Loading Phase Research Articles

Distributed Process Monitoring for Multiagent Systems Through Cognitive Learning

Multi-agent systems are usually large-scaled with a growing degree of intelligence and integration. Direct applications of traditional (centralized) methods will become incompetent for effective process monitoring of multi-agent systems. It necessitates the cognitive learning strategies that determine the effective interactions among subsystems or individuals. Therefore, in order to improve monitoring performance, this paper targets the development of a new distributed process monitoring method that has the cognitive learning ability by embedding an adaptive pickup rule. The proposed cognitive learning-based method can reduce the computation loads in both off-line and online phases because only necessary information exchange (or communication topology) is involved. Furthermore, the threshold used for system monitoring is obtained by developing a fast search algorithm based on statistical learning theory. Case studies on the wastewater treatment system, which can be regarded as a typical multi-agent system, demonstrate the superiority of the proposed distributed process-monitoring method.

Relationships between Patient-Reported Outcome Measures and Clinical Measures in Naïve Neovascular Age-Related Macular Degeneration Patients Treated with Intravitreal Ranibizumab.

Our objective was to evaluate changes in patient-reported outcome measures using the NEI-VFQ 25 questionnaire during a treat and extend regimen in naive neovascular Age-Related Macular Degeneration patients, and its correlation with anatomical and functional data. We conducted a prospective observational study. Patients underwent a treat and extend regimen with intravitreal ranibizumab for neovascular Age-Related Macular Degeneration. Initial response was evaluated at 4th month, and subsequently in every follow-up visit. If a clinical response was achieved, the injection interval was extended in two-week increments, up to a maximum of 12 weeks. Quality of life was assessed using the NEI-VFQ 25 questionnaire at baseline, 4th months, and 12th months. Patients were categorized as good or poor responders based on Best corrected visual acuity, central foveal thickness, intraretinal fluid, or subretinal fluid. Treatment with ranibizumab led to a significant improvement in quality of life, with a mean increase in NEI-VFQ 25 score of 4.27 points in the 12th month. No significant differences in improvement were observed between good and poor responders. Quality of life scores in neovascular Age-Related Macular Degeneration patients improved with intravitreal treatment regardless of the clinical response. The early response following the loading phase could indicate better quality of life after one year of treatment, with Best corrected visual acuity being the clinical parameter with the greatest influence on quality of life.

Choroidal remodeling following different anti-VEGF therapies in neovascular AMD

The purpose of this study was to investigate choroidal morphology remodeling in AMD-associated type 1 macular neovascularization using two different anti-VEGF drugs. We registered 73 treatment-naïve eyes with a diagnosis of exudative AMD and type 1 MNV. Patients received 3 monthly intravitreal aflibercept (n = 36, aflibercept group [AG]) or brolucizumab (n = 37, brolucizumab group [BG]). Baseline best-corrected visual acuity (BCVA) and anatomical (structural optical coherence tomography) parameters were collected at “T1 control”, before the loading phase (LP) of intravitreal injection, and at “T2 control”, 1 month after the last injection. The main outcomes measured were choroidal vascularity index (CVI), sub-foveal choroidal thickness (SFCT), and central macular thickness (CMT). Our results displayed significant SFCT reduction in both groups between T1 and T2 (p < 0.05), We did not find choroidal vascularity modifications (p > 0.05) after the loading aflibercept injections. Moreover, only the BG displayed a significant choroidal remodeling (stromal choroidal area [SCA], total choroidal area [TCA] and CVI) at T2 (p < 0.05). In particular, a relevant stromal and total choroidal volume reduction was noted, accompanied by an increase in CVI. To conclude, the latter modifications of the choroidal morphology were found significant between two groups (p < 0.05). Our analysis showed a significant impact of brolucizumab on choroidal morphology in eyes affected by type 1 nAMD. This effect was found relevant when compared with aflibercept.

Effect of polyp regression and reduction on treatment efficacy in polypoidal choroidal vasculopathy treated with aflibercept

Intravitreal injection of aflibercept (IVA) has successfully treated polypoidal choroidal vasculopathy (PCV), and polyp morphology is an important indicator of treatment efficacy. However, many studies have not reported the presence or absence of polyp regression and treatment outcomes, and few studies have reported polyp reduction and treatment outcomes in cases with residual polyps. We retrospectively measured the polyp area on indocyanine green angiography images before and after the IVA loading phase and investigated the regression and reduction of polyps and treatment outcomes of 81 eyes with PCV treated with IVA. We investigated the relationship between the presence or absence of complete regression of polyps and the percentage change in the polyp area and treatment outcomes. Eyes with complete polyp regression had significantly better visual acuity improvements compared with baseline at 12 months (P = 0.0108), fewer treatments (P = 0.0024), fewer recurrences during 12-months follow-up (P = 0.0010), and more “dry maculas” at 3 months (P = 0.0048) than eyes in which polyp regression did not occur. A significant correlation was seen only between the percentage of polyp regression and visual acuity at 3 months (P = 0.0395). Regarding IVA therapy for PCV, the presence or absence of complete polyp regression at the end of the loading phase affected the treatment outcome, whereas the degree of polyp reduction in cases of residual polyps had no effect.

One-year results of treat-and-extend regimen with intravitreal faricimab for treatment-naïve neovascular age-related macular degeneration.

To evaluate 1-year outcomes of loading phase treatment followed by maintenance therapy using a treat-and-extend (TAE) regimen with intravitreal faricimab for neovascular age-related macular degeneration (nAMD). Retrospective, interventional case series. We retrospectively studied 40 eyes of 38 consecutive patients with treatment-naïve nAMD, assessing best-corrected visual acuity (BCVA), foveal thickness, central choroidal thickness (CCT), total number of injections over 1 year, and intended injection interval at the last visit. Thirty eyes (75.0%) had completed the 1-year intravitreal faricimab treatment. Their BCVA showed significant improvement, with significant reductions in foveal thickness and CCT. The total number of injections during the 1-year treatment period was 6.6 ± 0.7. The intended injection interval at the last visit was 12.7 ± 3.3 weeks. Of the 10 eyes (25.0%) failing to complete the 1-year faricimab treatment, 1 eye developed intraocular inflammation after the loading phase treatment but showed no recurrence of exudative changes, and no further treatment was required. Moreover, 5 eyes switched to intravitreal brolucizumab injection due to persistent exudative changes with an 8-week interval of faricimab injections. The remaining 4 eyes either dropped out or the patient died. A loading phase treatment followed by a TAE regimen with intravitreal faricimab appears to be generally safe and effective for improving visual acuity and ameliorating exudative changes in eyes with nAMD. However, there might be cases in which exudative changes cannot be adequately controlled with injections of faricimab every 8 weeks in the maintenance phase.

Functional and anatomical outcomes of brolucizumab for nAMD in a real-life setting

To report long-term outcomes of brolucizumab in neovascular age-related macular degeneration (nAMD) treatment. Records from 74 patients were retrospectively reviewed. Both naïve eyes and those previously treated with other antiVEGF agents were included. Primary outcomes included variation in best corrected visual acuity (BCVA), central subfield thickness (CST), intraretinal fluid (IRF), subretinal fluid (SRF), and pigment epithelial detachment (PED) dimensions. Outcomes were reviewed after the loading phase, at week 24, and at last follow-up. IOI occurrence represented the secondary outcome. BCVA improved significantly in both groups. In switched eyes, IRF and SRF were significantly reduced at every timepoint, with CST reduction from week 24 (p = 0.005). In naïve group, CST decreased from the loading phase (p = 0.006) and all patients showed dry macula from week 24. A significant reduction in PED maximum high was demonstrated in both groups. In seven naïve eyes, PED completely reabsorbed; a slight increase in PED horizontal maximal diameter was also observed from week 24. IOI occurred in 5.4% of cases. In conclusion, brolucizumab showed a strong drying effect, permitting functional improvement together with fluid reabsorption and an encouraging modification of PED dimension, especially on naïve patients. These results together with the extension of treatment intervals make brolucizumab an efficient therapeutic strategy for nAMD.

Real-Time Data Acquisition and Monitoring of Three Phase Load Balance in Electricity Distribution

A real-time monitoring mechanism for three-phase electrical power distribution panels is essentially needed to ensure that the power is evenly distributed across all phases, so that the efficiency of energy usage could be maintained. This paper presents monitoring and data acquisition system for three-phase balance distribution. The system ensures balanced distribution of electrical power in order to enhance the efficiency and reliability of power systems. It leverages advanced technologies to collect, analyze, and report data, providing valuable insights into the performance of the power distribution network. Data acquisition is established by using sensor PZEM004T to measure the electricity parameters which is integrated with Arduino microcontroller. In addition, real-time monitoring system is visualized through dashboard data management for more informative data acquisition and analytic purposes. The performance is evaluated by testing the instrument and application at a distribution panel within a span of five days to monitor electrical parameters. The results show that real-time monitoring system for three phase balance works perfectly to provide actual data and phase balance condition. The phase imbalance values are higher during the peak working hours where the loads are dynamics and extensively used.

Allocation of power losses and energy in the distribution network

The goal is to determine methods for calculating power losses in a three-phase four-wire low voltage distribution network using measurements of a balance smart meter and consumer smart meters, and to establish the factors influencing the power losses and their allocation among individual network wires, loads, and consumers. The study involved examining three methods for determining power losses for current measurement snapshot. The first method suggests calculating losses as the difference between the power supplied to the network and the total power consumed. The second method calculates power losses using the contribution method. The third method, which in addition to measurement information requires knowledge of the topology and parameters of the network components, determines power losses based on the results of the state estimation method. The research proposes an algorithm for transition from a four-wire distribution network modeling to a three-wire one. The algorithm allocates power losses of the neutral wire among the phase wires. The findings indicate that the negative losses in the network with unbalanced phase loads are caused by the presence at the nodes of the least loaded phase of higher voltage than the voltage at the power supply node. The reason for higher losses in phases with minimal load is the uneven allocation of loads in the phases. In addition, the study reveals that the power loss values obtained by the contribution method, i.e. directly from the measurements of smart meters, are closer to the losses determined from the readings of the balance meter and consumer meters, compared to the losses found from the state estimation results. The considered methods for calculation and allocation of power losses are illustrated by an example of a real-world distribution network equipped with smart meters. The paper demonstrates the examples of allocating total power losses between phase wires and a neutral wire, among phase wires only, and between total loads at phase nodes and individual consumers in phases.

Effective magnetoelastic responses of hybrid fiber composites with viscoelastic matrices

This study examines the overall magnetoelastic responses of unidirectional fiber composites constructed by magnetostrictive fibers embedded in viscoelastic polymer matrices that had been reinforced by stiff fillers. In some polymer-based fiber composites, modifying polymer’s property by infiltrating particulate fillers is necessary. To design such hybrid composite systems with magnetoelastic coupling, it requires a detailed understanding of aggregate responses. In this study, we formulate a composite constitutive model based on a two-scale homogenization scheme for effective coupled viscoelastic and magnetoelastic responses for hybrid fiber composites. We first verify the validity of the model by comparing the predictions with experimental results available in literatures. We next investigate the performance of a hybrid composite in light of blocked stress and free strain which are two common factors of characterizing sensors and actuators. We finally elucidate how viscoelastic polymer matrices affect the overall magnetoelastic responses and ΔE-effect phenomenon in terms of some critical parameters such as phase concentrations, loading rates, prestresses and temperatures. The findings of this study serve as a preliminary guidance for the rational design of hybrid magnetostrictive composite materials. The proposed mathematics model can further integrate into a finite element framework for composite structure analysis.

European Unmet Needs in the Management of Neovascular Age-Related Macular Degeneration in Daily Practice: Data from the Fight Retinal Blindness! Registry

PurposeTo evaluate the proportion, predictors and outcomes of neovascular age-related macular degeneration (nAMD) patients treated with a high burden of vascular endothelial growth factor (VEGF) inhibitor injections (IVT) after two years in routine clinical practice. DesignRetrospective analysis of data from a prospectively designed observational outcomes registry, Fight Retinal Blindness! project, of patients treated in European centers. ParticipantsTreatment-naïve eyes (one eye per patient) starting VEGF inhibitors for nAMD from January 2017 to March 2020 with 24 months of follow-up. We analyzed three treatment burden groups defined by the mean interval of the three closest injections to the 24-month visit: (1) those with a high treatment burden had injection intervals ≤ 42 days, (2) those with a low treatment burden had injection intervals between 43 and 83 days and those with tolerable treatment burden had injection intervals between 84 and 365 days. MethodsMultinomial regression was used to evaluate baseline risk predictors of patients requiring a high treatment burden. Main Outcome MeasuresThe proportion of patients that experienced a high treatment burden at 2 years and its predictors. ResultsWe identified 2,038 eligible patients completing 2 years of treatment (2038/3943 patients [60%]) with a median (Q1, Q3) of 13 (10, 17) injections. The proportion of patients with a high treatment burden was 25% (516 patients) at 2 years. Younger patients (Odds ratio (OR), 0.97; 95%CI, 0.96-0.99; P<0.01) were more likely to have high treatment burden, while eyes with type 3 CNV at baseline were significantly less likely (OR, 0.26; 95%CI, 0.13-0.52; P<0.01). Regarding type of fluid, patients with subretinal fluid only at baseline (OR, 3.85; 95%CI, 1.34-11.01; P=0.01) and persistent active intraretinal (OR, 1.56; 95%CI, 1.18-2.06; P<0.01) or subretinal fluid only (OR, 2.21; 95%CI, 1.52-3.21; P<0.01) after the loading phase had a higher risk of high treatment burden at 2 years. ConclusionsHigh treatment burden is common issue in routine clinical practice in Europe, with a quarter of patients requiring injections of conventional VEGF inhibitors every 6 weeks at 2 years and 40 percent discontinuing treatment within 2 years.

Frequencies of activated T cell populations increase in breast milk of HCMV-seropositive mothers during local HCMV reactivation.

Human cytomegalovirus (HCMV) can reactivate in the mammary gland during lactation and is shed into breast milk of nearly every HCMV-IgG-seropositive mother of a preterm infant. Dynamics of breast milk leukocytes during lactation, as well as blood leukocytes and the comparison between both in the context of HCMV reactivation is not well understood. Here, we present the BlooMil study that aimed at comparing changes of immune cells in blood and breast milk from HCMV-seropositive- vs -seronegative mothers, collected at four time ranges up to two months post-partum. Viral load was monitored by qPCR and nested PCR. Multiparameter flow cytometry was used to identify leukocyte subsets. CD3+ T cell frequencies were found to increase rapidly in HCMV-seropositive mothers' milk, while they remained unchanged in matched blood samples, and in both blood and breast milk of HCMV-seronegatives. The activation marker HLA-DR was more strongly expressed on CD4+ and CD8+ T cells in all breast milk samples than matched blood samples, but HCMV-seropositive mothers displayed a significant increase of HLA-DR+ CD4+ and HLA-DR+ CD8+ T cells during lactation. The CD4+/CD8+ T cell ratio was lower in breast milk of HCMV-seropositive mothers than in the blood. HCMV-specific CD8+ T cell frequencies (recognizing pp65 or IE1) were elevated in breast milk relative to blood, which might be due to clonal expansion of these cells during local HCMV reactivation. Breast milk contained very low frequencies of naïve T cells with no significant differences depending on serostatus. Taken together, we conclude that the distribution of breast milk leukocyte populations is different from blood leukocytes and may contribute to the decrease of breast milk viral load in the late phase of HCMV reactivation in the mammary gland.

A Practical Way to Balance Single Phase Loads in a Three Phase System at Distribution and Unit Level

The crucial worry in the production of electricity is to be certain that the supplied electricity meets international standards. The growing environmental alerts and the advancement in technology led to the integration of eco-friendly energy sources such as photovoltaic cells and wind turbines to local power grids. Although they provide additional power, the hazardous distribution of these sources in the grid does not benefit power quality measures. This, in addition to the un-linearity in consumption curves, make load balancing at distribution level a must to apply. To achieve the sought balance, load reconfiguration is the solution to be applied. This paper focuses on a practical way that rearranges the loads over the three phases at the unit itself. These changes guarantee electric bills drop and environmental benefits that result from fuel consumption reduction. Practical balancing (PB) is a switching mechanism that guarantees the loads are balanced according to constraints. The main difference between PB and previously proposed techniques such as the Phase commitment (PC) algorithm, The Heuristic (HE) method and the Modified Leap Frog optimization technique is that PB is implementable on real device while others are not. Using the practical balancing algorithm, the percentage of unbalance dropped to 0.38% and 0.43% for the same 15 and 150 loads testing systems used for the phase commitment algorithm. In addition, the average unbalance dropped to 1.6 A and 1.26 A, respectively and the neutral current dropped to 2.08 A and 1.9 A, respectively. The study was conducted on real data for different types of loads.

Effectiveness and safety of brolucizumab in the treatment of neovascular age-related macular degeneration

This study analyzes the effectiveness and safety of brolucizumab in the treatment of neovascular age-related macular degeneration (nAMD) in real clinical practice. The study included patients with nAMD who received brolucizumab treatment and evaluated the changes in best-corrected visual acuity (BCVA), central retinal thickness (CRT), macular volume, as well as the number of injections and adverse events. The group of previously treated patients included 28 subjects (28 eyes) that were switched to brolucizumab with a loading phase. By 12 months, BCVA changed from 0.43±0.29 to 0.33±0.27 LogMAR (p=0.11), CRT decreased from 281.5±58.2 to 239.9±45.6 µm (p=0.02). The group of previously untreated patients included 29 subjects (29 eyes). By 12 months, BCVA changed from 0.47±0.32 to 0.40±0.30 LogMAR (p=0.09), CRT decreased from 333.2±77.3 to 226.2±49.6 µm (p<0.001). Patients received 6.3±0.7 injections. In this group, baseline choroidal thickness showed a statistically significant correlation with final visual acuity (r=0.54; p<0.05) and CRT (r= -0.5; p<0.05). The group of previously treated patients switched without a loading phase included 18 patients (18 eyes). By 6 months, BCVA changed from 0.42±0.2 to 0.37±0.26 LogMAR (p=0.42). CRT remained stable at 285.6±56.9 µm (p=0.97). No adverse events related to intraocular inflammation were reported during the course of 385 injections. Brolucizumab therapy helps achieve significant anatomical and functional improvements in real clinical practice both in patients switched from previous treatments and in treatment-naïve patients. Greater baseline choroidal thickness may be associated with better anatomical and functional outcomes with brolucizumab treatment.

Polymorphic phase transition in CoCrNi medium-entropy alloy under impact loadings

Polymorphic phase transition in metallic materials under high pressure is a critical aspect of dynamic properties and has been attracting a great interest. Despite the extensive researches have been made on understanding of this phase transition in traditional single-principal element alloys, little is known about the phase transition in recently emergent multi-principal medium and high entropy alloys, especially compressed under high strain rates. In this work, based on molecular dynamic simulations, three impact loading strategies with distinct loading paths, such as single-shock, double-shock and ramp-wave loading are carried out on the single crystalline CoCrNi medium-entropy alloy (MEA) to investigate the phase transition under high strain-rate compression. Careful characterizations show that the phase transition of CoCrNi MEA is loading-path dependent, as evidenced by the significant differences in macroscopic pressure evolution and microscopic structural phase transition among the samples under various thermodynamic paths. An intriguing pressure “overshoot” is found and demonstrated as the characteristic of the critical structural phase transition from face-centered cubic (FCC) structure to hexagonal-close-packed (HCP) structure mediated by body-centered cubic (BCC) like clusters. We show that such loading-path dependence is attributed to the strain rate and temperature rise in the loading process, which control the evolution of microstructure and deformation field. The inherent correlation between the atomistic process of phase transition and loading strategies results in polymorphic phase transition under high strain rates. These findings shed new light on the nature of impact phase transition of multi-principal alloys.

Tectonic and climatic significance of Oligocene-Miocene eolian sandstones in the Andean foreland basin of Argentina

Late Oligocene-early Miocene aridification in the retroarc foreland basin adjacent to the southern central Andes was recorded by widespread eolian conditions that coincided with accelerated subsidence driven by the main phase of Andean tectonic loading. An extensive eolian dune system, which is rare in most foreland basins, indicates specific conditions in terms of climate (aridity), atmospheric circulation, orography, sediment sources, dispersal patterns, and accommodation space. Detrital zircon U-Pb geochronological results for eolian sandstones spanning 20 foreland localities in northwestern to west-central Argentina, from 22°S to 36°S, reveal relatively localized Andean sources rather than regional cratonic provenance. Clastic detritus was largely derived from Phanerozoic igneous and sedimentary rocks of the Andean magmatic arc and retroarc fold-thrust belt during initial shortening-induced uplift of hinterland regions such as the Western Cordillera, Principal Cordillera, and Frontal Cordillera. This provenance record provides the earliest evidence for major westerly winds, transporting Andean detritus broadly eastward to the foreland basin (with common axial northward deflections) during a climate shift marked by the latest Oligocene-earliest Miocene inception of arid conditions. In addition to the climatic implications, independent stratigraphic data provide the basis for a compilation of sediment accumulation histories showing that eolian deposition was synchronous with accelerated subsidence attributable to enhanced Andean shortening. We propose that accelerated Andean uplift in the latest Oligocene-early Miocene generated rain-shadow conditions contemporaneous with increased sediment accommodation in the foreland basin, underscoring the important influence of tectonic processes on regional climate.

STUDY OF PHASE VOLTAGE AND LOAD SYMMETRATION IN ACTIVE-ADAPTIVE DISTRIBUTION ELECTRIC NETWORKS

Networks of 0.4 kV are characterized by a large unbalance of loads in phases. Current unbalance leads to voltage unbalance and additional losses of electrical energy. As a result, the voltage at the consumer may not meet the quality standards of electrical energy. In addition, due to unbalance, the service life of electrical equipment is reduced. Since the effect of stress balancing significantly depends on the place of balancing loads on the line, the paper proposes to determine the places of balancing loads by solving a multicriteria optimization problem. The paper proposes an objective function that minimizes active power losses and contains the total index of active power losses and indices of voltage unbalance coefficients in the negative and zero sequence.&#x0D; &#x0D; The purpose of the study is to obtain an effective objective function for determining the places of balancing loads and voltages in the network, which ensures a minimum of active power losses and the values of the voltage unbalance factors within the required limits; conduct a study of balancing loads and voltages depending on the places of balancing.&#x0D; &#x0D; Materials and methods. In the work, methods for calculating electrical networks were used, taking into account voltage losses and active power. To study the places of balancing loads and voltages, the method of multicriteria optimization with restrictions was used. The study of the objective function was carried out on a mathematical model of a low voltage overhead line. All calculations were carried out in MATLAB.&#x0D; &#x0D; Research results. A review and analysis of modern tools and methods for balancing loads and voltages in low voltage networks has been carried out. As a result of the analysis, it was concluded that there is no algorithm for determining the places of load balancing in low-voltage networks that provide minimal active power losses and the values of the voltage unbalance factors within the required limits. The task of finding places for balancing loads and voltages is a multiobjective optimization problem with constraints. Therefore, an objective function was proposed that minimizes active power losses in the network and contains the total index of active power losses and indices of voltage unbalance coefficients for the reverse and zero sequence. To study the proposed objective function, a model overhead line of a 0.4 kV network with specified phase loads and voltages was used. For the model line, the calculation of active power losses and the values of the voltage unbalance coefficients in the initial mode before balancing was carried out. All calculations were carried out for each phase separately. At the first stage, the calculation of the sensitivity coefficients of active power losses and the sensitivity coefficients for the voltage unbalance coefficients was carried out. To study the balancing of loads, nodes were selected that have the maximum values of the sensitivity coefficients. It follows from the calculation results that the best effect from balancing is observed when balancing loads simultaneously in two nodes: in the node with the highest value of the total sensitivity factor of active power losses, and in the node with the maximum value of the phase sensitivity factor of active power losses. When balancing loads in only one of the nodes, the most optimal of the selected ones will be the node most remote from the TS. We also obtained weight coefficients that provide a minimum of the objective function.&#x0D; &#x0D; Conclusions. The proposed objective function is effective for determining the places of load and voltage balancing in low voltage networks. In this case, the best effect is observed when balancing loads in nodes that have the highest values of the sensitivity coefficients of total active power losses and by phases. The node most remote from the TP will be more optimal. When balancing loads in places determined using the proposed objective function, it is possible to reduce power losses and ensure the values of the unbalance coefficients in the nodes on the line less than the maximum allowable value.

CALCULATION OF POWER TRANSFORMER INDUCTANCE MATRIX

Practical calculations of electric equipment and electric networks are performed using equivalent circuits. Without taking into account saturation phenomena, electromagnetic processes in a power transformer are described by a system of linear equations, which can be represented in matrix form. The transformer inductance matrix contains self and mutual winding inductances, whose values for one phase are determined directly from the passport data containing the results of no-load and short circuit experiments. Mutual inductances between phases depending on the type and size of the magnetic core are not usually given in the transformer documentation. It does not allow to simulate the operating modes that differ from the steady state with uniform phase load.&#x0D; &#x0D; The purpose of the work is to develop an algorithm for calculating elements of the power transformer inductance matrix according to its passport data and magnetic circuit parameters.&#x0D; &#x0D; The scientific novelty lies in use of information about magnetic circuit type and size to determine elements of the inductance matrix.&#x0D; &#x0D; Materials and methods. Methods of linear electric and magnetic circuit theory are used in the work.&#x0D; &#x0D; Results. The proposed algorithm for calculation of power transformer inductance matrix includes three stages: calculation of self and mutual inductances for one phase; construction of an equivalent circuit for a magnetic circuit and calculation of magnetic fluxes in order to take into account the mutual influence of windings on various phases; assembly of the inductance matrix of three-phase transformer. A method is proposed for constructing the transformer inductance matrix with an arbitrary type of magnetic circuit, phases and windings quantity. The method involves preliminary calculation of the coefficient matrix that characterizes the magnetic circuit and depends mainly on its type and, to a less, on the ratio of geometric dimensions in rods and yokes. The coefficient matrix can be calculated in advance and used to determine the inductance matrix of a wide range of transformers.&#x0D; &#x0D; Conclusions. 1. The passport data of the transformer do not allow to model transformer operation at unbalanced load validly. 2. An algorithm for determining the inductance matrix of transformers has been developed. 3. A method for compilation of a transformer inductance matrix with an arbitrary type of magnetic circuit, the number of phases and windings is introduced. The practical significance of the algorithm is determined by the simplicity of algorithmizing, as well as by the possibility of using it in computer simulation of electrical circuits with transformers, for example, using the modified nodal analysis method.

Prediction of rock loading stages using average infrared radiation temperature under shear and uniaxial loading

Accurately predicting geologically rock loading phases under varying water levels is crucial to prevent rock engineering operations from severe geological hazards. Acoustic emission (AE) traditionally determines these phases, but machinery in rock projects can disrupt AE sensors, leading to imprecise data and potential accidents. To address this, our study tested a novel approaches using AE, Average Infrared Radiation Temperature (AIRT), Critical Slow Down Theory (CSDT), and Convolutional Neural Networks (CNNs) to predict rock loading phases accurately under different water conditions. The research findings are: (1) AE analysis divides the stress–strain curve into four phases: crack closure, elastic deformation, and stable and unstable crack propagations. Each phase exhibits distinct characteristics in terms of AE signal behavior. (2) AIRT analysis reveals specific patterns during different loading phases. The AIRT and cumulative AIRT have distinct trends in different phases. (3) The AIRT sequence's fractal dimension shows distinct trends during loading phases: it initially rises during the elastic phase and then declines. Fractal dimensions for crack closure, elastic deformation, and stable crack propagation increase, while that for unstable crack propagation decreases with water content. 4) The stress–strain curve phases were successfully predicted by using AIRT and CSDT, demonstrating a strong correlation with actual stress levels. Notably, this marks the first-time prediction of phases through non-destructive tests (IR and CSDT), where CSDT fluctuations at each stage can serve as early indicators of rock failure.5) The proposed CNNR model achieves high accuracy (98%) in predicting different phases of the stress curve using AIRT. It particularly performs well in the elastic deformation and stable crack propagation phases, with only a few instances of false negative predictions. The model shows promising potential for effective and safe geological projects, especially under varying water conditions. The findings contribute to the understanding of rock behavior and offer insights for the design of safer and more efficient rock engineering projects.

The effect of an explosive shock wave on the plate of a protective structure of a critical infrastructure

The article presents the outcomes of an analysis on the stress-strain conditions of reinforced concrete structures subjected to an explosive shock wave resulting from the detonation of a combat unit from a kamikaze drone against a protective screen. When designing protective structures for critical infrastructure, employing computer simulation enables an assessment of the genuine impact of explosive loading on the structural elements' strength. The active phase of explosive loading is exceptionally brief, lasting only a fraction of a second. Under such circumstances, modeling is best performed using explicit methods of direct integration in time.&#x0D; The structure considered in this work is a reinforced concrete slab supported by a metal beam cage with I-beam cross-sections, topped with a sand backfill. The study was executed within the SIMULIA Abaqus software suite, incorporating models depicting nonlinear material behavior in a three-dimensional context. Discretely positioned reinforcement was considered for reinforced concrete structures, and the "Concrete Damage Plasticity" model was applied for concrete, accounting for damage accumulation. The devised computational scheme for the shelter represents a section of the protective structure's roof under conditions of cyclic symmetry.&#x0D; The article elucidates the core principles of incorporating explosive loading according to algorithm CONWEP.The results demonstrate that during the detonation of a kamikaze drone, an explosive wave created a crater in the sand backfill, exposing the slab. The study illustrates the development of damage in the reinforced concrete slab at various time intervals. Despite the identified damage to the slab, the protective structure overall withstood the explosive load. The intensity of the explosive shock wave diminishes significantly as it propagates away from the explosion site.

Mechanics of woven roving/ mat laminate failure in a quasi-static tensile test

Based on tensile tests of non-standard specimens with large dimensions, an attempt was made to explain the mechanics of failure of woven roving/mat laminates with different numbers of layers. The need to use non-standard specimens in tests resulted from the impossibility of interpreting the processes taking place in tensile specimens in specimens with standard dimensions, the results of which are published in the scientific literature. In the tensile tests, four loading phases were observed, in which in the last two the structure of matrix was failed by micro- and macro-cracks, and finally by delamination through the laminates. To describe the fracture mechanics of the discussed laminates, the principle of energy equivalence was used in the transformation of elastic strain energy into binding energy. Although the processes of laminate destruction occur in the matrix, depending on the number of layers, it was found that two different processes of destruction of the internal structure with three variants of elastic strain energy distribution lead to the final delamination of the laminates. The use of energy to describe the failure of laminates in the third phase of specimen loading leads to the definition of such concepts as the dominance of failure stresses and the dominance of failure strains in the process of cracking the laminate structure. Experimental studies indicate a gradient distribution of binding energy towards the center of unloaded specimens, assumed on the basis of a literature review.