnetic fields, capacitors, transformers, waves, quantum mechanics, radioactivity, and logic gates.
1. Physics deals with matter and energy through defining and characterizing interactions between the two.
2. Mechanics studies motion and forces, including quantities like speed, velocity, acceleration, force, momentum and Newton's Laws of Motion.
3. Solving physics problems involves identifying known and unknown quantities, selecting the appropriate equation, and using the correct units.
This document summarizes a research article that develops a theoretical model to describe how decoherence effects rubidium vapor in an electromagnetically induced transparency (EIT) experiment. The model accounts for decoherence from both dephasing and population relaxation. It quantifies the impact of decoherence on various experimental measurements, including Faraday rotation, susceptibility, transmission, and coherence relationships. The model is in good agreement with previous experimental results. It also discusses how the model could be applied to other EIT-based experiments and how Faraday rotation could be used to detect single atoms.
1. The document provides conceptual problems and solutions related to superposition and standing waves. It discusses topics like wave pulses traveling in opposite directions, fundamental frequencies of open and closed organ pipes, and using resonance frequencies to estimate air temperature.
2. It also covers problems involving interference of two waves with different phases and frequencies, and deriving an expression for the envelope of a superposed wave.
3. For one problem, it plots the total displacement of a superposed wave at t=0, and the envelope function at t=0, 5, and 10 seconds. From these plots, it estimates the speed of the envelope and compares it to the theoretical value obtained from the problem parameters.
First and second order semi-Markov chains for wind speed modelingNozir Shokirov
An overview of Guglelmo D'Amic et al. paper titled as "First and second order semi-Markov chains for wind speed modeling" from the journal of Physica A 2012.
Learning Object- Standing Waves on Stringskendrick24
This is my learning object about standing waves on a string. I talk about the harmonics, the equation for calculating the frequency for a wave on a string, and gave an example problem.
Pseudoperiodic waveguides with selection of spatial harmonics and modesVictor Solntsev
A principle of selection of modes and their spatial harmonics in periodic waveguides and, in particular, in spatially developed slowing systems for multibeam traveling-wave tubes (TWTs) is elaborated. The essence of the principle is in the following: varying along the length of the system its period and at least one more parameter that determines the phase shift per period, one can provide constant phase velocity of one spatial harmonic and destroy other spatial harmonics, i.e., reduce their amplitudes substantially. In this case, variations of the period may be significant, and the slowing system becomes nonuniform, or pseudoperiodic; namely, one of the spatial harmonics remains the same as in the initial periodic structure. Relationships are derived for the amplitudes of the spatial-wave harmonics, interaction coefficient, and coupling impedance of the pseudoperiodic system. The possibility of the mode selection in pseudoperiodic slowing systems when the synchronism condition is satisfied for the spatial harmonic of one mode is investigated. The efficiency of suppressing spurious spatial harmonics and modes for linear and abrupt variation of spacing is estimated. The elaborated principle of selection of spatial harmonics and modes is illustrated by an example of a two-section helical-waveguide slowing system.
PROPAGACIÓN DE ONDAS ARMONICAS TRANSVERSALES EN UNA CUERDA TENSADaniel A. Lopez Ch.
This document summarizes an experiment to study the linear density of a tense string. Vibrations were produced in a string with constant voltage and tension. Two methods were used to calculate the linear density. The first method found a linear density of 266.56 kg/m by averaging, while the second method found 152.052 kg/m by graphing wavelength versus period. Both results differed from the theoretical linear density without tension. The experiment demonstrated the inverse relationship between frequency and wavelength for stationary waves in a tense string.
This document contains a 47 question physics exam with multiple choice answers. It covers topics like electromagnetism, mechanics, optics, modern physics, and digital electronics. The questions test concepts like magnetic fields, capacitors, transformers, waves, quantum mechanics, radioactivity, and logic gates.
1. Physics deals with matter and energy through defining and characterizing interactions between the two.
2. Mechanics studies motion and forces, including quantities like speed, velocity, acceleration, force, momentum and Newton's Laws of Motion.
3. Solving physics problems involves identifying known and unknown quantities, selecting the appropriate equation, and using the correct units.
This document summarizes a research article that develops a theoretical model to describe how decoherence effects rubidium vapor in an electromagnetically induced transparency (EIT) experiment. The model accounts for decoherence from both dephasing and population relaxation. It quantifies the impact of decoherence on various experimental measurements, including Faraday rotation, susceptibility, transmission, and coherence relationships. The model is in good agreement with previous experimental results. It also discusses how the model could be applied to other EIT-based experiments and how Faraday rotation could be used to detect single atoms.
1. The document provides conceptual problems and solutions related to superposition and standing waves. It discusses topics like wave pulses traveling in opposite directions, fundamental frequencies of open and closed organ pipes, and using resonance frequencies to estimate air temperature.
2. It also covers problems involving interference of two waves with different phases and frequencies, and deriving an expression for the envelope of a superposed wave.
3. For one problem, it plots the total displacement of a superposed wave at t=0, and the envelope function at t=0, 5, and 10 seconds. From these plots, it estimates the speed of the envelope and compares it to the theoretical value obtained from the problem parameters.
First and second order semi-Markov chains for wind speed modelingNozir Shokirov
An overview of Guglelmo D'Amic et al. paper titled as "First and second order semi-Markov chains for wind speed modeling" from the journal of Physica A 2012.
Learning Object- Standing Waves on Stringskendrick24
This is my learning object about standing waves on a string. I talk about the harmonics, the equation for calculating the frequency for a wave on a string, and gave an example problem.
Spatially adiabatic frequency conversion in opto-electro-mechanical arraysOndrej Cernotik
Optoelectromechanical systems offer a promising route towards frequency conversion between microwaves and light and towards building quantum networks of superconducting circuits. Current theoretical and experimental efforts focus on approaches based on either optomechanically induced transparency or adiabatic passage. The former has the advantage of working with time-independent control but only in a limited bandwidth (typically much smaller than the cavity linewidth); the latter can, in principle, be used to increase the bandwidth but at the expense of working with time-dependent control fields and with strong optomechanical coupling. In my presentation, I will show that an array of optoelectromechanical transducers can overcome this limitation and reach a bandwidth that is larger than the cavity linewidth. The coupling rates are varied in space throughout the array so that a mechanically dark mode of the propagating fields adiabatically changes from microwave to optical or vice versa. This strategy also leads to significantly reduced thermal noise with the collective optomechanical cooperativity being the relevant figure of merit. I will also demonstrate that, remarkably, the bandwidth enhancement per transducer element is largest for small arrays. With these features the scheme is particularly relevant for improving the conversion bandwidth in state-of-the-art experimental setups.
(1) The document provides conceptual problems and their solutions related to oscillations and simple harmonic motion. (2) It examines the kinetic and potential energy of an object undergoing simple harmonic motion with a given amplitude. (3) It compares the maximum speeds of two simple harmonic oscillators with identical amplitudes but different masses attached to identical springs.
This document describes the design and analysis of a quarter-wave transmission line and a single-stub transmission line. It provides the initial parameters and equations used to design the transmission lines. Graphs of standing wave ratio (SWR) versus normalized frequency are generated for each type of transmission line using MATLAB. The bandwidths of the transmission lines are then calculated and compared based on the SWR graphs. Key findings include the quarter-wave transmission line having a more consistent SWR and bandwidth, while the single-stub transmission line has a higher chance of fully reflecting signals back to the generator.
This paper was published by my former Supervisor and involves partly my calculations and the concepts used during my MSci Thesis at University College London.
1) The document surveys methods for detecting, isolating, and identifying robot collisions using only proprioceptive sensors.
2) It describes several methods including using estimates of total energy, generalized momentum, joint acceleration, and inverse dynamics. Computational issues with each method are also discussed.
3) Experimental results applying the methods to various robot platforms like a humanoid and Kuka are presented, demonstrating the ability to detect and locate collisions using only internal sensors.
This document summarizes research on two-dimensional solid-state nutation NMR experiments for determining quadrupole parameters of half-integer quadrupolar nuclei. It presents:
1) A complete series of simulated nutation spectra for spins I = 3/2 to I = 5 calculated using density matrix formalism to serve as fingerprints for parameter determination.
2) Applications of the method to 27Al in spodumene and 45Sc in Sc2(SO4)3 to determine their quadrupole parameters by comparing experimental spectra to simulations.
3) Discussion of experimental aspects like resonance offset and magic angle spinning and how they affect the nutation spectra.
Simulation of Nonstationary Processes in Backward-Wave Tube with the Self-Mod...Victor Solntsev
The equations that describe nonlinear nonstationary processes in carcinotrode (backward- wave tube with the emission modulation in the presence of the field of the output signal fed to the cathode via a feedback loop) are derived. An algorithm and the corresponding code are developed to solve the equations with allowance for the modulation of emission using nonuniform (with respect to time) large particles (electrons of equal charge) ejected from the cathode. The effect of the feedback parameter on the intensity and shape of the carcinotrode oscillations is analyzed. It is demonstrated that the carcinotrode efficiency can be increased to about 50% upon the generation of harmonic oscil- lations. A more significant increase in the efficiency to 70% is possible in the regime of the weak self- modulation of oscillations upon an increase in the feedback coefficient in the feedback loop involving the slow-wave structure and the cathode and a decrease in the cathode–grid static field.
Standing waves can be described by the equation D(x,t) = 2A sin(kx) cos (ωt). Nodes occur where the amplitude is zero and antinodes where it is maximum. On a vibrating string, the wavelength is determined by the length of the string and tension. The fundamental frequency produces the longest wavelength with no nodes. Higher harmonics have shorter wavelengths and more nodes. Examples calculate the frequency of a guitar string at different tensions and lengths of the standing wave where the amplitude is a given value.
Research on Transformer Core Vibration under DC Bias Based on Multi-field Cou...inventionjournals
The Mathematical models for DC bias vibration analysis of the transformer core are developed in this paper. The model is combined into multi-physical field coupling modeling for vibration analysis of the transformer. By applying the primary voltage as excitation and under different DC bias, vibrations of the transformer core is simulated and analyzed.
This document provides an introduction to quantum mechanics concepts including:
1. It describes Schrodinger's wave equation and its applications, including quantized energy levels and tunneling effects.
2. Wave-particle duality is discussed through experiments demonstrating the wave-like and particle-like properties of electrons.
3. The uncertainty principle and solutions to Schrodinger's wave equation for simple potential wells are presented, showing energy levels are quantized.
applications of second order differential equationsly infinitryx
1) Second-order differential equations are used to model vibrating springs and electric circuits. They describe oscillations, vibrations, and resonance.
2) Springs obey Hooke's law, resulting in a second-order differential equation relating position to time. The solutions describe simple harmonic motion.
3) Damping forces can be added, resulting in overdamped, critically damped, or underdamped systems with different behavior.
The document discusses recent calculations of impulsive stimulated Raman transitions in atoms using the LBNL-AMO-MCTDHF method. It provides background on the MCTDHF (Multiconfiguration Time-Dependent Hartree-Fock) method, which allows for nonperturbative calculations of electronic dynamics in molecules interacting with intense pulses. The author surveys stimulated Raman transitions between s-wave ground states of different atoms, finding that population transfer is maximized to final s-states rather than d-states. Hypotheses for improving population transfer using circularly polarized pulses are discussed.
This document contains 50 physics problems from an unsolved past exam paper from 2008. The problems cover a range of topics including mechanics, waves, optics, electricity, magnetism, modern physics and thermodynamics. For each problem, four multiple choice answers are provided and the correct answer is to be indicated by writing the letter a, b, c or d. The problems involve calculations of quantities such as acceleration, velocity, energy, time period, wavelength and more.
This document provides an overview of a molecular modeling course schedule and topics. The course will cover molecular properties, surfaces, electrostatics, electron microscopy, crystallography, NMR, molecular mechanics, sequence to structure relationships, visualization, molecular dynamics, ligand parameterization, and drug design. Key dates include a homework deadline of January 15th and a final exam on January 22nd. The instructor will discuss topics like classical forcefields, molecular dynamics simulations, solvation models, and hands-on exercises.
A generalized linear theory of the discrete electron–wave interaction in slow...Victor Solntsev
A linear theory of the discrete interaction of electron flows and electromagnetic waves in slow-wave structures (SWSs) is developed. The theory is based on the finite-difference equations of SWS excitation. The local coupling impedance entering these equations characterizes the field intensity excited by the electron flow in interaction gaps and has a finite value at SWS cutoff frequencies. The theory uniformly describes the electron–wave interaction in SWS passbands and stopbands without using equivalent circuits, a circumstance that allows considering the processes in the vicinity of cutoff frequencies and switching from the Cerenkov mechanism of interaction in a traveling-wave tube to the klystron mechanism when passing to SWS stopbands. The features of the equations of the discrete electron–wave interaction in pseudoperiodic SWSs are analyzed.
Quantum Theory. Wave Particle Duality. Particle in a Box. Schrodinger wave equation. Quantum Numbers and Electron Orbitals. Principal Shells and Subshells. A Fourth Quantum Number. Effective nuclear charge
This experiment investigated the relationship between the length of a straw tube and the wavelength of standing sound waves produced within the tube. Various length straw tubes were blown to produce sound, and the frequencies of the standing waves were measured. The data showed a linear relationship between length and wavelength, but the slope did not match predictions. Sources of error were noises detected by the microphone and variability in blowing the straw. Improving controls and collecting data over a wider range of lengths could increase the accuracy of results.
This document covers various topics related to waves including different types of waves, wave properties such as amplitude and wavelength, and concepts such as superposition, reflection, and standing waves. It discusses transverse and longitudinal waves, the displacement relation for progressive waves, and formulas for the speed of sound and waves on strings. Reflection at closed and open boundaries is examined, showing how the
This document presents a novel algorithm for classifying signals (glitches) that arise in gravitational wave channels of the Laser Interferometer Gravitational-Wave Observatory (LIGO). The algorithm uses Kohonen Self Organizing Feature Maps and discrete wavelet transform coefficients to classify glitches based on their morphology and other parameters like signal-to-noise ratio and duration. This low-latency algorithm aims to help the LIGO detector characterization group identify and mitigate noise sources more quickly.
The document discusses single carrier transmission using LabVIEW & NI-USRP. It covers several topics:
1. Symbol synchronization using the maximum output energy solution which introduces an adaptive element to find the optimal sampling time that maximizes output power.
2. The role of pseudo-noise sequences in frame synchronization, which provide properties like balance and unpredictability needed for random sequences.
3. The Moose algorithm for carrier frequency offset estimation and correction which exploits least squares to determine the phase shift between training sequences and correct sample phases.
4. The effects of multipath propagation including fading caused by constructive/destructive interference from multiple propagation paths, and intersymbol interference when path delays cause symbol interference.
The document discusses single carrier transmission using LabVIEW & NI-USRP. It covers several topics:
1. Symbol synchronization using the maximum output energy solution which introduces an adaptive element to find the optimal sampling time that maximizes output power.
2. The role of pseudo-noise sequences in frame synchronization, which provide properties like balance and unpredictability needed for random sequences.
3. The Moose algorithm for carrier frequency offset estimation and correction which exploits least squares to determine the phase shift between training sequences and correct sample phases.
4. The effects of multipath propagation including fading caused by constructive/destructive interference from multiple propagation paths, and intersymbol interference when path delays cause symbol interference.
Smart Sound Processing for Defect Sizing in Pipelines Using EMAT Actuator Bas...Innerspec Technologies
Pipeline inspection is a topic of particular interest to the companies. Especially important is the defect sizing, which allows them to avoid subsequent costly repairs in their equipment. A solution for this issue is using ultrasonic waves sensed through Electro-Magnetic Acoustic Transducer (EMAT)
actuators. The main advantage of this technology is the absence of the need to have direct contact with the surface of the material under investigation, which must be a conductive one. Specifically interesting is the meander-line-coil based Lamb wave generation, since the directivity of the waves allows a study based in the circumferential wrap-around received signal. However, the variety of defect sizes changes the behavior of the signal when it passes through the pipeline. Because of that, it is necessary to apply advanced techniques based on Smart Sound Processing (SSP). These methods involve extracting useful information from the signals sensed with EMAT at different frequencies to obtain nonlinear estimations of the depth of the defect, and to select the features that better estimate the profile of the pipeline. The proposed technique has been tested using both simulated and real signals in steel pipelines, obtaining good results in terms of Root Mean Square Error (RMSE).
Spatially adiabatic frequency conversion in opto-electro-mechanical arraysOndrej Cernotik
Optoelectromechanical systems offer a promising route towards frequency conversion between microwaves and light and towards building quantum networks of superconducting circuits. Current theoretical and experimental efforts focus on approaches based on either optomechanically induced transparency or adiabatic passage. The former has the advantage of working with time-independent control but only in a limited bandwidth (typically much smaller than the cavity linewidth); the latter can, in principle, be used to increase the bandwidth but at the expense of working with time-dependent control fields and with strong optomechanical coupling. In my presentation, I will show that an array of optoelectromechanical transducers can overcome this limitation and reach a bandwidth that is larger than the cavity linewidth. The coupling rates are varied in space throughout the array so that a mechanically dark mode of the propagating fields adiabatically changes from microwave to optical or vice versa. This strategy also leads to significantly reduced thermal noise with the collective optomechanical cooperativity being the relevant figure of merit. I will also demonstrate that, remarkably, the bandwidth enhancement per transducer element is largest for small arrays. With these features the scheme is particularly relevant for improving the conversion bandwidth in state-of-the-art experimental setups.
(1) The document provides conceptual problems and their solutions related to oscillations and simple harmonic motion. (2) It examines the kinetic and potential energy of an object undergoing simple harmonic motion with a given amplitude. (3) It compares the maximum speeds of two simple harmonic oscillators with identical amplitudes but different masses attached to identical springs.
This document describes the design and analysis of a quarter-wave transmission line and a single-stub transmission line. It provides the initial parameters and equations used to design the transmission lines. Graphs of standing wave ratio (SWR) versus normalized frequency are generated for each type of transmission line using MATLAB. The bandwidths of the transmission lines are then calculated and compared based on the SWR graphs. Key findings include the quarter-wave transmission line having a more consistent SWR and bandwidth, while the single-stub transmission line has a higher chance of fully reflecting signals back to the generator.
This paper was published by my former Supervisor and involves partly my calculations and the concepts used during my MSci Thesis at University College London.
1) The document surveys methods for detecting, isolating, and identifying robot collisions using only proprioceptive sensors.
2) It describes several methods including using estimates of total energy, generalized momentum, joint acceleration, and inverse dynamics. Computational issues with each method are also discussed.
3) Experimental results applying the methods to various robot platforms like a humanoid and Kuka are presented, demonstrating the ability to detect and locate collisions using only internal sensors.
This document summarizes research on two-dimensional solid-state nutation NMR experiments for determining quadrupole parameters of half-integer quadrupolar nuclei. It presents:
1) A complete series of simulated nutation spectra for spins I = 3/2 to I = 5 calculated using density matrix formalism to serve as fingerprints for parameter determination.
2) Applications of the method to 27Al in spodumene and 45Sc in Sc2(SO4)3 to determine their quadrupole parameters by comparing experimental spectra to simulations.
3) Discussion of experimental aspects like resonance offset and magic angle spinning and how they affect the nutation spectra.
Simulation of Nonstationary Processes in Backward-Wave Tube with the Self-Mod...Victor Solntsev
The equations that describe nonlinear nonstationary processes in carcinotrode (backward- wave tube with the emission modulation in the presence of the field of the output signal fed to the cathode via a feedback loop) are derived. An algorithm and the corresponding code are developed to solve the equations with allowance for the modulation of emission using nonuniform (with respect to time) large particles (electrons of equal charge) ejected from the cathode. The effect of the feedback parameter on the intensity and shape of the carcinotrode oscillations is analyzed. It is demonstrated that the carcinotrode efficiency can be increased to about 50% upon the generation of harmonic oscil- lations. A more significant increase in the efficiency to 70% is possible in the regime of the weak self- modulation of oscillations upon an increase in the feedback coefficient in the feedback loop involving the slow-wave structure and the cathode and a decrease in the cathode–grid static field.
Standing waves can be described by the equation D(x,t) = 2A sin(kx) cos (ωt). Nodes occur where the amplitude is zero and antinodes where it is maximum. On a vibrating string, the wavelength is determined by the length of the string and tension. The fundamental frequency produces the longest wavelength with no nodes. Higher harmonics have shorter wavelengths and more nodes. Examples calculate the frequency of a guitar string at different tensions and lengths of the standing wave where the amplitude is a given value.
Research on Transformer Core Vibration under DC Bias Based on Multi-field Cou...inventionjournals
The Mathematical models for DC bias vibration analysis of the transformer core are developed in this paper. The model is combined into multi-physical field coupling modeling for vibration analysis of the transformer. By applying the primary voltage as excitation and under different DC bias, vibrations of the transformer core is simulated and analyzed.
This document provides an introduction to quantum mechanics concepts including:
1. It describes Schrodinger's wave equation and its applications, including quantized energy levels and tunneling effects.
2. Wave-particle duality is discussed through experiments demonstrating the wave-like and particle-like properties of electrons.
3. The uncertainty principle and solutions to Schrodinger's wave equation for simple potential wells are presented, showing energy levels are quantized.
applications of second order differential equationsly infinitryx
1) Second-order differential equations are used to model vibrating springs and electric circuits. They describe oscillations, vibrations, and resonance.
2) Springs obey Hooke's law, resulting in a second-order differential equation relating position to time. The solutions describe simple harmonic motion.
3) Damping forces can be added, resulting in overdamped, critically damped, or underdamped systems with different behavior.
The document discusses recent calculations of impulsive stimulated Raman transitions in atoms using the LBNL-AMO-MCTDHF method. It provides background on the MCTDHF (Multiconfiguration Time-Dependent Hartree-Fock) method, which allows for nonperturbative calculations of electronic dynamics in molecules interacting with intense pulses. The author surveys stimulated Raman transitions between s-wave ground states of different atoms, finding that population transfer is maximized to final s-states rather than d-states. Hypotheses for improving population transfer using circularly polarized pulses are discussed.
This document contains 50 physics problems from an unsolved past exam paper from 2008. The problems cover a range of topics including mechanics, waves, optics, electricity, magnetism, modern physics and thermodynamics. For each problem, four multiple choice answers are provided and the correct answer is to be indicated by writing the letter a, b, c or d. The problems involve calculations of quantities such as acceleration, velocity, energy, time period, wavelength and more.
This document provides an overview of a molecular modeling course schedule and topics. The course will cover molecular properties, surfaces, electrostatics, electron microscopy, crystallography, NMR, molecular mechanics, sequence to structure relationships, visualization, molecular dynamics, ligand parameterization, and drug design. Key dates include a homework deadline of January 15th and a final exam on January 22nd. The instructor will discuss topics like classical forcefields, molecular dynamics simulations, solvation models, and hands-on exercises.
A generalized linear theory of the discrete electron–wave interaction in slow...Victor Solntsev
A linear theory of the discrete interaction of electron flows and electromagnetic waves in slow-wave structures (SWSs) is developed. The theory is based on the finite-difference equations of SWS excitation. The local coupling impedance entering these equations characterizes the field intensity excited by the electron flow in interaction gaps and has a finite value at SWS cutoff frequencies. The theory uniformly describes the electron–wave interaction in SWS passbands and stopbands without using equivalent circuits, a circumstance that allows considering the processes in the vicinity of cutoff frequencies and switching from the Cerenkov mechanism of interaction in a traveling-wave tube to the klystron mechanism when passing to SWS stopbands. The features of the equations of the discrete electron–wave interaction in pseudoperiodic SWSs are analyzed.
Quantum Theory. Wave Particle Duality. Particle in a Box. Schrodinger wave equation. Quantum Numbers and Electron Orbitals. Principal Shells and Subshells. A Fourth Quantum Number. Effective nuclear charge
This experiment investigated the relationship between the length of a straw tube and the wavelength of standing sound waves produced within the tube. Various length straw tubes were blown to produce sound, and the frequencies of the standing waves were measured. The data showed a linear relationship between length and wavelength, but the slope did not match predictions. Sources of error were noises detected by the microphone and variability in blowing the straw. Improving controls and collecting data over a wider range of lengths could increase the accuracy of results.
This document covers various topics related to waves including different types of waves, wave properties such as amplitude and wavelength, and concepts such as superposition, reflection, and standing waves. It discusses transverse and longitudinal waves, the displacement relation for progressive waves, and formulas for the speed of sound and waves on strings. Reflection at closed and open boundaries is examined, showing how the
This document presents a novel algorithm for classifying signals (glitches) that arise in gravitational wave channels of the Laser Interferometer Gravitational-Wave Observatory (LIGO). The algorithm uses Kohonen Self Organizing Feature Maps and discrete wavelet transform coefficients to classify glitches based on their morphology and other parameters like signal-to-noise ratio and duration. This low-latency algorithm aims to help the LIGO detector characterization group identify and mitigate noise sources more quickly.
The document discusses single carrier transmission using LabVIEW & NI-USRP. It covers several topics:
1. Symbol synchronization using the maximum output energy solution which introduces an adaptive element to find the optimal sampling time that maximizes output power.
2. The role of pseudo-noise sequences in frame synchronization, which provide properties like balance and unpredictability needed for random sequences.
3. The Moose algorithm for carrier frequency offset estimation and correction which exploits least squares to determine the phase shift between training sequences and correct sample phases.
4. The effects of multipath propagation including fading caused by constructive/destructive interference from multiple propagation paths, and intersymbol interference when path delays cause symbol interference.
The document discusses single carrier transmission using LabVIEW & NI-USRP. It covers several topics:
1. Symbol synchronization using the maximum output energy solution which introduces an adaptive element to find the optimal sampling time that maximizes output power.
2. The role of pseudo-noise sequences in frame synchronization, which provide properties like balance and unpredictability needed for random sequences.
3. The Moose algorithm for carrier frequency offset estimation and correction which exploits least squares to determine the phase shift between training sequences and correct sample phases.
4. The effects of multipath propagation including fading caused by constructive/destructive interference from multiple propagation paths, and intersymbol interference when path delays cause symbol interference.
Smart Sound Processing for Defect Sizing in Pipelines Using EMAT Actuator Bas...Innerspec Technologies
Pipeline inspection is a topic of particular interest to the companies. Especially important is the defect sizing, which allows them to avoid subsequent costly repairs in their equipment. A solution for this issue is using ultrasonic waves sensed through Electro-Magnetic Acoustic Transducer (EMAT)
actuators. The main advantage of this technology is the absence of the need to have direct contact with the surface of the material under investigation, which must be a conductive one. Specifically interesting is the meander-line-coil based Lamb wave generation, since the directivity of the waves allows a study based in the circumferential wrap-around received signal. However, the variety of defect sizes changes the behavior of the signal when it passes through the pipeline. Because of that, it is necessary to apply advanced techniques based on Smart Sound Processing (SSP). These methods involve extracting useful information from the signals sensed with EMAT at different frequencies to obtain nonlinear estimations of the depth of the defect, and to select the features that better estimate the profile of the pipeline. The proposed technique has been tested using both simulated and real signals in steel pipelines, obtaining good results in terms of Root Mean Square Error (RMSE).
In metallurgy, cladding refers to the bonding together of dissimilar metals, normally achieved by extruding two or more metals through a die or pressing sheets together under high pressure. Timely detection of delamination that occurs occasionally during the cladding processes is very important for the industry. This paper presents an EMAT system based on ultrasonic guided wave techniques. The analysis of a three-layer, brass/copper/brass product is also presented including dispersion curves, and interaction of ultrasonic guided wave with delamination defects. The authors observed a cyclic behavior of guided wave propagation with the increase of defect size. An explanation is introduced and proved with finite element analysis. The results presented in this paper will have a very significant impact on understanding of delamination detection in multilayered composite structures including adhesive bonded structures.
This document proposes and analyzes a system for generating continuous variable quantum codes using nonlinear microring resonators (NMRRs). Optical solitons or Gaussian pulses propagating in the NMRRs induce chaotic behavior and generate large bandwidth signals suitable for high channel capacity quantum communication. The system uses multiple cascaded NMRRs along with a polarization controller and beam splitter to generate distinguished up and down optical soliton link pulses. Simulations show the system can obtain specific frequency bands and wavelengths for quantum key distribution applications by controlling the NMRR parameters.
1. Microwave diagnostics techniques such as interferometry, reflectometry, scattering and electron cyclotron emission (ECE) have been powerful tools for diagnosing magnetically confined plasmas.
2. Recent advances in electronics and computer technology have enabled the development of advanced microwave diagnostic systems that can measure 2D and 3D profiles of plasma density, temperature, and fluctuations.
3. Key microwave diagnostic techniques discussed in the document are interferometry, reflectometry, and ECE. Interferometry measures line integrated density, reflectometry measures local density, and ECE measures local electron temperature. These techniques provide important information for understanding issues in plasma physics like stability, waves, and transport.
Optical interferometery to detect sound waves as an analogue for gravitationa...Thomas Actn
This document describes an experiment using a Michelson interferometer to detect sound waves as an analogue for gravitational waves. A tuning fork resonating at 440Hz and a piezoelectric crystal were used to generate sound waves near one arm of the interferometer. An Arduino and oscilloscope measured the resulting interference patterns. The Arduino detected the tuning fork frequency accurately but the oscilloscope only detected around half the frequency due to its limited sampling. Multiple constituent frequencies were detected from hand claps, mimicking bursts from supernovae. While the setup could detect these 'fake' gravitational waves, its low sampling rate limited the detectable frequency window.
Quantum Current in Graphene Nano Scrolls Based Transistortheijes
Graphene based material application as a new centuery material are growing rappidly its carrier transport phenomenon with fast mobility have been focused resently. In the graphene family nanoscrolls because of their especial structure need to be explored. In the presented work a theoretical model for carrier transport in the arcemedus graphene nanoscrolls is reported. Graphene nanoscroll chairal dependent electrical property is considered and then schottky transistor based platform is modeled. The transport coeficient as a fundamental transport factor is discussed. The geometrical paprameter effect on the working phenomenon is considered as well.
Experimental Verification of the Kinematic Equations of Special Relativity an...Daniel Bulhosa Solórzano
The document experimentally verifies the kinematic equations of special relativity and determines the mass and charge of the electron. It describes an experiment that measures the momentum and kinetic energy of electrons over a range of speeds. The data is fitted to both the Newtonian and relativistic kinematic models. The relativistic model provides a much better fit and allows determining the electron charge to mass ratio and mass. The values found agree well with accepted values, supporting the validity of special relativity.
A Novel Space-time Discontinuous Galerkin Method for Solving of One-dimension...TELKOMNIKA JOURNAL
In this paper we propose a high-order space-time discontinuous Galerkin (STDG) method for
solving of one-dimensional electromagnetic wave propagations in homogeneous medium. The STDG
method uses finite element Discontinuous Galerkin discretizations in spatial and temporal domain
simultaneously with high order piecewise Jacobi polynomial as the basis functions. The algebraic
equations are solved using Block Gauss-Seidel iteratively in each time step. The STDG method is
unconditionally stable, so the CFL number can be chosen arbitrarily. Numerical examples show that the
proposed STDG method is of exponentially accuracy in time.
Lecture Notes: EEEC6430310 Electromagnetic Fields And Waves - Transmission LineAIMST University
This document discusses electromagnetic waves and transmission lines. It begins by introducing electromagnetic waves and how they propagate at the speed of light. Transmission lines guide electromagnetic waves from one place to another. The document then discusses transverse electromagnetic waves on transmission lines and how their characteristic impedance is determined. It provides examples of calculating properties of transmission lines like coaxial cable. Overall, the document provides an introduction to transmission lines and how they propagate electromagnetic waves through circuit analysis and wave equations.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
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Monte carlo Technique - An algorithm for Radiotherapy CalculationsSambasivaselli R
Monte Carlo techniques are used to simulate particle transport through complex geometries to calculate dose distributions. The key steps are: (1) sampling the distance to the next interaction, interaction type, and energy/direction of secondary particles, (2) tracking particle histories through condensed histories or splitting/Russian roulette, and (3) calculating dose deposition in voxels. While fully accurate, Monte Carlo is statistically limited by the number of histories. Variance reduction techniques increase efficiency but introduce weighting factors. Overall uncertainty is typically within 3% given proper commissioning and cross-section libraries.
Analysis Of High Resolution FTIR Spectra From Synchrotron Sources Using Evolu...Heather Strinden
This document discusses the analysis of a high resolution FTIR spectrum of trimethylene sulfide (TMS) using evolutionary algorithms (EA). The spectrum was collected at the Canadian Light Source with a resolution of 0.00096 cm-1. Preliminary analysis using traditional methods assigned 2358 transitions. EA was also applied and yielded spectroscopic constants that similarly reproduced the complex experimental spectrum. As a test, EA was also successfully applied to a previously analyzed spectrum of azetidine, demonstrating the robustness of the EA method for automated assignment of dense rovibrational spectra.
- Intermodulated differential immittance spectroscopy (IDIS) is a nonlinear analysis technique that uses two input frequencies (a probe and stimulus signal) to perturb an electrochemical system.
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- Testing on a Schottky diode showed that the differential immittance spectrum could accurately determine the diode's flat band voltage and doping level from a single measurement.
D:\Edit\Super\For Submission 20100306\12622 0 Merged 1267687011Qiang LI
This document discusses a proposed mechanism for electron pairing and superconductivity in ionic crystals. It analyzes a one-dimensional ion lattice chain model and establishes a mechanism for electron pairing driven by lattice vibration modes. The analysis is extended to 3D ionic crystals, focusing on donor-acceptor systems. Electron pairing occurs between energy levels matched to the maximum vibration frequency ωM. Introducing an acceptor band can stabilize electron pairs across the acceptor and full bands, with a binding energy estimated to be at least hωM/(4π).
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The document proposes a rail breakage detector that uses electromagnetics to detect breaks or truncations in railway tracks. Electromagnetic waves would be generated and propagated laterally through the tracks. Any abrupt changes in amplitude, frequency, or wavelength of the waves detected by an oscilloscope in substations along the tracks every 100 km would indicate a break in the tracks between substations. This would allow breaks to be identified and accidents prevented by notifying the nearest station to the break. Implementing such a low-cost system could significantly improve railway safety in India given the number of recent accidents.
Similar to Ultrasonic thickness estimation using multimodal guided lamb waves generated by EMAT (20)
Enhancement in NDT inspection for operational effectiveness, efficiency and e...Innerspec Technologies
We intend to show that any change shall be linked, not only to improvement, but also to immediate cost reduction so that all management structure can conceive quick implementation as
part of its department strategy & enhancement in their budget cost.
For that, concepts such as effectiveness, efficiency and excellence must be approached. We will give clear saving cost ways which will follow the terminology.
In Financial terms and without a deep analysis, we can conrm cost savings above 30% from current prices are achieved.
In last meeting in Davos (Switzerland) in January, the World Economic Forum, expressed its decision to expand investments in green energy. Many new projects are going to be present in the next years.
It is expected a erce competition among companies to be awarded with contracts that will secure their businesses. Some companies have been leading the renewable market for years and they have built a substantial moat which place them in an invaluable position in the market. However, though a good start point, it is not unwavering.
It is time for them to start looking forward and push everyone around to join the industry trend 4.0 also enforced by the Forum. Moving in the right direction will end the controversy of Quality Vs. Production which has dragged down many projects damaging company's image.
Application of conventional NDT methods to supervise the quality has been burdening progress. Production department has been reticent to implement advanced NDT techniques based on wrong concepts.
It is time for NDT companies to look at the industry in the right way, showing that there is a way to work for all. Just by moving forward.
In the next lines, we will try to show and explain that NDT industry must lead the progress introducing FEA analysis in their reports if they want to join all stakeholders around project success.
The document describes the development of an improved ultrasonic testing system called the Rollmate G3 for inspecting mill rolls. The new system was designed to address limitations of previous eddy current inspection methods and to reliably detect all types of surface and subsurface defects in rolls. It incorporates 20 ultrasonic inspection channels covering multiple orientations to optimize detection of defects regardless of orientation. Extensive testing on rolls with natural and artificial defects demonstrated it can find flaws that previous methods missed. The new Rollmate G3 system is aimed to provide comprehensive roll inspection for mills without compromises on capability.
Sistema de inspección híbrido EMAT-Visión para optimar el proceso de fabricac...Innerspec Technologies
Uno de los principales retos a los que se enfrenta la industria del automóvil es la reducción del peso de partes estructurales, sin que esto afecte a la seguridad del producto final. La fabricación de Tailor Welded Blanks (TWB) en la industria del automóvil es un proceso avanzado que consiste en combinar varias chapas finas de metal que son soldadas mediante tecnología láser antes del proceso de estampado. Aunque la inspección de TWB suele llevarse a cabo mediante la tecnología EMAT, ésta presenta ciertas limitaciones a la hora de identificar defectos superficiales tales como el desalineamiento lateral y vertical de una chapa respecto a otra. Con el fin de
afrontar esta limitación, los fabricantes inspeccionan las chapas con un equipo adicional de visión artificial que complementa los resultados del equipo EMAT. Este artículo presenta el nuevo sistema de inspección OPTIBLANKS, que es el primer equipo híbrido que combina EMAT y visión artificial para establecer un criterio de aceptación/rechazo unificado a través de la combinación de la información proporcionada por ambas tecnologías no destructivas. Esta hibridación dota al sistema final de más inteligencia, lo que le permite tomar decisiones más robustas y optimizar el proceso de fabricación y la calidad del producto final. El artículo presenta los resultados del proceso de validación de OPTIBLANKS en una planta de fabricación de TWB (Gestamp Solblank). Los resultados muestran la necesidad de combinar la información de las dos técnicas para incrementar la probabilidad de detección (POD) del sistema de inspección.
Detección de delaminaciones y otros defectos de unión en productos de acero m...Innerspec Technologies
Ondas guiadas superficiales (Rayleigh) y tipo Lamb fueron usadas para la detección de delaminaciones, residuos de acero embebidos en la matriz del material y problemas de adherencia de la frágil capa intermetálica de Al-Fe en la interfaz formada por el aluminio revestido y el acero generados durante el
proceso de laminación en frío “Cold Roll Bonding” (CRB). Se fabricaron muestras multicapa con defectos artificiales de distintos tamaños, localizados entre el aluminio recubierto y el acero. El objetivo de este manuscrito es mostrar la sensibilidad de las ondas guiadas EMAT para indicar cualitativamente
la presencia de defectos, utilizando para ello técnicas de atenuación de la señal adquirida. Para la generación y recepción de las ondas guiadas se usaron transductores acústico-electromagnéticos (EMAT) dispuestos en configuración pitch-catch (transmisión-recepción). La toma de medidas se llevó a cabo en el material laminado antes y después de aplicar el recocido, de forma que se pudieran evaluar las diferencias que el tratamiento térmico provocaba en términos de atenuación y de relación señal-ruido (SNR). El modo S0 de onda Lamb se demostró adecuado para la detección de delaminaciones y residuos de acero embebidos en la matriz
del material, existiendo una relación entre el grado
de atenuación y, el tipo y tamaño de defecto, así
como con la realización del recocido. Sin embargo
dicho modo no pudo detectar falta de adherencia
de la frágil capa intermetálica de Al-Fe debido a los
espesores de la capa de aluminio recubierto y del
acero. Secciones de las muestras inspeccionadas
con EMAT fueron posteriormente evaluadas metalográficamente para corroborar las indicaciones de
defecto. Los resultados demostraron la viabilidad del uso de ondas guiadas Rayleigh y Lamb para la detección de defectos de unión en la producción en serie de planchas bimetálicas de Al-Sn/Acero.
Nondestructive Testing (NDT) has evolved from being a “necessary evil” to being an essential source of competitive advantage. The right technique not only helps control the quality of the final product, but also provides valuable process control feedback to improve productivity, reduce cost, and increase the
efficiency of the welder. This is especially important in high-volume, continuous processing lines where a few minutes of bad production can result in significant losses.
In the last decade, powerful Ultrasonic EMAT technology has come of age with tremendous success, becoming the technique of choice for many applications.
Final strip and sheet steel product is commonly inspected with great scrutiny to qualify material for high-end product requirements. Surface flaws such as slivers, cracks, laps, etc., disqualify these materials from being used in automotive and big box applications. Internal defects such as voids, cracks, laminations, porosity and segregation may remain undetectable with surface inspection methods as they have not yet manifested at the surface. These internal defects often propagate to the surface where ultimately they are detectable in the finished product stage in the form of slivers, blisters, etc., although remaining undetectable in the steel making, hot-rolling, pickling, cold rolling and subsequent finishing operations. Surface flaws are a key cause of down grading of finished product and a significant cost to the steel maker as all value added operations are complete before detection and down grading are possible.
In today’s competitive environment, it is key to maximize utilization of mill assets and to avoid adding value to material which can be known early in the manufacturing process to contain deleterious defects. Using proven methods of volumetric material inspection in two separate case studies, methods have been developed to allow the steel maker to identify poor material early in the process thus avoiding the value added processes on these materials and only processing materials which with a probability of final inspection passage.
The United States consumes an incredible amount of energy every day, and this demand for energy shows no signs of decreasing. The U.S. pipeline infrastructure is critical to supporting this growing demand. We take a look at this infrastructure and break down some of the facts including age, material, miles and production.
To learn more about energy production in the U.S. visit the U.S. Energy Information Administration or contact one of our oil & gas sales engineers.
1) The document discusses the differences between long range ultrasonic testing (LRUT) and medium range ultrasonic testing (MRUT) for inspecting pipelines. LRUT uses lower frequencies to inspect over longer distances, while MRUT uses higher frequencies to inspect shorter distances but with higher sensitivity.
2) It describes a new technique using MRUT with shear horizontal guided waves for circumferential scanning to inspect inaccessible areas like under pipe supports. This provides better detection and resolution than LRUT within close proximity to defects.
3) The new technique uses a magnetostrictive strip adhered around the pipe that is scanned by a single transducer scanner to perform circumferential inspections and complement LRUT for inspecting shorter
The field of Non Destructive Testing (NDT) has shown tremendous growth in the last half century. Its ability to provide safe volumetric inspection of materials with limited access areas makes ultrasonic testing (UT) one of the fastest growing technique in NDT.
However, the Achilles heel of Ultrasonic Testing (UT) has always been the transferring of energy from the UT probe into the material subject of the inspection. Because air limits the transfer of ultrasound, the transducers need to be coupled to the material using a liquid that promotes the transfer of energy into the material.
Austenitic welds are extensively used in nuclear, petrochemical and process industries. Due to the strong material anisotropy and coarse grain size in the dendritic weld zone, they are difficult to inspect with ultrasound. In this regard, the shear horizontal (SH) wave mode is far superior to the more conventional shear vertical (SV) and longitudinal wave modes. In this paper, an electromagnetic acoustic transducer (EMAT) is designed and used for the inspection of two austenitic weld samples. Despite the low efficiency of EMAT generation due to low conductivity of austenitic stainless steel material and strong attenuation in the weld zone, good signal to noise ratio is achieved with optimized EMAT probes and state-of-the-art instrumentation. The angle beam EMAT probe successfully detected all defects in the samples with good signal to noise ratio including a 2% defect.
The capability of detection a defect across a 2’’ inch thick and 2’’ wide austenitic weld zone is also demonstrated in the paper.
Electric Resistance Weld (ERW) tubes and pipes are extensively used un many applications including Oil Country Tubular Goods (OCTG) and high quality structures. Efficient in-line nondestructive testing techniques are needed to ensure that the weld quality meets applications standards.
In the fall of 2002, a revolutionary method by which to inspect mill rolls was introduced to the metal producing industry. This ultrasonic approach was designed to overcome the inadequacies of existing inspection techniques while
maximising return on investment. Since then, a number of improvements have been made, and with input from many
roll shops, the latest technologies provide the most comprehensive tool available for the inspection of all types of mill rolls. This paper provides an overview of mill roll
inspection technology and the effects that various inspection technologies can have on the efficiency and costs associated with operating a roll shop. It will also highlight how new techniques provide alternatives otherwise not available.
Clad metals are composite metal containing two or more layers that have been bonded together. The bonding may have been accomplished by rolling, extrusion, welding, diffusion bonding, casting, heavy chemical deposition, or heavy electroplating. Clad metals offer the opportunity to combine desirable properties and/or characteristics of individual metals and alloys into a material "system" that provides improved characteristics over the individual metals. In the event the bond quality is compromised, these materials will not meet their original purpose. Disbond in clad layers is very similar to an internal void in single layer materials such as steel strip material.
This document discusses a study on using guided wave electromagnetic acoustic transducer (EMAT) techniques to inspect three-layered clad coin stock materials for delamination. The study involved:
1. Developing guided wave dispersion curves for the intact three-layer structure and for delaminated substructures.
2. Modeling guided wave propagation and interaction with laminations using finite element analysis.
3. Testing an EMAT inspection system installed on a coin stock production line, which successfully detected disbonds.
4. Verifying the guided wave modeling through destructive and offline nondestructive testing techniques.
Ultrasonic guided wave techniques have great potential for structural health monitoring applications. Appropriate mode and frequency selection is the basis for achieving optimised damage monitoring performance.
In this paper, several important guided wave mode attributes are
introduced in addition to the commonly used phase velocity and group velocity dispersion curves while using the general corrosion problem as an example. We first derive a simple and generic wave excitability function based on the theory of normal mode expansion and the reciprocity theorem. A sensitivity dispersion curve is formulated based on the group velocity dispersion curve. Both excitability and sensitivity dispersion curves are verified with finite element simulations. Finally, a
goodness dispersion curve concept is introduced to evaluate the tradeoffs between multiple mode selection objectives based on the wave velocity, excitability and sensitivity.
While research and development of Electro-Magnetic Acoustic Transducer (EMAT) technology has been active for several decades, hardened production inspection system applications remain limited. Applications remain limited despite the several and distinct advantages and EMAT probe can have over conventional piezoelectric ultrasonic devices.
In addition to being comparable in ultrasonic wave mode generation and sensitivity, under proper design, an EMAT probe offers the following advantages for the production minded engineer: (1) no fluid couplant is required, (2) the test can be non-contact, (3) works on rough, dirty, and hot surfaces, (4) can be operated at very high scan rates, (5) easy to automate, and (6) capable of generating useful waves modes that are difficult to generate with piezoelectric devices. Basic elements of an EMAT system are explained and a comparison to conventional piezoelectric devices is made. By using real application cases, the benefits of EMATs are demonstrated. These real cases include: (1) flash butt-weld inspection, (2) mill roll inspection, (3) automotive laser weld inspection, and (4) tube & pipe inspection.
This document discusses electromagnetic acoustic transducer (EMAT) technology. It provides an overview of how EMATs work by inducing ultrasonic waves into a test object using magnetic fields rather than requiring direct contact or coupling medium like piezoelectric transducers. The document outlines the key advantages of EMATs such as being able to perform dry inspections on hot parts or through coatings. It also summarizes the different wave modes EMATs can generate including shear waves and guided waves. Finally, it provides examples of commercial applications of EMATs that are growing as the technology advances.
Austenitic welds are widely used in nuclear, petrochemical and process industries. The strong material anisotropy and coarse grain structure in the dendritic weld zone makes these welds very difficult to inspect with conventional techniques. It is well-known that the shear horizontal (SH) wave is well-suited for this inspection and that electromagnetic acoustic transducer (EMAT) is the best technique for generating this wave mode, but the lack of equipment has precluded its application in the field. This paper presents the development of one channel and phased array EMAT systems and results from tests conducted on samples provided by the Electric Power Research Institute (EPRI). The results show the potential of this new equipment
for austenitic weld inspection, which opens up new possibilities for research and field use.
Camera Encoded Phased Array for Semi-Automated Inspection of Complex Composit...Innerspec Technologies
This paper introduces a new wireless solution that permits performing accurate and traceable ultrasonic scans of components with complex geometries using a hand-held scanner. The system integrates an array of 3D cameras that track the position of the hand of the inspector with a high-performance PAUT instrument to provide accurate, highresolution C-Scans on any component. This paper provides results of hand-held scans on complex composite parts,
and explores how the solution compares with traditional semi-automatic and automatic systems in terms of setup, ease-of-use, performance, productivity, and cost.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
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Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Ultrasonic thickness estimation using multimodal guided lamb waves generated by EMAT
1. Ultrasonic Thickness Estimation using Multimodal Guided Lamb Waves
generated by EMAT
Joaquín García-Gómez1
, Roberto Gil-Pita1
, Antonio Romero-Camacho2
, Jesús Antonio Jiménez-Garrido2
,
Víctor García-Benavides2
, César Clares-Crespo1
, Miguel Aguilar-Ortega1
1
Signal Theory and Communications Department
University of Alcala
Alcala de Henares, Madrid, Spain
(34) 91-8856751; fax (34) 91-8856699; email roberto.gil@uah.es
2
Innerspec Technologies Europe S.L
Torres de la Alameda, Madrid, Spain
ABSTRACT
The objective of this paper is to study how the selection of the coil and the frequency affects the received modes in
guided Lamb waves, with the objective of analyzing the best configuration for determining the depth of a given
defect in a metallic pipe with the minimum error. Studies of the size of the damages with all the extracted
parameters are then used to propose estimators of the residual thickness, considering amplitude and phase
information in one or several modes. Results demonstrate the suitability of the proposal, improving the estimation of
the residual thickness when two simultaneous modes are used, as well as the range of possibilities that the coil and
frequency selection offers.
Keywords: EMAT sensors, Lamb waves, pipeline inspection, defect sizing, coil selection, frequency selection
INTRODUCTION
Defect sizing in pipeline inspection allows companies to determine when a pipe must be replaced, avoiding costly
repairs in their assets. To tackle this issue, Lamb ultrasonic waves generated through Electro-Magnetic Acoustic
Transducers (EMAT) allow thickness estimation without direct contact with the surface of the metallic material
under investigation [1]. The use of this technology with a meander-line-coil allows generating waves in a directional
way [2], which facilitates differentiating between circumferential and axial scans in Non-Destructive Testing (NDT)
for pipeline inspection [3].
However, the shape of the defect changes the behavior of the ultrasonic signals when they pass through the pipeline,
and it is not easy to predict the amplitude and phase of the wave in function of the residual thickness [4,5]. In recent
studies the use of machine learning techniques applied to information extracted from signals sensed at different
frequencies has been demonstrated to improve the accuracy of the estimation, but the use of multiple frequencies in
general requires more complex sensing devices and more time. A possible way to address these disadvantages is the
use of different modes sensed at a unique frequency, but in this case the selection of the coil and the inspection
frequency becomes a critical aspect, since these different modes must be separable in the measurement, and this is
not always the case.
This paper presents a theoretical study in which the selection of the coil and the frequency for multimodal thickness
estimation are analyzed. The objective is to determine the relationship between the performance of the estimator and
the configuration of the sensing system. The problem was approached from two perspectives. First, a signal
processing based theoretical framework is proposed. Second, simulations obtained by a Finite Element software are
considered. Results demonstrate the suitability of the proposals, improving the estimation of the residual thickness.
2. LAMB WAVE GENERATION USING EMAT SENSORS
In this section the generation of Lamb waves through EMAT sensors will be described. These sensors are composed
of a magnet and a coil wire. The current is induced in the surface of the ferromagnetic material when the alternating
electrical current flow through the coil wire is placed in a uniform magnetic field near the material. When this field
interacts with the field generated by the magnet, Lorentz force appears. Because of that, a disturbance affects to the
material, creating an elastic wave. If the vibration is coplanar with the propagation plane, these waves are called
Lamb waves. Conversely, the interaction of Lamb waves with a magnetic field induces current in the EMAT
receiver coil circuit.
Lamb waves are characterized by their dispersion and sensitivity to thickness variations. Besides, they can be
divided into modes: symmetric and asymmetric modes. Each mode is composed of two waves (longitudinal and
transversal). They travel at different angles 𝜃" and 𝜃# with velocities 𝑐" and 𝑐#, where the latter refer to the sound
velocity in longitudinal and transversal components, respectively. Considering a Lamb mode that moves in the 𝑥
direction at velocity 𝑐' with a frequency 𝑓, then the wavenumber 𝑘 is related to the longitudinal and transversal
components of the wave:
𝑘" cos 𝜃" = 𝑘# cos 𝜃# = 𝑘 =
2𝜋𝑓
𝑐'
(Eq. 1)
where 𝑘" = 2𝜋𝑓 𝑐" and 𝑘# = 2𝜋𝑓 𝑐# , are the wavenumber of the longitudinal and transversal components,
respectively. Furthermore, the displacement of each wave in the 𝑧 axis can be obtained using 𝛼" and 𝛼#, so that:
𝛼" = 𝑘" sin 𝜃" = 2𝜋𝑓
1
𝑐"
: −
1
𝑐'
:
(Eq. 2)
𝛼# = 𝑘# sin 𝜃# = 2𝜋𝑓
1
𝑐#
: −
1
𝑐'
:
(Eq. 3)
Considering that the wave is reflected in the surfaces and applying the boundary conditions, we can get an equation
related to the dispersion of the Lamb modes. Equation (4) refers to the symmetric modes and equation (5) refers to
asymmetric ones.
4𝑘:
𝛼" 𝛼# sin
𝛼"ℎ
2
cos
𝛼#ℎ
2
+ sin
𝛼#ℎ
2
cos
𝛼"ℎ
2
𝛼#
:
− 𝑘: :
= 0 (Eq. 4)
4𝑘:
𝛼" 𝛼# cos
𝛼"ℎ
2
sin
𝛼#ℎ
2
+ cos
𝛼#ℎ
2
sin
𝛼"ℎ
2
𝛼#
:
− 𝑘: :
= 0 (Eq. 5)
From the previous equations, it can be derived that there exists a relation between the excited frequency 𝑓, the
thickness of the pipe ℎ and the phase velocity 𝑐'. In particular, each mode travels at different 𝑐' depending on the
other above-mentioned parameters. We get a similar relation with the group velocity 𝑐B, defined in equation (6).
𝑐B = 𝑐'
:
𝑐' − 𝑓ℎ
𝜕𝑐'
𝜕𝑓ℎ
DE
(Eq. 6)
Solving the previous equations for different values of frequency and thickness we obtain the phase and group
velocity for each propagating mode.
3. Now we will consider how signals are generated and received in the pipeline. The EMAT system consists of a
meander-line-coil which generates two signals per loop in the system (one per meander). These waves are
characterized by their wavelength which depends on the separation of the meanders. The following equations are
valid for one mode and then we will iterate for all the modes which appear at a given frequency. Thus, we have to
set the wave equation depending on the group and phase velocities. Considering 𝑓 as the excited frequency, the
transmitted signal propagating in the 𝑥 axis will be generated according to equation (7).
𝑠 𝑥, 𝑡 = sin 2𝜋𝑓 𝑡 −
𝑥
𝑐'
(Eq. 7)
Please note here that the velocity 𝑐' will depend on the frequency and the thickness of the pipe. In a real case, the
transmitted signal includes an envelope 𝑤(𝑡) that generates the transmitted wave packet 𝑝 𝑥, 𝑡 . This envelope
limits the transmission time, and allows controlling the length of the transmitted pulse. Typically, the length of this
envelope is described in function of 𝐶, the number of cycles included in the wave packet. This envelope will travel
at an average velocity of 𝑐B, and in general its shape will change with the distance due to dispersion effects. So, once
the envelope is considered, the transmitted wave packet 𝑝 𝑥, 𝑡 will be expressed using equation (8).
𝑝 𝑥, 𝑡 = sin 2𝜋𝑓 𝑡 −
𝑥
𝑐'
𝑤 𝑡 −
𝑥
𝑐B
(Eq. 8)
From this point, instead of using the transmitted envelope 𝑤(𝑡) we will use using 𝑤(𝑡), which changes its shape in
function of the distance due to dispersion effects. It is also necessary to consider that under EMAT technology the
excitation signal is generated in a set of 𝑁 loops of a coil, separated by a distance 𝐿, which will generate the
propagation wave 𝑦 𝑥, 𝑡 using equation (9).
𝑦 𝑥, 𝑡 = −1 R
sin 2𝜋𝑓 𝑡 −
𝑥 + 𝑚
𝐿
2
𝑐'
𝑤 𝑡 −
𝑥 + 𝑚
𝐿
2
𝑐B
:T
RUE
(Eq. 9)
Each loop generates two signals (one per meander), and the sign of their contribution to the propagation wave
𝑦 𝑥, 𝑡 is included in the term −1 R
. Besides, the measure is sensed at a distance 𝐷, in another set of 𝑁 loops
separated by a distance 𝐿. So, the received signal 𝑧 𝑡 will be expressed using equation (10).
𝑧 𝑡 = −1 RXY
sin 2𝜋𝑓 𝑡 −
𝑥 + 𝑚 + 𝑛
𝐿
2
𝑐'
𝑤 𝑡 −
𝑥 + 𝑚 + 𝑛
𝐿
2
𝑐B
:T
RUE
:T
YUE
(Eq. 10)
The signal received from each mode 𝑧 𝑡 has different values of 𝑐' and 𝑐B, as it was concluded from equations (4),
(5) and (6). Thus, each mode arrives at the receiver with different amplitude and envelope, depending on the
attenuation of each mode and the difference of phase when the signal is received in the coil. Therefore, the amount
of energy of the received signal will vary in function of the frequency.
In order to find out more about the behavior of the modes, a frequency sweep has been carried out between 0 and
800 kHz with one coil and 𝐶 = 4 cycles per wave packet. Figure 1 shows the phase velocity (left) and group
velocity (right), where black color means the energy is maximum at that frequency. Dispersion has been taken into
account to carry out these experiments, since the signal 𝑝 𝑥, 𝑡 has been decomposed with the envelope window
4. 𝑤 𝑡 through the Fourier Transform, and different velocity has been applied to each frequency component. These
graphs correspond to a steel pipe with the following parameters: Young’s modulus 𝐸 = 210 ∙ 10]
𝑁 𝑚:
, Poisson’s
ratio 𝜈 = 0.3 and density 𝜌 = 7800 𝑘𝑔 𝑚a
.
(a) (b)
(c) (d)
(e) (f)
Figure 1: Phase velocity (a) and group velocity (b) in function of the product frequency by thickness, using
coils with different 𝑳 value.
5. The coil used in the experiments has the following parameters: distance between loops 𝐿 ranging from 0.3 to 0.5
inches, and 𝑁 = 3 loops. It can be observed that the same coil could be used to excite other frequencies, even if it
has been designed to get the maximum energy in a given frequency. Furthermore, if we want to analyze the behavior
of the modes in a deep way, we could change the length L of the coil. In Figure 1 it is observed that the points and
areas of maximum energy vary significantly from one coil to another.
FREQUENCY AND COIL SELECTION FOR MULTIMODAL FEATURE
EXTRACTION
The modeling of the pipeline by means of the ultrasound waves is a non-trivial problem. The changing shape of the
defects makes difficult to draw general conclusions about the relation between the defect and the received signals.
The distortion caused by the defects over the different modes strongly varies with the shape of the mode [4,5]. For
instance, the amplitude of the signal, the time of arrival (group velocity 𝑐B) and the phase velocity 𝑐' of the wrap-
around signal vary with the dimension and shape of the defect.
Thus, it is necessary to analyze how the different modes are going to be represented in the received signal, in order
to look for the best configuration (frequency and size of the coil) that allows a better representation of the different
modes over the same signal.
As it was stated, a meander-line-coil is used to generate the ultrasonic signals that are analyzed once they wrap the
pipeline. It allows us to know the condition of the pipes depending on the different modes and wrap arounds
received. In order to investigate how the behavior of the modes changes according to the length of the coil, a sweep
of experiments has been carried out with coils from 0.30 inches to 0.55 inches, in steps of 0.01 inches. The most
relevant results are shown in Figure 2, where we show where the energy of the different modes is located in a time-
frequency representation. Both asymmetric (A0, A1, A2, A3) and symmetric (S0, S1, S2, S3) modes are plot in
different colors. In each of the modes, curves indicate the area where the energy of the mode is higher or lower.
Results from this figure show that as we change the length of the coil, the parameters related to the modes
(frequency of appearance, area of maximum energy, etc.) are not the same. The final effect is that the modes “move”
in frequency and time. For instance, as the length of the coil in higher, some of the modes appear at lower
frequencies. That is the case of A0, S0, A1 and S1 modes. Other modes disappear from the observed window, such
as the A2 mode (pink), whose second wrap around went away from 0.40 inches to 0.45 inches. First wrap around
disappear from 0.45 inches to 0.50 inches.
7. However, the usefulness of these graphs is that we can set a frequency depending on the modes or wrap arounds we
are interested in, particularly when the objective is not to use just one mode. For instance, if we want to focus on
modes A1 and S1 (dark blue and yellow), it can be seen that 0.30 and 0.35 inches are not the suitable lengths
because both modes will appear mixed in the received signal. We should choose a higher value, such as 0.45 inches,
where first wrap-around of A1 mode as well as first and second wrap around from S1 mode are well separated in
time between 400 and 600 kHz approximately, so they will not be overlapped. Other option would be to choose a
value of 0.50 inches, where these modes are almost completely separated, but including the second wrap-around of
both modes or even the third one from the S1 mode. Again, it is clear that 0.55 inches is not a suitable value because
these modes start to appear together again.
SMART SOUND PROCESSING FOR SIZING ESTIMATION
If we want to solve the problem of pipeline sizing, it is necessary to apply a pattern recognition system, which is
composed of two stages. In the first stage, useful information is extracted from the signals in the form of features.
Later, in a second stage, a predictor tries to learn a model which will be useful for predicting the defects presented in
the pipeline.
To extract useful information from the received signal is very important in the process, since it will be the “raw
material” that the predictor will use. Analyzing a set of signals from real pipelines and the state of the art [6], we
observe that the following features could be useful for the problem at hand:
• Average echo energy (dB), which represents the average energy of the echo received.
• Peak wrap-around energy (dB), which represents the maximum energy of the pulse. We have considered
±30 µs around 𝑡d, the maximum of the signal in the case of absence of defect, to look for the maximum of
each signal.
• Average wrap-around energy (dB), which represents the average energy of the pulse. We have considered
±30 µs around 𝑡d, the maximum of the signal in the case of absence of defect.
• Wrap-around phase delay (µs), which represents how much time has passed between the pulse was sent and
it was received in the same point of the pipeline. It is determined measuring the time difference between
𝑡d and its closest maximum in 𝑧(𝑡). Please note that a delay larger than 1 2𝑓 causes uncertainty, which
conditions the usefulness of this measurement.
• Wrap-around group delay (µs), denoted 𝑡B. In order to estimate this measurement, we consider the centroid
of the average energy of the pulse around 𝑡d, with equation (11).
𝑡B =
𝑡 𝑧(𝑡):efXa∙Edgh
eUefDa∙Edgh
𝑧(𝑡):efXa∙Edgh
eUefDa∙Edgh
(Eq. 11)
Figure 3: Model of the simulated defects.
l
s
d
h
8. Once we have obtained the features, we need to apply a nonlinear predictor to get the final profile of the pipeline
and to know the performance of the developed model. Neural Networks have been applied, specifically the Multi
Layer Perceptron (MLP) [7]. In this paper MLPs with a hidden layer of twenty neurons have been trained using the
Levenberg-Marquardt algorithm [8].
From the results presented in Figure 2, we will select and 𝑓 = 450 and a coil with 𝐿 = 0.52 inches. So, in the case
of using just the main mode we will consider 5 features, and in the case of considering two modes we will have 9
features (4 wrap-around features for each mode plus the echo energy).
To study the relationship between these parameters and the shape of the defects, we have used the Finite Element
Method (FEM) included in the Partial Differential Equations Toolbox of Matlab. With these simulations we have
generated a database with several different defects. The defects have been characterized with three parameters:
length (𝑙), depth (𝑑) and slope (𝑠). Figure 3 describes the meaning of these parameters in a real pipeline. The
thickness of the pipe used is ℎ = 7.8 mm, and the distance to the receiver is 𝐷 = 0.7 m. For simplicity, we have not
modeled the width of the defect, that is to say, we have not considered the 𝑦 dimension of the pipeline.
Table 1: RMSE (mm) in the estimation of the residual thickness using an MLP with 20 neurons in the hidden
layer for different number of used modes.
S1 mode
5 features
S1 and A1 modes
9 features
RMSE (mm) 10.50 mm 9.72 mm
In a second approach, we have developed an experiment using a synthetic database for estimating the residual
thickness of the pipeline. The database consists of 384 signals generated with defects of different shape. The length
of the defect (𝑙) ranged from 10 to 100 mm, the depth (𝑑) from 0 to 9 mm, and the slope (𝑠) from 1 to 100 mm.
To obtain the prediction results, 𝑘-fold cross validation was applied in the generated database, being 𝑘 = 5. This
method consists in dividing the database in 𝑘 groups so that the full process is repeated 𝑘 times, using one group of
signals as test subset and the remaining 𝑘 − 1 groups as training subset. Results are then averaged to obtain the Root
Mean Square Error (RMSE) of the estimation of the depth. The advantage of this method is that the obtained results
are generalizable to defects different from those used in the database.
The objective is to know how well estimated is the received signal at different frequencies, so different experiments
have been considered. First, we have considered the use of only one frequency, and we have also studied what
happens when both frequencies are used at the same time. Concerning the features, the usefulness of each feature
has been studied, and the inclusion of all three features has also been considered. Table 1 shows the RMSE in
function of the features and the frequencies. In all the cases above it is clear that as we get better results when two
modes are used.
CONCLUSIONS
Pipeline inspection problem can be approached in many different ways. Lamb wave generation through EMAT
sensors proves to be a very effective and useful one. However, the amount of information provided by the wrap-
around signals needs to be processed by advanced techniques, such as smart sound processing algorithms. Thanks to
them, it is feasible to get good estimation results of the pipeline defects, in both real and simulated signals.
9. In this paper we establish tools for determining the frequency and dimensions of the coil in order to be able to
analyze two modes with an unique scan. We study how the behavior of the modes change when the length of the
used coil is different, demonstrating its interest for multimodal approaches. Studies of the size of the damages with
all the extracted parameters have been used to propose estimators of the residual thickness, considering amplitude
and phase information. Results with two modes demonstrate the suitability of the proposal, improving the estimation
of the residual thickness.
ACKNOWLEDGEMENTS
This work has been funded by Innerspec Technologies Europe S.L through the “Chair of modeling and processing
of ultrasonic signals” (CATEDRA2007-001), and by the Spanish Ministry of Economy and Competitiveness-
FEDER under Project TEC2015- 67387-C4-4-R.
CONFLICTS OF INTEREST
The authors declare that there is no conflict of interest
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