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Abstract: Humans are frequently exposed to environmental hepatotoxins, which can lead to liver failure. Biosensors may be the best candidate for the detection of hepatotoxins because of their high sensitivity and specificity, convenience, time-saving, low cost, and extremely low detection limit. To investigate suitability of HepG2 cells for biosensor use, different methods of adhesion on stainless steel surfaces were investigated, with three groups of experiments performed in vitro. Cytotoxicity assays, which include the resazurin assay, the neutral red assay (NR), and the Coomassie Brilliant Blue (CBB) assay, were used to determine the viability of HepG2 cells exposed to various concentrations of aflatoxin B1 (AFB1) and isoniazid (INH) in parallel. The viability of the HepG2 cells on the stainless steel surface was quantitatively and qualitatively examined with different microscopy techniques. A simple cell-based electrochemical biosensor was developed by evaluating the viability of the HepG2 cells on the stainless steel surface when exposed to various concentrations of AFB1 and INH by using electrochemical impedance spectroscopy (EIS). The results showed that HepG2 cells can adhere to the metal surface and could be used as part of the biosensor to determine simple hepatotoxic samples.
Keywords: HepG2 cell line, impedance biosensor, adhesion, hepatotoxins, stainless steel
Published in DKUM: 10.04.2025; Views: 0; Downloads: 3
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Abstract: This paper describes the non-contact vibration monitoring of prestressed reinforced concrete railway sleepers. The monitoring was carried out using physical measuring equipment consisting of a seismograph and geophones, a robotic total station (RTS) and scanning laser Doppler vibrometry (SLDV) equipment. Measurements of the dynamic response of sleepers to the dynamic loading induced by the running of train sets provides data that give an insight into the actual state of the sleeper structure at the moment when it is most stressed. The main objective of the study was to identify the most appropriate form of monitoring to monitor events related to the occurrence of cracks in the rail sill, which can also be caused by the impact of vibration. As is well-known, monitoring the dynamic response of railway sleepers is very important for the sustainable management and maintenance of railway lines. The vibration analysis was carried out in the field on the Ormož–Ptuj section of the railway line, in Velika Nedelja and in the laboratory of the UM FGPA, where the vibration was simulated using a hydraulic kit with a static and pulsed force of 100 kN. Several cycles of measurement were carried out and the results were compared with the results of the field monitoring. The vibration parameters measured for the concrete sleepers are necessary to develop a realistic dynamic model of the railway line, which will be able to predict its response to impact loads and the possible occurrence of damage, as has recently been observed for concrete sleepers in several European Union countries.
Keywords: monitoring, measurement equipment, railway line, displacements, deformations
Published in DKUM: 12.03.2025; Views: 0; Downloads: 5
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Abstract: The increasing adoption of 2D/3D laser line sensors in industrial and research applications necessitates accurate and efficient simulation tools for tasks such as surface inspection, dimensional verification, and quality control. This paper presents a novel algorithm developed in MATLAB for simulating the measurements of any 2D/3D laser line sensor on STL CAD models. The algorithm uses a modified fast-ray triangular intersection method, addressing challenges such as overlapping triangles in assembly models and incorporating sensor resolution to ensure realistic simulations. Quantitative analysis shows a significant reduction in computation time, enhancing the practical utility of the algorithm. The simulation results exhibit a mean deviation of 0.42 mm when compared to real-world measurements. Notably, the algorithm effectively handles complex geometric features, such as holes and grooves, and offers flexibility in generating point cloud data in both local and global coordinate systems. This work not only reduces the need for physical prototyping, thereby contributing to sustainability, but also supports AI training by generating accurate synthetic data. Future work should aim to further optimize the simulation speed and explore noise modeling to enhance the realism of simulated measurements.
Keywords: 2D/3D laser line sensor, profilometry, simulation, point cloud, measurement generation, STL, Matlab
Published in DKUM: 10.01.2025; Views: 0; Downloads: 10
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Abstract: The paper presents a new algorithm for reflection symmetry detection, which is specialized to detect maximal symmetric patterns in an Earth observation (EO) dataset. First, we stress the particularities that make symmetry detection in EO data different from detection in other geometric sets. The EO data acquisition cannot provide exact pairs of symmetric elements and, therefore, the approximate symmetry must be addressed, which is accomplished by voxelization. Besides this, the EO data symmetric patterns in the top view usually contain the most useful information for further processing and, thus, it suffices to detect symmetries with vertical symmetry planes. The algorithm first extracts the so-called interesting voxels and then finds symmetric pairs of line segments, separately for each horizontal voxel slice. The results with the same symmetry plane are then merged, first in individual slices and then through all the slices. The detected maximal symmetric patterns represent the so-called partial symmetries, which can be further processed to identify global and local symmetries. LiDAR datasets of six urban and natural attractions in Slovenia of different scales and in different voxel resolutions were analyzed in this paper, demonstrating high detection speed and quality of solutions.
Keywords: computer science, approximate symmetry, partial symmetry, local symmetry, point cloud, voxel, line segment
Published in DKUM: 28.09.2023; Views: 438; Downloads: 37
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Abstract: This study presents an approach to solving the assembly line balancing problem (ALBP) using the Methods-Time Measurement (MTM) time standard and simulation software. ALBP is a common problem in manufacturing where a set of tasks with fixed times must be assigned to a series of sequential workstations in order to minimize the total idle time and reduce the assembly cost per product. This study uses MTM, a widely used production process scheduling method, to create a new time analysis of an assembly process that was previously balanced using the Work-Factor method and time study. This literature review shows that there are a lack of combinations of updated time analyses with newer simulation approaches in the current literature, and this was the motivation for the present work. An assembly line simulation was performed using Simio software to evaluate different design options and operating scenarios. The results show that the use of MTM and simulation can help minimize idle time and improve assembly line performance, thereby reducing costs and increasing efficiency. This study shows that the approach of using MTM and simulation is effective in solving ALBP and is a useful tool for manufacturing companies to improve the performance of their assembly lines and reduce costs.
Keywords: optimization, production planning, assembly line, MTM time standard, simulation, industry 4.0
Published in DKUM: 23.05.2023; Views: 533; Downloads: 112
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