Non-destructive Measurement Research Articles

Fast Cable-Force Measurement for Large-Span Cable-Stayed Bridges Based on the Alignment Recognition Method and Smartphone-Captured Video

The accurate measurement of cable force plays an important role in the structural form, structural behavior, and safety evaluation of large-span cable-stayed bridges. A fast cable-force estimation method is proposed based on the alignment recognition method and smartphone-captured video. This method can realize real-time, non-contact, and non-destructive force measurements. Videos of bridge cables were collected using a portable smartphone, and an alignment recognition method was employed to obtain the lateral displacement along the cable, followed by numerical differentiation of the lateral displacement of the cable to acquire the acceleration time history. Based on the fundamental dynamic equation of beam elements, a unified explicit formula for cable-force calculation considering service characteristics was established in the frequency method. Finally, the method was applied to the cable-force measurement during the operation and maintenance stage of the Gengcun Dou Bridge. The measured cable forces were compared with the values obtained from the on-site monitoring system. The results show that the proposed method can accurately identify the acceleration time history at different positions of the cable, and the corresponding frequency components are essentially consistent. The average relative deviation of the measured cable forces from the reference method is within 3%. The proposed cable-force measurement method is simple as regards equipment, convenient for operation, and high in efficiency, providing a new method for the measurement of cable forces in large-span cable-stayed bridges, which can offer reliable measured cable-force data for structural analysis during bridge operation and the maintenance stage.

Repeatability and Reproducibility of Pavement Density Profiling Systems

The work conducted in this study was designed to establish achievable testing tolerances for non-destructive pavement density measurements using Density Profiling Systems (DPSs). Nine and six sensors were used to determine the precision of repeatability and reproducibility in the laboratory and the field, respectively. A minimum of six sensors (considered in this study as independent laboratories) were needed to comply with the minimum number of participants required in the current ASTM standard practice (ASTM E691). The methodology included the development of laboratory precision evaluation with a total of nine sensors and two different mixtures (9.5 mm fine-graded mix, 19.0 mm coarse-graded mix) compacted at four density levels (97%, 94%, 91%, and 88% of Gmm). For the field portion of this study, pavement sections built at the National Center for Asphalt Technology (NCAT) Test Track in 2021 served as experimental variables. These sections were built with fine-graded asphalt mixtures and open-graded mixes as wearing courses. Additionally, the pavement sections included three underlying materials: new asphalt (binder layer), milled asphalt surface, and granular base, with thicknesses ranging from 3.8 to 13.9 cm. Density profile testing was conducted at two locations: within the mat (center of the lane) and along the joint. Computed precision statements regarding dielectric values within and between laboratories were about double for field results compared to laboratory results. However, when converted to density, the statements were significantly below the reported statements for Bulk Specific Gravity and Vacuum Sealing in the laboratory and Nuclear and Electromagnetic density gauges in the field.

Non-Destructive Measurement on Kwini Mango Fruit using Capacitive Sensing Technique at 250kHz to 2MHz for Ripeness Determination

This study aims to evaluate the characteristics and quality of Kwini mango fruit using non-destructive capacitive sensing methods. Unlike other fruits, identifying ripe Kwini mangoes can be challenging due to their green appearance and unfamiliar characteristics to consumers. Despite the growing interest in non-destructive fruit quality assessment techniques, there has not been significant prior exploration of capacitive sensing in the context of Kwini mangoes. Therefore, in this experiment, a parallel plate was used to measure the capacitance of Kwini mango fruit at frequencies ranging from 250 kHz to 2 MHz. Results showed that the moisture content and pH level decreased within 15 days of investigation. This technique was able to predict Kwini maturity with significant precision by applying the capacitance formula. Because of its high R2 value and sensitivity in linear regression, 500kHz was determined to be the most efficient operating frequency for Kwini mango fruits among the frequencies evaluated. In this experiment, the relationship between capacitance and Brix also yielded encouraging findings. The study also includes the development of a GUI application for determining the sweetness and maturity of Kwini mangoes. Overall, this research demonstrates the potential of capacitive sensing technology as a non-destructive approach to measuring Kwini mango fruit ripeness.

Effects of factors from practical workpieces on ultrasonic LCR method stress measurement

The non-destructive stress measurement method is the main trend in residual stress analysis. The ultrasonic method, which utilizes the acoustoelastic effect of the longitudinal critically refracted (LCR) wave, is one of the time-saving measurement techniques. During the practical stress measurement on a workpiece, various external factors may impact the transmission of acoustic waves and the resulting stress value. This study revealed and discussed the effects of four factors on the LCR wave: surface roughness of the examined material, temperature of the material, external mechanical vibration, and surface paint. The stress coefficient was determined by comparing the offset time of the acoustic wave with the stress measured by X-ray analyzer in the zero-stress specimens, which had undergone annealing and deep cryogenic treatment. The test results indicated that the surface roughness did not affect the transition time of the acoustic wave, but it did decrease the intensity of the signal. The increase in temperature and the transition time of the acoustic wave were in a linear relationship. Mechanical vibrations from the environment would not affect the transition time or signal intensity of the acoustic wave, whereas the application of surface paint increased the transition time. Although the effect of paint on the actual workpiece could not be easily modified during stress measurement, the ultrasonic method was still suitable for monitoring the stress of a specific position of the workpiece throughout its operational lifetime. The experiment data in this study were applied to measuring the residual stress of an aluminum ship component, and the result showed a good correspondence with X-ray stress analyzer results.

Structure-dependent residual stress of thermal barrier coating on turbine blade with exposure to high temperature

This work aims to investigate the structure-dependent residual stress of thermal barrier coating systems (TBCs) on actual turbine blades with curved surfaces, and explore the relationship between stress and failure in different blade regions. A specialized non-destructive stress measurement setup was developed for this purpose. The residual stresses in the top coat (TC) and thermally grown oxide (TGO) layer at different blade regions, namely the convex surface, the concave surface, and the leading-edge surface, were measured during isothermal oxidation services. A phenomenon of residual stress reversal was discovered. The structure-dependent failures of TBCs in different blade regions were found to be strongly correlated with the residual stress in the TGO layer, rather than the TC layer. These results significantly enhance our understanding of the failure mechanism and contribute to the prediction of service lifetimes for turbine blades equipped with TBCs.

Fast, Nondestructive and Precise Biomass Measurements Are Possible Using Lidar-Based Convex Hull and Voxelization Algorithms

Light detection and ranging (lidar) scanning tools are available that can make rapid digital estimations of biomass. Voxelization and convex hull are two algorithms used to calculate the volume of the scanned plant canopy, which is correlated with biomass, often the primary trait of interest. Voxelization splits the scans into regular-sized cubes, or voxels, whereas the convex hull algorithm creates a polygon mesh around the outermost points of the point cloud and calculates the volume within that mesh. In this study, digital estimates of biomass were correlated against hand-harvested biomass for field-grown corn, broom corn, and energy sorghum. Voxelization (r = 0.92) and convex hull (r = 0.95) both correlated well with plant dry biomass. Lidar data were also collected in a large breeding trial with nearly 900 genotypes of energy sorghum. In contrast to the manual harvest studies, digital biomass estimations correlated poorly with yield collected from a forage harvester for both voxel count (r = 0.32) and convex hull volume (r = 0.39). However, further analysis showed that the coefficient of variation (CV, a measure of variability) for harvester-based estimates of biomass was greater than the CV of the voxel and convex-hull-based biomass estimates, indicating that poor correlation was due to harvester imprecision, not digital estimations. Overall, results indicate that the lidar-based digital biomass estimates presented here are comparable or more precise than current approaches.

Rapid single flax (Linum usitatissimum) seed phenotyping of oil and other quality traits using single kernel near infrared spectroscopy

AbstractThe growing interest in the rapid measurement of seed ingredients using single‐kernel NIR (SKNIR) spectroscopy as a nondestructive measurement technique allows fast analysis of sample seed variance that can have effects on breeding and end‐use processing. Flax (Linum usitatissimum), an oilseed crop grown in the Northwest United States and worldwide, is highly beneficial for human health, food, and fiber. Its health benefits include its high protein and omega‐3 fatty acids content. Therefore, seed composition profiles are an important aspect of breeding. The goals of this research were the development of single seed NIR calibration models for protein, oil, and weight of intact flax seeds. In this study, SKNIR spectroscopy was used on a diverse set of flax accessions comprising of 306 samples to create prediction models on a custom built SKNIR instrument. Spectra data and reference protein, oil, and weight were used to build partial least squares (PLS) models. Calibration models provided reasonable prediction of these traits and could be used for screening purposes. PLS statistics were oil (R2 = 0.82, SEP = 1.72), weight (R2 = 0.74, SEP = 0.71), and protein (R2 = 0.62, SEP = 0.96) for validation data sets comprising of one‐third of the total samples. In conclusion, prediction models showed that SKNIR spectroscopy could be a very beneficial nondestructive technique to determine oil and weight as well as rapid screening of protein in single flax seeds while not requiring extensive preparation as compared to traditional techniques.

An Artificial Neural Network-Based Approach to Improve Non-Destructive Asphalt Pavement Density Measurement with an Electrical Density Gauge

Asphalt pavement density can be measured using either a destructive or a non-destructive method. The destructive method offers high measurement accuracy but causes damage to the pavement and is inefficient. In contrast, the non-destructive method is highly efficient without damaging the pavement, but its accuracy is not as good as that of the destructive method. Among the devices for non-destructive measurement, the nuclear density gauge (NDG) is the most accurate, but radiation in the device is a serious hazard. The electrical density gauge (EDG), while safer and more convenient to use, is affected by the factors other than density, such as temperature and moisture of the environment. To enhance its accuracy by minimizing or eliminating those non-density factors, an original approach based on artificial neural networks (ANNs) is proposed. Density readings, temperature, and moisture obtained by the EDG are the inputs, and the corresponding densities obtained by the NDG are the outputs to train the ANN models through Levenberg-Marquardt, Bayesian regularization, and Scaled Conjugate Gradient algorithms. Results indicate that the ANN models trained greatly improve the measurement accuracy of the electrical density gauge.

Ultrasonic pulse velocity as a non-destructive measure for the projectile impact resistance of cementitious composites across a wide range of mix compositions

This paper presents an investigation on the applicability of using ultrasonic pulse velocity (UPV) as a non-destructive measure for characterizing high velocity projectile impact (HVPI) resistance as well as physical/mechanical properties of cementitious composites across a wide range of mix compositions. Ultra-high performance concretes (UHPCs), engineered cementitious composites (ECCs), concretes, mortars and cement pastes with compressive strengths ranging from 34.2 MPa to 220.2 MPa and elastic moduli ranging from 17.1 GPa to 104.2 GPa are considered for investigation. Projectile impact resistance of cementitious composites is evaluated in terms of the depth of penetration (DOP) and equivalent crater diameter (ECD). Physical/mechanical properties, including compressive strength, static and dynamic moduli of elasticity, density, hardness, splitting tensile strength, compressive and flexural toughnesses, are investigated. The UPV is found to be a promising non-invasive and non-destructive measure for the DOP characterization, since both the UPV and DOP are governed by the weighted properties of underlying constituent materials (e.g. matrix and fine/coarse aggregate). In comparison to the DOP, the correlation between the ECD and UPV is relatively weak. The results indicate that there exists a strong correlation between the UPV and the elastic modulus/density/hardness of cementitious composites. It is also found that commonly used two-phase composite models can predict the UPV of concrete with good accuracy.

The utilization of wood samples from xylarium in historical wooden statues: improving the separation accuracy non-destructive measurement for using several algorithms

There are numerous wooden historical artifacts in Kyoto and other parts of Japan, including Buddhist statues or Shinto deities. The identification of wood species in these historical artifact is desirable for both repair and maintenance purposes. The most common method of identifying wood species involves examining samples taken from the artifacts. However, intentional sampling from old cultural artifacts is prohibited in Japan. As a result, we attempted to determine the wood species of old statues non-destructively using near-infrared spectroscopy (NIRS). In this article, we developed the softwood and hardwood separation model using NIRS to compare the prediction accuracy for few algorithms. The model was created based on wood samples stored in the xylarium of the Forestry and Forest Products Research Institute (TWTw). We then applied this model to old Buddhist statues in order to classify them as either softwood or hardwood. These Buddhist statues were housed in Nazenji temple and are believed to have been carved during the Heian period (8th–12th century). For the near-infrared (NIR) measurements, we collected diffuse reflectance spectra from TWTw sample and Buddhist statues using same spectrometer. Initially, we used the soft independent modeling of class analogy method (SIMCA), partial least squares discriminant analysis (PLS_DA), and support vector machine to analyze the NIR spectra obtained from the TWTw wood samples. Subsequently, we applied the NIR spectra obtained from several Buddhist statues in Nazenji temple to the aforementioned separation model and determined whether spectra data were classified as the softwood or hardwood. Finally, wood specimens detached naturally from the Buddhist statues over time were observed under microscopic analysis to identify the wood species. As comparing the prediction accuracy of few algorithms, SIMCA had a poor result, but PLS_DA had a good result. PLS_DA had better discrimination because it performed calculations to improve regression from both explanatory variables and objective variables.

High sensitivity temperature sensing material In2Li3P3O12: Bi3+, Eu3+ based on effective energy transfer from Bi3+ to Eu3+

In recent years, fluorescent temperature sensing materials have been widely studied because they can realize remote non-destructive temperature measurement. High temperature sensitivity and excellent temperature resolution are the eternal pursuit of fluorescence temperature sensing. Here, we report the preparation, structure, luminescent properties and temperature sensing performance of phosphor In2Li3P3O12: Bi3+, Eu3+. Eu3+ singly doped samples can emit red light under 270 nm excitation. There is effective energy transfer from Bi3+ to Eu3+ in the Bi3+ and Eu3+ co-doped samples. Doping Bi3+ on the basis of doping Eu3+ can significantly enhance the luminescence intensity of Eu3+ ions. Ultraviolet light from Bi3+ and red light from Eu3+ are chosen to design a fluorescence intensity ratio thermometer for more accurate temperature detection. The temperature sensing technology has a maximum absolute and relative sensitivity is up to 0.0087 K−1 at 298 K−1 and 2.71 % K−1 at 325 K, respectively. This has a higher sensitivity than many phosphors available on the market. This indicates that it is a kind of fluorescence temperature sensing material with great potential.

A High-Resolution Measurement Method for Inner and Outer 3D Surface Profiles of Laser Fusion Targets Using a Laser Differential Confocal–Atomic Force Probe Technique

The high-resolution and nondestructive co-reference measurement of the inner and outer three-dimensional (3D) surface profiles of laser fusion targets is difficult to achieve. In this study, we propose a laser differential confocal (LDC)–atomic force probe (AFP) method to measure the inner and outer 3D surface profiles of laser fusion targets at a high resolution. This method utilizes the LDC method to detect the deflection of the AFP and exploits the high spatial resolution of the AFP to enhance the spatial resolution of the outer profile measurement. Nondestructive and co-reference measurements of the inner profile of a target were achieved using the tomographic characteristics of the LDC method. Furthermore, by combining multiple repositionings of the target using a horizontal slewing shaft, the inner and outer 3D surface profiles of the target were obtained, along with a power spectrum assessment of the entire surface. The experimental results revealed that the respective axial and lateral resolutions of the outer profile measurement were 0.5 and 1.3 nm, while the respective axial and lateral resolutions of the inner profile measurement were 2.0 nm and approximately 400.0 nm. The repeatabilities of the root-mean-square deviation measurements for the outer and inner profiles of the target were 2.6 and 2.4 nm, respectively. We believe our study provides a promising method for the high-resolution and nondestructive co-reference measurement of the inner and outer 3D profiles of laser fusion targets.

Effects of mineralization on the hierarchical organization of collagen-a synchrotron X-ray scattering and polarized second harmonic generation study.

The process of mineralization fundamentally alters collagenous tissue biomechanics. While the structure and organization of mineral particles have been widely studied, the impact of mineralization on collagen matrix structure, particularly at the molecular scale, requires further investigation. In this study, synchrotron X-ray scattering (XRD) and polarization-resolved second harmonic generation microscopy (pSHG) were used to study normally mineralizing turkey leg tendon in tissue zones representing different stages of mineralization. XRD data demonstrated statistically significant differences in collagen D-period, intermolecular spacing, fibril and molecular dispersion and relative supramolecular twists between non-mineralizing, early mineralizing and late mineralizing zones. pSHG analysis of the same tendon zones showed the degree of collagen fibril organization was significantly greater in early and late mineralizing zones compared to non-mineralizing zones. The combination of XRD and pSHG data provide new insights into hierarchical collagen-mineral interactions, notably concerning possible cleavage of intra- or interfibrillar bonds, occlusion and reorganization of collagen by mineral with time. The complementary application of XRD and fast, label-free and non-destructive pSHG optical measurements presents a pathway for future investigations into the dynamics of molecular scale changes in collagen in the presence of increasing mineral deposition.

Research on Measuring the Bodies of Underwater Fish with Inclined Positions Using the YOLOv8 Model and a Line-Laser System

Fish body measurement is essential for monitoring fish farming and evaluating growth. Non-destructive underwater measurements play a significant role in aquaculture management. This study involved annotating images of fish in aquaculture settings and utilized a line laser for underwater distance calibration and fish body inclined-angle calculation. The YOLOv8 model was employed for fish identification and key-point detection, enabling the determination of actual body dimensions through a mathematical model. The results show a root-mean-square error of 6.8 pixels for underwater distance calibration using the line laser. The pre-training YOLOv8-n, with its lower parameter counts and higher MAP values, proved more effective for fish identification and key-point detection, considering speed and accuracy. Average body length measurements within 1.5 m of the camera showed a minor deviation of 2.46% compared to manual measurements. The average relative errors for body length and width were 2.46% and 5.11%, respectively, with corresponding average absolute errors. This study introduces innovative techniques for fish body measurement in aquaculture, promoting the digitization and informatization of aquaculture processes.

Development of a non-intercepting weak beam current measurement electronics for Heavy Ion Accelerator Facility in Lanzhou.

Non-destructive measurements of low-intensity charged particle beams are particularly challenging for beam diagnostics. At the Heavy Ion Accelerator Facility in Lanzhou (HIRFL), beams with weak currents below 1 µA are often provided for experiments. The detection of such low beam current is below the threshold of typical standard beam current transformers. Therefore, a low-intensity monitoring system is developed by using a sensitive capacitive pick-up (PU) and low-noise electronics. This device measures beam currents by digitally analyzing the amplitude of the PU signals using a homodyne detection scheme. During lab tests, the amplitude nonlinearity is <0.5% in the operational range of 1 nA-45 µA and the amplitude resolution is 0.94 nA. At present, four measurement systems for low beam currents are installed at HIRFL for the monitoring of standard operating conditions with low beam currents below 1 µA. After an absolute calibration with a Faraday cup, it can be used for accurate beam intensity measurement with a current resolution of about 1 nA.

Characterization and verification of low-enriched uranium plate using a non-destructive methodology

Non-destructive methods play a crucial role in evaluating the integrity of nuclear materials. During the production of low-enriched mini-uranium plates, some destructive tests were initially employed to assess parameters such as uranium meat density, homogeneity, 235U enrichment, and meat distribution within the clad. While these destructive methods provide precise measurements during the manufacturing process, they become impractical and costly post-fabrication. Consequently, non-destructive tests are employed for quality control, verification, and inspection of nuclear materials. Laboratories and factories are developing non-destructive methods that yield results closely aligned with destructive measurements. The present research focuses on creating non-destructive measurements for verifying 235U enrichment and meat distribution in mini-uranium plates. This innovative approach involves utilizing 235U gamma emission as input to calculate enrichment and meat distribution. High purity germanium (HPGe) and sodium iodide (NaI) detectors alongside MCNPX code for efficiency correction were used in the proposed non-destructive measurements, respectively. The obtained results were validated and verified against certified measurements and x-ray images of mini-uranium plate. The enrichment measurement exhibited consistency with certified measurements, with about 0.8% difference. Similarly, the meat distribution measurement aligned with the x-ray image of the plate. This research proposes a practical application for nuclear material control during mini-uranium plate fabrication and for ensuring accountability and verification of inventory in storage facilities.

UltraMARS system for non-destructive measurement of residual stresses: New developments

UltraMARS system for non-destructive measurement of residual stresses: New developments

Discussion of “Nondestructive measurement of the capillary water absorption coefficient and water transport behaviors of porous building materials by using single-sided NMR”

In February 2024, Construction and Building Materials published the paper “Nondestructive measurement of the capillary water absorption coefficient and water transport behaviors of porous building materials by using single-sided NMR”, which claims to measure the capillary absorption of moisture in brick, sandstone, mortar and concrete by means of moisture content profiling with the ‘NMR mouse’, a low-field, single-sided, open-magnet NMR instrument. This critique formulates several serious concerns on the study’s outcomes and conclusions. The excessively large similarity of the capillary absorption behaviour of the four materials is peculiar, since it disregards the differences in their open porosities and pore sizes. The overly large capillary moisture contents are equally abnormal, as they exceed the moisture storage limit of the material’s pore structure. There appears to be an inconsistency between the moisture content profiles and the overall moisture masses. Finally, it is shown that the lengthy time interval necessary for a single NMR pass limits the applicability of the NMR mouse for capillary absorption coefficients of porous building materials.

NMR in Battery Anode Slurries with a V-Shaped Sensor.

Inline analytics in industrial processes reduce operating costs and production rejection. Dedicated sensors enable inline process monitoring and control tailored to the application of interest. Nuclear Magnetic Resonance is a well-known analytical technique but needs adapting for low-cost, reliable and robust process monitoring. A V-shaped low-field NMR sensor was developed for inline process monitoring and allows non-destructive and non-invasive measurements of materials, for example in a pipe. In this paper, the industrial application is specifically devoted to the quality control of anode slurries in battery production. The characterization of anode slurries was performed with the sensor to determine chemical composition and detect gas inclusions. Additionally, flow properties play an important role in continuous production processes. Therefore, the in- and outflow effects were investigated with the V-shaped NMR sensor as a basis for the future determination of slurry flow fields.

Wide-range resistivity characterization of semiconductors with terahertz time-domain spectroscopy

Resistivity is one of the most important characteristics in the semiconductor industry. The most common way to measure resistivity is the four-point probe method, which requires physical contact with the material under test. Terahertz time domain spectroscopy, a fast and non-destructive measurement method, is already well established in the characterization of dielectrics. In this work, we demonstrate the potential of two Drude model-based approaches to extract resistivity values from terahertz time-domain spectroscopy measurements of silicon in a wide range from about 10−3 Ωcm to 102 Ωcm. One method is an analytical approach and the other is an optimization approach. Four-point probe measurements are used as a reference. In addition, the spatial resistivity distribution is imaged by X-Y scanning of the samples to detect inhomogeneities in the doping distribution.