bluuebunny/crossref_metadata_2025_split huggingface dataset:
A hybrid FCN-BiGRU with transfer learning for low-velocity impact identification on aircraft structure
Authors: Huang Chenhui , Liao Weilin , Sun Hu , Wang Yishou , Qing Xinlin 
Published: March 2023

Abstract
In the work process of an aircraft, its external structure frequently encounters some low-velocity impact events, resulting in some barely visible impact damages inside the structure. Therefore, impact localization and reconstruction are critical for the structure’s health monitoring and reliability analysis. However, traditional inversion methods usually perform poorly in identifying random impact loads due to a series of problems. Inspired by the superior model properties of deep learning algorithms, a novel feature learning-based technique for impact load reconstruction and localization is presented. The proposed method consists of two parts, the first of which is utilized to localize the impact loads and is referred to as one-dimensional full convolution network. The other part aims at reconstructing the impact load and is called attention mechanism-full convolutional network-bidirectional gating recurrent unit-multilayer perceptron. Moreover, a transfer learning technique is introduced to optimize the model structure and process in light of the suggested innovative network model. The experimental piece of this research was an aircraft cutting segment whose structural surface was equipped with a number of piezoelectric sensors. These sensors received impact response signals with differences in amplitude from hammer strikes at various positions. In the work, the process of locating first and then reconstructing the impact load history was followed. And the influence of implementing the transfer learning mechanism on the performance of the impact load history reconstruction model was investigated as well. Three experiments and repeated cross-validation verified the efficacy of the proposed method. The findings indicated that the proposed technique could accurately and quickly detect impact loads at various locations. Simultaneously, it also allowed a perfect reconstruction of the impact loads of different impact energies.
CrackDiffusion: crack inpainting with denoising diffusion models and crack segmentation perceptual score
Authors: Chen Lizhou , Zhou Luoyu , Li Lei , Luo Mingzhang 
Published: March 2023

Abstract
Cracks commonly occur in engineering structures. Imaging method is one of the most effective detection method for crack. However, crack information captured by the imaging sensors is often interfered by noise and the other environmental factors. In this paper, we propose a crack inpainting method that can automatically repair the missing crack information. The inpainting method consists of a denoising diffusion model and a segmentation guidance model. Taking advantages of denoising diffusion model’s stability and segmentation guidance model’s accuracy, we can achieve coherent inpainting patches as well as accurate crack traces. Furthermore, we propose a fine crack metric—crack segmentation perceptual score to guide high quality crack generation. Experimental results show that our method achieves both high quality and precise crack inpainting results, which is very beneficial to the crack detection and evaluation in structural health monitoring.
Quantum generative adversarial imitation learning
Authors: Xiao Tailong , Huang Jingzheng , Li Hongjing , Fan Jianping , Zeng Guihua 
Published: March 2023

Abstract
Investigating quantum advantage in the NISQ era is a challenging problem whereas quantum machine learning becomes the most promising application that can be resorted to. However, no proposal has been investigated for arguably challenging inverse reinforcement learning to demonstrate the potential advantage. In this work, we propose a hybrid quantum–classical inverse reinforcement learning algorithm based on the variational quantum circuit with the generative adversarial framework. We find an important connection between the quantum gradient anomaly and the performance degradation, which suggest a gradient clipping strategy to stabilize the training process. In light of the algorithm, we study three classic control problems and the Hamiltonian parameter estimation in quantum sensing with shallow quantum circuits. The numerical results showcase that the control-enhanced quantum sensor can saturate quantum Cramér-Rao bound only with a single variational layer, empirically demonstrating a parameter complexity advantage over the classical learning control. The proposed generative adversarial reinforcement learning algorithm achieves state-of-the-art performance in classical and quantum sensor control in terms of required number of parameters.
Spatiotemporally controllable honeycomb superlattice plasma photonic crystals in dielectric barrier discharge
Authors: Fan Weili , Hou Xiaohan , Jia Mengmeng , Tian Miao , He Yafeng , Liu Fucheng 
Published: March 2023

Abstract
We present the experimental realization of tunable honeycomb superlattice plasma photonic crystals (PPCs) in dielectric barrier discharge by utilizing mesh-liquid electrodes. Fast reconfiguration among the simple honeycomb lattice, honeycomb superlattice, and honeycomb-snowflake superlattice is achieved. A dynamic control on the sizes of center scattering elements in the honeycomb superlattice has been realized. A phenomenological activator-inhibitor reaction diffusion model is established to demonstrate the formation and reconstruction of the honeycomb superlattice. The simulations reproduce well the experimental observations. The photonic band diagrams of different honeycomb PPCs are studied by using the finite element method. The addition of large center elements in honeycomb superlattice yields remarkable omnidirectional band gaps that are about 2.5 times larger than in the simple honeycomb lattice. We propose an effective scheme to fabricate spatiotemporally controllable honeycomb lattices that enable great improvement in band gap size and dynamic control of microwave radiations for wide applications.
From a wide band gap to the superconducting proximity effect: Fe on Pb(111)
Authors: Omidian M , Brand J , Néel N , Crampin S , Kröger J 
Published: March 2023

Abstract
Epitaxially grown Fe nanostructures on Pb(111) were studied by low-temperature scanning tunneling microscopy and spectroscopy. The deposited Fe assemblies are classified into two groups according to their electronic behavior close to the Fermi energy. One group exhibits a wide energy gap of 0.7 eV that is independent of the temperature ranging from 5 K to room temperature. These Fe islands indicate the absence of the superconductivity proximity effect in their interior. The other group shows a metallic behavior at the Fermi level. The substrate superconducting phase locally enters into these islands, which is evidenced by a sharp resonance at the Fermi energy presumably signaling Andreev reflection at the magnet–superconductor interface.
Bulk electronic structure of Mn2NiGa using hard x-ray photoelectron spectroscopy and density functional theory
Authors: Sadhukhan Pampa , Sarkar Shuvam , D’Souza Sunil Wilfred , Gloskovskii Andrei , Roy Barman Sudipta 
Published: March 2023

Abstract
Mn2NiGa is a potential magnetic shape memory alloy with austenite to the martensite phase transition. Here, we have investigated the bulk electronic structure of Mn2NiGa in the austenite and martensite phases studying its valence band using hard x-ray photoelectron spectroscopy (HAXPES). In the austenite phase, we observe a wide (≈10 eV) valence band (VB) spectrum with several prominent features. In order to explain the HAXPES VB spectra, we have compared our experimental VB spectra with the theoretical VB calculated using the partial density of states from our existing density functional theory (DFT) calculations. The shape of the experimental VB and energy positions of all features are in excellent agreement with the calculated VB and we find that the former is dominated by Ni 3d as well as 4s states of Mn, Ni, and Ga. An important observation is that experimental VB combined with the DFT-based VB calculation establishes the prevalence of the anti-site disorder in Mn2NiGa. Compared to the austenite phase, in the martensite phase, the VB shows a marginal decrease in the density of states around −0.5 eV below the Fermi level (E

F
), and the main peak is slightly shifted towards E

F
. These experimental observations have been explained by considering the tetragonally distorted structure with the anti-site disorder in the martensite phase.
An iterative method for simultaneous reduction on beam-hardening and scatter artifacts in x-ray CT
Authors: Xia Dimeng , Zhao Shusen , Zhang Huitao , Zhu Yining , Zhao Xing , Zhang Peng 
Published: March 2023

AbstractBeam-hardening and scatter are two significant factors leading to contrast reduction and gray value inaccuracy in CT images. The cupping artifacts and obscure boundaries in reconstructed images are also caused mainly by both beam-hardening and scattering. It is difficult to get high-quality CT images with only one of them to make correction. In this paper, we proposed an x-ray CT polychromatic attenuation model with scatter effect, and an iterative method for simultaneous reduction on beam-hardening and scatter artifacts. In this model, the measurements of the detector comprise two parts: an attenuation term and a scatter term. The former is defined by an exponential rational fraction to fit the traditional attenuation process, and the latter is defined by a convolutional scatter intensity. The coefficients of the rational fraction in the attenuation term and the scatter term kernel are all calculated from a calibration phantom which is scanned to get corresponding equations. Based on the polychromatic attenuation model, we proposed an iterative artifacts reduction method combining deconvolution technique with linearized back-projection (iDLB method). This method makes the nonlinear polychromatic attenuation model become easily solvable by linearizing transformation, which simplifies the residuals allocation process. Experiments of both numerical simulation and practical data show the iDLB method has the ability to reduce beam-hardening and scatter artifacts simultaneously, improve the contrast of CT images, and it is highly parallelized for lower computational cost.
Extreme heatwave over Eastern China in summer 2022: the role of three oceans and local soil moisture feedback
Authors: Jiang Jilan , Liu Yimin , Mao Jiangyu , Wu Guoxiong 
Published: March 2023

Abstract
Eastern China experienced persistent regional extreme heatwaves in the summer of 2022, with disparate spatial features and formation mechanisms in different months. We quantitatively assessed the relative contributions of three oceans, i.e. tropical Indian Ocean and Pacific and North Atlantic, and the local soil moisture–temperature feedback using linear regression. The results showed that the monthly mean atmospheric circulation anomalies failed to explain the extreme heatwave in June 2022. The combined contribution of the tropical Indo-Pacific and North Atlantic sea surface temperature anomalies (SSTAs), together with the local soil moisture–temperature feedback, explaining approximately 10% of the temperature anomalies. In July, the tropical Indo-Pacific SSTAs promoted anomalous atmospheric circulation and extreme heat via meridional circulation originating in the Maritime Continent, accounting for approximately 10% of the temperature anomalies, with North Atlantic SSTAs contributing the same percentage by a mid-latitude steady Rossby wave. Local soil moisture–temperature feedback accounted for 42% of the anomalies. The tropical Indo-Pacific SSTAs produced a strong western North Pacific anticyclone in August, but their direct contribution to the temperature anomalies was negligible. The North Atlantic SSTAs contributed 9% of the total via the mid-latitude steady Rossby wave. Local soil moisture–temperature feedback contributed 66%, suggesting that the July heatwave and drought exerted a significant impact on the subsequent August extreme heatwave. Global warming has greatly facilitated extreme heatwaves, accounting for about 30%–40% of these events in summer 2022. These results also suggest that the climatic effects of tropical Indo-Pacific and North Atlantic SSTAs on Eastern China are evident in the month-to-month variation in summer. Our results thus contribute to the understanding and prediction of extreme heatwaves in Eastern China.
Opportunities and prospects for the use of solar energy for refrigeration of public buildings
Authors: Izzatillaev J , Alimova L , Usmonov N , Alijanov D 
Published: March 2023

Abstract
This paper describes the calculation of evaporative-radiant cooling of recycled water in summer air-conditioning systems. A differential equation for the heat balance of water flowing down an inclined plane is derived. As one possible way of increasing the efficiency of air conditioning systems based on cooling water by adiabatic evaporation in the air flow the use of night-time evaporative cooling of the water, followed by daytime cooling in insulated storage tanks. The temperature of the water chilled in this way is 3-4 °C lower than the temperature of the water chilled during the day, and the final water temperature is close to the saturation temperature of the outside air. The equations for calculation of mass transfer coefficients, radiation and heat transfer coefficient of an insulated bottom of an evaporative-radiant water-cooling unit are given. Based on the Mathcad program and the result of the calculation, the dependence of the final water temperature on the initial water temperature is obtained. As a result of the calculation, the specific heat capacity of the evaporative radiant water-cooling unit for the production of free cooling is determined.
Application of ozone electrodispersion technology for disinfection of water
Authors: Babayev A , Tasheva U , Allenova I , Sanbetova A T 
Published: March 2023

Abstract
This article provides definitions of the positive and negative effects of the use of chlorine and ozone in water disinfection and presents the methodology and results of experimental studies of the parameters of water treatment with ozone, the electrodispersion method, as well as the electrode system “potential plane with corona needles - grounded plane”. The parameters of water treatment modes were determined by the method of three variants of aerosol charge, negative, positive and bipolar. The parameters of water treatment with ozone determined on the basis of these studies were verified on the basis of experimental studies of the process of ozone effects on aerosol particles in the contact chamber. The methodology and analysis of the results of these studies are given. Based on these studies, the best ratios of the parameters of water flow, air velocity and electrical voltage were determined. The best disinfection result was determined by the charge polarities of the water aerosol.
Corona discharge ozonizers with vacuum coatings and their use for processing agricultural products
Authors: Parpiyev M P , Simonov A A , Kamardin A I , Kh Abdurakhmanov O 
Published: March 2023

Abstract
At present the majority of ozonizers in the world are manufactured on the basis of a barrier discharge. But the special ceramic electrodes used for such ozonizers are highly sensitive to humidity and pollution of the air supplied to the device. Typically, these devices use cartridges to filter and dehumidify the air. In this research, corona discharge ozone generators were used due to sufficient energy efficiency and ease of implementation of this method of ozone synthesis from oxygen-containing gases. The results showed that that coatings with a thickness of up to 3-5 μm made it possible to create a layer on the electrode surface that protects against oxidation or has a conductive oxide that maintains the operability of the point electrode. Furthermore, In the system of electrodes of the point-plane type, a voltage of positive polarity was applied to the point electrode. The initial voltage applied to the discharge gap was 14–15 kV. As the surface properties of the samples changed, the voltage had to be reduced to avoid spark breakdown.
The influence of the impact of electrical impulses on the juice outputting of the pulp
Authors: Eshpulatov N , Khalmuradov T , Rakhimov F , Abdurayimov S , Khurramov A , Mullajonov I , Vorisova R 
Published: March 2023

Abstract
In this article was applied a comprehensive research method which made it possible to quite fully investigate the mechanism of the effect of electrical impulses on the protoplasm of cells and determine the optimal parameters of such effect on plant raw materials, ensuring high efficiency of their use to increase the juice yield. The complex research method made it possible to obtain the necessary data for the implementation of the electrical method for intensifying the process of extracting juice from plant materials. Due to the fact that the issues related to the use of electrical impulses for the processing of plant materials have been little studied and there is no sufficiently clear understanding of the mechanism of such an effect on living cells, we made an attempt to investigate the mechanism of this process. A technique has been developed for studying the dynamics of the action of electric current on plant tissue cells. We expressed the yield of juice from raw materials as a percentage of the weight of the pulp, which was processed and pressed. Thus, a comparison of the results of individual experiments showed an absolute increase in juice yield as a percentage.
Development and testing of a laboratory model of a two-turbine small hydroelectric power plant
Authors: Davirov A , Kodirov D , Tukhtaeva R , Ibragimov I , Urokova N 
Published: March 2023

Abstract
This article considers the main methods of regulating water consumption and power of micro hydroelectric power plants. New technical solutions for screw jet turbines adapted to low pressures and water flow rates are proposed. The Archimede’s screw turbine is a cost-effective and environmentally friendly microhydropower technology that operates at high efficiency at low pressure and medium flow rates. In this case, the change in power depends on the following parameters: the number of blades, water flow, the angle of inclination of the blades and the height of the pressure. Preliminary calculations carried out by the authors show that the power of a microhydroelectric power station depends on individual factors of the area. With an increase in the speed of the water flow, the speed of the water wheel also increases, and in turn, the electric power of the microhydroelectric power station increases.
Flow stabilization and pulsation in external channels in fuel engines
Authors: Musabekov Z , Khakimov J , Yangiboev A , Tairova N , Usmonov J , Petruchenko A 
Published: March 2023

Abstract
A turbocharger installed in the gas exchange system of a reciprocating internal combustion engine has a significant impact on the gas-dynamic and thermophysical characteristics of the exhaust process. When installing a turbocharger in a discharge system, there is the possibility of mitigating local pulsations of flow rate and pressure in the discharge pipe. The use of such an exhaust system increases the output capacity of the piston fuel engines outlet pipeline by approximately 20%, which also has a positive effect on the performance of individual systems and units such as the turbocompressor and exhaust manifold and reduces the temperature stress of the engine exhaust system and turbocompressor turbine elements.
Study on determination of an asynchronous motor’s reactive power by the current-to-voltage converter
Authors: Karimjonov D D , Siddikov I X , Azamov S S , Uzakov R 
Published: March 2023

Abstract
This article presents a method for determining the primary currents, non-sinusoidal and asymmetrical currents flowing through the stator windings of an asynchronous motor based on the signal in the form of the output voltage from the current converter loops placed in each phase between the poles of the asynchronous motor stator and in the arrangement of the stator windings. Differences and characteristics of output signals are researched based on independent, series and opposite (bifilar) connection schemes of asynchronous motor current converter loops of measuring coil. In order to determine the value of the currents generated in each phase of the asynchronous motor stator windings, the output signals of the current converter with independent loop and loops connected in series were mutually analyzed. Measuring non-sinusoidal and asymmetrical currents, according to the opposite (bifilar) connection scheme, the loops of measuring coils are placed in the inter-pole grooves of each phase of the stator in the order corresponding to the three-phase stator windings, the current converter measuring coils each consists of two loops, bifilarly connected to each other. The end of loops of the measuring coils has two exits. Diodes and phase meter-regulators are placed on the first outputs of the loops, and they are oppositely connected to the microprocessor unit for measuring and controlling the asymmetry. The second outputs of the loops are connected directly opposite to the microprocessor unit for measuring and controlling non-sinusoidal currents. This type of current converter is important for determining the non-sinusoidal and asymmetrical currents generated in asynchronous motors, it increases the functional capabilities and accuracy of the current converter, and based on the determined results, it simplifies theoretical calculations, and at the same time, the dynamic and it will be possible to determine the static characteristics through theoretical differential equations. As a result of the research, practical and theoretical results were compared.
Study on application of electrohydraulic effect for disinfection and increase of water nutrient content for plants
Authors: Turdiboyev A , Aytbaev N , Mamutov M , Tursunov A , Toshev T , Kurbonov N 
Published: March 2023

Abstract
This article describes the application of electrohydraulic effect to decontaminate wastewater and increase nutrient content in water for agricultural crops. It is characterized by the formation of chemical processes in water and electrohydraulic effect carried out using ultrasound and ultraviolet radiation. The nutrient content in water has increased from 1.1 mg/l to 2.23 mg/l, i.e. it has gone up by 102.7% after the preliminary water treatment by means of the electrohydraulic effect, while neutralization of coliform bacteria in the treated water has decreased from 3474 (RLU) to 610 (RLU), i.e. it has dropped to 82.55 over control. The increase of nutrient chemicals in water and coliform bacteria neutralization (Escherichia coli) depend on the treatment time, discharge voltage, capacitor capacity, discharge interval and the number of pulses if treated with electrohydraulic effect conducted by means of ultrasound and ultraviolet radiation causing a chemical reaction of electrohydraulic shock in water. The discharge voltage for increase is 9-15 kV, disinfection time - 100-120 minutes depending on the voltage of treatment. It is advisable to have the capacitor capacity of 0.8 μF and discharge interval of 10-12 mm.
Studying on thermal processes during the motion of combustion products in the gas chimneys of the heat power plant
Authors: Anarbaev A , Kodirov D , Khushiev S , Izzatillaev J , Isakov A , Berdiyorov T , Shukuraliev A , Normuminov J 
Published: March 2023

Abstract
This article discusses the new in Uzbekistan heat recovery technology is leaving the flue gas from boilers. This is achieved by condensation of water vapor therein. An analysis of the advantages and disadvantages of contact heat recovery and surface types. The analysis of the heat transfer coefficients in the condensing heat exchanger surface. The temperature regimes which provide point of the flue gas dew point. The limited stresses in the chimney of the boiler unit are calculated using condensing heat utilizers of the exhaust gas for stations of Uzbekistan.