bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Fine-Grain Carbon Materials in the Process of Smelting Lead from Battery Paste
Authors: Siwiec Grzegorz , Matula Tomasz , Kokowska-Pawłowska Magdalena
Published: November 2024

The recycling of used lead–acid batteries is currently the main source of lead in the world. More than 50% of the weight of a used lead–acid battery is battery paste, in which lead occurs in compounds with oxygen and sulfur. In pyrometallurgical processes of battery paste, coke or coke breeze is used as a traditional additive acting as a fuel/reducer. Due to the constantly high prices of these materials, research is being carried out to find alternative (equally efficient but cheaper) carbon-bearing materials. Those materials can be technological replacements for coke or coke breeze in pyrometallurgical processes. The aim of the presented work was to check the possibility of using fine-grained carbon-bearing materials, in the form of anthracite dust and coal flotation concentrate, for battery paste processing, as replacements for traditionally used coke and coke breeze. As part of the presented work, the following tests were carried out: thermogravimetric tests using battery paste, processes of smelting battery paste in a pit furnace, and processes of smelting battery paste in a rotary furnace. The research results indicate that fine-grained carbon-bearing materials, in the form of anthracite dust and coal flotation concentrate, can be successfully used as a replacement for traditionally used fuels/reducers.
Big Data Analysis, Design, Effect Fabrication, and Properties Analysis of SiO2/Cr/SiO2 Colored Solar Selective Absorbers with High PTCE and Chromaticity for Building Applications
Authors: Lai Fu-Der , Lai Yen-Ting , Chen Chang-Song
Published: November 2024

In today’s era of rapid computing, advanced big data analytics enables precise results and efficient trend analysis. By leveraging these tools, the influence of various film thicknesses of Colored Solar Selective Absorbers (CSSAs) on solar absorption efficiency (αs) and chromaticity was investigated. A clear and visually informative Chromaticity Coordinate Distribution (CCD) versus αs diagram was constructed within the CIE xy chromaticity diagram, establishing a correlation between chromaticity and αs. Photo-Thermal Conversion Efficiency (PTCE) ≈ αs − 2% when αs ≥ 90%. Subsequently, utilizing colored CCD-αs diagrams, seven SiO2/Cr/SiO2 CSSAs, each with unique colors and αs, were designed, fabricated, and subjected to an analysis of their optical and material properties. We explored the influence of oxygen atom infiltration into the CSSA, leading to the oxidation of the Cr layer and consequent alterations in CSSA properties. Additionally, this study delved into analyzing the effect of substrate surface roughness on the oxidation resistance, αs, color, and corrosion resistance of CSSAs.
Thin and Flexible PANI/PMMA/CNF Forest Films Produced via a Two-Step Floating Catalyst Chemical Vapor Deposition
Authors: Papadopoulou Foteini-Maria , Soulis Spyros , Trompeta Aikaterini-Flora A. , Charitidis Costas A.
Published: November 2024

In this paper, we explore a straightforward two-step method to produce high-purity, vertically aligned multi-walled carbon nanofibres (MWCNFs) via chemical vapor deposition (CVD). Two distinct solutions are utilized for this CVD method: a catalytic solution consisting of ferrocene and acetonitrile (ACN) and a carbon source solution with camphor and ACN. The vapors of the catalytic solution inserted in the reaction chamber through external boiling result in a floating catalyst CVD approach that produces vertically aligned CNFs in a consistent manner. CNFs are grown in a conventional CVD horizontal reactor at 850 °C under atmospheric pressure and characterized by Raman spectroscopy, scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Coating the MWCNTs with polymethyl methacrylate (PMMA) while still on the Si substrate retains the structure and results in a flexible, conductive thin film suitable for flexible electrodes. The film is 62 μm thick and stable in aqueous solutions, capable of withstanding further processing, such as electropolymerization with polyaniline, to be used for energy storage applications.
A Novel Tensile Fracture Location of Friction Plug Welding (FPW) Joints
Authors: Wang Yu-Shu , Lv Xue-Qi , Xia Chun-Ming , Li Xiong-Ying , Yang Jie , Li Chong-Gui
Published: November 2024

The fracture position of a friction plug welding (FPW) joint is typically located at or near the thermo-mechanically affected zone (TMAZ). Here, we found that microcracks in all FPW specimens initiate at the deformed plug center (DPC) zone and then propagate through the plug center along 45° shear surfaces, because the lowest hardness occurs at the DPC zone rather than the TMAZ or other zones, and the DPC zone presents a tilt fiber-like microstructure. Such a tilt microstructure stimulates formations and deformations of microvoids and propagation of microcracks along 45° shear surfaces. The ultimate tensile strength (237.7 MPa) and yield strength (220.8 MPa) of the FPW joint reach 78.8% and 85.7% of the base metal, respectively. These results indicate that 6061-T6 aluminum alloy can be effectively joined by the FPW technique.
Hydrogen Embrittlement Sensitivity of X70 Welded Pipe Under a High-Pressure Pure Hydrogen Environment
Authors: Shuai Kangxin , Liu Haixiao , Li Ming , Yin Shubiao , Li Ba , Wang Bing , Liu Qingyou , Jia Shujun
Published: November 2024

With the rapid development of hydrogen pipelines, their safety issues have become increasingly prominent. In order to evaluate the properties of pipeline materials under a high-pressure hydrogen environment, this study investigates the hydrogen embrittlement sensitivity of X70 welded pipe in a 10 MPa high-pressure hydrogen environment, using slow strain rate testing (SSRT) and low-cycle fatigue (LCF) analysis. The microstructure, slow tensile and fatigue fracture morphology of base metal (BM) and weld metal (WM) were characterized and analyzed by means of ultra-depth microscope, scanning electron microscope (SEM), electron backscattering diffraction (EBSD), and transmission electron microscope (TEM). Results indicate that while the high-pressure hydrogen environment has minimal impact on ultimate tensile strength (UTS) for both BM and WM, it significantly decreases reduction of area (RA) and elongation (EL), with RA reduction in WM exceeding that in BM. Under the nitrogen environment, the slow tensile fracture of X70 pipeline steel BM and WM is a typical ductile fracture, while under the high-pressure hydrogen environment, the unevenness of the slow tensile fracture increased, and a large number of microcracks appeared on the fracture surface and edges, with the fracture mode changing to ductile fracture + quasi-cleavage fracture. In addition, the high-pressure hydrogen environment reduces the fatigue life of the BM and WM of X70 pipeline steel, and the fatigue life of the WM decreases more than that of the BM as well. Compared to the nitrogen environment, the fatigue fracture specimens of BM and WM in the hydrogen environment showed quasi-cleavage fracture patterns, and the fracture area in the instantaneous fracture zone (IFZ) was significantly reduced. Compared with the BM of X70 pipeline steel, although the effective grain size of the WM is smaller, WM’s microstructure, with larger Martensite/austenite (M/A) constituents and MnS and Al-rich oxides, contributes to a heightened embrittlement sensitivity. In contrast, the second-phase precipitation of nanosized Nb, V, and Ti composite carbon-nitride in the BM acts as an effective irreversible hydrogen trap, which can significantly reduce the hydrogen embrittlement sensitivity.
Hydrogels and Their Functionalization—Analysis of the Possibility of Their Application in Post-Fire Water Treatment Processes
Authors: Rabajczyk Anna , Gniazdowska Justyna , Stojek Piotr , Czyżewska Katarzyna , Trusek Anna , Labus Karolina
Published: November 2024

Increasingly intense changes in climatic conditions and the use of modified materials are causing fires, the consequences of which are increasingly serious for the environment. On one hand, there is the issue of access to water resources. On the other hand, there is the problem of post-fire wastewater, which often contains a mixture of simple inorganic compounds and complex organic molecules, making the removal of pollutants a difficult task requiring innovative approaches. Among these solutions, hydrogels stand out as a promising class of sorption materials. Depending on their synthesis or functionalization, hydrogels can effectively capture contaminants and facilitate the reduction or removal of specific pollutants. This study explores the functionalization of polymeric materials, specifically hydrogels, using microorganisms or bioactive substances to create materials capable of treating water contaminated with hazardous substances generated during firefighting incidents. The possibility of wastewater capture was also taken into account to retain pretreated water at the place of pollutant generation. The analysis covered the potential, conditions, and limitations of using hydrogels in post-fire operations for the effective management of contaminated waters. It was shown that hydrogels, depending on the modification, have the potential to capture wastewater and purify it from both organic and inorganic substances specific to post-fire wastewater. However, it is not possible for a given hydrogel to meet all desired expectations at the same time. Furthermore, modifications that facilitate the optimal performance of certain functionalities may render the others ineffective.
The Influence of Heat Treatment on the Tensile Creep Life of the TC25 Titanium Alloy
Authors: Tian Ang , Ma Jianglong , Liu Zhiguo , Kong Guangming , Geng Jiacheng , Huang Xinyuan , Li Guanliang
Published: November 2024

High-temperature titanium alloys are significant materials in the aerospace field, and their service life largely depends on creep aging. However, the creep behavior of the TC25 titanium alloy at high temperatures has not been reported. Here, the creep behavior of TC25 before and after heat treatment at 550 °C under different stresses was investigated. It was found that heat treatment significantly enhanced the creep resistance of the TC25 alloy. An increase in creep stress increased the steady-state creep rate and reduced creep life. The smooth αp/βtrans grain boundaries and refined αs improved creep resistance, and the creep mechanism changed from grain boundary sliding to dislocation climbing after heat treatment. This research provides theoretical data support for the application of the TC25 alloy at high temperatures.
Research on Feedforward-Feedback Composite Anti-Disturbance Control of Electro-Hydraulic Proportional System Based on Dead Zone Compensation
Authors: Dai Jianbo , Xu Haozhi , Si Lei , Wei Dong , Gu Jinheng , Chen Hang
Published: November 2024

Considering the complexity and difficulty of obtaining certain parameters in the electro-hydraulic proportional control system, a precise transfer function of the system was derived through parameter identification using experimental data obtained from an Amesim simulation model after establishing a basic mathematical model. This approach reduces the reliance on accurate parameters of individual components. A feedforward-feedback composite controller was designed, and its effectiveness was validated in Simulink using the system’s transfer function. Subsequently, the dead zone range of the proportional valve was determined through experiments, and a dead zone compensation strategy was designed, which reduced the time required for the proportional valve to traverse the dead zone by 89.4%. Based on the dead zone compensation, trajectory tracking experiments were conducted to validate the effectiveness of the feedforward-feedback composite controller. Under fixed disturbances, the trajectory tracking error was reduced by 53.8% compared to feedback control. Under time-varying load disturbances, the trajectory tracking error was reduced by 51.2% compared to feedback control.
Enhanced Fault Detection in Satellite Attitude Control Systems Using LSTM-Based Deep Learning and Redundant Reaction Wheels
Authors: Saraygord Afshari Sajad
Published: November 2024

Reliable fault detection in satellite attitude control systems stands as a critical aspect of ensuring the safety and success of space missions. Central to these systems, reaction wheels (RWs), despite being the most frequently used actuators, present a vulnerability given their susceptibility to faults—a factor with the potential to precipitate catastrophic failures such as total satellite loss. In light of this, we introduce a fault detection methodology grounded in deep learning techniques specifically designed for satellite attitude control systems. Our proposed method utilizes a Long Short-Term Memory (LSTM) model adept at learning temporal patterns inherent to both healthy and faulty system behaviors. Incorporated into our model is a torque allocation algorithm designed to circumvent specific velocities known to induce torque disturbances, a factor known to influence LSTM performance adversely. To bolster the robustness of our fault detection technique, we also incorporated denoising autoencoders within the LSTM framework, thereby enabling the model to identify temporal patterns in healthy and faulty system behavior, even amidst the noise. The method was evaluated using cross-validation on simulated satellite data comprising 1000 time series samples and across different fault scenarios, such as stiction and resonance at varying intensities (90%, 50%, and 30%). The results confirm achieving performance metrics such as Mean Squared Error for accurate fault identification. This research underscores a stride in the evolution of fault detection and control strategies for satellite attitude control systems, holding promise to boost the reliability and efficiency of future space missions.
Enhanced Carbon Price Forecasting Using Extended Sliding Window Decomposition with LSTM and SVR
Authors: Cai Xiangjun , Li Dagang , Feng Li
Published: November 2024

Accurately forecasting carbon prices plays a vital role in shaping environmental policies, guiding investment strategies, and accelerating the development of low-carbon technologies. However, traditional forecasting models often face challenges related to information leakage and boundary effects. This study proposes a novel extended sliding window decomposition (ESWD) mechanism to prevent information leakage and mitigate boundary effects, thereby enhancing decomposition quality. Additionally, a fully data-driven multivariate empirical mode decomposition (MEMD) technique is incorporated to further improve the model’s capabilities. Partial decomposition operations, combined with high-resolution and full-utilization strategies, ensure mode consistency. An empirical analysis of China’s largest carbon market, using eight key indicators from energy, macroeconomics, international markets, and climate fields, validates the proposed model’s effectiveness. Compared to traditional LSTM and SVR models, the hybrid model achieves performance improvements of 66.6% and 23.5% in RMSE for closing price prediction, and 73.8% and 10.8% for opening price prediction, respectively. Further integration of LSTM and SVR strategies enhances RMSE performance by an additional 82.7% and 8.3% for closing prices, and 30.4% and 4.5% for opening prices. The extended window setup (EW10) yields further gains, improving RMSE, MSE, and MAE by 11.5%, 35.4%, and 23.7% for closing prices, and 4.5%, 8.4%, and 4.2% for opening prices. These results underscore the significant advantages of the proposed model in enhancing carbon price prediction accuracy and trend prediction capabilities.
How Informative Is the Marginal Information in a 2 × 2 Table for Assessing the Association Between Variables? The Aggregate Informative Index
Authors: Cheema Salman , Beh Eric J. , Hudson Irene L.
Published: November 2024

The analysis of aggregate data has received increasing attention in the statistical discipline over the past 20 years, with the ongoing development of a suite of techniques that are classified as ecological inference. Much of its development has been focused solely on estimating the cell frequencies in a 2 × 2 contingency table where only the marginal totals are given; an approach that has been received with mixed reviews. More recently, the focus has shifted toward analyzing the overall association structure, rather than on the estimation of cell frequencies. This article provides some insight into how informative the aggregate data in a single 2 × 2 contingency table are for assessing the association between the variables. This is achieved through the development of a new index, the aggregate informative index. This new index quantifies how much information, on a [0, 100] scale, is needed in the marginal information in a 2 × 2 contingency table to conclude that a statistically significant association exists between the variables. It is established that, unlike Pearson’s (and other forms of the) chi-squared statistic, this new index is immune to changes in the sample size. It is also shown that the new index remains stable when the 2 × 2 contingency table consists of extreme marginal information.
A Generalization of Fixed-Point Theorems for Mappings with a Contractive Iterate
Authors: Georgiev Valentin , Zlatanov Boyan
Published: November 2024

In this paper, a generalization of fixed-point mappings with an iterate at a point in complete metric spaces is shown, using the notions of T-closed sets and i-P-regularity/d-P-regularity, proving conditions for the existence and uniqueness of the fixed point. Examples are provided to illustrate the results and an application to coupled fixed points is shown.
A Practical Economic Order Quantity Model for Growing Items with Edible Yield and Constraints in Poultry Farming
Authors: Nobil Erfan , Nobil Amir Hossein
Published: November 2024

Growing items like chicken broilers play a critical role in consumption baskets; however, their real characteristics have been neglected in the research focusing on inventory models such as economic order quantity (EOQ). Mainstream research conducted in this field considers an approximation of the edible rate of chicken broilers in cost analysis. On the other hand, this subject was the objective of other research, and the function that represents the relationship between the weight and age of broilers was derived through extensive research. This study proposes an EOQ model that considers a realistic function for extracting the exact value of edible parts of broilers and the correct form of feeding function that is dependent on their age. In other words, this study not only addresses the challenge arising in the estimation of the edible part of broilers but also introduces another function to obtain the correct amount of feeding and nurturing cost of broilers. Solution methodology encompasses these mathematical functions and then provides a straightforward framework to find the optimal solution. An exact heuristic solution is obtained that considers the real factors, and then the approach is applied to case studies, and insights are derived to manage real situations for corporations.
CNN-CBAM-LSTM: Enhancing Stock Return Prediction Through Long and Short Information Mining in Stock Prediction
Authors: Ye Peijie , Zhang Hao , Zhou Xi
Published: November 2024

Deep learning, a foundational technology in artificial intelligence, facilitates the identification of complex associations between stock prices and various influential factors through comprehensive data analysis. Stock price data exhibits unique time-series characteristics; models emphasizing long-term data may miss short-term fluctuations, while those focusing solely on short-term data may not capture cyclical trends. Existing models that integrate long short-term memory (LSTM) and convolutional neural networks (CNNs) face limitations in capturing both long- and short-term dependencies due to LSTM’s gated transmission mechanism and CNNs’ limited receptive field. This study introduces an innovative deep learning model, CNN-CBAM-LSTM, which integrates the convolutional block attention module (CBAM) to enhance the extraction of both long- and short-term features. The model’s performance is assessed using the Australian Standard & Poor’s 200 Index (AS51), showing improvement over traditional models across metrics such as RMSE, MAE, R2, and RETURN. To further confirm its robustness and generalizability, Diebold–Mariano (DM) tests and model confidence set experiments are conducted, with results indicating the consistently high performance of the CNN-CBAM-LSTM model. Additional tests on six globally recognized stock indices reinforce the model’s predictive strength and adaptability, establishing it as a reliable tool for forecasting in the stock market.
Investigation of Ti0.92+xZr0.1−xCr1.0Mn0.6Fe0.4 Alloys for Use as 25 MPa Hydrogen Compression Materials
Authors: Li Jiadong , Guo Yinglin , Wang Xiaojiao , Zhang Dong , Yuan Zhenluo , Zhao Shiqian , Fan Yanping
Published: November 2024

Metal hydride hydrogen compressors have attracted great attention due to their reliable safety, environmental friendliness, and the absence of vibration and noise. Herein, the effects of Ti substitution for Zr on the crystal structure and hydrogen compressive performance of Ti0.92+xZr0.1−xCr1.0Mn0.6Fe0.4 (x = 0, 0.01, 0.02, and 0.03) are investigated systematically. Among the investigated alloys, the Ti0.94Zr0.08Cr1.0Mn0.6Fe0.4 alloy can be considered as a promising candidate for application with a hydrogen capacity of 1.67 wt.% under 8 MPa at 10 °C. Additionally, it exhibits excellent cyclic stability. The desorption pressure at 83.9 °C was determined to be 25 MPa by van’t Hoff fitting plots, which fulfills the requirement of producing over 25 MPa hydrogen pressure in water-bath environments with a high compression ratio of 3.08. The Ti0.94Zr0.08Cr1.0Mn0.6Fe0.4 alloy is very promising for hydrogen refueling applications in long-tube trailers and low-pressure gas cylinders.
Design of New Energy-Absorbing Lattice Cell Configuration by Dynamic Topology Optimization
Authors: Li Yongxin , Li Qinghua , He Xingxing , Li Shenshan , Wang Yongle
Published: November 2024

In this study, we focus on the new energy-absorbing lattice cell configuration designed by topology optimization. To address the difficulty involved in the quantitative description of densification in periodic lattice plastic deformation, in this study, we propose characterizing the plastic densification state of a porous structure with the maximum ratio of two adjacent equivalent plastic moduli in the nonlinear static analysis process. Then, dynamic topology optimization is carried out with the maximization of the absorbed energy as the objective and the densification strain as the constraint to obtain the new topological configuration of the energy-absorbing lattice cell. Finally, additive manufacturing and quasistatic testing of the new energy-absorbing lattice structure and body-centered cubic and face-centered cubic lattice structure is conducted. The results show that, under the same conditions, the strain energy absorbed by the energy-absorbing lattice is approximately 3.5 times that absorbed by the body-centered cubic structure and 2.8 times that absorbed by the face-centered lattice structure with a low impact speed of 5 m/s.
Inclusion-Based Model: Calculating Tooth Root Bending Strength Considering Steel Cleanliness
Authors: Eggert Christian , Mevissen Dieter , Westphal Christian , Brecher Christian
Published: November 2024

Current gear design guidelines and standards have given little or no consideration to the increase in strength that can be achieved by using ultra-clean steels. In order to fully exploit the potential of ultra-clean steels, it is therefore necessary to use higher-quality calculation methods that combine FEM stress calculations with local strength calculations. Therefore, the aim of this paper is to extend the inclusion-based model to allow for the calculation of the tooth root bending strength of gears with different steel cleanliness. For this purpose, a material analysis of 20MnCr5 with three different degrees of cleanliness is carried out and the respective material defect distribution is determined. In order to be able to represent the determined material defect distributions of the different cleanliness grades in the inclusion-based model, the model is extended accordingly, and a sensitivity analysis is carried out on the influence of the material defect distribution functions on the tooth root bending strength calculation. Finally, the model is applied to a pulsator test to verify the applicability of the model. The results of the verification show that the calculation of the mean bending strength of gears in pulsator investigations is generally possible with the extended inclusion-based model. The inclusion-based model thus offers the potential to improve the statistical significance of pulsator test results by supplementing the limited number of practical test points with the virtual test points of the inclusion-based model.
High-Cycle Fatigue Fracture Behavior and Stress Prediction of Ni-Based Single-Crystal Superalloy with Film Cooling Hole Drilled Using Femtosecond Laser
Authors: Li Zhen , Xu Yuanming , Liu Xinling , Liu Changkui , Tao Chunhu
Published: November 2024

A high-temperature, high-cycle fatigue test was conducted on a nickel-based single-crystal superalloy with a pore structure. Optical and scanning electron microscopy were utilized to examine the crack propagation paths and fatigue fracture surfaces at the macro and micro scales. The analysis of crack initiation and propagation related to the pore structure facilitated the development of a crack shape factor reflecting these distinct fracture behaviors. Predictions about the high-cycle fatigue stress experienced by the specimen were made, accompanied by an error analysis, providing critical insights for precise stress calculations and structural optimization in engine blade design. The results reveal that high-cycle fatigue cracks originate from corner cracks at pore edges, with the initial propagation displaying smooth crystallographic plane features. Subsequent stages show clear fatigue arc patterns in the propagation zones. The fracture surface exhibits the significant layering of oxide layers, primarily composed of NiO, with traces of CoO displaying columnar growth. AL2O3 is predominantly found at the interfaces between the matrix and oxide layers. Short and straight dislocations near the oxide layers and within the matrix suggest that dislocation multiplication and planar slip dominate the slip mechanisms in this alloy. The orientation of the fracture surface is mainly perpendicular to the load direction, with minor inclined facets in localized areas. Correlations were established between the plastic zone dimensions at the crack tips and the corresponding fatigue stresses. Without grain boundaries in single-crystal alloys, these dimensions are easily derived as parameters for fatigue stress analysis. The selected crack shape factor, “elliptical corner crack at pore edges”, captures the initiation and propagation traits relevant to porous structures. Subsequent calculations, accounting for the impact of oxide layers on stress assessments, indicated an error ratio ranging from 1.00 to 1.21 compared to nominal stress values.
Optimized Modeling Strategies for the Parametrization of a Two-Parameter Friction Model Through Inverse Modeling of Conical Tube-Upsetting Tests
Authors: Henze Michel , Koch Lena , Bailly David , Teller Marco , Hirt Gerhard
Published: November 2024

Friction is a critical influencing factor for a variety of forming processes, as it affects, for example, the required forming force. Complex models for the numerical description of friction often have two or more model parameters but lack appropriate calibration methods since calibration schemes developed for one-parameter models are not applicable. The objective of this work is to develop an evaluation method based on inverse modeling of the conical tube-upsetting test in order to allow for the parametrization of a two-parameter friction model, providing a unique solution for the model parameters. It is based on a comparison of the specimen’s outer contour for several points in time throughout the forming process according to the finite element model of the test. An optimization algorithm minimizes the deviation between the experimental and the simulated contour by adapting the friction model parameters. A two-parameter model is used that considers normal stress as well as relative velocity. First, purely numerical investigations show the necessity of a model adaption due to insufficient data. The modeling scheme is therefore adapted to consider data from two tests with different relative velocities. The results suggest a unique solution for the determination of the friction model parameters for purely numerical studies as well as for experimental conditions, comparing with the evolving contour of the conical tube-upsetting test specimen. Thus, this study presents a promising approach for the calibration of two-parameter friction models.
Design and Growth of P-Type AlGaN Graded Composition Superlattice
Authors: Liu Yang , Yang Xue , Zhou Xiaowei , Li Peixian , Yang Bo , Zhao Zhuang , Xiang Yingru , Bai Junchun
Published: November 2024

A graded composition superlattice structure is proposed by combining simulation with experimentation. The structural factors affecting graded symmetric superlattices and graded asymmetric superlattices and their action modes are simulated and analyzed. A Mg-doped graded symmetric superlattice structure with high Al content, excellent structural quality, good surface morphology and excellent electrical properties was grown by MOCVD equipment. The AlxGa1−xN superlattice with Al composition of 0.7 in the barrier exhibits a hole concentration of approximately 5 × 1015 cm−3 and a resistivity of 66 Ω·cm.
Screen-Printed PVDF Piezoelectric Pressure Transducer for Unsteadiness Study of Oblique Shock Wave Boundary Layer Interaction
Authors: Wang Bei , Corsi Cosimo , Weiland Thomas , Wang Zhenyu , Grund Thomas , Pohl Olaf , Bienia Johannes Max , Weiss Julien , Ngo Ha Duong
Published: November 2024

Shock wave boundary/layer interactions (SWBLIs) are critical in high-speed aerodynamic flows, particularly within supersonic regimes, where unsteady dynamics can induce structural fatigue and degrade vehicle performance. Conventional measurement techniques, such as pressure-sensitive paint (PSP), face limitations in frequency response, calibration complexity, and intrusive instrumentation. Similarly, MEMS-based sensors, like Kulite® sensors, present challenges in terms of intrusiveness, cost, and integration complexity. This study presents a flexible, lightweight polyvinylidene fluoride (PVDF) piezoelectric sensor array designed for high-resolution wall-pressure measurements in SWBLI research. The primary objective is to optimize low-frequency pressure fluctuation detection, addressing SWBLI’s need for accurate, real-time measurements of low-frequency unsteadiness. Fabricated using a double-sided screen-printing technique, this sensor array is low-cost, flexible, and provides stable, high-sensitivity data. Finite Element Method (FEM) simulations indicate that the sensor structure also has potential for high-frequency responses, behaving as a high-pass filter with minimal signal attenuation up to 300 kHz, although the current study’s experimental testing is focused on low-frequency calibration and validation. A custom low-frequency sound pressure setup was used to calibrate the PVDF sensor array, ensuring uniform pressure distribution across sensor elements. Wind tunnel tests at Mach 2 verified the PVDF sensor’s ability to capture pressure fluctuations and unsteady behaviors consistent with those recorded by Kulite sensors. The findings suggest that PVDF sensors are promising alternatives for capturing low-frequency disturbances and intricate flow structures in advanced aerodynamic research, with high-frequency performance to be further explored in future work.
Investigation on Influence Factors of Photo-Induced PLZT-Based Ion Drag Pump
Authors: Wang Xinjie , Lv Zhen , Shao Yuming , Shi Yujie , Yao Yao , Wang Jiong
Published: November 2024

The ion drag pump, as one kind of electrohydrodynamic pump, has received considerable attention in fluid applications due to its excellent pumping flow rate and pressure. However, there is a lack of systematic research about the factors that influence pumping performance of the ion drag pump. Here, a photo-induced ion drag pump based on the PLZT ceramic is proposed by combining the photoelectric effect and field emission phenomenon. The EHD model of this ion drag pump is constructed based on the mathematical model of the photovoltage of the PLZT ceramic, through which a series of finite element simulations are carried out to comprehensively investigate the factors that influence the pumping performance. The results demonstrate that such an ion drag pump is able to be improved by optimizing the electrode structure and fluid channel; increasing the light intensity; and providing a basic design guideline for applications of ion drag pumps in microfluidics, soft robots, and heat dissipation in micro devices.
A Novel MZI Fiber Sensor with Enhanced Curvature and Strain Sensitivity Based on Four-Core Fiber
Authors: Zhu Xiaojun , Chen Feijie , Zhuang Haoran , Qian Jiayi , Liu Hai , Cao Juan , Shi Yuechun , Wang Xia , Wu Wuming
Published: November 2024

We present a high-sensitivity curvature and strain Mach–Zehnder interferometer (MZI) fiber sensor based on a configuration of no-core fiber (NCF) and four-core fiber (FCF). We used an optical fiber fusion splicer to directly splice a segment of FCF between two segments of NCF, with both the FCF and NCF made of SiO2, where the FCF exhibits multi-path interference characteristics that allow for higher sensitivity. The NCF, with its self-focusing property, excites higher-order modes, which split and transmit it into the four cores of the FCF. The experimental results show that within a curvature range of 0.0104 m−1–0.1515 m−1, the maximum sensitivity can reach −78.04 dB/m−1 with a high linear value of ~0.99. Additionally, the strain response is also experimentally studied. In the range of 0–600 με, the maximum strain sensitivity is −6.49 pm/με. The sensor demonstrates high curvature and strain sensitivity, indicating its potential applications in sensing measurements.
Influence of Cu Content Variation on the Tribological Properties of Ni60CuMo with Sandwich-Structured Composite Coatings by Laser Cladding
Authors: Ji Fengqin , Li Xincheng , Zhang Songyang , Pang Ming
Published: November 2024

To enhance the tribological properties of the coatings and to inhibit cracking, sandwich-structured composite coatings were fabricated, consisting of a Ni60CuMo/IN718 transition layer and a Ni60CuMo/Ni-coated Cu wear-resistant layer with four different Ni-coated Cu contents. The results indicate that the transition layer inhibits the crack formation in the coating, and the refined grain structure stabilizes its average hardness at approximately 485 HV0.5. Increasing the Cu content in the wear-resistant layer exacerbates the segregation of the Cu-rich solid solution phases and refines the in situ-generated Cr7C3, TiC, and NbC phases. The average hardness of the wear-resistant layer decreases from 474 HV0.5 to 408 HV0.5 as the Ni-coated Cu content increases from zero to 75%. The coating with 50% Ni-coated Cu has the best Cu self-lubricating properties and exhibits the best wear resistance at both room and high temperatures. At room temperature, abrasive wear is the primary wear mechanism in the coatings. Although the ductility of the coatings is improved with increasing Cu content, excessive Cu reduces the hardness and load-bearing capacity. At 300 °C, oxidation wear becomes the dominant wear mechanism, accompanied by plastic deformation and three-body wear as the Cu content increases. At 500 °C, severe oxidation wear is the dominant mechanism, with excessive Cu leading to oxidation film failure.
Preparation and Characterization of Tiamulin-Loaded Niosomes for Oral Bioavailability Enhancement in Mycoplasma-Infected Broilers
Authors: Abonashey Shimaa G. , Fouad Amr Gamal , Hassan Hatem A. F. M. , El-Banna Ahmed H. , Shalaby Mostafa A. , Mobarez Elham , Fahmy Sherif Ashraf , El-Banna Hossny A.
Published: November 2024

Mycoplasma infections pose significant challenges in the poultry industry, necessitating effective therapeutic interventions. Tiamulin, a veterinary antibiotic, has demonstrated efficacy against Mycoplasma species. However, the emergence of resistant Mycoplasma species could dramatically reduce the therapeutic potential, contributing to economic losses. Optimizing the tiamulin’s pharmacokinetic profile via nanocarrier incorporation could enhance its therapeutic potential and reduce the administration frequency, ultimately reducing the resistant strain emergence. Niosomes, a type of self-assembled non-ionic surfactant-based nanocarrier, have emerged as a promising drug delivery system, offering improved drug stability, sustained release, and enhanced bioavailability. In this study, niosomal nanocarriers encapsulating tiamulin were prepared, characterized and assessed in Mycoplasma-inoculated broilers following oral administration. Differential scanning colorimetry (DSC) confirmed the alterations in the crystalline state following components integration into the self-assembled structures formed during the formulation procedure. Transmission electron microscopy (TEM) showed the spherical nanostructure of the formed niosomes. The formulated nanocarriers exhibited a zeta potential and average hydrodynamic diameter of −10.65 ± 1.37 mV and 339.67 ± 30.88 nm, respectively. Assessment of the pharmacokinetic parameters following oral administration to Mycoplasma gallisepticum-infected broilers revealed the ability of the niosomal nanocarriers to increase the tiamulin’s bioavailability and systemic exposure, marked by significantly higher area under the curve (AUC) (p < 0.01) and prolonged elimination half-life (T1/2) (p < 0.05). Enhanced bioavailability and prolonged residence time are crucial factors in maintaining therapeutic concentrations at reduced doses and administration frequencies. This approach provides a viable strategy to decrease the risk of subtherapeutic levels, thereby mitigating the development of antibiotic resistance. The findings presented herein offer a sustainable approach for the efficient use of antibiotics in veterinary medicine.
Whole-Genome Sequencing-Based Characterization of Clostridioides difficile Infection Cases at the University Hospital Centre Zagreb
Authors: Siroglavic Marko , Higgins Paul G. , Kanizaj Lucija , Ferencak Ivana , Juric Dragan , Augustin Goran , Budimir Ana
Published: November 2024

We investigated the intra-hospital distribution of C. difficile strains by whole-genome sequencing (WGS) of isolates collected in 2022 at the University Hospital Centre (UHC) Zagreb. In total, 103 patients with first-episode CDI in 2022 at UHC Zagreb were included, based on the screening stool antigen test for GDH (RidaQuick CD GDH; R-Biopharm AG, Germany), confirmed by Eazyplex C. difficile assays (Eazyplex CD assay; AmplexDiagnostics GmbH, Germany) specific for A, B, and binary toxins. Demographic and clinical data were retrospectively analyzed from electronic medical records. All samples were subjected to WGS analysis. Genetic clusters were formed from isolates with no more than six allelic differences according to core genome MLST. We identified six clusters containing 2–59 isolates with 15 singletons and 30 instances of possible intra-hospital transmission, mostly in the COVID-19 ward. WGS analysis proved useful in identifying clusters of isolates connecting various patient wards with possible transmission routes in the hospital setting. It could be used to support local and national surveillance of CDI infections and their transmission pathways.
Exploring the Linkage Between Ruminal Microbial Communities on Postweaning and Finishing Diets and Their Relation to Residual Feed Intake in Beef Cattle
Authors: Peraza Pablo , Fernández-Calero Tamara , Naya Hugo , Sotelo-Silveira José , Navajas Elly A.
Published: November 2024

Feed efficiency significantly impacts the economics of beef production and is influenced by biological and environmental factors. The rumen microbiota plays a crucial role in efficiency, with studies increasingly focused on its relationship with different rearing systems. This study analyzed 324 rumen samples from bulls and steers categorized as high and low efficiency based on residual feed intake. The animals were fed two diets (postweaning and finishing) and rumen samples were sequenced using a reduced representation sequencing (RRS) based approach. The results indicated that diet significantly affected microbial diversity and abundance. In postweaning diets, Actinomycetota, particularly Bifidobacterium, were prevalent, aiding carbohydrate fermentation. In contrast, Acetoanaerobium was identified in finishing diets, likely contributing to acetate production. Additionally, Bacteroides and Butyrivibrio were abundant during postweaning, known for fiber degradation and volatile fatty acid production. Notably, Prevotella and Fibrobacter succinogenes were associated with high feed intake and nutrient utilization, indicating their potential as microbial biomarkers. However, alpha diversity indices showed no significant relationship with feed efficiency, suggesting that diversity alone may not adequately reflect the complexity of feed efficiency phenotypes. These findings highlight the importance of diet and microbial interactions on feed efficiency and suggest further research to explore these microbial contributions to precision feeding strategies.
Susceptibility of Tambaqui (Colossoma macropomum) to Nile Tilapia-Derived Streptococcus agalactiae and Francisella orientalis
Authors: Reis Francisco Yan Tavares , Rocha Victória Pontes , Janampa-Sarmiento Peter Charrie , Santos Ágna Ferreira , Leibowitz Márcia Pimenta , Luz Ronald Kennedy , Pierezan Felipe , Gallani Sílvia Umeda , Tavares Guilherme Campos , Figueiredo Henrique César Pereira
Published: November 2024

Nile tilapia (Oreochromis niloticus) and tambaqui (Colossoma macropomum) are the two most produced freshwater fishes in Brazil. This study investigated the potential pathogenicity of Streptococcus agalactiae and Francisella orientalis, previously isolated from diseased Nile tilapia, to tambaqui. Experimental infection trials were conducted in juvenile tambaqui at a dose of approximately 107 CFU fish−1, assessing clinical signs, mortality, bacterial recovery, and histopathological changes. Results demonstrated that S. agalactiae exhibited high pathogenicity to tambaqui, causing rapid disease progression, high mortality (83.33%) within 48 h post-infection, and severe lesions in multiple organs, under the experimental conditions. In contrast, F. orientalis infection did not result in mortality or clinical signs, despite bacterial recovery and granulomatous inflammation observed in the tissues. This study highlights the need to consider the potential impact of these pathogens in tambaqui farming.
Five Years of Leaching Experiments to Evaluate Land Spreading of a Modified Bauxite Residue Before and After Treatment of Acid Mine Drainage: Sand or Soil Capping and Revegetation
Authors: Merdy Patricia , Parker Alexandre , Chen Chen , Hennebert Pierre
Published: November 2024

The global generation of bauxite residue necessitates environmentally responsible disposal strategies. This study investigated the long-term (5-year) behavior of bauxite residue whose pH was lowered to 8.5, called modified bauxite residue (MBR), using lysimeters to test various configurations: raw MBR or used MBR (UMBR) previously applied for acid mine drainage remediation, sand or soil capping, and revegetation. Throughout the experiment and across all configurations, the pH of the leachates stabilized between 7 and 8 and their salinity decreased. Their low sodium absorption ratio (SAR) indicated minimal risk of material clogging and suitability for salt-tolerant plant growth. Leaching of potentially toxic elements, except vanadium, decreased rapidly after the first year to low levels. Leachate concentrations consistently remained below LD50 for Hyalella azteca and were at least an order of magnitude lower by the experiment’s end, except for first-year chromium. Sand capping performed poorly, while revegetation and soil capping slightly increased leaching, though these were negligible given the low final leaching levels. Revegetated MBR shows promise as a suitable and sustainable solution for managing bauxite residues, provided the pH is maintained above 6.5. This study highlights the importance of long-term assessments and appropriate management strategies for bauxite residue disposal.
The Distinct Biological Effects of 6-Hydroxy-L-Nicotine in Representative Cancer Cell Lines
Authors: Postu Paula Alexandra , Boiangiu Razvan Stefan , Mihasan Marius , Stache Alexandru Bogdan , Tiron Adrian , Hritcu Lucian
Published: November 2024

6-hydroxy-L-nicotine (6HLN) is a nicotine (NIC) derivative with proven therapeutic potential in neurodegenerative disorders. Here, the impact of 6HLN on cell growth, migratory behavior, and inflammatory status of three different cancer cell lines (A549, MCF7, and U87) and two normal cell lines (16HBE14o and MCF10A) was investigated. In silico analyses were conducted to evaluate the binding affinity of 6HLN to nicotinic receptors (nAChRs) containing α9 and α5 subunits. The obtained in silico data revealed that 6HLN might act on the cholinergic system. Interestingly, the in vitro data showed the compound has cancer-stimulatory effects in U87 glioblastoma cells and cancer-inhibitory effects in MCF7 breast cancer cells. In A549 lung cancer cells, no changes were detected upon 6HLN administration. More importantly, 6HLN appears not to be deleterious for normal cells, with the viability of 16HBE14o pulmonary cells and MCF10A mammary cells remaining unchanged.
Emerging Fluorescent Nanoparticles for Non-Invasive Bioimaging
Authors: Khalid Asma , Tomljenovic-Hanic Snjezana
Published: November 2024

Fluorescence-based techniques have great potential in the field of bioimaging and could bring tremendous progress in microbiology and biomedicine. The most essential element in these techniques is fluorescent nanomaterials. The use of fluorescent nanoparticles as contrast agents for bioimaging is a large topic to cover. The purpose of this mini-review is to give the reader an overview of biocompatible and biodegradable fluorescent nanoparticles that are emerging nanomaterials for use in fluorescent bioimaging. In addition to the biocompatibility of these nanomaterials, biodegradability is considered a necessity for short-term sustainable bioimaging. Firstly, the main requirements for bioimaging are raised, and a few existing fluorescent nanoprobes are discussed. Secondly, a few inert biocompatible fluorescent nanomaterials for long-term bioimaging that have been, to some extent, demonstrated as fluorescent probes are reviewed. Finally, a few biocompatible and biodegradable nanomaterials for short-term bioimaging that are evolving for bioimaging applications are discussed. Together, these advancements signal a transformative leap toward sustainability and functionality in biomedical imaging.