Common Mode Research Articles

Influence of bolt preload of anchors on bond-slip behavior of fiber fabric-steel interface

Bond-slip behavior is a common failure mode in steel structures reinforced with fiber fabric. Premature debonding of the fiber fabric significantly impacts the effectiveness of steel structure reinforcement. In this study, a gripping anchor is proposed to enhance the reliability of the interface between fiber fabric and steel plates. Experimental investigations were conducted to analyze the influence of anchor bolt preload on the double shear joint between fiber fabric and steel plates. 41 specimens were prepared and tested to explore the effects of parameters such as bolt preload, anchor position, number and type of fiber fabric layers, and bond length on load-bearing capacity. Comparative analyses were conducted on failure modes, ultimate loads, and stress-strain distributions of the specimens. Experimental results indicate that the position of the anchor has a minimal impact on the ultimate bearing capacity of the specimen. However, anchors positioned closer to the joint end exhibit lower ductility upon failure. A novel predictive model was developed to characterize the bond-slip behavior of preload applied to carbon fiber fabric and steel plates. The theoretical model of the ultimate bearing capacity in the yield stage fits well with the experimental results of specimens with three layers of carbon fiber fabric, with a difference range of 0.34 % to 14.97 % compared to actual results. This indicates that the model has high accuracy in predicting stress-strain and bearing capacity.

A local positive feedback loop-reused technique for enhancing performance of folded cascode amplifier

A current-reused folded cascode operational transconductance amplifier (OTA) using a local positive feedback (LPFB) technique has been proposed in previous literature, which does not achieve maximum unity gain-bandwidth (GBW). Besides, the stability of LPFB in the LPFB-OTA is limited by local common mode feedback (LCMFB) resistors. Based on the analysis, a local positive feedback loop-reused (LPFBR) technique is proposed to improve the performance of conventional LPFB OTA. For a fair comparison, both conventional and proposed OTAs working at saturation region are designed and simulated in SMIC 0.18μm process. The simulated results demonstrate that the proposed LPFBR-OTA has almost 10.5 times the bandwidth and maintains stability compared to that of the conventional LPFB-OTA under the condition that LCMFB resistors are increased by a factor of 10.

Comparative Analysis of Space Vector Pulse-Width Modulation Techniques of Three-Phase Inverter to Minimize Common Mode Voltage and/or Switching Losses

Comparative Analysis of Space Vector Pulse-Width Modulation Techniques of Three-Phase Inverter to Minimize Common Mode Voltage and/or Switching Losses

Evaluation and analysis of abrasive wear resistance of hybrid roller bearings under lubricant contamination

Abrasive wear is a common failure mode of rolling bearings. To enhance the resistance of traditional all-steel bearings to abrasive wear, the structure of traditional all-steel cylindrical thrust roller bearings has been appropriately adjusted, and hybrid roller bearings have been formed by replacing some of the steel rollers in the traditional bearings with ceramic rollers. The frictional performance of hybrid roller bearings under lubricant contamination conditions was analyzed, and the wear reduction mechanism was discussed. The results show that under the condition of lubricant contamination, replacing the appropriate amount of ceramic rollers not only helps reduce friction and decrease wear but also contributes to improving the overall temperature rise of the bearing. Furthermore, when the total amount of contaminants is constant, a specific threshold exists for the impact of replacing the number of rolling elements on reducing mass loss. For a substantial reduction in wear with hybrid roller bearings, the replacement rollers should constitute at least one-fifth of the total number of rollers. The wear reduction observed in hybrid roller bearings results from a combination of crushing and refinement, grinding and finishing, and self-healing mechanisms.

The Limits of the Metapopulation: Lineage Fragmentation in a Widespread Terrestrial Salamander (Plethodon cinereus)

Abstract In vicariant species formation, divergence results primarily from periods of allopatry and restricted gene flow. Widespread species harboring differentiated, geographically distinct sublineages offer a window into what may be a common mode of species formation, whereby a species originates, spreads across the landscape, then fragments into multiple units. However, incipient lineages usually lack reproductive barriers that prevent their fusion upon secondary contact, blurring the boundaries between a single, large metapopulation-level lineage and multiple independent species. Here, we explore this model of species formation in the Eastern Red-backed Salamander (Plethodon cinereus), a widespread terrestrial vertebrate with at least 6 divergent mitochondrial clades throughout its range. Using anchored hybrid enrichment data, we applied phylogenomic and population genomic approaches to investigate patterns of divergence, gene flow, and secondary contact. Genomic data broadly match most mitochondrial groups but reveal mitochondrial introgression and extensive admixture at several contact zones. While species delimitation analyses in Bayesian Phylogenetics and Phylogeography supported 5 lineages of P. cinereus, genealogical divergence indices (gdi) were highly sensitive to the inclusion of admixed samples and the geographic representation of candidate species, with increasing support for multiple species when removing admixed samples or limiting sampling to a single locality per group. An analysis of morphometric data revealed differences in body size and limb proportions among groups, with a reduction of forelimb length among warmer and drier localities consistent with increased fossoriality. We conclude that P. cinereus is a single species, but one with highly structured component lineages of various degrees of independence.

Prostate cancer subtyping and differential methylation analysis based on the ETS family of transcription factors fusion genes

Prostate cancer (PCa) is a highly heterogeneous disease, encompassing various molecular and clinical pathological subtypes. Fusion genes play a facilitating role in the occurrence and progression of PCa. We categorized PCa samples into the ETS family of transcription factors fusion positive and fusion negative subtypes based on fusion genes. This subtyping method is closely related to the epigenomic DNA methylation profiles of PCa, with each sample cluster including more than 85% of the patients. We conducted an analysis of the distribution of the ETS family fusion genes on chromosomes, fusion modes within reading frames, and predictions of structural domains. Among these, the highest frequency of the ETS family related fusion genes occurred on chromosome 21. Compared to the parental genes, fusion genes exhibited new structural domains, such as IG_like, and the most common fusion mode was out-of-frame fusion. The correlation between the methylation levels of hypermethylated CpG sites and the expression levels of their corresponding mRNAs indicates that CD8A and B3GNT5 (with correlations of − 0.388 and − 0.253, respectively) could serve as potential prognostic markers for PCa.

Coordinated referral and scheduling decisions for specialized healthcare services

This paper studies the coordination of referral and scheduling policies where access to specialized medical services, such as surgical procedures, imaging or other consultations, is managed through a centralized intake system. In this increasingly common mode of operation, a central body makes decisions regarding the allocation of patients between a set of providers, followed by the provider taking control of the scheduling and delivery of the required service. To study the coordination of the allocation and scheduling policies we present a sequential optimization model where both referrer and provider attempt to maximize the proportion of a heterogeneous set of patients receiving treatment within a targeted wait time. Motivated by observations of performance thresholds in queueing systems, we introduce an achievable region model which permits study of providers who vary in ability to coordinate scheduling different patient streams. We characterize optimal referral and scheduling policies for a range of demand patterns and operational abilities. We find that the optimal referral policy can result in large discrepancies in outcomes for different patient types but that the discrepancy in outcomes is muted when operational abilities are higher. In situations where operational abilities are low, it is optimal for the providers to prioritize patients by stream. Low capacity for both providers results in an optimal referral and scheduling policy where certain patients streams are deprioritized and with certainty will not be seen within their wait time targets. We also study the cost of enforcing parity between patient classes and find that the cost is reduced when providers have higher operational abilities. This paper illustrates how operational constraints lead to incentives to prioritize different patient streams. In particular, we show that when operations are challenging, a more hands-on design is required to ensure clinical intake systems maintain equitable access to the service.

A survey of nutritional education within the Holiday Activities and Food programme across England.

Nutritional education is a mandatory component of the Holiday Activities and Food (HAF) programme in England, yet there is a paucity of literature exploring how this component is delivered. The aim of this study was therefore to explore the delivery, content, dose and perceived impacts of nutritional education, at the HAF club level, across England. A self-completion, cross-sectional online survey design was adopted. Non-probability purposive sampling was used to collect data from HAF club leads (n = 147) from across England. Data were analysed using descriptive statistics and frequencies. Face-to-face nutritional education was the most common mode of delivery, with sessions mostly comprising of discussing food and nutrition. However, whilst the majority of clubs delivered the required number of nutritional education sessions per week, according to the Department for Education's guidelines, the time spent delivering individual nutritional education activities may not be sufficient to drive change in related skills and behaviours. Moreover, many clubs did not adopt a whole-family approach, and some did not deliver any nutritional education activities at all, which club leads attributed to a lack of material resources and ambiguity in the national HAF guidance. Nutritional education is delivered in a variety of ways across HAF clubs, based upon available local assets, resources and venues. Policy and practice recommendations include increased HAF funding to support clubs that lack material resources, national training in nutritional education, and evidence-informed guidance and practice.

Transverse magnetic field effects on diamond quantum sensor for EV battery monitor

Key implementation points for achieving full accuracy in simultaneous temperature and magnetic field measurement and linearity when applying diamond quantum sensors to electric vehicle (EV) battery monitors were investigated. Both the static and busbar current magnetic field are required to be aligned to the NV-axis. If misalignment should exist, the resonance frequency midpoint move in the direction opposite to the temperature change under a large busbar current due to the transverse magnetic field effect. Misalignment could be quantified with an accuracy of ±1° by analysing the resonance frequency midpoint change under a current of ±1,000 A. The transverse magnetic field effects compensation estimated from misalignment, confirmed that the resonance frequency midpoint changed consistently with temperature changes. Furthermore, linearity over a wide dynamic range also improved. Moreover, it will contribute to accurate alignment of the two sensors for differential detection to eliminate external noise as common mode. These are expected to expand the application of diamond sensors for high-precision measurement in a wide dynamic range.

Analysis of the Spatial Distribution and Common Mode Error Correlation in a Small-Scale GNSS Network.

When analyzing GPS time series, common mode errors (CME) often obscure the actual crustal movement signals, leading to deviations in the velocity estimates of station coordinates. Therefore, mitigating the impact of CME on station positioning accuracy is crucial to ensuring the precision and reliability of GNSS time series. The current approach to separating CME mainly uses signal filtering methods to decompose the residuals of the observation network into multiple signals, from which the signals corresponding to CME are identified and separated. However, this method overlooks the spatial correlation of the stations. In this paper, we improved the Independent Component Analysis (ICA) method by introducing correlation coefficients as weighting factors, allowing for more accurate emphasis or attenuation of the contributions of the GNSS network's spatial distribution during the ICA process. The results show that the improved Weighted Independent Component Analysis (WICA) method can reduce the root mean square (RMS) of the coordinate time series by an average of 27.96%, 15.23%, and 28.33% in the E, N, and U components, respectively. Compared to the ICA method, considering the spatial distribution correlation of stations, the improved WICA method shows enhancements of 12.53%, 3.70%, and 8.97% in the E, N, and U directions, respectively. This demonstrates the effectiveness of the WICA method in separating CMEs and provides a new algorithmic approach for CME separation methods.

Glenoid component cyclical failure decreases with increasing baseplate contact: a biomechanical study

BackgroundGlenoid baseplate loosening remains a common mode of failure in reverse shoulder arthroplasty. One of the key factors to baseplate stability is theorized to be maximization of baseplate backside contact. The purpose of this biomechanical study is to investigate the role of varying degrees of backside bony glenoid support in component stability for reverse total shoulder arthroplasty. MethodsTwenty synthetic scapular models were divided into 3 test groups of 5 scapulae with glenoid baseplate contacts of 40%, 60%, and 75%, and one control group with glenoid baseplate contact of 100%. Standardized application of a commercially available glenoid baseplate and glenosphere was performed. The scapulae were mounted on a linear bearing with a humeral component and polyethylene liner which were affixed to a biaxial servohydraulic fatigue testing system. Each specimen was loaded for 10,000 cycles or to failure, about a 55° arc along the glenosphere at a rate of 1 Hz as a 750 N compression load was applied. Failure was defined as fracture of the scapula with implant fixation compromise. Before and after loading, stability of the baseplate was assessed by quantifying the total motion between the model and the baseplate with digital calipers as a ramp load between 0 and 150 N was applied. Two-sample unpaired t-tests were performed with significance set at P < .05. ResultsBaseplate contacts of 40% (1623 ± 227, P = .0001), 60% (3299 ± 1170, P = .0001), and 75% (5615 ± 1587, P = .0077) demonstrated statistically significant decrease in the average number of cycles to failure in all cohorts compared to our control (8641 ± 1070). Cycles taken for initial cracks to progress to failure showed no significant differences; 40% contact (862 ± 452, P = .4751), 60% contact (1651 ± 996, P = .4318), 75% contact (2882 ± 1347, P = .0620), and 100% control (1166 ± 657). Baseplate contacts of 40% (6150.4 ± 444.0, P = .0006), 60% (4647.1 ± 552.3, P = .0072), and 75% (2927.8 ± 918.5, P = .2573) demonstrated increasing micromotion (pre-post cyclical loading) in all cohorts compared to our control (2074.7 ± 1164.6) with statistical significance at 40% and 60%. ConclusionThese biomechanical tests demonstrate that decreasing glenoid baseplate backside contact leads to increased micromotion and fewer cycles to failure. This supports the surgical goal of achieving maximal glenoid baseplate backside contact, suggesting that decreased glenoid baseplate support could contribute to significant loosening.

Novel Cascaded PV System with Common Mode Leakage Current Suppression

Novel Cascaded PV System with Common Mode Leakage Current Suppression

Generalized Modulation of Common Mode Voltage Reduction for Current Source Inverter in Balanced and Unbalanced Load Cases

Generalized Modulation of Common Mode Voltage Reduction for Current Source Inverter in Balanced and Unbalanced Load Cases

Common mode voltage mitigation in a three phase 21-level asymmetrical inverter fed induction motor

Common mode voltage mitigation in a three phase 21-level asymmetrical inverter fed induction motor

PWM Strategy for the Cancellation of the Common Mode Noise Generated in a Multicell DC–AC Converter

PWM Strategy for the Cancellation of the Common Mode Noise Generated in a Multicell DC–AC Converter

A magnetic diagnostic suite for the Pegasus-III experiment.

Pegasus-III is an ultralow aspect ratio spherical tokamak providing a dedicated US experiment for comparative solenoid-free startup studies. A new magnetic diagnostic suite for equilibrium and low frequency (<200kHz) magnetohydrodynamic mode analysis has been installed. These new diagnostics address the significant challenges of measuring magnetic field in a high noise environment with the majority constrained to fit in an 8mm diagnostic gap on the high field side. Electrostatic switching noise generated by the 16 independent current feedback-controlled power supplies produces dVcm/dt ∼ 1kV/μs and volt level common mode noise on the magnetics. Immunity to this switching noise is accomplished through differential signal runs and signal processing, along with end-to-end electromagnetic interference shielding. The magnetic measurements are simultaneously digitized at 1MHz and conditioned by precision 8 pole Butterworth filters with a corner frequency of 200kHz to prevent aliasing down to the 16-bit level over the full passband. Ex-vessel calibrations of the Bp coils were completed with a typical uncertainty of <0.5%. Stray toroidal field pickup from coil misalignment or positioning errors is corrected using a physics-based model. Comparisons of the corrected measurements to modeling agree to within 1.3% on average. This is within the 1.5% measurement uncertainty that a sensitivity analysis determined is needed for accurate fast boundary and equilibrium reconstruction.

Global subduction slow slip events and associated earthquakes.

Three decades of geodetic monitoring have established slow slip events (SSEs) as a common mode of fault slip, sometimes linked with earthquake swarms and in a few cases escalating to major seismic events. However, the connection between SSEs and earthquake hazard has been difficult to quantify and contextualize beyond regional studies. We aggregate a geodetic record of SSEs from subduction zones in the circum-Pacific region. In aggregate, earthquake rates increase up to threefold concurrent with and proximal to SSEs. The relative amplitude of this increase is correlated with the SSE size and, to a lesser extent, their depth and region. The subdued and coincident earthquake response to SSE stress transfer suggests a more limited role of static stress transfer and a very short relaxation timescale for the triggered seismicity. The observed range of behavior does not support a major connection between SSEs and earthquake hazard.

A Five-Level Common-Ground Inverter with Dynamic Voltage Boost and Fewer Elements for Photovoltaic Applications

Transformer-less multilevel inverters (TL-MLIs) are the subject of recent research due to their high-voltage or high-power capacity to convert low-voltage output from renewable energy sources into the desired output. They are also less expensive and smaller than traditional varieties. Nevertheless, leakage current is a common problem with these inverters. The proposed inverter aims to address this issue to the maximum extent possible. In the proposed inverter structure, there is a common ground for the input and output terminals. As a result, the overall common mode voltage (CMV) remains constant. This common ground feature short-circuits the Photovoltaic (PV) source to the grid parasitic capacitor, resulting in negligible leakage current. Furthermore, the proposed inverter boosts output voltage using the least amount of power devices and a single voltage source. The proposed inverter can be used modularly, increasing the number of output levels that can be achieved. The simulation results from MATLAB/Simulink and the conclusion of the mathematical analysis for the proposed inverter are shown. The results also demonstrate the output voltage boost capability, zero leakage current, and an appropriate total harmonic distortion for the output voltage and current waveforms.

Analytical Modeling and Experimental Validation of Common Mode Impedance in a Low- Voltage DC Micro-Grid

Analytical Modeling and Experimental Validation of Common Mode Impedance in a Low- Voltage DC Micro-Grid

Finite control set model predictive current control for three phase grid connected inverter with common mode voltage suppression

This research introduces an advanced finite control set model predictive current control (FCS-MPCC) specifically tailored for three-phase grid-connected inverters, with a primary focus on the suppression of common mode voltage (CMV). CMV is known for causing a range of issues, including leakage currents, electromagnetic interference (EMI), and accelerated system degradation. The proposed control strategy employs a system model that predicts the inverter’s future states, enabling the selection of optimal switching states from a finite set to achieve dual objectives: precise current control and effective CMV reduction, a meticulously designed cost function evaluates the potential switching states, balancing the accuracy of current tracking against the necessity to minimize CMV. The approach is grounded in a comprehensive mathematical model that captures the dynamics of CMV within the system, and it utilizes an optimization process that functions in real-time to determine the most suitable control action at each interval, Experimental validations of the proposed FCS-MPCC scheme have demonstrated its effectiveness in significantly improving the performance and durability of three-phase grid-connected inverters, Experimental validations of the proposed (MPC with CMV) scheme have demonstrated its effectiveness in significantly improving the performance and durability of three-phase grid-connected inverters. The proposed method achieved substantial reductions in CMV, notable improvements in current tracking accuracy, and extended system lifespan compared to conventional control methods.