Papers by Keyword: Measurement

Abstract: The widespread adoption of broadband networks has significantly boosted economic growth and transformed various sectors. While mobile broadband (MBB) has gained widespread acceptance due to its flexibility and mobility, fixed broadband (FBB) networks offer superior performance, supporting multiple users and devices without compromising speed. FBB's high-speed internet, stability, and large data capacity make it ideal for data-intensive activities like remote work, online learning, and video conferencing. However, ensuring reliable and high-quality services remains a concern, prompting researchers, governments, and regulators to develop unbiased performance measurement methodologies for FBB networks. This paper reviews existing approaches, tools, and frameworks for assessing Quality of Service (QoS) and Quality of Experience (QoE) in FBB networks, highlighting regional and stakeholder disparities. Key performance indicators like bandwidth, latency, jitter, and packet loss are examined, along with challenges related to measurement consistency, standardization, and transparency. The findings emphasize the need for robust, cost-effective, and transparent measurement frameworks to ensure fair evaluation, enhance service delivery, and promote digital inclusion globally.

Abstract: The carbonized materials structure levels from molecular to macrostructure is analyzed. A study was conducted to find correlations between the granular carbonized materials electrical resistance and other substance physicochemical properties. It is proven theoretically and experimentally that determining the electrical resistance for a granular material, rather than a finely ground sample, is a more informative indicator for reflecting the microstructural features of the material, its reactivity, strength, and clarifying the carbonization conditions. A method is developed for determining the granular materials electrical resistance in the rotating drum interelectrode space, with determination of the indicator value in the cold and hot state for the substance under investigation. An indicator of the granular matter electrical resistance based on the heating time to 670 °C at a drum power supply constant voltage is introduced. Calculated dependencies is obtained for predicting, based on experiment results, some quality indicators for such a carbonized material as metallurgical coke: structural strength, apparent density, reactivity, gasification degree, and electrical resistivity. Better correlations is achieved with these indicators than with the standard electrical resistance on the "micropress" device, which indicates a better reflection of the carbonized materials substance supramolecular structure.

Abstract: Nowadays, there is a spike in 3D printing and additive manufacturing technology all over the world. Starting from the prototype state to the final production process, a high demand is noticed due to the fact that this technology is rapid, economical and good-fit for finding out the mechanical behavior of the material and the structure. Thermoplastic polyurethane (TPU) is widely used in automotive industry, sport industry, medical industry, even in footwear industry. High abrasion resistance, shear strength, elasticity with low-temperature performance make TPU widely used and so important. In this study, we focused on the effect of infill pattern and density in mechanical behavior of 3D printed TPU part. We controlled the density and pattern both resulting in changing mechanical properties, helping us reduce the use of material, cost and production time accordingly. It is necessary to prepare a database on the test results, which can help us to understand the parameters related to internal structure or infill pattern of the material.

Abstract: As with any measuring device, it is important to install and operate water meters that are calibrated within an acceptable international standard (ISO) and regulatory acceptable relative error, in accordance with the requirements of the international standard. The article deals with the issue of correct installation of measuring devices during operation and checking on high-precision equipment. Production In order to increase the technical level and meet people's needs, there is a need to use the latest modern measuring tools of equipment and technology in the economy and production. For this reason, it is important to provide citizens with new measuring devices and provide them with regular technical service in our country. It is necessary to create modern equipment and laboratories for checking measuring instruments. As the devices are used, their life ends after a certain period of time, and they need to be checked. A malfunctioning device leads to incorrect information, incorrect calculations and losses, depending on where it is used for its intended purpose. By checking the measuring devices in modern laboratories with high accuracy, removing the defect and re-using it after calibration, we get correct calculations, correct information exchange, and elimination of losses. For example, the correct installation of water measuring devices was also checked on the error determination stand, and the results of their errors at different values ​​were automatically displayed in the error curve table.

Abstract: Naturally-occurring saturated fatty acids have been classified as the interesting biomaterials. Typically, the interfacial tension and wettability relying on intermolecular forces relate to the well-fitted performance with any target sites of in situ forming matrix. This research aimed to determine surface tension/contact angle of several saturated fatty acids in selected aprotic solvents commonly used in in situ forming system by varying fatty acid concentrations and molecular weights. Six fatty acids were dissolved in the aprotic solvents, namely 2-pyrrolidone (PYR), N-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO). As fatty acid concentrations in binary mixtures increased, surface tension and contact angle became diminished except where DMSO was used as a solvent. The longer chain of fatty acid, the lower the surface tension except when C_14-16 fatty acid was dissolved in NMP. Contact angle was also decreased as the chain of fatty acid increased except for C_14-16 fatty acid-based preparation due to their viscosity. Understanding these fatty acid solution's surface tension/contact angle behaviors is useful for designing the suitable fatty acid-based in situ forming system.

Abstract: Currently the measurement of surface texture in mechanical engineering is traditionally carried out using profilometers. Modern profilometers do not allow measuring of surfaces with complex shapes. This is due to the different sensitivity of the sensor and the discreteness of the movements along the axes of the Cartesian coordinate system. Coordinate Measuring Machines are devoid of such a drawback. However, stylus of the coordinate measuring machine has a diameter many times larger than the diamond stylus of the profilometer. Therefore, there is a mechanical filtering effect, that affects the results of measuring the parameters of the surface texture. In this paper a mathematical model of the contact of the spherical stylus and a rough surface based on analytical geometry is proposed. Influence of the diameter of the spherical stylus on the maximum measurement errors of a amplitude parameters are investigated. Seven amplitude parameters Rp, Rv, Rz, Ra, Rq, Rsk, Rku of the surface texture are modeled. Coordinate measuring machine and profilometer with stylus diameter of 2 μm measurement results are compared. it was concluded that the stylus diameter of the coordinate measuring machine when measuring the surface texture should be no more than 20 μm.

Abstract: The article presents the results of studies of the surfaces of parts processed by the contactless method of laser polishing. The results of technological surface treatment using a laser technological complex based on an ytterbium fibre laser with a power of 5 kW are presented. The results of studies of the surface roughness of the samples after laser treatment, including the non-uniform character due to the redistribution of the liquid metal melt over the surface, are shown. Requirements for metrological support of additive technology have been developed using the example of the process of laser remelting in order to improve quality and further automation.

Abstract: Among the many different ways to improve the performance of molds for injection molding, there are those that are based on the application of thin multi-layer wear-resistant coatings by cathode-ion bombardment. However, due to the relatively small thickness of the applied coatings, measuring their parameters is a difficult task. Therefore, the article considers methods for determining the main parameters of thin multilayer coatings, such as: microhardness, separation and crack resistance coefficients, Young's modulus. The results of measurements of several coatings of different compositions are presented.

Abstract: The publication outlines the issue of the experimental determination of modal parameters of structures using a method called operational modal analysis. The principle of the method and possible approaches of calculation of modal parameters are presented. An example of the method’s application is the determination of mode shapes and frequencies of the repaired footbridge in Kroměříž where the dynamic test was performed twice – before and after reinforcement of the structure. The results of both dynamic tests and their comparisons with the results of the calculation model performed in the ANSYS environment are presented in this article. Additionally, and integral to this article is a description of the completed footbridge reconstruction.

Abstract: This paper presents the methodology of designing a transducer for the experimental measurement of forces. For this purpose, an elastic element of the shape of the letter "S" is designed and manufactured. The elastic element designed in SolidWorks is subjected to virtual testing, using the finite element method in ANSYS. After validating the results obtained considering the maximum values ​​of the stresses that appear for the nominal load, the experimental model of the transducer is realized. The central part of the elastic element behaves like a fixed double beam subjected to bend by the measuring force. On this beam are bonded strain gauge transducers, which measure the deformations produced by bending. The transducer is calibrated, in order to obtain the calibration constant, based on the obtained characteristic, that is, the dependence of the specific strain-deformation and force. The transducer thus constructed can be used in force measurement applications.