Pulsed Eddy Current Non-destructive Testing and Evaluation:A Review

Pulsed eddy current （PEC） non-destructive test- ing and evaluation （NDT＆E） has been around for some time and it is still attracting extensive attention from researchers around the globe, which can be witnessed through the reports reviewed in this paper. Thanks to its richness of spectral components, various applications of this technique have been proposed and reported in the lit- erature covering both structural integrity inspection and material characterization in various industrial sectors. To support its development and for better understanding of the phenomena around the transient induced eddy currents, attempts for its modelling both analytically and numeri- cally have been made by researchers around the world. This review is an attempt to capture the state-of-the-art development and applications of PEC, especially in the last 15 years and it is not intended to be exhaustive. Future challenges and opportunities for PEC NDT＆E are also presented.

Optical generation,detection and non-destructive testing applications of terahertz waves

Optoelectronic terahertz generation and detection play a key role in the applications of non-destructive testing,which involves different areas such as physics,biological,material science,imaging,explosions detection,astronomy applications,semiconductor technology and superconductiong electronics. In this article,we present a reviewof the principle and performance of typical terahertz sources,detectors and non-destructive testing applications. On this basis,the newdevelopment and trends of terahertz radiation detectors are also discussed.

Non-destructive experimental testing and modeling of electrical impedance behavior of untreated and treated ultra-soft clayey soils

The characterization of ultra-soft clayey soil exhibits extreme challenges due to low shear strength of such material.Hence,inspecting the non-destructive electrical impedance behavior of untreated and treated ultra-soft clayey soils gains more attention.Both shear strength and electrical impedance were measured experimentally for both untreated and treated ultra-soft clayey soils.The shear strength of untreated ultra-soft clayey soil reached 0.17 kPa for 10% bentonite content,while the shear strengths increased to 0.27 kPa and 6.7 kPa for 10% bentonite content treated with 2% lime and 10% polymer,respectively.The electrical impedance of the ultra-soft clayey soil has shown a significant decrease from 1.6 kΩ to 0.607 kΩ when the bentonite content increased from 2% to 10% at a frequency of 300 kHz.The10%lime and 10% polymer treatments have decreased the electrical impedances of ultra-soft clayey soil with 10%bentonite from 0.607 kΩ to 0.12 kΩ and 0.176 kΩ,respectively,at a frequency of 300 kHz.A new mathematical model has been accordingly proposed to model the non-destructive electrical impedancefrequency relationship for both untreated and treated ultra-soft clayey soils.The new model has shown a good agreement with experimental data with coefficient of determination（R;）up to 0.99 and root mean square error（RMSE） of 0.007 kΩ.

Application Research of the Non-Destructive Testing Using Optical Fiber Sensor

In this paper, an optical fiber sensor is designed by using optical Faraday effect. It is composed of fiber collimator, polarizer, magneto-optical crystal and mirror. Based on the magnetic flux leakage (MFL) theory, The optical fiber sensor was placed between two permanent magnets with the N-pole. Therefore, the optical fiber sensing system was built to detect the defective ferromagnetic objects. Theoretical and experimental studies shown that the system can identify a little defects, such as irons’ blind hole (diameter φ =?3mm , depth t = 4mm?), irons’ grooves (length l= 30mm , width?ω = 10mm ), hole (φ?=?3mm ) and crackle etc. The system has the characteristics of small size, high sensitivity, fast signal response and high resolution. In terms of the defective oil and gas pipelines detection, The optical fiber sensing system is used in non-destructive testing, which will be valuable and meaningful.

Non-Destructive Testing of Rods Using a Potential Component of a Magnetic Field

An essentially new method for non-destructive testing of elastic electrically conductive rods using non-vortex electromagnetic induction is proved theoretically. An experimental technique for defining a location of a cross crack is offered.

Non-destructive Evaluation of Absolute Stress in Steel Members Using Shear-Wave Spectroscopy

Non-destructive measurement of absolute stress in steel members can provide useful information to optimize the design of steel structures and allow the safety of existing structures to be evaluated.This paper investigates the non-destructive capability of ultrasonic shear-wave spectroscopy in absolute stress evaluation of steel members.The effect of steel-member stress on the shear-wave amplitude spectrum is investigated,and a method of absolute stress measurement is proposed.Specifically,the process for evaluating absolute stress using shear-wave spectroscopy is summarized.Two steel members are employed to investigate the relationship between the stress and the frequency in shear-wave echo amplitude spectrum.The H-beam loaded by the universal testing machine is evaluated by the proposed method and the traditional strain gauge method for verification.The results show that the proposed method is effective and accurate for determining absolute stress in steel members.

Biomarker Testing Rates in Patients with Advanced Non-Small Cell Lung Cancer Treated in the Community

Introduction: Over the past few years, molecular targeted therapies have been?emerging for the treatment of metastatic non-small cell lung cancer (NSCLC).?Targeted therapy is associated with improved outcomes in patients with identified gene alterations, and national guidelines recommend routine biomarker testing. This study evaluated real-world rates of documented epidermal growth factor receptor (EGFR) mutation and other biomarker testing in patients with advanced NSCLC over time.?Methods: Adult patients with Stage IV NSCLC were identified between January 1, 2012 and May 31, 2017 from the US Oncology Network iKnowMedTM?electronic health records. Patients were examined overall and by histology. Rates of documented EGFR mutation and other biomarker testing were calculated. Multivariable regression analyses were conducted to identify characteristics associated with documented biomarker testing. Results: A total of 14,461 patients were identified: median age was 69.3 years, 52.3% were male, 14.6% were nonsmokers, and 64.7% had non-squamous histology.?EGFR mutation testing rates were 35.5%?overall, with an increase in rates seen over time: 30.0% in 2012 to 44.0% in 2016?(p??0.001).?Anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1), and programmed death-ligand 1 (PD-L1) mutation testing rates were 32.9%, 5.7%, and 5.7%, respectively. More recent diagnosis year, non-squamous histology, larger practice size, and nonsmoking status were strongly associated with higher documented EGFR and ALK mutation testing rates.?Conclusions: EGFR mutation testing rates steadily increased over time, but remained less than 50%, with lower mutation testing rates reported for ALK, ROS1, and PD-L1, suggesting that opportunities exist to improve education on testing for biomarkers in NSCLC.

Non-Destructive Imaging of Water Permeation through Cementitious Materials Using MRI

In this study, water permeation through cementitious materials was observed using magnetic resonance imaging (MRI). The influence of cement type on the magnetic resonance signal was studied subsequent to determining the parameters required for imaging. Consequently, adequate imaging of water permeating through hardened cement paste (HCP) made with white Portland cement was achieved, while water permeation through ordinary Portland cement-based HCP yielded poor signal. HCPs maintained at various levels of relative humidity (RH) were observed, and the signal was detected only from those maintained at an RH of higher than 85%. The water permeation depths in HCP were observed by using MRI, and the measured depths were compared to those measured via a spraying water detector on the split surface of the specimens. As a result, good agreement was confirmed between the two methods. Additionally, MRI was applied to concrete specimens;although it was found that water was not detected when a lightweight aggregate was used, water permeation through concrete with limestone aggregate was detectable via MRI. MRI will help in understanding how water permeation causes and accelerates concrete deteriorations such as rebar corrosion and freezing and thawing.

Comparison of Type I Error Rates of Siegel-Tukey and Savage Tests among Non-Parametric Tests

This study aimed to examine the performance of the Siegel-Tukey and Savage tests on data sets with heterogeneous variances. The analysis, considering Normal, Platykurtic, and Skewed distributions and a standard deviation ratio of 1, was conducted for both small and large sample sizes. For small sample sizes, two main categories were established: equal and different sample sizes. Analyses were performed using Monte Carlo simulations with 20,000 repetitions for each scenario, and the simulations were evaluated using SAS software. For small sample sizes, the I. type error rate of the Siegel-Tukey test generally ranged from 0.045 to 0.055, while the I. type error rate of the Savage test was observed to range from 0.016 to 0.041. Similar trends were observed for Platykurtic and Skewed distributions. In scenarios with different sample sizes, the Savage test generally exhibited lower I. type error rates. For large sample sizes, two main categories were established: equal and different sample sizes. For large sample sizes, the I. type error rate of the Siegel-Tukey test ranged from 0.047 to 0.052, while the I. type error rate of the Savage test ranged from 0.043 to 0.051. In cases of equal sample sizes, both tests generally had lower error rates, with the Savage test providing more consistent results for large sample sizes. In conclusion, it was determined that the Savage test provides lower I. type error rates for small sample sizes and that both tests have similar error rates for large sample sizes. These findings suggest that the Savage test could be a more reliable option when analyzing variance differences.

NON-DESTRUCTIVE PAVEMENT LAYER THICKNESS MEASUREMENT USING EMPIRICAL MODE DECOMPOSITION WITH GPR

Ground Penetrating Radar(GPR) is an effective Non-Destructive Testing(NDT) technique for highway pavement surveys, which is able to acquire continuous pavement data compared with traditional core drilling method. In this study, we proposed an accurate and efficient method to estimate the thickness of each pavement layer using an air-coupled GPR system. For this work, the main difficulties are estimating each pavement layer's time delay and dielectric constant. We first give the basic signal model for pavement evaluation, and then present an Intrinsic Mode Functions(IMFs) product detector to determine each pavement layer's time delay. This method is based on Empirical Mode Decomposition(EMD), which is an adaptive signal decomposition procedure and proved to be suitable for suppressing noises in GPR signal. The dielectric constant was determined by metal reflection measurement. The laboratory and highway experiments illustrate that the proposed thickness estimation method yields reasonable result, thus meets the requirements of practical highway pavement survey with massive GPR data.

Non-destructive study of fruits using grating-based X-ray imaging

Grating-based X-ray imaging can make use of conventional tube sources to provide absorption, refraction and scattering contrast images from a single set of projection images efficiently. In this paper, a fresh cherry tomato and a dried umeboshi are imaged by using X-ray Talbot–Lau interferometer. The seed distribution in the scattering image of the cherry tomato, and the wrinkles of epicarp in the refraction image of the umeboshi, are shown distinctly. The refraction and scattering images provide more information on subtle features than the absorption image. Also, the contrast-to-noise ratio values show distinguishing capacity of the three kinds of imaging techniques. The results confirm that grating-based X-ray imaging is of great potential in non-destructive fruit testing.

Determination of Bonding Failures in Transparent Materials with Non-Destructive Methods—Evaluation of Climatically Stressed Glued and Laminated Glass Compounds

As part of an international research project—funded by the European Union—capillary glasses for facades are being developed exploiting storage energy by means of fluids flowing through the capillaries. To meet highest visual demands, acrylate adhesives and EVA films are tested as possible bonding materials for the glass setup. Especially non-destructive methods (visual analysis, analysis of birefringent properties and computed tomographic data) are applied to evaluate failure patterns as well as the long-term behavior considering climatic influences. The experimental investigations are presented after different loading periods, providing information of failure developments. In addition, detailed information and scientific findings on the application of computed tomographic analyses are presented.

The Research Progress of Nondestructive Testing Technology in the Detection of Egg Quality

[Objective]The aim was to improve the quality of the egg in favour of producers and business operators according to the market demand to take scientific feeding and management.[Methods]This paper discussed the research progress of using machine vision,optical properties,and acoustic resonance technology in the egg quality nondestructive testing. [Results]Egg quality indicators directly affect their edible quality and quality levels. [Conclusion]Egg quality test has practical value and practical significance.

Nondestructive Testing Electrical Methods for Sensing Damages in Cement Mortar Beams

This paper discusses the experimental results of concurrently measured Electrical and Acoustic Emissions in order to evaluate the mechanical health status of cement mortar beams subjected to three-point bending mechanical tests. In particular, the Electrical Resistance and the Electrical Current emissions are recorded concurrent with Acoustic Emissions and the experimental results are discussed under the concept of crack initiation and propagation processes. For the first time, the electrodes that are used for conducting the measurements are placed in the bulk of the specimen, near the tensile zone, during its preparation. The damage evolution is examined by monitoring the fractional change of the Electrical Resistance and the variation of the Electrical Current in combination with the Acoustic Emission recordings.

Comparison of next generation sequencing-based and methylated DNA immunoprecipitation-based approaches for fetal aneuploidy non-invasive prenatal testing

Over the past few years, many researchers have attempted to develop non-invasive prenatal testing methods in order to investigate the genetic status of the fetus. The aim is to avoid invasive procedures such as chorionic villus and amniotic fluid sampling, which result in a significant risk for pregnancy loss. The discovery of cell free fetal DNA circulating in the maternal blood has great potential for the development of non-invasive prenatal testing(NIPT) methodologies. Such strategies have been successfully applied for the determination of the fetal rhesus status and inherited monogenic disease but the field of fetal aneuploidy investigation seems to be more challenging. The main reason for this is that the maternal cell free DNA in the mother's plasma is far more abundant, and because it is identical to half of the corresponding fetal DNA. Approaches developed are mainly based on next generation sequencing(NGS) technologies and epigenetic genetic modifications, such as fetal-maternal DNA differential methylation. At present, genetic services for non-invasive fetal aneuploidy detection are offered using NGS-based approaches but, for reasons that are presented herein, they still serve as screening tests which are not readily accessed by the majority of couples. Here we discuss the limitations of both strategies for NIPT and the future potential of the methods developed.

Assessment of Oral English: Testing the Non-English Major Students at Guangxi TCM University in P.R. China

This paper intends to give a brief overview of oral English testing for non-English major students in Guangxi Traditional Chinese Medical (TCM) University, which is located in a minority autonomous province in the southern part of P.R. China. It arises from the concrete problems facing Chinese teachers of English who feel troubled when offering an oral English test to an ever increasing number of non-English major students at the end of each semester. The frustration comes not only from the labor intensive and time consuming activity but also from the surrounding ethical issues of subjectivity by the teachers and of injustice to the students to give and receive fair marks. Moreover, there is a conflicting gap between the criteria used by the foreign native English speaking teachers and Chinese teachers of English because of their different cultural background and concept of testing. Nevertheless, an oral English test was designed and the procedures were devised, adopted, and administered to assess the student’s performance. The test and procedures, based on the national course syllabus for testing non-English majors, the level of attainment in oral English of the students, and the limited number of teaching personnel in the TCM University, utilized two different approaches. The native English speakers follow their own concept of devising formats of group testing procedures and assessment criteria forms highlighting communicative interaction. Meanwhile, the Chinese teachers of English emphasize individual rehearsed presentations and ask the student to follow up questions, to make further comment, and inquire about learning experience from the passage in order to make assessment and evaluation. Final student scores were calculated by combining daily participation of the student, the assessment foreign teacher, and the evaluation of Chinese teachers.

Optimal Design of Multiple Stress Constant Accelerated Life Test Plan on Non-rectangle Test Region

For optimal design of constant stress accelerated life test（CSALT） with two-stress, if the stresses could not reach the highest levels simultaneously, the test region becomes non-rectangular. For optimal CSALT design on non-rectangle test region, the present method is only focused on non-rectangle test region with simple boundary, and the optimization algorithm is based on experience which can not ensure to obtain the optimal plan. In this paper, considering the linear-extreme value model and the optimization goal to minimize the variance of lifetime estimate under normal stress, the optimal design method of two-stress type-I censored CSALT plan on general non-rectangular test region is proposed. First, two properties of optimal test plans are proved and the relationship of all the optimal test plans is determined analytically. Then, on the basis of the two properties, the optimal problem is simplified and the optimal design method of two-stress CSALT plan on general non-rectangular test region is proposed. Finally, a numerical example is used to illustrate the feasibility and effectiveness of the method, The result shows that the proposed method could obtain the optimal test plan on non-rectangular test regions with arbitrary boundaries. This research provides the theory and method for two-stress optimal CSALT planning on non-rectangular test regions.

Macrosomia in non-gestational diabetes pregnancy:glucose tolerance test characteristics and feto-maternal complications in tropical Asia Pacific Australia

Objective:To look into the glucose tolerance test characteristics and determine complications in non-gestational diabetes pregnant subjects.Methods:From 2006 to 2009 all non-gestational diabetes mellitus(non-CDM)pregnant women who delivered macrosomia at the North Australia's Townsville Hospital were retrospectively reviewed by extracting data from clinical record.Glucose tolerance tests results were analysed in the light of an earlier diagnosis of non-GDM.Results:Ninety-one non-CDM mothers with macrosomia were studied and compared with 41normoglycemic subjects without macrosomia.Of the subjects with non-GDM macrosomia,45(49.4%)had normal SO g glucose challenge test(GCT)without further testing,another 8(8.8%)had abnormal GCT but normal 75 g oral glucose tolerance test(OGTT).A total of 4(4.4%)subjects had normal GCT and OGTT.Interestingly.14 out of 16(87.5%)subjects who were tested with OGTT owing to past history of macrosomia had normal results but delivered macrosomic babies.Only 12 subjects had both GCT and OGTT,the rest of the cohort had either of the two tests.Subjects with non-CDM macrosomia had higher frequency of neonatal hypoglycaemia 34%as compared to 10%in nonmacrosomic babies(P=0.003).Other feto-maternal complications were similar in both groups.Conclussions:No significant pattern of glucose tolerance characteristics was identified in nonGDM mothers with macrosomic babies.In spite of being normoglycemic significant neonatal hypoglycaemia was recorded in non-GDM macrosomic babies.Further prospective studies on a larger population are needed to verify our findings.

Declining diagnostic accuracy of non-invasive fibrosis tests is associated with elevated alanine aminotransferase in chronic hepatitis B

AIM To explore the effect of alanine aminotransferase(ALT) on the performance of non-invasive fibrosis tests in chronic hepatitis B(CHB) patients. METHODS A total of 599 treatment-naive and biopsy-proven CHB patients were included in the study. The cohort was divided into the following three groups: Normal ALT(ALT ≤ 40), slightly elevated ALT(40 < ALT ≤ 80) and elevated ALT(ALT > 80). The diagnostic performance of five common non-invasive fibrosis tests for liver fibrosis(stages S2-4), including the aspartate aminotransferase(AST)-to-platelet(PLT) ratio index(APRI), fibrosis index based on 4 factors(FIB-4), King's score, Forns index and gamma-glutamyl transpeptidase(GGT)-to-PLT ratio(GPR), were evaluated for each group. RESULTS Higher ALT levels were associated with higher non-invasive fibrosis test scores. Patients with the same fibrosis stage but higher ALT levels showed higher noninvasive test scores. The areas under the receiver operating characteristics curves(AUROCs) of the noninvasive tests for prediction of ≥ S2 were higher for patients with ALT ≤ 40 U/L(range 0.705-0.755) and 40 < ALT ≤ 80 U/L(range 0.726-0.79) than for patients with ALT > 80 U/L(range 0.604-0.701). The AUROCs for predicting ≥ S3 and S4 were higher in patients with ALT ≤ 40 U/L(range 0.736-0.814 for ≥ S3, 0.79-0.833 for S4) than in patients with 40 < ALT ≤ 80 U/L(range 0.732-0.754 for ≥ S3, range 0.626-0.723 for S4) and ALT > 80 U/L(range 0.7-0.784 for ≥ S3, range 0.662-0.719 for S4). The diagnostic accuracy of the non-invasive tests decreased in a stepwise manner with the increase in ALT.CONCLUSION ALT has a significant effect on the diagnostic performance of non-invasive fibrosis tests. The ALT level should be considered before performing these noninvasive tests.