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[en] Small-scale mechanical testing on irradiated materials is gaining popularity in the nuclear materials community due to the fact that mechanical property changes can be evaluated from shallowly ion-beam-irradiated materials as well as from small volumes of reactor-irradiated components. While the obvious benefits of accelerated research and reduction of radiation exposure are gained through these methods, these methods also target specific microstructural areas of interest. This paper presents a summary of current techniques that are utilized and outlines a path towards a more thorough understanding of small volume testing on irradiated materials.
[en] There are many different mathematical models that can be used to evaluate ah inspection system's Probability of Detection (PoD). Each model has a unique feature, These features can make one model more appropriate than another model. There are more than 12 commonly used PoD models used in NDT and each model has its own unique mathematical form. This article introduces each model and compares them to reveal their unique features. PoD is typically rather heavily explained using mathematics, but understanding the mathematics to a very deep level is not required to generate a good PoD curve. Computers take care of the heavy math. Having an understanding of the differences between model types is essential for creating a PoD that actually represents the inspection situation. This is the main reason behind having a selection of models. (author)
[en] The Probability of Detection (PoD) is a very useful aspect of an inspection. It is a measure of an inspection system and/or personnel's detection capabilities. The PoD can be used to quantify improvements to an inspection, as well as personnel performance changes. Although the PoD can be a useful NDT tool, it is not used extensively. This is mainly due to the complex mathematics behind the model. Evaluating a PoD has specific NDT requirements, as well as statistical requirements. (author)
[en] All NDT inspections use models. The number and type of models will vary between inspections. A qualified inspection will use a PoD model to evaluate detection capabilities. All techniques have some degree of calibration. Some calibration processes generate curves that are simple models. Parameters are the building blocks of models. Models can be generated to understand what happens to the results of an inspection when parameters change. Not all parameter variation will cause a decrease in a system's detection capability. For example, an increase in an indication's length will likely increase the chance of detection. Each variable or parameter involved in an inspection has natural variations. These variations will affect an inspection with different degrees. Evaluating when a change is significant becomes an important aspect in developing sound inspection techniques. This article addresses several techniques used to determine significance in changes between measurements. (author)
[en] In this study, the feasibility of hyperspectral reflectance imaging technique was investigated for the discrimination of viable and non-viable lettuce seeds. The spectral data of hyperspectral reflectance images with the spectral range between 750 nm and 1000 nm were used to develop PLS-DA model for the classification of viable and non-viable lettuce seeds. The discrimination accuracy of the calibration set was 81.6% and that of the test set was 81.2%. The image analysis method was developed to construct the discriminant images of non-viable seeds with the developed PLS-DA model. The discrimination accuracy obtained from the resultant image were 91%, which showed the feasibility of hyperspectral reflectance imaging technique for the mass discrimination of non-viable lettuce seeds from viable ones.
[en] Shape memory effect is the most effectively performed on NiTi shape memory alloy. The shape memory effect phenomena are related to solid-state phase transformation so the atomic neighbourhood orientation keeps during the phase transformation process. Stress and energy release during the phase transformation have effects on orientations of the atomic structure. However, if SMAs are exposure to repeated regular deforming and shape recovery cyclings, this will eventually cause some loses in their shape memory recoverability. In this study, the shape memory effect loss ratio of Ni46.84Ti53.16 (at%) alloy was investigated by systematic stress-strain mechanical tests and significant shifts was recorded on shape recovery ratios. (paper)
[en] Vibration monitoring is required for reliable thermosonic testing to decide whether sufficient vibration is achieved in each test for the detection of cracks. From a practical point of view, a cheaper and convenient monitoring method is better for the application to real tests. Therefore, the performance of different sensors for vibration monitoring was investigated and compared in this study to find a convenient and acceptable measurement method for thermosonics. Velocity measured by a laser vibrometer and strain provide an equivalent HI when measured at the same position. The microphone can provide a cheaper vibration monitoring device than the laser and the heating index calculated by a microphone signal shows similar characteristics to that calculated from velocity measured by the laser vibrometer. The microphone frequency response shows that it underestimates high frequency components but it is applicable to practical tests because it gives a conservative value of HI
[en] The article presents the modern methods of research of building materials (such as styrofoam, cement, concrete admixtures, etc.), applied in the Far Eastern Federal University. The latest equipment described for these studies and modern methods of testing. (paper)