bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of Chitosan Films with the Bioactive Substances—Caffeine and Propolis
Authors: Stefanowska Karolina , Woźniak Magdalena , Sip Anna , Mrówczyńska Lucyna , Majka Jerzy , Kozak Wojciech , Dobrucka Renata , Ratajczak Izabela
Published: July 2023

Chitosan is a natural and biodegradable polymer with promising potential for biomedical applications. This study concerns the production of chitosan-based materials for future use in the medical industry. Bioactive substances—caffeine and ethanolic propolis extract (EEP)—were incorporated into a chitosan matrix to increase the bioactivity of the obtained films and improve their mechanical properties. Acetic and citric acids were used as solvents in the production of the chitosan-based films. The obtained materials were characterized in terms of their antibacterial and antifungal activities, as well as their mechanical properties, including tensile strength and elongation at break. Moreover, the chemical structures and surface morphologies of the films were assessed. The results showed that the solution consisting of chitosan, citric acid, caffeine, and EEP exhibited an excellent antiradical effect. The activity of this solution (99.13%) was comparable to that of the standard antioxidant Trolox (92.82%). In addition, the film obtained from this solution showed good antibacterial activity, mainly against Escherichia coli and Enterococcus faecalis. The results also revealed that the films produced with citric acid exhibited higher activity levels against pathogenic bacteria than the films obtained with acetic acid. The antimicrobial effect of the chitosan-based films could be further enhanced by adding bioactive additives such as caffeine and propolis extract. The mechanical tests showed that the solvents and additives used affected the mechanical properties of the films obtained. The film produced from chitosan and acetic acid was characterized by the highest tensile strength value (46.95 MPa) while the chitosan-based film with citric acid showed the lowest value (2.28 MPa). The addition of caffeine and propolis to the film based on chitosan with acetic acid decreased its tensile strength while in the case of the chitosan-based film with citric acid, an increase in strength was observed. The obtained results suggested that chitosan films with natural bioactive substances can be a promising alternative to the traditional materials used in the medical industry, for example, as including biodegradable wound dressings or probiotic encapsulation materials.
Conv-ViT: A Convolution and Vision Transformer-Based Hybrid Feature Extraction Method for Retinal Disease Detection
Authors: Dutta Pramit , Sathi Khaleda Akther , Hossain Md. Azad , Dewan M. Ali Akber
Published: July 2023

The current advancement towards retinal disease detection mainly focused on distinct feature extraction using either a convolutional neural network (CNN) or a transformer-based end-to-end deep learning (DL) model. The individual end-to-end DL models are capable of only processing texture or shape-based information for performing detection tasks. However, extraction of only texture- or shape-based features does not provide the model robustness needed to classify different types of retinal diseases. Therefore, concerning these two features, this paper developed a fusion model called ‘Conv-ViT’ to detect retinal diseases from foveal cut optical coherence tomography (OCT) images. The transfer learning-based CNN models, such as Inception-V3 and ResNet-50, are utilized to process texture information by calculating the correlation of the nearby pixel. Additionally, the vision transformer model is fused to process shape-based features by determining the correlation between long-distance pixels. The hybridization of these three models results in shape-based texture feature learning during the classification of retinal diseases into its four classes, including choroidal neovascularization (CNV), diabetic macular edema (DME), DRUSEN, and NORMAL. The weighted average classification accuracy, precision, recall, and F1 score of the model are found to be approximately 94%. The results indicate that the fusion of both texture and shape features assisted the proposed Conv-ViT model to outperform the state-of-the-art retinal disease classification models.
Towards an Integrative Model of Math Cognition: Interactions between Working Memory and Emotions in Explaining Children’s Math Performance
Authors: Van der Ven Sanne H. G. , Prast Emilie J. , Van de Weijer-Bergsma Eva
Published: July 2023

Individual variation in mathematical skills can be ascribed to differences in cognitive ability, but also to students’ emotional experiences of mathematics, such as enjoyment and anxiety. The current study investigated how the interplay of working memory with math anxiety and enjoyment explains mathematical performance in primary school students. We also explored whether these relations differed with the type of math test and students’ age. Using mixed effect models, we reanalyzed data from 4471 Dutch primary school students (grades 2–6) who had completed two computerized working memory tasks, had filled out a questionnaire on math emotions, and had completed two math tests: story problems and speeded arithmetic. Findings showed that working memory, anxiety, and enjoyment were linear (but not curvilinear) predictors of performance on both tests, while some relations were stronger for the math (story)-problem-solving test. Higher math anxiety negatively impacted performance more strongly for students with stronger working memory skills, but only on the arithmetic test. No interaction between working memory and enjoyment was found. The relation between math anxiety and math performance increased with grade level, but no other age-related changes were found. Interpretations and recommendations focus on situated views on learning and emotion.
Optimal Path Planning Method for Unmanned Surface Vehicles Based on Improved Shark-Inspired Algorithm
Authors: Liang Jingrun , Liu Lisang
Published: July 2023

As crucial technology in the auto-navigation of unmanned surface vehicles (USVs), path-planning methods have attracted scholars’ attention. Given the limitations of White Shark Optimizer (WSO), such as convergence deceleration, time consumption, and nonstandard dynamic action, an improved WSO combined with the dynamic window approach (DWA) is proposed in this paper, named IWSO-DWA. First, circle chaotic mapping, adaptive weight factor and the simplex method are used to improve the initial solution and spatial search efficiency and accelerate the convergence of the algorithm. Second, optimal path information planned by the improved WSO is put into the DWA to enhance the USV’s navigation performance. Finally, the COLREGs rules are added to the global dynamic optimal path planning method to ensure the USV’s safe navigation. Compared with the WSO, the experimental simulation results demonstrate that the path length cost, steering cost and time cost of the proposed method are decreased by 13.66%, 18.78% and 79.08%, respectively, and the improvement in path smoothness cost amounts to 19.85%. Not only can the proposed IWSO-DWA plan an optimal global navigation path in an intricate marine environment, but it can also help a USV avoid other ships dynamically in real time and meets the COLREGs rules.
Haemoadsorption Combined with Continuous Renal Replacement Therapy in Abdominal Sepsis: Case Report Series
Authors: Sánchez-Morán Fernando , Mateu-Campos María Lidón , Bernal-Julián Francisco , Gil-Santana Ali , Sánchez-Herrero Ángeles , Martínez-Gaspar Teresa
Published: July 2023

In recent decades, multiple efforts have been made to identify targets and therapeutic measures in the host response to infection. Haemoadsorption, under the attractive theoretical premise of inflammatory response modulation through the adsorption of soluble inflammatory mediators, could have a place as an adjuvant therapy in septic patients. The development of new devices and the recent COVID-19 pandemic has renewed interest in this therapy. The aim of this report is to describe our experience in patients with abdominal sepsis for whom haemoadsorption with a neutral microporous resin column was added to conventional treatment and to describe its performance through patient cases in the absence of large randomised trials with this device. We present five patients with abdominal sepsis admitted to a Spanish intensive care unit in which haemoadsorption was used as adjuvant treatment. The key practical aspects of the treatment protocol have been used as a guide for conducting a multicentric study. Based on the experience gathered in these five cases, the potential benefit of haemoadsorption as adjuvant therapy in patients with abdominal sepsis with multiple organ failure after control of the source of infection and adequate treatment should be investigated. Likewise, it must be defined which patients can benefit from the therapy, the most appropriate biomarkers to guide the therapy, the ideal time of initiation and discontinuation, its potential side effects, and the interaction with other therapies, especially how such treatment affects the antibiotics levels.
Demonstrating the Use of the Yield-Gap Concept on Crop Model Calibration in Data-Poor Regions: An Application to CERES-Wheat Crop Model in Greece
Authors: Nikou Melpomeni , Mavromatis Theodoros
Published: July 2023

Yield estimations at global or regional spatial scales have been compromised due to poor crop model calibration. A methodology for estimating the genetic parameters related to grain growth and yield for the CERES-Wheat crop model is proposed based on yield gap concept, the GLUE coefficient estimator, and the global yield gap atlas (GYGA). Yield trials with three durum wheat cultivars in an experimental farm in northern Greece from 2004 to 2010 were used. The calibration strategy conducted with CERES-Wheat (embedded in DSSAT v.4.7.5) on potential mode taking into account the year-to-year variability of relative yield gap Yrg (YgC_adj) was: (i) more effective than using the average site value of Yrg (YgC_unadj) only (the relative RMSE ranged from 10 to 13% for the YgC_adj vs. 48 to 57% for YgC_unadj) and (ii) superior (slightly inferior) to the strategy conducted with DSSAT v.4.7.5 (DSSAT v.3.5—relative RMSE of 5 to 8% were found) on rainfed mode. Earlier anthesis, maturity, and decreased potential yield (from 2.2 to 3.9% for 2021–2050, and from 5.0 to 7.1% for 2071–2100), due to increased temperature and solar radiation, were found using an ensemble of 11 EURO-CORDEX regional climate model simulations. In conclusion, the proposed strategy provides a scientifically robust guideline for crop model calibration that minimizes input requirements due to operating the crop model on potential mode. Further testing of this methodology is required with different plants, crop models, and environments.
Maternal Age at Menarche Gene Polymorphisms Are Associated with Offspring Birth Weight
Authors: Reshetnikova Yuliya , Churnosova Maria , Stepanov Vadim , Bocharova Anna , Serebrova Victoria , Trifonova Ekaterina , Ponomarenko Irina , Sorokina Inna , Efremova Olga , Orlova Valentina , Batlutskaya Irina , Ponomarenko Marina , Churnosov Vladimir , Eliseeva Natalya , Aristova Inna , Polonikov Alexey , Reshetnikov Evgeny , Churnosov Mikhail
Published: July 2023

In this study, the association between maternal age at menarche (AAM)-related polymorphisms and offspring birth weight (BW) was studied. The work was performed on a sample of 716 pregnant women and their newborns. All pregnant women underwent genotyping of 50 SNPs of AAM candidate genes. Regression methods (linear and Model-Based Multifactor Dimensionality Reduction (MB-MDR)) with permutation procedures (the indicator pperm was calculated) were used to identify the correlation between SNPs and newborn weight (transformed BW values were analyzed) and in silico bioinformatic examination was applied to assess the intended functionality of BW-associated loci. Four AAM-related genetic variants were BW-associated including genes such as POMC (rs7589318) (βadditive = 0.202/pperm = 0.015), KDM3B (rs757647) (βrecessive = 0.323/pperm = 0.005), INHBA (rs1079866) (βadditive = 0.110/pperm = 0.014) and NKX2-1 (rs999460) (βrecessive = −0.176/pperm = 0.015). Ten BW-significant models of interSNPs interactions (pperm ≤ 0.001) were identified for 20 polymorphisms. SNPs rs7538038 KISS1, rs713586 RBJ, rs12324955 FTO and rs713586 RBJ–rs12324955 FTO two-locus interaction were included in the largest number of BW-associated models (30% models each). BW-associated AAM-linked 22 SNPs and 350 proxy loci were functionally related to 49 genes relevant to pathways such as the hormone biosynthesis/process and female/male gonad development. In conclusion, maternal AMM-related genes polymorphism is associated with the offspring BW.
Changes in Dento-Facial Morphology Induced by Wind Instruments, in Professional Musicians and Physical Exercises That Can Prevent or Improve Them—A Systematic Review
Authors: Macovei Georgiana , Minea Raluca , Dumitraș Iarina Teodora , Precup Cosmin Andrei , Baroiu Liliana , Nechifor Alexandru , Armencia Adina Oana , Lese Ana Cristina
Published: July 2023

The aim of this study is to highlight the changes that occur regarding dento-facial morphology, facial, and masticatory muscles in musicians who play wind instruments. Anatomical and functional changes may occur after the long-term use of each type of wind instrument. We considered studies of the impact of playing the wind instrument on the masticatory muscle activity and the resulting modifications. Both children and adults can be affected by playing wind instruments in regard to tooth positioning and facial morphology. These changes relate to the type of wind instruments, the type of vowels and tones used by instrumentalists. There most valuable breathing techniques have been identified that improve the redistribution of pressure, with a minimizing effect on the morphological changes in the oral cavity and cephalic extremity, implicitly on the masticatory functional disorders. In addition to these beneficial effects on the stomatognathic system, these breathing techniques favorably increase lung capacity. Furthermore, a series of toning exercises for neck muscles—which are actively involved and overworked by wind instrument-playing artists—was identified. The study concludes that less experienced instrumentalists demonstrate increased facial muscle engagement, possibly leading to excessive strain, while experienced instrumentalists exhibit more optimized patterns of muscle activity. The novelty of this research lies in its interdisciplinary approach to understanding the influence of wind instruments on dento-facial morphology, addressing preventive and corrective measures to mitigate undesirable outcomes.
Crosstalk between the Resident Microbiota and the Immune Cells Regulates Female Genital Tract Health
Authors: Santacroce Luigi , Palmirotta Raffaele , Bottalico Lucrezia , Charitos Ioannis Alexandros , Colella Marica , Topi Skender , Jirillo Emilio
Published: July 2023

The female genital tract (FGT) performs several functions related to reproduction, but due to its direct exposure to the external environment, it may suffer microbial infections. Both the upper (uterus and cervix) and lower (vagina) FGT are covered by an epithelium, and contain immune cells (macrophages, dendritic cells, T and B lymphocytes) that afford a robust protection to the host. Its upper and the lower part differ in terms of Lactobacillus spp., which are dominant in the vagina. An alteration of the physiological equilibrium between the local microbiota and immune cells leads to a condition of dysbiosis which, in turn, may account for the outcome of FGT infection. Aerobic vaginitis, bacterial vaginosis, and Chlamydia trachomatis are the most frequent infections, and can lead to severe complications in reproduction and pregnancy. The use of natural products, such as probiotics, polyphenols, and lactoferrin in the course of FGT infections is an issue of current investigation. In spite of positive results, more research is needed to define the most appropriate administration, according to the type of patient.
Synthesis, Crystal Structure and Anti-Leukemic Activity of (E)-Pyrrolo[1,2-a]quinoxalin-4-yl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one
Authors: Guillon Jean , Savrimoutou Solène , Albenque-Rubio Sandra , Pinaud Noël , Fillová Nina , Moreau Stéphane , Baylot Virginie , Desplat Vanessa
Published: July 2023

(E)-Pyrrolo[1,2-a]quinoxalin-4-yl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one was designed then synthesized using a multi-step pathway starting from commercially available 2-nitroaniline. Structure characterization of this original substituted pyrrolo[1,2-a]quinoxaline compound was achieved by using FT-IR, 1H-NMR, 13C-NMR, X-Ray and HRMS spectral analysis. This new pyrroloquinoxaline shows interesting cytotoxic potential against different human leukemia cell lines (MV4-11, K562, MOLM14 and Jurkat cells).
Effect of Reducing the Size and Number of Faces of Polyhedral Specimen on Wood Characterization by Ultrasound
Authors: Bertoldo Cinthya , Pereira Geise Aparecida , Gonçalves Raquel
Published: July 2023

The complete characterization of wood, with the determination of the 12 elastic constants that represent its orthotropy, is greatly relevant in applications employing structural calculation software programs. Ultrasound allows for such characterization with relative simplicity when compared to other methods. The polyhedron is considered the most appropriate specimen format for allowing the 12 constants to be calculated with a single specimen, and the traditionally used one is the 26-sided polyhedron, which, to be produced manually with more precision in directing the main directions of the wood, needs larger faces. The accuracy of this technique tends to be reduced when increasing the growth rings’ inclination since the waves deviate from the main directions of orthotropy. This research aimed to verify whether it is possible to reduce the polyhedra dimension without affecting the results of the elastic parameters obtained in wood characterization by ultrasound. The results indicate that the dimension of the polyhedron can be reduced without prejudice to the results of the elastic parameters obtained by the ultrasound test and that, in the manual production process of the specimen, the best way to make this reduction is to eliminate the faces unused in the test, changing the polyhedron to 18 faces instead of 26. Reducing the number of faces simplifies the manufacturing process and thus increases the possibility of producing specimens with straighter growth rings and better-directed symmetry axes.
Influence of Fiber Orientation on the Water and Ions Transportation of Engineered Cementitious Composite (ECC)
Authors: Tawfek Abdullah M. , Ge Zhi , Li Jian , Zhang Kangkang , Jiang Nengdong , Shao Yingxuan , Ling Yifeng , Šavija Branko
Published: July 2023

An engineered cementitious composite (ECC) belongs to a type of high-performance fiber-reinforced materials. Fiber alignment causes the anisotropy of such materials. Herein, the influence of the fiber orientation on water and ion penetration into an ECC was studied. Fiber alignment was achieved using an extrusion approach. Water absorption, sorptivity, chloride penetration resistance, sulfate attack resistance, and freezing–thawing resistance of specimens with fiber aligned horizontally (AH), vertically (AV), and randomly (R), corresponding to the direction of the exposure surface that was studied. The results showed that fibers oriented perpendicular to the water path delayed water migration into the ECC matrix. The sorptivity was significantly affected by the fiber direction. The sorptivity of the AH specimens was 35% and 13% lower than that of the AV and R specimens, respectively. After 180 days of exposure, the chloride penetration depth of the AH specimens was 5.7 mm, which is 13.6% and 20.8% lower than that of the AV and R specimens, respectively. The sulfate ingress profile indicates that the fiber–matrix interface oriented perpendicular to the penetration path can effectively delay sulfate migration. The fiber orientation also influences the compressive strength gain under immersion conditions (Na2SO4 solution, Na2SO4 + NaCl solution, and water). Compared with the AH and R specimens, the AV specimens are more sensitive to the immersion condition. In contrast, the fiber orientation has no significant effect on ECC specimens under freeze–thaw cycles. These findings indicate that controlling the fiber alignment and orientation in an ECC can improve its durability under certain exposure conditions.
Three-Dimensional Macroporous rGO-Aerogel-Based Composite Phase-Change Materials with High Thermal Storage Capacity and Enhanced Thermal Conductivity
Authors: Tao Zhang , He Wei , Xu Xiaoliang , Fan Jianzhong , Zhang Zhifeng , Yang Ziyue , Liu Yanqiang , Ma Heng , Qian Miao , Yang Mu
Published: July 2023

Three-dimensional porous network encapsulation strategy is an effective means to obtain composite phase-change materials (PCMs) with high heat storage capacity and enhanced thermal conductivity. Herein, macroporous reduced graphene oxide (rGO) aerogels with adjustable pore size are prepared by the emulsion template method and hydrothermal reduction process. Further, the shape-stabilized rGO-aerogel-based composite PCMs are constructed after the combination of 3D porous rGO supports and paraffin wax (PW) through vacuum melting infiltration. By regulating the pore structure of the rGO aerogel network, the rGO-based composite PCMs achieve excellent energy storage properties with a phase-change enthalpy of 179.94 J/g for the loading amount of 95.61 wt% and an obvious enhancement in thermal conductivity of 0.412 W/m−1·K−1, which is 54.89% higher than pristine PW and enduring thermal cycling stability. The obtained macroporous rGO-aerogel-based composite PCMs with high thermal storage and heat transfer performance effectively broaden the application of PCMs in the field of thermal energy storage.
Study on Elastic Mixed Mode Fracture Behavior and II-III Coupling Effect
Authors: Miao Xinting , Zhang Jinbo , Hong Haisheng , Peng Jian , Zhou Binbin , Li Qianqian
Published: July 2023

Mixed mode fracture is a widely studied topic, while the coupling effects of mixed mode cracking are unclear. In this paper, elastic fracture behaviors and the coupling effects of the mixed mode cracks are studied in detail based on the finite element method, experimental study and linear elastic fracture mechanics. Results show that there always exist II-III coupling effects at the crack tips of mixed mode cracks, which have many effects on the crack tip field and crack propagation behavior. It is found that a mode II component at the tip of a mixed mode crack is the main reason for crack deflection, while the mode III components show no effect. For any mixed mode crack, mode II components at the crack tip can be divided as that by mode II loading which causes plane crack propagation, and by the coupling effect which causes spatial crack propagation. On this basis, a new fracture criterion suitable for any mixed mode crack is proposed, combined with the coupling effect and the linear elastic superposition principle. The research in this paper provides a solution to the problem of an II-III coupling effect in mixed mode fracture research and further promotes the development of fracture mechanics.
Study on Adhesion Performance and Aging Strength Degradation Mechanism of SBS Modified Asphalt with Different Anti-Aging Additive
Authors: Zhuang Chuanyi , Guo Hao , Li Fengxiang , Hao Yan , Chen Kun , Li Gen , Ye Yali
Published: July 2023

After aging, the adhesiveness of asphalt deteriorates, leading to a reduction in the durability of asphalt mixtures and affecting the service life of asphalt pavements. To enhance the anti-aging performance of asphalt, this study employed the method of melt blending to prepare three types of modified asphalt: graphene/SBS modified asphalt (G/SBSMA), crumb rubber/SBS modified asphalt (CR/SBSMA), and petroleum resin/SBS modified asphalt (PR/SBSMA). Different dosages of the three types of modified asphalt were tested for changes in conventional performance indicators. The optimal dosages of graphene, crumb rubber, and C9 petroleum resin were determined to be 2%, 15%, and 5%, respectively. Based on the theory of surface free energy, the effects of anti-aging agents on the microscopic properties of SBS modified asphalt before and after aging were analyzed using the three-liquid method. The mechanisms of strength attenuation at the asphalt–aggregate interface under water exposure and aging were revealed. The results showed that with the increase of aging gradient, the asphalt-aggregate biphasic system became more active. The cohesive energy and peel energy of SBS modified asphalt increased continuously, while the adhesive energy decreased continuously, leading to a decrease in the energy ratio parameter. Resin-based anti-aging agents exhibited the most significant improvement in asphalt adhesion performance, while graphene demonstrated a more stable enhancement in asphalt’s water stability during the aging stage.
Physical, Mechanical, and Microstructure Characteristics of Ultra-High-Performance Concrete Containing Lightweight Aggregates
Authors: Abadel Aref A.
Published: July 2023

This study explores and enhances the resistance of an ultra-high-performance concrete (UHPC) to explosive spalling under elevated temperatures. This study investigates the impact of lightweight aggregates (LWAs) on the mechanical and microstructural properties of the UHPC. Various UHPC specimens were created by replacing silica sand with LWAs in percentages ranging from 0% to 30%. The evaluation of these specimens involved assessing their compressive and flexural strengths, density, mass loss, shrinkage, porosity, and microstructural characteristics using scanning electron microscopy (SEM). This study provides valuable insights by analyzing the influence of lightweight aggregates on the strength, durability, and microstructure of UHPC. The results reveal that incorporating LWAs in the UHPC improved its flowability while decreasing its density, as the percentage of LWAs increased from 5% to 30%. Including 30% LWA resulted in a mass loss of 4.8% at 300 °C, which reduced the compressive and flexural strengths across all curing durations. However, the UHPC samples subjected to higher temperatures displayed higher strength than those exposed to ambient conditions. The microstructure analysis demonstrated that the UHPC specimens with 30% LWA exhibited increased density due to continuous hydration from the water in the lightweight aggregate. The pore size distribution graph indicated that incorporating more of the LWA increased porosity, although the returns diminished beyond a certain point. Overall, these findings offer valuable insights into the influence of lightweight aggregates on the physical and strength characteristics of UHPC. This research holds significant implications for developing high-performance, lightweight concrete materials.
Stability Analysis of Shear Deformable Inhomogeneous Nanocomposite Cylindrical Shells under Hydrostatic Pressure in Thermal Environment
Authors: Sofiyev Abdullah H. , Fantuzzi Nicholas
Published: July 2023

In this study, the stability of inhomogeneous nanocomposite cylindrical shells (INCCSs) under hydrostatic pressure in a thermal environment is presented. The effective material properties of the inhomogeneous nanocomposite cylindrical shell are modeled on the basis of the extended mixture rule. Based on the effective material properties, the fundamental relations and stability equations are derived for thermal environments. In this process, the first-order shear deformation theory (FSDT) for the homogeneous orthotropic shell is generalized to the inhomogeneous shell theory. This is accomplished using the modified Donnell-type shell theory. The analytical expressions are obtained for hydrostatic buckling pressure of INCCSs in the framework of FSDT and classical shell theory (CST) by obtaining a solution based on Galerkin’s procedure. The numerical examples presented include both comparisons and original results. The last section shows the influences of carbon nanotube (CNT) models, volume fraction, and shell characteristics on the hydrostatic buckling pressure in the thermal environment.
Effect of Blade Geometry on γ′ Lattice Parameter and Primary Orientation of SX Cored Turbine Blades (II)
Authors: Krawczyk Jacek , Bogdanowicz Włodzimierz , Sieniawski Jan
Published: July 2023

The distributions of the lattice parameter of the γ′-phase (aγ′) and angular components of the primary crystal orientation along the lines parallel to the main axis of the single-crystalline CMSX 4-cored turbine blades were studied. The studies were carried out on the regions of the blades located far from the selector and its continuer extension (CE), positioned asymmetrically relative to the blade’s axis. It was found that, similarly to the regions of the blade located close to the CE (studied in part I), at the level of the blade related to the change of its cross-section, there were correlated local changes in aγ′ and the angular components of the primary crystal orientation representing the bending of the dendrites. However, the correlation was less clear due to the presence of low-angle boundaries (LABs) and the intensification of the consequences of the “fanning effect” in the regions far from the CE. It was found that the range of local changes in aγ′ and the angular components of the primary crystal orientation of the blade regions were influenced by both the distance from the CE and the separation of these regions from the CE by surfaces of the cooling bores. It was found that the deviation angle in the [001] direction from the blade axis increased with an increase in the distance from the CE. Based on the aγ′ changes, differences in the alloying element concentration near the cooling bores were discussed.
Effect of Traverse Speed Variation on Microstructural Properties and Corrosion Behavior of Friction Stir Welded WE43 Mg Alloy Joints
Authors: Khan Yusra Saman , Abidi Mustufa Haider , Malik Waqar , Lone Nadeem Fayaz , Aboudaif Mohamed K. , Mohammed Muneer Khan
Published: July 2023

The growing demand for Magnesium in the automotive and aviation industries has enticed the need to improve its corrosive properties. In this study, the WE43 magnesium alloys were friction stir welded (FSW) by varying the traverse speed. FSW eliminates defects such as liquefication cracking, expulsion, and voids in joints encountered frequently in fusion welding of magnesium alloys. The microstructural properties were scrutinized using light microscopy (LM) and scanning electron microscopy (SEM). Additionally, the elemental makeup of precipitates was studied using electron dispersive X-ray spectroscopy (EDS). The electrochemical behavior of specimens was evaluated by employing potentiodynamic polarization tests and was correlated with the microstructural properties. A defect-free weldment was obtained at a traverse and rotational speed of 100 mm/min and 710 rpm, respectively. All weldments significantly improved corrosion resistance compared to the base alloy. Moreover, a highly refined microstructure with redistribution/dissolution of precipitates was obtained. The grain size was reduced from 256 µm to around 13 µm. The corrosion resistance of the welded sample was enhanced by 22 times as compared to the base alloy. Hence, the reduction in grain size and the dissolution/distribution of secondary-phase particles within the Mg matrix are the primary factors for the enhancement of anti-corrosion properties.
Development of Clay-Composite Plasters Integrating Industrial Waste
Authors: Hegyi Andreea , Petcu Cristian , Ciobanu Adrian Alexandru , Calatan Gabriela , Bradu Aurelia
Published: July 2023

This research investigates the feasibility of developing clay composites using natural materials and incorporating waste by-products suitable for plastering diverse support structures. The study identified a versatile composition suitable for a wide range of support materials and explored the potential of revaluing industrial waste and by-products by reintegrating them into the Circular Economy. The experimental investigation outlines the process of evaluating the influence of different raw materials on the performance of the clay composite. The findings confirm that using limestone sludge and fly ash as additives to clay contributes to reducing axial shrinkage and increasing mechanical strengths, respectively. The optimal percentage of additives for the clay used are identified and provided. Using hydraulic lime as a partial substitute for clay reduces the apparent density of dried clay composites, axial shrinkage, and fissures formation while improving adhesion to the substrate. Introducing dextrin into this mix increases the apparent density of the hardened plaster while keeping axial shrinkage below the maximum threshold indicated by the literature. Mechanical strengths improved, and better compatibility in terms of adhesion to the support was achieved, with composition S3 presenting the best results and a smooth, fissure-free plastered surface after drying.
Additively Manufactured Parts from AA2011-T6 Large-Diameter Feedstocks Using Friction Stir Deposition
Authors: Alsaleh Naser A. , El-Sayed Seleman Mohamed M. , Hassan Ahmed M. M. , Ahmed Mohamed M. Z. , Ataya Sabbah , Latief Fahamsyah H. , Abdul-Latif Akrum , Habba Mohamed I. A.
Published: July 2023

The current work investigates the possibility of fabricating additive manufacturing products in solid-state form, from AA2011-T6 of 40 mm diameter rods as a feedstock, using an additive friction stir deposition (A-FSD) technique. The use of large diameter feedstocks, especially high-strength aluminum alloys (2XXX series), is a challenge, as it necessitates high power and the critical selection of the optimal A-FSD parameters, such as feed rate and spindle rotation speed. The study included applying a wide range of spindle rotation speeds, ranging from 400 to 1200 rpm, at three levels of feeding rates of 1, 3, and 5 mm/min. The AA2011-T6 friction stir deposited parts (FSDPs) were visually evaluated. This was followed by an examination of macrostructures through the thickness of the fabricated specimens. The characterization of microstructures was also carried out using optical microscopy and a scanning electron microscope equipped with advanced EDS analysis. Furthermore, the mechanical properties in terms of hardness and compressive strength of the AA2011-T6 base material (BM) and deposited materials were evaluated. Sound, additively manufactured products were successfully fabricated from 40 mm diameter AA2011-T6 feedstocks using the suggested deposition variables of 600 and 800 rpm spindle speeds and feeding rates of 1, 3, and 5 mm/min. The results indicated that the spindle speed and feeding rate govern the quality of the FSDPs. Furthermore, the axial load during the A-FSD process increased with increasing these parameters. In comparison to the AA2011-T6 BM, the additively deposited materials showed a refined grain structure and uniform dispersion of the fragment precipitates in their continuous multi-layers. The reduction ratio in grain size attains 71.56%, 76%, and 81.31% for the FSDPs processed at 800 rpm spindle speed and feeding rates of 1, 3 and 5 mm/min, respectively, compared to the grain size of BM. The Al2Cu and Al7Cu2Fe intermetallics are detected in the AA2011-T6 BM, and their deposited parts are in different shapes of spherical, almost spherical, irregular, and rod-like shapes. The compressive strength and hardness of the deposited parts increased with increasing spindle speed and feeding speeds. At a spindle speed of 800 rpm and a 5 mm/min feeding rate, the higher hardness and compressive strength gained were 85% and 93%, respectively, from that of the AA2011-T6 feedstock.
Effect of Si Contents on the Properties of Ti15Mo7ZrxSi Alloys
Authors: Jimenez-Marcos Cristina , Mirza-Rosca Julia Claudia , Baltatu Madalina Simona , Vizureanu Petrica
Published: July 2023

The main purpose of this research is to evaluate the mechanical characteristics and biocompatibility of two novel titanium alloys, Ti15Mo7ZrxSi (x = 0, 0.5, 0.75, 1). These samples had already undergone grinding, polishing, cutting, and chipping. Electrochemical, metallographic, three-point bending, and microhardness studies were conducted on the studied materials to determine their corrosion behavior, microstructure, Young’s modulus, and hardness. The first investigations revealed that both samples had biphasic and dendritic structures, elastic moduli that were between the highest and minimum values achieved by around 20 GPa, and favorable behavior when in contact with physiological fluids at ambient temperature. Ti15Mo7Zr0.5Si and Ti15Mo7Zr0.75Si, the research samples, had greater corrosion potentials, reduced corrosion rates, and therefore higher corrosion resistance, as well as modulus of elasticity values that were comparable to and closer to those of human bone. The results of this investigation indicate that both alloys exhibit favorable corrosion behavior, great biocompatibility, Young’s modulus results lower than those of conventional alloys used in biomedical implants, and hardness values higher than commercially pure titanium.
Stent-Graft Fabrics Incorporating a Specific Corona Ready to Fenestrate
Authors: Lin Jing , Guan Xiaoning , Nutley Mark , Panneton Jean M. , Zhang Ze , Guidoin Robert , Wang Lu
Published: July 2023

In situ fenestration of endovascular stent-grafts has become a mainstream bailout technique to treat complex emergent aneurysms while maintaining native anatomical visceral and aortic arch blood supplies. Fabric tearing from creating the in situ fenestration using balloon angioplasty may extend beyond the intended diameter over time. Further tearing may result from the physiologic pulsatile motion at the branching site. A resultant endoleak at the fenestrated sites in stent-grafts could ultimately lead to re-pressurization of the aortic sac and, eventually, rupture. In an attempt to address this challenge, plain woven fabrics were designed. They hold a specific corona surrounding a square-shaped cluster with a plain weave fabric structure, a 2/2 twill, or a honeycomb. The corona was designed to stop potential further tearing of the fabric caused by the initial balloon angioplasty and stent or later post-implantation motion. The cluster within the corona was designed with relatively loose fabric structures (plain weave, 2/2 twill weave, and honeycomb) to facilitate the laser fenestration. Two commercial devices, Anaconda (Vascutek, Terumo Aortic) and Zenith TX2 (Cook), were selected as controls for comparison against this new design. All the specimens were characterized by morphology, thickness, and water permeability. The results demonstrated that all specimens with a low thickness and water permeability satisfied the requirements for a stent graft material that would be low profile and resistant to endoleaks. The in situ fenestrations were performed on all fabrics utilizing an Excimer laser followed by balloon angioplasty. The fabrics were further observed by light microscopy and scanning electron microscopy. The dimension of the fenestrated apertures was smaller than the balloon’s diameter. The tearing was effectively confined within the corona. The clinical acceptability of this concept deserves additional bench testing and animal experimentation.
Advanced Optimization of Surface Characteristics and Material Removal Rate for Biocompatible Ti6Al4V Using WEDM Process with BBD and NSGA II
Authors: Nagadeepan Anbazhagan , Jayaprakash Govindarajalu , Senthilkumar Vagheesan
Published: July 2023

Machining titanium alloy (Ti6Al4V) used in orthopedic implants via conventional metal cutting processes is challenging due to excessive cutting forces, low surface integrity, and tool wear. To overcome these difficulties and ensure high-quality products, various industries employ wire electrical discharge machining (WEDM) for precise machining of intricate shapes in titanium alloy. The objective is to make WEDM machining parameters as efficient as possible for machining the biocompatible alloy Ti6Al4Vusing Box–Behnken design (BBD) and nondominated sorting genetic algorithm II (NSGA II). A quadratic mathematical model is created to represent the productivity and the quality factor (MRR and surface roughness) in terms of varying input parameters, such as pulse active (Ton) time, pulse inactive (Toff) time, peak amplitude (A) current, and applied servo (V) voltage. The established regression models and related prediction plots provide a reliable approach for predicting how the process variables affect the two responses, namely, MRR and SR. The effects of four process variables on both the responses were examined, and the findings revealed that the pulse duration and voltage have a major influence on the rate at which material is removed (MRR), whereas the pulse duration influences quality (SR). The tradeoff between MRR and SR, when significant process factors are included, emphasizes the need for a reliable multi-objective optimization method. The intelligent metaheuristic optimization method named nondominated sorting genetic algorithm II (NSGA II) was utilized to provide pareto optimum solutions in order to achieve high material removal rate (MRR) and low surface roughness (SR).
Reactive Power Optimization Based on the Application of an Improved Particle Swarm Optimization Algorithm
Authors: Mourtzis Dimitris , Angelopoulos John
Published: July 2023

Climate change, improved energy efficiency, and access to contemporary energy services are among the key topics investigated globally. The effect of these transitions has been amplified by increased digitization and digitalization, as well as the establishment of reliable information and communication infrastructures, resulting in the creation of smart grids (SGs). A crucial aspect in optimizing energy production and distribution is reactive power optimization, which involves the utilization of algorithms such as particle swarm optimization (PSO). However, PSO algorithms can suffer from premature convergence and being trapped in local optima. Therefore, in this research the design and development of an improved PSO algorithm for minimization of power loss in the context of SGs is the key contribution. For digital experimentation and benchmarking of the proposed framework, the IEEE 30-bus standardized model is utilized, which has indicated that an improvement of approximately 11% compared to conventional PSO algorithms can be achieved.
Characterization and Magnetic Properties of Sintered Glass-Ceramics from Dispersed Fly Ash Microspheres
Authors: Fomenko Elena V. , Akimochkina Galina V. , Knyazev Yuriy V. , Semenov Sergey V. , Yumashev Vladimir V. , Solovyov Leonid A. , Anshits Alexander G.
Published: July 2023

The recycling of hazardous industrial waste into high-tech materials with desired properties is of considerable interest since it provides optimal alternatives for its final disposal. Coal fly ash, the major waste generated by coal-fired power plants, contains significant quantities of dispersed microspheres with a diameter smaller than 10 μm, which are anthropogenic atmospheric pollutants PM10. Due to their composition and fine-grained powder morphology, they can be converted into sintered products. In this study, dispersed microspheres from class C fly ash were directly sintered without any additive to form high-strength glass-ceramics with magnetic properties. The optimum processing conditions were achieved at a temperature of 1200 °C, at which samples with a compressive strength of 100.6 MPa were obtained. Sintering reduces the quantity of the glass phase and promotes the formation of larnite, Fe-spinel, ye’elimite, and ternesite. Mössbauer measurements show that the relative concentration of the magnetic phase compared to the paramagnetic one rises almost in order. The sintered sample demonstrates a narrower distribution of the hyperfine magnetic field and a significantly lower value of the coercive field of 25 Oe, which allows proposing such materials as soft magnetic materials. The presented results demonstrate promising industrial applications of hazardous PM10 to minimize solid waste pollution.
Contextual Augmentation Based on Metric-Guided Features for Ocular Axial Length Prediction
Authors: Jeong Yeonwoo , Han Jae-Ho , Oh Jaeryung
Published: July 2023

Ocular axial length (AL) measurement is important in ophthalmology because it should be considered prior to operations, such as strabismus surgery or cataract surgery, and the automation of AL measurement with easily obtained retinal fundus images has been studied. However, the performance of deep learning methods inevitably depends on distribution of the data set used, and the lack of data is an issue that needs to be addressed. In this study, we propose a framework for generating pairs of fundus images and their corresponding ALs to improve the AL inference. The generator’s encoder was trained independently using metric learning based on the AL information. A random vector and zero padding were incorporated into the generator to increase data creation flexibility, after which AL information was inserted as conditional information. We verified the effectiveness of this framework by evaluating the performance of AL inference models after training them on a combined data set comprising privately collected actual data and data generated by the proposed method. Compared to using only the actual data set, the mean absolute error and standard deviation of the proposed method decreased from 10.23 and 2.56 to 3.96 and 0.23, respectively, even with a smaller number of layers in the AL prediction models.
Development of a New Zeta Formula and Its Role in Riemann Hypothesis and Quantum Physics
Authors: Abdelaziz Saadeldin , Shaker Ahmed , Salah Mostafa M.
Published: July 2023

In this study, we investigated a new zeta formula in which the zeta function can be expressed as the sum of an infinite series of delta and cosine functions. Our findings demonstrate that this formula possesses duality characteristics and we established a direct connection between the Riemann hypothesis and this new formula. Additionally, we explored the behavior of energy or particles in quantum physics within the proposed mathematical model framework based on the new formula. Our model provides a valuable understanding of several important physics inquiries, including the collapse of the wave function during measurement and quantum entanglement, as well as the double slits experiment.
Light Pollution Index System Model Based on Markov Random Field
Authors: Fang Liangkun , Wu Zhangjie , Tao Yuan , Gao Jinfeng
Published: July 2023

Light pollution is one of the environmental pollution problems facing the world. The research on the measurement standard of light pollution is not perfect at present. In this paper, we proposed a Markov random field model to determine the light pollution risk level of a site. Firstly, the specific data of 12 indicators of 5 typical cities were collected, and 10-factor indicators were screened using the R-type clustering algorithm. Then, the entropy weight method was used to determine the weight, and the light pollution measurement method of the Markov random field was established. The model was tested by five different data sets, and the test results show that the model is very effective. Three kinds of potential effects were proposed, and the relationship between the factor index and potential effects was established by using the partial least square method. Three possible intervention strategies for solving the problem of light pollution are pointed out: road lighting system planning, increasing vegetation coverage, and building system planning. Finally, a simulated annealing algorithm was used to determine the best intervention strategy, concluding that using strategy 1 in urban neighborhood 2 was the most effective measure, reducing the risk level of light pollution by 17.2%.