Papers by Keyword: Diagnostics

Abstract: Positron annihilation spectroscopy (PAS) offers a transformative approach to medical imaging, providing detailed insights into molecular structures. Although PAS has been extensively applied in studying defects in semiconductors and synthetic materials—yielding quantitative data on their microscopic properties—its potential in medical imaging could significantly enhance diagnostic methodologies. The application of positrons and other forms of radiation in analyzing living tissues necessitates careful consideration of potential damage. In this work, a model method designed to determine the optimal dose for experimental measurements is introduced. While Positron Emission Tomography (PET) has been instrumental in clinical diagnostics using radiopharmaceuticals to visualize metabolic processes, PAS presents a cutting-edge tool for improving the specificity and accuracy of biological imaging. Its capability to non-destructively explore structural transformations and micro-environmental changes in biological samples positions it as a promising innovation in diagnostics, paving the way for enhanced healthcare outcomes globally.

Abstract: Water or moisture contained in any form in hydraulic oil is not desirable in a hydraulic system. It can cause emulsification of the oil, which results in deterioration or rupture of the lubricating film, as well as corrosion of metal parts in this system. This corrosion can cause damage to metal parts and impair their functionality. Regular control of the amount of water in hydraulic oil is therefore a very important part of hydraulic oil diagnostics. The article presents a case study of monitoring the condition of hydraulic oil for water content values, which were determined according to the Karl Fischer method. The analysis of hydraulic oil in the article was also an experimental drop analysis for monitoring water in hydraulic oil, which we classify as a quick and simple chemical method aimed at indicatively demonstrating the presence of water in oil and the degree of oil contamination. This analysis belongs to non-dismantling technical diagnostics. Its greatest advantage is that with its help, oil analysis is faster and cheaper compared to analyses performed in laboratories.

Abstract: This paper shows the application of discrete wavelet transform in the analysis of ECG signals to detect R-peaks of the QRS complex. The proper analysis of the ECG signal is crucial to reveal the changes in the waveform to detect heart related diseases. The detection of the P-wave, T-wave, QRS complex is important and the wavelet transform offers a good possibility to recognize the abnormalities. Three different wavelets, Symlet, Coiflet and Daubechies are used for the detection and are compared to choose the most efficient one to identify the R-peaks. Multiresolution analysis (MRA) is used to determine the sufficient level of decomposition. MIT-BIH Arrhythmia Database is used as a dataset for the experiment.

Abstract: Determining the load-carrying capacity of existing bridges is a crucial task in assessing the current reliability and remaining service life of prestressed concrete structures and bridges. Nowadays, prestressed bridge structures that have been in operation for more than sixty years are proving to be problematic from the reliability point of view. If we want to comprehensively assess the reliability level of these structures, it is necessary to determine the current level of the prestressing as accurately as possible. This fact leads to the need to apply different methods that can determine these values. The paper is focused on the analysis of prestressing using indirect or analytical-experimental methods. Specifically, the Structural Response Method and the Saw-Cut Method. These techniques were tested both on prestressed members, in laboratory conditions, but mainly directly in-situ on a post-tensioned bridge. Finally, the experimental results are compared with the theoretically determined levels of prestressing.

Abstract: Building industry is an important player that consumes a significant part of raw materials and energy. With regard to construction industry sustainable development and design requirements there is a space for innovative solutions, where one of the possibility include the use of high-strength concrete. The paper deals with the substantial description and detailed evaluation of the testing of reinforced high strength concrete beam which was exposed to three point loading test. Large scale experiment was complemented with material diagnosis of selected mechanical properties using destructive and non-destructive methods. Non-destructive methods were used to verify compressive strength and dynamic modulus of elasticity. Destructive compressive strength testing was applied on cylinder samples prepared with core drilling and determined values were compared with non- destructive testing. Measured data will be used for future advanced non-linear modelling.

Abstract: The paper deals with diagnostics, recalculation, and determination of the current load capacity of three concrete arch bridges on the original railway line Bratislava - Žilina. This was built in 1954 in connection with the relocation of the line, caused by the exhibition of the Nosice reservoir. At present, the railway line has been relocated to a new location and the existing original line, including the existing engineering facilities, will be used for the construction of a new road connecting the district towns of Púchov and Považská Bystrica. The task was solved within the cooperation of Faculty of Civil Engineering with the Railways of the Slovak Republic (ŽSR in Slovak) and the Research and Development Institute of Railways (VVÚŽ in Slovak). The conclusions from the recalculations and the subsequently determined load capacity show that the bridge structures in question are suitable for further use, however, their reconstruction is necessary.

Abstract: The paper is focused on diagnostics and calculation of load-carrying capacity of the two atypical girder bridge objects on the railway line between Púchov and Považská Bystrica in Slovakia. These are skewness reinforced concrete (RC) girder bridges with three girders. The non-typicality is given by the fact that the spandrel girders are in the longitudinal direction, but the middle girder is relatively wide and is perpendicular to the clearance (not in the longitudinal direction). The diagnostics was performed on the objects aimed at determining the material and geometric characteristics, which served as a basis for the numerical model. A 3D scanner was also used to determine the geometric dimensions. The load-carrying capacity was subsequently determined on the bridges. The recalculation and diagnostics revealed the fact that bridge structures can still be used, but have to be reconstructed. This is a prime example of reusing in practice, i.e. how the old bridges can be further used, which means a significant saving of CO₂ emission that would be produced by demolishing the old bridges and building new ones

Abstract: Chimneys are high-rise buildings indispensable for the operation of important plants in industry and in energy. The paper deals with the description and evaluation of defects found on reinforced concrete structures in the chimney interspace. The object of the inspection was a chimney with a reinforced concrete monolithic stem and an offset protective casing. The space between the housing and the stem is ventilated. During the operation of the chimney, aggressive condensate penetrates into the interspace, as a result of which unprotected reinforced concrete structures can degrade.

Abstract: Technologically, ultrajet mesodiagnostics (UJM) consists of local hydroerosive indentation by ultrajets (UJ) of water on the surface of the analyzed object (OA) and the subsequent study of the results of this minimally invasive microdestructive effect on its surface layer. Obviously, mathematical models’ construction of the functional relationship between the informative-physical signs of hydroerosive UJ destruction and the surface layer’s state parameters of various OA, primarily their defectiveness, is very important for the development of this potentially promising technology for ensuring the quality of critical products, mainly aviation and other industries. In this regard, the work proposes a probabilistic UJM model, which consists of analyzing the kinetics of the formation of an aggregate set of eroded particles, as a process caused by a combination of appropriate necessary and sufficient conditions for its implementation. The former include the topographic features of the microdefectiveness’ characteristics of the surface layer material, and the latter consist of a certain variational-force hydrodynamic effect of the diagnostic UJ on it. This approach made it possible to obtain calculated data related to probabilistic distribution of the UJ-eroded particles’ sizes of hypothetical OA, as a coordinate function describing the microdefects’ concentration in its surface layer. These functions are close to the available results of experimental UJM of typical and promising materials used in the manufacture of machinery technology.

Abstract: A method for manufacturing the titanium alloy NT-50 nanofibers (1-20) microns in a composite assembly is proposed. The undamaged nanofibers production conditions are determined. Nanofibers are used to create new products: diagnostic sensors for ophthalmology.