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Formation of irregularities on the inner surface of pipes is a common phenomenon that leads to corrosion and affects the functionality in the processing industries. Ultrasonic is known as one of the non-destructive means to address the formation of irregularities inside pipes. In this study, an ultrasonic measurement system is developed to detect the presence of internal irregularities in a pipe. An ultrasonic sensor EFC16T/R-2 with a frequency of 40 kHz was mounted outside the test pipe with a circular ring sensor unit. Different conditions of the inner pipe surface had caused fluctuations of the ultrasonic signal. The results show a low output voltage in the range of 2.1333 to 3.1334 V when no irregularities were detected. A higher output voltage was observed in the range of 5.4677 to 8.8667 V when irregularities occurred. The reconstructed images of irregularities had matched the actual condition of the pipe. Some images showed a slight inaccuracy of the position of the irregularities caused by the instability of the ultrasonic signals. Overall, the developed ultrasonic tomography is suitable as a tool for monitoring irregularities in a pipe. Key words: Ultrasonic, non-destructive method, pipe irregularities, tomography, instrumentation

Ultrasonic tomography (UT) is an available method for processing monitoring. In this study, a novel dual-excitation method (DEM) for ultrasonic tomography for improving imaging quality is proposed. The DEM was defined and explained first in the study. Two typical bubble flow patterns were established to evaluate the effectiveness of the method using linear back projection (LBP) and fan-shaped LBP (FLBP). In order to quantitatively analyze the imaging quality, the image correlation coefficient (ICC) and the position error (PE) were chosen as two evaluation indexes. For two different bubble flow patterns with a 16-transducer UT system, the ICCs were improved by 13% and 15%, whereas the PEs were reduced by 19% and 4% by the DEM, respectively. Then, the influence of the noise was discussed. Thereafter, two postimaging methods, such as the sum-imaging method (SIM) and the multiplication-imaging method (MIM), were proposed and applied to further enhance the imaging quality. Compared with the original imaging quality, the PEs were reduced by 28% and 6% for the two different bubble flow patterns. The results indicated that the DEM could significantly improve the imaging quality, especially when MIM is assisted for image reconstruction.

Ultrasonic inspection of through-transmission is limited due to the inability to obtain defect depth information. Loss of signal is used as the only indicator, providing lateral defect information. This is often a problem in ultrasonic inspection. Radiographic acquisition techniques, where the X-ray source acts as the transmitter and the detector as the receiver, are conceptionally similar to ultrasonic through-transmission. In the latter, the tomography back-projection method is used to reconstruct images of an object that has been subjected to a minimum of 180° of rotation, to allow for full coverage of the item. In this paper, a novel approach based on back-projection is presented to improve image resolution and defect detectability. Two ultrasonic transducers in through-transmission configuration are utilised to capture data for image processing. The rotation of the transmitter and receiver is not possible in this set-up and, therefore, the reconstruction relies on the artificial generation of a limited rotation. Two probes are aligned either side of the material and are used to gather the ultrasonic signals. These signals are processed before the reconstruction algorithm is applied to them. Various processing and imaging reconstruction algorithms are explored, building on the basic back-projection method to obtain images that are better focused. This technique could be used within materials where there are high attenuation levels and, therefore, traditional pulse-echo is not feasible.

In ultrasonic tomography that employs the technique of digital focusing with an antenna (DFA), the problem of increasing the inspection performance is inextricably linked with the problem of increasing the speed of producing synthesized images. This problem can be effectively solved by concurrently using several approaches aimed at increasing the image production speed. In the framework of this paper, we consider the algorithm of nonuniform fast Fourier transform (NUFFT). The NUFFT can be used in the existing computationally efficient spatiotemporal processing algorithms with calculations in the frequency domain and is capable of correctly reconstructing synthesized images with sparse and non-uniform antenna arrays (AAs). The experimental data obtained indicate the ability of the NUFFT-based algorithm to restore synthesized images with high resolution.

Two-phase flow widely exists in the process industry, where ultrasonic tomography provides reliable visualization with benefits of noninvasion, nonradiation, and low-cost. To provide real-time reconstruction of low acoustic impedance contrast medium distribution existed in two-phase flow, a novel approach using continuous-wave excitation is proposed. With the basic measurement model introduced, a subspace filtered reconstruction algorithm is introduced with improvements on both accuracy and speed. Through nonuniform shape constrained range filter, the relative image error (RE) is reduced by 32.94% and 33.03% compared to simultaneous algebraic reconstruction technique (SART) and filter back projection (FBP) methods. Through derivation of offline iteration/online reconstruction (OIOR) method and truncated singular value decomposition (TSVD), the computing speed increases to 122 frame/s, which fits the requirement of online monitoring. A prototype of the measurement system is introduced with improved design of bipolar high-voltage excitation module and fan-beam angle piezoelectric transducers. Qualitative and quantitative results show that the proposed method has better image accuracy compared to conventional methods.

Numerical and physical simulations of cross-hole ultrasonic tomography of bored piles were carried out to specify the data acquisition and inversion procedures. Geometrical dimensions of defects specified in the models were reconstructed. Present techniques can be applied to integrity testing of reinforced concrete structures in field.

The DataSet contains the results of the mechanical behaviour of a concrete cube with dimensions 70 x 70 x 70 cm3under the splitting test. Three cubes were tested: cube 1 (concrete with polymer fibres), cube 2 (concrete with steel fibres) and cube 3 (plain concrete).

A non-destructive testing system requires multiple system configuration parameters during the operation process. For a given transducer, scanning frequency and number of measurements for averaging are just among those parameters. This work tests the central limit theorem to optimally set these parameters. The authors have designed a compact ultrasound computer tomography scanner from scratch just to test this criterion. It is shown that optimal frequency value changes with respect to the scanning angle for an object with a heterogeneous inner profile. The proposed criterion helps to estimate the multi-spectral combination before the recovery stage minimum error. Possible industrial applications of such a system are 2D/3D multiphase flow profile recovery or crack detection in the composite matter, non-invasively.

Two-phase flow is a regime that commonly existed in many applications of process industry, on which the technique of ultrasonic tomography (UT) could provide reliable measurement with benefits of non-invasion, non-radiation and low-cost. In order to provide considerable visualization of low acoustic impedance contrast configurations in two-phase flow, a regular weighted simultaneous algebraic reconstruction technique (RW-SART) using continuous-wave excitation is proposed and presented in detail. With measurement strategy and formulized reconstruction model introduced, the measurement system is introduced with modification on continuous-wave excitation module and fan-beam angle transducers. A regularized weighted least square (RWLS) framework combining total variation (TV) regularization and SART reconstruction is derived and presented in detail to address the problem that under-determined and ill-conditioned situation couldn’t be resolved simultaneously. Both numerical simulation and experimental investigation are conducted to validate the feasibility of continuous-wave excitation and the improvement of proposed reconstruction strategy, from which the distribution of oil-water two-phase flow is effectively reconstructed. The implementation of measurement system provides an option of continuous high-voltage excitation and measurement in UT. By utilizing both the geometric information and penalty constraint, the proposed reconstruction approach provides a framework that introduces regularization information to the algebraic iteration reconstruction. Consequently, it has better reconstruction result than TV, Landweber, L1, filtered back projection (FBP) and SART method.

In the lightweight material industries, the current focus is on fiber-reinforced plastics, in particular on carbon fiber-reinforced plastics (CFRPs), since they offer higher relative specific tensi...

In this research, determination of the applicable ultrasonic sensors based on the wall thickness of the metal pipe for the purpose of transmission tomography is studied. The range of applic...

23 páginas, 24 figuras, 1 tabla, A new versatile and geometrically reconfigurable ultrasonic tomography system (UTS) has been designed to inspect and obtain information about the internal structure and inner damage of columns in heritage buildings. This nondestructive system is considered innovative because it aims to overcome common limitations of existing systems. Tomographic inspections are typically carried out manually and are thus limited to small portions of construction elements. The proposed UTS allows the automatization of the inspection and the generation of numerous tomographic slices along the height of the column. It is valid for multiple types of columns and materials. In the present work, the system was tested on two limestone columns of the north façade of the Convent of Carmo in Lisbon, Portugal. The UTS is composed of a mechanical and an electronic system. The mechanical system consists of four linear motion subsystems mounted in a square setup. A transducer is placed on each of the axes, acting as emitter or receiver of the ultrasonic signals. The mechanical system also includes a guide system to adapt the inspections to the complex geometry of the columns. The electronic system allows the control and the synchronization of the movements and the emission/reception configuration of the four ultrasonic transducers, This research was funded by Creative Europe for cross-sectoral bridging culture and audio- visual content through digital, grant number 614719-CREA-1-2019-1-PT-CROSS-SECT-INNOVLAB

In chemical and food industry, the fluid concentration distribution inspection plays a key role in the control of the production processes. To meet the requirement of process control and by-product reaction suppression in chemical and food industry, advanced fluid concentration measurement techniques are highly desired. Due to its nondestructive and non-radiation features, Ultrasonic tomography (UT) is considered as a promising technique for monitoring the sucrose solution in the container, yielding images of both sound velocity and concentration. In this paper, we investigate the potential of using ultrasound tomography for quantitative fluid concentration imaging. Theoretical Basics of ultrasound tomography are studied, emphasizing aspects of tomographic forward problem, time-of-flight estimation, and the tomographic reconstruction algorithm. The feasibility and effectiveness of the developed methods are validated in numerical simulations.

The current quality detection methods for building materials concrete are inaccurate in the processing results of sound waves and amplitude signals, resulting in low accuracy of the propagation velocity and wave velocity dispersion in the detected concrete, and inaccurate quality strength detection results, so based on ultrasonic tomography technology The characteristics of the design of construction materials concrete quality inspection methods. Collect ultrasonic velocity and amplitude signals, and eliminate the abnormal signals in the collected sound velocity and amplitude; make full use of the ultrasonic tomography technology in the internal propagation of the medium, and the characteristics of digital imaging, complete the image transformation, establish the concrete mathematical model, output the internal image of concrete, and complete the concrete quality detection. Experimental results: The proposed construction material concrete quality inspection method, when inspecting the construction material concrete, the dispersion of the propagation velocity and the wave velocity in the detected concrete, compared with other inspection methods, the construction material concrete quality inspection method The result is more accurate.

As an important part of Process Tomography (PT), Ultrasound Tomography (UT) has the advantages of no invasion, no radiation, and low cost. However, UT systems are usually physically limited by the transmitter's emission angle of the transducer, and only three to five receiving transducers which are opposite the excitation transducer can receive the signal. This limitation will lead to insufficient prior information, insufficient data utilization, and severe reconstructed image artifacts, which will affect its practical application. In order to improve the accuracy of reconstruction, a multi-channel Convolutional Neural Network (CNN) method is proposed. The main structure of the U-net network, input of the network has two channels: channel one is the image reconstructed by traditional algorithm, and channel two is the measured voltage value. The training database contains 23,355 samples. After 235 epochs of training, the correlation coefficient of verification set is 0.85 and compared with LBP and SART, the proposed model has better reconstruction results.

An efficient domain decomposition method and its parallel implementation for the solution of the Helmholtz equation in three-dimensional layered media are considered. A modified trilinear finite el...

Assessing internal decay in tree trunks can be of crucial importance for industrial, environmental and public safety reasons [1]. To this effect, non-destructive testing (NDT) methods can provide information on the structural condition of trees with minimum intrusion. In this work, authors have analysed the capabilities of ultrasonic tomography in evaluating the internal structure of living trees, with a special focus on the identification of internal decay areas and tree bark inclusions.The presented ultrasonic tomography provides an image of the distribution of the ultrasonic velocity of propagation within the investigated section of a mature horse chestnut (Aesculus hippocastanum). This technique has proven its viability to detect fungal decomposition [2]. However, there exist some open issues with regard to: a) the coupling of the transducers to the tree, b) the anisotropy of the wood, c) the signal attenuation and the resolution of the tomographic inversion. To overcome these challenges, research is underway to explore the integration and new data-fusion strategies with other NDT methods, such as ground penetrating radar (GPR), which have proven their effectiveness within this area of endeavour [3].Within this context, data have been obtained from a “diseased” horse chestnut tree located at the Kensington Gardens – The Royal Parks – in London, UK, using two different ultrasonic equipment, i.e., the PICUS Sonic Tomograph and the Arbotom Sonic Tomograph. After compilation of data, the tree was felled and cut at the two sections where ultrasonic tomography tests were performed. In more detail, 12 sensors were arranged around the perimeter of the tree in compliance with the manufacturer’s recommendations concerning the inspection methodology (sensors installed within the bark of the tree without any intrusion to the core of the tree). The adopted methodology takes to account the shape and size of the trunk [1]. The processed data were mapped against the cut sections of the tree for validity purposes. Results presented in this abstract are part of a major ongoing research project that the authors have undertaken for the last three years. AcknowledgementsThe authors would like to express their sincere thanks and gratitude to the following trusts, charities, organisations and individuals for their generosity in supporting this project: Lord Faringdon Charitable Trust,The Schroder Foundation,Cazenove Charitable Trust,Ernest Cook Trust,Sir Henry Keswick,Ian Bond, P.F. Charitable Trust,Prospect Investment Management Limited,The Adrian Swire Charitable Trust,The John Swire 1989 Charitable Trust,The Sackler Trust,The Tanlaw Foundation, and The Wyfold Charitable Trust. We would like to thank also Ian Rodger – Royal Parks Arboricultural Manager– for providing us with the tested tree. This paper is dedicated to the memory of our colleague and friend Jonathan West, one of the original supporters of this research project. References[1] Gilbert, G.S. et al. (2016). Use of sonic tomography to detect and quantify wood decay in living trees, Applications in Plant Sciences 4(12): 1600060.[2] Bucur, V. Acoustics of Wood. CRC Press Inc., Boca Raton,Argentina (1995).[3] Alani, A.M. et al. (2019). The Use of Ground Penetrating Radar and Microwave Tomography for the Detection of Decay and Cavities in Tree Trunks. Remote Sensing 11: 2073.

This study is aimed to determine the influence of the parameters relevant for the application of ultrasonic tomography in the field of grouting quality evaluation. The parameters tested were the wave velocity difference between concrete and grout (VDCG), the type of material used for a pipe, and the type of pre-stressed tendon within the pipe. Fourteen cube specimens were constructed, and a theoretical model was used to analyse the effects of these parameters. The results show that these parameters affect each other on the detection effectiveness of ultrasonic tomography, and that VDCG affects it most. It was found that ultrasonic tomography is suitable for the evaluation of grouting quality in post-tensioned structures when VDCG is small and the type of tendon used is a steel bar.

Post-tensioning systems provide safe and efficient construction solutions for long span bridges. Despite the improved grouting practices over the past decade, existing post-tensioning systems may have significant amount of grout defects, which could lead to corrosion of the strands. Condition assessment of post-tensioning systems is necessary to allow bridge owners to take timely, proactive actions to mitigate or prevent further deterioration and unanticipated tendon failures. A detailed experimental study conducted to assess the performance of nondestructive evaluation techniques in detecting grout defects within internal tendons is presented herein. Nondestructive evaluation techniques that include Ground Penetrating Radar, Impact Echo, Ultrasonic Tomography, and Ultrasonic Echo are evaluated in terms of detecting the location and severity of fabricated grout defects in a full-scale post-tensioned U-girder mock-up specimen. While Ground Penetrating Radar can identify the location and profile of the internal tendons, particularly metal ducts due to strong reflections, this method did not provide any information about the defect conditions within the tendon. Both Impact Echo and Ultrasonic Echo techniques are effective in identifying the location of grout defects, but could not differentiate between water, void, or compromised grout conditions. The study clearly demonstrates the need for NDE techniques that are applicable to anchorage regions, and that are capable of estimating the severity and nature of grout defects in internal tendons.

The South Sumatra Basin is one most prolific hydrocarbon provinces in Indonesia (Figure 1) with estimated known petroleum resources of 4.3 billion barrels of oil equivalent (bboe) (Klett et al., 1997). Talang Akar Formation (TAF) is the main source and reservoir rock in the basin (Sarjono and Sardjito, 1989; Sosrowidjojo et al., 1994). It accounts for more than 75% of the cumulative oil production in the province and has approximately 2 bboe ultimate recoverable reserves (Tamtomo et al., 1997).

Applying ultrasonic-tomography systems makes it possible to precisely determine the shape and dimensions of flaws with the aim of establishing the degree to which the flaws influence safe operation of tested objects. This problem is solved by using special algorithms that make use of echo-signals recorded by an ultrasonic transducer to generate synthesized images of flaws in the sample. The use of phased arrays in ultrasonic tomography is explained by their ability to provide exhaustive data about the internal structure of a test object, thus allowing formation of the high-quality synthesized images of flaws in the object. Increasing the speed of ultrasonic tomography by using phased arrays necessitates the development and implementation of fast data-processing algorithms. In this connection, of interest are calculation algorithms in the frequency domain, which ensure the high speed of producing synthesized images. An ultrasonic-tomography algorithm is proposed that is based on calculations in the frequency domain. The algorithm takes the complex nature of the propagation of ultrasonic waves into account and is connected with the presence of media with different acoustic properties (e.g., in the case of immersion tests). Possibilities offered by the algorithm are investigated by computer simulations using the licensed CIVA 2016 software package and experimentally.

There is a growing need for nondestructively evaluate the integrity of trees and wooden structural elements. Such an investigation can be performed with the use of different test methods. Nevertheless, in order to yield acceptable results, the test methods should consider the anisotropic nature of the wood, which includes the shape of the annual rings, and also the pith location in the cross-section. This paper presents a new method to determine the pith location of a tree or structural element made of timber or lumber based on ultrasonic tomography readings.

In recent years, due to the destructive and unproductive character of pavement specimen extraction, pavement maintenance technology intensified the use of non-destructive techniques for pavement evaluation which resulted in the development of several devices and evaluation methods. This paper describes the use of technology based on low frequency ultrasonic tomography for evaluation of concrete pavement parameters. The equipment was applied in three experimental sections with different concrete pavements built at the University of Sao Paulo campus. The ultrasonic signal processing is given. The results analysis enables the efficient and reliable identification of thickness and reinforcement position within the concrete slab. Construction problems were evidenced in one of experimental sections with thickness deficiencies and reinforcement in a position below projected. Furthermore, the use of a novel concrete quality indicator was correlated with the presence of transverse cracks and alkali-silica reaction within the sections.

Despite decades of research, the study into the application of ultrasonic sensors in process tomography continues to be a subject of significant scientific interest. In this paper, we present a contemporary review of ultrasonic tomography (UT) systems for the application of liquid–gas multiphase flow. The evolution of this topic over the years and an overview of the UT system, measurement strategies, data acquisition, and image reconstruction techniques are described.

In the process of creating digital images of concrete, wave propagation can be used to generate a suitable inner representation of this element, producing an ultrasonic tomography. Although tomography devices are efficient in generating images, they are high-cost and not very accessible. On the other hand, images obtained through ultrasound tests allow identifying the presence of flaws in different types of materials at lower costs. In ultrasonic tests, ultrasonic wave velocity paths are generated from different measurement points. Thus, in order to improve the data range, interpolation techniques can be used to estimate the acoustic velocity at the unmeasured test points, completing the image creation process. This work aims to evaluate the influence on the quality of the generated image of (1) the spatial resolution and (2) the number of measurement points in the ultrasonic test. Experiments were carried out using Inverse Distance Weighting interpolation technique and ultrasonic tomography on concrete beams with and without flaws. The resulting images indicated the importance of the appropriate choice of number and arrangement of measuring points in the ultrasonic test to properly detect internal flaws. In addition, we verify that a higher spatial resolution may also interfere in the identification of internal flaws in the image.

Ultrasonic testing of concrete by modern equipment has grown in importance in recent years in non-destructive testing. Measuring concrete cover thickness and estimating steel rebar position and diameter is main focus for assessment of existing reinforcement concrete facilities. Voids, entrained air and potential delamination are important to detect in order to evaluate the quality of the executed concrete members. This paper presents the latest two modern non-destructive techniques – ultrasonic tomography and electromagnetic pulse induction – suitable for testing reinforcement concrete members. The capabilities of these techniques for locating defects, reinforcement bars and determining their size in unilaterally accessible concrete members are described.

There have been reports of road bridges that deteriorated after their RC slabs had been repaired. The insufficient removal of damaged materials is said to be the cause of such post-repair deterioration. Consequently, there is a call for a survey method that can detect deteriorated materials of bridges with high accuracy. Towards the development of such a method, this report focuses on ultrasonic tomography, because it can detect damage to the RC slabs of road bridges over relatively large areas. We examined the applicability of ultrasonic tomography to a method of assessing the RC slab damage by a test that uses a full-scale RC slab specimen that had been deteriorated by repeated loading on a wheel-tracking test machine. The results show that ultrasonic tomography is well able to detect areas of punching shear damage but not areas of horizontal cracking whose causes include both punching shear and compressive stress.

Industrial Process Tomography possesses unique advantages in biphasic medium measurement and has received broad attention in the past decades. Aiming at the widely existed low contrast biphasic medium, this paper proposed a nonlinear Ultrasonic Transmission Tomography (UTT). Approach using continuous wave excitation. Considering the refraction effect at the biphasic interface, the reconstruction method with nonlinear forward problem and the improved Simultaneous Algebraic Reconstruction Technique (SART) is proposed with high reconstruction accuracy and reconstruction speed. The performance of the reconstruction is quantitatively compared with the state-of-art reconstruction algorithms, where the proposed method can reconstruct inclusions with their number, size and position clearly identified. Quantitatively, the average Relative Error (RE) is 0.4835 using the proposed method, which is reduced by 49.34% and 40.57% compared with FBP and SART separately. Under parallel computation, the computing time of the proposed method reduced 16.56 times compared with the existing bent-ray tracing method. The proposed image reconstruction algorithm is proved to be an effective and improved approach to the liquid-liquid two-phase flow ultrasonic tomography.

This paper presents the development of an ultrasonic tomography system for multiphase flow imaging. Ultrasonic tomography (UT) modality has a hard-field sensing principle which makes feasible to measure liquid-gas, liquid-liquid and liquid-solid flow composition within a pipe vessel. The sensor configuration for the UT system is discussed along with its signal conditioning circuitry and image reconstruction technique. The feasibility of the system is experimentally carried out on a 100 mm acrylic pipe for a stratified multiphase flow measurement to reconstruct tomographic images.

The defect of the aluminum plate concerned in this chapter is mainly the plate thickness loss-type defect caused by corrosion, and the plate thickness change caused by such defects is relatively flat. When Lamb waves encounter such defects, the amplitudes of other modal waves generated by modal transformation are relatively small. Therefore, the effects caused by the modal transformation of Lamb waves are ignored in the following studies.

The problem of image reconstruction in ultrasonic tomography (UST) consists in both performing measurements using a set of sensors and creating of reconstruction based on these measurements. The image reconstruction requires accurate modeling of area, which presents field of view. To determine the inclusion in analyzed area the logistic regression has been applied. Additionally to select the predictors in logistic regression the elasticnet method has been used.

Computerized ultrasonic tomography is an important radiological technique because of its non-ionizing properties. However, it has been the subject of several studies due to the complexity of its visualization. In this work, a Ram-Lak filter is implemented in the Radon domain to reduce the noise levels in the images and facilitate their observation. Results obtained were superior to those reported in the state of the art with an average improvement of 8.1512 dB.

In this paper, an ultrasonic tomography method based on acoustic multi-parameter full waveform inversion (FWI) is developed for high-resolution reconstructions of velocity and density in metal components. The challenging issue in multi-parameter FWI is to deal with the trade-off effects between different parameters of different natures. Moreover, different parameters have different orders of amplitudes in the wave-field which make the inversion ill-conditioned. The inverse Hessian has been shown to mitigate the coupling effects and rescale the amplitudes of different parameters, and then the reliable updates of different parameters are available. The simultaneous reconstructions of velocity and density by using the truncated Gauss–Newton method, in which the inverse Hessian can be considered through a matrix-free conjugate gradient solution of the Gauss–Newton normal equation, are investigated by simulation as well as experiment on the centred inclusions. The results show that this method can effectively alleviate the trade-off effects between velocity and density, and thus the velocity of the inclusion is accurately reconstructed and the reconstruction of the density is well achieved.

Passive ultrasonic tomography is described. Results of developing, modeling, and testing some key techniques in passive ultrasonic tomography are provided. The techniques include an algorithm for determining arrival times of noisy acoustic signals with sloping leading edge; a method for determining the source coordinates and onset times of acoustic signals and estimating the accuracy of those; and regularizing procedures for tomographic reconstruction of nonuniform distributions of propagation speed of acoustic signals. The results of modeling the effect of measurement noises on the accuracy of source location and the mutual influence of the source location accuracy and the soughtfor nonuniform distribution of propagation speed of acoustic signals are described. Results of experimental testing of the developed techniques are also provided.

In this paper we evaluated a single plane ultrasonic tomography sensor and performed some experimentation to reconstruct three-dimensional profiles in a chemical bubble column. An array of 32 ultrasonic sensors was constructed and clamped on the exterior circumference of the column. The information of the profiles was captured based on time-of-flight and arrival-time analysis. Several phantom profiles were created and sampled using ultrasonic tomography techniques and the results were compared with high-speed camera images. The findings showed promising results where the reconstructed three-dimensional profiles matches with the high-speed camera images.

PurposeThe purpose of this paper is to conduct a review of types of tomographic systems that have been widely researched within the past 10 years. Decades of research on non-invasively and non-intrusively visualizing and monitoring gas-liquid multi-phase flow in process plants in making sure that the industrial system has high quality control. Process tomography is a developing measurement technology for industrial flow visualization.Design/methodology/approachA review of types of tomographic systems that have been widely researched especially in the application of gas-liquid flow within the past 10 years was conducted. The sensor system operating fundamentals and assessment of each tomography technology are discussed and explained in detail.FindingsPotential future research on gas-liquid flow in a conducting vessel using ultrasonic tomography sensor system is addressed.Originality/valueThe authors would like to undertake that the above-mentioned manuscript is original, has not been published elsewhere, accepted for publication elsewhere or under editorial review for publication elsewhere and that my Institute’s Universiti Teknologi Malaysia representative is fully aware of this submission.

The possibility of making ultrasonic 3D tomographs for medical diagnostics of soft tissues was established. The choice of frequencies of ultrasonic pulses of 300–500 kHz was due to low absorption in soft tissues within this range. The reverse problems of ultrasonic tomography, which are three-dimensional and nonlinear, have been considered in a model that takes into account both wave effects and absorption. The effectiveness of algorithms to solve the reverse problems that were developed has been illustrated by model calculations. The velocity configuration has been shown to be recovered better than the function that describes absorption in soft tissues.

A method of measurement of the velocity of ultrasonic vibrations in structural units made of concrete by means of ultrasonic phased antenna arrays without the use of samples is described. In the methods signals are processed by means of a plane focusing algorithm designed for the detection of reflecting planes. Results of measurements of the velocity of ultrasound in concrete are presented.

Industrial ultrasonic tomography (UT) possesses a unique advantage in gas–liquid two-phase distribution measurement and has received broad attention over the past decades. Focusing on a liquid-dominated gas-inclusion distribution reconstruction, we propose the strategy of multi-frequency fusion UT (MFFUT), which comprehensively models the transmission attenuation and self-adaptive fusion of multi-frequency reconstruction images through processing the measurement data with a frequency-dependent forward model and a metric-weighted fusion algorithm. Significant improvements to edge/shape preservation and artifact suppression are observed in both simulative and experimental reconstruction results. Quantitatively, the proposed strategy has a lower relative error and a higher correlation coefficient than any single frequency reconstruction method within all major categories of the reconstruction algorithm and under all inclusion complexities. Accordingly, the MFFUT strategy is proved to provide more accurate gas bubble distribution measurement in industrial processes.

This paper concerns inspection of reinforced concrete elements, with particular emphasis on assessing the quality of the adhesive connection between steel and concrete. A novel theoretical model was developed to determine the paths of transmitted, refracted and reflected elastic waves as well as a creeping wave propagated along the inclusion surface. Imaging the internal structure of tested beams was based on wave propagation measurements carried out on their surface and computed tomography. The ray tracing was performed by the hybrid approach as a combination of the network theory and the ray bending methods. The obtained results indicated a great potential of ultrasonic tomography in detection of debonding in reinforced concrete structures.

With the increasing use of preplaced aggregate concrete in construction, the grout filling in preplaced aggregate concrete is important for ensuring proper consolidation and high mechanical performance. This paper proposes a framework for determining the injectable grout fluidity for preplaced aggregate concrete according to the rheological properties of the grout mixture, which are associated with the filling performance for the given aggregates. To assess the grout filling, cost-effective, nondestructive ultrasonic pulse velocity (UPV) testing was performed, and ultrasonic tomography images were constructed for visually identifying internal air voids, which were verified by high-resolution micro-computed tomography. Rheometer tests evaluated the rheological properties of the grout mixtures. The UPV-based void-detection results and grout rheological properties were employed to determine the injectable grout fluidity range.

Oil-water biphasic medium widely existed in mining and transportation process of petroleum industry, where visualized measurement processes vital importance in production increase, state monitoring and fault prognosis. Ultrasonic Tomography (UT) is a non-invasive and non-radioactive sensing modality in industrial Process Tomography, which is demonstrated as a competitive monitoring technique with great potential. However, facing the refraction effect of Ultrasound wave at oil-water interfaces, the accuracy of reconstruction algorithm is with large error and serious artifacts. To address the issue, a modified ray-tracing image reconstruction algorithm is proposed. The amplitude attenuation during ultrasound propagation in nonhomogeneous medium is quantitatively modeled to form absolute UT model. With ray tracing strategy applied and improved, the nonlinear refraction effect is characterized in the form of iterative update of sensitivity matrix, followed by which the sound speed mapping transfers reconstructed attenuation images to sound speed distribution for ray tracing computation. Numerical tests indicate that the proposed method significantly improves reconstruction accuracy through projection-based, regularization-based and algebraic-based inverse algorithms, which demonstrate its benefits in conducting oil-water biphasic medium imaging.

В работе изучен спектр патологических процессов, являющихся источником аномальных маточных кровотечений в перии постменопаузе. Информативность сонографии в группе пациенток перименопаузального периода невысока – 57,9%. Продемонстрирована высокая эффективность ультразвуковой томографии у пациенток с маточными кровотечения в постменопаузальном возрасте. При информативности 86,0% точность, чувствительность и специфичность соответственно составляют 93,0; 93,8; 91,9%. Разработаны принципы первичной диагностики у пациенток с аномальным маточным кровотечением в перии постменопаузе. При убедительных данных первичной диагностики в отношении рака эндометрия необходимо использовать только аспирационную биопсию, исключая эндоскопическое обследование., In the article spectrum of pathological processes that can cause abnormal uterine bleeding during periand postmenopause is studied. Sonography informativeness in group of perimenopausal patients was low – 57.9%. High efficiency of ultrasonic tomography in postmenopausal patients with uterine bleeding has been demonstrated. When informative was 86.0%, accuracy, sensitivity and specificity were 93.0; 93.8; 91.9% respectively. Principles of primary diagnostics in patients with abnormal uterine bleeding in peri-and postmenopause have been developed. In case of convincing evidences of primary diagnostics in relation to endometrial cancer existence, only aspiration biopsy should be used, excluding endoscopic examination.

Nonlinear tomographic ultrasound reconstructions can provide quantitative data about material parameters like the speed of sound also in reflection-mode imaging. However, these methods suffer from the cycle skipping issue which is caused by the high center frequencies usual in medical ultrasound hardware. As these algorithms are based on minimization of a misfit function where the high frequency signals lead to local minima, false reconstruction are the result. Previous approaches try to circumvent this problem by low pass filtering the measured signals. This method is limited by the bandwidth and SNR of the measurement system. In this contribution, we applied the optimal transport distance known from seismic reconstructions. This approach uses all frequency components while enhancing the included traveltime information. We compare the misfit functions and show reconstructions using the standard and the optimal transport method. The results demonstrate an at least 1.6 times higher convergence limit.

The need for flow measurements throughout the production cycle has led to the development of a variety of multiphase flow meters. An ultrasonic tomographic multiphase flow meter is being developed in which it can potentially replace radioactive and invasive types of multiphase flow meters. The meter is configured to generate cross-sectional images of the flow inside the pipe in a non-invasive manner yet with direct contact to the fluid. Image reconstruction is generally carried out via inversion which requires a high level of computation complexity and processing time. It can be further challenged by the limited amount of data available. Compressed Sensing (CS) optimizes the conventional structure for data acquisition and compression. CS is based upon recovering certain data from very few measurements. Loosely speaking, most CS algorithms fall into either two categories; convex optimization recovery and greedy pursuits. In this paper, CS greedy pursuit algorithms are used to reconstruct sound speed images to find the most suitable algorithm in terms of image quality. Specifically, we made a comparative analysis of three greedy CS algorithms; Orthogonal Matching Pursuit (OMP), Compressive Sampling Matching Pursuit (CoSaMP), and Fast Bayesian Matching Pursuit (FBMP). We further compare the CS greedy reconstruction results to a conventional approach for image recovery based on the least-squares problem. Simulation results show that CS algorithms highly outperform the conventional approach for image recovery. Results demonstrate that high quality image recovery can be achieved using these simple greedy pursuit algorithms, sometimes even at increased system efficiency. Out of the three greedy algorithms, CoSaMP shows the highest quality for image recovery. Results also suggest that careful selection of the number of measurements used for recovery is necessary to obtain an accurate image reconstruction. As presented in this paper, our purpose is to adapt a CS approach, specifically greedy pursuit algorithms, for an efficient and an improved reconstruction of images generated by the ultrasonic tomographic multiphase flow meter to accurately quantify phase fractions in producing oil wells.

The authors are trying to develop an ultrasonic CT technique for concrete structures. As the first step of its development, we study how the ultrasonic waves propagate in concrete structures and pose a problem to develop ultrasonic CT, applying which we give a non-destructive inspection technique for concrete cover by application of the idea of the ultrasonic CT. The authors claim that this study gives the foundation of the theory of ultrasonic CT for concrete structures.