External Supply Voltage Research Articles

Model-based development of cell voltage control system for modified bio-electro-Fenton process

A modified bio-electro-Fenton (M−BEF) process with a cell voltage control system that improves the efficiency of organic removal and energy savings is demonstrated. The M−BEF process can accomplish bioelectricity generation, H2O2 production, and the Fenton reaction in a continuous-flow reactor. During synthetic wastewater treatment containing biodegradable (glucose) and recalcitrant (biphenyl) organic matter, the effluent chemical oxygen demand (COD) concentration was maintained between 2 and 6 mg L-1. To investigate the impact of different operating schemes on energy usage, model-based design (MBD) modeling and simulations were performed, which showed that COD removal efficiency without an external voltage supply was unstable at < 70 %. The automatic cell voltage control system saved 90 % of the power compared to the continuous cell voltage supply system. Further testing on more environmental samples and pollutants will enable real-time optimization of supplied power and wastewater treatment using the cell voltage control system.

Investigation of electrothermal properties of indium-tin-oxide thin films

Transparent conductive oxide (TCO) thin films are highly sought-after for their unique characteristics of conducting electricity and transmitting visible light, making them ideal conductive coating materials for electronic devices. We carried out a comprehensive analysis of the deposition, optical, electrical, and structural properties of ITO and Ag/ITO thin films on glass substrates in this study. The weight ratio of the deposited metals was 1:10, 2:10, and 4:10[Formula: see text]wt.% (Sn:In) for ITO films and 1:1:10[Formula: see text]wt.% (Ag:Sn:In) for Ag–ITO film. The films were annealed at 300°C using a program controller furnace. We employed infrared cameras to analyze the surface temperature profiles of these thin films under external voltage supply. We also investigated the resistivity behavior of both ITO and Ag–ITO films, analyzing them with regard to Mott’s variable range hopping (VRH) model and the fluctuation-induced tunneling model. Scanning electron microscope images revealed that adding Ag increased the grain size of ITO thin films. The average grain size for ITO thin film was determined as 186[Formula: see text]nm, while it was found to be 270[Formula: see text]nm for Ag–ITO thin film. Furthermore, incorporating Ag into the ITO thin film resulted in a reduction of 21.5% in transmittance over the complete visible range of the electromagnetic spectrum when compared to the ITO thin film without Ag as measured by ultra-visible spectrophotometer. The figure of merit was obtained as [Formula: see text] for ITO and [Formula: see text] for Ag–ITO thin films. However, the resistance of the ITO thin film was calculated to be 9.58[Formula: see text]k[Formula: see text], while that of the Ag–ITO film was found to be 6.99[Formula: see text]k[Formula: see text]. The ITO thin film that included Ag exhibited a lower electrical resistivity due to the larger grain size caused by doped Ag atoms in the structure, leading to less electron scattering at the grain boundaries and a resulting decrease in resistivity as determined by four-point probe system. Thermal imaging camera measurements revealed that the surface temperature of the ITO thin film decreased with the addition of Ag under high voltage application, but not under low voltage. When a voltage of 350[Formula: see text]V and 250[Formula: see text]V was applied to the thin films, the ITO film exhibited a surface temperature of 73.9°C and 50.4°C, whereas under identical conditions, the Ag–ITO film showed a surface temperature of 62°C and 44.1°C, respectively. Furthermore, both films exhibited exponentially increasing surface temperature behavior under a certain voltage, suggesting that they have potential for transparent heaters and high-voltage/low-current applications.

A next-generation transistor with low supply voltage operation constructed based on 2D materials' metal-semiconductor phase transition.

Power dissipation, a fundamental limitation for realizing high-performance electronic devices, may be effectively reduced by an external supply voltage. However, a small supply voltage simultaneously brings another serious challenge, that is, a remarkable device inability in transistors. To deal with this issue, we propose a new transistor design based on the metal-semiconductor phase transition in a AsGeC3 monolayer, which provides a switching mechanism of band-to-band tunneling at on- and off-states by gate-voltage modulation. Our first-principles calculations uncover that the monolayer AsGeC3 field-effect transistors (FETs) with gate lengths of 5, 4, and 3 nm may meet well the requirements for on-state current (Ion), power dissipation (PDP), and delay period (τ) as outlined by the International Technology Roadmap for Semiconductors (ITRS) in 2013 to achieve higher performance by the year 2028. Importantly, high performances are achieved only under a very low supply voltage (VDD = 0.05/0.10 V). Significantly, the AsGeC3 FETs exhibit remarkably lower values of both PDP and τ than those of nearly all the transistors reported up to date. These novel 2D metal-semiconductor phase transition-based FETs open up a new door for designing next-generation low-power electronic devices.

In2O3/Bi2S3 S-scheme Heterojunction-Driven Molecularly Imprinted Photoelectrochemical Sensor for Ultrasensitive Detection of Florfenicol.

Florfenicol (FF) raises significant human health and environmental concerns due to its toxicity to the hematology system and the potential spread of antibiotic-resistant genes. Here, a highly sensitive molecularly imprinted photoelectrochemical (PEC) sensor, featuring an In2O3/Bi2S3 S-scheme heterojunction, is proposed to detect FF without an external voltage supply. Compared with conventional II-type heterojunctions, S-scheme heterojunctions efficiently promote carrier separation and enhance the redox capability of the photocatalytic system. This allows more dissolved O2 and H2O molecules to participate in the redox reaction, resulting in an amplified and stabilized photocurrent response. The electron transfer in the S-scheme heterojunction is confirmed via electron spin resonance (ESR). With the molecular imprinting technique, this PEC platform exhibits exceptional selectivity, wide linear range (1.0 × 10-4-1.0 × 104 ng mL-1), low detection limit (6.4 × 10-5 ng mL-1), and applicability in real milk and chicken samples. This work not only showcases a PEC platform for accurately and portably detecting drugs but also proposes a viable approach for designing S-scheme heterojunctions in sensing analysis.

A High Crosstalk Suppression SiC MOSFET Gate Driver

Fast switching speeds and high switching frequencies bring serious crosstalk problems in SiC MOSFET applications. In this paper, we design a SiC MOSFET gate driver with high crosstalk suppression capability by using a multi-level drive and active Miller clamp technology. In the design, an auxiliary branch is introduced to control the source potential of the SiC MOSFET to achieve multilevel driving. The branch has a simple structure, simple control logic, no external negative voltage supply, and adjustable negative output voltage. The proposed SiC MOSFET gate driver was designed using the Central Semiconductor Manufacturing Corporation (CSMC) 0.8 μm BCD high voltage process. The designed SiC MOSFET gate driver has an area of 2967 μm × 3180 μm. The simulation verification model is based on Wolfspeed’s SiC MOSFET product C3M0075120D. Post-layout simulation results show that a SiC MOSFET gate driver with a crosstalk suppression capability of over 150 V/ns is obtained, which can reliably drive SiC MOSFET power devices.

Anode Biofilm Formation With Applied External Voltage

Background. The formation of an exoelectrogenic biofilm in a microbial fuel cell (MFC) is an important stage, because it affects later on current generation by the system. The fermented residue after methanogenesis as an inoculum contains not only exoelectrogenic microorganisms, but also methanogens, which reduce the productivity of MFC. The use of current allows the formation of a biofilm enriched with exoelectrogenic microorganisms. Objective. The purpose of our study was to establish the parameters of MFC under periodic application of external voltage. Methods. A two-chamber H-type MFC with a salt bridge between the chambers was used for the study. The anolyte was stirred with a magnetic stirrer for 4 h a day and a 3V voltage was simultaneously applied to create selective conditions for exoelectrogenic biofilm growth. Results. The application of external voltage stimulated the increase in the current and voltage of the MFC. With the periodic application of an external voltage, the MFC current increased to 788 ± 40 mA for the MFC with a resistor and without load. After disconnection and discharge, the MFC current dropped to 189 ± 10 mA for the MFC without load and to 154 ± 8 mA for the MFC with a resistor, respectively. Under the conditions of MFC operation without applying external voltage, the current was 960 ± 50 mA for MFC with an open circuit and 672 ± 35 mA for MFC with a closed circuit when a resistor is connected. For all MFC, the current gradually decreased over time. MFC demonstrated capacitive behaviour: after accumulating charge for 4 h, a discharge from 622 ± 30 mV to 462 ± 23 mV was observed. Microscopy showed fouling of the anode. Since the fermented residue after methanogenesis is mixed consortium, the anodic biofilm was also mixed consortium enriched with different species of exoelectrogens. Conclusions. Periodic application of external voltage allowed to increase the current by 17% and double the voltage compared to MFC without external voltage supply. However, after disconnecting the external voltage source, the MFC gradually discharged, that is, the current and voltage decreased. The maximum value of the current of the MFC with an open circuit was 22% more than the MFC with a closed circuit.

Self-powered photoelectrochemical aptasensor based on hollow tubular g-C3N4/Bi/BiVO4 for tobramycin detection

A highly sensitive photoelectrochemical aptasensor based on phosphorus-doped hollow tubular g-C3N4/Bi/BiVO4 (PT-C3N4/Bi/BiVO4) for tobramycin (TOB) detecting was developed. This aptasensor is a self-powered sensing system which could generate the electrical output under visible light irradiation with no external voltage supply. Based on the surface plasmon resonance (SPR) effect and unique hollow tubular structure of PT-C3N4/Bi/BiVO4, the PEC aptasensor exhibited an enhanced photocurrent and favorably specific response to TOB. Under the optimized conditions, the sensitive aptasensor presented a wider linearity to TOB in the range of 0.01–50 ng mL−1 with a low detection limit of 4.27 pg mL−1. This sensor also displayed a satisfying photoelectrochemical performance with optimistic selectivity and stability. In addition, the proposed aptasensor was successfully applied to the detection of TOB in river water and milk samples.

A Soft Variable-Area Electrical-Double-Layer Energy Harvester.

The technological promise of soft devices-wearable electronics, implantables, soft robotics, sensors-has accelerated the demand for deformable energy sources. Devices that can convert mechanical energy to electrical energy can enable self-powered, tetherless, and sustainable devices. This work presents a completely soft and stretchable (>400% strain) energy harvester based on variable-area electrical-double-layer (EDL) capacitors (≈40µFcm-2 ). Mechanically varying the EDL area, and thus the capacitance, disrupts equilibrium and generates a driving force for charge movement through an external circuit. Prior EDL capacitors varied the contact area by depressing water droplets between rigid electrodes. In contrast, here, the harvester consists of liquid-metal electrodes encased in a hydrogel. Deforming the device by ≈25% strain generates a power density ≈0.5mWm-2 . This unconventional approach is attractive because: (1) it does not need an external voltage supply to provide charge; (2) the electrodes themselves deform; and (3) it can work under various modes of deformation such as pressing, stretching, bending, and twisting. The unique ability of the harvester to operate underwater shows promising applications in wearables that contact sweat, underwater sensing, and blue energy harvesting.

A novel high-accuracy platinum resistance flexible temperature chain for polar temperature field measurement

In order to effectively improve the accuracy of temperature measurement in the low temperature environment of the polar ice sheet, we designed a multi-point platinum resistance flexible temperature chain based on Pt1000, which has the advantages of low temperature resistance, low power consumption and high accuracy. The temperature chain consists of a master and multiple slaves. The master is used to read the entire temperature chain's data and make data exchange with the external equipment. The slave is used to collect and upload temperature data. RS485 bus communication is used between the master and slaves. The slave circuit directly measures the ratio of the bridge output voltage to the bridge input voltage to calculate the final temperature value, so the measurement accuracy is not affected by the fluctuation of the external power supply voltage. After the temperature measurement unit of each slave is calibrated using the least square method, when the temperature is greater than 0̂C, the temperature measurement error does not exceed 0.00134̂C, and when the temperature is less than 0̂C, the error does not exceed 0.07235̂C. In addition, low temperature experiments indoor as well as field tests have shown that the overall reliability of the temperature chain is higher for simultaneous temperature measurement at multiple points in the low temperature environment, which is suitable for detecting the temperature field profile of glacial ice and snow in the polar environment.

Reverse battery model for anodic arc discharges near atmospheric pressure

In this study, the macroscopic electrical parameters of anodic arc discharges performed with solid carbon and molybdenum anodes are described in terms of an equivalent circuit. The proposed 1D model shows that the plasma volume behaves as a dissipative medium combined with self-generated voltage from the plasma sheaths. This model is tested by fitting virtual circuits of resistors and batteries to the measured voltage–current (V–I) characteristics representative of atmospheric arc processes (300 and 500 Torr He), resulting in the identification of two phenomena relevant for arc technology. First, steady DC arc experiments show that a minimal arc voltage (V0 ≈ 20–30 V) or threshold voltage is necessary to keep the plasma arc on. Second, we prove that pulsed arc discharges excited with rectangular current waveforms (1–5 Hz) are never extinguished but remain ignited during the inactive time of the pulse as long as the aforementioned threshold voltage is maintained. In summary, an atmospheric anodic arc discharge with solid electrodes consumes electrical power as a voltage source opposed to the external voltage supply together with a resistor that accounts for the plasma impedance. This approach permits us to estimate basic plasma parameters from simple electrical diagnostics, as well as to predict how power consumption is distributed within an anodic arc and to understand dynamics of arc plasmas excited by periodic signals.

Enrichment in Methane Content in Biogas By External Voltage Supply

The increment in the methane content has a major role to broaden the application of biogas. Enhancement of the methane-generating metabolism of microorganisms known as methanogens is required to increase the methane production. Research has shown that methanogens can use supplied voltage to acquire the electrons for the production of methane from CO2. In this process, methanogens reduce CO2 to CH4 utilizing electrons from externally supplied voltage on integrating with anaerobic digestion. Microbial electrochemical cells (MEC) was developed employing biocompatible fibrous graphite electrodes. Cow manure was assessed for the anaerobic digestion combined with MEC. The objectives of the study were to use manure waste and to enrich methane in biogas even at low temperature condition. The biogas produced contains mainly methane, hydrogen sulphide and carbon dioxide. The maximum gas production was at 37oC. However, biogas could be produced at 18oC with supply of 2V external power. There was found 65 times increment in biogas production with external power supply at 18oC. Besides methanogens, two other bacterial species identified were Serratia liquefaciens and Zoballella taiwanensis respectively. Keywords: Methane, biogas, methanogens, voltage, anaerobic digestion, microbial ecology

Analysis and Design of Ultra-Large Dynamic Range CMOS Transimpedance Amplifier With Automatically-Controlled Multi-Current-Bleeding Paths

In this paper, a fully-integrated transimpedance amplifier with ultra-large dynamic range and automatic gain control function is presented. By first deploying three AGC-controlled current paths in the low noise pre-amplifier, the transimpedance amplifier (TIA) can accommodate a significantly enlarged input current. Meanwhile, the range of automatic transimpedance adjustment is enhanced utilizing the automatic gain control (AGC) circuit, tunable pre-amplifier (PrA), and variable gain amplifier (VGA). Besides the above blocks, the TIA with a size of 1.26 × 1.33 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> also integrates level shifter, post-amplifier, buffer, DC offset cancellation (DCOC), bandgap reference (BGR), and low-dropout regulator (LDO). With a single 3.3-V external supply voltage, the fully integrated TIA in 0.11 μm CMOS achieves a measured input dynamic range up to 7.4 mA@2.5 Gb/s, an input referred noise as low as 137.3 nA and a differential trans-impedance gain of 10 kQ. Taking the bandwidth, dynamic range, and trans-impedance gain into account, the fabricated CMOS TIA demonstrates the largest input dynamic range with maintaining competitive comprehensive performance.

1,4-Dioxane-contaminated groundwater remediation in the anode chamber of a microbial fuel cell.

A two-chambered microbial fuel cell (MFC) was used for the first time for the remediation of an emerging contaminant-1,4-dioxane in its anode chamber. Groundwater historically detected 1,4-dioxane contamination was sampled from a Superfund site. Comparative study was carried out between metabolic (i.e., 1,4-dioxane as sole carbon source) and cometabolic (i.e., 1,4-dioxane and methanol as carbon sources) anodic degradations. It was found that cometabolic degradation increased 1,4-dioxane removal by 10%-52% after 7days and increased maximum power production of the MFC by 18% to 88.9mW/m3 . Oxalic acid was detected as a main metabolic degradation product. Beside oxalic acid, acetic acid and isopropanol were also detected as main products for cometabolic degradation. The presence of a biofilm for 1,4-dioxane anodic degradation was observed by a scanning electron microscopy. Phyla of Bacteroidetes, Firmicutes, and Proteobacteria, as well as a variety of species, were identified for the first time-especially Rikenella sp. and Solitalea canadensis, whose relative abundances were the highest of 18.8% and 24.0% for metabolic and cometabolic degradation, respectively. This study provided an innovative and sustainable approach for 1,4-dioxane anodic biodegradation, which would be potentially utilized for remediation of groundwater contaminated by 1,4-dioxane. PRACTITIONER POINTS: Groundwater contaminated with 1,4-dioxane was remediated in the anode chamber of a two-chambered microbial fuel cell. Cometabolic pathway increased 1,4-dioxane removal and power production of the MFC compared to metabolic pathway. The presence of a biofilm for 1,4-dioxane anodic degradation was observed, and oxalic acid was a main degradation product. This study would be potentially utilized for 1,4-dioxane-contaminated groundwater remediation with simultaneous energy production. External voltage supply for bioelectrochemical remediation of groundwater would potentially be reduced when treating chlorinated hydrocarbons co-occurred with 1,4-dioxane.

The Effect of Intelligent Semi-Active Thermal Exchange- Fuzzy Inference System in Structural Seismic Rehabilitation

The effect of intelligent semi-active thermal exchange-fuzzy controller in structural rehabilitation by attenuating seismic responses of structural systems is investigated. In the suggested structural controller, MR dampers and their sensors are employed as a semi-active controller. Resultant control forces of MR damper are administrated by providing external voltage supply during the earthquakes and high intensity winds. Moreover, a novel evolutionary algorithm of thermal exchange (TE) is applied to compute the optimal location and the quantity of Magnetorheological (MR) dampers and their sensors with regard to minimizing resultant vibration magnitude. An optimal semi-active Thermal Exchange-Fuzzy Controller (TE-FC) has been suggested to administrate MR damper ingeniously. Results of numerical simulations illustrate the efficiency of suggested control system. The TE-FC can determine the optimal control arrangement and forces during a reasonable number of iterations. In comparison of the performance of various control strategies, the TE-FC demonstrates that economical cost and rehabilitation properties of the building could be optimized simultaneously. The TE-FC managed the optimal control forces online during strong ground motion, to attenuate the excessive responses in several rehabilitated buildings. Consequently, the TE-FC could improve the reliability of rehabilitated structure in comparison with passive and offline controllers. The significant efficiency of optimal arrangement of dampers and sensors over uniformly distribution of damper and sensors is presented as well.

Design of the RRAM-Based Polymorphic Look-Up Table Scheme

The polymorphic gates are the circuit cells that deliver different functions with the different external input, supply voltage or temperature. It is an effective method to resist the reverse engineering attacks, for the attackers cannot distinguish the correct function based on the netlist of the circuit. The researchers have found out that the RRAM based Look-Up Table (LUT) has higher performance and less area, comparing with the CMOS based counterparts. However, the attackers can tell the functions of the previous proposed RRAM based LUTs by measuring the resistance states of the RRAM cells. This work proposes an RRAM based polymorphic gate, which implements 16 basic logic functions with 8 RRAM cells in 4 working cycles. Furthermore, the multi-input LUT scheme is proposed based on the polymorphic gate. It is difficult for the attackers to distinguish the circuit function, because the function of the LUT is determined by the applied voltages and the resistance states of the RRAM devices, and the n-input LUT circuit is implemented with the constant area regardless of the number of inputs.

Three‐stage GaN‐on‐SiC medium‐power LNA exploiting a current‐reuse architecture

A recently presented implementation of the current-reuse concept, specifically devised for microwave cascaded single-ended amplifiers, is applied to the design of a three-stage medium-power low-noise amplifier (LNA) operating in X-band. The LNA is realized on a GaN-on-SiC 0.25 µm technology supplied by Leonardo S.p.A.'s internal foundry and achieves a transducer gain (GT) of 24 dB, a noise figure (NF) better than 2.5 dB and an output power at 1 dB gain compression (Pout,1dB) higher than 20 dBm over the whole X-band. The first two stages of the LNA are stacked and share the same current while requiring, as a pair, a doubled external supply voltage, which corresponds to that of the third, medium-power stage. The versatility of the adopted current-reuse concept is exemplified by the fact that the two low-noise stages are initially designed in a conventional single-ended topology: only in a second step are they converted into a current-sharing stage pair with no significant effect on RF performance. Nonconventional approaches to low-noise design and small-signal stability analysis developed by the Authors and adopted in this design are referred to the Reader.

Design of an electrostatic phase shifting device for biological transmission electron microscopy

I suggest an electrostatic phase plate designed to broaden the contrast transfer function of a transmission electron microscope operated close to Scherzer defocus primarily in the low resolution direction. At higher defocus the low frequency behavior is equal to that close to Scherzer defocus, but CTF-correction becomes necessary to extend image interpretation to higher resolution. One simple realization of the phase plate consists of two ring shaped electrodes symmetrically surrounding the central beam. Since no physical components come into contact with the central beam and charge on the electrodes is controlled by an external voltage supply, problems with uncontrolled charging are expected to be reduced.

Coupling coefficient reconfigurable quadrature coupler based on mechanical switches

The conventional reconfigurable quadrature coupler configuration usually requires an external supply voltage which reduces its robustness. A new quadrature coupler with reconfigurable coupling coefficient is implemented using a mechanical control approach to simultaneously satisfy high performance and reliability requirements. Two mechanical switches are firstly implemented on a circular patch to realize two states with different coupling coefficient. To further increase the flexibility in reconfigurability, two more mechanical switches are employed. For demonstration purposes, two patch quadrature couplers were designed, simulated, and measured. The coupling coefficient of coupler I can be switched between 9 dB and 3 dB from 4.9 GHz to 5.3 GHz. Coupler II gave a reconfigurable coupling coefficient, which can be switched between 4 dB, 6 dB, and 11 dB at 3.5 GHz.

A fuzzy logic controller for optimal structural control using MR dampers and particle swarm optimization

Control devices can be used to dissipate the energy and attenuate undesirable vibration on engineering structures. Recently, to mitigate the response of structures during the earthquakes and high intensity winds, semi active control has been widely used. MR dampers are semi active control devices that are managed by sending external voltage supply. A new adaptive fuzzy logic controller (FLC) is introduced to manage MR damper intelligently. Furthermore, a novel evolutionary algorithm of particle swarm optimization (PSO) was used to optimize the placement and the number of MR dampers and sensors in the sense of minimum resultant vibration magnitude. Numerical efforts were considered to validate the efficiency of proposed FLC. In designer’s point of view, the proposed PSO-FLC controller can find the optimal solutions during a reasonable number of iterations. Finally, results demonstrate that proposed PSO-FLC controller could find the appropriate control force and attenuates the excessive responses in several buildings.

A High Efficiency Self-Powered Rectifier for Piezoelectric Energy Harvesting Systems

A high efficiency self-powered rectifier for piezoelectric (PE) energy harvesting systems is proposed. The rectifier in this paper increases the harvested power from the PE transducer by using two switches to reset the transducer capacitor when appropriate. The control circuit for the proposed rectifier is simple and does not require an external supply voltage. Furthermore, the passive diode of the conventional full-bridge (FB) rectifier is replaced by active diode to reduce the voltage drop along the conduction path and thereby increases the power extraction and conversion capability. Based on SMIC 0.18[Formula: see text][Formula: see text]m standard CMOS technology, the simulation results show the voltage conversion efficiency can reach up to 98.9% and the maximum power efficiency is 93.1% when the input current source [Formula: see text]A in parallel with internal capacitor [Formula: see text][Formula: see text]nF and internal resistor [Formula: see text][Formula: see text]M[Formula: see text].