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Item type:Publication, Perspective chapter: optimal analysis for the correlation between vibration and temperature through an intelligent sensor/transducer based in amorphous nanostructures to measure vibrating surfaces temperature(IntechOpen, 2022-12-02)The vibration is an oscillatory movement caused by a propagation of waves through fluids or solids, and this consequence is achieved in many mechanic systems by the energy transmission between the movement source with the machine that needs the transmission movement, such as the vibration produced by a combustion engine, by a compressor system and by a result of movement transmission over rotor systems. However, if it is not a controlled mechanism to moderate the produced decibels, the main system that is affected by the vibration can reduce its performance; moreover, it can increase the surface temperature of the vibrating source and systems around. In spite of this, when it uses contact sensors to measure the vibration and temperature over the surface vibrating system, the measured data are under disturbance caused by the vibration source. Therefore, in this research is proposed an intelligent sensor/transducer based in amorphous nanostructures owing to measure the vibration of the surface through infrared (IR) emitter/receiver and the absorbance of the receiver sample has a quite range of work and robustness under disturbance of vibrating signals. This proposed sensor also has the possibility to charge energy by itself because of sun/warmth energy conversion. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Nonlinearity parameter estimation method from fundamental band signal depletion in pulse-echo using a dual-energy model(Acoustical Society of America, 2025)The estimation of the nonlinearity parameter (B/A) has the potential to be used in the clinical diagnosis of conditions such as liver steatosis. Recently, a pulse-echo method to estimate B/A based on the theory of the fundamental band amplitude depletion of weak waves, namely, the depletion method, was proposed. In the present work, the depletion method is presented with more technical detail. Then, the robustness of the depletion method is assessed by using simulations that diverge from the model requirements: (1) monochromatic plane wave propagation and (2) quadratic power-law frequency dependence attenuation. Regarding requirement (1), the results led to a critical finding that when using wideband pulses (37%–113% bandwidth), the bias of the B/A estimates is larger than the bias obtained using narrowband pulses (11%–28% bandwidth), even if requirement (2) holds. Regarding requirement (2), power-law frequency dependence closer to those of soft tissues, i.e., 1.1 or 1.2, using narrowband pulses presented bias of less than 10%. The use of narrowband pulses also was shown to be robust when the reference phantom and sample had attenuation mismatches of around 60%. Finally, the experimental feasibility of the depletion method was evaluated, showing results with good accuracy (bias <17%), which are consistent with the observations in the simulations.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Spatially Weighted Fidelity and Regularization Terms for Attenuation Imaging(Institute of Electrical and Electronics Engineers Inc., 2025)Quantitative ultrasound (QUS) holds promise in enhancing diagnostic accuracy. For attenuation imaging, the regularized spectral log difference (RSLD) can generate accurate local attenuation maps. However, the performance of the method degrades when significant changes in backscatter amplitude occur. Variations in the technique were introduced involving a weighted approach to backscatter regularization, which, however, is not effective when changes in both attenuation and backscatter are present. This study introduces a novel approach that incorporates an L1-norm for backscatter regularization and spatially varying weights for both fidelity and regularization terms. The weights are calculated from an initial estimation of backscatter changes. Comparative analyses with simulated, phantom, and clinical data were performed. When changes in backscatter and attenuation occur, the proposed approach reduced the lowest root mean square error by up to 73%. It also improved the contrast-to-noise ratio (CNR) by a factor of 4.4 on average compared with previously available methods, considering the simulated and phantom data. In vivo results from healthy livers, thyroid nodules, and a breast tumor further confirm its effectiveness. In the liver, it is shown to be effective at reducing artifacts of attenuation images. In thyroid and breast tumors, the method demonstrated an enhanced CNR and better consistency of the attenuation measurements with the posterior acoustic enhancement. Overall, this approach offers promise for enhancing ultrasound attenuation imaging by helping differentiate tissue characteristics that may indicate pathology.1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Quad-Active-Bridge Resonant-Type Single-Stage Three-Phase AC-DC Converter: Modulation and Control for V2G Applications(Institute of Electrical and Electronics Engineers Inc., 2025)The single-stage (SS) ac–dc converter is a promising solution for bidirectional electric vehicle chargers (BEVCs) due to its smaller volume, higher efficiency, and durability compared with the two-stage ac–dc converter. Nevertheless, typically SS ac–dc structures implement highly complex modulation schemes because most of them use bipolar voltage switches. In this article, a novel modulation and control strategy is introduced for the SS quad-active-bridge resonant-type ac–dc converter, which only uses unipolar voltage switches. In the proposed modulation, grid voltages are modulated by duty ratio (DR), whereas the dc source voltage is modulated by phase-shift (PS) and DR. The PS angle takes a constant value according to grid currents amplitude. Moreover, the DR angles, used to modulate grid voltages, control the sinusoidal shape of grid currents according to proportional-integral-resonant controllers cascaded to a second-order low-pass filters and an active damping. Whereas, the DR angle, used to modulate the dc source voltage, is applied to reduce the high-frequency current, in case of reactive power transfer to the grid. Experimental results from a 1.5 kW prototype show high efficiency (96.4%), bidirectional active-reactive power transfer capability, and low harmonic distortion in the grid currents (1.1%), making it an ideal alternative for BEVCs.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Multi-Frequency Regularized Approach for Simultaneous Estimation of the Acoustic Nonlinearity Parameter and Attenuation Coefficient(IEEE Computer Society, 2025)The acoustic nonlinearity parameter (B/A) could enhance conventional ultrasound diagnostics in diseases associated with changes in fat tissue content. Recently, a simultaneous estimator of the B/A and the attenuation coefficient (AC) in pulse-echo was introduced, which was based on fitting measurements derived from backscattered data from a dual-energy model to a nonlinear model using the Gauss-Newton Levenberg-Marquardt algorithm (GNLM). However, the GNLM algorithm presented high sensitivity to the initial guess values. This paper improves the Gauss-Newton method by using data from several tone-burst transmissions at different center frequencies rather than only one narrowband tone-burst. In addition, it is combined with a total variation regularization approach (GNTV). The results in simulated and experimental phantoms suggest that incorporating regularization and increasing the number of transmission frequencies improves robustness compared to the GNLM method by accurately estimating B/A values (mean relative error less than 13% in the experiments).1