J. M. Losada, A. D. Helgeland, J. L. Terry, O. E. Garcia
Time delay and velocity estimation methods have been widely studied subjects in the context of signal processing, with applications in many different fields of physics. The velocity of waves or coherent fluctuation structures is commonly estimated as the distance between two measurement points divided by the time lag that maximizes the cross correlation function between the measured signals, but this is demonstrated to result in erroneous estimates for two spatial dimensions. We present an improved method to accurately estimate both components of the velocity vector, relying on three non-aligned measurement points. We introduce a stochastic process describing the fluctuations as a superposition of uncorrelated pulses moving in two dimensions. Using this model, we show that the three-point velocity estimation method, using time delays calculated through cross correlations, yields the exact velocity components when all pulses have the same velocity. The two- and three-point methods are tested on synthetic data generated from realizations of such processes for which the underlying velocity components are known. The results reveal the superiority of the three-point technique. Finally, we demonstrate the applicability of the velocity estimation on gas puff imaging data of strongly intermittent plasma fluctuations due to the radial motion of coherent, blob-like structures at the boundary of the Alcator C-Mod tokamak.
{"title":"A three-point velocity estimation method for two-dimensional coarse-grained imaging data","authors":"J. M. Losada, A. D. Helgeland, J. L. Terry, O. E. Garcia","doi":"10.1063/5.0197251","DOIUrl":"https://doi.org/10.1063/5.0197251","url":null,"abstract":"Time delay and velocity estimation methods have been widely studied subjects in the context of signal processing, with applications in many different fields of physics. The velocity of waves or coherent fluctuation structures is commonly estimated as the distance between two measurement points divided by the time lag that maximizes the cross correlation function between the measured signals, but this is demonstrated to result in erroneous estimates for two spatial dimensions. We present an improved method to accurately estimate both components of the velocity vector, relying on three non-aligned measurement points. We introduce a stochastic process describing the fluctuations as a superposition of uncorrelated pulses moving in two dimensions. Using this model, we show that the three-point velocity estimation method, using time delays calculated through cross correlations, yields the exact velocity components when all pulses have the same velocity. The two- and three-point methods are tested on synthetic data generated from realizations of such processes for which the underlying velocity components are known. The results reveal the superiority of the three-point technique. Finally, we demonstrate the applicability of the velocity estimation on gas puff imaging data of strongly intermittent plasma fluctuations due to the radial motion of coherent, blob-like structures at the boundary of the Alcator C-Mod tokamak.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"13 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The integration of electric vehicles (EVs) is becoming vital for both the transportation and energy sectors. At the same time, they need an appropriate charging facility. Photovoltaic (PV) powered electric vehicle chargers are gaining popularity since they require negligible maintenance and steadily enhance the efficiency of PV modules. In this paper, a grid tied solar PV with a 12 pulse Line Commutated Converter (LCC) based off board EV charger is presented. The specialty of the proposed method is that it does not require an extra controller for ac grid synchronization. In addition, simplified maximum power point tracking (MPPT) control is proposed, which will track the MPP of the PV array. The main disadvantage of LCC is its poor harmonics profile, which can be improved by a higher pulse number with adequate phase shift. With 12 pulse LCC, high characteristics harmonics are greatly reduced. The performance and efficacy of the suggested method have been confirmed by simulation, which proves the feasibility of the proposed solution for EV charging in both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes.
{"title":"A grid tied solar photovoltaic based off board electric vehicle charger in G2V and V2G mode","authors":"Jyoti M. Kumbhare, Sumant G. Kadwane","doi":"10.1063/5.0212427","DOIUrl":"https://doi.org/10.1063/5.0212427","url":null,"abstract":"The integration of electric vehicles (EVs) is becoming vital for both the transportation and energy sectors. At the same time, they need an appropriate charging facility. Photovoltaic (PV) powered electric vehicle chargers are gaining popularity since they require negligible maintenance and steadily enhance the efficiency of PV modules. In this paper, a grid tied solar PV with a 12 pulse Line Commutated Converter (LCC) based off board EV charger is presented. The specialty of the proposed method is that it does not require an extra controller for ac grid synchronization. In addition, simplified maximum power point tracking (MPPT) control is proposed, which will track the MPP of the PV array. The main disadvantage of LCC is its poor harmonics profile, which can be improved by a higher pulse number with adequate phase shift. With 12 pulse LCC, high characteristics harmonics are greatly reduced. The performance and efficacy of the suggested method have been confirmed by simulation, which proves the feasibility of the proposed solution for EV charging in both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"6 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chao-Ching Chiang, Jian-Sian Li, Hsiao-Hsuan Wan, Fan Ren, Stephen J. Pearton
The use of the low work function (4.5 eV) tungsten (W) as a rectifying contact was studied to obtain low on-voltages in W/Ga2O3 Schottky rectifiers and NiO/Ga2O3 heterojunction rectifiers that were simultaneously fabricated on a single wafer. The devices were produced with varying proportions of relative areas and diameters, encompassing a spectrum from pure Schottky Barrier Diode (SBD) to pure Heterojunction Diode (HJD) configurations. The turn-on voltages with W contacts ranged from 0.22 V for pure Schottky rectifiers to 1.50 V for pure HJDs, compared to 0.66 and 1.77 V, respectively, for Ni/Au contacts. The reverse recovery times ranged from 31.2 to 33.5 ns for pure Schottky and heterojunction rectifiers. Switching energy losses for the SBD with W contacts were ∼20% of those for HJDs. The reverse breakdown voltages ranged from 600 V for SBDs to 2400 V for HJDs. These are the lowest reported turn-on voltage values for 600/1200 V-class Ga2O3 rectifiers that extend the range of applications of these devices down to the voltages of interest for electric vehicle charging applications.
研究人员利用低功函数（4.5 eV）钨（W）作为整流触点，在 W/Ga2O3 肖特基整流器和 NiO/Ga2O3 异质结整流器中获得低导通电压。这些器件的相对面积和直径比例各不相同，涵盖了从纯肖特基势垒二极管（SBD）到纯异质结二极管（HJD）的各种配置。纯肖特基整流器 W 触点的开启电压为 0.22 V，纯 HJD 为 1.50 V，而镍/金触点的开启电压分别为 0.66 V 和 1.77 V。纯肖特基和异质结整流器的反向恢复时间为 31.2 至 33.5 ns。带 W 触点的 SBD 的开关能量损失是 HJD 的 20%。SBD 的反向击穿电压从 600 V 到 HJD 的 2400 V 不等。这是报告的 600/1200 V 级 Ga2O3 整流器的最低导通电压值，将这些器件的应用范围扩展到了电动汽车充电应用所需的电压。
{"title":"Achievement of low turn-on voltage in Ga2O3 Schottky and heterojunction hybrid rectifiers using W/Au anode contact","authors":"Chao-Ching Chiang, Jian-Sian Li, Hsiao-Hsuan Wan, Fan Ren, Stephen J. Pearton","doi":"10.1063/5.0227210","DOIUrl":"https://doi.org/10.1063/5.0227210","url":null,"abstract":"The use of the low work function (4.5 eV) tungsten (W) as a rectifying contact was studied to obtain low on-voltages in W/Ga2O3 Schottky rectifiers and NiO/Ga2O3 heterojunction rectifiers that were simultaneously fabricated on a single wafer. The devices were produced with varying proportions of relative areas and diameters, encompassing a spectrum from pure Schottky Barrier Diode (SBD) to pure Heterojunction Diode (HJD) configurations. The turn-on voltages with W contacts ranged from 0.22 V for pure Schottky rectifiers to 1.50 V for pure HJDs, compared to 0.66 and 1.77 V, respectively, for Ni/Au contacts. The reverse recovery times ranged from 31.2 to 33.5 ns for pure Schottky and heterojunction rectifiers. Switching energy losses for the SBD with W contacts were ∼20% of those for HJDs. The reverse breakdown voltages ranged from 600 V for SBDs to 2400 V for HJDs. These are the lowest reported turn-on voltage values for 600/1200 V-class Ga2O3 rectifiers that extend the range of applications of these devices down to the voltages of interest for electric vehicle charging applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"9 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, the higher order electrostatic and solitonic EA energy plasma in auroral plasma has been investigated. The perturbed KdV form has been solved. The modulated soliton speed, energy of the cold beam electrons, and the associated higher fifth order electrostatic field have been mathematically derived. The effect of perturbed beam density as well as beam temperature parameters on the dressed electrostatic and energy properties has been discussed. The auroral plasma results in this work may be important in space applications.
本研究对极光等离子体中的高阶静电和孤子 EA 能量等离子体进行了研究。对扰动 KdV 形式进行了求解。调制孤子的速度、冷束电子的能量以及相关的高五阶静电场都已用数学方法推导出来。还讨论了扰动束密度和束流温度参数对敷装静电和能量特性的影响。这项工作中的极光等离子体结果可能在空间应用中具有重要意义。
{"title":"On the modulated fifth order dressed electron acoustic electrostatic and energy features in auroral plasma","authors":"K. S. Alsadi, E. M. Darwish, E. K. El-Shewy","doi":"10.1063/5.0227184","DOIUrl":"https://doi.org/10.1063/5.0227184","url":null,"abstract":"In this work, the higher order electrostatic and solitonic EA energy plasma in auroral plasma has been investigated. The perturbed KdV form has been solved. The modulated soliton speed, energy of the cold beam electrons, and the associated higher fifth order electrostatic field have been mathematically derived. The effect of perturbed beam density as well as beam temperature parameters on the dressed electrostatic and energy properties has been discussed. The auroral plasma results in this work may be important in space applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"22 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiangjian Wang, Oleg. N. Antzutkin, J. Andreas Larsson
In this work, we investigate the ion pair tetramethylphosphonium cation, [P1,1,1,1]+, and bis(oxalato)borate anion, [BOB]−, as a model system for the study of ionic liquids interacting with both hydroxylated and oxygen terminated α-SiO2 (001) surfaces, using first-principles electronic structure theory. We use a single ionic pair and clusters of ion pairs, in order to have exclusively neutral supercell slab models. We use dispersion-corrected density functional theory (DFT) to ascertain that both the strong physical binding between the ions, dominated by ionic binding, and the weaker physical binding of ions to the different surfaces are correctly described. We have found that the binding of ion pairs is stronger to the hydroxylated α-SiO2 (001) surface compared to the oxygen terminated surface, which is attributed to the formation of H-binding with the oxygen atom(s) of the [BOB]− anion. Through rotation of ionic pair(s), we estimate the surface-ions energy barrier for translational movement and, thus, the strength of H-binding of the ions. At the surface of hydroxylated α-SiO2 (001), we have studied how water molecules form a network of H-binding with the OH groups of the surface and the [BOB]− anion, which offers an explanation for the reduction in the friction of ionic liquids on the inclusion of water. We suggest modeling protocols for simulation of ion pairs on surfaces, which can open up the possibility to use DFT to aid in designing and understanding the physicochemical mechanism of interactions of ionic materials (including ionic liquids) in various technological applications.
在这项研究中，我们利用第一原理电子结构理论研究了离子对四甲基鏻阳离子 [P1,1,1,1]+ 和双(草酸)硼酸阴离子 [BOB]-，并将其作为研究离子液体与羟基化和氧端化 α-SiO2 (001) 表面相互作用的模型系统。我们使用单个离子对和离子对簇，以建立完全中性的超胞板坯模型。我们使用色散校正密度泛函理论（DFT）来确定离子之间以离子结合为主的强物理结合以及离子与不同表面的弱物理结合都得到了正确的描述。我们发现，离子对与羟基化的α-SiO2 (001) 表面相比，与氧终止表面的结合力更强，这归因于[BOB]- 阴离子的氧原子形成了氢键结合。通过离子对的旋转，我们估算出了表面-离子平移运动的能量势垒，从而估算出了离子与 H 结合的强度。在羟基化的α-SiO2 (001) 表面，我们研究了水分子如何与表面的羟基和[BOB]-阴离子形成 H 结合网络，这为离子液体加入水后摩擦力减小提供了解释。我们提出了模拟表面离子对的建模协议，这为利用 DFT 帮助设计和理解各种技术应用中离子材料（包括离子液体）相互作用的物理化学机制提供了可能。
{"title":"Density functional theory study of physisorption of ionic liquid pairs on hydroxylated and oxygen terminated α-SiO2 (001) surfaces","authors":"Xiangjian Wang, Oleg. N. Antzutkin, J. Andreas Larsson","doi":"10.1063/5.0221708","DOIUrl":"https://doi.org/10.1063/5.0221708","url":null,"abstract":"In this work, we investigate the ion pair tetramethylphosphonium cation, [P1,1,1,1]+, and bis(oxalato)borate anion, [BOB]−, as a model system for the study of ionic liquids interacting with both hydroxylated and oxygen terminated α-SiO2 (001) surfaces, using first-principles electronic structure theory. We use a single ionic pair and clusters of ion pairs, in order to have exclusively neutral supercell slab models. We use dispersion-corrected density functional theory (DFT) to ascertain that both the strong physical binding between the ions, dominated by ionic binding, and the weaker physical binding of ions to the different surfaces are correctly described. We have found that the binding of ion pairs is stronger to the hydroxylated α-SiO2 (001) surface compared to the oxygen terminated surface, which is attributed to the formation of H-binding with the oxygen atom(s) of the [BOB]− anion. Through rotation of ionic pair(s), we estimate the surface-ions energy barrier for translational movement and, thus, the strength of H-binding of the ions. At the surface of hydroxylated α-SiO2 (001), we have studied how water molecules form a network of H-binding with the OH groups of the surface and the [BOB]− anion, which offers an explanation for the reduction in the friction of ionic liquids on the inclusion of water. We suggest modeling protocols for simulation of ion pairs on surfaces, which can open up the possibility to use DFT to aid in designing and understanding the physicochemical mechanism of interactions of ionic materials (including ionic liquids) in various technological applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"28 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. R. Seyyedi Birjand, R. Sabbaghzadeh, Maliheh Azadparvar, H. A. Rahnamaye Aliabad
The biophysical properties of metoprolol are investigated by the full potential-linearized augmented plane wave method and molecular docking and molecular dynamic approaches. The exchange–correlation potentials are calculated by the Perdew–Burke–Ernzerhof generalized gradient approximation as implemented in the WIEN2k package. The electronic results show the insulator nature of metoprolol with the indirect bandgap of 3.74 eV between HOMO and LUMO states. In the density of state spectra, the p state of O, C, and N elements confirm the stability of metoprolol. Metoprolol exhibits a metallic behavior in the z direction, while it has a dielectric behavior in the x and y directions. The static refractive indices are obtained 1.49, 1.53, and 1.63 in the x, y, and z directions, respectively. It was found that the maximum reflectivity occurs at the ultraviolet region in the z-direction. The calculated absorption spectra also confirm the other’s experimental results. The obtained results of molecular docking indicate the formation of hydrogen bonds between metoprolol and the beta-2 adrenergic receptors, and molecular dynamics showed a human beta-2 adrenoceptor either in its free state or in complex with a metoprolol molecule. The calculated binding energies of elements by molecular docking and the other biological properties of metoprolol by molecular dynamic are in close agreement with obtained Density Functional Theory (DFT) results for Pharmacia applications.
采用全电位线性化增强平面波法以及分子对接和分子动力学方法研究了美托洛尔的生物物理特性。交换相关电势是通过 WIEN2k 软件包中实现的 Perdew-Burke-Ernzerhof 广义梯度近似法计算得出的。电子结果显示美托洛尔具有绝缘体性质，其 HOMO 和 LUMO 态之间的间接带隙为 3.74 eV。在状态密度谱图中，O、C 和 N 元素的 p 态证实了美托洛尔的稳定性。美托洛尔在 z 方向上表现出金属特性，而在 x 和 y 方向上则表现出介电特性。在 x、y 和 z 方向上的静态折射率分别为 1.49、1.53 和 1.63。研究发现，最大反射率出现在 z 方向的紫外线区域。计算得出的吸收光谱也证实了其他实验结果。分子对接结果表明，美托洛尔与 beta-2 肾上腺素能受体之间形成了氢键，分子动力学结果显示，人 beta-2 肾上腺素受体处于自由状态或与美托洛尔分子复合。通过分子对接计算出的元素结合能以及通过分子动力学计算出的美托洛尔的其他生物特性与在药典应用中获得的密度泛函理论（DFT）结果非常吻合。
{"title":"Comparative bioengineering and optoelectronic properties of metoprolol by DFT, molecular docking, and molecular dynamic approaches","authors":"S. R. Seyyedi Birjand, R. Sabbaghzadeh, Maliheh Azadparvar, H. A. Rahnamaye Aliabad","doi":"10.1063/5.0215159","DOIUrl":"https://doi.org/10.1063/5.0215159","url":null,"abstract":"The biophysical properties of metoprolol are investigated by the full potential-linearized augmented plane wave method and molecular docking and molecular dynamic approaches. The exchange–correlation potentials are calculated by the Perdew–Burke–Ernzerhof generalized gradient approximation as implemented in the WIEN2k package. The electronic results show the insulator nature of metoprolol with the indirect bandgap of 3.74 eV between HOMO and LUMO states. In the density of state spectra, the p state of O, C, and N elements confirm the stability of metoprolol. Metoprolol exhibits a metallic behavior in the z direction, while it has a dielectric behavior in the x and y directions. The static refractive indices are obtained 1.49, 1.53, and 1.63 in the x, y, and z directions, respectively. It was found that the maximum reflectivity occurs at the ultraviolet region in the z-direction. The calculated absorption spectra also confirm the other’s experimental results. The obtained results of molecular docking indicate the formation of hydrogen bonds between metoprolol and the beta-2 adrenergic receptors, and molecular dynamics showed a human beta-2 adrenoceptor either in its free state or in complex with a metoprolol molecule. The calculated binding energies of elements by molecular docking and the other biological properties of metoprolol by molecular dynamic are in close agreement with obtained Density Functional Theory (DFT) results for Pharmacia applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"3 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ning Xu, Wen-Ping Xu, Xin Fu, Rui Su, Wen-Yu Chen, Ying-Nan Shen, Jin Luo
In this study, the dynamic process of a droplet moving with a substrate until blocked by air flow is investigated experimentally and theoretically. A sequence of experiments has been conducted to investigate the impacts of wetting properties, droplet volumes, air flow velocities, and droplet velocities. The substrate is driven by a linear motion motor to ensure the droplet moves at a certain velocity alongside the substrate. The air flow that is vertically injected from the nozzles toward the substrate is known as an impinging jet. After the air flow impacts the substrate, it will blow horizontally. When the direction of air flow is opposite to that of the droplet movement, a force will be exerted on the surface of the droplet. This action incurs the deformation of the droplet and the cessation of its movement, eventually resulting in an equilibrium state. The droplet shape and motion processes are recorded by a high-speed camera. A mathematical model considering the effect of droplet contact angle, droplet size, droplet moving velocity, and air flow velocity is established in the state of equilibrium. Correlation factors are used in the model for the drag coefficient and air average velocity acting on the droplet. It is found that the air flow rate required to stop the motion of the droplet increases with the droplet moving velocity and the droplet size but reduces with the increase in the static contact angle. The mathematical model, when equipped with suitable correlation factors, exhibits good agreement with experimental data and could potentially be utilized as a predictor of critical velocity for the cessation of the droplet motion.
{"title":"Experimental and theoretical study on the ceasing motion of a droplet manipulated by air-blowing nozzle","authors":"Ning Xu, Wen-Ping Xu, Xin Fu, Rui Su, Wen-Yu Chen, Ying-Nan Shen, Jin Luo","doi":"10.1063/5.0208630","DOIUrl":"https://doi.org/10.1063/5.0208630","url":null,"abstract":"In this study, the dynamic process of a droplet moving with a substrate until blocked by air flow is investigated experimentally and theoretically. A sequence of experiments has been conducted to investigate the impacts of wetting properties, droplet volumes, air flow velocities, and droplet velocities. The substrate is driven by a linear motion motor to ensure the droplet moves at a certain velocity alongside the substrate. The air flow that is vertically injected from the nozzles toward the substrate is known as an impinging jet. After the air flow impacts the substrate, it will blow horizontally. When the direction of air flow is opposite to that of the droplet movement, a force will be exerted on the surface of the droplet. This action incurs the deformation of the droplet and the cessation of its movement, eventually resulting in an equilibrium state. The droplet shape and motion processes are recorded by a high-speed camera. A mathematical model considering the effect of droplet contact angle, droplet size, droplet moving velocity, and air flow velocity is established in the state of equilibrium. Correlation factors are used in the model for the drag coefficient and air average velocity acting on the droplet. It is found that the air flow rate required to stop the motion of the droplet increases with the droplet moving velocity and the droplet size but reduces with the increase in the static contact angle. The mathematical model, when equipped with suitable correlation factors, exhibits good agreement with experimental data and could potentially be utilized as a predictor of critical velocity for the cessation of the droplet motion.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"100 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tongzhao Zhang, Zhiqiang Liu, Yongsheng He, Hongguang Ji, Yichao Zhao, Zhaoyang Song
The acoustic emission (AE) characteristic signal can reveal the mechanical properties of rock materials and the development characteristics of internal microcracks. Rocks with different mineral development characteristics produce different AE signals during fracture. This study selected variable metagabbros with varying feldspathic development for AE tests under splitting load. The results demonstrated that the characteristics of AE ringing counts during the Brazilian fracture of metagabbro were closely correlated with the content of felsic minerals. The cumulative AE ringing count of metagabbros with feldspar nondevelopment exceeded 250 000, while those of metagabbros with feldspar development did not reach 200 000. As the feldspathic mineral content increases, the AE ringing counts of metagabbro exhibit an increasing trend in the high-energy (1e6–+∞ aJ) and high-amplitude (90–100 dB) intervals. With the development of feldspar minerals, the fracture mode of metagabbro gradually changed from shear failure to tensile failure. The higher the development of felsic minerals, the higher the stress level corresponding to the maximum fractal dimension, the greater the energy released by rock failure, and the more severe the damage. This study is of great significance for revealing the mechanism of rock rupture.
{"title":"Research on acoustic emission characteristics of metagabbros with different felsic development under splitting load","authors":"Tongzhao Zhang, Zhiqiang Liu, Yongsheng He, Hongguang Ji, Yichao Zhao, Zhaoyang Song","doi":"10.1063/5.0226321","DOIUrl":"https://doi.org/10.1063/5.0226321","url":null,"abstract":"The acoustic emission (AE) characteristic signal can reveal the mechanical properties of rock materials and the development characteristics of internal microcracks. Rocks with different mineral development characteristics produce different AE signals during fracture. This study selected variable metagabbros with varying feldspathic development for AE tests under splitting load. The results demonstrated that the characteristics of AE ringing counts during the Brazilian fracture of metagabbro were closely correlated with the content of felsic minerals. The cumulative AE ringing count of metagabbros with feldspar nondevelopment exceeded 250 000, while those of metagabbros with feldspar development did not reach 200 000. As the feldspathic mineral content increases, the AE ringing counts of metagabbro exhibit an increasing trend in the high-energy (1e6–+∞ aJ) and high-amplitude (90–100 dB) intervals. With the development of feldspar minerals, the fracture mode of metagabbro gradually changed from shear failure to tensile failure. The higher the development of felsic minerals, the higher the stress level corresponding to the maximum fractal dimension, the greater the energy released by rock failure, and the more severe the damage. This study is of great significance for revealing the mechanism of rock rupture.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"6 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurate estimation of the State of Health (SOH) of batteries is important for intelligent battery management in energy storage systems. To solve the problems of poor quality of data features as well as the difficulty of model parameter adjustment, this study proposes a method for estimating the SOH of lithium batteries based on denoising battery health features and an improved Long Short-Term Memory (LSTM) neural network. First, in this study, three health features related to SOH decrease were selected from the battery charge/discharge data, and the singular value decomposition technique was applied to the noise reduction of the features to improve their correlation with the SOH. Then, the whale optimization algorithm is improved using cubic chaotic mapping to enhance its global optimization-seeking capability. Then, the Improved Whale Optimization Algorithm (IWOA) is used to optimize the model parameters of LSTM, and the IWOA-LSTM model is applied to the battery SOH estimation. Finally, the model proposed in this research is validated against the Center for Advanced Life Cycle Engineering (CALCE) battery dataset. The experimental results show that the prediction error of battery SOH by the method proposed in this study is less than 0.96%, and the prediction error is reduced by 49.42% compared to its baseline model. The method presented in the article achieves accurate estimation of the SOH, providing a reference for practical engineering applications.
{"title":"Energy storage battery state of health estimation based on singular value decomposition for noise reduction and improved LSTM neural network","authors":"Tao Chen, Shaohong Zheng, Linjia Xie, Xiaofei Sui, Fang Guo, Wencan Zhang","doi":"10.1063/5.0217697","DOIUrl":"https://doi.org/10.1063/5.0217697","url":null,"abstract":"Accurate estimation of the State of Health (SOH) of batteries is important for intelligent battery management in energy storage systems. To solve the problems of poor quality of data features as well as the difficulty of model parameter adjustment, this study proposes a method for estimating the SOH of lithium batteries based on denoising battery health features and an improved Long Short-Term Memory (LSTM) neural network. First, in this study, three health features related to SOH decrease were selected from the battery charge/discharge data, and the singular value decomposition technique was applied to the noise reduction of the features to improve their correlation with the SOH. Then, the whale optimization algorithm is improved using cubic chaotic mapping to enhance its global optimization-seeking capability. Then, the Improved Whale Optimization Algorithm (IWOA) is used to optimize the model parameters of LSTM, and the IWOA-LSTM model is applied to the battery SOH estimation. Finally, the model proposed in this research is validated against the Center for Advanced Life Cycle Engineering (CALCE) battery dataset. The experimental results show that the prediction error of battery SOH by the method proposed in this study is less than 0.96%, and the prediction error is reduced by 49.42% compared to its baseline model. The method presented in the article achieves accurate estimation of the SOH, providing a reference for practical engineering applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"158 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In conditions of low visibility, the scattering effect of atmospheric particles can result in images captured by cameras exhibiting a number of problems, including reduced contrast, color distortion, and blurred details. These issues can have a significant impact on the clarity and recognition of the images. In response to these issues, this study combines atmospheric scattering models with wavelet transform, introduces non-blind deconvolution algorithms and, finally, designs a special gamma correction function to ultimately develop a new foggy image restoration model. The relevant outcomes showed that when the dehazing model processed most image samples, its edge preservation was mainly concentrated in a relatively high range, namely [0.80, 0.96]. From the perspective of the structural similarity index, the discrete wavelet transform achieved the highest value of 0.8264. In addition, the peak signal-to-noise ratio of the improved gamma correction function was 18.346. The proposed algorithm for restoring foggy images has the advantages of high clarity, strong color restoration ability, and fast restoration speed, providing more reliable and efficient image data support for applications in related fields.
{"title":"Restoration of misty images based on wavelet transform and atmospheric scattering model","authors":"Pengcheng Liu","doi":"10.1063/5.0219235","DOIUrl":"https://doi.org/10.1063/5.0219235","url":null,"abstract":"In conditions of low visibility, the scattering effect of atmospheric particles can result in images captured by cameras exhibiting a number of problems, including reduced contrast, color distortion, and blurred details. These issues can have a significant impact on the clarity and recognition of the images. In response to these issues, this study combines atmospheric scattering models with wavelet transform, introduces non-blind deconvolution algorithms and, finally, designs a special gamma correction function to ultimately develop a new foggy image restoration model. The relevant outcomes showed that when the dehazing model processed most image samples, its edge preservation was mainly concentrated in a relatively high range, namely [0.80, 0.96]. From the perspective of the structural similarity index, the discrete wavelet transform achieved the highest value of 0.8264. In addition, the peak signal-to-noise ratio of the improved gamma correction function was 18.346. The proposed algorithm for restoring foggy images has the advantages of high clarity, strong color restoration ability, and fast restoration speed, providing more reliable and efficient image data support for applications in related fields.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"7 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：