Inspection of Bingo Bridge by using high-sensitivity magnetic nondestructive testing

High flux X-ray imaging detectors with spectroscopy capabilities are of particular interest for security and non-destructive testing applications. Multix S.A. has developed a linear array spectrometric detector, known as the ME100, able to provide a fully resolved energy spectrum over 128 energy bins, in real time and under high photon flux. Primary in this paper we present the ME100 detector performances compared to the simulations. Then we present results obtained with the ME100 detector showing the benefits of using multi-energy X-rays through two examples: 3 materials decomposition to recover the linear attenuation and highly precise fat in meat quantification for non-destructive testing (NDT).

Formulas for different loading cases of suspension bridges are presented. Although theoretically not correct, the principle of superposition can be used to get practical answers that are sufficiently accurate for determining stresses, deflections, and rotation in a stiffening truss or girder. The horizontal cable tension H is computed using the more accurate method by Steinman or the approximate method by Tsien. With H known, the differential equation for the various loadings can be resolved, and the results of such computations are shown in this paper. A numerical example is worked out to clarify the mathematical procedure. The data are from the Angostura suspension bridge over the Orinoco River in Venezuela.

The application of Non-Destructive Testing (NDT) techniques (dielectric spectroscopy, thermal conductivity and thermal activity) to different polymers, including fibre reinforced materials with and without voids is described. The NDT results are shown to correlate well with the structural parameters of the polymers.

Most reservoirs built in earlier years in China generally have major safety issues and leakage is a common problem with them. Nowadays as the technology of Non-Destructive Testing (NDT) has developed and matured greatly, it has been widely used in detecting internal seepage channels, voids, cracks of the dam body and is showing obvious advantages in these aspects. This paper employed a method integrating geological radar (geo-radar) with ultrasonic detection to conduct safety test on the dam body of the Xidachuan Reservoir located in the Linjiang City of Jilin Province of China. The NDT discovered main leakage risk positions of the dam, gave a safety evaluation of the dam body, and proposed targeted treatment measures. NDT can quickly and accurately inspect the quality problems with the dam without causing damages to the structure and it can provide reliable guarantees for the quality of dam projects.

Some non-destructive testing methods (NDT) used in industry and adapted for forensic use were reviewed. These methods were X-ray radiography, eddy current thickness measuring, and magnetic thickness measuring. Examples of applications of these methods in vehicle forgery examinations are illustrated.

This paper deals with application of Barkhausen noise for analysis of surface integrity in turning and grinding operation. The stress state is analyzed in relation to tool wear. The results of measurements show that the residual stresses are not homogenous on the machined surface. This homogeneity depends on tool wear and stability of cutting process. Application of non-destructive testing through the Barkhausen noise is more suitable for grinding operations. Application of Barkhausen noise testing for turning operation will require the next research.

Recently 3-D cone-beam tomography has become of interest for the nondestructive evaluation of advanced materials. The main field of application in nondestructive testing is the evaluation of structural ceramics. Study of such materials implies high density resolution and high sensitivity to cracks. In fact, with a single circular source trajectory, when the cone-beam aperture increases, density is underestimated and cone shaped artifacts may appear at interfaces in the sample even at relatively small aperture [1–3]. These artifacts limit the thickness we can examine with a planar source trajectory. To maintain optimal reconstruction accuracy with a circular source trajectory, the angular aperture must remain within ±10°. However Kudo and Saito [4] showed that this limit can be slightly overcome by using a special interpolation of the shadow area. But to examine greater thicknesses and to maintain resolution, we must widen the cone-beam aperture thereby decreasing accuracy. To overcome these aperture limitations, Tuy [5] introduced the double circular source trajectory idea.

Inspection of wall thickness of the evaporator walls is usually performed from the inside of the boiler with standard ultrasonic (UT) spot testing. The costs for this type of inspection is largely determined by the cost for scaffolding and grinding and by safety measures which sometimes even include radiation control. The necessity for grinding also slightly impacts the accuracy of the readings. A new non-destructive testing application has been developed which provides the possibility to do this inspection from the outside of a boiler and thus eliminating the need for scaffolding. Windows of interest of about 10 to 120 ft2 are selected and provisions in the boiler insulation are made. The tubes in the selected areas are tested through UT scanning. The minimum wall thickness of each tube in that window is graphically presented in a report and repeat measurements enable the plant owner to compare these values in time. Trends in wall thickness reduction provide a basis for boiler life time prediction and to take preventive action. As a tool for preinspection to assess required maintenance measures (such as overlay welding or tube replacement), this test application has already shown to be very valuable. Recent applications include wall thickness assessment of refractory covered wall tubes, testing of boiler wall tubing with internal wall thickness loss at the fire sided tube face and wall thickness assessment of Inconel clad tubes at waste incinerators (EU project: NextGen Biowaste). This paper will discuss the method of non-destructive testing of wall thickness of the evaporator walls from the outside and will present examples where this method is applied.

Disposable ultrasonic contact transducers have been constructed with inexpensive PVDF films for nondestructive testing (NDT) applications. This paper reports the temperature-dependent ultrasonic performance of commercial polyvinylidene fluoride (PVDF) films and PVDF sensors. PVDF film was evaluated for its material properties of interest for ultrasonic transducer performance including the relative dielectric constant /spl epsi//sub r/, dielectric loss tangent tan /spl delta//sub e/, electromechanical coupling constant k/sub t/, mechanical quality factor Q/sub m/, and acoustic impedance Z. Disposable PVDF transducers were then coupled to both low and high acoustic impedance test panels and their ultrasonic insertion loss/sensitivity and frequency bandwidth measured as a function of temperature in both the pulse-echo and pitch-catch modes. The results yielded center frequencies in the 3.5-16 MHz range, with -6-dB fractional bandwidths for some of the transducers exceeding 100%. The temperature dependence of the transducers' performance is reported for the -40 to 80/spl deg/C range and shows an approximate linear decrease in center frequency and increase in fractional bandwidth with increasing temperature. These measured results are compared with predictions from computer simulations based on Mason's model. These tests showed that the same disposable transducers can be used for both ultrasonic and acoustic emission sensing NDT applications. This paper summarizes the quantitative ultrasonic and vibration sensing performance for all of the disposable PVDF film transducers which were tested.

Simultaneous use of pulse-echo and through-transmission methods in determining a combined reflection coefficient

The process by which art paintings are produced typically involves the successive applications of preparatory and paint layers to a canvas or other support; however, there is an absence of nondestructive modalities to provide a global mapping of the stratigraphy, information that is crucial for evaluation of its authenticity and attribution, for insights into historical or artist-specific techniques, as well as for conservation. We demonstrate sparsity-based terahertz reflectometry can be applied to extract a detailed 3D mapping of the layer structure of the 17th century easel painting Madonna in Preghiera by the workshop of Giovanni Battista Salvi da Sassoferrato, in which the structure of the canvas support, the ground, imprimatura, underpainting, pictorial, and varnish layers are identified quantitatively. In addition, a hitherto unidentified restoration of the varnish has been found. Our approach unlocks the full promise of terahertz reflectometry to provide a global and detailed account of an easel painting’s stratigraphy by exploiting the sparse deconvolution, without which terahertz reflectometry in the past has only provided a meager tool for the characterization of paintings with paint-layer thicknesses smaller than 50 μm. The proposed modality can also be employed across a broad range of applications in nondestructive testing and biomedical imaging.

The classification of data with dynamically changing uncertainty characteristics is a problem for many practical applications. As an example in the field of nondestructive testing (NDT), magnetic flux leakage (MFL) measurements are used to inspect pipelines. The data is analyzed manually afterwards. In this paper we use a framework for handling uncertainties called Trust Management and a extended fuzzy rule based classifier to identify different installations within pipelines by MFL-data. The results show a classification performance of over 90% with an additional, reliable measure for the trustworthiness of every single classification result.

Microfabricated optically pumped magnetometers (OPM) are a novel class of commercially available quantum magnetometers combining high sensitivity with high dynamic range. In non-destructive testing (NDT) this should enable new applications like measuring stray fields arising from small stress concentrations affecting local magnetization. In ferromagnetic steel the sensitivity of OPM is sufficient to measure magnetization from critical stresses for crack initiation in submillimeter volumes. However, OPM, as they are built today, require additional components like magnetic flux guides to control the measurement volume in NDT systems. The improvement of spatial resolution with such a flux guide is demonstrated using neighbored weld seams as an example for stress concentrations.

Design of Low Frequency Piezoelectricity Transducer for Excitation of Pure A0 Lamb Wave and Its Application in Nondestructive Testing

The advanced method of mapping magnetic field and retrieving 2-D current distribution is investigated in this paper. A 16-channel anisotropic magnetoresistance sensor array scanner was implemented to quickly map the magnetic field. The algorithm used for calculating the current density distribution is the 2-D Fourier transform with properly chosen spatial filters. The spatial resolution for resolving the current distribution is 2 mm with a 2.5 mm gap. The proposed system is promising for applications in non-destructive testing, such as foreign object detection, field interference mapping for mobile device, and open and short circuits in printed circuit board.