Excess Charge Research Articles

MULTIBIT UPSETS OF ONBOARD SPACECRAFT ELECTRONICS FROM A SINGLE COSMIC RADIATION PARTICLE

The analysis of the e ect of high-energy protons of space radiation on the onboard electronics of the spacecraft is carried out. It is shown that protons can cause nuclear reactions with atomic nuclei of electronics material. The residual nuclei formed as a result of a nuclear reaction have su ciently high energy to cross the sensitive areas of several bits of electronics, and the high ionizing ability of nuclear fragments allows generating an excess charge of carriers exceeding the critical charge for the failure to occur simultaneously in several bits of the electronic device.

Comparative Study-Based Data-Driven Models for Lithium-Ion Battery State-of-Charge Estimation

Batteries have been considered a key element in several applications, ranging from grid-scale storage systems through electric vehicles to daily-use small-scale electronic devices. However, excessive charging and discharging will impair their capabilities and could cause their applications to fail catastrophically. Among several diagnostic indices, state-of-charge estimation is essential for evaluating a battery’s capabilities. Various approaches have been introduced to reach this target, including white, gray, and black box or data-driven battery models. The main objective of this work is to provide an extensive comparison of currently highly utilized machine learning-based estimation techniques. The paper thoroughly investigates these models’ architectures, computational burdens, advantages, drawbacks, and robustness validation. The evaluation’s main criteria were based on measurements recorded under various operating conditions at the Energy Systems Research Laboratory (ESRL) at FIU for the eFlex 52.8 V/5.4 kWh lithium iron phosphate battery pack. The primary outcome of this research is that, while the random forest regression (RFR) model emerges as the most effective tool for SoC estimation in lithium-ion batteries, there is potential to enhance the performance of simpler models through strategic adjustments and optimizations. Additionally, the choice of model ultimately depends on the specific requirements of the task at hand, balancing the need for accuracy with the complexity and computational resources available and how it can be merged with other SoC estimation approaches to achieve high precision.

Trends in Medicare Submitted Charges to Allowed Payment Ratios for Ophthalmology Services.

Many physicians charge more than the Medicare insurance program pays. Current charge-to-payment ratios in ophthalmology and trends over the years are unknown. In this work, we examined physician charge-to-payment ratios in ophthalmology across procedures and consultations. We utilized data from 100% final-action physician/supplier Part B Medicare fee-for-service (FFS) population from 2015 to 2020. We retrieved data on ophthalmic procedures and consultations, both facility-based and non-facility-based, conducted by ≥ 50 ophthalmologists. We analyzed median charge-to-payment ratios, which were calculated as submitted charges divided by the Medicare-allowed payments, between ophthalmic procedures and consultations to assess for trends over the study period. We find that the median charge-to-payment ratio for all current procedural terminology (CPT) codes in 2020 was 2.23 (Interquartile range (IQR): 1.54-3.27) as compared to 2.00 (IQR: 1.39-2.92) in 2015, an overall 2.76% average annual growth rate from 2015-2020. For ophthalmic procedures, the median charge-to-payment ratio in 2020 was 3.03 (IQR: 2.13-4.41) compared to 2.79 (IQR: 1.96-3.97) in 2015, corresponding to a 2.01% AAGR from 2015-2020. For consultations, those rates were 2.06 (IQR: 1.48-2.96), 1.85 (IQR: 1.33-2.59), and 2.71%, respectively. We found that the submitted charge-to-Medicare payment ratios among ophthalmic procedures and consultations have steadily increased since 2015. However, there was a relatively low rate of excess charges for ophthalmology services compared to other surgical-based specialties with minimal variation among providers.

Beyond Limits: A Brief Exploration of Fault Detection and Balancing in Lithium-ion Battery Technology

The process of achieving balance among sequentially connected cells is crucial to prevent excessive charging or discharging, and it also improves the overall energy capacity. This article discusses various algorithms created for equalizing cell charge within a battery management system (BMS). Proper cell balancing is indispensable for upkeeping lithium-ion battery (LiB) packs. Within the BMS, identifying faults is of utmost importance. This encompasses detecting, isolating, and estimating faults. To prevent batteries from operating in unsafe ranges, it is vital to ensure the accurate functioning of current, voltage, and temperature sensors. Accurate fault diagnosis is pivotal for the optimal operation of battery management systems. In the context of electric vehicle battery management systems, precise measurement of current, voltage, and temperature is greatly relied upon to estimate the State of Charge (SOC) and overall battery health. Swiftly identifying early failures can mitigate safety hazards and minimize damage. Nevertheless, effectively pinpointing these initial failures using genuine operational data from electric vehicles remains a intricate task. This paper presents an analysis of different algorithms for detecting balancing-related faults, covering both methods based on models and those not reliant on models. The strengths and weaknesses of the evaluated algorithms, along with upcoming challenges in the realm of balancing and fault detection for LiBs, are also discussed in this document.

Cost-Effective and Scalable Approach to EV Battery Management: MOSFET-Based Passive Cell Balancing

Cell balancing is crucial for preserving battery life and protecting battery cells in order to guarantee the safe and dependable functioning of LiFePo4 batteries on electric vehicles. Because passive cell balancing is inexpensive and simple to perform, BMS routinely uses it. In the passive cell balancing procedure, resistors are used as the balancing element to eliminate excess charge in the battery. Although resistors are inefficient when used with little cells, they are necessary when using large capacity batteries. The internal resistance of MOSFETs, which is utilized as a balancing element, allows for efficient cell balancing. The need for extra balancing components is eliminated by utilizing the MOSFET's intrinsic resistance. The current through the resistance is decreased hence the power losses are minimized and the heat dissipation is also reduced thus, the battery pack temperature is also maintained in the nominal value which decreases the danger of battery damage due to temperature.

Effective interaction between guest charges immersed in 2D jellium

The model under study is an infinite 2D jellium of pointlike particles with elementary charge e, interacting via the logarithmic potential and in thermal equilibrium at the inverse temperature β. Two cases of the coupling constant Γ≡βe2 are considered: the Debye–Hückel limit Γ→0 and the free-fermion point Γ=2 . In the most general formulation, two guest particles, the one with charge qe (the valence q being an arbitrary integer) and the hard core of radius σ > 0 and the pointlike one with elementary charge e, are immersed in the bulk of the jellium at distance d⩾σ . Two problems are of interest: the asymptotic large-distance behavior of the excess charge density induced in the jellium and the effective interaction between the guest particles. Technically, the induced charge density and the effective interaction are expressed in terms of multi-particle correlations of the pure (translationally invariant) jellium system. It is shown that the separation form of the induced charge density onto its radial and angle parts, observed previously in the limit Γ→0 , is not reproduced at the coupling Γ=2 . Based on an exact expression for the effective interaction between guest particles at Γ=2 , oppositely ( q=0,−1,−2,… ) charged guest particles always attract one another while likely ( q=1,2,… ) charged guest particles repeal one another up to a certain distance d between them and then the mutual attraction takes place up to asymptotically large (finite) distances.

Less is more: An oxyfluoride garnet broadband cyan-green phosphor towards highly efficient full-spectrum WLEDs

Full-spectrum lighting has become the development direction for human-centric illumination. However, the reabsorption effect caused by cyan, green and yellow multiple-phosphor packaging leads to low luminous efficiency. In this work, a broadband cyan-green phosphor is proposed to replace the cyan and yellow phosphors for highly efficient and thermally robust full-spectrum WLEDs. A new family of oxyfluoride garnet phosphors Lu2QMg2Al3O9F3: Ce3+ (Q = Ca, Sr, Ba) has been developed by incorporating F- into the classic LuAG: Ce3+ green phosphor. The excess charge was compensated by substituting trivalent Lu3+ and Al3+ with divalent alkaline earth element. The low covalency and phonon energy of fluorine-containing system endow these serial phosphors with efficient and thermally stable blue-shifted emission. The representative Lu2SrMg2Al3O9F3: Ce3+ exhibits a broadband cyan-green emission peaked at 513 nm with a 105 nm FWHM. Furthermore, outstanding quantum efficiency (88.4%) and thermal stability (94.3% @ 423 K) were achieved. This oxyfluoride phosphor was packaged with red phosphor without cyan phosphor on a blue chip. The obtained WLEDs show an excellent color rendering index (Ra = 96.8) with luminous efficiency (LE = 106 lm/W). This research might pave a promising avenue for the development of next-generation full-spectrum lighting.

X-rays, electrons, and neutrons as probes of atomic matter

X-rays, electrons, and neutrons probe different properties of matter. X-rays feel electron density (ED). Electrons sense the electrostatic potential (ESP) of electrons and nuclei. Neutrons are sensitive to nuclear coherent scattering length (NCSL). While NCSL maps are widely understood to be different, ED and ESP maps are tacitly assumed to be similar. Here, I show that the belief in ED and ESP map equivalence is mistaken, but contains a grain of truth. Using density functional theory (DFT), the Bethe-Mott (BM) relation, and the Thomas-Fermi (TF) and Cromer-Mann (CM) atomic models, I show that ED and ESP maps are indeed more similar to each other than to NCSL maps. Nevertheless, peak and integrated map values depend differently on the atomic order number and on the contributions from electrons in the inner and outer CM shells. ED and ESP maps also differ in the sign and relative magnitude of excess charge effects.

Janus molybdenum di-chalcogenides based van der Waals bilayers for supercapacitor electrode design- effects of interlayer stacking orientations on quantum capacitance

In this work, for the first time, the quantum capacitance of an artificial two-dimensional (2D) material system based on van der Waals (vdW) bilayer heterostructures of Janus Molybdenum Di-chalcogenides, MoXY (X≠Y, X/YS, Se, Te) have been extensively investigated for electrode design of electrical double-layer (EDL) supercapacitor. The effects of different interlayer stacking orientations on local charge distribution, interlayer charge transfer, energy band structure, and density of states (DOS) have been comprehensively analyzed and correlated with the excess charge density and quantum capacitance variation with local electrode potential. Furthermore, the total capacitance reduction with respect to EDL capacitance has been analyzed over a wide range of EDL capacitance, and the performance of vdW Janus bilayers has been systematically benchmarked against the natural monolayers/bilayers and Janus monolayers of Molybdenum Di-chalcogenides. The results demonstrate that the large interlayer charge transfer induced built-in interlayer electric field significantly reduces the energy band gap of vdW Janus bilayers for S–Te and Se–Te interlayer stacking, thus leading to a significantly superior quantum capacitance. Finally, the favorable valley-dependent effective mass and band-degeneracy in MoSTe/MoSeTe have greatly enhanced quantum capacitance in S–Te and Se–Te stacking, rendering these bilayers a highly attractive candidate for supercapacitor electrode design.

Observational features of charge distribution in Earth’s inner magnetosphere

Understanding the motion of charged particles in the electromagnetic field in the inner magnetosphere is essential for space science and space weather. Charge accumulation can occur due to the dipole magnetic and convective electric fields in this region. However, until the recent Magnetospheric Multiscale (MMS) mission, there were few means to detect charge distribution in situ. We report unambiguous in situ observation of the spatial distribution of the excess charge density in the inner magnetosphere by the MMS mission. We find that a positive (negative) charge accumulates in the dusk (dawn) side inner magnetospheres, which is contrary to the long assumed overall quasi-neutrality of space plasma. These observations and results offer insight into magnetosphere–ionosphere coupling.

Electron transfer-mediated synergistic nonlinear optical response in the Agn@C18 (n = 4–6) complexes: A DFT study on the electronic structures and optical characteristics

Seeking highly efficient and stable non-linear optical (NLO) materials is crucial yet challenging, given their promising applications in laser diodes and photovoltaics. In this study, we employ the excess electron and charge transfer strategies to theoretically design three novel complexes, namely Agn@C18 (n = 4–6), by adsorbing silver clusters onto the cyclo[18]carbon ring (C18). Our aim is to investigate the NLO characteristics of these complexes using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The results reveal that the adsorption of Ag clusters onto C18 leads to a decrease in excitation energy and an increase in dipole moment and oscillator strengths, thereby significantly enhancing the hyperpolarizability of the complexes. Strikingly, among all these complexes, Ag6@C18 exhibits the highest first hyperpolarizability value of approximately 109496.2620 au calculated at the B3LYP/cc-PVDZ-pp level of theory, which is about 1.3 × 106 times higher than that of pure C18. This finding validates the effectiveness of the proposed strategies in enhancing the NLO response of the species. Moreover, the calculated UV–Vis absorption spectrum demonstrates that the Agn@C18 complexes with excess electrons exhibit absorption at longer wavelengths (ranging from 385 to 731 nm) compared to C18. In addition, the stability, chemical bonding, and charge transfer characteristics of the Agn@C18 (n = 4–6) complexes were also discussed. These findings highlight the potential of these complexes for the development of highly efficient NLO devices.

A Novel Framework Interweaving in Mesoporous AlPO4 and Its Function in CO2 Decomposition

Molecular sieves are reported with isomorphous substitution by various metal ions. In this article, interweaving between tetrahedral framework of AlPO4 and the octahedral framework of CoO to produce a novel framework material is investigated; it is named as “Kankarlite” (CoO–AlPO4‐4). It is characterized by X‐ray diffraction (XRD), Fourier transform infrared, Brunauer–Emmett–Teller (BET), UV‐Vis analysis, thermogravimetric analysis (TGA), temperature programmed desorption (TPD) analysis, and transmission electron microscopy. The special feature of the catalyst is that it has two frameworks that are interweaved together to form a novel framework, which is proved by XRD and the crystal structure is drawn by VESTA software. In CoO framework, oxygen has three coordinations, which is proved by crystal structure. An excess negative charge appears on oxygen, creating an oxyanion. The TPD is also proved the oxyanion formation. This oxyanion is responsible for decomposing CO2 with high selectivity and conversion. The AlPO4 framework's function is to create mesopores in the catalyst. The TGA and UV‐Vis analyses prove the interweaving between two frameworks. The BET analysis proves that the Kankarlite has a pore size of 4 nm.

Accelerated Degradation of FAPbI3 Perovskite by Excess Charge Carriers and Humidity

Excess charge carriers in metal halide perovskite layer have been known to accelerate degradation of the film and devices to cause poor operational stability of perovskite solar cells (PSCs). While mechanisms for such degradation have been predominantly studied for methylammonium‐based perovskites, effects of excess charge carriers and their interplays with other degradation causes are barely studied for widely used formamidinium‐based perovskites. Herein, a possible decomposition mechanism of the formamidinium lead tri‐iodide (FAPbI3) perovskite in the presence of excess charge under different humidity levels is investigated. The operating condition with excessive charges is simulated by placing half devices with either electron‐transporting layer (ETL) or hole‐transporting layer (HTL) under 1 sun illumination. FAPbI3 in contact with ETL degrades more rapidly than the one with HTL, which is attributed to excess hole charge carriers in the film. Under higher humidity, the synergetic effect of excess charge carriers and humidity is found and thus degradation pathway and kinetics are strongly dependent on the humidity level. The fundamental understanding of degradation pathways for formamidinium perovskites should provide a useful insight toward the development of efficient and operationally stable PSCs toward practical usage.

Electrical environment can be altered at 1 km distances from high voltage power lines.

High voltage powerlines emit electrical charges into the atmosphere which can then attach to aerosols. This space charge above ground can be measured directly using ion spectrometers or indirectly through perturbations of the Earth’s potential gradient using field mills. Several publications are reviewed to find evidence of aerosol charging at a distance from power lines. Field measurements of charge state near to high voltage power lines selected due to their high emissions of ions measured a small positive enhancement of electrical charge on aerosols at distances greater than 300 m, corresponding to a transit time of up to 400 s A quasi one-dimensional model of ion-aerosol interactions from a high voltage powerlines found that the addition of new ions to an aerosol population will result in those ions transferring charge to the aerosol which would then remain the dominant carrier of charge several hundred meters downwind. 10-min PG measurements from a fixed site measuring in 2008 compared measurements when the site was downwind of a 275 kV powerline to times with no wind and found evidence of space charge overhead through greater fields and variability at distances over 800 m These studies combined show evidence that the electrical environment near to power lines can be altered beyond 1 km from AC high voltage power lines, with excess charges likely to be concentrated on aerosol.

Local electroneutrality breakdown for electrolytes within varying-section nanopores

We determine the local charge dynamics of a z-z\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$z-z$$\\end{document} electrolyte embedded in a varying-section channel. By means of an expansion based on the length scale separation between the axial and transverse direction of the channel, we derive closed formulas for the local excess charge for both, dielectric and conducting walls, in 2D (planar geometry) as well as in 3D (cylindrical geometry). Our results show that, even at equilibrium, the local charge electroneutrality is broken whenever the section of the channel is not homogeneous for both dielectric and conducting walls as well as for 2D and 3D channels. Interestingly, even within our expansion, the local excess charge in the fluid can be comparable to the net charge on the walls. We critically discuss the onset of such local electroneutrality breakdown in particular with respect to the correction that it induces on the effective free energy profile experienced by tracer ions.Graphical abstract

First experimental evaluation of a high-resolution deep silicon photon-counting sensor.

Current photon-counting computed tomography detectors are limited to a pixel size of around 0.3 to 0.5mm due to excessive charge sharing degrading the dose efficiency and energy resolution as the pixels become smaller. In this work, we present measurements of a prototype photon-counting detector that leverages the charge sharing to reach a theoretical sub-pixel resolution in the order of . The goal of the study is to validate our Monte-Carlo simulation using measurements, enabling further development. We measure the channel response at the MAX IV Lab, in the DanMAX beamline, with a 35keV photon beam, and compare the measurements with a 2D Monte Carlo simulation combined with a charge transport model. Only a few channels on the prototype are connected to keep the number of wire bonds low. The measurements agree generally well with the simulations with the beam close to the electrodes but diverge as the beam is moved further away. The induced charge cloud signals also seem to increase linearly as the beam is moved away from the electrodes. The agreement between measurements and simulations indicates that the Monte-Carlo simulation can accurately model the channel response of the detector with the photon interactions close to the electrodes, which indicates that the unconnected electrodes introduce unwanted effects that need to be further explored. With the same Monte-Carlo simulation previously indicating a resolution of around with similar geometry, the results are promising that an ultra-high resolution detector is not far in the future.

Effective interception of redox mediator shuttle behavior for Li[sbnd]O2 battery by separator modification based on g-C3N4 doped with Co elements

The utilization of redox mediators (RMs) offers a promising solution to address the issue of excessive charging voltage resulting from the generation of lithium peroxide (Li2O2) at the cathode in lithium‑oxygen (LiO2) batteries. However, the effectiveness of RMs is significantly impeded by a crucial drawback commonly referred to as the “shuttle phenomenon.” This phenomenon involves the RMs not only participating in the decomposition of Li2O2 but also migrating to the anode, where it reacts with the Li metal. Consequently, the RMs experience inevitable degradation, resulting in a severely limited cycling life. To tackle this challenge, we propose a strategy on limiting the 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO) worked as RM to the cathodic side by modifying the separator with the g-C3N4 doping with Co (Co-C3N4). Through the adsorption of TEMPO onto the Co-C3N4, the modified separator efficiently captures the TEMPO thus suppresses the shuttle effect. As a result, the Li metal anode is effectively safeguarded, facilitating uninterrupted and prolonged operation of the rechargeable battery. A remarkable cycle life of up to 160 cycles for LiO2 batteries can be realized, thus demonstrating the successful implementation of our strategy.

Trends in Hospital Billing for Mastectomy and Breast Reconstruction Procedures from 2013 to 2020.

With greater acceptance of postmastectomy breast reconstruction (PMBR) as a safe and reliable treatment option, the role of plastic surgeons in breast cancer management continues to rise. As Medicare reimbursements for surgical procedures decline, hospitals may increase charges. Excessive markups can negatively affect uninsured and underinsured patients. We aimed to analyze mastectomy and breast reconstruction procedures to gain insights into recent trends in utilization and billing. We queried the 2013 to 2020 Medicare Provider Utilization and Payment Data with 14 Current Procedural Terminology (CPT) codes to collect service count numbers, hospital charges, and reimbursements. We calculated utilization (service counts per million female Medicare enrollees), weighted mean charges and reimbursements, and charge-to-reimbursement ratios (CRRs). We calculated total and annual percentage changes for the included CPT codes. Among the 14 CPT codes, 12 CPT codes (85.7%) with nonzero service counts were included. Utilization of mastectomy and breast reconstruction procedures decreased from 1,889 to 1,288 (-31.8%) procedures per million female Medicare beneficiaries from 2013 to 2020. While the utilization of immediate implant placements (CPT 19340) increased by 36.2%, the utilization of delayed implant placements (CPT 19342) decreased by 15.1%. Reimbursements for the included CPT codes changed minimally over time (-2.9%) but charges increased by 28.9%. These changes resulted in CRRs increasing from 3.3 to 4.4 (+33.3%) from 2013 to 2020. Free flap reconstructions (CPT 19364) had the highest CRRs throughout the study period, increasing from 7.0 in 2013 to 10.3 in 2020 (+47.1%). Our analysis of mastectomy and breast reconstruction procedures billed to Medicare Part B from 2013 to 2020 showed increasingly excessive procedural charges. Rises in hospital charges and CRRs may limit uninsured and underinsured patients from accessing necessary care for breast cancer management. Legislations that monitor hospital markups for PMBR procedures may be considered by policymakers.

Atomistic origin of high grain boundary resistance in solid electrolyte lanthanum lithium titanate

Lanthanum lithium titanate is one of the promising electrolytes for solid-state lithium-ion batteries due to its high bulk ionic conductivity up to ∼10−3 S/cm. However, the practical application of this material has been bottlenecked by high grain boundary (GB) resistance, while the underlying mechanism is still under debate. Here we report a comprehensive study with direct evidence to reveal the origin of high GB resistance in La2/3–xLi3xTiO3 (LLTO). Atomic-scale observations via advanced scanning transmission electron microscopy show that the GBs are uniformly subject to subsurface segregation of La atoms to compensate for the excess surface charges. The La segregation leads to an abrupt decrease of charge carrier concentration neighboring GBs and hence is supposed to have deleterious effect on GB conductivity. The findings suggest a novel mechanism of space-charge-induced cation segregation, which shed lights on the intrinsic origin of low GB ionic conductivity in LLTO.

From Jekyll to Hyde and Beyond: Hydrogen's Multifaceted Role in Passivation, H-Induced Breakdown, and Charging of Amorphous Silicon Nitride.

In semiconductor devices, hydrogen has traditionally been viewed as a panacea for defects, being adept at neutralizing dangling bonds and consequently purging the related states from the band gap. With amorphous silicon nitride (a-Si3N4)─a material critical for electronic, optical, and mechanical applications─this belief holds true as hydrogen passivates both silicon and nitrogen dangling bonds. However, there is more to the story. Our density functional theory calculations unveil hydrogen's multifaceted role upon incorporation in a-Si3N4. On the "Jekyll" side, hydrogen atoms are indeed restorative, healing coordination defects in a-Si3N4. However, "Hyde" emerges as hydrogen induces Si-N bond breaking, particularly in strained regions of the amorphous network. Beyond these dual roles, our study reveals an intricate balance between hydrogen defect centers and intrinsic charge traps that already exist in pristine a-Si3N4: the excess charges provided by the H atoms result in charging of the a-Si3N4 dielectric layer.