Precise Non-destructive Testing Research Articles

Rapid and nondestructive watermelon (Citrullus lanatus) seed viability detection based on visible near-infrared hyperspectral imaging technology and machine learning algorithms.

The improper storage of seeds can potentially compromise agricultural productivity, leading to reduced crop yields. Therefore, assessing seed viability before sowing is of paramount importance. Although numerous techniques exist for evaluating seed conditions, this research leveraged hyperspectral imaging (HSI) technology as an innovative, rapid, clean, and precise nondestructive testing method. The study aimed to determine the most effective classification model for watermelon seeds. Initially, purchased watermelon seeds were segregated into two groups: One underwent sterilization in a dehydrator machine at 40°C for 36h, whereas the other batch was stored under favorable conditions. Watermelon seeds' spectral images were captured using an HSI with a charge-coupled device camera ranging from 400 to 1000nm, and the segmented regions of all samples were measured. Preprocessing techniques and wavelength selection methods were applied to manage spectral data workload, followed by the implementation of a support vector machine (SVM) model. The initial hybrid-SVM model achieved a predictive accuracy rate of 100%, with a test set accuracy of 92.33%. Subsequently, an artificial bee colony (ABC) optimization was introduced to enhance model precision. The results indicated that, with kernel parameters (c, g) set at 13.17 and 0.01, respectively, and a runtime of 4.19328s, the training and evaluation of the dataset achieved an accuracy rate of 100%. Hence, it was practical to utilize HSI technology combined with the PCA-ABC-SVM model to detect different watermelon seeds. As a result, these findings introduce a novel technique for accurately forecasting seed viability, intended for use in agricultural industrial multispectral imaging. PRACTICAL APPLICATION: The traditional methods for determining the condition of seeds primarily emphasize aesthetics, rely on subjective assessment, are time-consuming, and require a lot of labor. On the other hand, HSI technology as green technology was employed to alleviate the aforementioned problems. This work significantly contributes to the field of industrial multispectral imaging by enhancing the capacity to discern various types of seeds and agricultural crop products.

Eddy current analysis for predicting deterioration stages in alumina former radiant coils

The alumina former radiant coil is typically used as a high-temperature material. It is inevitable that the material undergoes deterioration after prolonged use. This deterioration is primarily caused by damage from the service environment and initiates carburization, resulting in a loss of its mechanical properties. Currently, the damage to the materials is only discovered when they are already broken and a precise non-destructive testing method to determine the extent of material deterioration before the damage occurs has not successfully been developed. Therefore, this research aims to study and analyze the deterioration and the causes of damage to alumina former radiant coil materials. Additionally, the study was conducted to establish a relationship between the extent of deterioration and the impedance phase angle using the eddy current test method. The experimental analysis included both as-received and in-service materials of alumina former radiant coil, which consisted of 45 % nickel by weight, 30 % chromium by weight and 4 % alumina by weight. The additional testing methods included microstructure and elemental analysis, deterioration distance measurement and impedance phase angle measurement. The results indicated that the deterioration was primarily caused by damage to the oxidation layer, facilitating the diffusion of carbon and initiating a carburization reaction on the surface of the coil. These factors unavoidably reduced the corrosion resistance of alumina former radiant coil materials. Furthermore, the reduction in chromium content as materials entered the deterioration stage led to increased hardness in the carburization zone and reduced hardness in the oxidation zone. This deterioration caused the material to exhibit ferromagnetic behavior. It was observed that as the area of deterioration increased, the size of the ferromagnetic regions also increased. Resulting in, the eddy current testing results show a variation in the impedance phase angle. Therefore, the relationship can be concluded that the impedance phase angle increases in the counterclockwise direction, corresponding to a greater extent of deterioration. The benefit of this paper is to forecast the level of the severity of deterioration quantitatively when using eddy current testing.

Nondestructive inspection of packaged microcircuits by aperture-type terahertz near-field imaging

A scanning aperture-type terahertz near-field imaging system is developed to perform precise nondestructive testing on packaged aluminum etched antenna arrays, and surface imaging of a flexible gold electrode array, to obtain subsurface imaging and surface imaging. The resolution of subsurface imaging is 110 and 500 μm when the packaging (polyethylene terephthalate) thickness is 50 and 200 μm respectively, and the surface imaging resolution is 6 μm at 0.11 THz. An adaptive threshold segmentation algorithm of Hilbert scan combined with wavelet transform were employed to successfully suppress the noise of the imaging results due to the change of near-field distance. We also proposed a derivative filtering extremum threshold segmentation algorithm to effectively suppress severely uneven threshold distribution of the packaged aluminum etched antenna arrays.

Cold Working Degree Determination in Low Carbon Steel with Barkhausen Noise Analysis

Mild steel is one of the most commonly used materials in both industry, construction and other commercial –less or more elaborated- applications, and therefore the need of the appliance of an efficient and precise non-destructive testing method is requisite and mandatory. Here we report the experimental study of one of the most significant properties of mild steel, that of hardness, that can substantially reveal important facts such as the grade of deformation and work-hardening of steel, with the use of Barkhausen Noise Analysis. We also studied how the magnetic and mechanical properties of this specific metallic material can be successfully correlated.

Imperfections in friction stir welded zones and their precision non-destructive testing–studies on characteristics of friction stir welded joints in structural aluminium alloys (Report 1) –

Imperfections in friction stir welded zones and their precision non-destructive testing–studies on characteristics of friction stir welded joints in structural aluminium alloys (Report 1) –

Non-destructive defect characterization of concrete structures reinforced by means of FRP

The aim of this work is to develop a reliable and precise non-destructive testing technique based on infrared thermography and post processing by means of neural networks. In particular, the experimental procedure to be implemented consists mainly in the “impulsive” heating of the structure and in the analysis of the superficial thermal response by means of a thermocamera. The procedure requires a detailed set-up, in order to assess its feasibility. In this work is presented the case study of a concrete structure strengthened by bonded FRP, with imposed well-known defects. The results obtained by means of infrared thermography were compared with results obtained by ultrasonic testing.

Imperfections in friction stir welded zones and their precision non-destructive testing. Studies on characteristics of friction stir welded joints in structural thin aluminium alloys

The purpose of this study is to investigate various characteristics of thin aluminium alloy structural plate joints welded by the friction stir welding (FSW) process. A number of reports have been published concerning these characteristics. Most of these reports concern joints made by the relevant company's unique procedures using selected parent materials; consequently, the joints were made under restricted specified conditions. Accordingly, for this study, welded joints were produced by combinations of identical alloy base metals manufactured by several companies using the friction stir welding process with procedures which are unique to each individual company; an investigation was carried out into a variety of characteristics whilst attention was paid to the differences due to variations in the base metal and welding procedures.

Studies on Characteristics of Friction Stir Welded Joints in Structural Thin Aluminium Alloys Part 1: Imperfections in Friction Stir Welded Zones and Their Precision Non-Destructive Testing

By applying ultrasonic phased array testing selected as precision non-destructive testing to friction stir welded zones of 5083-O, 6N01-T5 and 7N01-T5 alloys with 3 mm thickness for parent materials, the detectability of imperfections in their zones was studied in comparison with both actual imperfections and current non-destructive testing. Significant noise resulting from the surface flash on the joint was indicated as band-like signals and in order to inspect accurately, the removal before testing or the testing from both sides was proposed. A small and thin planar cavity localized and included inside the stirred zones and also a small lack of penetration could be detected, which seemed to be almost impossible to detect by current testing. Further study was considered to be required, towards the practical use, such as identification of size and shape of imperfections and effect of angle incident upon imperfections on signals intensity.

Resonant ultrasound spectroscopy for materials studies and non-destructive testing

Abstract The use of mechanical resonances to test properties of materials is older than the industrial revolution. Early documented cases of British railroad engineers tapping the wheels of a train and using the sound to detect cracks perhaps marks the first real use of resonances to test the integrity of high-performance alloys. Attempts were made in the following years to understand the resonances of solids mathematically, based on shape and composition. But Nobel Laureate Lord Rayleigh best summarized the state of affairs in 1894, stating ‘the problem has, for the most part, resisted attack’. More recently, modern computers and electronics have enabled Anderson and co-workers, with their work on minerals, and our work at Los Alamos on new materials and manufactured components, to advance the use of resonances to a precision non-destructive testing tool that makes anisotropic modulus measurements, defect detection and geometry error detection routine. The result is that resonances can achieve the highest absolute accuracy for any routine dynamic modulus measurement technique, can be used on the smallest samples, and can also enable detection of errors in certain classes of precision manufactured components faster and more accurately than any other technique.