Increase Of Discharge Time Research Articles

Elman neural network-based temperature prediction and optimization for lithium-ion batteries

Reliable and precise temperature prediction is one of the most crucial challenges for improving battery performance and preventing thermal runaway. This paper uses a highly adaptive Elman neural network (Elman-NN) to construct a temperature prediction model for lithium-ion batteries in a metal foam aluminum thermal management system. Numerical modeling methods obtain experimental data sets for model training and testing. The input parameters of the neural network prediction model are ambient temperature, battery discharge rate, cooling air flow rate, and state of charge; the output parameters are the maximum, minimum, and average battery temperature. However, due to the limitations of the gradient descent algorithm, the training process of the Elman neural network tends to fall into local optimum solutions. To further improve the prediction accuracy, the Elman-NN structure was optimized using the PSO algorithm, and the model performance was tested and validated. Compared with the original Elman-NN, the hybrid PSO-Elman-NN has smaller MSE and MAE values, with a maximum reduction of 43% and 25%, respectively. For the three test conditions, the maximum predicted temperature difference does not exceed 1.5 K, and the temperature difference decreases further as the discharge time increases. Moreover, the hybrid model’s prediction accuracy is significantly improved, with the coefficients of determination ( R2) increasing by 1.736%, 0.706%, and 1.851%, respectively. The PSO-Elman-NN performed well in terms of compatibility and accuracy of the battery temperature prediction.

Geometrical Parameter Effects on Solidification/Melting Processes Using Twin Concentric Helical Coil: Experimental Investigations

Moving the load peak to consume electrical power is valuable in air conditioning systems. Consequently, the current study presents an experimental thermal investigation of an ice storage system. For this purpose, a twin concentric helical coil (TCHC) is utilized. The coil is submerged in distilled water in an insulated tank. The main aim is to explore the effect of geometrical/operating conditions for the TCHC on percentage energy stored/regained, solidified/melted mass fraction, and average charging/discharging rate. The main parameters are twin coil pitch and tube diameter while keeping the cold heat transfer fluid (HTF) inlet conditions at −12 °C and 10 L/min. The results disclosed that the discharge time increases by about 79% for total energy gained as the coil pitch rises from 30 to 50 mm at a smaller tube diameter of 9.52 mm. At the same time, the discharge time is doubled when the tube diameter is 15.88 mm. Furthermore, the complete solidification needs half the time (time reduced to 50%) to be achieved as the tube diameter increases from 9.52 mm to 15.88 mm (68% increases in diameter) for lower pitch (P = 30 mm).

Effects of induced electro-pulsing and aging process on properties and microstructure of 7075 aluminum alloy

The effect of induced electro-pulsing of 7075 aluminum alloy in solid solution and pre-deformation was studied. The tensile test results show that material plasticity is recovered and strength is increased by induced electro-pulsing treatment (IEPT). As the discharge time increases, the increase in elongation becomes more obvious. Yield strength, tensile strength, and elongation of once-treated samples increased by 3.7%, 1.3%, and 9.7%, respectively, compared with the untreated sample; Those of twice-treated samples increased by 6.4%, 6.4%, and 27.8%. Microstructure characterization showed that the induced current reduces the dislocation density of the material and promotes advanced precipitation of Guinier-Preston (GP) zones. In addition, the strength of treated samples and untreated samples was almost the same after peak aging treatment, while the elongation increased by 12.15%. High resolution transmission electron microscopy (HRTEM) images show that the size of the η’ phase in the treated alloy is smaller and the alloy exhibits better ductility.

Corrosion protection of magnesium alloys anode by cerium-based anodization coating in magnesium-air battery

CeN3O9·6H2O (0.5, 1.0, 1.5, and 2.0 g/L) was added into an 8.0% NaCl electrolyte solution to investigate this electrolyte for use in a Mg-air battery. The effects of the amount of CeN3O9·6H2O on the corrosion resistance of an AZ31 Mg alloy anode and battery performance were investigated using microstructure, electrochemical (dynamic potential polarization method and electrochemical impedance spectroscopy), and battery measurements. The results show that the addition of CeN3O9·6H2O to the electrolyte leads to the formation of a Ce(OH)3 protective film on the surface of the AZ31 Mg alloy that improves the corrosion resistance of the Mg alloy. An increase in the concentration of CeN3O9·6H2O results in a denser Ce(OH)3 protective film and decreases corrosion rate of the AZ31 Mg alloy. When the concentration of CeN3O9·6H2O is 1.0 g/L, the corrosion rate of the Mg alloy is the lowest with a corrosion inhibition rate of 70.4%. However, the corrosion rate increases due to the dissolution of the Ce(OH)3 protective film when the concentration of CeN3O9·6H2O is greater than 1.0 g/L. Immersing the Mg alloy in the electrolyte solution containing CeN3O9·6H2O for 50 h leads to the formation of the Ce(HO)3 protective film on its surface, which was confirmed by scanning electron microscopy of the AZ31 alloy. The Mg2+ charge transfer resistance increases by 69.5 Ω from the equivalent circuit diagram, which improves the corrosion resistance of the Mg alloy. The discharge performance of CeN3O9·6H2O improves according to a discharge test, and the discharge time increases by 40 min.

Decomposition characteristics and marker products of C3F7CN/EP insulation system with long-term surface discharge

C3F7CN has the potential to replace SF6 in gas insulated equipment due to its excellent insulation properties and low GWP. In order to apply better use of C3F7CN gas in the future, it is of great significance to study the reaction products of C3F7CN and epoxy resin (EP) with discharge failure conditions for online monitoring and insulation evaluation. In this paper, the experiments of gas–solid interface discharge for 300 h were carried out. The gas decomposition products were tested by GC–MS, the elements and chemical bonds on the surface of EP before and after discharge were tested by FTIR and XPS. The results showed that the number of gas decomposition products increased with the increase of discharge time. The products mainly included saturated carbon–fluorine gas CF4, C3F8, and C6F14, unsaturated carbon–fluorine gas C3F6, C4F6, and C4F8, nitrile gas CF3CN, ester gas C12F7H17O2, among which C12F7H17O2 was the marker product of C3F7CN/EP. And the relative contents of CF4 and C3F8 increased linearly with the increase of discharge time. The growth rates of C4F10, C4F8, C3F6 and C6F14 increased firstly and then decreased. After discharging on the gas–solid insulating surface, F and N elements in the gas appeared on the EP surface in the form of CF bond and CN bond. Further analysis of the products, a mathematical model for the variation of product formation rate with discharge time was proposed. Finally, it was proposed that C12F7H17O2 was a marker product for diagnosing discharge decomposition of C3F7CN/EP resin insulation system.

On the forming uniformity during a single layer forming of electromagnetic incremental forming

Aiming to the precise control of forming quality in electromagnetic incremental forming (EMIF), deformation behaviors of a spherical crown-shaped thin-walled workpiece during a single layer forming of EMIF are analyzed by means of numerical simulation. The influences of the coil overlap ratio, coil moving strategy, and discharge voltage combination on the forming uniformity of the workpiece are revealed. The maximum electromagnetic force and forming depth represent a “dramatic decrease–long-term steady–moderate decrease” variation over the increase of discharge time for forming a single layer by sequential discharging. The difficult-to-deform region located outside the overlap region of coil positions deforms insufficiently, leading to poor overall uniformity. Better uniformity and higher forming efficiency are achieved by sequential discharging compared with interval discharging. With an increase in the coil overlap ratio, the circumferential uniformity of the workpiece is improved because the transition deformation region is reduced and the active deformation region subjected to electromagnetic force is increased. In addition, the forming uniformity of the workpiece can be improved significantly by an optimized discharge voltage combination with properly decreased first discharge voltage and increased last discharge voltage, respectively. A forming scheme for a spherical crown-shaped thin-walled workpiece is proposed based on the forming principles and a workpiece with high precision and good uniformity is obtained. Therefore, EMIF is demonstrated as capable to form high precision large-size thin-walled parts.

Decomposition products and formation path of C3F7CN/CO2 mixture with suspended discharge

A mixture of perfluoronitrile (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN) and carbon dioxide (CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) has excellent insulation and environmental protection properties, and it is considered to have the potential to replace SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> gas. However, there are few studies on the decomposition products and formation reasons of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas under partial discharge. In order to study the decomposition characteristics of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas, suspension potential was used to simulate partial discharge. The experimental study on partial discharge decomposition of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas was carried out. The variation of decomposition products with discharge time was qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry (GC/MS). The results show that the decomposition products of suspension discharge of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> are mainly CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> , C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sub> , CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CN and an unknown product. The relative contents of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> remain basically unchanged with the increase of discharge time. The relative contents of CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sub> and unknown products show a non-linear growth trend with the increase of discharge time. The relative content of CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CN gas shows a saturation trend with the increase of discharge time. Finally, based on density functional theory (DFT), the formation paths of various products are analyzed.

A real‐time experimental investigation of building integrated thermal energy storage with air‐conditioning system for indoor temperature regulation

AbstractIn this article, a novel concept of the latent heat thermal energy storage system combined with the conventional cooling system is proposed for the application of indoor thermal comfort. Lauryl alcohol with a melting point of 22‐25°C is selected as phase change materials (PCM) for the study. From the results of experiment conducted with different mass of PCM, there is no change in temperature drop achieved while increasing PCM mass but there is increase in discharge time. The average air temperature in bottom chamber is maintained at 26°C which is in thermal comfort range throughout the experiment. For the experiments with different inlet air temperatures, higher drop in top chamber outlet air temperature is achieved for higher inlet temperatures. The temperature of the room can bring down to human thermal comfort range with a minimum duration of time with the proposed system irrespective of initial room temperature. The proposed system helps to maintain the buildings in human thermal comfort range with less‐energy consumption when the conventional air‐conditioning system is not in operation which in turn decreases the major energy consumption by the building sector through other auxiliary energy source.

Hydrogen production from ethanol decomposition by pulsed discharge with needle-net configurations

Hydrogen produced from ethanol solution by pulsed discharge was investigated in this work. With needle-net configurations, hydrogen can be easily exported from the plasma reactor thereby preventing hydrogen from consuming by the oxidizing active substances generated from pulsed discharge. Both flow rate and percentage concentration of hydrogen were enhanced with the increase of energy density, but not much change with the increase of discharge time. Flow rate, percentage concentration, and energy consumption of hydrogen were achieved about 800mL/min, 73.5%, and 0.9kWh/m3 H2 respectively with energy density of 6.4J/L. All products were analyzed, which were divided into main and secondary products guiding the mechanism analysis of hydrogen production. The main products contain H2, CO, CH3OH, and the secondary products include C2H2, CO2, macromolecular compounds, nano carbon particles. The high hydrogen yield, emerged nano carbon, low ethanol and energy consumption make this method possess bright prospect in hydrogen production.

Bacteria sterilization application by using plasma activated physiological saline

The plasma activated water has great application prospects in the fields of environmental protection, biomedicine, food safety, et al., due to its unique chemical activity. In this work, the plasma activated physiological saline is successfully generated by using hollow fiber-based cold microplasma jet array running in physiological saline solution. This design can lead to an obvious increase in the contact area between microplasmas and treated physiological saline solution, thus improving the chemical reaction efficiency of short-lived species. The influences of working gases such as He, N2, O2 and air on the sterilization efficiency of E. Coli by using this plasma activated physiological saline are investigated as a function of discharge time. As the discharge time increases from 10 to 180 s, the sterilization efficiency of the plasma activated physiological saline significantly increases. It is found that the bactericidal efficiency of the air discharge activated physiological saline is highest. For a discharge time of 120 s, the sterilization efficiency of E. Coli in this plasma activated physiological saline can reach as high as 99.999%. The pH value of this air discharge activated physiological saline is achieved by using acidity meter and as the discharge time increases from 10 to 60 s, the pH value decreases from 7.3 to 3.1 and the physiological solution becomes acidic. This may be due to the NOX produced in the plasma reacting with water and producing nitric and nitrate acids. The reactive oxygen species generated in the plasma activated physiological saline are supposed to be O3 and H2O2. The concentrations of O3 and H2O2 are identified by using UV-visible absorption spectra and chemical deposition methods. The strong absorption peak of O3 in UV-visible absorption spectrum is at a wavelength of 253.7 nm. The concentration of O3 is calculated by using Beer-Lambert Law. As the discharge time increases, the concentration of O3 in the plasma activated physiological saline obviously increases. For a discharge time of 60 s, the concentration of O3 is 43.1210-3 mol/L and nearly saturated. The concentration of H2O2 is obtained by the total amount of reactive oxygen species, which is calculated by using the chemical deposition method, deducting the O3 content. As the discharge time increases from 10 to 180 s, the concentration of H2O2 increases from 1.510-3 to 4.710-3 mol/L. The analyses of experimental data from various methods indicate that air discharge activated physiological saline containing a variety of long-lived reactive oxygen species, such as H2O2 and O3, is very effective in killing E. Coli cells in the acidic saline solution. The air discharge activated physiological saline can provide a means to store the advanced oxidation species induced by the discharge for sterilization applications.

Effect of Low-voltage Pulse on Cell Elimination

Abstract The low electric field application to HeLa cells adhered to electrodes was studied to induce cell death effectively. The low-voltage pulse applied to the electrode was generated with charge and discharge by an originally made circuit. The unique characteristics in this experiment is the charge flow between electrodes, and it causes direct attack of the ions to the cell membrane, leading to complete cell elimination. Viability of cells appreciably decreased with increase in discharge time at a quite low 3 V cm−1 that has not been reported to date.

Solution plasma for template removal in mesoporous silica: pH and discharge time varying characteristics

The evaluation of the ability of solution plasma process, SPP, depending on the pH of the discharge solution and discharge time for template removal in mesoporous silica was described. In the synthesis of mesoporous silica, ternary surfactant system containing tri-block copolymer EO 20PO 69EO 20 (P123), sodium dodecylbenzene sulfonate (SDBS), and 1,1,2,2,3,3,4,4,4-nonafluoro-1-butyl sulfonate (NFBS) was chemically used for synthesis under acid condition via sol–gel method then SPP was employed for template removal. The ordered 2D hexagonal arrangement was observed by the evidence of high resolution TEM and the diffraction mode of X-ray. The efficiency of SPP depending on the pH of the discharge solution and discharge time was scientifically demonstrated as a function of BET surface area. In the case of pH dependence, it was achieved that the ability of template removal in acid and base solutions was clearly higher than those of such results in neutral solution. In the term of discharge time, moreover, the percentage of template removal comparing in the result of BET surface area increased as the increase in discharge time.

Electrochemical Performance of Microbial Fuel Cell with Air-Cathode

In order to promote the energy output of microbial fuel cell (MFC), reduce the internal resistance of MFC and the cost of processing organics, a direct-air cathode single-chamber microbial fuel cell was constructed by using air electrode as cathode, foamed nickel (ferrumiron) as anode and glucose as the anode fed. The results demonstrated that the open circuit voltage reached 0.62 V, the internal resistance of the cell was 33.8 Ω, the maximum power density reached 700 mW·m-2 (4146 mW·m-3), and the electron recovery was 20%. The discharge curve and cyclic voltammetry tests revealed that the first discharge capacity and energy density were 263 mAh·g-1 COD (chemical oxygen demand) and 77.3 mWh·g-1 COD, respectively. The charge-discharge performance and stability of MFC were pretty good. The electrochemical impedance spectroscopy analysis demonstrated that the cell impedance increased with the increase of discharge time, which was one of the reasons resulting in the decrease of output voltage. The degradation rate of COD (chemical oxygen demand) reached 56.5% after it operating for 8 h. The degradation of COD followed the first order reaction model.

Photoluminescence from Thermally Oxidized Hydrogenated Amorphous Silicon Nanoball Films Fabricated by Double-Tubed-Coaxial-Line-Type Microwave Plasma Chemical Vapor Deposition System

Using a double-tubed-coaxial-line-type microwave plasma chemical vapor deposition (MPCVD) system, hydrogenated amorphous silicon (a-Si:H) nanoball films, which include Si nanocrystals, can be fabricated. A high deposition rate of 1600 Å/s is achieved at a gas flow rate of 30 ml/min. Photoluminescence (PL) around 780 nm is observed at room temperature after the a-Si:H nanoball film is thermally oxidized in air or in pure oxygen gas. We have fabricated thermally oxidized a-Si:H nanoball films under various fabrication and oxidation conditions. As the substrate temperature during deposition becomes higher, the PL intensity decreases, and PL cannot be observed above 200°C. The PL intensity is the strongest when the substrate is set about 6 cm from the discharge tube end. As the discharge time increases, the film thickness increases and saturates, and consequently the PL intensity increases and also saturates.

A study of Fluorination of Graphite by Electric Glow Discharge

Experiments on the surface fluorination of graphite electrodes were made in a low pressure glow discharge. Three gases were used in the discharge : SF6, CF4, and CF2Cl2. High voltage AC and DC were directly applied between the graphite and an aluminum counter electrode. After the discharge, measurements of the contact angle of the graphite surface were made by the drop method. The drop contact angle relates to the degree of surface fluorination. Only CF4 caused a significant increase of the drop contact angle related to the above listed gases. When the graphite surfaces were observed by a scanning electron microscope, thin solid products were found. These products were shown to be fluorographite by ESCA analysis. However, the mass of the graphite electrode decreased with increase of discharge time, an unexpected result.It seemed that the graphite fluorination reactions in the discharge were carried out through parallel reaction paths in a fluorographite (solid) and a fluorocarbon (gas) producing process.

Initiation criteria for diverging gaseous detonations

Further experiments on the direct initiation of spherical detonation waves in oxy-acetylene mixtures in the pressure range 20–120 torr have been carried out with detailed monitoring of the time history of the energy deposition. The magnitude of the spark energy required for direct initiation is found to depend on the discharge time, increasing in magnitude as the discharge time increases. For a fixed discharge time, the dependence of the magnitude of the source energy is found to be inversely proportional to the mixture composition. On the basis of an average power density correlation [i.e., (total spark energy/(total discharge time) × (source volume)], the discrepancies in the magnitude of the critical initiation energy can be resolved. The order of magnitude of the critical power density required for direct initiation is found to be of comparable order of magnitude as the power density of a self-sustained detonation wave. The dependence of the critical power density on initial pressure is similar to that obtained previously based on source energy (i.e., increases with decreasing pressure or increasing induction delay). Since the power density itself cannot be a meaningful parameter as the source energy can be made vanishingly small with an appropriate reduction in the discharge time or source volume or both, it is proposed that the critical energy in the limit of infinite power density should be used as the universal parameter to correlate with the properties of the explosive mixture. In view of the good agreement between the ideal-point-blast theory and experiments on laser-generated blast waves, even at very early times after the termination of the laser pulse, we concluded that the experimental value of the critical energy using a laser spark should represent the limiting value at infinite power density. A phenomenological model is proposed to gain physical insight into the coupling mechanisms between chemical kinetics and hydrodynamics in a transient flow structure such as that of the spherical wave. The coupling mechanisms are modelled by a global function which leads to an effective energy release at the front which is independent of either the local shock strength or the shock radius. The model recovers the essential features of the three propagation regimes of the reacting blast corresponding to different magnitudes of the source energy. Particularly interesting is the theoretical prediction that unless the source energy is very large, the reacting blast first decays to sub-Chapman-Jouguet velocity and then approaches its final C-J conditions extremely slowly. This prediction finds experimental confirmation in the experimental work of Struck and Brossard. Using an experimentally determined induction-zone thickness of the order of magnitude of the recently defined hydrodynamic thickness, quantitative results on the critical energy as well as transverse wave spacings from the present model were found to agree unexpectedly well with experiments.