Electric Current Generation Research Articles

Vapor bubble induced electric current generation

Abstract Contact electrification (CE) has been utilized in various energy conversion systems in recent years. This work presents a constant electric energy output that was generated based on the CE at the water–metal interface. When a grounded Pt mesh is placed in water that is heated to boil, a continuous flow of electrons between the Pt mesh and the ground is generated. A possible mechanism for the generation of such electric current is based on the CE between the surface of the Pt mesh and water molecules. The local high-pressure thin liquid film regions between vapor bubbles and surface of Pt mesh promote this CE process. The constant water evaporation and bubble detachment enable the continuous electric current output. In this work, the impact of the heating temperature and the bias voltages on the generation of the current was also studied. This work provides an alternative approach to generate unidirectional current on the basis of CE at the water–metal interface, and it also offers new insights in the design of CE-based systems for the generation of electricity.

Three-phase alternating current liquid metal vortex magnetohydrodynamic generator

SummaryMagnetohydrodynamic (MHD) generators directly convert mechanical energy to electrical energy. However, due to production of low amplitude voltages at low fluid velocities, they are not useful for electronic devices requiring power at watt scale. This work introduces vortex MHD, capable of producing voltages on scale of volts and generating power on a scale of watts. This is achieved by using Galinstan, a highly conductive metallic fluid, which remains liquid at room temperature. The proposed device comprises an impeller and set of copper coils positioned in a ferromagnetic housing. Three-phase AC current is passed in the coils producing a rotating magnetic field. The interaction of a moving conductive fluid and rotating magnetic field governed by Faraday's law of induction serves as a mechanism of electrical current generation. The study investigates the system performance and, in particular, variation of power with respect to system parameters like fluid inlet velocity and stator current.

Molecular mechanisms regulating the catabolic and electrochemical activities of Shewanella oneidensis MR-1.

Electrochemically active bacteria (EAB) interact electrochemically with electrodes via extracellular electron transfer (EET) pathways. These bacteria have attracted significant attention due to their utility in environmental-friendly bioelectrochemical systems (BESs), including microbial fuel cells and electrofermentation systems. The electrochemical activity of EAB is dependent on their carbon catabolism and respiration; thus, understanding how these processes are regulated will provide insights into the development of a more efficient BES. The process of biofilm formation by EAB on BES electrodes is also important for electric current generation because it facilitates physical and electrochemical interactions between EAB cells and electrodes. This article summarizes the current knowledge on EET-related metabolic and cellular functions of a model EAB, Shewanella oneidensis MR-1, focusing specifically on regulatory systems for carbon catabolism, EET pathways, and biofilm formation. Based on recent developments, the author also discusses potential uses of engineered S. oneidensis strains for various biotechnological applications.

Processing Quantum Signals Carried by Electrical Currents

Recent developments in the coherent manipulation of electrons in ballistic conductors include the generation of time-periodic electrical currents involving one to few electronic excitations per period. However, using individual electrons as carrier of quantum information for flying qubit computation or quantum metrology applications calls for a general method to unravel the single-particle excitations embedded in a quantum electrical current and how quantum information is encoded within it. Here, we propose a general signal processing algorithm to extract the elementary single-particle states, called electronic atoms of signal, present in any periodic quantum electrical current. These excitations and their mutual quantum coherence describe the excess single-electron coherence in the same way musical notes and score describe a sound signal emitted by a music instrument. This method, which is the first step towards the development of signal processing of quantum electrical currents is illustrated by assessing the quality of experimentally relevant single electron sources. The example of randomized quantum electrical currents obtained by regularly clocked but randomly injected unit charge Lorentzian voltage pulses enables us to discuss how interplay of the coherence of the applied voltage and of the Pauli principle alter the quantum coherence between the emitted single particle excitations.

Cyclic voltammetry studies of bioanode microbial fuel fells from batch culture of Geobacter sulfurreducens

The present study aims to investigate the performance of batch culture of Geobacter sulfurreducens (G. sulfurreducens) for electrical current generation via cyclic voltammetry (CV) method. The CV study was performed with an applied voltage in the range of -0.1 to 0.1 V against the standard calomel electrode (SCE) during the cell growth and attachment of G. sulfurreducens on graphite felt and initial acetate concentration of 20 mM. The kinetics of electrode reaction was investigated by conducting CV experiments at different scanning rates of 5, 10, 20, 50 and 100 mVs -1. The diffusion coefficients (D) and heterogeneous electron transfer rate constant (k o) of both anodic and cathodic process were 1.04×10 -5 cm 2·s -1, 1.73×10 -6 cm 2.s -1, 0.0004 cm.s -1 and 0.0011 cm.s -1, respectively. The obtained results showed that the anode exhibits high bioeletrocatalytic activity due to the attachment of G. sulfurreducens on the anode surface.

Impact of electron scavenging during electric current generation from propionate by a Geobacter co-culture

Propionate accumulates and inhibits anaerobic biodegradation processes. Technologies such as bioelectrochemical systems (BES) are being developed to remove this volatile fatty acid and convert it into bioenergy. Geobacter metallireducens is an electrogenic bacterium capable of oxidizing propionate, but slowly and inefficiently. Here, G. metallireducens was submitted to adaptive laboratory evolution (ALE) to improve its propionate metabolism. The adapted G. metallireducens, which harbors 62 mutations, reduced Fe(III) 3.6 times faster than the wild type with propionate as substrate. During growth, the adapted strain generated H2 at a rate of 25.4 μM h−1. To determine if quick H2 removal could accelerate propionate oxidation further, the adapted G. metallireducens was co-cultivated with a H2-oxidizing autotrophic Geobacter sulfurreducens strain. With Fe(III) as the electron acceptor, the co-culture oxidized propionate 2.2 times faster than the adapted G. metallireducens pure culture. In a BES, the co-culture outperformed the pure culture and generated a maximal current density of 2.34 A m−2. The anode of the co-culture-driven BES was coated by a thick biofilm reaching 116 μM made of both Geobacter species uniformly distributed. These results demonstrate that the combination of ALE and co-cultivating is an efficient strategy to optimize the metabolism of G. metallireducens for propionate-driven bioprocesses.

Colour Me Blue: The History and the Biotechnological Potential of Pyocyanin.

Pyocyanin was the first natural phenazine described. The molecule is synthesized by about 95% of the strains of Pseudomonas aeruginosa. From discovery up to now, pyocyanin has been characterised by a very rich and avant-garde history, which includes its use in antimicrobial therapy, even before the discovery of penicillin opened the era of antibiotic therapy, as well as its use in electric current generation. Exhibiting an exuberant blue colour and being easy to obtain, this pigment is the subject of the present review, aiming to narrate its history as well as to unveil its mechanisms and suggest new horizons for applications in different areas of engineering, biology and biotechnology.

Synthesis of glycogen by Chlorobium limicola IMV K-8 while growth in wastewater

Due to the high content of organic compounds, the distillery wastewater can be a good substrate for the production of glycogen during cultivation of green photosynthetic bacteria. Green photosynthetic bacteria Chlorobium limicola IMV K-8 are producers of glycogen and show exoelectrogenic properties when grown alone or inside the co-culture with heterotrophic bacteria-exoelectrogens in wastewater of various origins. In our previous works it was found that due to the phototrophic growth of C. limicola IMV K-8 in the distillery wastewater significantly reduces the content of compounds of nitrogen, sulfur, Ca2+, Mg2+ and others. The study of the patterns of glycogen synthesis by green photosynthetic bacteria during growth in such an extreme environment as the wastewater of a distillery has prospects for the development of biotechnology for the production of this polysaccharide. The aim of the study was to investigate the glycogen content in C. limicola IMV K-8 cells under different growth conditions in the wastewater of the distillery. Bacteria were grown in the wastewater of the distillery under light (phototrophic growth) and without light exposure (heterotrophic growth). Bacterial cells grown on GSB medium under light (phototrophic growth) and without light (heterotrophic growth) exposure were used as controls. Glycogen content was determined at 7, 14, 21 and 30 days of growth by the glucose oxidase method. Glucose or glycogen in the wastewater of the distillery without the introduction of bacteria was not detected. It was found that the content of glycogen in cells of C. limicola IMV K-8 grown in the wastewater of the distillery, under light exposure increased from 3.8 % to 39.8 % of cells dry weight from the seventh to third day of growth during 30 days of cultivation and was 2 times higher the glycogen content of cells on GSB medium. It is assumed that the bacteria C. limicola IMV K-8 use available in the water sources of carbon and other compounds necessary for cell metabolism along with glycogen biosynthesis and bioremediation of wastewater. During C. limicola IMV K-8 growth in the darkness there is an assimilation of organic sources of carbon (acetate, pyruvate and probably organic compounds of wastewater), which allows cells to remain viable for 30 days without additional sources of carbon, nitrogen, etc., but significant glycogen synthesis does not occur. The glycogen formed under phototrophic conditions can be further a source of carbon or a substrate for electric current generation by exoelectrogenic bacteria.

Generation of magnetic field in the low-latitude ionosphere by tsunami wave

The travel of a tsunami wave is accompanied by generation of geomagnetic field perturbation and acoustic-gravity wave (AGW) propagating into the ionosphere. We consider a mechanism of electric current generation by the tsunami wave in the ocean and ionosphere. The electric current in the ocean is generated by motion of conducting seawater in geomagnetic field, and in the conducting ionosphere it is generated by AGW propagation from the atmosphere. The electric current in the ionosphere may be greater than in the seawater due to exponential increase of amplitude of the upward-propagating AGW. The equations of magnetic field in the “ocean-atmosphere-ionosphere” model in the inclined magnetic field were derived. The spatial distribution of the magnetic field perturbation in the atmosphere and ionosphere was calculated. It is shown that the electric current in the ionosphere significantly changes the geomagnetic field perturbation. An influence of the geomagnetic field inclination on its perturbation is analyzed. Our results demonstrate a possibility of satellite monitoring of tsunami wave based on recording electromagnetic field in the middle and low latitudes.

A Living Biotic–Abiotic Composite that can Switch Function Between Current Generation and Electrochemical Energy Storage

AbstractPower generation and charge storage devices are commonly uncoupled when it comes to the design of materials relevant for their fabrication. Here, it is demonstrated that the biotic–abiotic composite comprising the self‐doped conjugated polyelectrolyte CPE‐K and electrogenic bacteria Shewanella oneidensis MR‐1 can reversibly switch its function between electrical current generation in chronoamperometry mode (≈150 mA m−2) and electrochemical energy storage as a pseudocapacitor with a specific capacitance of up to 80 F g−1. Interconversion of desirable properties for the different functions is achieved by the simple addition and removal of Mg2+ in the bulk electrolyte. Potentiostatic, galvanostatic, and electrochemical impedance spectroscopy characterization, accompanied by imaging and cell viability tests, indicate that the modulation of properties is a result of reversible changes in CPE‐K macrostructures and in the number of living bacteria within the composite. The results show the possibility to realize an “on‐demand” switch between current generation and charge storage by one integrated “living” material.

Ammonium sulfate production from wastewater and low-grade sulfuric acid using bipolar- and cation-exchange membranes

Conventional electrodialysis can be used to recover ammonia from dewatering centrate (i.e., down-stream wastewater from digested sludge dewatering). However, ionic impurities of the recovered ammonia solution are still a limiting factor for broad applications of ion-exchange membranes (IEMs) in wastewater treatment and resource recovery. In this study, an electrodialysis stack with bipolar membranes (BPMs) and cation exchange membranes (CEMs) but without anion exchange membranes (AEMs) was examined under various operation conditions to demonstrate high-purity ammonium sulfate production using low-grade sulfuric acid and dewatering centrate. Two significant benefits of removing AEMs from the bipolar membrane electrodialysis (BMED) are no more membrane fouling problems on AEMs and complete exclusion of impurity anions (e.g., chloride ions) in the recovered ammonium sulfate solution. A higher applied voltage condition (30 V over 7 pairs of CEM and BPM) resulted in a substantially high ammonia recovery (88.4%) and concentration (4.34 g-N/L) in 90 min. The ammonia recovery and concentration were also improved by increasing the flow rate through the BMED stack. The lowest electric energy consumption in the membrane stack was 9.6 kW h/kg-N, indicating energy efficient production of high-purity ammonium sulfate from wastewater. The amount of divalent cation scales accumulated in the BMED stack was linearly proportional to the average electric current, implying that the scaling problem can be controlled by reducing the applied voltage. Even with the scale accumulation, the electric current generation (i.e., separation performance) was hardly affected during the experiment. These findings demonstrated the strong potential of AEM-lacking BMED for practical ammonia separation from wastewater with reduced impurities.

Альтернативный источник энергии для автономных потребителей на основе низкотемпературного двигателя Стирлинга

Introduction. The relevance lies in the use of a motor with an external heat supply to convert solar radiation into electrical energy, while the source of thermal energy is a solar collector. Aim. To develop an alternative energy source for remote consumers based on a low-temperature Stirling engine capable of converting low-grade heat of heated water into mechanical energy with subsequent generation of electric current of industrial frequency. In contrast to the classical design of the well-known Stirling engine, the presented DVPT has a significant displacer volume, which exceeds the volume of the working piston by more than 20 times; this allows it to operate at a lower temperature difference between the heater and the cooler. The operating temperature of the heater is 90–100 °C, which is 7–9 times less than the known Stirling engine. Materials and methods. To work out the results of full-scale experiments, computer modeling was used; the dependence graphs for the change in the pressure of the working fluid and its volume when compressed by the working piston are presented. Results. A brief description of the design features of a low-temperature engine with an external heat supply operating according to the Stirling cycle is given, as well as some results of research and computer modeling. Conclusion. The use of air as a working fluid is not justified, since when using it, the mass and size dimensions of the DVPT per unit of power produced are larger than that of internal combustion engines. For a low-temperature DVPT, a prerequisite is the difference in the volumes of the displacer and the working piston; for a heater temperature within 90 °C, the displacer must be 20 to 40 times larger in volume. The efficiency is influenced by the temperature difference between the heater and the cooler and the pressure of the working fluid.

Multi-physics simulation of transport phenomena in planar proton-conducting solid oxide fuel cell

A thermo-fluid reacting numerical model for the multiphysics process in the planar proton-conducting solid oxide fuel cell (SOFC) is presented. A non-dimensional formulation of the governing equations is derived aimed to specify the dimensionless quantities that influence the power generation in SOFC, those being the Sherwood, Peclet, Reynolds, Darcy, Butler–Volmer, the first Damkohler, and the third Damkohler numbers. The model is implemented in an in-house computational code and shown to be in adequate agreement with experimental data from the literature to verify the efficacy of the model. A parametric study is subsequently conducted to understand the effect of porous electrodes parameters on the performance of SOFC. It is found that decreasing the Darcy and increasing Sherwood and Reynolds numbers results in a depletion of gas species in the electrochemically active area of the cell and thus a reduction in the electrical current generation. In addition, a high Peclet and the third Damkoler numbers increase SOFC operating temperature, leading to an improvement in the cell power density.

Influence of the Shape and Size of Ag Nanoparticles on the Performance Enhancement of CIGS Solar Cells: the Role of Surface Plasmons

The efficiency of thin-film solar cells can be increased considerably by coupling the solar cells with plasmonic nanoparticles. However, while the benefits of utilizing plasmonic nanoparticles has formerly been recognized, the physical properties of the nanoparticles at which the conversion efficiency is optimized have not yet been completely studied. Among the possible properties, this study investigates meticulously the effects of plasmonic nanoparticle shapes and size on the improvement of the energy conversion efficiency of CIGS solar cells. Two different shapes including spheres and cylinders were analyzed in this study. It was revealed that the cylindrical Ag nanoparticles with a diameter of 50 nm and a height of 125 nm placed in an array with period of 215 nm exhibited the most substantial enhancement in the optical absorption and electrical current generation. The achievements in this article have been attained through optical and electrical analysis as well as the near-field imaging studies.

The Inverse Relationship between Metal-Enhanced Fluorescence and Fluorophore-Induced Plasmonic Current

In this work we investigate the relationship between metal-enhanced fluorescence (MEF) and fluorophore-induced plasmonic current (PC). This is accomplished through measurements of both radiative emission (MEF) and direct electrical current generation between discrete metal nanoparticles upon fluorophore excitation (PC). We have conducted these measurements on silver and gold nanoparticle island films, over a range of nanoparticle sizes and spacing in the films. We have observed an inverse relationship in the magnitude of MEF with PC, where larger and more closely spaced metal nanoparticles are found to result in increased PC and subsequently a decreased MEF. We attribute this effect to the relatively high capacitance and low charging energy of large and closely spaced particles, providing an outlet for plasmon relaxation in the form of electron flow and electrical current generation. These results are significant as they open potential for controlling for and the optimization of both MEF and PC.

Seismoelectric effect in Lamb’s problem

Seismoelectric effect is studied in the framework of classical Lamb’s problem with impulse or time- variable mechanical action on an elastic porous half-space. Radiation of elastic waves gives rise to pressure variation of groundwater fluid contained in pores and cracks. This causes the generation of telluric electric fields and currents due to the seismoelectric effect. A diffusion type equation is applied to describe the variations of the pore pressure and telluric electric field. Particular emphasis has been placed on the properties of seismoelectric signals caused by Rayleigh wave propagation since this wave has maximal amplitude at a considerable distance from the seismic source. For practical purposes and geophysical application, the co-seismic phenomena related to seismoelectric effect are examined in more detail.

Electrical current generation from a continuous flow macrophyte biocathode sediment microbial fuel cell (mSMFC) during the degradation of pollutants in urban river sediment.

A new type of sediment microbial fuel cell (SMFC) with floating macrophyte Limnobium laevigatum, Pistia stratiotes, or Lemna minor L. biocathode was constructed and assessed in three phases at different hydraulic retention time (HRT) for electrical current generation during the degradation of urban river sediment. The results showed a highest voltage output of 0.88 ± 0.1V, maximum power density of 80.22mWm-3, highest columbic efficiency of 15.3%, normalized energy recovery of 0.030kWhm-3, and normalized energy production of 0.005kWhm-3 in the Lemna minor L. SMFC during phase 3 at HRT of 48h, respectively. Highest removal efficiencies of total chemical oxygen demand of 80%, nitrite of 99%, ammonia of 93%, and phosphorus of 94% were achieved in Lemna minor L. system, and 99% of nitrate removal and 99% of sulfate removal were achieved in Pistia stratiotes and Limnobium laevigatum system during the SMFC operation, respectively. Pistia stratiotes exhibited the highest growth in terms of biomass and tap root system of 29.35g and 12.2cm to produce the maximum dissolved oxygen of 16.85 ± 0.2mgL-1 compared with other macrophytes. The predominant bacterial phylum Proteobacteria of 62.86% and genus Exiguobacterium of 17.48% were identified in Limnobium laevigatum system, while the class Gammaproteobacteria of 28.77% was observed in the control SMFC. The integration of technologies with the continuous flow operation shows promising prospect in the remediation of polluted urban river sediments along with the generation of electrical current.

Wind Energy toward Electric Current Generation in Borno State, Nigeria

This research focused on evaluating the prospect of wind energy for electric power generation in Borno State, Nigeria was carried out. Sixteen years of monthly mean wind data at 10 m height of anemometer from the ministry of aviation Maiduguri (Maiduguri meteorological center) Nigeria were assessed and snubbed to Weibull two parameter and Rayleigh model of probability distribution. It was found that its monthly and annual variation recorded for the maximum speed were 6.97 m/s in 1997 and 5.23 m/s in 2001 respectively and the minimum wind speed was 1.00m/s and occur in the year 2012. The maximum mean wind speed occurs in March, June, July and August while the minimum value occurs in September. Maiduguri is a potential wind farm area; the moderate wind falls within the consistent values for wind power generation to operate wind turbine for electric power conversion. The study also displays that Maiduguri has annual power density approximately to power class (2) which is 87.98 W/m2 showing that it is perfect for grid connection and application.

EXPERIMENTAL RESEARCHES OF JUMP-SHAPED CHANGES OF CURRENT AND VOLTAGE IN TRANSIENT SWITCHING CIRCUITS OF AC GENERATION

The article considers the transient process in switching electrical circuits, which are available in electric current generators in the form of a surge of supercurrents and voltage when removing, from isolated plates, brushes and which are lost in unused form. These bursts in collected form account for about-30-35% of the energy generated by the generator. The work is devoted to analysis of the available theoretical works on transients and experimental study of current surges and voltage in switching circuits, similar in electric motors and elk-regenerators. The results are given of the experimental study in the switching circuits of the electric generator in the work.

Electric current generation of a droplet falling into an electrolyte solution

A novel system which can greatly improve the waving potential [1] of metal produced by a moving liquid–solid boundary is presented in this paper. By using a pair of copper electrodes immersed in an electrolyte solution, a significant electric potential is generated by changing the wetted surface area of only one electrode when a droplet falls into the electrolyte solution. Experiments show that the electric potential difference between the two electrodes is generated due to different wetted areas at the two electrodes. The magnitude of the generated electric current depends on the types of the electrolyte solution and the moving speed of the air-electrolyte solution interface. A droplet of 24 µL can generate a waving potential of three orders of high than that reported in the reference paper [1]. The approach of inserting a pair of asymmetrically insulated metal electrodes into an electrolyte solution makes it possible to utilize ordinary pure metal materials for harvesting waving potential energy from a dynamic moving liquid–air interface.