Measurement Of Phase Shift Research Articles

Measurement of Water Holdup in Oil–Gas–Water Slug Flow Using Microstrip Antenna

Water holdup measurement in multiphase flow with varying water salinity is a significant and challenging research topic. In this study, a new microstrip-antenna-based microwave transmission sensor (MAMTS) and a new decoupling method are proposed to achieve salinity independent measurement of water holdup in oil-gas-water slug flows. The MAMTS is formed by two identical microstrip antennas whose configurations are optimized and determined by the formula computation and the finite element method. Owing to the optimum design of the antenna configuration and the determination of the suitable working frequency, the amplitude attenuation and phase shift simultaneously measured by the MAMTS are both sensitive to the water holdup and water conductivity. To overcome the existing problem that the salinity affects the water holdup measurement only using amplitude attenuation or phase shift, a new decoupling method based on the simultaneous measurement of amplitude attenuation and phase shift is proposed. The measurement characteristics of the MAMTS to different flow structures with different water holdups and the influence of the water conductivity change are studied by the static experiments. Finally, the performance of the MAMTS and the decoupling method are evaluated in the experiment of oil-gas-water slug flows. The experiment results indicate that the amplitude attenuation and phase shift both can effectively sense the information of water holdup and water conductivity. However, they present different measurement characteristics to different flow structures. By taking the flow structures into consideration and using the new decoupling method, the water conductivity can be derived online and salinity independent water holdup measurement in oil-gas-water slug flow can be achieved.

Two-step phase shifting profilometry based on Lissajous ellipse fitting technique

<sec> Phase shifting profilometry (PSP) is an effective technique to reconstruct the three-dimensional shape of object. In general, PSP needs three or more fringe patterns with phase-shifting accurately known to extract the phase distribution of objects. Therefore, the scene and the test objects should remain stationary during capturing the fringe patterns. However, the phase shifts may be unknown in an actual PSP measurement system, especially when measuring the moving object, that is, the phase-shift error may be introduced during the obtaining of the phase-shifting fringe patterns of moving object. In the dynamic measurement scenario, the use of fewer fringe patterns can realize the faster measurement speed and suppress the phase shift error introduced by the moving object. In this paper, a two-step PSP algorithm is proposed based on Lissajous ellipse fitting (LEF). The proposed method uses only two fringe patterns to extract the phase distribution of the object and can suppress the phase shift error caused by the moving object. </sec><sec> However, in a practical PSP system, the spatiotemporally varying background intensity and modulation also significantly affect the phase accuracy extracted by LEF, and thus three error-suppressing methods are proposed to reduce the phase error caused by the non-uniform background intensity and modulation. In order to verify the effectiveness of the three error-suppressing methods, we analyze and compare their performances of error suppression under different background intensities and modulations. The advantages of three error-suppressing methods can be summarized as follows. 1) The mean and modulation correction technique has greater advantage than the other two when the background intensity and modulation vary with time. 2) When the background intensity and modulation are relevant to pixel position and the number of fringe patterns, the empirical mode decomposition normalization can more effectively suppress the influence of the non-uniform background intensity and modulation. </sec><sec> In experiment, a two-step phase-shifting dynamic measurement based on LEF is conducted. Compared with the traditional PSP which needs at least three fringe patterns, the two-step PSP algorithm successfully extracts the phase with only two fringe patterns and suppresses the phase shift error caused by the motion of the object. Compared with Fourier transform profilometry (FTP), the two-step PSP algorithm can obtain very accurate phase distribution and retain many phase details. </sec>

Diagnosis of multilayer structures and composite parts by multifrequency phase detection

The article considers the issue of diagnosing the condition of multilayer elements and structures. Probing methods are considered. A multiphase detection method has been proposed to generate diagnostic information that allows the reflected signals from several consecutive layers to be obtained. The reflection distance is determined for each layer. The presentation of a two-dimensional model of structural sounding in the presence of two objects of study was considered. The three-dimensional model of search of objects of research of concrete designs considered in work provides probing by spherical waves of a detail, measurement of phase shifts of signals reflected from internal objects of research in three points. Division by means of one of mathematical models of signals are reflections from each object of research and determination of coordinates of objects of research and can by means of the mathematical model was represent. The equipment of a measuring instrument was developed to study the analytical multifrequency phase method of distance measurement. This system can be used to diagnose defects in multilayer structures that can transmit radio waves. Also it can be used for quality control of the put coverings and for the analysis of thickness of composite materials, isolation layers in the equipment.

Fano-Kondo resonance versus Kondo plateau in an Aharonov-Bohm ring with an embedded quantum dot

We theoretically examine the transport through an Aharonov-Bohm ring with an embedded quantum dot (QD), the so-called QD interferometer, to address two controversial issues regarding the shape of the Coulomb peaks and measurement of the transmission phase shift through a QD. We extend a previous model [B. R. Bulka and P. Stefanski, Phys. Rev. Lett. 86, 5128 (2001); W. Hofstetter, J. Konig, and H. Schoeller, ibid. 87, 156803 (2001)] to consider multiple conduction channels in two external leads, L and R. We introduce a parameter p_{\alpha} (|p_{\alpha}| \le 1) to characterize a connection between the two arms of the ring through lead \alpha (=L, R), which is the overlap integral between the conduction modes coupled to the two arms. First, we study the shape of a conductance peak as a function of energy level in the QD, in the absence of electron-electron interaction U. We show an asymmetric Fano resonance for |p_{L,R}| = 1 in the case of single conduction channel in the leads and an almost symmetric Breit-Wigner resonance for |p_{L,R}| < 0.5 in the case of multiple channels. Second, the Kondo effect is taken into account by the Bethe ansatz exact solution in the presence of U. We precisely evaluate the conductance at temperature T=0 and show a crossover from an asymmetric Fano-Kondo resonance to the Kondo plateau with changing p_{L,R}. Our model is also applicable to the multi-terminal geometry of the QD interferometer. We discuss the measurement of the transmission phase shift through the QD in a three-terminal geometry by a "double-slit experiment." We derive an analytical expression for the relation between the measured value and the intrinsic value of the phase shift.

The phase of the BAO on observable scales

The baryon acoustic oscillations (BAO) provide an important bridge between the early universe and the expansion history at late times. While the BAO has primarily been used as a standard ruler, it also encodes recombination era physics, as demonstrated by a recent measurement of the neutrino-induced phase shift in the BAO feature. In principle, these measurements offer a novel window into physics at the time of baryon decoupling. However, our analytic understanding of the BAO feature is limited, particularly for the range of Fourier modes measured in surveys. As a result, it is unclear what the BAO phase teaches us about the early universe beyond what is already known from the cosmic microwave background (CMB). In this paper, we provide a more complete (semi-)analytic treatment of the BAO on observationally relevant scales. In particular, we compute corrections to the frequency and phase of the BAO feature that arise from higher order effects which occur in the tight coupling regime and during baryon decoupling. The total phase shift we find is comparable to a few percent shift in the BAO scale (frequency) and thus relevant in current data. Our results include an improved analytic calculation of the neutrino induced phase shift template that is in close agreement with the numerically determined template used in measurements of the CMB and BAO.

Experimental entanglement-assisted weak measurement of phase shift.

Weak value amplification is a popular method in quantum metrology for enhancing the sensitivity at the expense of the signal intensity. Recently, it was suggested that the trade-off between signal intensity and sensitivity can be improved by using an entangled auxiliary system. Here, we experimentally investigate such entanglement-assisted weak measurement of small conditional phase shifts induced by an interaction between ancilla and meter qubits. We utilize entangled photon pairs and implement the required three-qubit quantum logic circuit with linear optics. The circuit comprises a two-qubit controlled phase gate and a three-qubit controlled-controlled phase gate with fully tunable conditional phase shifts. We fully characterize the output states of our circuit by quantum state tomography and perform a comprehensive analysis of the trade-off between the measurement sensitivity and the success probability of the protocol. The observed experimental results are in good qualitative agreement with theoretical predictions, but the overall performance of our setup is limited by various experimental imperfections. We provide a detailed theoretical analysis of the influence of dephasing of the entangled ancilla state, which is one of the main sources of imperfections in the experiment. We also discuss the ultimate scaling with the dimension of the entangled ancilla system.

Wavelet-transform-based speckle vector tracking method for X-ray phase imaging.

We introduce a new X-ray speckle-vector tracking method for phase imaging, which is based on the wavelet transform. Theoretical and experimental results show that this method, which is called wavelet-transform-based speckle-vector tracking (WSVT), has stronger noise robustness and higher efficiency compared with the cross-correlation-based method. In addition, the WSVT method has the controllable noise reduction and can be applied with fewer scan steps. These unique features make the WSVT method suitable for measurements of large image sizes and phase shifts, possibly under low-flux conditions, and has the potential to broaden the applications of speckle tracking to new areas requiring faster phase imaging and real-time wavefront sensing, diagnostics, and characterization.

Dual-polarization single-chord plasma interferometry in stellarators/torsatrons

The well known ordinary wave based interferometry is of frequent use for plasma diagnostics in fusion facilities. With the probing direction being perpendicular to the magnetic field of the facility, the ordinary wave phase shift is proportional to the average density along the probing path at frequencies much higher than the plasma frequency of electrons. In the case of extraordinary waves, the phase shift depends on both the plasma density and the confining magnetic field. For the facilities of stellarator/torsatron types, the magnetic field is known; therefore, the measurement of the extraordinary wave phase shift can also provide information on the plasma density profile. The plasma density measurements with the use of dual-polarization interferometers were carried out on the Uragan-3M and Uragan-2M torsatrons. For correct interpretation of the experimental results, numerical simulation was performed to describe the probing wave propagation through the plasma in the magnetic field of variable direction. The transmitting-to-receiving horn scattering matrix has been obtained in a wide range of plasma parameters. In the course of the interpretation of measurements, restrictions on the use of the Wentzel-Kramers-Brillouin approximation were determined. This has made it possible to develop the optimized layout of the dual-polarization interferometer for measuring the plasma density in stellarators/torsatrons. The here proposed upgrade of the interferometers on Uragan-2M will enable one to obtain additional information on the temporal evolution of the plasma density.

An algorithm for automatic grasping an UHF RFID passive tag

This paper proposes an automatic system which allows a mobile robot to reach a tagged object in an unknown environment, exploiting the Radio Frequency IDentification (RFID) technology. It is assumed that the robot has an odometry system (e.g., wheel encoders) and an RFID reader which provides it with phase-shift measurements of the RFID signal backscattered by the tagged object. Since phases are ambiguous measurements of the tag-reader distance, a Multi-Hypothesis Extended Kalman Filter is proposed to on-line extract, by fusing phase measurements with odometry readings, the range and the bearing of the unknown tag. Once the relative position of the tag is known, a control algorithm is applied to drive the robot toward the desired destination. Numerical results are reported to illustrate the approach.

Influence of edge effects on laser-induced surface displacement of opaque materials by photothermal interferometry

We demonstrate the influence of edge effects on the photothermal-induced phase shift measured by a homodyne quadrature laser interferometer and compare the experiments with rigorous theoretical descriptions of thermoelastic surface displacement of metals. The finite geometry of the samples is crucial in determining how the temperature is distributed across the material and how this affects the interferometer phase shift measurements. The optical path change due to the surface thermoelastic deformation and thermal lens in the surrounding air is decoded from the interferometric signal using analytical and numerical tools. The boundary/edge effects are found to be relevant to properly describe the interferometric signals. The tools developed in this study provide a framework for the study of finite size effects in heat transport in opaque materials and are applicable to describe not only the phase shift sensed by the interferometer but also to contribute to the photothermal-based technologies employing similar detection mechanisms.

Laboratory demonstration of mini-MIGHTI: A prototype sensor for thermospheric red-line (630 nm) neutral wind measurements from a 6U CubeSat

The design and laboratory demonstration of a prototype sensor for measuring thermospheric red-line winds from a 6U CubeSat is described. The sensor uses the flight spare interferometer developed for the MIGHTI instrument on NASA's ICON satellite with a more limited scientific scope to enable it to fit within the limited volume of a 6U CubeSat. A performance model coupled with laboratory phase shift measurements demonstrate the capability of the sensor for thermospheric, atomic-oxygen, red-line wind measurements.

Phase-shift laser range finder technique based on optical carrier phase modulation.

A coherent laser range finder based on optical phase modulation and phase shift measurement is presented. In the proposed laser range finder, the emitted laser is modulated by an electro-optic phase modulator using a 20 MHz sine signal, and the received laser is mixed with a local oscillator using a 90° optical hybrid. Compared with traditional laser phase shift range finders, the proposed laser range finder can measure the velocity and range at high precision simultaneously. An algorithm to calculate the range and velocity is deduced. Our preliminary experiments on moving targets indicate that when the measurement rate is 100 kHz, the root mean square errors of range and velocity, respectively, are 9.35×10-4m and 4.74×10-4m/s.

CMUT Time of Flight Gas Sensor By Phase Shift Measurement

Introduction The most common approach to measure a gas concentration consists in coating the exposed part of a sensor with a functionalized film in order to absorb the targeted gas [1].However, it is well known that a sensitive coating compromises the long term stability of the sensor mostly due to aging of such film [2]. This has resulted in an increasing interest in uncoated sensors, which rely on the change of the physical properties (mass density for instance) of their surrounding gas despite their lack of selectivity.One example of uncoated sensors are time of flight sensors. Capacitive micromachined ultrasonic transducers (CMUTs) [3], have been previously used for time of flight gas sensing due to their easy integration capabilities. However, these methods rely on peak detection algorithms which can be very complex and hard to integrate.In this study, we present a new simple approach using the phase shift of a continuous ultrasonic wave to measure the time of flight between two CMUT arrays. The principle of this method along with the experimental setup and results will be presented in the following sections. Sensor Figure 1 shows a picture of the sensor used in this study. It consists of an array of thousands of CMUTs as the one illustrated in Figure 2 fabricated according to [4]. By applying a bias Vdc and an alternative voltage Vdc between its electrodes, the top electrode vibrates generating an ultrasonic mechanical vibration in the gas (emitter mode). Similarly, when the membrane vibrates due to a mechanical vibration of the gas, the CMUT’s capacitance changes generating an electrical signal (receiver mode). Principle The experimental setup schematics are shown in Figure 3. One CMUT array working as emitter (1) generates a continuous ultrasonic wave at a given angular frequency (ω) through a network analyzer in gain/phase configuration (2). The wave propagates through the gas at a velocity (C) that depends on the gas composition. For this study the gas consists of N2 (similar to air) and either CO2 or H2. In the case of an ideal gas, its expression is given by Equation 1 where R = 8.314 J.K-1.mol-1, T = 20°C, x is the molar fraction of a gas (either N2 or the mixture), M is the corresponding molar mass and γ is the adiabatic index given by Equation 2 where cp and cv are, respectively, the isobar and isochoric heat capacitance per unit mass. After a delay τ, the wave reaches a second CMUT array (3) working in receiver mode. The generated signal is conditioned by a charge amplifier (4) and then injected back to the network analyzer. At a given time t, the phase difference φ between the emission and the reception is proportional to τ as shown in Equation 3. Therefore, the slope of the curve φ(ω ) changes when the gas composition changes. To verify this experimentally, the curves φ( w) are shown for pure N2 (black), 4% of H2 in N2 (blue) and 4% of CO2 in N2 (green) in Figure 4. Results 1-Sensitivity Tests under H2 and CO2 in N2 at different concentrations (4%, 3%, 2% and 1%) were performed and are shown respectively in Figure 5 and Figure 6. From these measurements, the calibration curves were obtained with good linearity (Figure 7). The sensitivities (slope of the curves) to each gas were measured and their values are, respectively, S{H2,exp}=-92ns/% and S{CO2,exp}=55ns/%. Their corresponding theoretical values around a given concentration (xmix=4%) can be approximated by Equation 4. The obtained values are respectively, S{H2,th}=-135ns/% and S{CO2,th}=97ns/% which are consistent with the experiments. 2-Limit of Detection Finally, knowing the sensitivity to a gas Sgas , a theoretical limit of detection (LOD) can be estimated with Equation 5 where σ=1ns, is the noise standard deviation of the sensor. The obtained values for H2 and CO2 are, respectively, LODH2 =0.03%, LODCO 2 =0.05%.In order to verify this experimentally, tests at low concentrations for H2 and CO2 were performed and are shown, respectively, in Figure 8 and Figure 9. The obtained results are consistent with the calculations. Conclusion In this study we presented a new way of determining the concentration of binary gas mixtures without a sensitive chemical coating through a time of flight measurement. We verified this method using N2 as a reference and both CO2 and H2 as analytes. Finally, we showed experimentally that the LOD in N2 is less than 0.03% for H2 and less than 0.05% for CO2 which, despite being worse than what has been reported with a coated sensor, remain comparable to the state of the art of uncoated sensors and to some commercial coated sensors.

Detection of the phase curve and occultation of WASP-100b with TESS

ABSTRACT We report the detection of the full orbital phase curve and occultation of the hot-Jupiter WASP-100b using TESS photometry. The phase curve is isolated by suppressing low-frequency stellar and instrumental modes using both a non-parametric harmonic notch filter (phasma) and semi-sector long polynomials. This yields a phase-curve signal of (73 ± 9) ppm amplitude, preferred over a null-model by ΔBIC = 25, indicating very strong evidence for an observed effect. We recover the occultation event with a suite of five temporally localized tools, including Gaussian processes and cosine filtering. This allows us to infer an occultation depth of (100 ± 14) ppm, with an additional ±16 ppm systematic error from the differences between methods. We regress a model including atmospheric reflection, emission, ellipsoidal variations, and Doppler beaming to the combined phase-curve and occultation data. This allows us to infer that WASP-100b has a geometric albedo of $A_g = 0.16^{+0.04}_{-0.03}$ in the TESS bandpass, with a maximum dayside brightness temperature of (2710 ± 100) K and a warm nightside temperature of $(2380^{+170}_{-200})$ K. Additionally, we find evidence that WASP-100b has a high thermal redistribution efficiency, manifesting as a substantial eastward hotspot offset of $(71^{+2}_{-4})^{\circ }$. These results present the first measurement of a thermal phase shift among the phase curves observed by TESS so far, and challenge the predicted efficiency of heat transport in the atmospheres of ultra-hot-Jupiters.

Design and characterization of compact digital RF MEMS capacitors and phase shifters in CMOS 0.35 µm technology

This work reports on the design, fabrication and characterization of compact digital RF MEMS capacitors and phase shifters that are built in the back end of line (BEOL) of CMOS 0.35 µm technology. The devices are micromachined using a maskless post-processing sequence with cryogenic cooling on to control the out-of-plane warping of the metal-oxide structural layers. The implemented vertical electrostatic actuation in the developed post process allows the realization of highly compact designs of both devices, and an operating voltage of the devices is stay below 70 V. The 4-bit capacitors provide a measured tuning ratio close to 10:1 which corresponds to 0.15 pF to 1.2 pF over the frequency range 3–10 GHz. The overall footprint of the digital capacitor is 0.6 mm × 0.9 mm. The measured quality factor after de-embedding the losses due to the RF probing pads is up to 120. The measurement of the 4-bit phase shifters reveals low insertion loss <3 dB at 20 GHz along with low variation of the insertion loss <1 dB up to the same frequency. The measured phase shift is 150 at 20 GHz. The overall footprint of the 4-bit phase shifter is around 1 mm × 1 mm.

Snapshot phase-shifting lateral shearing interferometer

We propose a novel, low-cost snapshot phase-shifting lateral shearing interferometer (SPLSI) with full-range continuously adjustable lateral shear ratio. A tunable shear plate, consisting of a polarizing beam splitter (PBS) plate and a reflective mirror, separates the orthogonally polarization states of the test wavefront into original and sheared wavefronts. The lateral shear ratio can be tuned by adjusting the spacing between PBS plate and the mirror. A pixelated polarization camera simultaneously captures four π/2 phase-shifted interferograms for phase-shifting interferometric measurement. In addition to tunable shear ratio and snapshot capture of phase-shifted interferograms, one more key feature is that SPLSI can measure the wavefront of low-coherence light. The feasibility of the proposed system is demonstrated experimentally. The proposed system provides a simple, compact, and fast way to achieve the instantaneous phase-shifting lateral shearing interferometric testing of wavefronts with minimal impact from environmental disturbance.

Gouy phase shift measurement in a high-finesse cavity by optical feedback frequency locking

We demonstrate a simple and robust scheme to measure the relative position of transverse cavity modes with high precision. This is based on robust optical-feedback frequency locking of a diode laser to a cavity resonance. A fraction of the laser power is then frequency shifted and used to re-inject other cavity resonances to obtain their positions relative to the locking resonance. This delivers the Gouy phase shift of the cavity modes with precision down to rad, comparable to previous state of the art based on a more complex setup. This should also be of interest for high precision/accuracy measurement of distance and displacement.

ОСЦИЛОГРАФІЧНИЙ МЕТОД ВИМІРЮВАННЯ ФАЗОВОГО ЗСУВУ НА БАЗІ ДВОНАПІВПЕРІОДНОГО ПЕРЕТВОРЕННЯ

The subject matter of the article is the oscilloscope methods of measuring the phase shift of two harmonic signals, after carrying out their two-half-period transformation and summing. The goal is to develop ways to implement an oscilloscope method of measuring the phase shift of two harmonic signals, which will significantly reduce the component of measurement error caused by phase non-symmetry of the transmission channels, by reducing their length. Analyze the measurement error for each of the methods for determining the phase shift of two harmonic signals using their two-half-periodic transformation. The tasks: statement of measurement problem of determination of phase shift of two harmonic signals; analysis of known oscilloscope methods of phase shift measurement, development of methods for implementing the oscilloscope method based on the analysis of the characteristics of the total signal obtained during the two-half-period transformation; estimation of measurement errors for each method. The methods used are the methodology for estimating measurement errors in indirect measurements. The following results were obtained. Methods for implementing an oscilloscope measurement method using the total signal after a two-half-period transformation based on the analysis of temporal characteristics and local extrema of this signal are proposed. The list of measuring operations that implement each method is defined. The analysis of the components of measurement errors was performed and the degree of correlation was determined. Synthesized ratios for the calculation of measurement error. Conclusions. The scientific novelty of the obtained results is the following: an oscilloscopic method has been developed that will allow reducing substantially the component of the error caused by phase non-symmetry of the signal transmission channels; obtained ratios for the implementation of the oscilloscope measurement method using two-half-period conversion; obtained ratios to calculate the standard deviation of the total measurement error in each of the proposed methods.

Measurement of the total neutron-scattering cross-section ratios of noble gases of natural isotopic composition using a pulsed neutron beam

Precision measurements of slow neutron cross sections with atoms have several scientific applications. In particular the n-$^{4}$He s-wave scattering length is important to know both for helping to constrain the nuclear three-body interaction and for the proper interpretation of several ongoing slow neutron experiments searching for other types of neutron-atom interactions. We present new measurements of the ratios of the neutron differential scattering cross sections for natural isotopic-abundance mixtures of the noble gases He, Ar, Kr, and Xe to natural isotopic abundance Ne. These measurements were performed using a recently developed neutron scattering apparatus for gas samples located on a pulsed slow neutron beamline which was designed to search for possible exotic neutron-atom interactions and employs both neutron time of flight information and a position-sensitive neutron detector for scattering event reconstruction. We found agreement with the literature values of scattering cross sections inferred from Ar/Ne, Kr/Ne and Xe/Ne differential cross section ratios over the $q$ range of $1 - 7$ nm$^{-1}$. However for the case of He/Ne we find that the cross section inferred differs by 11.3% (7.6 $\sigma$) from previously-reported values inferred from neutron phase shift measurements, but is in reasonable agreement with values from other measurements. The very large discrepancy in the He/Ne ratio calls for a new precision measurement of the n-$^{4}$He scattering length using neutron interferometry.

Chiral Effective Field Theory Description of Neutrino Nucleon–Nucleon Bremsstrahlung in Supernova Matter

Abstract We revisit the rates of neutrino pair emission and absorption from nucleon–nucleon bremsstrahlung in supernova matter using the T-matrix formalism in the long-wavelength limit. Based on two-body potentials of chiral effective field theory (χEFT), we solve the Lippmann–Schwinger equation for the T-matrix including non-diagonal contributions. We consider final-state Pauli blocking and hence our calculations are valid for nucleons with an arbitrary degree of degeneracy. We also explore the in-medium effects on the T-matrix and find that they are relatively small for supernova matter. We compare our results with one-pion exchange rates, commonly used in supernova simulations, and calculations using an effective on-shell diagonal T-matrix from measured phase shifts. We estimate that multiple-scattering effects and correlations due to the random phase approximation introduce small corrections on top of the T-matrix results at subsaturation densities. A numerical table of the structure function is provided that can be used in supernova simulations.