Marko Jurčević

Direct-current transformers (DCCTs) rely on small toroidal cores made of soft magnetic materials with high permeability, whose magnetic properties affect the sensitivity and linearity of the sensor. Reliable characterization of such small cores and of the resulting sensor component requires measurements with stated uncertainties, which are rarely reported together. This paper applies and integrates established measurement methods, namely, dynamic hysteresis loop measurements on ring specimens and dc current detection from the asymmetry of the saturation current peaks, into a laboratory test setup for the characterization of DCCT sensor components. Permalloy and nanocrystalline toroidal cores are characterized at 50 Hz. The nanocrystalline cores exhibit a maximum relative permeability of approximately 300 × 10³ and a coercivity of approximately 1.1 A/m, compared with approximately 100 × 10³ and 4.2–4.9 A/m for the permalloy cores. The sensor component with the tested core is calibrated against a reference current shunt for both current polarities, showing a linearity error of 0.59% FS in the range from −4 A to +4 A. The expanded uncertainty of the reference current measurement is ± 926 µA/A according to the GUM and ±906 µA/A using the Monte Carlo method (k = 2). The results show that the tested nanocrystalline cores are better suited for sensitive dc current detection and provide a basis for core selection and DCCT design.

This paper focuses on the application of non‐thermal Internet‐of‐Things (IoT) extraction of bioactive compounds from sugar beet leaves. High power ultrasound was used as a non‐thermal processing unit and was integrated with IoT hardware and software. In parallel, two other extraction methods were employed—thermal extraction and cold extraction. The bibliometric review showed that ultrasound extraction of sugar beet leaves has a research potential. Sugar beet leaves contain high levels of macronutrients, including sodium (9138.35 mg/kg), potassium (7275.87 mg/kg), calcium (6276.36 mg/kg), and magnesium (3612.79 mg/kg), as well as micronutrients such as zinc (39.63 mg/kg), manganese (51.85 mg/kg), copper (6.36 mg/kg), and boron (11.96 mg/kg). When it comes to extraction, the highest concentrations of amino acids were estimated for Glx ^b (193.00 and 134.41 μg/mL) in the ultrasound and thermal extracts. The ultrasound sample had a higher total polyphenol content (≈4.9 mg gallic acid equivalent/g d.m.) and total flavonoid content (≈6.1 mg quercetin eq./g d.m.) compared to the other two samples. The ultrasound method, applied within a non‐thermal IoT processing framework, resulted in higher concentrations of proteins. The highest concentration of the Ribulose bisphosphate carboxylase large chain peptides was obtained by the ultrasound and cold extraction procedures.

The increasing adoption of the Industrial Internet of Things (IIoT) has led to significant improvements in operational efficiency but has also brought new challenges for cybersecurity. To address these challenges, a number of standards have been introduced over the years. One of the best-known series of standards for this purpose is ISA/IEC 62443. This paper examines the applicability of the ISA/IEC 62443 series of standards, traditionally used for securing industrial automation and control systems, to the IIoT environment. For each requirement described in the ISA/IEC 62443 standards, relevant research on that subject is reviewed and presented in a table-like manner. Based on this table, areas for future research are identified, including system hardening, asset inventory, safety instrumented system isolation, risk assessment methodologies, change management systems, data storage security, and incident response procedures. The focus on future improvement is performed for the area of system hardening, for which research and guidelines already exist but not for the specific area of IIoT environments.

Phasor Measurement Units (PMUs) are being used extensively for electrical grid monitoring and control. However, their cost prohibits further adoption on the distribution grid and easy access for educational purposes. This paper proposes that simple and fundamental functions of a PMU can be achieved using an energy metering IC and integrated into smart electricity meters, providing a lower cost and more widely available method of monitoring and control of distribution grids, and presents a proof-of-concept platform with aforementioned functionality. The described platform's construction and flexibility emphasizes its educational capabilities PMUs and electricity meters as well.

Purpose: Clinical experience regarding the fluctuations of the refractive error of the eye during the different stages of Graves’ ophthalmopathy observed through outpatient clinic frequent check-ups points towards an underestimated and often overlooked problem. Published data about it are sparse. The clinical manifestations of Graves’ ophthalmopathy can be understood from the perspective of “compartment syndrome” and literature implies how such changes can affect the refractive error and consequently, the visual acuity. The purpose of the study was to explore how the clinical activity score of Graves’ ophthalmopathy affects refractive error and visual acuity. Patients and Methods: The study was prospective and observational, including 60 eyes of 30 patients with clinically active Graves’ ophthalmopathy. All the patients were monitored and evaluated over a period of 36 months by the clinical activity score, spherical equivalent and visual acuity. All the observed parameters were statistically analyzed. Results: The mean values of spherical equivalent and visual acuity throughout the observed period showed continuous fluctuation. Repeated measure analysis of variance showed statistically significant differences in visual acuity and spherical equivalent over the observed period. There was a statistically significant positive correlation between visual acuity and clinical activity score. The correlation between spherical equivalent and clinical activity score was also positive but not statistically significant. Conclusion: A decrease in the clinical activity score is either the result of a spontaneously resolving course of Graves’ ophthalmopathy or a consequence of treatment, so lowering in fluctuation of refractive error and improved visual acuity may be associated with a reduction in orbital inflammation.

Fitness and activity trackers are hugely popular wearable devices that monitor various health-related metrics, such as step count, heartbeat rate, or even oxygen saturation. Utilizing personal health information obtained by users’ personal trackers provides promising results in the fields of telemedicine and personal well-being. However, we face challenges such as data quality, privacy and compliance with standards and regulations. This paper addresses such challenges, with the focus on the last one. Semantic constraints for healthcare datatypes are defined to ensure compliance with standards, making the information medically valid and relevant. A process of semantic verification and Schematron-based validation is proposed. The validation process suggested in this paper will enable the data to be transferred and incorporated into a formal Electronic Health Record. The process is then verified using datasets containing various health-related data types. The aim is to integrate personal health data into Electronic Health Record, which forms a part of Central Health Information System. This would provide personalized medical services to patients and help physicians to make more informed decisions.

The paper presents an accurate and simple method for the approximation of the nonlinear B-H curves using expansion into complex exponential series. The least-squares fit of the model is obtained by the application of the Moore-Penrose pseudoinverse. Due to the completeness of the orthogonal basis of the approximation, any desired accuracy can be achieved with increasing the number of terms. Using the measurements acquired by an automated system based on the PXI digitizer boards, the feasibility of the method is proved.