bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Soil Physical Properties and Pre-Sowing Irrigation Depth from Electrical Resistivity, Moisture, and Salinity Measurements
Authors: Cordero-Vázquez Christian Y. , Delgado-Rodríguez Omar , Cisneros-Almazán Rodolfo , Peinado-Guevara Héctor J.
Published: April 2023

Seeds require adequate soil moisture prior to planting, and pre-sowing irrigation depth (PSID) represents the optimum seed moisture level. This work proposes a new methodology to obtain soil physical properties and PSID, that includes the application of the electromagnetic profiling method (EMP) as a fast and non-invasive technique. Soil electrical resistivity measurements obtained from an EMP survey are combined with soil moisture and salinity information as experimental input for the PetroWin program. The PetroWin program uses Ryjov’s theoretical model to determine fines content and porosity, and then, PSID values are determined. At the study site, variations in soil resistivity were controlled by variations in fines content and soil moisture, and not by variations in soil salinity. The rooting depth of the crops was limited by a soil thickness of 0.6 m. A PSID between 8 and 9 cm was determined for the site, resulting in a total water volume required of 5313 m3 to ensure that soil moisture reaches the field capacity. The proposed methodology constitutes an effective and efficient tool for the determination of the physical properties and irrigation parameters of agricultural soils and, consequently, for the sustainable use of irrigation water.
Do We Live Where It Is Pleasant? Correlates of Perceived Pleasantness with Socioeconomic Variables
Authors: Monteiro João , Carrilho Ana Clara , Sousa Nuno , Oliveira Leise Kelli de , Natividade-Jesus Eduardo , Coutinho-Rodrigues João
Published: April 2023

Living in urban areas is the wish of many people. However, with population growth in those areas, quality of life has become a concerning element for achieving sustainable cities. Because quality of life is influenced by the built environment, the state of the latter is a fundamental issue for public policies. This research expands on previous research on the perceived pleasantness of built environments by presenting a large-scale case study of the urban layout pleasantness in the central area of Belo Horizonte, Brazil, a typical global south city, and correlating pleasantness scores with socioeconomic factors to understand whether people do in fact live where the urban layout is more pleasant and how pleasantness and socioeconomic factors relate and contribute to one’s choice of living location. A comparison with the city of Coimbra, Portugal, representative of the global north, was also carried out. The findings showed that pleasantness tended to correlate negatively with urban density and positively with income. Possible explanations for these results and their generality are advanced.
Parkinson’s Disease and the Cardiac Cycle: A Rapid Literature Review and Case Series
Authors: Bardutz Holly , Singh Jyotpal , Rehman Ziaur , Bernat Patrick
Published: April 2023

Background and Objectives: Cardiac function in patients with Parkinson’s Disease (PD) is not well understood. We conducted a review of the literature to summarize all available data on the cardiac cycle in patients with PD and followed up the review with a case series to describe the cardiac cycle timing intervals in this patient population. Methods: Using the search terms (“Cardiac cycle” OR “echocardiography” OR “LVET” OR “IVCT” OR “IVRT” OR “LVEF” OR “Systolic Dysfunction” OR “Diastolic Dysfunction”) AND (“Parkinson’s Disease”), 514 studies were found with 19 included in the review. Results: Studies focused on the impact of medication, the presence of autonomic dysfunction, and resting-state, descriptive observational studies which considered the cardiac cycle. While inconsistent, the evidence suggests that patients with PD have some systolic dysfunction, with recent research implying the presence of subclinical systolic dysfunction. From the case series, 13 participants with PD were included and collected cardiac data daily for 6 weeks. Heart rate was consistent on a weekly basis at 67–71 bpm. Mean week-by-week cardiac parameters were also consistent with the systolic time interval at 332–348 ms, isovolumic relaxation time at 92–96 ms, and isovolumic contraction time at 34–36 ms. Conclusion: These timing intervals add valuable normative values for this patient population and the review of the literature suggests that more research is required to better understand cardiac cycle timing intervals in patients with Parkinson’s Disease.
Influence of Pre-Heat Treatment on the Deformation Behaviors, Microstructural Characteristics, and Mechanical Properties of a Continuously Cast Al-Cu-Mg Alloy during Continuous Extrusion Process
Authors: Qin Renbao , Chen Wentian , Tang Jie , Jiang Fulin , Chen Yonggang , Zhang Hui
Published: April 2023

The presence of a second phase in Al-Cu-MG alloys, with various sizes and supersaturation-solid-solubility, which can be changed by pre-heat-treatment, could have remarkable influence on hot workability and mechanical performance. In the present work, a continuously cast 2024 Al alloy was homogenized and then subjected to hot compression and continuous extrusion (Conform) along with the initial as-cast alloy. The results showed that the 2024 Al alloy specimen with pre-heat treatment had a higher resistance to deformation and dynamic recovery (DRV) during hot compression process compared with the as-cast sample. Meanwhile, dynamic recrystallization (DRX) was advanced in the pre-heat-treated sample. After the Conform Process, the pre-heat-treated sample also attained better mechanical properties without additional solid solution treatment. The higher supersaturation solid solubility and dispersoids generated during pre-heat treatment was proved to play a key role in restricting boundary migration, tangling dislocation motion and promoting the precipitation of S phase, which raised resistance to DRV and plastic deformation and enhanced the mechanical properties.
Modeling the Thermoelastic Bending of Ferric Oxide (Fe2O3) Nanoparticles-Enhanced RC Slabs
Authors: Harrat Zouaoui R. , Chatbi Mohammed , Krour Baghdad , Hadzima-Nyarko Marijana , Radu Dorin , Amziane Sofiane , Bachir Bouiadjra Mohamed
Published: April 2023

Nanoparticles, by virtue of their amorphous nature and high specific surface area, exhibit ideal pozzolanic activity which leads to the formation of additional C-S-H gel by reacting with calcium hydroxide, resulting in a denser matrix. The proportions of ferric oxide (Fe2O3), silicon dioxide (SiO2), and aluminum oxide (Al2O3) in the clay, which interact chemically with the calcium oxide (CaO) during the clinkering reactions, influence the final properties of the cement and, therefore, of the concrete. Through the phases of this article, a refined trigonometric shear deformation theory (RTSDT), taking into account transverse shear deformation effects, is presented for the thermoelastic bending analysis of concrete slabs reinforced with ferric oxide (Fe2O3) nanoparticles. Thermoelastic properties are generated using Eshelby’s model in order to determine the equivalent Young’s modulus and thermal expansion of the nano-reinforced concrete slab. For an extended use of this study, the concrete plate is subjected to various mechanical and thermal loads. The governing equations of equilibrium are obtained using the principle of virtual work and solved using Navier’s technique for simply supported plates. Numerical results are presented considering the effect of different variations such as volume percent of Fe2O3 nanoparticles, mechanical loads, thermal loads, and geometrical parameters on the thermoelastic bending of the plate. According to the results, the transverse displacement of concrete slabs subjected to mechanical loading and containing 30% nano-Fe2O3 was almost 45% lower than that of a slab without reinforcement, while the transverse displacement under thermal loadings increased by 10%.
Individual Effects of Alkali Element and Wire Structure on Metal Transfer Process in Argon Metal-Cored Arc Welding
Authors: Bui Hanh Van , Trinh Ngoc Quang , Tashiro Shinichi , Suga Tetsuo , Kakizaki Tomonori , Yamazaki Kei , Lersvanichkool Ackadech , Murphy Anthony B. , Tanaka Manabu
Published: April 2023

This study aimed to clarify the effect of wire structure and alkaline elements in wire composition on metal transfer behavior in metal-cored arc welding (MCAW). A comparison of metal transfer in pure argon gas was carried out using a solid wire (wire 1), a metal-cored wire without an alkaline element (wire 2), and another metal-cored wire with 0.084 mass% of sodium (wire 3). The experiments were conducted under 280 and 320 A welding currents, observed by high-speed imaging techniques equipped with laser assistance and bandpass filters. At 280 A, wire 1 showed a streaming transfer mode, while the others showed a projected one. When the current was 320 A, the metal transfer of wire 2 changed to streaming, while wire 3 remained projected. As sodium has a lower ionization energy than iron, the mixing of sodium vapor into the iron plasma increases its electrical conductivity, raising the proportion of current flowing through metal vapor plasma. As a result, the current flows to the upper region of the molten metal on the wire tip, with the resulting electromagnetic force causing droplet detachment. Consequently, the metal transfer mode in wire 3 remained projected. Furthermore, weld bead formation is the best for wire 3.
Adsorption Tuning of Polarity and Magnetism in AgCr2S4 Monolayer
Authors: Li Ranran , Wang Yu , Ding Ning , Dong Shuai , An Ming
Published: April 2023

As a recent successfully exfoliated non-van der Waals layered material, AgCrS2 has received a lot of attention. Motivated by its structure-related magnetic and ferroelectric behavior, a theoretical study on its exfoliated monolayer AgCr2S4 has been carried out in the present work. Based on density functional theory, the ground state and magnetic order of monolayer AgCr2S4 have been determined. The centrosymmetry emerges upon two-dimensional confinement and thus eliminates the bulk polarity. Moreover, two-dimensional ferromagnetism appears in the CrS2 layer of AgCr2S4 and can persist up to room temperature. The surface adsorption has also been taken into consideration, which shows a nonmonotonic effect on the ionic conductivity through ion displacement of the interlayer Ag, but has little impact on the layered magnetic structure.
Performance Evaluation of Radiation-Shielding Materials and Process Technology for Manufacturing Skin Protection Cream
Authors: Kim Seon-Chil
Published: April 2023

Personnel using X-ray devices, the main source of radiation in medical institutions, are primarily affected by scattered rays. When interventionists use radiation for examinations/treatments, their hands may enter the radiation-generating area. The shielding gloves used for protection against these rays restrict movement and cause discomfort. Here, a shielding cream that directly adheres to the skin was developed and examined as a personal protective device; further, its shielding performance was verified. Bismuth oxide and barium sulfate were selected as shielding materials and comparatively evaluated in terms of thickness, concentration, and energy. With increasing wt% of the shielding material, the protective cream became thicker, resulting in improved protection. Furthermore, the shielding performance improved with increasing mixing temperature. Because the shielding cream is applied to the skin and has a protective effect, it must be stable on the skin and easy to remove. During manufacturing, the bubbles were removed, and the dispersion improved by 5% with increasing stirring speed. During mixing, the temperature increased as the shielding performance increased by 5% in the low-energy region. In terms of the shielding performance, bismuth oxide was superior to barium sulfate by approximately 10%. This study is expected to facilitate the mass production of cream in the future.
Effect of Cr on Microstructure and Properties of WVTaTiCrx Refractory High-Entropy Alloy Laser Cladding
Authors: Xu Zhaomin , Sun Zhiping , Li Cheng , Wang Zhiming
Published: April 2023

WVTaTiCrx (x = 0, 0.25, 0.5, 0.75, 1) refractory high-entropy alloy coatings were prepared on a 42-CrMo steel plate using laser cladding. The purpose of this work is to investigate the effect of the Cr content on the microstructure and properties of the WVTaTiCrx coating. The morphologies and phase compositions of five coatings with different Cr contents were comparatively observed. In addition, the hardness and high-temperature oxidation resistance of the coatings were also analyzed. As a result, with the increase in Cr, the coating grains were more refined. All the coating is mainly composed of the BCC solid-solution phase, which promotes the precipitation of the Laves phase with the increase in Cr. The addition of Cr greatly improves the hardness, high-temperature oxidation resistance and corrosion resistance of the coating. The WVTaTiCr (Cr1) exhibited superior mechanical properties, especially in terms of its exceptional hardness, high-temperature oxidation resistance and outstanding corrosion resistance. The average hardness of the WVTaTiCr alloy coating reaches 627.36 HV. After 50 h of high-temperature oxidation, the oxide weight of WVTaTiCr increases by 5.12 mg/cm2, and the oxidation rate is 0.1 mg/(cm2·h). In 3.5 wt% NaCl solution, the corrosion potential of WVTaTiCr is −0.3198 V, and the corrosion rate is 0.161 mm/a.
Effect of Final Thermomechanical Treatment on the Mechanical Properties and Microstructure of T Phase Hardened Al-5.8Mg-4.5Zn-0.5Cu Alloy
Authors: Tao Kai , Xu Jingbo , Zhang Di , Zhang Aimin , Su Guang , Zhang Jishan
Published: April 2023

The effect of final thermomechanical treatment (FTMT) on the mechanical properties and microstructure of a T-Mg32(Al Zn)49 phase precipitation hardened Al-5.8Mg-4.5Zn-0.5Cu alloy was studied. The as-cold rolled aluminum alloy samples were subjected sequentially to solid solution treatment, pre-deformation, and two-stage aging treatment. Vickers hardness was measured during the aging process under various parameters. Tensile tests were conducted on the representative samples based on the hardness results. Microstructural characteristics were analyzed via transmission electron microscopy and high-resolution transmission electron microscopy. The conventional T6 process was also carried out for comparison. The hardness and tensile strength are increased evidently by the FTMT process for the Al-Mg-Zn-Cu alloy, while the ductility is adversely affected to a small extent. The precipitation at the T6 state consists of a coherent Guinier–Preston zone and T″ phase in the form of intragranular, fine, and spherical particles, while a semi-coherent T′ phase appears after the FTMT process as a new constituent. The distribution of dislocation tangles and isolated dislocations is another feature of FTMT samples. Enhanced precipitation hardening and dislocation strengthening account for the improved mechanical performance of FTMT samples.
Effect of the Consolidation Level on Organic Volatile Compound Emissions from Maize during Storage
Authors: Żytek Aleksandra , Rusinek Robert , Oniszczuk Anna , Gancarz Marek
Published: April 2023

The aim of this study was to determine the emission of organic volatile compounds from maize grain as a function of granularity and packing density of bulk material in conditions imitating processes occurring in silos. The study was carried out with the use of a gas chromatograph and an electronic nose, which was designed and constructed at the Institute of Agrophysics of PAS and has a matrix of eight MOS (metal oxide semiconductor) sensors. A 20-L volume of maize grain was consolidated in the INSTRON testing machine with pressures of 40 and 80 kPa. The control samples were not compacted, and the maize bed had bulk density. The analyses were carried out at a moisture content of 14% and 17% (w.b.—wet basis). The measurement system facilitated quantitative and qualitative analyses of volatile organic compounds and the intensity of their emission during 30-day storage. The study determined the profile of volatile compounds as a function of storage time and the grain bed consolidation level. The research results indicated the degree of grain degradation induced by the storage time. The highest emission of volatile compounds was recorded on the first four days, which indicated a dynamic nature of maize quality degradation. This was confirmed by the measurements performed with electrochemical sensors. In turn, the intensity of the volatile compound emission decreased in the next stage of the experiments, which showed a decline in the quality degradation dynamics. The sensor responses to the emission intensity decreased significantly at this stage. The electronic nose data on the emission of VOCs (volatile organic compounds) as well as grain moisture and bulk volume can be helpful for the determination of the quality of stored material and its suitability for consumption.
The Effect of Casting Technique and Severe Straining on the Microstructure, Electrical Conductivity, Mechanical Properties and Thermal Stability of the Al–1.7 wt.% Fe Alloy
Authors: Medvedev Andrey , Zhukova Olga , Enikeev Nariman , Kazykhanov Vil , Timofeev Victor , Murashkin Maxim
Published: April 2023

This paper features the changes in microstructure and properties of an Al–Fe alloy produced by casting with different solidification rates followed by severe plastic deformation and rolling. Particularly, different states of the as-cast Al–1.7 wt.% Fe alloy, obtained by conventional casting into a graphite mold (CC) and continuous casting into an electromagnetic mold (EMC), as well as after equal-channel angular pressing and subsequent cold rolling, were studied. Due to crystallization during casting into a graphite mold, particles of the Al6Fe phase are predominantly formed in the cast alloy, while casting into an electromagnetic mold leads to the formation of a mixture of particles, predominantly of the Al2Fe phase. The implementation of the two-stage processing by equal-channel angular pressing and cold rolling through the subsequent development of the ultrafine-grained structures ensured the achievement of the tensile strength and electrical conductivity of 257 MPa and 53.3% IACS in the CC alloy and 298 MPa and 51.3% IACS in the EMC alloy, respectively. Additional cold rolling led to a further reduction in grain size and refinement of particles in the second phase, making it possible to maintain a high level of strength after annealing at 230 °C for 1 h. The combination of high mechanical strength, electrical conductivity, and thermal stability can make these Al–Fe alloys a promising conductor material in addition to the commercial Al–Mg–Si and Al–Zr systems, depending on the evaluation of engineering cost and efficiency in industrial production.
Preparation and Lubricating Properties of Polystyrene Composite Microspheres
Authors: Zeng Wen , Huang Weiqing , Guo Bing , Sun Yang , Shen Hangyan
Published: April 2023

In order to improve the lubrication performance of polystyrene microspheres (PS) as solid lubricant in drilling fluids, elastic graphite–polystyrene composite microspheres (EGR/PS), montmorillonite–elastic graphite–polystyrene composite microspheres (OMMT/EGR/PS), and polytetrafluoroethylene–polystyrene composite microspheres (PTFE/PS) were prepared by suspension polymerization. OMMT/EGR/PS has a rough surface, while the surfaces of the other three composite microspheres are smooth. Among the four kinds of composite microspheres, the largest particle is OMMT/EGR/PS, and the average size is about 400 μm. The smallest particle is PTFE/PS, and the average size is about 49 μm. Compared with pure water, the friction coefficient of PS, EGR/PS, OMMT/EGR/PS and PTFE/PS reduced by 25%, 28%, 48%, and 62%, respectively. The wear tracks of EGR/PS, OMMT/EGR/PS and PTFE/PS are narrower and smoother than those of pure water. When the content of PTFE is 4.0 wt%, the friction coefficient and wear volume of PTFE/PS are 0.213 and 2.45 × 10−4 mm3—74% and 92.4% lower than that of pure water, respectively.
Identify the Micro-Parameters for Optimized Discrete Element Models of Granular Materials in Two Dimensions Using Hexagonal Close-Packed Structures
Authors: Zhou Xiaodong , Jin Dongzhao , Ge Dongdong , Chen Siyu , You Zhanping
Published: April 2023

The widely used simple cubic-centered (SCC) model structure has limitations in handling diagonal loading and accurately representing Poisson’s ratio. Therefore, the objective of this study is to develop a set of modeling procedures for granular material discrete element models (DEM) with high efficiency, low cost, reliable accuracy, and wide application. The new modeling procedures use coarse aggregate templates from an aggregate database to improve simulation accuracy and use geometry information from the random generation method to create virtual specimens. The hexagonal close-packed (HCP) structure, which has advantages in simulating shear failure and Poisson’s ratio, was employed instead of the SCC structure. The corresponding mechanical calculation for contact micro-parameters was then derived and verified through simple stiffness/bond tests and complete indirect tensile (IDT) tests of a set of asphalt mixture specimens. The results showed that (1) a new set of modeling procedures using the hexagonal close-packed (HCP) structure was proposed and was proved to be effective, (2) micro-parameters of the DEM models were transit form material macro-parameters based on a set of equations that were derived based on basic configuration and mechanism of discrete element theories, and (3) that the results from IDT tests prove that the new approach to determining model micro-parameters based on mechanical calculation is reliable. This new approach may enable a wider and deeper application of the HCP structure DEM models in the research of granular material.
Large Deviations for Hawkes Processes with Randomized Baseline Intensity
Authors: Seol Youngsoo
Published: April 2023

The Hawkes process, which is generally defined for the continuous-time setting, can be described as a self-exciting simple point process with a clustering effect, whose jump rate depends on its entire history. Due to past events determining future developments of self-exciting point processes, the Hawkes model is generally not Markovian. In certain special circumstances, it can be Markovian with a generator of the model if the exciting function is an exponential function or the sum of exponential functions. In the case of non-Markovian processes, difficulties arise when the exciting function is not an exponential function or a sum of exponential functions. The intensity of the Hawkes process is given by the sum of a baseline intensity and other terms that depend on the entire history of the point process, as compared to a standard Poisson process. It is one of the main methods used for studying the dynamical properties of general point processes, and is highly important for credit risk studies. The baseline intensity, which is instrumental in the Hawkes model, is usually defined for deterministic cases. In this paper, we consider a linear Hawkes model where the baseline intensity is randomly defined, and investigate the asymptotic results of the large deviations principle for the newly defined model. The Hawkes processes with randomized baseline intensity, dealt with in this paper, have wide applications in insurance, finance, queue theory, and statistics.
Attributed Graph Embedding with Random Walk Regularization and Centrality-Based Attention
Authors: Yang Yuxuan , Han Beibei , Ran Zanxi , Gao Min , Wei Yingmei
Published: April 2023

Graph-embedding learning is the foundation of complex information network analysis, aiming to represent nodes in a graph network as low-dimensional dense real-valued vectors for the application in practical analysis tasks. In recent years, the study of graph network representation learning has received increasing attention from researchers, and, among them, graph neural networks (GNNs) based on deep learning are playing an increasingly important role in this field. However, the fact that higher-order neighborhood information cannot be used effectively is a problem of most existing graph neural networks. Moreover, it tends to ignore the influence of latent representation and structural properties on graph embedding. In hopes of solving these issues, we introduce centrality encoding to learn the node properties, add an attention mechanism consideration to better distinguish the significance of neighboring nodes, and introduce random walk regularization to make sample neighbors that consistently satisfy predetermined criteria. This allows us to learn a representation of a potential node. We tested the performance of our model on node-clustering and link prediction tasks using three widely recognized benchmark datasets. The outcomes of our experiments demonstrate that our model significantly surpasses the baseline method in both tasks, indicating that the graph embedding it generates is highly expressive.
Imbalanced Ectopic Beat Classification Using a Low-Memory-Usage CNN LMUEBCNet and Correlation-Based ECG Signal Oversampling
Authors: Xie You-Liang , Lin Che-Wei
Published: April 2023

Objective: This study presents a low-memory-usage ectopic beat classification convolutional neural network (CNN) (LMUEBCNet) and a correlation-based oversampling (Corr-OS) method for ectopic beat data augmentation. Methods: A LMUEBCNet classifier consists of four VGG-based convolution layers and two fully connected layers with the continuous wavelet transform (CWT) spectrogram of a QRS complex (0.712 s) segment as the input of the LMUEBCNet. A Corr-OS method augmented a synthetic beat using the top K correlation heartbeat of all mixed subjects for balancing the training set. This study validates data via a 10-fold cross-validation in the following three scenarios: training/testing with native data (CV1), training/testing with augmented data (CV2), and training with augmented data but testing with native data (CV3). Experiments: The PhysioNet MIT-BIH arrhythmia ECG database was used for verifying the proposed algorithm. This database consists of a total of 109,443 heartbeats categorized into five classes according to AAMI EC57: non-ectopic beats (N), supraventricular ectopic beats (S), ventricular ectopic beats (V), a fusion of ventricular and normal beats (F), and unknown beats (Q), with 90,586/2781/7236/803/8039 heartbeats, respectively. Three pre-trained CNNs: AlexNet/ResNet18/VGG19 were utilized in this study to compare the ectopic beat classification performance of the LMUEBCNet. The effectiveness of using Corr-OS data augmentation was determined by comparing (1) with/without using the Corr-OS method and (2) the Next-OS data augmentation method. Next-OS augmented the synthetic beat using the next heartbeat of one subject. Results: The proposed LMUEBCNet can achieve a 99.4% classification accuracy under the CV2 and CV3 cross-validation scenarios. The accuracy of the proposed LMUEBCNet is 0.4–0.5% less than the performance obtained from AlexNet/ResNet18/VGG19 under the same data augmentation and cross-validation scenario, but the parameter usage is only 10% or less than that of the AlexNet/ResNet18/VGG19 method. The proposed Corr-OS method can improve ectopic beat classification accuracy by 0.3%. Conclusion: This study developed a LMUEBCNet that can achieve a high ectopic beat classification accuracy with efficient parameter usage and utilized the Corr-OS method for balancing datasets to improve the classification performance.
Coefficient Problems for a Class of Univalent Functions
Authors: Guo Dong , Tang Huo , Li Zongtao , Xu Qingbing , Ao En
Published: April 2023

In this paper, a new subclass has been defined as Ω of the univalent function in D={z∈C:|z|<1}. The central goal of this paper is to determine estimates for logarithmic coefficients, inverse logarithmic coefficients, some cases of the Hankel determinant and Zalcman functionals Jn,m of inverse functions.
Prediction of Tool Remaining Useful Life Based on NHPP-WPHM
Authors: Zhang Yingzhi , Guo Guiming , Yang Fang , Zheng Yubin , Zhai Fenli
Published: April 2023

A tool remaining useful life prediction method based on a non-homogeneous Poisson process and Weibull proportional hazard model (WPHM) is proposed, taking into account the grinding repair of machine tools during operation. The intrinsic failure rate model is built according to the tool failure data. The WPHM is established by collecting vibration information during operation and introducing covariates to describe the failure rate of the tool operation. In combination with the tool grinding repair, the NHPP-WPHM under different repair times is established to describe the tool comprehensive failure rate. The failure threshold of the tool life is determined by the maximum availability, and the remaining tool life is predicted. Take the cylindrical turning tool of the CNC lathe as an example, the root mean square error, mean absolute error, mean absolute percentage error, and determination coefficient (R2) are used as indicators. The proposed method is compared with the actual remaining useful life and the remaining useful life prediction model based on the WPHM to verify the effectiveness of the model.
A Second-Order Accurate Numerical Approximation for a Two-Sided Space-Fractional Diffusion Equation
Authors: Liu Taohua , Yin Xiucao , Chen Yinghao , Hou Muzhou
Published: April 2023

In this paper, we investigate a practical numerical method for solving a one-dimensional two-sided space-fractional diffusion equation with variable coefficients in a finite domain, which is based on the classical Crank-Nicolson (CN) method combined with Richardson extrapolation. Second-order exact numerical estimates in time and space are obtained. The unconditional stability and convergence of the method are tested. Two numerical examples are also presented and compared with the exact solution.
A New Discretization Scheme for the Non-Isotropic Stockwell Transform
Authors: Srivastava Hari M. , Tantary Azhar Y. , Shah Firdous A.
Published: April 2023

To avoid the undesired angular expansion of the sampling grid in the discrete non-isotropic Stockwell transform, in this communication we propose a scale-dependent discretization scheme that controls both the radial and angular expansions in unison. Based on the new discretization scheme, we derive a sufficient condition for the construction of Stockwell frames in L2(R2).
A Novel Coupled Meshless Model for Simulation of Acoustic Wave Propagation in Infinite Domain Containing Multiple Heterogeneous Media
Authors: Chi Cheng , Wang Fajie , Qiu Lin
Published: April 2023

This study presents a novel coupled meshless model for simulating acoustic wave propagation in heterogeneous media, based on the singular boundary method (SBM) and Kansa’s method (KS). In the proposed approach, the SBM was used to model the homogeneous part of the propagation domain, while KS was employed to model a heterogeneity. The interface compatibility conditions associated with velocities and pressures were imposed to couple the two methods. The proposed SBM–KS coupled approach combines the respective advantages of the SBM and KS. The SBM is especially suitable for solving external sound field problems, while KS is attractive for nonlinear problems in bounded non-homogeneous media. Moreover, the new methodology completely avoids grid generation and numerical integration compared with the finite element method and boundary element method. Numerical experiments verified the accuracy and effectiveness of the proposed scheme.
Role of Chemically Magnetized Nanofluid Flow for Energy Transition over a Porous Stretching Pipe with Heat Generation/Absorption and Its Stability
Authors: Zeeshan Zeeshan , Ahammad N. Ameer , Shah Nehad Ali , Chung Jae Dong , Attaullah Attaullah
Published: April 2023

The laminar movement in an expanding and contracting permeable pipe or surface has recently attracted the attention of many scholars owing to its application in engineering and biological processes. The objective of the current study is to examine the influence of chemical processes on magnetized nanofluid flow over extending or shrinking permeable pipes with a heat reservoir. The flow equations are renovated into first ODEs by introducing the new variable and then numerically solved by RK4 with a shooting procedure. The effect of emerging factors on the flow features is observed using graphs and elaborated in detail. From the analysis, the temperature is raised when the heat source is increased in both cases of wall expansion or contraction but declines in the case of heat sinks. In the case of a heat source, the temperature rises as the Hartmann and Prandtl numbers are enhanced, but in the case of a heat sink, the temperature falls. In the presence of heat sinks and injections, when the thermophoresis factor is increased, the concentration of nanoparticles is increased in both wall expansion and contractions. In both situations of wall extension or contraction, along with injection, the concentration of nanoparticles is a decreasing function of Nb, while the concentration of nanoparticles is an increasing function in the case of a heat source. Additionally, for the confirmation of the RK4 code, the total average square residue error and average square residue error are also presented. For the stability analysis, the current work is compared with published work, and excellent agreement is established. The novelty of the present study is to investigate the effect of chemical reaction on magnetized nanofluid flow over extending and shrinking porous pipes with heat generation and absorption.
Analytical Design of Optimal Model Predictive Control and Its Application in Small-Scale Helicopters
Authors: Hu Weijun , Quan Jiale , Ma Xianlong , Salah Mostafa M. , Shaker Ahmed
Published: April 2023

A new method for controlling the position and speed of a small-scale helicopter based on optimal model predictive control is presented in this paper. In the proposed method, the homotopy perturbation technique is used to analytically solve the optimization problem and, as a result, to find the control signal. To assess the proposed method, a small-scale helicopter system is modeled and controlled using the proposed method. The proposed method has been investigated under different conditions and its results have been compared with the conventional predictive control method. The simulation results show that the proposed technique is highly proficient in the face of various uncertainties and disturbances, and can quickly return the helicopter to its path.
Hydraulic Data Preprocessing for Machine Learning-Based Intrusion Detection in Cyber-Physical Systems
Authors: Mboweni Ignitious , Ramotsoela Daniel , Abu-Mahfouz Adnan
Published: April 2023

The protection of critical infrastructure such as water treatment and water distribution systems is crucial for a functioning economy. The use of cyber-physical systems in these systems presents numerous vulnerabilities to attackers. To enhance security, intrusion detection systems play a crucial role in limiting damage from successful attacks. Machine learning can enhance security by analysing data patterns, but several attributes of the data can negatively impact the performance of the machine learning model. Data in critical water system infrastructure can be difficult to work with due to their complexity, variability, irregularities, and sensitivity. The data involve various measurements and can vary over time due to changes in environmental conditions and operational changes. Irregular patterns and small changes can have significant impacts on analysis and decision making, requiring effective data preprocessing techniques to handle the complexities and ensure accurate analysis. This paper explores data preprocessing techniques using a water treatment system dataset as a case study and provides preprocessing techniques specific to processing data in industrial control to yield a more informative dataset. The results showed significant improvement in accuracy, F1 score, and time to detection when using the preprocessed dataset.
Efficient Solution of Burgers’, Modified Burgers’ and KdV–Burgers’ Equations Using B-Spline Approximation Functions
Authors: Parumasur Nabendra , Adetona Rasheed A. , Singh Pravin
Published: April 2023

This paper discusses the application of the orthogonal collocation on finite elements (OCFE) method using quadratic and cubic B-spline basis functions on partial differential equations. Collocation is performed at Gaussian points to obtain an optimal solution, hence the name orthogonal collocation. The method is used to solve various cases of Burgers’ equations, including the modified Burgers’ equation. The KdV–Burgers’ equation is considered as a test case for the OCFE method using cubic splines. The results compare favourably with existing results. The stability and convergence of the method are also given consideration. The method is unconditionally stable and second-order accurate in time and space.
Second Order Chebyshev–Edgeworth-Type Approximations for Statistics Based on Random Size Samples
Authors: Christoph Gerd , Ulyanov Vladimir V.
Published: April 2023

This article completes our studies on the formal construction of asymptotic approximations for statistics based on a random number of observations. Second order Chebyshev–Edgeworth expansions of asymptotically normally or chi-squared distributed statistics from samples with negative binomial or Pareto-like distributed random sample sizes are obtained. The results can have applications for a wide spectrum of asymptotically normally or chi-square distributed statistics. Random, non-random, and mixed scaling factors for each of the studied statistics produce three different limit distributions. In addition to the expected normal or chi-squared distributions, Student’s t-, Laplace, Fisher, gamma, and weighted sums of generalized gamma distributions also occur.
Isolation and Characterization of Targeting-HBsAg VNAR Single Domain Antibodies from Whitespotted Bamboo Sharks (Chiloscyllium plagiosum)
Authors: Jiang Xierui , Sun Shan , Li Zengpeng , Chen Mingliang
Published: April 2023

Immunoglobulin new antigen receptor (IgNAR) is a naturally occurring antibody that consists of only two heavy chains with two independent variable domains. The variable binding domain of IgNAR, called variable new antigen receptor (VNAR), is attractive due to its solubility, thermal stability, and small size. Hepatitis B surface antigen (HBsAg) is a viral capsid protein found on the surface of the Hepatitis B virus (HBV). It appears in the blood of an individual infected with HBV and is widely used as a diagnostic marker for HBV infection. In this study, the whitespotted bamboo sharks (Chiloscyllium plagiosum) were immunized with the recombinant HBsAg protein. Peripheral blood leukocytes (PBLs) of immunized bamboo sharks were further isolated and used to construct a VNAR-targeted HBsAg phage display library. The 20 specific VNARs against HBsAg were then isolated by bio-panning and phage ELISA. The 50% of maximal effect (EC50) of three nanobodies, including HB14, HB17, and HB18, were 4.864 nM, 4.260 nM, and 8.979 nM, respectively. The Sandwich ELISA assay further showed that these three nanobodies interacted with different epitopes of HBsAg protein. When taken together, our results provide a new possibility for the application of VNAR in HBV diagnosis and also demonstrate the feasibility of using VNAR for medical testing.
Inflammatory Cytokines, Redox Status, and Cardiovascular Diseases Risk after Weight Loss via Bariatric Surgery and Lifestyle Intervention
Authors: Abulmeaty Mahmoud M. A. , Ghneim Hazem K. , Alkhathaami Abdulaziz , Alnumair Khalid , Al Zaben Mohamed , Razak Suhail , Al-Sheikh Yazeed A.
Published: April 2023

Background and Objectives: Obesity is a chronic inflammatory condition and is considered a major risk factor for cardiovascular disease (CVD). The effects of obesity management via sleeve gastrectomy (SG) and lifestyle intervention (LS) on inflammatory cytokines, redox status, and CVD risk were studied in this work. Materials and Methods: A total of 92 participants (18 to 60 years old) with obesity (BMI ≥ 35 kg/m2 were divided into two groups: the bariatric surgery (BS) group (n = 30), and the LS group (n = 62). According to the achievement of 7% weight loss after 6 months, the participants were allocated to either the BS group, the weight loss (WL) group, or the weight resistance (WR) group. Assessments were performed for body composition (by bioelectric impedance), inflammatory markers (by ELISA kits), oxidative stress (OS), antioxidants (by spectrophotometry), and CVD risk (by the Framingham risk score (FRS) and lifetime atherosclerotic cardiovascular disease risk (ASCVD)). Measurements were taken before and after six months of either SG or LS (500 kcal deficit balanced diet, physical activity, and behavioral modification). Results: At the final assessment, only 18 participants in the BS group, 14 participants in the WL group, and 24 participants in the WR group remained. The loss in fat mass (FM) and weight loss were greatest in the BS group (p < 0.0001). Levels of IL-6, TNF-a, MCP-1, CRP, and OS indicators were significantly reduced in the BS and WL groups. The WR group had significant change only in MCP-1 and CRP. Significant reductions in the CVD risk in the WL and BS groups were detected only when using FRS rather than ASCVD. The FM loss correlated inversely with FRS-BMI and ASCVD in the BS group, whereas in the WL group, FM loss correlated only with ASCVD. Conclusions: BS produced superior weight and fat mass loss. However, both BS and LS produced a similar reduction in the inflammatory cytokines, relief of OS indicators, and enhancement of antioxidant capacity, and consequently reduced the CVD risk.
Novel High-Throughput Microwell Spectrophotometric Assay for One-Step Determination of Lorlatinib, a Novel Potent Drug for the Treatment of Anaplastic Lymphoma Kinase (ALK)-Positive Non-Small Cell Lung Cancer
Authors: Al-Hossaini Abdullah M. , Darwish Ibrahim A. , Darwish Hany W.
Published: April 2023

Background and Objectives: Lorlatinib (LOR) belongs to the third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors. People who are diagnosed with ALK-positive metastatic and advanced non-small cell lung cancer (NSCLC) are eligible to get it as a first-line treatment option after it was given the approval by “the Food and Drug Administration (FDA)”. However, no study has described constructing high-throughput analytical methodology for LOR quantitation in dosage form. For the first time, this work details the construction of a high-throughput, innovative microwell spectrophotometric assay (MW-SPA) for single-step assessment of LOR in its tablet form, for use in pharmaceutical quality control. Materials and Methods: Assay depended on charge transfer complex (CTC) formation between LOR, as electron donor, with 2,3-dichloro-3,5-dicyano-1,4-benzoquinone (DDQ), as π-electron acceptor. Reaction conditions were adjusted, the CTC was characterized by ultraviolet (UV)-visible spectrophotometry and computational molecular modeling, and its electronic constants were determined. Site of interaction on LOR molecule was allocated and reaction mechanism was suggested. Under refined optimum reaction conditions, the procedures of MW-SPA were performed in 96-well assay plates, and the responses were recorded by an absorbance plate reader. Validation of the current methodology was performed in accordance with guidelines of “the International Council on Harmonization (ICH)”, and all validation parameters were acceptable. Results: Limits of detection and quantitation of MW-SPA were 1.8 and 5.5 µg/well, respectively. The assay was applied with great success for determining LOR in its tablets. Conclusions: This The assay is straightforward, economic and has high-throughput characteristics. Consequently, the assay is recommended as a valuable analytical approach in quality control laboratories for LOR’s tablets’ analysis.
Green Methods for the Fabrication of Graphene Oxide Membranes: From Graphite to Membranes
Authors: Pedico Alessandro , Baudino Luisa , Aixalà-Perelló Anna , Lamberti Andrea
Published: April 2023

Graphene oxide (GO) has shown great potential as a membrane material due to its unique properties, including high mechanical strength, excellent thermal stability, versatility, tunability, and outperforming molecular sieving capabilities. GO membranes can be used in a wide range of applications, such as water treatment, gas separation, and biological applications. However, the large-scale production of GO membranes currently relies on energy-intensive chemical methods that use hazardous chemicals, leading to safety and environmental concerns. Therefore, more sustainable and greener approaches to GO membrane production are needed. In this review, several strategies proposed so far are analyzed, including a discussion on the use of eco-friendly solvents, green reducing agents, and alternative fabrication techniques, both for the preparation of the GO powders and their assembly in membrane form. The characteristics of these approaches aiming to reduce the environmental impact of GO membrane production while maintaining the performance, functionality, and scalability of the membrane are evaluated. In this context, the purpose of this work is to shed light on green and sustainable routes for GO membranes’ production. Indeed, the development of green approaches for GO membrane production is crucial to ensure its sustainability and promote its widespread use in various industrial application fields.
Effect of Slag Basicity on Non-Metallic Inclusions and Cleanliness of 15-5PH Stainless Steel
Authors: Zhan Zhonghua , Zhang Yanling , Shi Ruxing , Qiao Tong , Wang Guanbo , Cheng Guoguang
Published: April 2023

Few reports exist on the effect of the basicity of refining slag on inclusions in 15-5PH stainless steel and its removal efficiency. In this study, the effects of various basicities on the formation and removal efficiency of inclusions in molten steel were investigated. To investigate the effect of the chemical makeup of slag on the non-metallic inclusions in liquid steel, laboratory experiments and thermodynamic calculations were conducted on CaO-MgO-SiO2-Al2O3-CaF2 slag with various slag basicities and 15-5PH stainless steel. In the steel samples that had reacted with high-basicity slag samples, the magnesium content and aluminum yield were higher. Thermodynamic findings according to the ion and molecule coexistence theory showed that log (aSiO23/aAl2O32) decreases as slag basicity increases. This increases the Al concentration in liquid steel while decreasing the Si content. Log (aMgO3/aAl2O3) also increases, increasing the Mg content of the molten steel. With this, the transformation order of oxide inclusions is Al2O3 → MgAl2O4 → MgO. High-basicity slag increases the attachment of slag to inclusions and generates MgAl2O4 inclusions that are more easily adsorbed by inclusions in molten steel, thereby improving the cleanliness of molten steel.