Electromotive Force Values Research Articles

CREATION OF A CHEMICAL CURRENT SOURCE USING REDOX REACTIONS IN THE "IODINE-IODIDE" SYSTEM

Chemical current sources play an important role in energy supply systems that are closely related to everyday life. The ever-increasing dependence on electricity creates a huge demand for appropriate energy storage devices. The purpose: The aim of the work is to create a chemical current source based on the use of the "red – ox" iodine-iodide system and to determine the patterns of formation of electromotive force (EMF) and short-circuit current (short-circuit current) in water solutions depending on the concentration of ions. Objects. The experiments are carried out by measuring the EMF formed between graphite electrodes and SCC. A special installation has been assembled, consisting of an electrolyzer with separated electrode spaces, an ammeter, a voltmeter and graphite electrodes. Solutions of iodine and potassium iodide served as the electrolyte. Results. In an electrolyzer, the electrode spaces of which are separated by an anionite membrane, when one of the spaces is filled with a solution of iodine and the other with potassium iodide, an EMF is formed between the graphite electrodes. Under optimal conditions, the EMF and SCC values will be higher than 135 mV and 10 mA, respectively. Conclusion. The possibility of forming a chemical current source using the "red – ox" iodine-iodide system is shown. The patterns of EMF and SCC formation and their changes depending on ion concentrations are revealed. The results of the study show that "red – ox" systems of alternating valent elements can be used to create flowing chemical current sources with increased electrical capacity.

Investigation of the process of formation of a chemical current source in the «red-ox» Fe(II) – Fe(III) system in a sulfuric acid environment

Among the technologies designed to save energy, flow-through batteries deserve special attention. Their principle of operation is based on the use of systems of variably valent ions. The aim of the work is to create a chemical current source based on the use of the "red – ox" Fe(II)/Fe(III) system and to determine the patterns of formation of electromotive force (EMF) and short-circuit current (SCC) in acidic solutions depending on the concentration of ions. The experiments are carried out by measuring the EMF formed between graphite electrodes and SCC. A special installation has been assembled, consisting of an electrolyzer with separated electrode spaces, an ammeter, a voltmeter and graphite electrodes. Acidified solutions of iron (II) and iron (III) sulfates served as the electrolyte. In an electrolyzer, the electrode spaces of which are separated by an anionite membrane, when one space is filled with iron (II) sulfate and the other with iron (III) sulfate, an EMF occurs between graphite electrodes. When making contact between graphite electrodes, iron (II) oxidation occurs in the first electrode space, and iron (III) reduction occurs in the second. A chemical current source is being formed. At a concentration of iron (III) equal to 20 g/l, a change in the concentration of iron (II) in the range of 1-40 g / l contributes to a shift in the potential of the graphite electrode to negative values. At a concentration of Fe(III) equal to 1 g/l, the potential value is 509 mV, and at 40 g / l – 475 mV. At a constant concentration of iron (II), the addition of Fe(III) leads to a shift in the EMF value to the right. It was found that as a result of these changes, an increase in EMF and SCC is observed.

Thermoelectric Micro-Scale Generation by Carbonaceous Devices

The paper reports on research focused on the use of largely available carbonaceous materials, such as graphite, carbon black and chars, as thermoelectric materials for micro-generation at high temperature. The key feature is the possibility to ignite the thermoelectric device to self-sustain electric generation. The results of the tests performed with such materials, under both cold and hot conditions, showed that a significant change of the electromotive force, with absolute increase up to three orders of magnitude, occurred under hot conditions with flame irradiation, achieving measured values of electromotive force up to 55 mV, in the best case. Monoliths based on biomass chars and covered with a layer of gunpowder gave rise to similar variation of the Seebeck coefficient, as the case of the flame exposed samples. This result confirms the basic idea of the investigation and the possibility of generating an electrical peak in a self-sufficient combustion thermoelectric device with power up to 1.0 W. A theoretical assessment has been proposed to provide an interpretation of the observed phenomenology, which is related to the non-linear dependence of the material properties on temperature, in particular the Seebeck coefficient and thermal conductivity.

Power-Dependent Characteristics of Spin Current Transfer in Metal Bilayer Devices under High-Power Pulse Excitation.

The power-dependent transfer characteristics of spin currents generated at the interface of the permalloy/Pt bilayer device have been investigated over a wide power range from a few tens of milliwatt to 396 W. We built a high-power pulse excitation system for spin pumping, which achieves large electromotive force (EMF) values of 10 mV at 396 W excitation through the inverse spin Hall effect (ISHE) and demonstrates that the EMF generation after pulse excitation is very fast. Under strong pulse microwave excitation more than 80 W, the EMF spectrum exhibits an asymmetrical lineshape, which is well reproduced by simulations that take into account the fold-over effect due to the nonlinear ferromagnetic resonance excitation. The maximum output power at an external load through spin pumping and the ISHE is shown to increase in proportion to the square of the input microwave power (Pin) in the power range below 80 W. This power generation proportional to Pin2 is unique to spin current-mediated power flow. In the strong excitation regime with the fold-over type EMF spectra, the EMF values of the peak magnetic field position are found to increase less linearly due to spectral broadening. This feature can be used for power generation that increases nonlinearly with respect to the input excitation power, where the nonlinearity is adjusted by varying the magnetic field position.

On the Issues of Spatial Modeling of Non-Standard Profiles by the Example of Electromagnetic Emission Measurement Data

This paper examines the possibility of the spatial modelling of the Earth’s natural pulsed-electromagnetic-field measured values, which form a closed profile without the data inside. This geophysical method allows us to map active tectonic movement which breaches the integrity of pipes. During the experiment, 4.5 km of profiles were measured in the Admiralteysky district of St. Petersburg, Russia. Regular electromotive force (EMF) values and anomalous EMF values were obtained, ranging from 0 to 900 µV and above 900 µV, respectively. The anomalous values are associated with tectonic faults in the bedrock. The data obtained are characterized by complex spatial anisotropy associated with the development of two groups of tectonic faults of different orientations. The authors have considered the problems of the spatial modeling of the data obtained. The main problems, the solutions to which should allow the obtaining of adequate models, have been identified. Based on the analysis of the measurement results, geological features of the studied areas, as well as variography, the following possible solutions were proposed: changing the measurement technique; dividing the data array according to the main directions of anisotropy; the need to introduce additional correction coefficients. The problem revealed in this article requires further research on the basis of the obtained results, which will reduce the cost and timing of such studies, and, as a result, give an opportunity to take into account active tectonic disturbances during the construction and scheduled maintenance of underground utilities, which is especially important within the framework of the concept of sustainable development.

Analytical model for electromagnetic induction in pulsating ferrofluid pipe flows

Energy harvesting processes using ferrofluidic induction—a process that generates voltage via the pulsation of a ferrofluid (iron-based nanofluid) through a solenoid—have received increasing attention over the past decade. In this paper an analytical model is proposed to predict the induced electromotive force (EMF) based on the flow behavior and magnetic properties of a pulsating ferrofluid energy harvesting device. The ferrofluid is treated as an idealized series of discrete magnetic ‘slugs’ within passing through the solenoid, and the model identifies key parameters for describing and optimizing ferrofluidic induction in pulsating pipe flows. The resulting expression for induced EMF as a function of slug position relative to the solenoid is numerically integrated to determine the root mean square (RMS) of EMF during one pulsation cycle. Data from a previously documented study using an experimental induced EMF test rig is analyzed to find corresponding measured values of EMF RMS and used to validate the analytical model. Experimental and analytical results both show an increase in induced EMF with higher pulse frequency, increased number of bias magnets, and reduced spacing between the magnet and solenoid. At low magnetic flux densities and pumping frequencies, the EMF is negligible; with 0.3 mT magnetic flux density and 9 and 18 Hz pumping frequencies the measured RMS is nominally zero. For a 9 Hz pumping frequency the RMS value of the induced EMF is less than 1 μV at all magnetic flux densities. For the highest pumping frequency examined, 30 Hz, the induced EMF RMS is greater than 1 μV for all magnetic flux densities greater than 0.7 mT. As the experimentally measured values of EMF lie within the uncertainty bounds of the model, induced EMF can be predicted within an order of magnitude for magnetic fluid-induced energy harvesting systems.

ТЕОРЕТИЧЕСКОЕ ОБОСНОВАНИЕ ОЦЕНКИ ТЕХНИЧЕСКОГО СОСТОЯНИЯ ДВИГАТЕЛЯ ВНУТРЕННЕГО СГОРАНИЯ ПО ВЕЛИЧИНЕ СУММАРНОЙ ЭДС В ПАРАХ ТРЕНИЯ

The research was carried out in order to determine the possibility of assessing the technical condition of an internal combustion engine (ICE) by the value of the total electromotive force (EMF) that occurs in its friction pairs. The contact area of the rubbing parts and the gap between them affects the electrical resistance in contact, and, accordingly, the value of the resulting EMF according to the established dependence. To confirm the theoretical results, studies were carried out on the UMP-417 engine using a developed measuring complex and a manufactured current-collecting device mounted on the output end of the engine crankshaft. With the operating mode corresponding to the speed of the crankshaft 800 min-1, the total value of the EMF in the measurement circuit cylinder liner-engine block-crankshaft-current collector (TSU) was 83...95 mV. At the same time, in the piston–cylinder liner friction pair, it was equal to 37 ... 47 mV, and in the crank mechanism friction pairs - 46...48 mV. The correspondence of the results of the theoretical calculation and bench studies of the values of the EMF value for a real internal combustion engine was: when measured using the Fluke device for the friction unit of the cylinder liner-piston – 62.1 %, for the friction units of the crank mechanism (root neck-connecting rod, connecting rod neck-connecting rod, root neck-engine block) - 15.1 %. When measured by the V1net device, for the cylinder liner – piston friction unit-85.5 %, for the crank mechanism friction units (root neck-connecting rod, connecting rod neck-connecting rod, root necks-engine block) - 93.2 %. The proposed method for determining the state of the engine by the value that occurs in its EMF friction nodes can be used in the technical diagnostics of engines

The results of studying the EMF emergence in friction pairs of power machines

The work is devoted to the experimental studies of determining the magnitude of the electromotive force (EMF) that arises in the friction pairs of an internal combustion engine (ICE) and the possibility to assess its technical condition by the magnitude of the electromotive force. A research procedure was designed to carry out an experiment. The measurement of small value voltages was carried out using a control and measuring device, the principle of operation of which is based on operational amplifiers (OA). Based on the previously obtained theoretical values of the EMF, the designed millivoltmeter can make measurements in the range of the following values: from 50 μV to 1 mV and from 1 mV to 40 mV. To ensure the reliability of the readings of the measuring device, its calibration was carried out with the use of an AMPROBE 37XR-A digital multimeter. As a result of the measurements, the relationship between the EMF value and the crankshaft speed of the power plant was established. The analysis of the research results confirms the possibility of diagnostic assessment of the power machine condition by the values of the measured EMF using the proposed measuring complex.

Effect of Thickness and Type of Magnet against EMF Back PMSG 12S8P with FEM

Synchronous Magnet Generator (PMSG) is one of the main components of wind power generation. This generator has excellent low speed applied especially for less strong winds. Electromotive Force (EMF) output is expected to be enhanced for higher PMSG efficiency. This research aims to analyze the influence of thick and magnetic types on EMF Back PMSG 12S8P. Thickness and type of magnets vary to get the highest EMF output. The thickness is variated at a value of 3 mm and 6 mm, while the magnetic material used Neodymium Iron Boron (NdFeB) and PM12 Br 1.2 Mur 1. Linkage flux value is generated with Finite ElemenMethode (FEM) using Magnet 7,5 Software for each variation. From analyze results and compared to other variations, the highest EMF value obtained from the variation in magnetic thickness 6 mm with material type PM12 Br 1.2 Myrrh 1 with EMF value reaching 21.13122 Volt.

Research on novel spatial structure of power generation of spherical robot

Continuous energy supply is essential to spherical mobile robot in the Antarctic investigation. This paper puts forward energy harvesters that can generate electricity from the wind to achieve the long time and the long range exploration. The major contribution is to present the preliminary models of the energy harvester which uses the law of electromagnetic induction, and meanwhile the spatial structures about generating electricity are analyzed, and the influence of different structures on the power generation and efficiency will be obtained. In order to get the characteristics of power generation efficiency, this paper designs one element pipeline model and two element pipeline model, and then the motion of magnet in harvester will be simulated in different installed structures and wind speed. The varying rules of induced voltage are concluded at last. Finally, experiments are implemented based on the simulated model. The experimental results verify the dependability of different structural schemes of the robot and the validity of induced voltages’ varying rules. The results show that the induced electromotive force value obtained by the one element pipeline structure model is larger than the two element pipeline model, but the stability of the latter is better. Through the research in this paper, it can provide a basis for selecting a suitable spherical robot space structure according to the environmental conditions to improve the endurance.

Effect of Hydrogen and Absence of Passive Layer on Corrosive Properties of Aluminum Alloys.

This paper reports the results of research on the effect of hydrogen permeation and the absence of passive layers on the variations in the corrosive properties of aluminum alloys. The study demonstrated that such variations contribute to the deterioration of corrosive properties, which in turn contributes to shortening the reliability time associated with the operation of aluminum alloy structures. The analysis involved structural aluminum alloys: EN AW-1050A, EN AW-5754, and EN AW-6060. It was demonstrated that the absorption of hydrogen by the analyzed alloys led to the shift of the electrode potential to the negative side. The built hydrogen corrosion cells demonstrate in each case the formation of electromotive force (EMF) cells. The initial EMF value of the cell and its duration depends on the duration of hydrogenation. As a result of removing the passive layers, the electrode potential also changes to the negative side. Following the removal of the passive layer from one of the electrodes, the cells also generated a galvanic (metal) cell. The duration of such a cell is equivalent to the time of restoration of the passive layer. The formation of such hydrogen and metal galvanic cells changes the electrochemical properties of aluminum alloys, therefore deteriorates the corrosive properties of aluminum alloys.

Simulation of the pulsating current traction motor

Design and improvement of traction electric engines ensuring reduction of the railway transportation power consumption is a current long-term objective. The objective is to develop technical requirements to the new electric engines, including implementation of the set haulage performance of locomotive, providing for constant power in the certain range of the running speed, as well as required properties in case of the supply network parameters change, selection of the weight and dimensions parameters ensuring fitting of the traction electric engines in the locomotive underframe, and other important tasks. The new technology is proposed for forecasting the engine properties using simulation modeling of the hauling features and electrical characteristics of engine in order to resolve the above mentioned objectives. The proposed pulsating current traction motor model takes into account the eddy currents effect on the processes of magnetic flux changes in the engine steel and the nature of electromagnetic processes in the engine. Electric component of the engine simulation model is added with the torque mechanical balance equation that allows assessing its operating properties to the full extent. Results of calculations are presented in the form of the engine electromotive force attenuation curve calculated for specific mode of operation at the armature current of 780 A and the initial value of electromotive force amounting to 525 V. Obtained parameter of attenuation correlates with the experimental data presented in the other information source. Value of determination factor between the specified curves certifies adequacy of the developed simulation model. Proposed model of engine and methodology of its design allows modeling its operation in transition and in static modes of operation. Engine properties obtained by means of the proposed simulation model n = f(iа) and M = f(iа) are almost similar to the properties of traction engine NB-514 in the entire range of the armature current change iа. Proposed simulation model allows designing pulsating current traction motor with the set operating properties, as well as studying the engine parameters effect on its energy indicators.

BiOCl-based photocathode for photocatalytic fuel cell

A photocatalytic fuel cell with BiOCl as the photocathode and furfural as direct fuel was developed for the first time. We synthesized a uniformly and densely distributed stable BiOCl film on F-doped Tin dioxide in-situ successfully, and X-ray photoelectron spectroscopy results showed the existence of oxygen vacancies on the surface of BiOCl. In the furfural fuel cell, the BiOCl-coated FTO was chosen as the electrode for light-induced oxygen reduction reaction. Linear sweep voltammograms test of the Pt-BiOCl furfural fuel cell showed a higher open circuit voltage than the Pt-Pt furfural fuel cell, which was consistent with the theoretical analysis of a larger electromotive force value under illumination. Gas chromatography-mass spectrometry results showed an obvious degradation effect towards furfural, 5-methyl furfural and 2-acetylfuran, which demonstrated a distinctive way of utilizing non-noble metal as the electrode in photocatalytic fuel cell.

Optimization of Photoelectric Converter Based on a Two-Chamber Na–Ar Gas Photoplasma

An optimization for the design of a two-chamber photoplasma has been carried out to investigate some parameters affecting the conversion of light radiation to electrical energy. For these purposes, 2-D simulation with Plasma Module in COMSOL for a cylindrical two-chamber cell at sodium pressure 0.02 torr and different pressures of buffer gas are carried out. A theoretical model considering plasma chemistry and resonance radiation transfer developed in our previous work was used. The effect of the second chamber dimensions ${L}_{2}=({1-4}) \times 1 {0}^{-2}\,\,{\text {m}}$ and ${R}_{2}=({0.5-3}) \times 1 {0}^{-2}\,\,{\text {m}} $ at a fixed size of the first chamber ( ${L}_{1}={2{R}}_{1}={1}{0}^{-2}\,\,\text {m}$ ), the buffer gas pressure ${P}_{{\text {Ar}}}=({0.1-10 })\,\,{\text {Torr}}$ , and nonhomogeneous spatial distribution of photoexcitation rate have been investigated. It has been established that an optimal value of electromotive force (EMF) 1.037 V takes place at ${P}_{{\text {Ar}}}={5\,\,\text {torr}}$ and ${L}_{2}={R}_{2}={2\times 1}{0}^{-2}\,\,{\text {m}}$ . Also, for the same conditions, calculations of the $I-V$ and $P-V$ characteristics for the photoplasma device are presented. It was established that maximal output power ${P}_{{\text {max}}}={8\times 1}{0}^{-3}\,\,{\text {mW}}$ for these conditions. The obtained results give a good potential for designing a solar photoelectric converter.

The augmented reality application for simulating electromotive force concept

The discussion of the concept of electromotive force often leads to misconceptions. Unity program can produce 3-dimensional media from 2-dimensional media. In this article, we will describe the form of electromotive force simulation that is displayed with augmented reality technology. Development of electromotive force simulation using 4D development model (define, design, develop, and disseminate). The application of augmented reality technology can visualize the three-dimensional form of abstract electromotive force processes into reality. The design process is based on pedagogical content knowledge. The electromotive force display can simulate the impact of changes in the number of turns, magnetic fields, and time of playback of the generator against the value of electromotive force. The simulation has succeeded in providing an interesting description of the ratio of variables to the magnitude of the force of electricity produced in the generator. Display simulation electromotive force with augmented reality technology has met the principle of technological pedagogical content knowledge (TPACK).

Thermoelectric properties of Zn2GeO4 nano-crystals grown on ITO and Au coated Si substrates by thermal evaporation

We have reported the comparison of thermoelectric properties of Zn2GeO4 samples grown on ITO and Au coated Si substrates. Mixed powder of Zn and Ge with 1:1 ratio was evaporated in the tube furnace on ITO and Si substrates using identical experimental conditions. After growth, as grown samples were annealed at different temperatures in oxygen environment. Seebeck and Hall data suggested that the sample grown on Au coated Si substrate (Au/Si) has higher values of electromotive force, electrical conductivity and power factor as compared to sample grown on ITO substrate, because the sample grown on Au/Si substrate has high density of secondary phases. The presence of secondary phases resulted in the enhancement of Seebeck coefficient and mobility of charge carriers. It is also observed that thermoelectric properties of Zn2GeO4 samples were also improved due to increased of annealing temperature due the emergence of cracks and secondary phases in the annealed samples. This argument was further supported by various characterizations tools. XRD data confirmed the formation of Zn2GeO4 crystal along with the generation of new phases as the annealing temperature increased up to 900 °C. Furthermore, XRD data demonstrated that the sample grown on Au/Si has prominent Zn2GeO4 phases but the sample grown on ITO substrate has weak Zn2GeO4 peak along with ZnO phases. SEM images demonstrated the generation of cracks on the surface of Zn2GeO4 with annealing temperature due to thermal stress. Raman spectroscopy measurements also supported the XRD and SEM results.

Thermodynamic study of the Ag-In-Sn system by the EMF method

The thermodynamic properties of the liquid and solid Ag-In-Sn alloys were determined, using an electromotive force (EMF) method with an eutectic mixture of (KCl + LiCl) as a liquid electrolyte. The measurements were performed over the temperature range from 635 K to 856 K along the cross-sections Ag0.5Sn0.5-In, Ag0.5In0.5-Sn and In0.5Sn0.5-Ag. The partial thermodynamic functions of indium and liquidus temperatures of the investigated alloys were found from the obtained EMF values. The integral thermodynamic properties of alloys at 750 K along the Ag0.5Sn0.5-In cross-section were calculated by Gibbs-Duhem integration.

The thermoelectric sensor for controlling the gas nitriding process

The article describes the concept of the construction and the operating principle of the sensor for controlling the gas nitriding process of iron powders. The detection mechanism is based on Seebeck phenomenon and measurements of thermal electromotive force (EMF). The construction of the sensor refers to thermocouples. The sample iron powder, containing the separated iron and constantan alloy wires, is strongly compressed and constitutes the so called “hot junction” of thermocouple which is connected with “cold junction” – permanently joined both wires, placed in the water with ice (0 °C). During the nitriding process the chemical composition of iron powder (hot junction) changes and as a result a new value of EMF is generated. The change of the EMF signal allows to estimate the progress of the nitriding process. The example of application and the mechanism of the sensor response are proposed.

Modeling and experimental study of a linear power generator for road energy harvesting

There are a large number of vehicles running on the road, and the shape of the road surface varies accordingly. Thus, this kinetic energy can be harvested to power electrical equipment along the road, and this energy harvesting technology has good environmental adaptability because it will not be affected by the sun, wind, or other natural environmental factors. A permanent magnet linear generator is designed and tested for road kinetic energy harvesting. The generator is described by a single degree of freedom system model with mass-spring-damping. The system response is analysed on the basis of the system model. The mover's vibration response is modeled over two stages according to the vehicle's wheel load. The power generation process is simulated and calculated according to the aforementioned models. The magnetic force and magnetic field are calculated by use of the finite element method; because of the non-linear magnetic force, the output electromotive force (EMF) is subject to frequency multiplication under conditions of sinusoidal displacement input. A prototype is manufactured and embedded in the road for experimental research purposes. The test result shows that the maximum peak-to-peak value of the output EMF and average power are up to 484.18 V and 255.1 W, respectively, as a car passes over the generator at a speed 20 km/h. Moreover, the time-domain and amplitude-frequency characteristics agree well with those calculated. It is demonstrated that the proposed model is able to describe the road power generator.

Spontaneous Generation of Electromotive Force in Thin Film Al/Nanosilicon/Al Structures

Contemporary pursuits in electronics include the miniaturization as well as flexibilization of devices. Although there are a large number of different thin and flexible electrochemical batteries, only a few can boast the possibility of working in high humidity conditions. This paper reports on the fabrication of structures consisting of films of silicon nanoparticles encased between two aluminium electrodes. The value of electromotive force (emf) measured depends on the temperature of the sample and on the pressure of water vapor in the storage atmosphere and reaches approximately 1 V. Volt-ampere characteristics were investigated at different conditions to yield a model of emf generation in these structures. It was found that the reaction of water with silicon nanoparticles is the prime reason behind emf generation. Such a source may be introduced into electronic paper, and employed in the next generation of smart cards. The structure may also be manufactured directly on the surface of silicon chips, such as on the back of crystals in microschemes.