Electric Current Intensity Research Articles

Energy performance improvement of a new hybrid PV/T Bi-fluid system using active cooling and self-cleaning: Experimental study

The operating temperature rise and the dust accumulation on the front side of solar panels especially in arid and semi-arid desert areas is a major issue that causes low performance and damage to photovoltaic cells. This experimental investigation aimed to improve the solar panel electrical performance mounted in new hybrid system PV/T Bi-fluid that combines both active cooling and self-cleaning technique simultaneously. This new hybrid system was actively cooled from the backside of the PV module by forced air circulation, while its front side was cooled and cleaned by flowing water. The impact of the operating temperature and global solar radiation intensity on the PV module output voltage, electrical current, electrical power output, and electrical efficiency was evaluated experimentally. Experimental results showed a decreasing linear relationship between electrical efficiency and the increase in PV module’s temperature i.e. reference case without cooling. Up to 15 °C was the average temperature decrease observed in the PV module mounted in the new hybrid system, compared to the reference case. Under the same operating conditions, and at the peak of the global solar irradiation i.e. G = 650 W/m2, an improvement of about 5.7% in electrical efficiency compared to the reference case was obtained. The average overall energy efficiency was found to be 85.3%, while the average exergy efficiency was roughly 14.7%. Several correlations have been proposed for calculation of electric current intensity, electrical energy output, and electrical efficiency, as a function of the average PV module temperature or global solar radiation intensity. A comparison between the reference case and the new hybrid PV/T Bi-fluid system was proved that this new hybrid system was very effective to maintain the electrical efficiency of the PV module at its highest record.

Parallel random bitstreams from a single source of entropy based on nonthermal electrochemical microplasma

AbstractThis study presents the simultaneous generation of two uncorrelated and continuous high‐quality random bitstreams originating from a single physical system based on confined, nonthermal electrochemical microplasma operating under atmospheric conditions. The randomness is intrinsically inherited from the time‐resolved electrical current and optical emission intensities of the microplasma system, which were collected using wide bandwidth current probe and photodetection device. The parallel bitstreams pass unambiguously all 15 NIST SP 800‐22 statistical tests without the need for any data post‐processing. Using the NIST SP 800‐90B package, the min‐entropy estimates of both noise sources were found to be no less than 0.994. This parallel data acquisition can be viewed as a simple strategy to increase the bit generation rate without compromising their quality or adding post‐processing routines.

Degradation of distillery effluent by twisted-type Iron electrodes: experimental with ANN approach

ABSTRACT The distillery spent wash consists of extremely high COD values, high content of pollutants and has an objectionable dark colour. These properties mark the effluent as one of the challenging tasks to treat ahead of exculpating into the surroundings. In this original research work, the raw distillery effluent was electrochemically treated using twisted-type Iron electrodes. Electrochemical treatment was performed for 2 hours and the treated effluent was sampled at defined periods to evaluate the efficiencies of spent wash degradation in terms of colour removal. Optimisation studies were conducted to evaluate the impact of various process parameters viz., applied electric current intensity, pH, mixing speed, electrolysis time and the inter-electrode space on the colour removal efficiencies. The maximum degradation of colour achieved by twisted-type Iron electrodes was found to be 83.75%. Operating conditions at which maximum colour removal efficiencies were achieved at current intensity 1.9 A, pH 3, 2 cm of inter-electrode distance, mixing speed of 100 rpm and for an electrolysis time of 2 h. The experimental results obtained were validated and evaluated using an Artificial Neural Network for modelling and predicting the electrocoagulation process for the degradation of distillery effluent employing twisted-type Iron electrodes.

On the effects of electric current intensity and pulse frequency on the solidified structure of pure aluminum subjected to pulse magneto-oscillation treatment

Pulse magneto-oscillation (PMO) treatment has attracted growing interest as a technique for grain refinement during solidification. Attempts to clarify the effects of PMO treatment parameters have not yet yielded definitive information, because inconsistent results have been reported for the effects of current intensity and pulses frequency on the resulting crystal structures. The present study has investigated the effects of these parameters on the structure of solidified aluminum together with numerical simulations of the effects of electromagnetic field density and applied Lorentz force. It was found that the change in grain size resulting from increasing the electric current intensity, was greater than that resulting from increasing the pulses frequency. However, increasing the current intensity may also increase the induced heat within the charge, thus limiting its refinement efficiency. The simulation calculations showed that once solidification starts, it dramatically decreases the driving force, i.e. the Lorentz force, for grain refinement. This inhibition of the driving force should be taken into consideration in the construction of an efficient electrical system set-up for grain refinement in pure aluminum.

Przebieg prądowy jako źródło informacji o parametrach sterowania wtryskiwaczem paliwowym wtrysku pośredniego

The article discusses results of the laboratory experiments in which fuel injectors used in indirect injection internal combustion engines were tested. During the experiments, numerous dosing cycles of the injectors were performed while changing the control parameters, due to which, the dosing characteristics were developed and influence of applied parameters on the resultant fuel flow determined. Simultaneously, the voltage and electric current waveforms in the injector coil were recorded, due to which finding links between the electric current characteristics and the determinants of the injector work was possible. The investigation has shown that parameters of electric current constitute a precise criterion for assessing the operation of the solenoid valve, because fuel flow is created due to the work ofelectric current. Thus, by observing the changes in the current flowing through the valve coil,it is possible to monitor precisely the correctness of the process of opening the flow and the electric current intensity, at which the flow began and to determine the mechanical quantities such as fuel dose and pressure. As a result, a characteristic is developed, that provides the links between the fuel pressure and the electric current at the point of lifting the needle, which is quite a novel approach. Such a characteristic can be used in diagnostics and control of fuel injectors as well as all kinds of electromagnetic valves

Vibrational and stability analysis of membrane-like current-carrying nanowires under action of longitudinal magnetic fields

The dynamical behavior of a set of nanowires carrying electric current under action of a longitudinally applied magnetic field using the cable model is of our concern. To obtain the nanosystem’s governing equations, we use the Gurtin–Murdoch surface elasticity theory, and by applying the Lorentz formula and the Biot–Savart law, the total Lorentzian force applied on each nanowire from the existing nanosystem and longitudinal magnetic field is appropriately evaluated. Then, using the Galerkin method based on the assumed modes method, we solve the obtained equations of motion for the transverse frequencies. We also calculate the exact vibration modes using the analytical method. The concepts of synchronous and asynchronous vibrational modes are presented, and the validity of the Galerkin method based on the assumed modes is displayed by comparison with the exact approach. Finally, the influences of important parameters such as electric current intensity, magnetic field strength, interwire distance, surface effect, and population of the nanosystem on the free vibration response and the stability of the nanosystem are discussed.

The frictional contact problem of a rigid punch sliding over thermoelectric materials

A theoretical frictional contact model of thermoelectric materials with nonlinear thermoelectric coupling loaded by a sliding punch is considered in which the punch is also assumed to be an electrical and thermal conductor. For the electric fields and the temperature fields, some analytical results are obtained by Fourier transform technique, such as the full field closed-form formulas of the electrochemical potential, the temperature, the electric current density and the energy flux. The distributions of normal electric current density and normal energy flux at subsurface are graphically given. For the elastic fields, the thermoelastic contact problem is reduced to a singular integral equation of the second kind in which thermoelectric effects are reflected in the right end of the resulting equation. The present results demonstrate that the normal electric current density, the normal energy flux and the contact pressure on the contact surface of thermoelectric materials exhibit high singularity in the vicinity of the edges of the punch. Furthermore, the effects of the friction coefficient and the thermoelectric loads on the critical stresses, the electric current density intensity factor, the energy flux intensity factor and the stress intensity factor are provided. The finding of the presented model is helpful for accessing the surface wear resistance of thermoelectric materials.

Dry Magnetic Separation on the Recovery of Metal Fragments from Kerf Slurry Waste Produced during the Manufacture of Photovoltaic Solar Cells

In the interest of reducing the cost of photovoltaic production while preserving the environment, a sawing rejection treatment was carried out by recovering the metals with an efficiency estimated to be 96%. To achieve this outcome, first, the sawing rejection was washed with acetone to dissolve the polyethylene glycol. It was then dried in an oven at 70 °C to obtain a slurry powder. This later, powder has undergone a dry magnetic separation under different electric current intensity to recover metals. The metal-containing phase has been characterized by the X-ray diffractometer and the scanning electron microscope. Finally, a simulation on the recovery of metal fragments in the slurry generated during the manufacture of photovoltaic briquettes.

A Pair of Conjugate Current Ribbons Coinciding with the Double-ribbon Flare

Using the vector magnetograms observed by SDO (Solar Dynamics Observatory)/HMI (Helioseismic and Magnetic Imager), the current distribution and evolution associated with an X9.3 flare occurred in the active region AR12673 on Sept. 6, 2017 are studied in detail. The results show that there is a pair of electric current ribbons with opposite directions and the magnitude of 0.4 A/m2, which can be called a pair of conjugate electric current ribbons. This pair of conjugate electric current ribbons exist before, during, and after the flare; their positions are almost coincident with the two bright ribbons of the flare, and their shapes are also extremely similar with them. The light curve of the total electric current intensity on Sept. 6 shows that the electric current intensity enhanced sharply during the strong X9.3 flare eruption, and this phenomenon persisted for several hours. The results of this study strongly support the model of QSL (Quasi-Separatrix Layer) 3D magnetic reconnection.

Neural networks technique for detecting current systems while main phase of geomagnetic storm

The study demonstrated the technology for searching nonlinear correlations between the intensity indices of auroral electric jets (AU, AL) and ring current intensity indices (SYM, ASY). The well-known connection of the western electrojet with the asymmetric part of the ring current and the eastern electrodett with the symmetric is confirmed. The technology of artificial neural networks was chosen as the main method. Thus, the relationship of magnetic disturbances in the auroral region and magnetic disturbances at middle and low latitudes in the main phase of a geomagnetic storm is investigated. The characteristic lead times in the development of mid-latitude magnetospheric processes relative to polar are determined. An acceptable neural network recovery of auroral electrojet intensity indices from ring current index data is demonstrated.

Assessment of Low Electric Current Intensities, Exposure Time and Electrodes Distance Effects on Bacterial Quantity in un-Chlorination Water

Assessment of Low Electric Current Intensities, Exposure Time and Electrodes Distance Effects on Bacterial Quantity in un-Chlorination Water

Study on the effect of electric current intensity stimulation combined with biofeedback pelvic floor muscle training on postpartum pelvic floor dysfunction

Aim: To explore the effect of different electrical stimulation intensities combined with pelvic floor muscle training on postpartum pelvic floor dysfunction. Methods: 720 patients with pelvic floor dysfunction diagnosed following vaginal delivery were randomly divided into intervention and control groups. The control group was treated with conventional electrical stimulation combined with pelvic floor muscle training. Patients in the intervention group were treated with electrical stimulation of increasing intensity. The electrophysiological indices of pelvic floor function, SUI incidence, ICI-Q-SF, POP-Q, PFIQ-7 and PISQ-12 scores were compared between the two groups. Results: Following treatment, patients in the intervention group had significantly higher pelvic floor muscle type I, type II muscle strengths, slow muscle average myoelectric values, fast muscle maximum myoelectric values, front resting average myoelectric values, rear resting average myoelectric values, and vaginal resting pressure, compared to the control group. There was no difference in the Bp, D, GH, PB and TVL measurements between the two groups. SUI, ICI-Q-SF and PISQ-12 scores were significantly lower in the intervention group, but there was no difference in the PFIQ-7 score. Conclusion: Use of higher intensity electric stimulation combined with pelvic floor muscle training appears to improve the electrophysiological indices of pelvic floor function and POP-Q parameters, as well as reducing the severity and incidence of urinary incontinence and improving sexual function.

Scaling up the electrokinetic-assisted phytoremediation of atrazine-polluted soils using reversal of electrode polarity: A mesocosm study

Electrokinetic-assisted phytoremediation (EKPR) has been recently proposed for the removal of pesticides from polluted soils. In this work, we report the results from an EKPR experiment that was carried out in a mesocosm mock-up of 0.386 m3 using ryegrass (Lolium perenne L.) and a low permeability soil spiked with atrazine. Plants were initially grown for 35 days; then, the soil was spiked with atrazine at a dose of 2 mg kg−1 soil. A DC electrical field of 0.6 V cm−1 was applied 24 h every day, switching polarity daily. Another identical mock-up with the same experimental conditions but without plants was used for comparison purposes. The duration of the EKPR test was 19 days during which some operational parameters were registered (electric current intensity, soil pH and temperature) and soil porewater samples were taken and analysed. Plant tissues and soil samples from the different sections in which the mock-ups were divided, were also collected and analysed at the end of the experiment. 3-D profiles of soil pH, water content and atrazine residues concentration in plants and soil were obtained and discussed. The results of this experiment were compared with others previously reported by us from a similar EKPR pot test. In spite of the difficulties to get an adequate geometric and operational similarity between setups of different scale, the main output parameters of the EKPR process (electric current, specific current charge, overall atrazine removal, specific atrazine removal efficiency, root biomass:soil weight ratio) were discussed. It was shown that, although the processes carried out are essentially the same in both scales, their extent may be quite different; it highlights the limitations of small-scale experiments to predict the results at field conditions.

Silica extraction from hydrothermal heat carrier by coagulation

We have carried out the experiments on coagulation and precipitation of silica from the separate of Verkhne-Mutnovsky geothermal electric power plant (Mutnovskoe hydrothermal field). Silica precipitation from the water solution was conducted in two ways: by adding slaked lime CaO and by electrocoagulation treatment on aluminium electrodes. Silica precipitation with addition of slaked lime was carried out under laboratory conditions at the temperature of 20 and 96 °C. Colloid and monomeric silica concentrations, solution pH, flakes sizes and physical-chemical properties of material precipitated with different quantities of added lime were determined. We also carried out series of experiments on solution treatment of mixed type: addition lime with freshly precipitated flakes, and addition lime with sea water. In the experiments on electric coagulation, current intensity and distance between electrodes were changed. Dependence of silica concentration on treatment duration was studied. Quantities of electric energy and anode aluminium consumed for reducing of silica concentration to a certain level were obtained. The results of our experiments can be used for developing of technological scheme of silica precipitation and utilization optimal for Verkhne-Mutnovsky geothermal electric power plant.

Nonlinear numerical analysis of a thin current-carrying frustum shell based on magnetic-mechanical coupling

A nonlinear magnetoelastic problem for a thin current-carrying frustum shell under the interaction of an electromagnetic field and a mechanical field is studied, and the numerical calculation method is given. The magnetoelastic basic equations of the thin frustum shell are derived. The linearized iterative equations are developed. The stresses and deformations in a thin current-carrying frustum shell under the interaction of electromagnetic field and mechanical loads are calculated by considering a specific example. The magnetoelastic effect on the thin frustum shell by electric current density and magnetic induction intensity is studied. The results show that the stresses and deformations in thin shells can be controlled by changing electric current density or magnetic induction intensity.

Oxygen-Resistant Electrochemiluminescence System with Polyhedral Oligomeric Silsesquioxane.

We report the oxygen-resistant electrochemiluminescence (ECL) system from the polyhedral oligomeric silsesquioxane (POSS)-modified tris(2,2′-bipyridyl)ruthenium(II) complex (Ru-POSS). In electrochemical measurements, including cyclic voltammetry (CV), it is shown that electric current and ECL intensity increase in the mixture system containing Ru-POSS and tripropylamine (TPrA) on the indium tin oxide (ITO) working electrode. The lower onset potential (Eonset) in CV is observed with Ru-POSS compared to tris(2,2′-bipyridyl)ruthenium(II) complex (Ru(bpy)32+). From the series of mechanistic studies, it was shown that adsorption of Ru-POSS onto the ITO electrode enhances TPrA oxidation and subsequently the efficiency of ECL with lower voltage. Moreover, oxygen quenching of ECL was suppressed, and it is proposed that the enhancement to the production of the TPrA radical could contribute to improving oxygen resistance. Finally, the ECL-based detection for water pollutant is demonstrated without the degassing treatment. The commodity system with Ru(bpy)32+ is not applicable in the absence of degassing with the sample solutions due to critical signal suppression, meanwhile the present system based on Ru-POSS was feasible for estimating the amount of the target even under aerobic conditions by fitting the ECL intensity to the standard curve. One of critical disadvantages of ECL can be solved by the hybrid formation with POSS.

Effect of external electric current on adsorption of lead by Penicillium polonicum

Lead is a major source of environmental pollution that has recently been the focus of a great deal of research. Bioremediation has been shown to be effective in remediation of lead pollution. Penicillium polonicum is a fungus with highly efficient adsorption of lead. In this study, the influence of electric current on the growth characteristics and adsorption of lead by the strain were investigated through applying different external voltages (1.5, 1.25, 1.0, 0.75, and 0.5 V). The results indicated that the electric current with voltage ranges from 1.0 to 1.25 V could promote the adsorption of lead. In addition, morphological characteristics and the quantity of lead-containing minerals formed on the surface of P. polonicum differed greatly under different experimental conditions. Further, the electric current intensity and electric energy consumption at voltages of 1.0, 1.25, and 1.5 V were higher than the blank control group, suggesting that the strain could utilize the energy supplied by an external electrochemical workstation to improve lead adsorption. After applying an external current, the lead adsorption of P. polonicum was affected by electric current changing the growth environment of the fungus and the electron transfer reaction between electrodes and P. polonicum.

(Invited) Ultra-Low Power Light Emission Via Avalanche and Sub-Avalanche Breakdown in Suspended Carbon Nanotubes

We report near-infrared light emission in suspended carbon nanotube field effect transistors over a wide range of gate and bias voltages. An abrupt increase in both the electric current (90 μA/V) and electroluminescence intensity is observed at high bias voltages (∼3.5 V), when gated in the “off’ state (i.e., Vgate > 0 V). For bias voltages below the threshold for avalanche breakdown, we observe light emission due to the creation of exitons by impact ionization under these high electric fields. Here, we find that there is a relatively small region over which low power (∼nW) light emission is observed. By plotting the relative luminescence efficiency (i.e., light intensity/electrical power) as a function of the gate and bias voltages, we observe a very sharp feature corresponding to avalanche emission at which the electroluminescence efficiency is 2−3 orders of magnitude higher than that under all other conditions of gate and bias voltage. A steep increase in the current with bias voltage (i.e., large dI/dVb) is observed at the same gate and bias conditions of the highly efficient electroluminescence and signifies the onset of the avalanche process. We believe that these results demonstrate additional mechanistic evidence for achieving highly efficient light emission in carbon nanotubes via avalanche breakdown.

Continuous electrochemical reactor improved by the addition of Moringa oleífera lam extract: optimization of operational conditions for Blue 5G dye removal

Wastewaters from textile industries are known for their difficulty to treat, several alternative technologies are applied for their treatment. In this context, the study examined a hybrid treatment system, composed of electrocoagulation combined with a natural coagulant (extract of Moringa oleífera lam seeds) to remove reactive dye Blue 5G aqueous solutions. The work evaluated the use of milder operating conditions to improve the efficiency of treatment, with reduced demands for electrical power and coagulant. The following factors were evaluated: electric current intensity, natural coagulant concentration and hydraulic retention time. A quadratic model was adjusted and validated at a 5% significance level. The overall optimization resulted in conditions of 0.28 A for electrical current intensity, 1000.00 mg L-1 of aqueous extract of Moringa oleífera lam and 5 min for hydraulic retention time. While operating under optimal conditions, the removal of 71.38% of color and 5.22 mg L-1 of iron residual concentration was achieved.

Effect of iontophoresis on fluoride uptake in enamel with artificial caries lesion.

Iontophoresis is a noninvasive technique, based on the application of a constant low-intensity electric current to facilitate the release of a variety of drugs, whether ionized or not, through biological membranes. The objective of this research was to evaluate the effect of iontophoresis using different electric current intensities on the uptake of fluoride in dental enamel with artificial caries lesions. In this in vitro operator-blind experiment, bovine enamel blocks (n = 10/group) with caries-like lesions and predetermined surface hardness were randomized into 6 groups: placebo gel without fluoride applied with a current of 0.8 mA (negative control), 2% NaF gel without application of any current, and 2% NaF gel applied with currents of 0.1, 0.2, 0.4 and 0.8 mA. Cathodic iontophoresis was applied for 4 min. The concentration of loosely bound fluoride (calcium fluoride) and firmly bound fluoride (fluorapatite) was determined. The results were analyzed by the nonparametric Kruskal-Wallis and Dunn tests. Iontophoresis at 0.8 mA, combined with the application of fluoridated gel (2% NaF), increased fluoride uptake in enamel with caries-like lesions, as either calcium fluoride or fluorapatite.