Current Transfer Research Articles

A new PPP one-way timing approach via BDS-3 PPP-B2b and short-message communication service

In the realm of time-frequency, precise point positioning (PPP) technology has been widely used, the current PPP time transfer or timing necessitates network communication for data transmission, which consequently leads to a reduction in the reliability of PPP timing. Based on the BDS-3 PPP service (PPP-B2b) and the global short message communication (GSMC) service, this study proposes a novel PPP one-way timing method that is not subject to distance limitations or the requirements of network communication. Users can directly obtain the difference with UTC(k). Then, the proposed PPP timing method was validated using four stations equipped with external high-performance atomic clocks, based on a dataset of eight days. According to the findings, the suggested PPP one-way timing technique might reach a timing accuracy of roughly 0.5 ns in environments without a network. In terms of frequency stability, the proposed PPP timing method exhibits a stability of approximately 1.4 × 10−13 at 960 s and a stability of about 3 × 10−14 at 15360 s. Further, even under GSMC communication delays of 1 min, 5 min, and 10 min, the proposed PPP one-way timing accuracy can still achieve better than 0.5 ns.

Analysis of an operational trans-conductance amplifier with positive feedback

In this paper, we present an analysis of an operational trans-conductance amplifier (OTA) with two positive feedback. The direct current (DC) transfer function is obtained by analyzing the OTA using the drain current in the weak inversion region. The analysis results were verified through comparison with SPICE simulations, and the characteristics of the DC transfer function analysis for the OTA design are well matched with the simulation results. The designed OTA dissipates a low power of 41.4 nW, and features the slew rate is improved by 436% compared to a conventional OTA without two positive feedback. Additionally, a DC gain and a unity-gain bandwidth is improved by 36 dB and 6.7 times, respectively. The OTAs are designed for the 0.18 μm complementary metal–oxide–semiconductor (CMOS) process.

Current Transfer Length of Quasi-Isotropic Strand at Low Temperature

Current Transfer Length of Quasi-Isotropic Strand at Low Temperature

Analyses of nonequilibrium transport in atmospheric-pressure direct-current argon discharge under different modes

Abstract The key plasma parameters under different discharge modes, such as heavy-particle and electron temperatures, electron number density, and nonequilibrium volume of plasmas, play important roles in various applications of gas discharge plasmas. In this study, a self-consistent two-dimensional nonequilibrium fluid model coupled with an external circuit model is established to reveal the mechanisms related to the discharge modes, including the normal glow, abnormal glow, arc, and glow-to-arc transition modes, with an atmospheric-pressure direct-current (DC) argon discharge as a model plasma system. The modeling results show that, under different discharge modes, the most significant difference between the preceding four discharge modes lies in the current and energy transfer processes on the cathode side. On one hand, the current to the cathode surface is mainly delivered by the ions coming from the plasma column under the glow discharge mode due to the low temperature of the solid cathode, whereas the thermionic and secondary electrons emitted from the hot cathode surface play a very important role under the arc mode with a higher cathode surface temperature and higher ion flux toward the cathode. On the other hand, the energy transfer channel on the cathode side changes from mainly heating the solid cathode under the glow mode to simultaneously heating both the solid cathode and plasma column under the arc mode with an increase in the discharge current. Consequently, the power density in the cathode sheath (P c) was used as a key parameter for judging different discharge modes, and the range of (0.28–1.2) × 1012 W m−3 was determined as a critical window of P c corresponding to the glow-to-arc-mode transition for the atmospheric-pressure DC argon discharge, which was also verified by comparison with the experimental results in this study and the data in the previous literature.

Microbial Electrolysis Cells Based on a Bacterial Anode Encapsulated with a Dialysis Bag Including Graphite Particles.

One of the main barriers to MEC applicability is the bacterial anode. Usually, the bacterial anode contains non-exoelectrogenic bacteria that act as a physical barrier by settling on the anode surface and displacing the exoelectrogenic microorganisms. Those non-exoelectrogens can also compete with exoelectrogenic microorganisms for nutrients and reduce hydrogen production. In this study, the bacterial anode was encapsulated by a dialysis bag including suspended graphite particles to improve current transfer from the bacteria to the anode material. An anode encapsulated in a dialysis bag without graphite particles, and a bare anode, were used as controls. The MEC with the graphite-dialysis-bag anode was fed with artificial wastewater, leading to a current density, hydrogen production rate, and areal capacitance of 2.73 A·m-2, 134.13 F·m-2, and 7.6 × 10-2 m3·m-3·d-1, respectively. These were highest when compared to the MECs based on the dialysis-bag anode and bare anode (1.73 and 0.33 A·m-2, 82.50 and 13.75 F·m-2, 4.2 × 10-2 and 5.2 × 10-3 m3·m-3·d-1, respectively). The electrochemical impedance spectroscopy of the modified graphite-dialysis-bag anode showed the lowest charge transfer resistance of 35 Ω. The COD removal results on the 25th day were higher when the MEC based on the graphite-dialysis-bag anode was fed with Geobacter medium (53%) than when it was fed with artificial wastewater (40%). The coulombic efficiency of the MEC based on the graphite-dialysis-bag anode was 12% when was fed with Geobacter medium and 15% when was fed with artificial wastewater.

An online comprehensive health monitoring system for automotive auxiliary converter

Abstract As an essential part of the electronic system in electric vehicles (EVs), the automotive auxiliary converter (AAC) connects the batteries and burdens the auxiliary power supply. This paper mainly proposes an online comprehensive health monitoring system for AAC. Firstly, based on the control diagram of the LLC resonant converter, three critical components are emerging, including capacitor, optocoupler, and semiconductor. These components can partly reflect the operation condition of the output loop, feedback loop, and control link, respectively. Then the characteristics parameters of these three components, equivalent series resistance (ESR) of the capacitor, current transfer ratio (CTR) of the optocoupler, and on-resistance of the semiconductor jointly construct the three-dimensional health monitoring vector. Finally, the online monitoring accuracy is verified and the proposed system can thus effectively promote the operation and maintenance of AAC. Furthermore, the online health monitoring system enables a flexible expansion, which can be further customized into different kinds of power converters, showing high applicability and practicality.

Combining Supercapacitor and Energy Harvesting Devices with Magnets Integrated with Interfacial Materials for Efficient Current Transfer

Combining Supercapacitor and Energy Harvesting Devices with Magnets Integrated with Interfacial Materials for Efficient Current Transfer

Elucidating the local structure and electronic properties of a highly active overall alkaline water splitting NixCo1-xO/hollow carbon sphere catalyst

A NixCo1-xO/HCS catalyst with superior water-splitting is presented. High water-splitting reaction kinetics and enhanced durability were observed. The structure-function relationship was investigated with XPS, which demonstrated the presence of dominant Ni2+ and Co2+ species and a functionalized HCS support where nucleation of small metal oxide nanoparticles occurred. The PDF showed broadened Nickel/Cobalt-oxide bonds and expansion of the metal-metal pair distances. The alteration of the Metal-Oxide and Metal-Metal-Oxide bonds favored better HER and OER electrocatalysis, also as supported by DFT. EXAFS showed the existence of the bimetallic oxide catalyst and the stretching of the Ni–O bonds due to the coordination of the Ni–O with the Co. The composite exhibited higher activity and enhanced electrocatalytic mechanism towards water splitting through higher exchange current densities (0.615 and 0.886 mA cm−2) and low charge transfer resistance (14 and 10 Ω) respectively. Chronoamperometry proved the catalyst's stability during prolonged electrolysis.

0.35 V Subthreshold Bulk-Driven CMOS Second-Generation Current Conveyor

This study describes a high-performance second-generation Current Conveyor (CCII) operating at 0.35 V and achieving rail-to-rail operation at the Y terminal and class AB current drive at the X and Z terminals. The solution utilizes a low-voltage subthreshold bulk-driven CMOS OTA that was experimentally developed earlier, making systematic use of body terminals to improve small-signal and large-signal performance. The circuit has a high open-loop voltage gain and uses cascoded current mirror topologies, resulting in precise voltage and current transfer with bandwidths of 1.33 MHz and 2.13 MHz, respectively. The CCII offers a linear current drive up to 2.5 µA while consuming a total quiescent current of 2.86 µA (758 nA in the output branches), displaying one the highest figures of merit in terms of current utilization for sub 1 V solutions.

Interhospital Transfer of Patients With Acute Respiratory Failure in the United States: A Scoping Review.

Interhospital transfer of patients with acute respiratory failure (ARF) is relevant in the current landscape of critical care delivery. However, current transfer practices for patients with ARF are highly variable, poorly formalized, and lack evidence. We aim to synthesize the existing evidence, identify knowledge gaps, and highlight persisting questions related to interhospital transfer of patients with ARF. Ovid Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Embase, CINAHL Plus, and American Psychological Association. We included studies that evaluated or described hospital transfers of adult (age > 18) patients with ARF between January 2020 and 2024 conducted in the United States. Using predetermined search terms and strategies, a total of 3369 articles were found across all databases. After deduplication, 1748 abstracts were screened by authors with 45 articles that advanced to full-text review. This yielded 16 studies that fit our inclusion criteria. The studies were reviewed in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews by three authors. Included studies were mostly retrospective analyses of heterogeneous patients with various etiologies and severity of ARF. Overall, transferred patients were younger, had high severity of illness, and were more likely to have commercial insurance compared with nontransferred cohorts. There is a paucity of data examining why patients get transferred. Studies that retrospectively evaluated outcomes between transferred and nontransferred cohorts found no differences in mortality, although transferred patients have a longer length of stay. There is limited evidence to suggest that patients transferred early in their course have improved outcomes. Our scoping review highlights the sparse evidence and the urgent need for further research into understanding the complexity behind ARF transfers. Future studies should focus on defining best practices to inform clinical decision-making and improve downstream outcomes.

Growth of Carbon Nanofibers and Carbon Nanotubes by Chemical Vapour Deposition on Half-Heusler Alloys: A Computationally Driven Experimental Investigation.

The possibility of directly growing carbon nanofibers (CNFs) and carbon nanotubes (CNTs) on half-Heusler alloys by Chemical Vapour Deposition (CVD) is investigated for the first time, without using additional catalysts, since the half-Heusler alloys per se may function as catalytic substrates, according to the findings of the current study. As a carbon source, acetylene is used in the temperature range of 700-750 °C. The n-type half-Heusler compound Zr0.4Ti0.60.33Ni0.33Sn0.98Sb0.020.33 is utilized as the catalytic substrate. At first, a computational model is developed for the CVD reactor, aiming to optimize the experimental process design and setup. The experimental process conditions are simulated to investigate the reactive species concentrations within the reactor chamber and the activation of certain reactions. SEM analysis confirms the growth of CNFs with diameters ranging from 450 nm to 1 μm. Raman spectroscopy implies that the formed carbon structures resemble CNFs rather than CNTs, and that amorphous carbon also co-exists in the deposited samples. From the characterization results, it may be concluded that a short reaction time and a low acetylene flow rate lead to the formation of a uniform CNF coating on the surface of half-Heusler alloys. The purpose of depositing carbon nanostructures onto half-Heusler alloys is to improve the current transfer, generated from these thermoelectric compounds, by forming a conductive coating on their surface.

Transfer Stigma: Development of a Multi–Dimensional Scale for Community College Transfer Students

ABSTRACT Transfer stigma refers to a type of stigma associated with students’ transfer status and/or their community college background. It plays a significant role in post-transfer adjustment and may negatively impact post-transfer outcomes such as retention and obtaining a baccalaureate degree. This study focused on quantitatively measuring transfer stigma among transfer students attending a four-year institution. Drawing from previous studies, we developed a 13-item transfer stigma measure and included it in a transfer student survey. The survey data was collected from 450 current transfer students at a public, flagship four-year university in Louisiana. Through an exploratory factor analysis and a confirmatory factor analysis, we revealed a four-factor structure of transfer stigma measures: internalized self-stigma, perceptions about community colleges, lack of support, and perceived judgment. Subsequent statistical analyses examined group differences in the degree of transfer stigma across various transfer student subgroups defined by transfer type, gender, race/ethnicity, age, and major.

Wideband AC Voltage Standards

This article presents a critical review and comparison of constructions and metrological properties of contemporary wideband standards for AC voltage. It focuses on selected thermal voltage converters (TVCs) used in alternating current-direct current (AC-DC) transfer voltage standards and for the most precise measurements of AC voltages up to approximately 100 MHz. These devices serve as primary AC voltage standards at National Measurement Institutes (NMIs).

High-performance coaxial reversal rotational triboelectric nanogenerator based on charge pumping strategy driving tip high voltage breakdown

Triboelectric nanogenerator (TENG) serves as an effective method for harvesting mechanical energy from the surrounding environment. Nonetheless, its practical application is hindered by issues such as inadequate charge density and wear of friction surface materials. Here, a high-performance self-supplementing coaxial inverse triboelectric nanogenerator (HSCI-TENG) based on charge pumping supplementary strategy is presented, which operates in non-contact mode and increases surface charge density with almost no friction loss. The coaxial reversal design facilitates dual-speed rotation, resulting in a significant enhancement of the output current. Furthermore, an innovative approach was employed by affixing four layers of 0.06 mm thick PET film to the storage electrode, thereby augmenting the threshold of electrode charge storage and effectively mitigating the risk of electrode breakdown. At a rotation speed of 300 rpm, the peak-to-peak voltage, peak-to-peak current, and charge transfer of HSCI-TENG are 3340 V, 360 μA and 0.97 μC, respectively. Excellent stability is demonstrated through 10000 cycle tests on the output of HSCI-TENG. In particular, the maximum output power is 770 mW at a load resistance of 8×106 Ω. The high-performance HSCI-TENG has been proven to be a stable energy source driving high voltage breakdown sensor system. The tip high voltage breakdown exhibits high frequency and continuity, with 14 breakdowns occurring within 10 seconds. Besides, HSCI-TENG has potential to serve as an energy source for high-pressure sterilization, high-pressure dust removal, and water electrolysis systems.

Mixed convective viscous dissipative flow of Casson hybrid nanofluid with variable thermal conductivity at the stagnation zone of a rotating sphere

AbstractMixed convection flows across the revolving bodies have eminent applications in science and technology, such as fibre coating, polymer deposition, centrifugal blood pumps, rotatory machinery, and so forth. In the current work, magnetohydrodynamic (MHD) flow and heat transfer characteristics of Casson hybrid nanofluid (Ag/MgO as nanoparticles) over the rotating sphere at the stagnation zone are being studied. Moreover, an analysis of heat transmission is conducted by considering the influence of thermal radiation, temperature‐dependent thermal conductivity, magnetic field, and viscous dissipation. The relevant partial differential equations are reformed into ordinary differential equations by appropriate transformations, which are solved using the successive linearization method (SLM). The thermal field, velocity components in x and z directions, heat transfer rate, and skin friction coefficient are computed for various physical quantities like rotation parameter mixed convection parameter, radiation parameter, Eckert number, Casson parameter, magnetic parameter, variable thermal conductivity parameter, and so forth. The current findings align well with the literature in a limiting sense. Thermal enhancement in hybrid nanofluid is observed for the viscous dissipation parameter (Ec), thermal conductivity parameter (), and radiation parameter (Rd). The degree of heat transfer rises from 12.8% to 20% when the Casson parameter's value () increases. Also, a decrease of approximately 33% is depicted between the peak values of the velocity magnitude with an increase in rotation parameter.

Enhanced interlayer electron transfer by surface treatments in mixed-dimensional van der Waals semiconductor heterostructures

We investigate the excitonic species in WS2 monolayers transferred onto III–V semiconductor substrates with different surface treatments. When the III–V substrates were covered with amorphous native oxides, negatively charged excitons dominated the spectral weight in low-temperature near-resonance photoluminescence (PL) measurements. However, when the native oxides of the III–V substrates were reduced, neutral excitons began to dominate the spectral weight, indicating a reduction in the electron density in the WS2 monolayers. The removal of the native oxides enhanced the electron transfer from the WS2 monolayer to the III–V substrate. In addition, an additional shoulder-like PL feature appeared ∼50 meV below the emission of neutral excitons, which can be attributed to the emission of localized excitons. When the III–V substrate surface was passivated by sulfur after the reduction of the native oxides, neutral excitons still dominated the spectral weight. However, the low-energy PL shoulder disappeared again, suggesting the effective delocalization of excitons through substrate surface passivation. Surface engineering of the semiconductor substrates for two-dimensional (2D) materials can provide a novel approach to control the carrier density of the 2D materials, implement deterministic carrier localization or delocalization for the 2D materials, and facilitate the interlayer transfer of charge, spin, and valley currents. These findings open the avenue for novel device concepts and phenomena in mixed-dimensional semiconductor heterostructures.

Comparing costs and climate impacts of various electric vehicle charging systems across the United States

The seamless adoption of electric vehicles (EVs) in the United States necessitates the development of extensive and effective charging infrastructure. Various charging systems have been proposed, including Direct Current Fast Charging, Battery Swapping, and Dynamic Wireless Power Transfer. While many studies have evaluated the charging costs and greenhouse gas (GHG) intensity of EVs, a comprehensive analysis comparing these systems and their implications across vehicle categories remains unexplored. This study compares the total cost of ownership (TCO) and GHG-intensity of EVs using these charging systems. Based on nationwide infrastructure deployment simulations, the change to TCO from adopting EVs varies by scenario, vehicle category, and location, with local fuel prices, electricity prices, and traffic volumes dramatically impacting results. Further, EV GHG-intensity depends on local electricity mixes and infrastructure utilizations. This research highlights the responsiveness of EV benefits resulting from technology advancements, deployment decisions, and policymaking.

From Fundamental Interfacial Reaction Kinetics to Macroscopic Current–Voltage Characteristics: Case Study of Solid Acid Fuel Cell Limitations and Possibilities

AbstractThe unique properties of solid acid electrolytes, in particular CsH2PO4, are in many ways ideal for fuel cell operation. However, the technology is constrained by high cathode overpotentials. Here a simplified cathode geometry is employed to obtain the fundamental electrochemical parameters (exchange current density and charge transfer coefficient) describing the oxygen reduction reaction (ORR) at the CsH2PO4‐Pt‐gas interface. The parameters are incorporated into a 1D model of the voltage–current characteristics of realistic SAFC cathodes, which reproduced the measured polarization behavior of such cathodes without recourse to fitting adjustable parameters. Following this validation, the model is utilized to evaluate the impact of changes to cathode properties, microstructure, and operating conditions. Of these, the charge transfer coefficient, measured to have a value of ≈0.6 for ORR on Pt in the SAFC cathode environment, is found to have the greatest impact on power output. Nevertheless, even without material modifications, a combination of microstructural and operational modifications are identified with projected performance metrics meeting Department of Energy targets (0.8 V at 300 mA cm−2, and peak power density of 1 W cm−2), albeit at high Pt loadings. However, the analysis indicates that truly meaningful advances will likely necessitate the discovery of alternative ORR catalysts.

Implications of homogeneous–heterogeneous reactions, Hall current, and dissipative radiative heat transfer on MHD Casson fluid flow over a bi-directional stretching sheet

This consideration highlights a numerical analysis of the unsteady three-dimensional flow of a Casson fluid over a stretching surface extending in its plane considering the effects of Hall current, thermal radiation, homogeneous–heterogeneous reactions, viscous dissipations, and an external magnetic field. The fluid flow in the region is developed due to the stretching of the sheet along the two directions in its plane. Two different species are present in the flow region which are taking part in homogeneous and heterogeneous reactions. Fluid velocity, thermal, and mass transportation are expressed mathematically using a set of nonlinear partial differential equations ( PDEs ) along with suitable boundary conditions. By using the appropriate similarity transformations, these equations ( PDEs ) that reflect the mathematical model are transformed into a set of nonlinear ordinary differential equations ( ODEs ) . The transformed equations ( ODEs ) were further solved numerically utilizing the bvp 4 c solver. The comprehensive study regarding the impacts of flow parameters on velocities, temperature, and concentration is also presented with graphs. It is observed that the thermal boundary layer is enhanced with an increment in the Hall current parameter, magnetic parameter, and thermal radiation. Moreover, with an increase in homogeneous-heterogeneous reaction parameters, mass transportation decreases. The physical quantities such as the coefficient of skin friction and coefficient of heat and mass transfer are also obtained numerically. Moreover, an appropriate agreement is obtained on comparing the current results with previously published results.

Optimized preparation of Ni-Febm bimetallic particles by ball milling NiSO4 and iron powder for efficient removal of triclosan

The excessive usage and emissions of triclosan (TCS) pose a serious threat to aquatic environments. Iron-based bimetallic particles (Pd/Fe, Ni/Fe, and Cu/Fe, etc.) were widely used for the degradation of chlorophenol pollutants. This study proposed a novel synthesis method for the preparation of Ni/Fe bimetallic particles (Ni-Febm) by ball milling microscale zero valent iron ZVI (mZVI) and NiSO4. Ball-milling conditions such as ball-milling time, ball-milling speed and ball-to-powder ratio were optimized to prepare high activity Ni-Febm bimetallic particles. During the ball-milling process, Ni2+ was reduced to Ni0 and formed a coupled structure with ZVI. The amount of Ni0 on ZVI significantly affected the activity of Ni-Febm bimetallic particles. The highest activity Ni-Febm bimetallic particles with Ni/Fe ratio of 0.03 were synthesized under optimized conditions, which could remove 86.56% of TCS (10 μM) in aerobic aqueous solution within 60 min. In addition, higher particle dosage, lower pH condition and higher reaction temperature were more conducive for TCS degradation. The higher corrosion current and lower electron transfer impedance of Ni-Febm bimetallic particles were the main reasons for its high activity. The hydrogen atom (•H) on the surface of Ni-Febm bimetallic particles was mainly contributed to the removal of TCS, as reductive transformation products of TCS were detected by LC-TOF-MS. Notably, a small amount of oxidation products were discovered. The total dechlorination rate of TCS was calculated to be 39.67%. After eight reaction cycles, the residual Ni-Febm bimetallic particles could still degrade 28.34% of TCS within 6 h. Low Ni2+ leaching during reaction indicated that Ni-Febm bimetallic particles did not pose potential environmental risks. The prepared environmental-friendly Ni-Febm bimetallic particles with high activity have great potential in the degradation of other chlorinated organic compounds in wastewater.