Non-destructive Technology Research Articles

Failure Analysis of a Water Supply Pumping Pipeline System

This paper describes the most important results of a theoretical, experimental and in situ investigation developed in connection with a water supply pumping pipeline failure. This incident occurred after power failure of the pumping system that caused the burst of a prestressed concrete cylinder pipe (PCCP). Subsequently, numerous hydraulic transient simulations for different scenarios and various air pockets combinations were carried out in order to fully validate the diagnostic. As a result, it was determined that small air pocket volumes located along the pipeline profile were recognized as the direct cause of the PCCP rupture. Further, a detail survey of the pipeline was performed using a combination of non-destructive technologies in order to determine if immediate intervention was required to replace PCC pipes. In addition, a hydraulic model was employed to analyze the behavior of air pockets located at high points of the pipeline.

VIRTUAL PALEONTOLOGY—AN OVERVIEW

AbstractVirtual paleontology is the study of fossils through three-dimensional digital visualizations; it represents a powerful and well-established set of tools for the analysis and dissemination of fossil data. Techniques are divisible into tomographic (i.e., slice-based) and surface-based types. Tomography has a long predigital history, but the recent explosion of virtual paleontology has resulted primarily from developments in X-ray computed tomography (CT), and of surface-based technologies (e.g., laser scanning). Destructive tomographic methods include forms of physical-optical tomography (e.g., serial grinding); these are powerful but problematic techniques. Focused Ion Beam (FIB) tomography is a modern alternative for microfossils; it is also destructive but is capable of extremely high resolutions. Nondestructive tomographic methods include the many forms of CT, which are the most widely used data-capture techniques at present, but are not universally applicable. Where CT is inappropriate, other nondestructive technologies (e.g., neutron tomography, magnetic resonance imaging, optical tomography) can prove suitable. Surface-based methods provide portable and convenient data capture for surface topography and texture, and might be appropriate when internal morphology is not of interest; technologies include laser scanning, photogrammetry, and mechanical digitization. Reconstruction methods that produce visualizations from raw data are many and various; selection of an appropriate workflow will depend on many factors, but is an important consideration that should be addressed prior to any study. The vast majority of three-dimensional fossils can now be studied using some form of virtual paleontology, and barriers to broader adaptation are being eroded. Technical issues regarding data sharing remain problematic. Technological developments continue; those promising tomographic recovery of compositional data are of particular relevance to paleontology.

553 Complex skin models and impedance spectroscopy as new tools for dermatological research

The aim of this study was to improve current tests based on in vitro skin models both regarding a higher in vivo correlation and analytical methods. Despite advances in the development of in-vitro-tissue-models such as reconstructed human epidermis (RHE), the questions in dermatological research, which can be addressed with these models is limited. This is due to a lack of key cellular components and a restricted live time of the models. In addition, the analysis of the models is still dependent on invasive methods such as histological processing or MTT staining. To overcome these pitfalls, we achieved advanced culture systems and biomaterials which allow long term culture of complex tissue-equivalents. Using these technologies, we have developed the first full thickness skin-model with a perfused vascular network. Furthermore, as an alternative for destructive methods, we have established a non-destructive technology to analyze the integrity of the epidermal barrier based on impedance spectroscopy. RHE typically exhibits characteristic impedance spectra in a frequency ranging between 1 Hz and 100 kHz, which is comparable to the spectra of freshly isolated human epidermal biopsies. From these spectra, we extracted electrical parameters of the RHE such as the capacitance and the ohmic resistance. These parameters change significantly during epidermal differentiation and were used to quantify the effects of mechanical and chemical disruption of the epidermal integrity. Most relevant, impedance spectroscopy shows a sufficient sensitivity to detect a transient decreased ohmic resistance caused by 2-propanol, which is classified as a non-irritant by MTT assays. This result indicates that impedance spectroscopy can be employed as an additional method to assess mild irritative effects. In our work we could create new technologies for the generation and analysis of tissue-models which is a vital requirement to value of in-vitro-test-models for dermatological research.

Development of X-ray micro-focus computed tomography to image and quantify biofilms in central venous catheter models in vitro.

Bacterial infections of central venous catheters (CVCs) cause much morbidity and mortality, and are usually diagnosed by concordant culture of blood and catheter tip. However, studies suggest that culture often fails to detect biofilm bacteria. This study optimizes X-ray micro-focus computed tomography (X-ray µCT) for the quantification and determination of distribution and heterogeneity of biofilms in in vitro CVC model systems.Bacterial culture and scanning electron microscopy (SEM) were used to detect Staphylococcus epidermidis ATCC 35984 biofilms grown on catheters in vitro in both flow and static biofilm models. Alongside this, X-ray µCT techniques were developed in order to detect biofilms inside CVCs. Various contrast agent stains were evaluated using energy-dispersive X-ray spectroscopy (EDS) to further optimize these methods. Catheter material and biofilm were segmented using a semi-automated matlab script and quantified using the Avizo Fire software package. X-ray µCT was capable of distinguishing between the degree of biofilm formation across different segments of a CVC flow model. EDS screening of single- and dual-compound contrast stains identified 10 nm gold and silver nitrate as the optimum contrast agent for X-ray µCT. This optimized method was then demonstrated to be capable of quantifying biofilms in an in vitro static biofilm formation model, with a strong correlation between biofilm detection via SEM and culture. X-ray µCT has good potential as a direct, non-invasive, non-destructive technology to image biofilms in CVCs, as well as other in vivo medical components in which biofilms accumulate in concealed areas.

Evaluation of Asphalt Overlay Permanent Deformation Based on Ground-Penetrating Radar Technology

Abstract Permanent deformation in materials can lead to rutting on an asphalt pavement. Rutting poses potential hazard to vehicles running on the pavement because of hydroplaning during wet weather conditions. To mitigate or remedy rutting, it is of critical importance to identify the sources and causes of the permanent deformation. Traditional methods mainly rely on cutting a trench to approach this issue. Despite the accuracy, it is labor intensive and time consuming, not to mention having a destructive characteristic. To improve on these, this study discusses the feasibility of potential use of a non-destructive technology with ground-penetrating radar (GPR). GPR is used to estimate the permanent deformation in an asphalt overlay on top of an existing concrete pavement. The GPR antenna mounted on a moving vehicle could detect pavement layer thickness at a fast speed. It also provides full coverage on the pavement along the driving direction. The permanent deformation is estimated by comparing the layer thicknesses between the right wheel path and lane center. In particular, the results could reveal the permanent deformation involving the following three critical aspects: (1) in which layer(s) the permanent deformation occurs; (2) where the permanent deformation is located along the driving direction; and (3) how significant the permanent deformation is.

Technology of nondestructive light gas extraction from ice tested on samples from a bore hole above Vostok Lake

Nondestructive technology has been developed for the extraction of light gases dissolved in ice. The technology has been tested on samples of atmospheric and congealed ice of the 5-G3 bore hole of the Vostok station (East Antarctica) extracted from depths of 3457–3698 m. Down to 3539 m, ice is of an atmospheric origin, while ice deposited deeper is formed by natural water of Vostok Lake frozen on the glacier. Light gases were extracted into samplers (glass flasks) in the course of the 3-day degassing of samples freshly elevated from a bore hole. The samples were analyzed on the FT-1 time-of-flight mass spectrometer 6 months after sampling. Measurements reveal the presence of amounts of helium as well as molecular hydrogen considerably exceeding the atmospheric values. Measured values of gas ratio H2/4He = 5.4 ± 1.9 in the samples from depths of 3596–3698 m exceed the atmospheric values by more than an order of magnitude.

Color spaces of safflower (Carthamus tinctorius L.) for quality assessment

ObjectiveIn this study, safflower (Carthamus tinctorius L.) was taken as a representative example to examine the application of color characteristics to evaluate quality. MethodsA computer vision system was established for the objective and nondestructive assessment of color using image processing algorithms. Color parameters were investigated based on the RGB, L*a*b and HSV color spaces. The content of hydroxysafflor yellow A (HSYA), a major bioactive constituent of safflower, was determined by high-performance liquid chromatography. The relationship between HSYA content and color values was investigated by Pearson correlation analysis. A multiple linear regression model was established to predict the HSYA content from color values. ResultsThe red color and lightness of safflower were found to be significantly related to HSYA content. The prediction equation obtained by multiple regression was reliable with an R2 value of 0.805 (P < .01). ConclusionThe results suggest that the computer vision technique could be used as a promising and non-destructive technology for color measurement and quality evaluation of CHM.

Non-destructive Assessment of Guava (Psidium guajava L.) Maturity and Firmness Based on Mechanical Vibration Response

Storage potential and eating quality of guava (Psidium guajava L.) fruit depend on its maturity. Segregation of guava according to maturity and firmness measured using non-destructive technologies would help the industry to designate ripe fruit to immediate market and less ripe fruit for distant market (e.g., exportation). This research was conducted to evaluate the potential of experimental resonant frequency (fe) and elasticity index (EI) to estimate fruit firmness, which has been reported to be inversely correlated to its maturity. A maturity index (Im) was calculated as the ratio of total soluble solids/titratable acidity (TSS/TA). It was proved that TSS, TA, and Im were significantly correlated (P < 0.05) to skin firmness (Fs), flesh firmness (Ff), stiffness (S), and analytical resonant frequency (ωn), being S the attribute best fitted to Im (R2 = 0.77). Since it was observed that fe and EI were sensitive to changes in fruit firmness, both of them were explored as alternatives to predict Fs, Ff, S, and ωn of guava fruit. In some cases, EI improved the models to predict guava firmness traits (e.g., Fs vs fe had a coefficient of determination of R2 = 0.58, whereas for Fs vs EI, it was R2 = 0.62). The best model occurred when plotting ωn vs fe (R2 = 0.86), followed by S vs EI (R2 = 0.84), making these promising features for the development of a new practical application using frequency response measurement as a non-destructive method to assess guava maturity.

A general nonlinear magnetomechanical model for ferromagnetic materials under a constant weak magnetic field

Weak magnetic nondestructive testing (e.g., metal magnetic memory method) concerns the magnetization variation of ferromagnetic materials due to its applied load and a weak magnetic surrounding them. One key issue on these nondestructive technologies is the magnetomechanical effect for quantitative evaluation of magnetization state from stress–strain condition. A representative phenomenological model has been proposed to explain the magnetomechanical effect by Jiles in 1995. However, the Jiles' model has some deficiencies in quantification, for instance, there is a visible difference between theoretical prediction and experimental measurements on stress–magnetization curve, especially in the compression case. Based on the thermodynamic relations and the approach law of irreversible magnetization, a nonlinear coupled model is proposed to improve the quantitative evaluation of the magnetomechanical effect. Excellent agreement has been achieved between the predictions from the present model and previous experimental results. In comparison with Jiles' model, the prediction accuracy is improved greatly by the present model, particularly for the compression case. A detailed study has also been performed to reveal the effects of initial magnetization status, cyclic loading, and demagnetization factor on the magnetomechanical effect. Our theoretical model reveals that the stable weak magnetic signals of nondestructive testing after multiple cyclic loads are attributed to the first few cycles eliminating most of the irreversible magnetization. Remarkably, the existence of demagnetization field can weaken magnetomechanical effect, therefore, significantly reduces the testing capability. This theoretical model can be adopted to quantitatively analyze magnetic memory signals, and then can be applied in weak magnetic nondestructive testing.

Comparative evaluation of nondestructive devices for measuring pavement thickness in the field

Estimating pavement surface thicknesses without requiring large footprint equipment or pavement repairs is critical for the structural evaluation of airfield pavement. A research team from the U.S. Army Engineer Research and Development Center conducted an evaluation of eleven nondestructive technologies, including eight ground penetrating radar (GPR) devices and three wave propagation technologies, on twenty-one hot-mix asphalt concrete (AC) and nineteen portland cement concrete (PCC) test locations with varying pavement thicknesses. The different technologies were used to estimate pavement thickness over predetermined test points. For each pavement structure, a core was extracted from one of the test points to provide calibration data of each testing device for data refinement. The accuracy of each technology was quantified by calculating the absolute difference between the actual core measurement and the estimated thickness measurement. The results from the devices tested led to the conclusion that separate devices are required on AC and PCC for optimal performance. The ultrasonic tomography and impact echo devices worked best on PCC surfaces, and the 1GHz horn antenna GPR devices performed best on AC surfaces. The side-by-side testing demonstrated the capabilities of the technologies on varying pavement structures without discrepancies that would likely occur when comparing one set of results to those from a different study.

Nondestructive monitoring of subsurface damage progression in concrete columns damaged by earthquake loading

The assessment of the structural integrity of infrastructure after extreme events is an important application of nondestructive technology. Advancements in elastic wave-based methods in recent years have allowed for productive and accurate quantitative analysis which was previously lacking. In this study, ultrasonic array measurements coupled with a modified signature analysis method were implemented for damage detection purposes. Full-scale testing of a reinforced concrete column subjected to simulated earthquake loading was tested using ultrasound nondestructive testing at various stages of loading. A signature analysis technique was adapted to create improved reconstructions and was coupled with a quantitative analysis incorporating Pearson’s correlation coefficient. The results demonstrated the ability to detect internal damages and defects prior to appearance on the surface using one-sided access, showing promise for health monitoring applications.

第52回X線材料強度に関する討論会 「企業における非破壊検査の現状と課題および放射光を利用した非破壊材料評価技術の現状と課題」開催報告

第52回X線材料強度に関する討論会 「企業における非破壊検査の現状と課題および放射光を利用した非破壊材料評価技術の現状と課題」開催報告

1310 nm Source Spectral-Domain Optical Coherence Tomography for Chinese Pigment and Jadeite Research

Optical Coherence Tomography (OCT) technique is a nondestructive optical detection technology based on low-coherence interferometer and it has become an attractive cultural heritage research method. A 1310 nm source spectral-domain optical coherence tomography (SD-OCT) system based on optical fiber Michelson interferometer and optical spectrum analyzer is proposed and demonstrated for Chinese cultural heritage research. The cross-section OCT images of Chinese pigment samples and jadeite samples can provide a lot of valuable microstructure information for the Chinese cultural heritage research and identification works.

GPR Application – Non-destructive Technology for Verification of Thicknesses of Newly Paved Roads in Slovakia

The paper focuses on the use of non-destructive testing technology for measurement of asphalt and unbound pavement structure layer thicknesses for quality control and quality assurance within the context of civil engineering project handover process. In addition to layer thickness information, the pavement roughness was also verified using 3D accelerometer technique and IRI parameters were calculated and analyzed. This presentation summarizes the technology and results of a project where a special section of highway R2 Žiar nad Hronom bypass in the length of 5.2km was selected for the non-destructive testing. The processing and interpretation consists of extensive data sets presented as longitudinal profiles from survey of each lane of road. The designed layer thicknesses of the road were then compared with measured thickness data. In addition, a comprehensive presentation of the results in GIS view was produced to ensure the subsequent decision-making process easy to execute.

Detection and formation mechanism of micro-defects in ultrafine pitch Cu—Cu direct bonding*Project supported by the National Natural Science Foundation of China (Grant No. 61274111) and the National Basic Research Program of China (Grant No. 2015CB057205).

In this paper, Cu–Cu interconnects with ultrafine pad pitches of 6 μm, 8 μm, and 15 μm are implemented on the 12 inch wafers by a direct bonding process. Defects are not found by traditional non-destructive (NDT) c-mode scanning acoustic microscopy (c-SAM). However, cross sectional observation of bonding interfaces reveals that micro-defects such as micro seams are located at SiO2 bonding interfaces. In order to examine the micro-defects in the ultra-fine pitch direct bonding process by the NDT technology, a novel “defect-enlarged approach” is proposed. The bonded dies are first annealed in an N2 oven at 300 °C for a few hours and then cooled quickly in air. The c-SAM scanning images show large defects at the place where nothing can be detected by c-SAM before this treatment. Cross sectional observation of the bonding interfaces indicates that these defects consist of large size micro seams at the SiO2 bonding interface, especially near Cu pads with an ultrafine pitch of 6 μm. However, these large defects disappear after several hours at room temperature, observed by c-SAM. It is inferred that the disappearance of these defects inspected by the “defect-enlarged approach” results from the combination of intrinsic micro seams and “weak” bonds in the silicon oxide layer. Then the underlying physical mechanism of these micro-defects is proposed, which is influenced by Cu pad surface topology and bonding models.

Quantitative Ultrasound for Nondestructive Characterization of Engineered Tissues and Biomaterials.

Non-invasive, non-destructive technologies for imaging and quantitatively monitoring the development of artificial tissues are critical for the advancement of tissue engineering. Current standard techniques for evaluating engineered tissues, including histology, biochemical assays and mechanical testing, are destructive approaches. Ultrasound is emerging as a valuable tool for imaging and quantitatively monitoring the properties of engineered tissues and biomaterials longitudinally during fabrication and post-implantation. Ultrasound techniques are rapid, non-invasive, non-destructive and can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, high-frequency quantitative ultrasound techniques can enable volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation. This review provides an overview of ultrasound imaging, quantitative ultrasound techniques, and elastography, with representative examples of applications of these ultrasound-based techniques to the field of tissue engineering.

A single-probe capillary microgripper induced by dropwise condensation and inertial release

A micromanipulation method based on liquid droplets is widely used as a non-destructive technology to pick-and-place micrometer-scale objects. We focus on the development of a single-probe capillary microgripper to execute reliable micromanipulation tasks. By controlling dropwise condensation on a probe tip, the water droplet volume on the hydrophobic tip surface can be varied dynamically, which helps establish appropriate capillary lifting forces during capturing tasks. An inertia-releasing strategy was utilized to implement a piezoelectric actuator integrated with the capillary microgripper and to address release problems caused by adhesion force action. The influence of droplet formation and the capillary lifting force generated during the manipulation process were characterized experimentally. Micromanipulation tests were conducted using a customized motion platform with viewing microscopes to verify the performance potential of the capillary microgripping tool. Experimental results indicated that polystyrene microspheres with 20–100 μm radii and micro-silicon chips (1.63–12.1 μN) were grasped reliably, and that adhered micro-objects could be placed on a target using the proposed microhandling technique of inertial release in ambient conditions.

A LOW COST NIR BASED EMBEDDED SYSTEM FOR FRUIT QUALITY ASSESSMENT

India is one of the largest producers of fruits in the world.Banana, pineapple and mango are the major fruits produced in our country. In fruits, internal defects, presence of worms, etc. needs to be detected. Recently Computer Vision System (CVS) and image processing are used for evaluating external visual quality factors such as colour, shape, etc. Various non-destructive technologies such as VIS/NIR spectroscopy, ultrasonic, X-ray and MRI are used for evaluating internal quality factors such as sugar content, acid content, etc. But in India, there is lack of such improved technologies and instrumentation for getting right information about quality since these techniques are highly expensive. Thus sorting of fruits is done manually. In manual sorting, it is hardly possible to detect the internal defects.This has resulted in rejection of fruits for export from India. Thus there is a need to develop an embedded system to detect the internal defects including the presence of worms in fruits. In this work NIR based imaging is used for low cost detection of presence of worms in fruits.

Research on the Multi-Actuator and Sensor Detecting Technology Based on Piezoelectric Composite Materials

Traditional ultrasonic methods are popular in identifying easily detectable cracks, but are not good enough in minute crack detection. Early damage identification is important in preventing larger crack development and future catastrophes. Highly sensitive and precise actuator/sensor is employed to improve the detection capability of these minute cracks. The Orthotropic Piezoelectric Composite Material (OPCM) has been developed as a functional material that can be conveniently used as a highly sensitive actuator/sensor. Comparing the OPCM with the traditional elements, the former has the ability of exciting and receiving focus power and directional strain waves. They have been used in non-destructive technology in many structural engineering inspections. Using the filtering capabilities of the OPCM sensor and Hilbert-Huang Transform (HHT) method, the experimental results show that by using the multi-actuator and sensor, the simulated cracks inside aluminum plane specimen can be successfully identified.

Experimental on infrared radiation characteristics of high strength concrete during fracturing process

In order to achieve the concrete structures damage detection by using non-destructive technology, this paper analyzes the variation characteristic of the infrared radiation and researches the infrared anomaly precursor of the concrete structures damage in the high speed railway infrastructure. The results show that the concrete sample will radiate infrared heat under the influence of the uniaxial loading, and the thermal infrared radiation increase with the increasing stress. The temperature raise quickly in the late loading stage, however, the temperature decreases before the burst of the concrete. The feature of the high-temperature region surrounds the low-temperature field is the main characteristics of the thermal image, and the infrared anomaly precursor, which is a high and low temperature boundary line, will appear before the burst of the sample. The experimental result will provide the detection basis for the non-destructive-testing and safety monitoring on concrete foundation of high speed railway.