Papers by Keyword: Nondestructive

Abstract: Tapioca starch adulterated with dolomite is sold in markets, but this adulteration cannot be identified by normal visual inspection. Near infrared (NIR) hyperspectral imaging has been successfully used as a non-destructive method of identifying various characteristics of food, therefore it was tested to identify dolomite adulteration. Adulterated tapioca starch samples were prepared by adding dolomite in the range of 0.5-100% (wt/wt). Samples (N=400) of pure tapioca starch (0) and adulterated tapioca starch (1) were divided into calibration set (N=300) and a prediction set (N=100). All samples were scanned using NIR hyperspectral imaging (935-1720 nm) and spectra were pre-processed using Savitzky-Golay first derivative differentiation pretreatment in order to obtain the optimal conditions for establishing a classification model. Partial least squares-discriminant analysis was carried out to evaluate the accuracy of classification tapioca starch adulterated with dolomite. The results showed the total accuracy of prediction for classification was 100%. Therefore, NIR hyperspectral imaging was demonstrated to have a potential for use in detecting adulteration of tapioca starch with dolomite.

Abstract: Nondestructive determination of Au in gold ornaments mainly takes density method and X ray fluorescence spectrometer with energy dispersion (EDXRF), which exists disadvantages. This paper based on the principle of crystallography, deduced the mathematical relationship between the crystallographic parameters, the density and the impurities content in gold jewelry alloys, then introduced the results by density testing and determination of Ag and Cu by EDXRF into the mathematical relationship, and obtained the gold weight percent in gold jewelry alloys. The results show that obtained the gold weight percent and determination of Au by fire assay are almost consistent, which the error is less than 0.12 %, so establishes a synthesis method of determination of Au by EDXRF and density testing, solves the disadvantages which EDXRF only detects on gold jewelry surface and small area, and density testing cannot detect gold jewelry alloy and demands that jewelry shape is simple, and provides an effective synthesis way for determination of Au in gold jewelry alloys.

Abstract: Factors such as poor design, bad workmanship and a harsh environment can combine to cause deterioration within a concrete structure leading to visually unacceptable surface cracking or spalling of concrete cover [. In aggressive environments, corrosion of steel reinforcing bars is responsible for major deteriorations in concrete structures. Reduction in bar diameter leads to a lower resistance, which can result in brittle failure of the bar. Initiation and progression of reinforcing steel corrosion can lead to progressive weakening of the structure due to damage accumulation over a period of time, or in sudden catastrophic failures, such as the Berlin Congress Hall, a parking garage in Minnesota [. Antonaci et al. [ conducted an experimental study on different concrete cylinders damaged in compression followed by means of linear and nonlinear ultrasonic methods. Arndt et al. [ tested a concrete slab representing typical bridge decks in order to evaluate the ability of NDT methods to detect different phases of corrosion progression in concrete. Reinforced concrete beam-shaped samples were tested by Aveldano and Ortega [ in order to characterize concrete cracking due to reinforcing corrosion under different environments. Shah and Ribakov [ performed nonlinear ultrasonic testing of cubic concrete specimens with different frequency transducers. Al-Amoudi et al. [ investgated the relatioship between compressive strength of ordinary concrete and blended cement concrete with durability propeties of concrete samples and conculded that the addition of blended cement will improve the performance of concrete in ressiting corrosion of reinforcement. The main objective of this study is to investigate the effectiveness of using nondestructive testing to assess the performance of different types of concrete such as OPC and SFC. Also, to correlate different types of nondestructive testing and to investigate the possibility of capturing the occurrence of corrosion in reinforcing bars in concrete.

Abstract: It is of great significance to monitor and quantify the defects in the thin segmental spherical shell components. In the paper the guided wave’s inspiring method has been obtained from the wave-mode conversion based on the theory of the guided wave propagating in the thin spherical shell. Using the wavelet to process the testing signal, and the ellipse localization imaging algorithm, the defect’s localization and orientation can be detected accurately. Experimental results show the defect’s direction and location can be detected effectively and clearly.