Search Results (3,272)

The growing demand for power and the rising awareness of the need to reduce carbon footprints have led to wider acceptance of photovoltaic (PV)-integrated microgrids. PV-based microgrids have numerous significant advantages over other distributed energy resources; however, creating a dependable protection scheme for the DC microgrid is difficult due to the closely resembling current and voltage profiles of PV array faults and line faults in the DC network. The conventional methods fail to clearly discriminate between them. In this regard, a fault-resilient scheme exploiting the inherent characteristics of Fourier–Bessel Series Expansion and Empirical Wavelet Transform (FBSE-EWT) has been utilized in the present work. In order to enhance the efficacy of the bagging tree-based ensemble classifier, Artificial Gorilla Troop Optimization (AGTO) has been used to tune the hyperparameters. The hybrid protection approach is proposed for accurate fault detection, discrimination between scenarios (source-side fault and line-side fault), and classification of various fault types (pole–pole and pole–ground). The discriminatory attributes derived from voltage and current signals recorded at the DC bus using the hybrid FBSE-EWT have been utilized as an input feature set for the AGTO tuned bagging tree-based ensemble classifier to perform the intended tasks of fault detection and discrimination between source faults (PV array faults) and line faults (DC network). The proposed approach has been found to outperform the decision tree and SVM techniques, demonstrating reliability in terms of discriminating between the PV array faults and the DC line faults and resilience against fluctuations in PV irradiance levels. Full article

The complex topology of shipboard DC microgrids and the strong coupling between positive and negative poles during faults pose significant challenges for faulted-pole identification, especially under high-resistance conditions. To address these issues, this paper proposes a novel faulted-pole identification method based on S-Transformation and convolutional neural networks (CNNs). Single-ended voltage and current measurements from the generator side are used to generate time–frequency spectrograms via S-Transformation, which are then processed by a CNN trained to classify the faulted pole. This approach avoids reliance on complex threshold settings. Simulation results on a representative shipboard DC microgrid demonstrate that the proposed method achieves high accuracy, fast response, and strong robustness, even under high-resistance fault scenarios. The method significantly enhances the selectivity and reliability of fault protection, offering a promising solution for advanced marine DC power systems. Compared to conventional fault-diagnosis techniques, the proposed model achieves notable improvements in classification accuracy and computational efficiency for line-fault detection. Full article

To enhance the electromagnetic performance of flat-wire permanent magnet synchronous motors, three different groove structures were designed for the rotor, and a multi-objective optimization algorithm combining a genetic algorithm (GA) with the TOPSIS method was proposed. Firstly, an 8-pole 48-slot flat-wire motor model was established, and the cogging torque was analytically calculated to compare the motor’s performance under different groove schemes. Secondly, global multi-objective optimization of the rotor groove dimensions was performed using a combined simulation approach involving Maxwell, Workbench, and Optislang, and the optimal rotor groove size structure was selected using the TOPSIS method. Finally, a comparative analysis of the motor’s performance under both rated-load and no-load conditions was conducted for the pre- and post-optimization designs, followed by verification of the mechanical strength of the optimized rotor structure. The research results demonstrate that the combined optimization approach utilizing the genetic algorithm and the TOPSIS method significantly enhances the torque characteristics of the motor. The computational results indicate that the average torque is increased to 165.32 N·m, with the torque ripple reduced from 28.37% to 13.32% and the cogging torque decreased from 896.88 mN·m to 187.9 mN·m. Moreover, the total distortion rates of the air-gap magnetic flux density and the no-load back EMF are significantly suppressed, confirming the rationality of the proposed motor design. Full article

The aim of the article is to determine the control range of a multiphase squirrel cage induction generator with more than three stator phases, operating in a wide range of driving speeds. The generator produces an output DC voltage using a multiphase converter operating as a PWM rectifier. The entire speed range is divided into intervals in which the sequence of stator phase voltages and, in effect, the number of pole pairs, is changed. In each interval, the output voltage is regulated by the frequency and amplitude of the stator voltages causing the highest possible power efficiency of the generator. The system can be scalar controlled or regulated using field orientation. Generator characteristics are calculated based on the set of steady-state equations derived from differential equations describing the multiphase induction machine. The calculation results are compared with simulations and with the steady-state measurement of the vector-controlled nine-phase generator. Recognizing the reliability of the obtained results, calculations are performed for a twelve-phase generator, obtaining satisfactory efficiency from 70% to 85% in the generator speed range from 0.2 to 1.0 of the assumed reference speed of 314 rad/s. The generator producing DC voltage can charge an electrical energy storage system or can be used directly to provide electrical power. This solution is not patented. Full article

Membranous nephropathy (MN) is the most prevalent cause of nephrotic syndrome (NS) in adults, and it can be primary (idiopathic) with an unknown cause or secondary due to a variety of conditions (lupus, infections, malignancies, medications, etc.). It progresses to chronic kidney disease (CKD) in up to 60% of patients, and 10 to 30% develop end-stage kidney disease (ESKD). This retrospective study examines the importance of specific factors, including baseline demographic and clinical data, kidney biopsy PH findings, and selected biochemical parameters, influencing MN outcomes after 10 years of follow-up. The cohort included 94 individuals in whom a diagnosis of MN was established by percutaneous biopsy of the left kidney’s lower pole at the University Clinical Center of Serbia (UCCS) between 2008 and 2013. According to the outcomes, patients were divided into three groups: the recovery (Rec) group, with complete remission, including normal serum creatinine (Scr) and proteinuria (Prt), the group with development of chronic kidney disease (CKD), and the group with development of end-stage kidney disease (ESKD). Nephropathologists graded pathohistological (PH) results from I to III based on the observed PH findings. During the follow-up period, 33 patients were in the Rec group, CKD developed in 53 patients, and ESKD developed in 8 patients. Baseline creatinine clearance levels (Ccr), Scr, and uric acid (urate) were found to be significantly associated with the outcomes (p < 0.001). The lowest values of baseline Scr and urate were observed in the Rec group. The presence of acute kidney injury (AKI) or CKD at the time of kidney biopsy was associated with the more frequent development of ESKD (p = 0.02). Lower Ccr was associated with a higher likelihood of progressing to CKD (B = −0.021, p = 0.014), whereas older age independently predicted progression to ESKD (B = 0.02, p = 0.032). Based on this study, it was concluded that the most important biochemical and clinical factors that are associated with the outcomes of this disease are the values of Scr, Ccr, and urate and the existence of CKD at the time of kidney biopsy. Unlike most previous studies, the presence of HTN had no statistical significance in the outcome of the disease. Full article

To enhance the anti-overturning performance of poles and prevent tilting or collapse, a prefabricated foundation for distribution lines is developed. Field tests are conducted on five groups of foundations. Based on the test results, finite element analysis (FEA) is employed to investigate the influence of different factors—such as pole embedment depth, foundation locations, soil type, and soil parameters—on the anti-overturning performance of pole prefabricated foundations. The results indicate that under ultimate load conditions, the reaction force distribution at the base of the foundation approximates a triangular pattern, and the lateral earth pressure on the pole follows an approximately quadratic parabolic distribution along the depth. When the foundation size increases from 0.8 m to 0.9 m, the bearing capacity of the prefabricated foundation improves by 8%. Furthermore, when the load direction changes from 0° to 45°, the foundation’s bearing capacity increases by 14%. When the foundation is buried at a depth of 1.0 m, compared with the ground position, the ultimate overturning moment of the prefabricated foundation increases by 10%. Based on field test results, finite element simulation results, and limit equilibrium theory, a calculation method for the anti-overturning bearing capacity of prefabricated pole foundations is developed, which can provide a practical reference for the engineering design of distribution line poles and their prefabricated foundations. Full article

The problem of protecting 7075 Al alloy trekking poles from corrosion in complex outdoor environments was addressed using a composite conversion coating system. This system comprised Na₂MoO₄, NaF, CoSO₄·7H₂O, ethylenediaminetetraacetic acid-2Na, and H₂(TiF₆). The influences of this system on the properties of the coating layer were systematically studied by adjusting the pH of the coating solution. The conversion temperature and pH were the pivotal parameters influencing the formation of the conversion coating. The pH substantially influenced the compactness of the coating layer, acting as a regulatory agent of the coating kinetics. When the conversion temperature and pH were set to 40 °C and 3.8, respectively, the prepared coating layer displayed optimal performance in terms of compactness and protective properties. Therefore, this parameter combination favours the synthesis of high-performance conversion coatings. Microscopy confirmed the formation of a continuous, dense composite oxide film structure under these conditions, effectively blocking erosion in corrosive media. Furthermore, the optimised process led to substantial enhancements in the environmental adaptabilities and service lives of the components of trekking poles, thus establishing a theoretical foundation and technical reference for use in the surface protection of outdoor equipment. Full article

A multi-objective genetic algorithm is tailored to optimize the design of a wavelength interleaver/deinterleaver device. An interleaver combines data streams from two physical channels into one. The deinterleaver does the opposite job. The WDM requirements for this device include channel spacing of 50 GHz, channel bandwidth of 20 GHz, free spectral range of 100 GHz, maximum channel dispersion of 30 ps/nm, and maximum crosstalk of −23 dB. The challenges for the optimization process include the lack of a closed-form expression for the device performance and the trade-off between the conflicting performance parameters. So, for this multi-objective problem, the proposed approach maneuvers to find a compromise between the performance parameters within a few minutes, saving the designer the laborious design process previously proposed in the literature, which relies on visually inspecting the Z-plane for the dynamics of the transmission poles and zeros. Designs of better performance are achieved, with fewer ring resonators, a channel dispersion as low as 1.6 ps/nm, and crosstalk as low as −30 dB. Full article

In this study, a current vector pattern is analyzed for inter-turn fault (ITF) diagnosis of induction machines (IMs), and an ITF diagnosis algorithm is proposed. When an ITF occurs in IMs, a negative-sequence current is generated due to fault resistance, even though a positive-sequence voltage is applied to IMs. Based on the mathematical model of IMs with an ITF, the current vector patterns in the stationary coordinate frame are analyzed. The superposition of positive- and negative-sequence components results in an elliptical current vector trajectory, and its orientation varies depending on the fault conditions. The co-simulation using finite element analysis and circuit simulation is implemented to analyze the current vector pattern of IMs with an ITF. The ITF diagnosis is proposed based on the current vector pattern. A 12 kW, four-pole, three-phase IM and terminal box, which was used to implement an ITF, is manufactured, and an experiment setup is established to verify the ITF algorithm. The effectiveness of the proposed ITF algorithm is validated through experimental verification of the manufactured IM and terminal box. Full article

Replication timing (RT), the temporal order of DNA replication during S phase, influences regional mutation rates, yet the mechanistic basis for RT-associated mutagenesis remains incompletely defined. To identify drivers of RT-dependent mutation biases, we analyzed whole-genome sequencing data from cells with disruptions in DNA replication/repair genes or exposed to mutagenic compounds. Mutation distributions between early- and late-replicating regions were compared using bootstrapping and statistical modeling. We identified 14 genes that exhibit differential effects in early- or late-replicating regions, encompassing multiple DNA repair pathways, including mismatch repair (MLH1, MSH2, MSH6, PMS1, and PMS2), trans-lesion DNA synthesis (REV1) and double-strand break repair (DCLRE1A and PRKDC), DNA polymerases (POLB, POLE3, and POLE4), and other genes central to genomic instability (PARP1 and TP53). Similar analyses of mutagenic compounds revealed 19 compounds with differential effects on replication timing. These results establish replication timing as a critical modulator of mutagenesis, with distinct DNA repair pathways and exogenous agents exhibiting replication timing-specific effects on genomic instability. Our systematic bioinformatics approach identifies new DNA repair genes and mutagens that exhibit differential activity during the S phase. These findings pave the way for further investigation of factors that contribute to genome instability during cancer transformation. Full article

Endometrial cancer (EC) is the most common gynecological malignancy in developed countries. Risk factors for EC include metabolic alterations (obesity, metabolic syndrome, insulin resistance), hormonal imbalance, age at menopause, reproductive factors, and inherited conditions, such as Lynch syndrome. For the inherited forms, several genes had been implicated in EC occurrence and development, such as POLE, MLH1, TP53, PTEN, PIK3CA, PIK3R1, CTNNB1, ARID1A, PPP2R1A, and FBXW7, all mutated at high frequency in EC patients. However, gene function impairment is not necessarily caused by mutations in the coding sequence of these and other genes. Gene function alteration may also occur through post-transcriptional control of messenger RNA translation, frequently caused by microRNA action, but transcriptional impairment also has a profound impact. Here, we review how chromatin modifications change the expression of genes whose impaired function is directly related to EC etiopathogenesis. Chromatin modification plays a central role in EC. The modification of chromatin structure alters the accessibility of genes to transcription factors and other regulatory proteins, thus altering the intracellular protein amount. Thus, DNA structural alterations may impair gene function as profoundly as mutations in the coding sequences. Hence, its central importance is in the diagnostic and prognostic evaluation of EC patients, with the caveat that chromatin alteration is often difficult to identify and needs investigations that are specific and not broadly used in common clinical practice. The different phases of the healthy endometrium menstrual cycle are characterized by differential gene expression, which, in turn, is also regulated through epigenetic mechanisms involving DNA methylation, histone post-translational modifications, and non-coding RNA action. From a medicolegal and policy-making perspective, the implications of using epigenetics in cancer care are briefly explored as well. Epigenetics in endometrial cancer is not only a topic of biomedical interest but also a crossroads between science, ethics, law, and public health, requiring integrated approaches and careful regulation. Full article

A novel prefabricated pile foundation is presented to improve the disaster resistance of the pole line. Bearing performance analysis of prefabricated inclined pile foundations for electric poles under downward pressure-horizontal loading is carried out, and the effects of prefabricated foundation dimensions and pile inclination on the horizontal load–displacement curves at the top of the poles, the horizontal displacement and settlement at the top of the piles, the horizontal displacement and tilt rate of the poles’ bodies and piles bending moments are investigated. The findings indicate the following: as the prefabricated foundation size grows, the bearing capacity of the foundation improves, and the anti-overturning ability of the electric pole improves; the foundation size increases from 0.9 m to 1.35 m, the anti-overturning bearing capacity of the foundation increases by 15.77%, the maximum bending moment of the foundation pile body increases by 19.7%, and the maximum bending moment occurs at about 0.2 m of the pile body; the bearing capacity of inclined piles is larger than that of straight piles—with an increase in the pile inclination angle, the foundation bearing performance increases, and the overturning bearing capacity of the poles increases; the pile inclination angle grows from 0° to 20°, the overturning bearing performance of the foundation increases by 19.2%, the maximum bending moment of the foundation piles reduces by 21.2%, and the maximum of the bending moment occurs at the pile body at a position of about 0.2 m. Full article

Rationale: The ProMisE molecular classification improves risk assessment in endometrial cancer (EC), but 3–11% of cases exhibit overlapping molecular features, complicating clinical decisions. We analyzed the prevalence and clinicopathological profiles of multiple-classifier ECs in a large Polish cohort. Methods: In this retrospective study (2022–2025), 1075 ECs from four institutions were classified by MMR and p53 immunohistochemistry and POLE exon sequencing. Tumors showing ≥2 molecular features (e.g., MMRd–p53abn, POLEmut–p53abn) were categorized as multiple-classifier ECs. Results: Multiple-classifier ECs comprised 6.9% (74/1075), with MMRd–p53abn (3.9%) being most common. These tumors exhibited more aggressive features vs. MMRd-only: G3 (28.57% vs. 11.79%, p = 0.002), non-endometrioid histology (11.9% vs. 2.85%, p = 0.018), and high–intermediate/high-risk (HIR/HR) groups (59.52% vs. 37.80%, p = 0.001). POLEmut–p53abn (N = 4) and POLEmut–MMRd–p53abn (N = 10) tumors showed advanced stages (75% and 40% FIGO III–IV, respectively), in contrast to classical POLEmut tumors (6.7% FIGO III–IV), and higher rates of nodal metastases. Conclusions: Co-occurrence of molecular classifiers, including triple-classifier tumors, correlates with more adverse profiles and may undermine current stratification paradigms. This study emphasizes the need to further investigate and refine molecular risk models to account for overlapping profiles. Full article

Alpine scree, a distinctive plateau ecosystem, serves as habitat for numerous rare and endangered species. However, current research does not differentiate it from desert in terms of spatial boundary, hindering biodiversity conservation and ecological monitoring efforts. Using the Tibetan Plateau as a case study, we defined the spatial boundary of alpine scree based on its surface formation process and examined its distribution and long-term evolution. The results show that in 2020, alpine scree on the Tibetan Plateau covered 73,735.34 km², 1.5 times the area of glaciers. Alpine scree is mostly distributed at elevations between 4000 and 6000 m, with a slope of approximately 30–40 degrees. Characterized by low temperature and sparse rainfall, the regions are located in the humid zone. From 1975 to 2020, the area of alpine scree initially increased before declining, with an overall decrease of 560.68 km². Climate warming was the primary driver of these changes, leading to an increase in scree from 1975 to 1995 and a decrease in scree from 1995 to 2020. Additionally, between 1975 and 2020, the Tibetan Plateau’s grasslands shifted upward by 16.47 km². This study enhances our understanding of the spatial distribution and dynamics of this unique ecosystem, alpine scree, offering new insights into climate change impacts on alpine ecosystems. Full article

In this paper, a bearing- and transformer-integrated electric excitation synchronous motor excitation system (bearing-integrated rotary transformer) is proposed to support the motor rotor and energy transmission of excitation systems. Firstly, the working principle of the bearing-integrated rotary transformer is discussed. Secondly, the structure and electromagnetism of the bearing-integrated rotary transformer are designed through the processes and principles of pole slot matching, stator/rotor size, winding, and the magnetic regulating needle. Thirdly, the bearing-integrated rotary transformer undergoes an electromagnetic–thermal simulation. Finally, a prototype of the bearing-integrated rotary transformer is manufactured, and the electromagnetic and transmission characteristics are tested, verifying the correctness of the proposed scheme and providing additional ideas for the improvement of synchronous motor excitation systems. Full article