Measurement Science Research Papers - Academia.edu (original) (raw)

2025, 2024 9th International Conference on Signal and Image Processing (ICSIP)

Electrocardiography (ECG) is a promising approach for continuous fetal heart rate monitoring. Its morphology can provide information on fetal health to guide patient care by clinicians. However, fetal ECGs extracted from abdominal ECGs are often too weak to reliably detect fetal heart rate. This study evaluates the application of a U-Net architecture for accurate R-peak detection in low-SNR fetal ECG signals. The proposed method achieves high accuracy with a positive predictive value of 99.81%, sensitivity of 100.00%, and an F1-score of 99.91% on direct fetal ECG from the Abdominal and Direct ECG Database, with significantly reduced false predictions, and outperforming two other baseline methods compared with. Notably, our approach demonstrates robustness, accurately predicting peaks in regions of high distortion, a capability unmatched by other methods evaluated. This finding indicates the suitability and benefits of the U-Net architecture for peak detection in fetal ECG signals.

2025, Measurement Science Review

The aim of our study was to develop a multimodal experimental protocol for in vivo imaging and metabolic parameters (MRI, DTI and 1 H MRS) in an animal model of neurodegeneration. We have successfully developed the protocol for simultaneous DTI/MRI/ 1 H MRS measurement to ensure unaltered conditions for repeatable non-invasive experiments. In this experiment, diffusion tensor imaging, spectroscopic and volumetric "bio-markers" were generated in the brain for the D-galactose model of "age-related dementia". The hippocampal relative volume, taurine and myo-inositol relative concentrations were found to be significant predictors contributing to the differences between the groups of rats treated with D-galactose in simulated "neurodegeneration", even in response to the applied Huperzine A therapy.

2025

This article describes the principle technique of passive and active thermography. In detail the more advanced technique of online heat flow measurements especially for the inspection of rotor blades are explained. Many examples show the possibility to detect defects like poor bonding, delaminations and internal structural faults by using passive techniques. But more advanced techniques like active online thermography will demonstrate the outstanding results in finding even small defects in these up to 65 m long rotor blades of wind turbines.

2025

Surface electromyogram (SEMG) is an indicator of the underlying muscle activity and can be useful for human control interface. One difficulty in the use of SEMG for identifying complex movements is the mixing of muscle activity from other muscles, referred to cross-talk. Similarity in frequency and time domain makes the separation of muscle activity from different muscles extremely difficult. Independent Component Analysis (ICA) is a useful technique for blind source separation. This paper reports investigations to test the effectiveness of using ICA for such applications. It determines the impact of different conditions on the reliability of the separation. The paper reports the evaluation of issues related to the properties of the signals and number of sources. The paper also tests Zibulevsky's method of temporal plotting to identify number of independent sources in SEMG recordings. The results demonstrate that ICA is suitable for SEMG signals when the numbers of sources are not greater than the number of recordings. The inability of the system to identify the correct order and magnitude of the signals is also discussed. It is observed that even when muscle contraction is minimal, and signal is filtered using wavelets and band pass filters, Zibulevsky's sparse decomposition technique does not identify number of independent sources.

2025

There is an urgent need for establishing a simple yet robust system that can be used to identify hand actions and gestures for machine and computer control. Researchers have reported the use of multi-channel electromyogram (EMG) to determine the hand actions and gestures. The limitation of the earlier works is that the systems are suitable for gross actions, and when there is one prime-mover muscle involved. This paper reports overcoming the difficulty by using independent component analysis to separate muscle activity from different muscles and classified using backpropogation neural networks. The system is tested and found to be effective in classifying EMG.

2025, Automatika ‒ Journal for Control, Measurement, Electronics, Computing and Communications

The aim of this study is to develop a new, computationally-efficient, anatomically-realistic 3D bidomain cardiac electrical activity model using widely available software and standard low-cost hardware. The model incorporates whole-heart embedded in a human torso, spontaneous activation of sinoatrial node and specialized conduction system with heterogeneous action potential morphologies. The model is capable of generating realistic body surface electrocardiograms (ECGs) and is proposed as a useful tool for investigating some major issues in heart pathophysiology and in stimulation; such as simulating and optimizing synchronized electrical cardioversion, defibrillation and pacing stimulation.

2025, Measurement Science Review

The aim of this study was the development of a geometrically simple and highly computationally-efficient two dimensional (2D) biophysical model of whole heart electrical activity, incorporating spontaneous activation of the sinoatrial node (SAN), the specialized conduction system, and realistic surface ECG morphology computed on the torso. The FitzHugh-Nagumo (FHN) equations were incorporated into a bidomain finite element model of cardiac electrical activity, which was comprised of a simplified geometry of the whole heart with the blood cavities, the lungs and the torso as an extracellular volume conductor. To model the ECG, we placed four electrodes on the surface of the torso to simulate three Einthoven leads VI, VII and VIII from the standard 12-lead system. The 2D model was able to reconstruct ECG morphology on the torso from action potentials generated at various regions of the heart, including the sinoatrial node, atria, atrioventricular node, His bundle, bundle branches, Pur...

2025, Measurement Science Review

Since the 1960s, Nb-Ti, exhibiting a superconducting transition temperature Tc of 9K, and Nb 3 Sn, with a Tc of 18K have been the materials of choice for superconducting applications. The prospects for the future changed dramatically with the discovery of ceramic high temperature superconductors exhibiting Tc values well above the boiling temperature of liquid nitrogen (77K). These materials are now widely considered for large power applications, electronics and magnets including a.o. power transmission cables, motors, generators, fault current limiters, transformers, NMR and MRI. The fabrication of useful conductors out of these layered cuprates encountered some problems in areas such as chemical and structural purity, stability, oxygen stoichiometry and weak links. However, a first generation of silver sheathed composites based on Bi 2- x Pb x Sr 2 Ca 2 Cu 3 O 10 has already been commercialised. It is now a widespread view that superconducting wires with high performance under strong magnetic fields and at elevated temperatures above liquid nitrogen, will need to be realised using the (RE)Ba 2 Cu 3 O y materials. Because of the weak link nature of these materials, a second generation of biaxially aligned coated conductors was developed. As a consequence, many deposition techniques have been studied to grow thin films of the superconducting (RE)Ba 2 Cu 3 O y and adequate buffer layers on suitably prepared textured substrates. In this paper, the critical parameters in the deposition of thin films using vacuum and non-vacuum techniques will be reviewed. Finally, this review will address the measurement of the obtained properties of these coated conductors. The most important practical characteristic of a superconductor is its critical current density. Spectroscopic methods such as I.R. play an important role in the development of adequate precursors for chemical solution deposition of thin films. Finally, microstructural analysis using XRD, SEM and TEM is important to reveal the relation of these features on the transport properties of the films.

2025

the continuous guidance and support I have received from him during this work. He was there with his kind help and direction anytime I needed them. His inspiration, motivation and friendly attitude helped make my work under him a great experience. Desire and ambition to emulate his knowledge and expertise in the field of research have also acted as a motivation to carry through my work. It was a great pleasure to be a part of his research group and work under him. I would also like to express my appreciation to the members of my thesis committee, Dr.

2025, Autex Research Journal

Flex fatigue behaviour of plastic optical fibres (POFs) with the diameters of 0.2 and 0.3 mm under different pretensions is measured with fatigue life curve by flexometer. The fatigue sensitivity coefficient is calculated by the linear fitting curve of normalised stress versus logarithm of bending cycles. The residual modulus is investigated during the flex fatigue processes. The results exhibit the exponential relationship between applied pretension and numbers of bending cycles at break. It is indicated that the flex fatigue of POFs might be sensitive with high swing angle or swing speed. There is an evident loss of modulus for two POFs with pretensions of 4 and 10% of ultimate tensile strength during 10-times bending cycles. The values of residual modulus of two POFs almost keep constant after 10-times bending cycles.

2025, MM Science Journal

Unconventional machining methods, or also progressive machining methods, such as laser cutting, waterjet cutting, ultrasound machining, etc. are undergoing a very rapid development. Laser cutting machines often evaluate even 80 parameters in real time. Their advantage is the significantly higher productivity. Many values are defined by the machine manufacturer and can not be changed for a given laser. For custom laser cutting there are 2 essential parameters, adjustable depending on the process gas employed. The aim of this article is to find the setting that will reduce the consumption of process media while maintaining or improving the quality of the machined surface.

2025

This paper describes the application of a monopole sensor to determine the moisture content in the tuber of Dioscorea hispida, based on magnitude and phase of reflection coefficient and admittance measurement. This preliminary work is to study relationship between microwave and alkaloid dioscorine of the tuber of Dioscorea hispida. The most widely used standard technique, which is the standard oven drying method, is time consuming and only suitable for laboratory experiment. As an alternative, measurement of moisture content in the tuber of Dioscorea hispida using microwave techniques is proposed. The measurement setup consists of a monopole antenna and a FieldFox RF Analyzer N9912A. This system utilizes a monopole sensor to transmit the microwave signal in the tuber of Dioscorea hispida sample and display the magnitude and phase of the reflection coefficient on the FieldFox. The admittance, on the other hand, is derived from the reflection coefficient measurement. The relationship ...

2025, Statistika: Statistics and Economy Journal

One of the approaches for forecasting future values of a time series or unknown spatial data is kriging. The main objective of the paper is to introduce a general scheme of kriging in forecasting econometric time series using a family of linear regression time series models (shortly named as FDSLRM) which apply regression not only to a trend but also to a random component of the observed time series. Simultaneously performing a Monte Carlo simulation study with a real electricity consumption dataset in the R computational langure and environment, we investigate the well-known problem of "negative" estimates of variance components when kriging predictions fail. Our following theoretical analysis, including also the modern apparatus of advanced multivariate statistics, gives us the formulation and proof of a general theorem about the explicit form of moments (up to sixth order) for a Gaussian time series observation. This result provides a basis for further theoretical and c...

2025, Open Science Framework

The development of Recursive Collapse Field Theory (RCFT) and the Unified Language of Recursive Collapse (ULRC) is informed by a long lineage of work at the intersection of mathematics, physics, symbolic systems, neuroscience, and philosophy. This article stands on the shoulders of foundational thinkers in nonlinear dynamics, information theory, memory research, and symbolic logic-whose contributions have shaped our understanding of recursion, entropy, and return. RCFT/ULRC is presented as a closed, independently derived system, constructed to unify symbolic mathematics and empirical reality in a manner that is both transparent and reproducible. The author gratefully acknowledges the broader intellectual community whose rigorous discourse, debate, and open exchange have made this synthesis possible. All equations, protocols, and theoretical advances herein are released to support the ongoing evolution of empirical science and to invite constructive engagement from all disciplines.

2025

This study evaluates the contribution of individual organs to the Body Surface Potential Map (BSPM) generated during ventricular activation. The human torso was modeled as an inhomogeneous volume conductor using CT data, and the heart was treated as an anisotropic volume source based on Diffusion Tensor Imaging (DTI). The ventricular conduction system was also extracted from DTI scans. Excitation propagation was simulated using the Monodomain Reaction-Diffusion Equation (MD-RDE), and the resulting BSPM was computed. By selectively removing specific organs from the torso model and comparing BSPMs using correlation coefficient and relative error metrics, the study identifies the relative influence of each organ. Results confirm that the blood volume within the ventricles has the greatest impact on BSPM accuracy, with the bones, lungs, and liver having lesser but measurable effects.

2025, Measurement Science Review

A dynamic thermomechanical analysis (D-TMA) apparatus is described for measuring the resonant frequency of the flexural vibration and the internal damping of the sample using the impulse excitation technique (IET). Since the measurement is conducted at temperatures up to 1250 °C, an electromagnetic impulser is used for excitation. The free vibrations are registered by an electret microphone, stored and then converted into a frequency spectrum using the fast Fourier transform, from which the resonant frequency can be found. The furnace is built from refractory porous alumina bricks and alumina fiber pads. The heating elements are four SiC rods connected to a temperature controller. The temperature is measured with a Pt-PtRh10 thermocouple in close proximity to the sample.

2025

This follow-up research expands on the initial piezoelectric energy harvesting system by introducing a systematic evaluation of efficiency, mechanical design, material robustness, and power electronics optimization. Although the original prototype proved feasibility under footstep loads, this study addresses critical gaps, such as controlled mechanical input, energy conversion efficiency, and real-world integration. Through experimental setups using programmable impact rigs, impedance-matched converters, and comparative material studies, the proposed system achieves a 320% increase in power output per unit volume while enhancing scalability and durability. This work aims to position piezoelectric harvesting as a viable contributor to self-powered electronics and hybrid micro-energy stations.

2025, Measurement Science Review

This paper describes the result of work performed at the Laboratoire National de Métrologie et d'Essais (LNE) aiming at developing a standard system to measure RMS value and harmonic contents of distorted voltage waveforms by means of a sampling voltmeter. Thermal converters are used to trace the RMS value to the SI units. The error of the DVM has been generally found less than 10 µV/V up to 2 kHz but can reach about 50 µV/V at 2.5 kHz for RMS voltage measurements for sine waves. For distorted waveforms, deviations within 15 µV/V have been obtained whatever the total harmonic distortion of the waveforms.

2025

Factor is one of the important parameters in fracture mechanics. One of the common geometries in evaluating of fracture mechanics problems is contact of tilted wedge with half plane that in this article Unsymmetrical tilted wedge geometry has been studied and digital Shearography as a non-destructive technique is applied to determine mixed mode stress intensity factors in a half plane with vertical edge crack which is subjected to an unsymmetrical tilted wedge. Optical setup with two in-plane illumination source is used to determine purposed strain variable and consequently obtain the mixed mode stress intensity factors as a result of applying linear elastic fracture mechanics (LEFM). The results of Shearography technique contains some fringes which contain the information needed to obtain the strain variables. To utilize the advantage of whole field Shearography and to minimize random experimental errors, the least square method is used to obtain SIF. In order to verify the obtained results accuracy, the experimental results were compared with the results of finite element method. The difference between two results is nearly 19%. The comparison of the experimental results and the numerical results proves the credibility and potential of this nondestructive method in measurement applications. Then the effect of crack size and gap of tilted wedge from crack tip on Stress Intensity Factors have been investigated. Finally it shown that in this problem Stress Intensity Factor in first mode of fracture is zero, so only second mode of fracture should be considered.

2025, Measurement Science Review

The wind turbine blade design is important in obtaining an effective wind turbine. In the field of wind energy, it is essential to understand the design and parameters affecting the blades of the wind turbine in order to obtain a successful design. However, most of the parameters are dependent on each other and this makes the design of wind turbines a challenging task. This research paper used the QBlade software to analyze and optimize the behavior of the small horizontal axis wind turbine. The software applies the Blade Element Momentum Theory (BEM) to study the wind turbine blades by calculating the drag and lift coefficients which were achieved by dividing the blades into 10 ascending segments. The twist angle and chord length of the blade are optimized to get the highest performance. Among the various airfoil types, the SG-6041 airfoil type was selected to build the blade structure. The calculated power coefficient was almost 0.4, which is considered high given that it was calc...

2025, Measurement Science Review

This paper presents an approach to estimate the orientation of the rectangular defect in the ferromagnetic specimen using the magnetic flux leakage technique. Three components of the magnetic flux leakage profile, such as radial, axial, and tangential component are considered to estimate the orientation of the rectangular defect. The orientation of the rectangular defect is estimated by the proposed analytical model using MATLAB software. The results calculated by the analytical model are validated by the three-dimensional finite element analysis using COMSOL Multiphysics software. Tangential component provides better performance to estimate the orientation of the rectangular defect compared with radial and axial component of the magnetic flux leakage profile.

2025

Epilepsy is a neurological condition that is found in most people all over the world, and the ability to accurately anticipate seizures in epileptic patients has a significant impact on both their level of protection and their overall quality of life. This research proposes a unique patient-specific seizure prediction approach based on Deep Learning (DL) using longterm scalp electroencephalogram (EEG) recordings to predict seizure onset. Preictal brain states should be adequately detected and differentiated from the prevalent interictal brain states as early as possible to make this technology acceptable for real-time use. A single automated system has been designed for the Features Extraction (FE) and classification processes. The raw EEG signal that has not been pre-processed is considered the input to the system, and the signal is further reduced using subsequent computations. An innovative reconstruction approach using Variational Auto-Encoder Generative Adversarial Networks (VAE+C+GAN) with the Cramer Distance (CD) and a Temporal-Spatial-Frequency (TSF) loss function is presented in this research work. The machine that discriminates receives instructions to differentiate between created tests and actual samples, while the generator is verified to produce false samples that the discriminator does not recognize as fake. The proposed VAE+C+GAN's experimental results have been examined, and a classification accuracy of 95% has been achieved. According to the experiment's findings, the VAE-C-GAN performs better than the current EEG classification system and has excellent potential for real-time applications.

2025

Sensor’s networks and information technology known at present an intensive development due to their numerous applications in car industry, aeronautics, telephony, computing and so on. To embark these systems in a large scale it is necessary for them, to be completely autonomous from an energy point of view. Vibration Energy Harvesting is a key point for powering sensor nodes, towards the development of autonomous sensor systems. To generate electrical energy three transduction mechanisms piezoelectric, electrostatic and electromagnetic are used. A comprehensive review of existing piezoelectric generators is presented including resonant, impact coupled and human based devices for micro power utilization. Electromagnetic generators employ electromagnetic induction arising from the relative motion between a conductor and a magnetic flux gradient. Electromagnetic generators presented in the literature are reviewed including wafer-scale integrated versions and large scale discrete device...

2025, Measurement Science and Technology

The resonant-mirror technique makes it possible to measure very small chemically induced changes in the refractive index of a surface layer. These small changes in refractive index can be masked by small changes in the temperature of the... more

2025, Measurement Science and Technology

The use of caged dye photo-activated fluorophore velocimetry is described and representative examples are presented. After a brief survey of recently reported measurements, a more detailed example of the flow produced in a cylinder with a single rotating end wall is presented. Simultaneous stereoscopic image sets in the (r, z) and (r, θ ) planes have been obtained over a Reynolds number range of roughly 10 2 -10 5 . At low Reynolds numbers ( 0-2000), the steady, axisymmetrical flow is found to quantitatively agree with predictions from a numerical flow solver. At higher Reynolds numbers (from 5 × 10 3 to 10 5 ), the flow develops considerable turbulent three-dimensional structure.

2025, Measurement Science Review

This paper describes instrumental measurement uncertainties and their influence on the result obtained from determination of rock sample uniaxial compressive strength and deformability. The interdependence of uncertainty contribution is analyzed and guides for improving measurement uncertainty are given. The achieved uncertainties are compared to typical uncertainties in the determination of concrete and metallic material compressive strength and deformability.

2025, Measurement Science Review

This paper presents the virtual instrument for measurement and determination of uniaxial compression strength and rock sample deformability. It analyzes properties and limitations of several implemented virtual instruments. Furthermore,... more

2025

The high temperature regions occurred along the cable limit the transmittable load capacity in power cables. The strains generated on XLPE insulation of a power cable shorten the cable operation time due to their ageing effects on insulation. Therefore it is clear that detecting the ‘hot spots’ and strain information along the cable is important. In this study, temperature and strain data have been obtained along a 380 kV power cable by using a 1550 nm single mode fiber. To detect temperature data along the cable, distributed temperature detection method based on Raman scattering has been used. In order to obtain strain data, Brillouin frequency shift information of the backscattered signal at the scattering point has been utilized. Under the occurrence of simulation conditions such as cable connection points, cross-connection points and passing through ducts, temperature and strain profiles have been obtained along a 5 km cable. Simulations have been performed with a spatial resolu...

2025, Measurement Science and Technology

This paper introduces an approach combining visual-based simultaneous localization and mapping (V-SLAM) and global positioning system (GPS) correction for accurate multi-sensor localization of an outdoor mobile robot in geo-referenced maps. The proposed framework combines two extended Kalman filters (EKF); the first one, referred to as the integration filter, is dedicated to the improvement of the GPS localization based on data from an inertial navigation system and wheels' encoders. The second EKF implements the V-SLAM process. The linear and angular velocities in the dynamic model of the V-SLAM EKF filter are given by the GPS/INS/Encoders integration filter. On the other hand, the output of the V-SLAM EKF filter is used to update the dynamics estimation in the integration filter and therefore the geo-referenced localization. This solution increases the accuracy and the robustness of the positioning during GPS outage and allows SLAM in less featured environments.

2025, Measurement Science and Technology

Two frequency Planar Doppler Velocimetry (2-PDV) is used in conjunction with imaging fibre bundles to make time-averaged three component velocity measurements using a single CCD camera and iodine cell. In this scheme the flow is sequentially illuminated with two different frequencies of laser light, which are separated by approximately 700MHz to 1GHz. Images are captured for each illumination frequency on a CCD camera viewing through an iodine absorption filter. These images are then used to produce a normalised transmission image that can be processed as in normal PDV. Three component measurements are made possible by porting separate views to a single CCD camera using the imaging fibre bundles. Results are presented here for a 2-PDV system demonstrated making time-averaged velocity measurements on a rotating disc and a seeded air jet.

2025, Measurement Science and Technology

Surrounding a long period grating, fabricated in a standard optical fibre, with a material with a high thermo-optic coefficient enhances the temperature sensitivity of a long period grating. Temperature sensitivities as high as 19nm/°C are reported over a temperature range of 1.1°. The temperatures at which the LPG exhibits enhanced sensitivity may be tailored by a suitable choice of material.

2025, Measurement Science and Technology

Shearography is a full-field speckle interferometric technique used to determine surface displacement derivatives. For an interferometric technique, shearography is particularly resilient to environmental disturbances and has hence become an invaluable measurement tool outside of the optics laboratory. Furthermore, the inclusion of additional measurement channels has turned shearography from a qualitative inspection tool into a system suitable for quantitative surface strain measurement. In this review article we present a comprehensive overview of the technique, describing the principle of operation, optical configurations, image processing algorithms and applications, with a focus on more recent technological advances.

2025, BP International: Science and Technology: Development and Applicationsd

Blood pressure (BP) variability depicts the dynamic and continuous variations that occur in blood pressure levels over a period of time. This variability includes a wide range of BP variations, occurring over seconds or minutes (short-term variability), or over 24 hours (long-term variability). Blood pressure variability has been observed as a predictor of cardiovascular outcome. Accurate Blood Pressure measurement is vital in the prevention and treatment of cardiovascular disease. The observed correlation between as pulse arrival time and BP has led to the development of a wearable data acquisition device for BPV (Blood pressure variability) monitor, which was briefly described in this paper. While intravenous blood pressure monitoring remains the gold standard for assessing BPV, a noninvasive alternative-beat-to-beat monitoring by Finapres-is widely used. The advent of Wearable technology has gained momentum in recent times. The population has become user-friendly with such devices. Exorbitant cost of Finapres, ready availability of wearable sensors and adequate correlation of beat-to-beat blood pressure with pulse arrival time and pulse transit time have led to the development of inexpensive hardware for blood pressure variability monitoring. Pulse Arrival Time variability is observed to be consistent with past observations reported in the literature. To take care of the noise in the spectrum, Pulse Transit Time variability is being worked out. This development employing AD8232, MAX30102, TCA9548A and Arduino Uno is briefly described in this paper. Blood pressure variability, measured using PAT along with heart rate variability, was analyzed in eight control subjects and four hypertensive subjects. PAT variability had evident VLF, LF, and HF peaks in the control subjects, which Science and Technology: Developments and Applications Vol. 8 Development of a Low-Cost Wearable Device for Blood Pressure Variability Monitoring Using Pulse Arrival Time 111 mirrored the patterns noted in HRV variability. However, in the hypertensive subjects, no LF and HF components were present in HRV variability, while VLF and LF were absent in PAT variability. These findings are consistent with what has been previously reported in regard to blood pressure variability.

2025, Measurement Science Review

The aim of this paper is to determine inter-reliability, concurrent validity, and interchangeability of the SMS HG dynamometric system and a Jamar digital dynamometer for hand grip strength measurements performed in two relevant positions of the elbow joint, i.e. 90 o flexion and 180 o (full) extension. The sample in this research consisted of 61 participants and included 27 women and 34 men. Statistically significant differences in the results found between two positions in the elbow joint indicate that the results must be evaluated separately. However, regarding both testing positions, i.e. 90 o flexion and 180 o extension in the elbow joint, it was determined that SMS HG and Jamar instruments have a very high level of inter-reliability (ICC 0.948 to 0.980), but lack concurrent validity. The established mean difference of the results was higher for the 90 o than for the 180 o position but in both cases was considered to have a practical significance, thus not supporting the interchangeability of the instruments.

2025

Článok stručne opisuje experimentov zameraných na overenie vybraných technologických parametrov plazmového rezacieho stroja. Konštrukčné riešenie tohto stroja predstavuje komplexnú kinematickú štruktúru s deviatimi stupňami voľnosti. Jedným z najdôležitejších parametrov, ktoré sa od stroja požadujú, je dosiahnutie predpísanej opakovanej presnosti polohovania. Úplný návrh experimentov si vyžaduje viac ako tisíc experimentov. preto sa pripravil redukovaný návrh experimentov, ktorý s vyžaduje vykonanie iba 32 experimentov. Predpokladáme pritom iba jedno opakovanie každého experimentu. Ak sa má sledovať aj rozptyl nameraných údajov, vyžaduje sa najmenej päť opakovaní každého experimentu, čo vedie k značnému nárastu ich počtu.Paper briefly describes design of experiments aimed at verification of selected technological parameters of the plasma cutting machine. Design solution of the plasma cutting machine represents a complex kinematic structure with 9 DOF. Reaching the prescribed repeate...

2025, Measurement Science Review

The paper presents a matrix approach to the propagation of uncertainties in the realization of the ITS-90 using Standard Platinum Resistance Thermometers (SPRT) calibrated at Defining Fixed Points (DFPs). The procedure allows correlations to be included between SPRT resistances measured during the calibration at the DFPs (i.e., the realization of the ITS-90) and the resistances measured during the subsequent use of the SPRT to measure temperature T 90. The example also shows the possible contribution of these correlations to the overall temperature uncertainty measured by a calibrated SPRT.

2025, Measurement Science Review

Modern production machines employ complex kinematic structures that shall enhance their performance. As those machines are very sophisticated electro-mechanical structures, their design is time consuming and financially demanding. Therefore, designers search for new possibilities how to estimate future properties of the machine as early as in the design phase. The paper gives a brief introduction to the adoption of methodology of measurement uncertainties into the design of production machines. The adapted methodology enables to estimate the theoretical positioning accuracy of the machine end effector that is one of the important indicators of machine performance. Both serial and parallel kinematic structures are considered in the paper. Methodology and sample calculations of theoretical positioning accuracy are presented for serial kinematic structure (represented by advanced plasma cutting head) and parallel kinematic structure, represented by one specific design named Tricept.

2025

The paper deals with machines employing parallel-kinematics structures (PKS). They represent a relatively new generation of machine tools. Depending on the number of struts, the machines are referred to as hexapod or tripod machines. Such machines offer several advantages comparing to the conventional machine tools with serial kinematics, such as high flexibility, high stiffness, and high accuracy. It is very suitable for High- Speed-Machining (HSM), light machining and has received a wide interesting in manufacture industry. To achieve a desired positioning accuracy and stability, the static and dynamic properties of the machine must be searched and mathematically described. The calculation of the estimate of positioning deviation, including respective uncertainty and covariances, is much more complicated task comparing to the serial kinematics.

2025

This research deals with the energy harvesting issues of a piezoelectric harvester under magnetic excitation. Following the determination of dynamic equations of the system the remaining part of the paper presents the experimental findings. The system is characterized by the magnetic field excitation frequency f, distance from the electromagnet tip to equilibrium point of harvester d, and amplitude of the magnetic field strength (i.e. electromagnet voltage). The experimental data of displacement, velocity and voltage outputs are used via a data acquisition card in the cases of different parameters. According to the results, the harvested power strictly depends on f, and the total harmonic distortion (THD) as a tool for the determination of complexity indicates a substantial increment at low power cases. Apart from some previous studies, it is proven that nonlinear vibrations decrease the output power under changeable magnetic excitation.

2025, Measurement Science Review

2025

Imaging methods are applied in engineering and experimental mechanics areas to measure strain fields. The SPOTS project tackles the problem of traceability in optical strain measurement. Strain, being a displacement derivative, is a measurement quantity derived from the base unit length. We outline routes for traceability of optical strain measurement values, and underline the role of measurement standards for strain. Measurement uncertainty for calibration of an ESPI interferometer is detailed.

2025

Guided wave based inspection and monitoring systems for railway tracks operate at frequencies where as many as 40 modes of propagation may exist. During the development of such systems it is advantageous to be able to measure the amplitude of the individual modes of propagation. The availability of scanning laser vibrometer systems has made it possible to measure the displacement or velocity at a large number of points on the rail surface. The contribution of each mode of propagation may be estimated from the measured frequency responses by using a pseudo-inverse technique and mode shape information computed from a semi-analytical finite element model. Scanning laser measurements were performed in the field at distances of 10m and 500m from a transducer used to transmit the guided waves. A scan of 430 measurement points was used to measure 25 modes at 40kHz.

2025

A national traceability in force measurement to the Regional Reference Standards Laboratory (Department of Legal Metrology) without much degradation in the uncertainty while transferring the unit from the National standards to the user is achieved by developing and commissioning a dead weight force machine of 50 kN capacity at Regional Reference Standards Laboratory (RRSL), Bangalore and 50 kN comparator type force machines at other (RRSLs located at different parts of India. The established standard machines are directly compared for their performance through an artifact calibrated against the NPL primary standard machine having a BMC of ± 0.003 % (k=2). The load cell calibration data obtained from the different machines show that the realized force is found to be within ± 0.05% and hence the performance of the established force standard machines is highly satisfactory.

2025, DOAJ (DOAJ: Directory of Open Access Journals)

The article describes possibility of the deformity magnetic field numerical modeling into surroundings of the measured dia -paramagnetic specimens. This deformation study is given for the purposes MR measuring, where MR images are deformed from the point of view of susceptibility heterogeneous materials. For the numerical simulation was chosen elementary configuration. The results was verified by MR experimental measurement. As the MR measurement method was used techniques of the gradient echo

2025, Measurement Science Review

The widespread use of magnetic resonance (MR) techniques in clinical practice, and recent discovery of biogenic ferrimagnetic substances in human tissue, open new questions regarding health hazards and MR. Current studies are restricted just to the induction of Faraday currents and consequent thermal effects, or 'inoffensive' interaction with static magnetic field. We outlined that magnetic energies associated with interaction of ferrimagnetic particles and MR magnetic fields can be dangerous for sensitive tissues like the human brain is. To simulate the interaction mechanism we use our 'Cube' model approach, which allows more realistic calculation of the particle's magnetic moments. Biogenic magnetite nanoparticles face during MR examination three principal fields: (i) main B 0 field, (ii) gradient field, and (iii) B 1 field. Interaction energy of biogenic magnetite nanoparticle with static magnetic field B 0 exceeds the covalent bond energy 5 times for particles from 4 nm up to 150 nm. Translation energy in gradient field exceeds biochemical bond energy for particles bigger than 50 nm. Biochemical bond disruption and particle release to the tissue environment, in the presence of all MR fields, are the most critical points of this interaction. And together with relaxation processes after application of RF pulses, they make biogenic magnetite nanoparticles a potential MR health hazard issue.

2025, Measurement Science Review

The article focuses on the analysis of the possibilities to model motion and dispersion of plumes of different density gas pollutants in lowspeed wind tunnels based on the application of physical similarity criteria, in this case the Froude number. The analysis of the physical nature of the modeled process by the Froude number is focused on the influence of air flow velocity, gas pollutant density and model scale. This gives an idea of limitations for this type of physical experiments in relation to the modeled real phenomena. The resulting statements and logical links are exemplified by a CFD numerical simulation of a given task calculated in ANSYS Fluent software.

2025, Journal of Nondestructive Evaluation

Laser shearography is a powerful optical tool that is able to directly measure the displacement derivatives using interferometric effects. Stroboscopic shearography provides a full field, reliable and repeatable inspection process that facilitates defect visualization. The aim of this paper is to investigate the effectiveness of laser shearography for inspection of a large aluminum plate with a large wall thinning. A modified Michelson interferometer is introduced in order to inspect the entire aluminum plate simultaneously. The wall thinning is visualized as the region of the anomaly in the quasi-uniform and homologous shearography fringe pattern. The boundaries of the wall thinning cannot be indicated precisely due to the nature of the formation of shearography fringes. Therefore, the small shearing method is applied to determine the dimensions of the wall thinning. This approach allows for the detection of the wall thinning in the wider range of excitation frequencies. The wall thinning is successfully detected using the small shearing method as a light rectangle in the inconspicuous background. Finally, a novel averaging approach is proposed to eliminate the effects of noise and uncertainty in the calculation of the boundaries. Using this approach, the shearography interferometric effects are significantly reduced.

2025, The Review of scientific instruments

Nondestructive evaluation using shearography requires a way to stress the inspection target. This technique is able to directly measure the displacement gradient distribution on the object surface. Shearography visualizes the internal structural damages as the anomalous pattern in the shearograpic fringe pattern. A piezoelectric (PZT) excitation system is able to generate loadings in the vibrational, acoustic, and ultrasonic regimes. In this paper, we propose a PZT-excited stroboscopic shearography. The PZT excitation could generate vibrational loading, a stationary wavefield, and a nonstationary propagation wave to fulfill the external loading requirement of shearography. The sweeping of the PZT excitation frequency, the formation of a standing wave, and a small shearing to suppress the incident wave were powerful controllable tools to detect the defects. The sweeping of the PZT excitation frequency enabled us to determine one of the defect-sensitive frequencies almost in real time...

2025

Efficient lighting technologies are not necessarily less sensitive to voltage fluctuations than the incandescent lamp, and therefore a procedure for controlling the immunity of lamps to voltage fluctuations was defined in the IEC 61547 standard. This procedure checks that a lamp is not more sensitive than the incandescent lamp to voltage fluctuations corresponding to the P st = 1 curve. For a lamp that behaves linearly, these tests are sufficient to guarantee 1 that a lamp is less sensitive than the incandescent lamp at any voltage fluctuation level. This paper analyzes the linearity in the response of a set of lamps with both simulated and real voltage signals. For a given input voltage signal containing fluctuations, a new signal was generated with a voltage fluctuation whose amplitude was proportional to the original one. Both signals were passed through an illuminance flickermeter and the obtained flicker severity values were compared. The results showed that not all the lamps behaved linearly. Some lamps were less sensitive than the incandescent lamp at the reference level, and with other voltage fluctuation amplitudes produced flicker severity values higher than the incandescent lamp. Moreover, the nonlinearity shown with real voltage signals was not reflected with the same nonlinear behavior with simulated fluctuations in all cases. These results lead to the conclusion that the current immunity protocol is insufficient for guaranteeing that a lamp is less sensitive to voltage fluctuations than the incandescent lamp at every voltage fluctuation level.

2025, Renewable & Sustainable Energy Reviews

In recent years, several countries have adopted measures aimed at improving the efficiency of energy usage and reducing energy costs. One initiative has been to encourage the use of efficient lighting technologies by replacing inefficient lamps such as the incandescent lamp with more efficient lamps. However, this change can have consequences in terms of power quality, and more specifically in terms of flicker. The standardized procedure for flicker measurement is based on the working principle and characteristics of the incandescent