bluuebunny/crossref_metadata_2025 huggingface dataset:
Unsteady Cavitation Analysis of the Centrifugal Pump Based on Entropy Production and Pressure Fluctuation
Authors: Si Qiaorui , Deng Fanjie , Lu Yu , Liao Minquan , Yuan Shouqi
Published: November 2023

A numerical method using combined detached-eddy simulation (DES) and a cavitation model considering the rotation effect is used for unsteady cavitation flow field of the centrifugal pump. A closed-type pump test system was established to obtain the pump performance and pressure pulsation characteristics under different flow rates and cavitation condition, which provide boundary conditions and verification of calculations. Based on the calculation results of the unsteady flow field of the centrifugal pump cavitation, the entropy generation analysis of the flow field and an analysis of the pressure fluctuation characteristics were carried out. Then, we tried to reveal the relationship between cavitation and the deterioration of the centrifugal pump performance and the generation of the unstable operation excitation force. The internal energy loss is mainly concentrated in the impeller, volute, and pump cavity area, which accounts for more than 85% of the total entropy generation. The characteristic frequency of a Strouhal number of about 0.333 appears at the volute tongue due to the cavitation flow spread downstream.
Polarizing Topics on Twitter in the 2022 United States Elections
Authors: Katalinić Josip , Dunđer Ivan , Seljan Sanja
Published: November 2023

Politically polarizing issues are a growing concern around the world, creating divisions along ideological lines, which was also confirmed during the 2022 United States midterm elections. The purpose of this study was to explore the relationship between the results of the 2022 U.S. midterm elections and the topics that were covered during the campaign. A dataset consisting of 52,688 tweets in total was created by collecting tweets of senators, representatives and governors who participated in the elections one month before the start of the elections. Using unsupervised machine learning, topic modeling is built on the collected data and visualized to represent topics. Furthermore, supervised machine learning is used to classify tweets to the corresponding political party, whereas sentiment analysis is carried out in order to detect polarity and subjectivity. Tweets from participating politicians, U.S. states and involved parties were found to correlate with polarizing topics. This study hereby explored the relationship between the topics that were creating a divide between Democrats and Republicans during their campaign and the 2022 U.S. midterm election outcomes. This research found that polarizing topics permeated the Twitter (today known as X) campaign, and that all elections were classified as highly subjective. In the Senate and House elections, this classification analysis showed significant misclassification rates of 21.37% and 24.15%, respectively, indicating that Republican tweets often aligned with traditional Democratic narratives.
Science Mapping of Meta-Analysis in Agricultural Science
Authors: Ding Weiting , Li Jialu , Ma Heyang , Wu Yeru , He Hailong
Published: November 2023

As a powerful statistical method, meta-analysis has been applied increasingly in agricultural science with remarkable progress. However, meta-analysis research reports in the agricultural discipline still need to be systematically combed. Scientometrics is often used to quantitatively analyze research on certain themes. In this study, the literature from a 30-year period (1992–2021) was retrieved based on the Web of Science database, and a quantitative analysis was performed using the VOSviewer and CiteSpace visual analysis software packages. The objective of this study was to investigate the current application of meta-analysis in agricultural sciences, the latest research hotspots, and trends, and to identify influential authors, research institutions, countries, articles, and journal sources. Over the past 30 years, the volume of the meta-analysis literature in agriculture has increased rapidly. We identified the top three authors (Sauvant D, Kebreab E, and Huhtanen P), the top three contributing organizations (Chinese Academy of Sciences, National Institute for Agricultural Research, and Northwest A&F University), and top three productive countries (the USA, China, and France). Keyword cluster analysis shows that the meta-analysis research in agricultural sciences falls into four categories: climate change, crop yield, soil, and animal husbandry. Jeffrey (2011) is the most influential and cited research paper, with the highest utilization rate for the Journal of Dairy Science. This paper objectively evaluates the development of meta-analysis in the agricultural sciences using bibliometrics analysis, grasps the development frontier of agricultural research, and provides insights into the future of related research in the agricultural sciences.
Weakly Supervised Learning Approach for Implicit Aspect Extraction
Authors: Mar Aye Aye , Shirai Kiyoaki , Kertkeidkachorn Natthawut
Published: November 2023

Aspect-based sentiment analysis (ABSA) is a process to extract an aspect of a product from a customer review and identify its polarity. Most previous studies of ABSA focused on explicit aspects, but implicit aspects have not yet been the subject of much attention. This paper proposes a novel weakly supervised method for implicit aspect extraction, which is a task to classify a sentence into a pre-defined implicit aspect category. A dataset labeled with implicit aspects is automatically constructed from unlabeled sentences as follows. First, explicit sentences are obtained by extracting explicit aspects from unlabeled sentences, while sentences that do not contain explicit aspects are preserved as candidates of implicit sentences. Second, clustering is performed to merge the explicit and implicit sentences that share the same aspect. Third, the aspect of the explicit sentence is assigned to the implicit sentences in the same cluster as the implicit aspect label. Then, the BERT model is fine-tuned for implicit aspect extraction using the constructed dataset. The results of the experiments show that our method achieves 82% and 84% accuracy for mobile phone and PC reviews, respectively, which are 20 and 21 percentage points higher than the baseline.
Research Progress on the Regulation of Autophagy and Apoptosis in Insects by Sterol Hormone 20-Hydroxyecdysone
Authors: Lin Luobin , Li Huaqin , Zheng Qinzhou , Hu Jiaxuan , Wu Wenmei
Published: November 2023

20E (20-Hydroxyecdysone) is a central steroid hormone that orchestrates developmental changes and metamorphosis in arthropods. While its molecular mechanisms have been recognized for some time, detailed elucidation has primarily emerged in the past decade. PCD (Programmed cell death), including apoptosis, necrosis, efferocytosis, pyroptosis, ferroptosis, and autophagy, plays a crucial role in regulated cell elimination, which is vital for cells’ development and tissue homeostasis. This review summarizes recent findings on 20E signaling regulated autophagy and apoptosis in insects, including Drosophila melanogaster, Bombyx mori, Helicoverpa armigera, and other species. Firstly, we comprehensively explore the biosynthesis of the sterol hormone 20E and its subsequent signal transduction in various species. Then, we focus on the involvement of 20E in regulating autophagy and apoptosis, elucidating its roles in both developmental contexts and bacterial infection scenarios. Furthermore, our discussion unfolds as a panoramic exposition, where we delve into the fundamental questions with our findings, anchoring them within the grander scheme of our study in insects. Deepening the understanding of 20E-autophagy/apoptosis axis not only underscores the intricate tapestry of endocrine networks, but also offers fresh perspectives on the adaptive mechanisms that have evolved in the face of environmental challenges.
Strategy Comparison of Endoscopic Ultrasound-Guided Gallbladder Drainage to Percutaneous Transhepatic Gallbladder Drainage, Following Failed Emergent Endoscopic Transpapillary Gallbladder Drainage
Authors: Sagami Ryota , Mizukami Kazuhiro , Sato Takao , Nishikiori Hidefumi , Murakami Kazunari
Published: November 2023

Endoscopic transpapillary gallbladder drainage (ETGBD) is recommended for patients with acute cholecystitis at high risk for surgery/percutaneous transhepatic gallbladder drainage (PTGBD). Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) has higher success and mortality rates than ETGBD. Optimal endoscopic drainage remains controversial. Patients with moderate/severe acute cholecystitis and high risk for surgery/PTGBD who underwent ETGBD were enrolled. In the new-ETGBD (N-ETGBD)/traditional-ETGBD (T-ETGBD) strategy, patients in whom the initial ETGBD failed underwent rescue-EUS-GBD in the same endoscopic session/rescue-PTGBD, respectively. Therapeutic outcomes were compared. Patients who could not undergo rescue-EUS-GBD/PTGBD owing to poor general conditions received conservative treatment. Technical success was defined as successful ETGBD or successful rescue-EUS-GBD/PTGBD. Forty-one/forty patients were enrolled in the N-ETGBD/T-ETGBD groups, respectively. The N-ETGBD group had a higher, though non-significant, technical success rate compared to the T-ETGBD group (97.6 vs. 90.0%, p = 0.157). The endoscopic technical success rate was significantly higher in the N-ETGBD than in the T-ETGBD group (97.6 vs. 82.5%, p = 0.023). The clinical success/adverse event rates were similar between both groups. The hospitalization duration was significantly shorter in the N-ETGBD than in the T-ETGBD group (6.6 ± 3.9 vs. 10.1 ± 6.4 days, p < 0.001). ETGBD with EUS-GBD as a rescue backup may be an ideal hybrid drainage for emergency endoscopic gallbladder drainage in high-risk surgical patients.
Osseodensification: An Alternative to Conventional Osteotomy in Implant Site Preparation: A Systematic Review
Authors: Fontes Pereira João , Costa Rosana , Nunes Vasques Miguel , Salazar Filomena , Mendes José Manuel , Infante da Câmara Marco
Published: November 2023

Osseodensification is an innovative method of preparing the implant osteotomy using drills that promote bone self-compaction. The main objective of this technique is to promote peri-implant bone densification and compaction of autologous bone and to increase the primary stability of the implant due to the viscoelastic characteristics of the alveolar bone using Densah® burs in a counterclockwise direction at a speed of 800 to 1500 rpm. The objective of this review is the analysis of the scientific literature regarding the applicability of the osseodensification technique in oral implantology. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were used and registered at PROSPERO. The search strategy included electronic databases from 2016 to 2023 and was performed by two independent reviewers. The results demonstrate the advantage of the osseodensification technique in relation to conventional drilling, allowing an increase in the bone density and primary stability of the implant, bone density, and bone–implant contact. The osseodensification technique can be applied in different clinical situations: sub-antral bone grafts, narrow alveolar bone crests, low-density bone areas, and immediate implant placement in post-extraction sockets.
Underwater Implosion and Energy Mitigation of Hybrid Glass-Carbon Composite Shells
Authors: Ngwa Akongnwi Nfor , Chaudhary Birendra , Matos Helio , Shukla Arun
Published: November 2023

Experiments were conducted to investigate the dynamic buckling behavior of underwater hybrid composite tubes. The study focused on roll-wrapped hybrid layered glass-carbon fiber epoxy composite shells with a six-layer quasi-isotropic layup configuration. In addition to control specimens consisting of fully glass fiber-reinforced polymer and carbon fiber-reinforced polymer, four different hybrid layup patterns were examined. These specimens fitted with custom endcaps were placed inside a 7-kiloliter pressure vessel and subjected to increasing hydrostatic pressure until dynamic implosion occurred. High-speed cameras captured the failure event, and the resulting images were analyzed using Digital Image Correlation (DIC) techniques to obtain full-field displacement data. Additionally, tourmaline pressure transducers positioned around the specimens recorded local dynamic pressure histories. The results revealed that the contribution of each ply location varied in the overall failure behavior of the structures. The thickness of the internal plies played a dominant role in enhancing the structural performance, while the stiffness of the outer plies greatly influenced the bending stiffness. The energy released during the collapse was highly dependent on the failure mechanism of the internal plies. Specifically, for the considered geometries, tubes with glass fiber internal plies exhibited significantly lower energy emissions compared to carbon fiber inner plies.
Impact of Correction Target Selection on Long-Term Spectral Nudging in Luzon Strait and Its Adjacent Regions
Authors: Fu Xiachuan , He Zhongjie , Zhao Yueqi , Jiang Xuyu , Wang Mengyao
Published: November 2023

Previous studies have pointed out that spectral nudging is still insufficient in improving the long-term simulation ability of numerical models. In response to this problem, this study started with the Luzon Strait and its adjacent areas and discussed the influence of the selection of correction targets on its long-term spectral nudging. We established two sets of numerical experiments with the same parameter configuration except for the correction target: one was the monthly climatological target, and the other was the monthly real-time. The results showed that, compared with the climatology, the real-time target improved the consistency with the observations in large-scale variability on the premise of ensuring the correction of the climatological bias of the model. Further verification of the real-time scheme better simulated the meso- and small-scale characteristics, especially more accurately reproducing the position, intensity, and movement trend of eddies when the Kuroshio intrusion event occurred. Multi-scale energy analysis revealed the significance of adjusting large-scale potential energy to improve the overall simulation ability. The premise is that the correction target needs to fully contain these effective large-scale signals and non-stationary features, and then introduce them into the numerical integration of the regional model through appropriate band-pass filter parameter settings, driving a more reasonable large-scale background state thereby.
The Early Endocytosis Gene PAL1 Contributes to Stress Tolerance and Hyphal Formation in Candida albicans
Authors: Yu Miranda , Ma Dakota , Eszterhas Susan , Rollenhagen Christiane , Lee Samuel
Published: November 2023

The endocytic and secretory pathways of the fungal pathogen Candida albicans are fundamental to various key cellular processes such as cell growth, cell wall integrity, protein secretion, hyphal formation, and pathogenesis. Our previous studies focused on several candidate genes involved in early endocytosis, including ENT2 and END3, that play crucial roles in such processes. However, much remains to be discovered about other endocytosis-related genes and their contributions toward Candida albicans secretion and virulence. In this study, we examined the functions of the early endocytosis gene PAL1 using a reverse genetics approach based on CRISPR-Cas9-mediated gene deletion. Saccharomyces cerevisiae Pal1 is a protein in the early coat complex involved in clathrin-mediated endocytosis that is later internalized with the coat. The C. albicans pal1Δ/Δ null mutant demonstrated increased resistance to the antifungal agent caspofungin and the cell wall stressor Congo Red. In contrast, the null mutant was more sensitive to the antifungal drug fluconazole and low concentrations of SDS than the wild type (WT) and the re-integrant (KI). While pal1Δ/Δ can form hyphae and a biofilm, under some hyphal-inducing conditions, it was less able to demonstrate filamentous growth when compared to the WT and KI. The pal1Δ/Δ null mutant had no defect in clathrin-mediated endocytosis, and there were no changes in virulence-related processes compared to controls. Our results suggest that PAL1 has a role in susceptibility to antifungal agents, cell wall integrity, and membrane stability related to early endocytosis.
Towards a High-Affinity Peptidomimetic Targeting Proliferating Cell Nuclear Antigen from Aspergillus fumigatus
Authors: Vandborg Bethiney C. , Horsfall Aimee J. , Pederick Jordan L. , Abell Andrew D. , Bruning John B.
Published: November 2023

Invasive fungal infections (IFIs) are prevalent in immunocompromised patients. Due to alarming levels of increasing resistance in clinical settings, new drugs targeting the major fungal pathogen Aspergillus fumigatus are required. Attractive drug targets are those involved in essential processes like DNA replication, such as proliferating cell nuclear antigens (PCNAs). PCNA has been previously studied in cancer research and presents a viable target for antifungals. Human PCNA interacts with the p21 protein, outcompeting binding proteins to halt DNA replication. The affinity of p21 for hPCNA has been shown to outcompete other associating proteins, presenting an attractive scaffold for peptidomimetic design. p21 has no A. fumigatus homolog to our knowledge, yet our group has previously demonstrated that human p21 can interact with A. fumigatus PCNA (afumPCNA). This suggests that a p21-based inhibitor could be designed to outcompete the native binding partners of afumPCNA to inhibit fungal growth. Here, we present an investigation of extensive structure–activity relationships between designed p21-based peptides and afumPCNA and the first crystal structure of a p21 peptide bound to afumPCNA, demonstrating that the A. fumigatus replication model uses a PIP-box sequence as the method for binding to afumPCNA. These results inform the new optimized secondary structure design of a potential peptidomimetic inhibitor of afumPCNA.
Credit Access and the Firm–Government Connection: Is There Any Link?
Authors: Phan Trang Thu , Ta Linh Nhat , Pham Trang Tran Minh , Pham Dung Thi Thuy
Published: November 2023

Access to credit for businesses is an unresolved issue, especially in developing countries and transition economies. There has been a lot of research exploring factors affecting firms’ credit accessibility. Particularly, factors related to borrowers and lenders are always placed under consideration. However, besides those factors, institutional elements could also play an important role in guiding companies’ operations. In countries where the economy lacks transparency and low-level development is limited, informal institutional factors can have potential impacts. In this paper, we focus on exploring the relationship between firm–government links and credit access, thereby offering managerial implications through utilizing cross-sectional data sets at the firm level, with an initial sample of 26,849 observations from 38 countries at different levels of development around the world. The results show a positive correlation of firm–government connection with credit access. Moreover, this relationship may vary depending on the market in which the business primarily operates. Specifically, firms working internationally are less influenced by links with governments and tend to rely more on their own characteristics and conditions.
Detecting Fraudulent Transactions Using Stacked Autoencoder Kernel ELM Optimized by the Dandelion Algorithm
Authors: El Hlouli Fatima Zohra , Riffi Jamal , Sayyouri Mhamed , Mahraz Mohamed Adnane , Yahyaouy Ali , El Fazazy Khalid , Tairi Hamid
Published: November 2023

The risk of fraudulent activity has significantly increased with the rise in digital payments. To resolve this issue there is a need for reliable real-time fraud detection technologies. This research introduced an innovative method called stacked autoencoder kernel extreme learning machine optimized by the dandelion algorithm (S-AEKELM-DA) to detect fraudulent transactions. The primary objective was to enhance the kernel extreme learning machine (KELM) performance by integrating the dandelion technique into a stacked autoencoder kernel ELM architecture. This study aimed to improve the overall effectiveness of the proposed method in fraud detection by optimizing the regularization parameter (c) and the kernel parameter (σ). To evaluate the S-AEKELM-DA approach; simulations and experiments were conducted using four credit card datasets. The results demonstrated remarkable performance, with our method achieving high accuracy, recall, precision, and F1-score in real time for detecting fraudulent transactions. These findings highlight the effectiveness and reliability of the suggested approach. By incorporating the dandelion algorithm into the S-AEKELM framework, this research advances fraud detection capabilities, thus ensuring the security of digital transactions.
The Road to India’s Renewable Energy Transition Must Pass through Crowded Lands
Authors: Kiesecker Joseph M. , Nagaraju Shivaprakash K. , Oakleaf James R. , Ortiz Anthony , Lavista Ferres Juan , Robinson Caleb , Krishnaswamy Srinivas , Mehta Raman , Dodhia Rahul , Evans Jeffrey S. , Heiner Michael , Priyadarshini Pratiti , Chandran Pooja , Sochi Kei
Published: November 2023

The significance of renewable energy in achieving necessary reductions in emissions to limit global warming to 1.5 degrees Celsius is widely acknowledged. However, there is growing concern over the allocation of land for constructing the required new infrastructure. Nowhere is this conflict more apparent than in India, where renewable energy targets are ambitious and land use conflicts are already significant. India intends to increase renewable energy to 500 GW by 2030. This would require an additional 42 GW of renewable energy to be installed every year. Although renewable energy can provide the solution to both India’s growing need for cheap energy and climate change mitigation, the sustainable future of renewable energy deployment is far from simple due to its associated land use impacts and socio-ecological risk. While others have highlighted challenges to India’s renewable energy targets, here we focus on the land use change issues that will need to be addressed for India to meet its targets. We introduce a series of recommendations and highlight how these could contribute to mainstreaming land values and facilitate the implementation of India’s 2030 renewable energy targets. These recommendations include suggested planning approaches that would guide the development of standard siting guidelines, identification of preferential “go-to” areas for renewable energy, and the development of tools that allow access to data and information to site renewable right. Policy recommendations highlight utilizing converted lands and existing built infrastructure for renewable energy development, and adapting existing policies so they address land use impacts.
One-Pot Formation of Pairing Proto-RNA Nucleotides and Their Supramolecular Assemblies
Authors: Roche Tyler P. , Nedumpurath Pranav J. , Karunakaran Suneesh C. , Schuster Gary B. , Hud Nicholas V.
Published: November 2023

Most contemporary theories for the chemical origins of life include the prebiotic synthesis of informational polymers, including strong interpretations of the RNA World hypothesis. Existing challenges to the prebiotic emergence of RNA have encouraged exploration of the possibility that RNA was preceded by an ancestral informational polymer, or proto-RNA, that formed more easily on the early Earth. We have proposed that the proto-nucleobases of proto-RNA would have readily formed glycosides with ribose and that these proto-nucleosides would have formed base pairs as monomers in aqueous solution, two properties not exhibited by the extant nucleosides or nucleotides. Here we demonstrate that putative proto-nucleotides of the model proto-nucleobases barbituric acid and melamine can be formed in the same one-pot reaction with ribose-5-phosphate. Additionally, the proto-nucleotides formed in these reactions spontaneously form assemblies that are consistent with the presence of Watson–Crick-like base pairs. Together, these results provide further support for the possibility that heterocycles closely related to the extant bases of RNA facilitated the prebiotic emergence of RNA-like molecules, which were eventually replaced by RNA over the course of chemical and biological evolution.
Simulation of Microscopic Fracture Behavior in Nanocomposite Ceramic Tool Materials
Authors: Zhou Tingting , Meng Lingpeng , Yi Mingdong , Xu Chonghai
Published: November 2023

In this paper, the microstructures of nanocomposite ceramic tool materials are represented through Voronoi tessellation. A cohesive element model is established to perform the crack propagation simulation by introducing cohesive elements with fracture criteria into microstructure models. Both intergranular and transgranular cracking are considered in this work. The influences of nanoparticle size, microstructure type, nanoparticle volume content and interface fracture energy are analyzed, respectively. The simulation results show that the nanoparticles have changed the fracture pattern from intergranular mode in single-phase materials to intergranular–transgranular–mixed mode. It is mainly the nanoparticles along grain boundaries that have an impact on the fracture pattern change in nanocomposite ceramic tool materials. Microstructures with smaller nanoparticles, in which there are more nanoparticles dispersed along matrix grain boundaries, have higher fracture toughness. Microstructures with a nanoparticle volume content of 15% have the most obvious transgranular fracture phenomenon and the highest critical fracture energy release rate. A strong interface is useful for enhancing the fracture toughness of nanocomposite ceramic tool materials.
A Design Method on Durable Asphalt Pavement of Flexible Base on Anti-Rutting Performance and Its Application
Authors: Li Limin , Guo Enping , Lin Yuliang , He Zhaoyi
Published: November 2023

To solve the durability of flexible base asphalt pavement, especially its anti-rutting problem, a design method on durable asphalt pavement of flexible base on anti-rutting performance was put forward in the paper, based on many experiments and calculations. Firstly, a method that asphalt could be selected according to penetration and the anti-rutting factor of its base asphalt was found, which solved the problem of the asphalt selection of the flexible base asphalt mixture design. Meanwhile, a method of skeleton-density structure gradation design was proposed based on the fractal void ratio of coarse aggregate, fractal volume of fine aggregate in coarse aggregate, penetration, fractal dimension of gradation particle size, and rutting tests, which effectively solved in advance the rutting and fatigue performance of flexible base asphalt mixtures. Then, on the basis of the fatigue damage, a calculation method of fatigue life was suggested, which solved the problem that the fatigue damage of asphalt mixtures rarely considered the combined effects of creep damage and fatigue damage. In addition, a calculation method of rutting was formulated based on vehicle dynamic load and ANSYS 16.0 software. Lastly, the feasibility of the design method on durable asphalt pavement of flexible base on anti-rutting performance was verified combining with the real engineering of a supporting project and several numerical calculations and tests.
A Review of Abdominal Meshes for Hernia Repair—Current Status and Emerging Solutions
Authors: Najm Alfred , Niculescu Adelina-Gabriela , Gaspar Bogdan Severus , Grumezescu Alexandru Mihai , Beuran Mircea
Published: November 2023

Abdominal hernias are common issues in the clinical setting, burdening millions of patients worldwide. Associated with pain, decreased quality of life, and severe potential complications, abdominal wall hernias should be treated as soon as possible. Whether an open repair or laparoscopic surgical approach is tackled, mesh reinforcement is generally required to ensure a durable hernia repair. Over the years, numerous mesh products have been made available on the market and in clinical settings, yet each of the currently used meshes presents certain limitations that reflect on treatment outcomes. Thus, mesh development is still ongoing, and emerging solutions have reached various testing stages. In this regard, this paper aims to establish an up-to-date framework on abdominal meshes, briefly overviewing currently available solutions for hernia repair and discussing in detail the most recent advances in the field. Particularly, there are presented the developments in lightweight materials, meshes with improved attachment, antimicrobial fabrics, composite and hybrid textiles, and performant mesh designs, followed by a systematic review of recently completed clinical trials.
The Mutual Influence of Thermal Contact Conductivity and Convective Cooling on the Temperature Field in a Tribosystem with a Functionally Graded Strip
Authors: Yevtushenko Aleksander , Topczewska Katarzyna , Zamojski Przemysław
Published: November 2023

An analytical model to find the temperature field that has been developed for friction systems consists of a strip and semi-space. The strip is made of a two-component functionally graded material (FGM) with an exponentially changing coefficient of thermal conductivity. In contrast, the material of the semi-space is homogeneous. An appropriate boundary-value problem of heat conduction with constant specific friction power was formulated and solved using the Laplace integral transform method. The model takes into consideration the imperfect thermal friction contact between the strip and the semi-space, and also the convective cooling on the exposed surface of the strip. The appropriate asymptotic solutions to this problem for low and high values of Fourier number were obtained. It is shown how the determined exact solution can be generalized using Duhamel’s formula for the case of a linearly reduction in time-specific friction power (a braking process with constant deceleration). Numerical analysis for selected materials of the friction pair was carried out in terms of examining the mutual impact on the temperature of the two Biot numbers, characterizing the intensity of the thermal contact conductivity and convective heat exchange on the exposed surface of the strip. The obtained results can be used to predict the temperature of friction systems containing elements made of FGM. In particular, such systems include modern disc braking systems.
Jointing Achievement and Performance Evaluation of Bogie Crossmember Ring Joint Welded via Inertia Friction Welding
Authors: Qin Feng , Zhang Xinmeng , Zhang Chunbo , Wu Yanquan , Liang Wu , Li Rui , Zhou Jun
Published: November 2023

As a major load-bearing component of trains, the weld quality of the bogie beam is critical to the safety of railway operations. This study specifically investigates the inertia friction welding process of S355 bogie crosshead tubes, with the aim of improving the weld quality and achieving one-time formation of the crosshead tube and tube seat. The microstructural features and mechanical properties of S355 inertia-welded joints were also compared with the base metal. Research indicates that inertia friction welds have no visible defects, and that the microstructure of the welding seam (WS) consists of granular bainite, acicular ferrite and little pearlite. The thermo-mechanically affected zone (TMAZ) consists of granular bainite bands and ferrite + pearlite bands. The hot work strengthening mechanism of inertia friction welding results in a higher level of hardness for both WS and TMAZ. The tensile property of the welded joints can be compared to the base metal. The yield strength, tensile strength and elongation of the welded joints, respectively, reach 87.5%, 100% and 79.5% of S355. However, the impact toughness of the welds at room temperature is lower than that of the base material, particularly in the TMAZ zone. Conversely, in an environment with a temperature of −40 °C, WS’s impact toughness surpasses that of the parent material.
Influence of the Phase Composition of Titanium Alloys on Cell Adhesion and Surface Colonization
Authors: Straumal Boris B. , Anisimova Natalia Yu. , Kiselevskiy Mikhail V. , Novruzov Keryam M. , Korneva Anna , Gornakova Alena S. , Kilmametov Askar R. , Sommadossi Silvana , Davdian Gregory
Published: November 2023

The pivotal role of metal implants within the host’s body following reconstructive surgery hinges primarily on the initial phase of the process: the adhesion of host cells to the implant’s surface and the subsequent colonization by these cells. Notably, titanium alloys represent a significant class of materials used for crafting metal implants. This study, however, marks the first investigation into how the phase composition of titanium alloys, encompassing the volume fractions of the α, β, and ω phases, influences cell adhesion to the implant’s surface. Moreover, the research delves into the examination of induced hemolysis and cytotoxicity. To manipulate the phase composition of titanium alloys, various parameters were altered, including the chemical composition of titanium alloys with iron and niobium, annealing temperature, and high-pressure torsion parameters. By systematically adjusting these experimental parameters, we were able to discern the distinct impact of phase composition. As a result, the study unveiled that the colonization of the surfaces of the examined Ti–Nb and Ti–Fe alloys by human multipotent mesenchymal stromal cells exhibits an upward trend with the increasing proportion of the ω phase, concurrently accompanied by a decrease in the α and β phases. These findings signify a new avenue for advancing Ti-based alloys for both permanent implants and temporary fixtures, capitalizing on the ability to regulate the volume fractions of the α, β, and ω phases. Furthermore, the promising characteristics of the ω phase suggest the potential emergence of a third generation of biocompatible Ti alloys, the ω-based materials, following the first-generation α-Ti alloys and second-generation β alloys.
Effect of Shot Peening on the Low-Cycle Fatigue Behavior of an AA2519-T62 Friction-Stir-Welded Butt Joint
Authors: Kosturek Robert , Ślęzak Tomasz , Torzewski Janusz , Bucior Magdalena , Zielecki Władysław , Śnieżek Lucjan , Sęp Jarosław
Published: November 2023

In this investigation, an AA2519-T62 FSW butt joint was subjected to shot peening with an air pressure of p = 0.6 MPa, a processing time of t = 10 min (per side), and a steel ball diameter of dk = 1.5 mm. In order to evaluate the impact of shot peening on the low-cycle behavior, the samples were tested with coefficient R = 0.1 at total strain amplitudes of 0.35%, 0.4%, and 0.5%. The shot-peened welds are characterized by a higher value of stress amplitude, a lower value of plastic strain amplitude, and their fatigue life increased slightly. The cyclic strength coefficient and the cyclic strain hardening exponent were reduced by 45% and 55%, respectively, as the result of the surface layer hardening. The shot peening process had no noticeable effect on the character of crack initiation and propagation. Almost in all cases, the cracking started in the area under the weld face, located close to the boundary between the thermo-mechanically affected zone and the stir zone at the advancing side. Only at the heaviest loadings (εac = 0.5%) were cracks initiated in the heat-affected zone at the retreating side. Despite the introduction of small cracks in the stir zone, their presence did not affect the decohesion character of the welded joint. Overall, it was observed that there is a minimal, positive impact of shot peening on the properties of the investigated joints.
High-Grade Ferronickel Concentrates Prepared from Laterite Nickel Ore by a Carbothermal Reduction and Magnetic Separation Method
Authors: Zhang Jingzhe , Cao Chang , Xue Zhengliang , Li Faliang , Li Shaoping , Duan Hongjuan , Zhang Haijun
Published: November 2023

Nickel is widely used in industrial processes and plays a crucial role in many applications. However, most of the nickel resource mainly exists as nickel oxide in laterite nickel ore with complex composition, resulting in difficulty in upgrading the nickel content using physical separation methods. In this study, high-grade ferronickel concentrates were obtained through a carbothermal reduction and magnetic separation using laterite nickel ore and anthracite as raw materials. The effects of different types of additives (CaF2, Na2SO4, and H3BO3), carbon ratio (the molar ratio of oxygen atoms in the laterite nickel ore to carbon atoms in anthracite), and grinding time on the recoveries and grades of ferronickel concentrates were experimentally investigated, along with the microstructure and chemical composition of the products. CaF2 was proved to be the primary active additive in the aggregation and growth of the ferronickel particles and the improvement of the grade of the product. Under the optimal conditions of CaF2 addition of 9.85 wt%, carbon ratio of 1.4, and grinding time of 240 s, high-grade magnetically separable ferronickel concentrate with nickel grade 8.93 wt% and iron grade 63.96 wt% was successfully prepared. This work presents a practical method for the highly efficient recovery and utilization of iron and nickel from low-grade laterite nickel ore, contributing to the development of strategies for the sustainable extraction and utilization of nickel resources.
The Effects of Hybrid Steel/Basalt Fibers on the Durability of Concrete Pavement against Freeze–Thaw Cycles
Authors: Yu Jianqiao , Yi Zijing , Zhang Zhigang , Liu Dawei , Ran Junxin
Published: November 2023

Freeze–thaw (F-T) is one of the principal perils afflicting concrete pavements. A remedial strategy used during construction encompasses the integration of hybrid fibers into the concrete matrix. An extant research gap persists in elucidating the damage mechanism inherent in hybrid steel fiber (SF)- and basalt fiber (BF)-reinforced concrete subjected to F-T conditions. This paper empirically investigated the durability performance of hybrid fiber-reinforced concrete (HFRC) subjected to F-T cycles. The impact of SF/BF hybridization on mass loss, abrasion resistance, compressive strength, flexural strength, damaged layer thickness, and the relative dynamic modulus of elasticity (RDME) was examined. The damage mechanism was explored using micro-hardness and SEM analysis. The results indicate that incorporating hybrid SF/BF effectively enhances the F-T resistance of concrete and prolongs the service life of concrete pavement. The mechanisms underlying these trends can be traced back to robust bonding at the fiber/matrix interface. Randomly dispersed SFs and BFs contribute to forming a three-dimensional spatial structure within the concrete matrix, suppressing the expansion of internal cracks caused by accumulated hydrostatic pressure during the F-T cycle. This research outcome establishes a theoretical foundation for the application of HFRC to concrete pavements in cold regions.
Optimization of Functional Toothpaste Formulation Containing Nano-Hydroxyapatite and Birch Extract for Daily Oral Care
Authors: Florea Alexandra-Diana , Dobrota Cristina Teodora , Carpa Rahela , Racz Csaba-Pal , Tomoaia Gheorghe , Mocanu Aurora , Avram Alexandra , Soritau Olga , Pop Lucian Cristian , Tomoaia-Cotisel Maria
Published: November 2023

This research work aims to develop functional toothpastes with combined enamel remineralization and antibacterial effects using nano-hydroxyapatites (nHAPs) and birch extract. Eleven toothpastes (notated as P1–P11) were designed featuring different concentrations of birch extract and a constant concentration of pure nHAPs or substituted nHAPs (HAP-5%Zn, HAP-0.23%Mg-3.9%Zn-2%Si-10%Sr, and HAP-2.5%Mg-2.9%Si-1.34%Zn). In vitro assessments involved treating artificially demineralized enamel slices and analyzing surface repair and remineralization using Atomic Force Microscopy (AFM). The Agar Disk Diffusion method was used to measure antibacterial activity against Enterococcus faecalis, Escherichia coli, Porphyromonas gingivalis, Streptococcus mutans, and Staphylococcus aureus. Topographic images of enamel structure and surface roughness, as well as the ability of nHAP nanoparticles to form self-assembled layers, revealed excellent restorative properties of the tested toothpastes, with enamel nanostructure normalization occurring as soon as 10 days after treatment. The outcomes highlighted enamel morphology improvements due to the toothpaste treatment also having various efficacious antibacterial effects. Promising results were obtained using P5 toothpaste, containing HAP-5%Zn (3.4%) and birch extract (1.3%), indicating notable remineralization and good antibacterial properties. This study represents a significant advancement in oral care by introducing toothpaste formulations that simultaneously promote enamel health through effective remineralization and bacterial inhibition.
Wear of Abrasive Tools during CMC Machining
Authors: Girot Mata Franck Andrés , Renderos Cartagena Mario Alfredo , Alonso Pinillos Unai , Aramburu Borja Izquierdo
Published: November 2023

Machining CMCs under productivity conditions while limiting tool wear and material damage is a challenge for applications such as jet aircraft engines and industrial turbines. This contribution focused on developing a method to characterize the wear of abrasive tools based on fractal dimensions. This solution allows characterization of the state of the tool after each machining and identification of the type of damage to the tool (regular wear of the diamond grains, cleavage, or breakage) and its influence on the cutting forces, in addition to damage to the machined material and the quality of the machined surface. Thus, the chipped area and the maximum chipping are directly associated with the fractal dimension of the tool surface and the metal removal rate of the process. The quality of the surface (Sa, Sz, and Sq) is associated with the fractal dimension of the surface of the tool characterizing the state of the grinding wheel and the radial depth of cut ae characterizing the engagement of the tool in the CMC material. Moreover, the results also demonstrated that the use of an abrasive tool associated with cutting conditions close to milling and not grinding is a viable solution.
Statistical Inference for Partially Linear Varying Coefficient Spatial Autoregressive Panel Data Model
Authors: Feng Sanying , Tong Tiejun , Chiu Sung Nok
Published: November 2023

This paper studies the estimation and inference of a partially linear varying coefficient spatial autoregressive panel data model with fixed effects. By means of the basis function approximations and the instrumental variable methods, we propose a two-stage least squares estimation procedure to estimate the unknown parametric and nonparametric components, and meanwhile study the asymptotic properties of the proposed estimators. Together with an empirical log-likelihood ratio function for the regression parameters, which follows an asymptotic chi-square distribution under some regularity conditions, we can further construct accurate confidence regions for the unknown parameters. Simulation studies show that the finite sample performance of the proposed methods are satisfactory in a wide range of settings. Lastly, when applied to the public capital data, our proposed model can also better reflect the changing characteristics of the US economy compared to the parametric panel data models.
Hidden Dynamics of a New Jerk-like System with a Smooth Memristor and Applications in Image Encryption
Authors: Wang Zuolei , Zhuang Lizhou , Yu Jianjiang , Jiang Haibo , Xu Wanjiang , Shi Xuerong
Published: November 2023

Considering the dynamic characteristics of memristors, a new Jerk-like system without an equilibrium point is addressed based on a Jerk-like system, and the hidden dynamics are investigated. When changing system parameter b and fixing other parameters, the proposed system shows various hidden attractors, such as a hidden chaotic attractor (b = 5), a hidden period-1 attractor (b = 3.2), and a hidden period-2 attractor (b = 4). Furthermore, bifurcation analysis suggests that not only parameter b, but also the initial conditions of the system, have an effect on the hidden dynamics of the discussed system. The coexistence of various hidden attractors is explored and different coexistences of hidden attractors can be found for suitable system parameters. Offset boosting of different hidden attractors is discussed. It is observed that offset boosting can occur for hidden chaotic attractor, period-1 attractor, and period-2 attractor, but not for period-3 attractor and period-4 attractor. The antimonotonicity of the proposed system is debated and a full Feigenbaum remerging tree can be detected when system parameters a or b change within a certain range. On account of the complicated dynamics of the proposed system, an image encryption scheme is designed, and its encryption effectiveness is analyzed via simulation and comparison.
Quasi-Statistical Schouten–van Kampen Connections on the Tangent Bundle
Authors: Druta-Romaniuc Simona-Luiza
Published: November 2023

We determine the general natural metrics G on the total space TM of the tangent bundle of a Riemannian manifold (M,g) such that the Schouten–van Kampen connection ∇¯ associated to the Levi-Civita connection of G is (quasi-)statistical. We prove that the base manifold must be a space form and in particular, when G is a natural diagonal metric, (M,g) must be locally flat. We prove that there exist one family of natural diagonal metrics and two families of proper general natural metrics such that (TM,∇¯,G) is a statistical manifold and one family of proper general natural metrics such that (TM∖{0},∇¯,G) is a quasi-statistical manifold.
On the Space of G-Permutation Degree of Some Classes of Topological Spaces
Authors: Kočinac Ljubiša D. R. , Mukhamadiev Farkhod G. , Sadullaev Anvar K.
Published: November 2023

In this paper, we study the space of G-permutation degree of some classes of topological spaces and the properties of the functor SPGn of G-permutation degree. In particular, we prove: (a) If a topological space X is developable, then so is SPGnX; (b) If X is a Moore space, then so is SPGnX; (c) If a topological space X is an M1-space, then so is SPGnX; (d) If a topological space X is an M2-space, then so is SPGnX.
Analysis of Decision-Making in a Green Supply Chain under Different Carbon Tax Policies
Authors: Deng Liurui , Tan Jie , Dai Jiawu
Published: November 2023

With the growing severity of global environmental issues, the international community has reached a consensus on the importance of reducing and controlling carbon emissions. As a result, an increasing number of consumers are opting to purchase green products in order to reduce the emission of greenhouse gases. This trend has prompted supply-chain enterprises to invest in green innovation. Simultaneously, carbon tax policies have gained significant attention from governments worldwide due to their dual role as environmental laws and fiscal-policy tools. Considering consumers’ preference for green products and the risk of R&D failure associated with them, this study focuses on the effects on emissions reductions and profits associated with different carbon tax policies for a green supply chain consisting of a manufacturer and a retailer. The results reveal that (1) increases in the carbon tax per unit of product motivate the manufacturer to increase R&D efforts; (2) wholesale and retail prices follow a pattern of initial increase and subsequent decrease as the carbon tax per unit of product rises; (3) higher carbon taxes per unit of product generally lead to lower manufacturer profits, while both carbon emissions and retailer profits can increase with a per-unit carbon tax under certain circumstances; and (4) the increase in the proportion of the population with green preferences can yield long-term benefits for both the retailer and the manufacturer, yielding an inverted U-shaped relationship with carbon emissions.