The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Ferran Martin - One of the best experts on this subject based on the ideXlab platform.
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Phase-Variation Microwave Sensor for Permittivity Measurements Based on a High -Impedance Half-Wavelength Transmission Line
IEEE Sensors Journal, 2021Co-Authors: Jonathan Munoz-enano, Paris Velez, Marta Gil, Pau Casacuberta, Ferran MartinAbstract:A phase-variation microwave sensor operating in transmission and implemented by means of a high-impedance half-wavelength Sensing Line is reported in this paper. The sensor is useful for dielectric constant measurements and dielectric characterization of materials. By forcing the electrical length of the Sensing Line to be a half-wavelength when it is loaded with the so-called reference (REF) material, perfect matching is obtained regardless of the characteristic impedance of the Line. This fact can be used to enhance the sensitivity for small perturbations, by merely increasing the characteristic impedance of the Sensing Line. An exhaustive analysis that supports such conclusion is reported in the paper. Then, two prototype sensors are designed and fabricated for validation purposes. As compared to the ordinary phase-variation permittivity sensor implemented by means of a matched (50-Ω) Line with identical length, the sensitivity for small perturbations in the proposed sensor is 2.1 times larger. Further advantages of these sensors are low-cost, small size, implementation in planar technology, and very simple design and fabrication, derived from the fact that the Sensing region is a half-wavelength transmission Line.
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Highly Sensitive Phase Variation Sensors Based on Step-Impedance Coplanar Waveguide (CPW) Transmission Lines
IEEE Sensors Journal, 2021Co-Authors: Jonathan Munoz-enano, Paris Velez, Marta Gil, Pau Casacuberta Orta, Ferran MartinAbstract:Reflective-mode step-impedance transmission Line based sensors for dielectric characterization of solids or liquids have been recently proposed. In this article, in order to further increase the sensitivity, the sensor is implemented in coplanar waveguide (CPW technology), and this constitutes the main novelty of this work. The sensor thus consists of a high-impedance 90° (or low-impedance 180°) open-ended Sensing Line cascaded to a low-impedance 90° (or high-impedance 90°) Line. The output variable is the phase of the reflection coefficient, which depends on the dielectric constant of the material under test (MUT), the input variable. Placing a MUT on top of the Sensing Line causes a variation in the effective dielectric constant of the Line, thereby modifying the phase of such Line. This in turn produces a multiplicative effect on the phase of the reflection coefficient, by virtue of the step-impedance discontinuity. The main advantage of the CPW-based sensor, over other similar sensors based on microstrip technology, is the stronger dependence of the phase velocity of the Sensing Line with the dielectric constant of the MUT, resulting in sensitivities as high as −45.48° in one of the designed sensors. The sensor is useful for dielectric characterization of solids and liquids, and for the measurement of variables related to changes in the dielectric constant of the MUT (defect detection, material composition, etc.).
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On the Sensitivity of Reflective-Mode Phase-Variation Sensors Based on Open-Ended Stepped-Impedance Transmission Lines: Theoretical Analysis and Experimental Validation
IEEE Transactions on Microwave Theory and Techniques, 2021Co-Authors: Jonathan Munoz-enano, Paris Velez, Marta Gil, Pau Casacuberta, Ferran MartinAbstract:This article presents an exhaustive study of the sensitivity in reflective-mode phase-variation sensors based on an open-ended transmission Line with a step-impedance discontinuity. Such discontinuity delimits the Sensing region (which extends up to the open end of the so-called Sensing Line), from the transmission Line section connected to the input port (design Line), which is used to enhance the sensitivity. The theoretical analysis provides the design guideLines to achieve a sensor with high sensitivity compared with the one based on an ordinary (uniform) Line with a similar length. In particular, it is shown that for sensitivity optimization, the electrical length of the design Line must be set to 90° (or an odd multiple), whereas either a 90° (or an odd multiple) or a 180° (or an even or odd multiple) Sensing Line can be alternatively used in order to maximize the sensitivity. It is shown that the impedance contrast, defined as the ratio between the characteristic impedances of the design and Sensing Line, is a key parameter for sensitivity enhancement, and it must be as low or as high as possible for the 90° or 180° Sensing Lines, respectively. For validation purposes, two prototype devices (one with a 90° and the other one with a 180° Sensing Line) have been designed and fabricated following the design guideLines. Such devices have been tested by loading the Sensing region with several materials with different dielectric constants. Compared with the ordinary Line-based sensors, it is found that the maximum sensitivity is enhanced by a factor of 19.7 and 11.4 in the phase-variation sensor based on a 90° and 180° Sensing Line, respectively. Finally, the sensor concept is generalized to a multisection step-impedance transmission Line as a means of further increasing the sensitivity, and a prototype device exhibiting 528.7° maximum sensitivity is implemented.
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Open-Ended-Line Reflective-Mode Phase-Variation Sensors for Dielectric Constant Measurements
2020 IEEE SENSORS, 2020Co-Authors: Jonathan Munoz-enano, Paris Velez, Marta Gil, Pau Casacuberta, Ferran MartinAbstract:This paper reports a detailed analysis of reflective-mode phase-variation sensors based on open-ended microstrip Lines. These sensors are useful for measuring dielectric constants or other variables related to it (e.g., material or liquid composition). For that purpose, the so-called material under test (MUT) should be placed on top of the open-ended Line, the Sensing region. A change in the dielectric constant of the MUT modifies the electrical length and the characteristic impedance of the Sensing Line, thereby varying the phase of the reflection coefficient, the output variable. The analysis provides the optimum conditions for sensitivity optimization. It is concluded that either high-impedance 90° or low-impedance 180° Sensing Lines are needed in order to obtain a strong dependence of the phase of the reflection coefficient with the dielectric constant of the MUT. Such conclusions are validated by electromagnetic simulations and experiments.
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a reflective mode phase variation displacement sensor
IEEE Access, 2020Co-Authors: Jonathan Munozenano, Paris Velez, Marta Gilbarba, Ferran MartinAbstract:In this paper, a displacement sensor based on an open-ended step-impedance transmission Line is reported. The sensor operates in reflection, and the output variable is the phase of the reflection coefficient. The static part of the sensor is the step-impedance transmission Line, where the open-ended Line section is the sensitive part (Sensing Line). The movable part is a dielectric slab, e.g., an uncladded microwave substrate. When such slab, located on top of the Sensing Line, is in relative motion to the Line, in the direction of the Line axis, the portion of the Sensing Line covered by the slab varies, and this results in a change in the phase of the reflection coefficient of the Line. The step impedance discontinuity contributes to optimize the sensor sensitivity, the key parameter. A detailed analysis providing the design guideLines is carried out and used to design a prototype displacement sensor. The characterization of the fabricated device points out the potential of the approach to implement highly sensitive displacement sensors. The sensor is a one-port device and operates at a single frequency.
Jin Jiang - One of the best experts on this subject based on the ideXlab platform.
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Using the noise analysis technique to detect response time problems in the Sensing Lines of nuclear plant pressure transmitters
Progress in Nuclear Energy, 2010Co-Authors: Hashem M. Hashemian, Jin JiangAbstract:Abstract Blockages, voids, and leaks contribute to nearly 70 percent of the age-related problems in the Sensing Lines that connect pressure, level, and flow transmitters in nuclear plants to the processes they measure, reducing their speed of response. Only the noise analysis technique provides an effective means for testing response times when a nuclear plant is operating. It also makes possible the simultaneous testing of response time of multiple pressure transmitters and is applicable for both force-balance and motion-balance transmitter types. The technique involves three steps -- data acquisition, data qualification, and data analysis. Commercial signal-conditioning equipment is used to extract the noise from the transmitter output by removing the DC component of the signal and amplifying the AC component. The AC signal is then digitized; qualified for stationarity, Linearity, and other abnormalities; and then analyzed in the frequency domain and/or time domain. Tests performed by the author has validated the accuracy of the noise analysis technique and yielded the following conclusions: Long Sensing Lines and blockages increase the response time of a pressure Sensing system. Increases in response times caused by Sensing-Line length and blockages depend on the compliance of the transmitter. The response time of transmitters with larger compliances is more sensitive to Sensing-Line length and blockages than that of transmitters with small compliances. When noise analysis identifies a Sensing-Line blockage, the Line must be purged (flushed) and noise tests repeated to ensure the problem is resolved.
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pressure transmitter accuracy
Isa Transactions, 2009Co-Authors: Hashem M. Hashemian, Jin JiangAbstract:This paper discusses the key causes of calibration drift in pressure transmitters and procedures for calibrating pressure transmitters to ensure their accuracy. Calibrating pressure transmitters involves adjusting the potentiometers in the sensor that controls the zero (lowest pressure at which a transmitter is calibrated) and span (the range of pressure the transmitter is to indicate) of the transmitter. The initial or bench calibration of pressure transmitters involves using a constant pressure source such as a deadweight tester. Once the transmitters are installed, temperature, pressure, humidity, vibration, maintenance activities, and normal aging can degrade their accuracy. Transmitter accuracy can also be degraded by transmitter Sensing Lines, when the water in a Sensing Line reference leg boils off, when non-condensable gases in the reference leg dissolve, and when voids, blockages, freezing, or leakage occur in Sensing Lines. On-Line calibration techniques enable plants to avoid these accuracy problems by monitoring the output of an individual transmitter.
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Pressure-Sensing Line Problems and Solutions
Power, 2009Co-Authors: H. M. Hashemian, Jin JiangAbstract:Improper pressure-Sensing Line design or installation is often found to be the cause of poor Sensing system accuracy and response time. Here's how to identify and solve those pesky pressure sensor problems in short order.
Dirk Heider - One of the best experts on this subject based on the ideXlab platform.
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Smart tooling with integrated time domain reflectometry Sensing Line for non-invasive flow and cure monitoring during composites manufacturing
Composites Part A: Applied Science and Manufacturing, 2013Co-Authors: Gaurav Pandey, Hope Deffor, Erik T. Thostenson, Dirk HeiderAbstract:An electrical transmission Line integrated into composite tooling has been developed to facilitate non-contact multipoint flow and cure monitoring during vacuum assisted resin transfer molding processing. The sensor is made of conductive aramid (Kevlar®) fibers and is an integral part of the glass fiber composite tooling. Electrostatic simulations in COMSOL® have been performed to optimize the wire spacing maximizing the sensitivity of the electric time domain reflectometry measurements. Tooling with integrated wires placed with optimal spacing has been fabricated. TDR flow monitoring experiments with the integrated sensor have been conducted and compared visually using digital image processing. TDR data obtained from the same sensor also enables measurement of the resin cure state. Fast and slow curing resin systems have been studied using the transmission Line integrated tooling and differential scanning calorimetry experiments have been performed to validate the cure measurements obtained from TDR. Major benefits of the sensor implementation include elimination of ingress/egress issues associated with standard sensor integration into composite tooling as well as reduced maintenance of the non-contact solution.
Jesús Blázquez - One of the best experts on this subject based on the ideXlab platform.
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The Hilbert transform as a quality control tool in capacitive pressure transmitters
Mechanical Systems and Signal Processing, 2010Co-Authors: C. Montalvo, Jesús Blázquez, A. García-berrocal, M. BalbásAbstract:Abstract The capacitive pressure transmitters consist of an isolating diaphragm connected to a Sensing Line through some inner tubes which contain silicone oil. The accuracy of the sensor is determined by the efficiency of the filling process with silicone oil in the transmitter inner chambers, so that the fact of not filling completely any of the transmitter chambers can affect the dynamic response of it. In fact, the oil loss syndrome is one of the most important breakdowns, since the sensor dynamic behaviour is no longer Linear. In this work the Hilbert transform is applied to detect the non-Linearity in the sensor response to a sinusoidal pressure wave. Such sensor suffers the oil loss syndrome at an incipient phase. The ill sensor is compared with a Linear one and the efficiency of the analysis is proved for the detection of a non-Linear behaviour as opposed to the traditional methods based on Fourier analysis. At last, a non-Linear model taken from literature is validated with empirical data.
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non Linear noise analysis from a capacitive pressure transmitter
Mechanical Systems and Signal Processing, 2004Co-Authors: A Garciaberrocal, Jesús Blázquez, J.m. Chicharro, M. BalbásAbstract:Abstract When the capacitive pressure transmitters—Rosemount type—experience a silicone oil-loss from its inner structure, they do not behave as a Linear dynamical system. Such an anomaly is reflected on the noise signal. In this work, a non-Linear model for the sensor and the Sensing Line is defined. It explains the main features of the noise signal as measured in service and in the laboratory.
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Pressure transmitter surveillance : the dominant real pole case
Progress in Nuclear Energy, 1995Co-Authors: Jesús Blázquez, Jesús BallestrínAbstract:Abstract There are about 500 pressure transmitters in a Nuclear Power Plant. Due to Safety requirements, some of them must be specially surveilled. Sensor response time to a pressure ramp is the usual quantity to be measured. Response time, τ r , reflects the dynamics of the sensor and the Sensing Line. A real pole is due to the inner sensor structure, but the complex pole stands for the Sensing Line too. The real pole usually is the dominant in most sensors. On Line monitoring noise analysis regards simultaneously both, the sensor and the Sensing Line, but the noise signal contains not only the sensor poles, but many others coming from the Plant, so must be conditioned previously and the determination of τ r is not free of systematic errors. That is the price to be paid for non disturbing the Plant. When the real pole is dominant, the Sensing Line contribution is negligible, so the on Line noise monitoring methods are supported by the laboratory experiments and the real pole border in the PSD is properly identified. The mean square frequency results proportional to τ r −1 , so manual techniques are designed for response time surveillance made by non noise Plant's maintenance technicians.
M. Balbás - One of the best experts on this subject based on the ideXlab platform.
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Application of the Monte Carlo Method for Capacitive Pressure Transmitters Surveillance in Nuclear Power Plants
Journal of Dynamic Systems Measurement and Control, 2012Co-Authors: C. Montalvo, A. García-berrocal, J. Blázquez, M. BalbásAbstract:In nuclear power plants (NPPs), according to current regulations, the response time of capacitive pressure transmitters is used as an index for surveillance. Such measurement can be carried out in situ applying the noise analysis techniques to the sensor output signal. The method is well established, and it is based on the autoregressive (AR) fitting optimized by the Akaike criterion (AIC). The sensor response is influenced by the Sensing Line, and its length is different in each plant. Recent empirical research has proved that the sensor inner structure can be modeled with a two real poles transfer function. In the present work, it has been proved that the noise analysis applied to the simulated response of a transmitter, modeled with two poles coupled with a Sensing Line, gives erroneous values for the ramp time delay when the Sensing Line is long. Specifically, the order of the AR model supplied by the Akaike criterion is not appropriate. Therefore, a Monte Carlo method is proposed to be applied in order to establish a new criterion, based on the statistical analysis of the repeatability of the ramp time delay obtained with the AR model.
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The Hilbert transform as a quality control tool in capacitive pressure transmitters
Mechanical Systems and Signal Processing, 2010Co-Authors: C. Montalvo, Jesús Blázquez, A. García-berrocal, M. BalbásAbstract:Abstract The capacitive pressure transmitters consist of an isolating diaphragm connected to a Sensing Line through some inner tubes which contain silicone oil. The accuracy of the sensor is determined by the efficiency of the filling process with silicone oil in the transmitter inner chambers, so that the fact of not filling completely any of the transmitter chambers can affect the dynamic response of it. In fact, the oil loss syndrome is one of the most important breakdowns, since the sensor dynamic behaviour is no longer Linear. In this work the Hilbert transform is applied to detect the non-Linearity in the sensor response to a sinusoidal pressure wave. Such sensor suffers the oil loss syndrome at an incipient phase. The ill sensor is compared with a Linear one and the efficiency of the analysis is proved for the detection of a non-Linear behaviour as opposed to the traditional methods based on Fourier analysis. At last, a non-Linear model taken from literature is validated with empirical data.
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non Linear noise analysis from a capacitive pressure transmitter
Mechanical Systems and Signal Processing, 2004Co-Authors: A Garciaberrocal, Jesús Blázquez, J.m. Chicharro, M. BalbásAbstract:Abstract When the capacitive pressure transmitters—Rosemount type—experience a silicone oil-loss from its inner structure, they do not behave as a Linear dynamical system. Such an anomaly is reflected on the noise signal. In this work, a non-Linear model for the sensor and the Sensing Line is defined. It explains the main features of the noise signal as measured in service and in the laboratory.
