bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-Forming of Carbon Fibre-Reinforced PEEK Thermoplastic Tubular Structures
Authors: Li Mengyuan , Stokes-Griffin Chris , Compston Paul
Published: August 2024

This paper presents a post-forming technique utilising both induction heating and rotary draw bending (RDB) for carbon fibre-reinforced polyetherentherketone (CF/PEEK) tubular structures. Existing post-forming techniques are unable to form CF/PEEK tubes due to the lack of a suitable mandrel material to provide internal support to the tube while withstanding high heat from melting the PEEK matrix during forming. This is addressed by using a steel spring mandrel in the tube induction heating process. In this study, four sets of [±60°]4 CF/PEEK tubes were formed using an induction heater-incorporated RDB setup into 45°, 90°, 135°, and 180° bends with a bending ratio of 2. Optical characterisation was performed to analyse tube fibre angle changes. A post-forming fibre angle prediction model previously derived for CF/polyamide 6 tubes was validated for its application in predicting fibre angle changes for CF/PEEK tubes by comparing the prediction with the characterised results.
From Germ Cells to Implantation: The Role of Extracellular Vesicles
Authors: Fazzio Anna , Caponnetto Angela , Ferrara Carmen , Purrello Michele , Di Pietro Cinzia , Battaglia Rosalia
Published: August 2024

Extracellular vesicles represent a large heterogeneous class of near and long-distance intercellular communication mediators, released by both prokaryotic and eukaryotic cells. Specifically, the scientific community has shown growing interest in exosomes, which are nano-sized vesicles with an endosomal origin. Not so long ago, the physiological goal of exosome generation was largely unknown and required more investigation; at first, it was hypothesized that exosomes are able to remove excess, reject and unnecessary constituents from cells to preserve cellular homeostasis. However, thanks to recent studies, the central role of exosomes in regulating cellular communication has emerged. Exosomes act as vectors in cell–cell signaling by their cargo, proteins, lipids, and nucleic acids, and influence physiological and pathological processes. The findings on exosomes are widespread in a large spectrum of biomedical applications from diagnosis and prognosis to therapies. In this review, we describe exosome biogenesis and the current methods for their isolation and characterization, emphasizing the role of their cargo in female reproductive processes, from gametogenesis to implantation, and the potential involvement in human female disorders.
Beyond Nyquist: A Comparative Analysis of 3D Deep Learning Models Enhancing MRI Resolution
Authors: Chatterjee Soumick , Sciarra Alessandro , Dünnwald Max , Ashoka Anitha Bhat Talagini , Vasudeva Mayura Gurjar Cheepinahalli , Saravanan Shudarsan , Sambandham Venkatesh Thirugnana , Tummala Pavan , Oeltze-Jafra Steffen , Speck Oliver , Nürnberger Andreas
Published: August 2024

High-spatial resolution MRI produces abundant structural information, enabling highly accurate clinical diagnosis and image-guided therapeutics. However, the acquisition of high-spatial resolution MRI data typically can come at the expense of less spatial coverage, lower signal-to-noise ratio (SNR), and longer scan time due to physical, physiological and hardware limitations. In order to overcome these limitations, super-resolution MRI deep-learning-based techniques can be utilised. In this work, different state-of-the-art 3D convolution neural network models for super resolution (RRDB, SPSR, UNet, UNet-MSS and ShuffleUNet) were compared for the super-resolution task with the goal of finding the best model in terms of performance and robustness. The public IXI dataset (only structural images) was used. Data were artificially downsampled to obtain lower-resolution spatial MRIs (downsampling factor varying from 8 to 64). When assessing performance using the SSIM metric in the test set, all models performed well. In particular, regardless of the downsampling factor, the UNet consistently obtained the top results. On the other hand, the SPSR model consistently performed worse. In conclusion, UNet and UNet-MSS achieved overall top performances while RRDB performed relatively poorly compared to the other models.
Air-Lift Pumping System for Hybrid Mining of Rare-Earth Elements-Rich Mud and Polymetallic Nodules around Minamitorishima Island
Authors: Shimizu Yoshiyuki , Sugihara Masatoshi , Fujinaga Koichiro , Nakamura Kentaro , Kato Yasuhiro
Published: August 2024

REE-rich mud under the seabed at a 5500–5700 m water depth around Minamitorishima island and polymetallic nodules buried in the deep seabed are very promising and attractive to explore and develop. REEs are critical to develop due to the recent paradigm shift to renewable energies based on green technologies. Numerical analysis using a one-dimensional drift–flux model for gas–liquid–solid three-phase flow and gas–liquid two-phase flow was conducted to examine the characteristics of an air-lift pumping system for mining these mineral resources. Empirical equations of REE-rich mud and the physical properties of polymetallic nodules around Minamitorishima island were utilized in the analysis. As a result, the characteristics, i.e., the performance of the system, were clarified in three cases: REE-rich mud, polymetallic nodules, and both. The time transient, i.e., the unsteady characteristics of the system, was also shown, such as the start-up and feeding slurry with REE-rich mud and polymetallic nodules. The findings from the unsteady characteristics will be useful in considering the operation of a real project or a commercial system in the future.
Opportunistic Interference Alignment in Cognitive Radio Networks with Space–Time Coding
Authors: Abdulkadir Yusuf , Simpson Oluyomi , Sun Yichuang
Published: August 2024

For a multiuser multiple-input–multiple-output (MIMO) overlay cognitive radio (CR) network, an opportunistic interference alignment (IA) technique has been proposed that allows spectrum sharing between primary users (PUs) and secondary users (SUs) while ensuring zero interference to the PU. The CR system consists of one PU and K SUs where the PU uses space-time water-filling (ST-WF) algorithm to optimize its transmission and in the process, frees up unused eigenmodes that can be exploited by the SU. The SUs make use of an optimal power allocation algorithm to align their transmitted signals in such a way their interference impairs only the PUs unused eigenmodes. Since the SUs optimal power allocation algorithm turns out to be an optimal beamformer with multiple eigen-beams, this work initially proposes combining the diversity gain property of space-time block codes, the zero-forcing function of IA and beamforming to optimize the SUs transmission rates. This proposed solution requires availability of channel state information (CSI), and to eliminate the need for CSI, this work then combines Differential Space-Time Block Coding (DSTBC) scheme with optimal IA precoders (consisting of beamforming and zero-forcing) to maximize the SUs data rates. Simulation results confirm the accuracy of the proposed solution.
Emerging Perspectives on Teaching Urban Form: A Blended Learning Approach
Authors: Charalambous Nadia , Oliveira Vitor
Published: August 2024

Over the past few decades, several analytical approaches have been developed to understand urban form and to address the complexity of human settlements as well as various socio-economic and environmental challenges. Each approach is characterized by specific disciplinary and geographical trends, often emerging from distinct schools of thought within urban morphology. Typically, these approaches are associated with specific research centers or individual researchers and have frequently been applied in isolation, with some exceptions. The teaching of urban morphology in higher education institutions across Europe faces the challenge of training future graduates to effectively address contemporary urban issues from often isolated perspectives rooted in the aforementioned schools of thought, either reflecting specific national educational trends or adopting a globalized approach that overlooks local specificities. Furthermore, the relationship between professional practice in urban and planning fields and higher education institutions is a notable concern. While the importance of broad knowledge and multidisciplinary skills for urban professionals is recognized, the connection between academia, research and practice is minimal. The increasing demand for evidence-based approaches in urban design highlights the need for solutions grounded in sound knowledge. To address the relationship between academic research and its integration into professional practice, innovation in teaching practices is crucial, aligning academia with the evolving needs of planning, architecture, and urban design professions. This involves focusing on developing learners’ fundamental and transversal skills and providing tools, methods, and research findings applicable in professional settings. This paper is based on two research projects that sought to bridge the gaps between different morphological approaches in teaching and between academic research and practical application. The projects, Emerging Perspectives on Urban Morphology (EPUM) and the Knowledge Alliance for Evidence-Based Urban Practices (KAEBUP), brought together partners from various South and Central European countries to address these gaps. EPUM focused on integrating different morphological approaches within the context of teaching, while KAEBUP aimed to connect theoretical knowledge with practical actions concerning the built environment. The situative pedagogical perspective, rooted in communities of practice and supported by a blended learning approach, is central to this endeavor. This perspective provides a collaborative framework for educators, students, and professionals in urban morphology to co-create knowledge through integrated learning, teaching, and research activities.
Ecosystem Service and Biodiversity Patterns Observed across Co-Developed Land Use Scenarios in the Piedmont: Lessons Learned for Scale and Framing
Authors: Quinn John E. , Fergus Craig , Hyland Emilia , Vickery Caroline , Lacher Iara L. , Akre Thomas S.
Published: August 2024

Biodiversity and ecosystem service models are frequently used to consider current conditions or recent changes in the availability of a service. The application of scenarios for biodiversity and ecosystem service assessment remains underdeveloped, particularly co-designed and fine-granular scenarios across different decision-making boundaries. Consequently, the data created by these modeling efforts may not be as valuable to conservation partners and policy makers. In this project, we used land use and land cover change scenarios co-developed with local and regional decision-makers in northwestern Virginia USA as key inputs for 18 different biodiversity and ecosystem service models. Specifically, we used the InVEST suite of models to predict the change in biodiversity and ecosystem indicators and evaluated differences in that change between scenarios and decision-making boundaries. We found that the scenarios produced distinct results for the majority of biodiversity and ecosystem services, especially as a function of population growth. However, we also found that some services varied more as a function of subregions reflecting the existing diversity of ecosystems and governance structures in the area. The co-designed scenarios and summary of the data across units resulted in the production of varied results that can be used to support land use planning by implementing partners.
Maintaining the Indigenous Udmurt Language beyond the Community: An Autoethnographic Analysis
Authors: Edygarova Svetlana
Published: August 2024

In this article, I emphasize the importance of maintaining and transmitting indigenous languages to the next generations, and I explore the motivations and difficulties of indigenous language speakers to do so when living far away from their native language community. The article is an autoethnographic analysis that amplifies the insider’s perspective and reflects on my own thoughts, perceptions, and emotional reactions regarding my language use practices. Specifically, I analyze the use of the Udmurt language with my children and the process of writing a blog in Udmurt. As a researcher of the Udmurt language, I use my previous sociolinguistic studies in the analysis and place it within the broader context of indigenous peoples from Russia. Indigenous languages often involve the use of multiple languages simultaneously, including language mixing, which is entirely natural. In societies with a monolingual language ideology, such practices are seen as signs of linguistic incompetence, leading to feelings of shame or inferiority among indigenous speakers. This negatively impacts the preservation of indigenous languages. Raising sociolinguistic and emotional awareness about how indigenous languages function and sharing personal experiences, including negative ones, can help overcome these challenges.
Impact of Plasminogen Activator Inhibitor-1 Serum Levels and the -675 4G/5G Variant in the SERPINE1 Gene on Systemic Sclerosis in a Mexican Population
Authors: Lomelí-Nieto José Alvaro , Muñoz-Valle José Francisco , Navarro-Zarza José Eduardo , Baños-Hernández Christian Johana , Gutierrez-Brito Jesús Alberto , Renteria-Cabrera Valeria , Horta-Chávez Eduardo Arturo , Morales-Núñez José Javier , García-Arellano Samuel , Parra-Rojas Isela , Hernández-Bello Jorge
Published: August 2024

Systemic sclerosis (SSc) is characterized by a complex interplay of vascular damage, inflammation, and fibrosis, affecting the skin and internal organs. Plasminogen activator inhibitor-1 (PAI-1), a protein encoded by the SERPINE1 gene, is a potential biomarker of SSc because it is primarily involved in fibrinolysis and is associated with the severity of some autoimmune diseases. This study aimed to determine the association between SERPINE1 variant -675 4G/5G and soluble PAI-1 (sPAI-1) levels with the clinical characteristics and risk of SSc in a Mexican population. This cross-sectional study included 56 SSc patients and 114 control subjects (CSs). The variant was genotyped via the PCR–RFLP method and the levels of sPAI-1 were determined using enzyme-linked immunosorbent assays (ELISAs). The -675 4G/5G variant was not associated with SSc risk or sPAI-I levels. However, higher sPAI-1 levels were observed in SSc patients than in CSs (p = 0.045); these levels were significantly correlated with age, platelets, glucose, and serum levels of transforming growth factor (TGF)-β1, 2, and 3. The SERPINE1 -675 4G/5G variant did not show any association with SSc risk or sPAI-I levels. However, our study shows a possible alteration of sPAI-1 in this disease, which could be associated with the fibrotic and thrombotic processes in SSc.
Green Preparation of S, N Co-Doped Low-Dimensional C Nanoribbon/C Dot Composites and Their Optoelectronic Response Properties in the Visible and NIR Regions
Authors: Ma Xingfa , Zhang Xintao , Gao Mingjun , Wang You , Li Guang
Published: August 2024

The green production of nanocomposites holds great potential for the development of new materials. Graphene is an important class of carbon-based materials. Despite its high carrier mobility, it has low light absorption and is a zero-bandgap material. In order to tune the bandgap and improve the light absorption, S, N co-doped low-dimensional C/C nanocomposites with polymer and graphene oxide nanoribbons (the graphene oxide nanoribbons were prepared by open zipping of carbon nanotubes in a previous study) were synthesized by one-pot carbonization through dimensional-interface and phase-interface tailoring of nanocomposites in this paper. The resulting C/C nanocomposites were coated on untreated A4 printing paper and the optoelectronic properties were investigated. The results showed that the S, N co-doped C/C nanoribbon/carbon dot hybrid exhibited enhanced photocurrent signals of the typical 650, 808, 980, and 1064 nm light sources and rapid interfacial charge transfer compared to the N-doped counterpart. These results can be attributed to the introduction of lone electron pairs of S, N elements, resulting in more transition energy and the defect passivation of carbon materials. In addition, the nanocomposite also exhibited some electrical switching response to the applied strain. The photophysical and doping mechanisms are discussed. This study provides a facile and green chemical approach to prepare hybrid materials with external stimuli response and multifunctionality. It provides some valuable information for the design of C/C functional nanocomposites through dimensional-interface and phase-interface tailoring and the interdisciplinary applications.
A Review on Concrete Superplasticizers and Their Potential Applications for Enhancing the Performance of Thermally Activated Recycled Cement
Authors: Huang Rong , Xu Lei , Xu Zihang , Zhang Qihang , Wang Junjie
Published: August 2024

With the rapid development of the construction industry worldwide, a large amount of waste concrete is generated each year, which has caused serious environmental problems. As a green and sustainable building material, thermally activated recycled cement (RC) has received widespread attention. However, the unique properties of RC, such as the high water demand and short setting time, necessitate the use of specialized superplasticizers that are different from those used in ordinary Portland cement. As an important component for the application of RC, superplasticizer has an important impact on the performance modification of RC. This article summarizes the recent research progress of potential superplasticizers for RC, with a view to providing a reference for the research and application of superplasticizers for RC. Based on the differences between ordinary Portland cement and RC, the paper discusses potential superplasticizers that may be suitable for RC, and points out that future development of potential modified superplasticizers can include altering the molecular structure to improve adsorption onto the surfaces of RC or to enhance the durability of concrete with RC.
Towards Sustainable Orthodontics: Environmental Implications and Strategies for Clear Aligner Therapy
Authors: Macrì Monica , D’Albis Vincenzo , Marciani Raffaele , Nardella Matteo , Festa Felice
Published: August 2024

The increasing concern over environmental sustainability has prompted various industries to reassess their practices and explore greener alternatives. Dentistry, as a significant contributor to waste generation, is actively seeking methods to minimize its environmental footprint. This paper examines the environmental implications of clear aligner therapy (CAT) in orthodontics and explores strategies to prioritize sustainability in aligner manufacturing and usage. CAT has gained popularity as a viable alternative to traditional fixed appliances due to advancements in biomaterials and computer-aided design (CAD) and manufacturing (CAM) technologies. The global market for clear aligners is expanding rapidly, with significant growth projected in the coming years. To address these challenges, this paper proposes adopting the principles of reduce, reuse, recycle, and rethink (4Rs) in orthodontic practices. Strategies such as minimizing resource consumption, incorporating recycled materials, and promoting proper aligner disposal and recycling can significantly reduce environmental harm. This paper explores emerging technologies and materials to mitigate the environmental impacts of CAT. Additionally, initiatives promoting aligner recycling and repurposing offer promising avenues for reducing plastic waste and fostering a circular economy. In conclusion, while CAT offers numerous benefits in orthodontic treatment, its environmental impact cannot be overlooked. By implementing sustainable practices and embracing innovative solutions, the orthodontic community can contribute to a more environmentally conscious future while continuing to provide quality care to patients.
A Comprehensive Review on Finite Element Analysis of Laser Shock Peening
Authors: Wakchaure Mayur B. , Misra Manoranjan , Menezes Pradeep L.
Published: August 2024

Laser shock peening (LSP) is a formidable cold working surface treatment that provides high-energy precision to enhance the mechanical properties of materials. This paper delves into the intricacies of the LSP process, offering insights into its methodology and the simulation thereof through the finite element method. This review critically examines various points, such as laser energy, overlapping of shots, effect of LSP on residual stress, effect of LSP on grain refinement, and algorithms for simulation extrapolated from finite element analyses conducted by researchers, shedding light on the nuanced considerations integral to this technique. As the significance of LSP continues to grow, the collective findings underscore its potential as a transformative technology for fortifying materials against mechanical stress and improving their overall performance and longevity. The discourse encapsulates the evolving landscape of the LSP, emphasizing the pivotal role played by finite element analysis in advancing our understanding and application of this innovative surface treatment.
Materials Properties Prediction (MAPP): Empowering the Prediction of Material Properties Solely Based on Chemical Formulas
Authors: Xue Si-Da , Hong Qi-Jun
Published: August 2024

Predicting material properties has always been a challenging task in materials science. With the emergence of machine learning methodologies, new avenues have opened up. In this study, we build upon our recently developed graph neural network (GNN) approach to construct models that predict four distinct material properties. Our graph model represents materials as element graphs, with chemical formulas serving as the only input. This approach ensures permutation invariance, offering a robust solution to prior limitations. By employing bootstrap methods to train this individual GNN, we further enhance the reliability and accuracy of our predictions. With multi-task learning, we harness the power of extensive datasets to boost the performance of smaller ones. We introduce the inaugural version of the Materials Properties Prediction (MAPP) framework, empowering the prediction of material properties solely based on chemical formulas.
Discharge Properties and Electrochemical Behaviors of Mg-Zn-xSr Magnesium Anodes for Mg–Air Batteries
Authors: Liu Hongxuan , Zhang Tingan , Xu Jingzhong
Published: August 2024

In this work, the electrochemical and discharge properties of Mg-Zn-xSr (x = 0, 0.2, 0.5, 1, 2, and 4 wt.%) alloys used as anodes for Mg–air batteries were systematically studied via microstructure characterization, electrochemical techniques, and Mg–air battery test methods. The addition of Sr refines the grain size, changes the composition and morphology of the passivation film and discharge products, and enhances the electrochemical properties of the alloy. Excessive Sr addition breaks the grain boundaries and precipitates a large number of Sr-rich phases, resulting in microgalvanic corrosion and the ‘chunk effect’. The anode efficiency of Mg-Zn-1Sr is the highest at a current density of 10 mA cm−2, reaching 61.86%, and the energy density is 2019 mW h g−1. Therefore, Sr is a microalloying element that can optimize the electrochemical performance of Mg–air battery alloy anodes.
Application of Numerical Modeling and Finite Element Analysis in Fused Filament Fabrication: A Review
Authors: Behseresht Saeed , Park Young Ho , Love Allen , Valdez Pastrana Omar Alejandro
Published: August 2024

Additive manufacturing (AM) is not necessarily a new process but an advanced method for manufacturing complex three-dimensional (3D) parts. Among the several advantages of AM are the affordable cost, capability of building objects with complex structures for small-batch production, and raw material versatility. There are several sub-categories of AM, among which is fused filament fabrication (FFF), also commonly known as fused deposition modeling (FDM). FFF has been one of the most widely used additive manufacturing techniques due to its cost-efficiency, simplicity, and widespread availability. The FFF process is mainly used to create 3D parts made of thermoplastic polymers, and complex physical phenomena such as melt flow, heat transfer, solidification, crystallization, etc. are involved in the FFF process. Different techniques have been developed and employed to analyze these phenomena, including experimental, analytical, numerical, and finite element analysis (FEA). This study specifically aims to provide a comprehensive review of the developed numerical models and simulation tools used to analyze melt flow behavior, heat transfer, crystallization and solidification kinetics, structural analysis, and the material characterization of polymeric components in the FFF process. The strengths and weaknesses of these numerical models are discussed, simplifications and assumptions are highlighted, and an outlook on future work in the numerical modeling and FE simulation of FFF is provided.
Fabrication and Characterization of Polycaprolactone–Baghdadite Nanofibers by Electrospinning Method for Tissue Engineering Applications
Authors: Forogh Mir Reza , Emadi Rahmatollah , Ahmadian Mehdi , Saboori Abdollah
Published: August 2024

This work investigates the essential constituents, production methods, and properties of polycaprolactone (PCL) and Baghdadite fibrous scaffolds. In this research, electrospinning was used to produce fiber ropes. In this study, the Baghdadite powder was synthesized using the sol–gel method and incorporated into PCL’s polymeric matrix in formic acid and acetic acid solvents. The present work examined PCL–Baghdadite fibrous scaffolds at 1%, 3%, and 5 wt% for morphology, fiber diameter size, hydrophilicity, porosity, mechanical properties, degradability, and bioactivity. The introduction of Baghdadite nanopowder into pure PCL scaffolds reduced fiber diameter. The wetting angle decreased when Baghdadite nanopowder was added to fibrous scaffolds. Pure PCL reduced the wetting angle from 93.20° to 70.53°. Fibrous PCL scaffolds with Baghdadite nanopowder have better mechanical characteristics. The tensile strength of pure PCL fibers was determined at 2.08 ± 0.2 MPa, which was enhanced by up to 3 wt% by adding Baghdadite nanopowder. Fiber elasticity increased with tensile strength. Baghdadite at a 5% weight percentage reduced failure strain percentage. Fibers with more Baghdadite nanopowder biodegrade faster. Adding Baghdadite ceramic nanoparticles resulted in increased bioactivity and caused scaffolds to generate hydroxyapatite. The results show that Baghdadite PCL-3 wt% fibers have promising shape, diameter, and mechanical qualities. After 24 h, L-929 fibroblast cell viability was greater in the scaffold with 3% Baghdadite weight compared to the pure PCL. PCL-3 wt% Baghdadite fibers generated hydroxyapatite on the surface and degraded well. Based on the above findings, PCL fibers having 3 wt% of Baghdadite are the best sample for tissue engineering applications that heal flaws.
Performance Analysis of New One-Piece Iron Roughneck and Its Spinning Mechanism
Authors: Sha Yongbai , Han Donghe , Chen Donghu , Liu Congzhi
Published: August 2024

The iron roughneck is an automated piece of equipment utilized for the connection and removal of drilling tools. This paper presents the design of an integrated iron roughneck, providing a detailed introduction to its clamp body structure, along with an analysis of its structural characteristics and performance requirements. The study delves into the integration mode and working characteristics of the clamping mechanism and spin buckle mechanism for the integrated upper clamp body structure of the iron roughneck. Additionally, this paper conducts an in-depth theoretical study on the spin buckle mechanism. Firstly, it analyzes the actual working condition of the spin buckle roller from two perspectives, namely contact theory and rolling friction theory, determining the structural form of the spin buckle roller. Secondly, it investigates the relative displacement between the spin buckle mechanism and the drilling tool, proposing a design method for the floating device mounted on the spin buckle roller and establishing the kinematic equation of the spin buckle roller under the influence of the floating device. Furthermore, the kinematic equations of the spin buckle roller under the influence of the floating device are established. Finally, a dynamics simulation experiment is performed to simulate the working process of the spin buckle mechanism under actual working conditions, analyzing the dynamics and kinematics of the spin buckle mechanism and obtaining the relevant parameter curves of the spin buckle mechanism and drilling tools. Through data comparison and analysis, the correctness of the theoretical analysis results and the rationality of the performance and structure of the spin buckle mechanism are verified.
Flow Field Noise Analysis and Noise Reduction Research of Twin-Screw Air Compressor Based on Multi-Field Coupling Technology
Authors: He Yayin , He Xuyang , Chen Lijun , Wang Junli , Zhao Yongqiang , Ren Zhigui
Published: August 2024

To address the flow field noise problem in twin-screw air compressors, multi-physical-field coupling technology is employed to perform flow field noise calculations for the compressor. Based on the structural characteristics and noise generation principles of the twin-screw compressor, a noise reduction design method is proposed that employs a Helmholtz resonator and a three-chamber perforated muffler at the exhaust end. The muffler’s structural optimization is performed using a genetic algorithm, and the effectiveness of the noise reduction method is validated through calculations. The results indicate that the Helmholtz resonator effectively mitigates airflow pulsation at the exhaust port, stabilizing the flow and reducing low-frequency noise at the exhaust end. Additionally, the designed three-chamber perforated muffler achieves noise reduction across a broad frequency range. With this noise reduction method, the exhaust port noise of the twin-screw compressor is reduced from 100–114 dB to 37–68 dB. These findings provide valuable insights for vibration and noise reduction in twin-screw air compressors.
Majorization Problem for q-General Family of Functions with Bounded Radius Rotations
Authors: Jabeen Kanwal , Saliu Afis , Gong Jianhua , Hussain Saqib
Published: August 2024

In this paper, we first prove the q-version of Schwarz Pick’s lemma. This result improved the one presented earlier in the literature without proof. Using this novel result, we study the majorization problem for the q-general class of functions with bounded radius rotations, which we introduce here. In addition, the coefficient bound for majorized functions related to this class is derived. Relaxing the majorized condition on this general family, we obtain the estimate of coefficient bounds associated with the class. Consequently, we present new results as corollaries and point out relevant connections between the main results obtained from the ones in the literature.
Integrating Sensor Embeddings with Variant Transformer Graph Networks for Enhanced Anomaly Detection in Multi-Source Data
Authors: Meng Fanjie , Ma Liwei , Chen Yixin , He Wangpeng , Wang Zhaoqiang , Wang Yu
Published: August 2024

With the rapid development of sensor technology, the anomaly detection of multi-source time series data becomes more and more important. Traditional anomaly detection methods deal with the temporal and spatial information in the data independently, and fail to make full use of the potential of spatio-temporal information. To address this issue, this paper proposes a novel integration method that combines sensor embeddings and temporal representation networks, effectively exploiting spatio-temporal dynamics. In addition, the graph neural network is introduced to skillfully simulate the complexity of multi-source heterogeneous data. By applying a dual loss function—consisting of a reconstruction loss and a prediction loss—we further improve the accuracy of anomaly detection. This strategy not only promotes the ability to learn normal behavior patterns from historical data, but also significantly improves the predictive ability of the model, making anomaly detection more accurate. Experimental results on four multi-source sensor datasets show that our proposed method performs better than the existing models. In addition, our approach enhances the ability to interpret anomaly detection by analyzing the sensors associated with the detected anomalies.
The Wiener Process with a Random Non-Monotone Hazard Rate-Based Drift
Authors: Rodríguez-Picón Luis Alberto , Méndez-González Luis Carlos , Pérez-Domínguez Luis Asunción , Tovanche-Picón Héctor Eduardo
Published: August 2024

Several variations of stochastic processes have been studied in the literature to obtain reliability estimations of products and systems from degradation data. As the degradation trajectories may have different degradation rates, it is necessary to consider alternatives to characterize their individual behavior. Some stochastic processes have a constant drift parameter, which defines the mean rate of the degradation process. However, for some cases, the mean rate must not be considered as constant, which means that the rate varies in the different stages of the degradation process. This poses an opportunity to study alternative strategies that allow to model this variation in the drift. For this, we consider the Hjorth rate, which is a failure rate that can define different shapes depending on the values of its parameters. In this paper, the integration of this hazard rate with the Wiener process is studied to individually identify the degradation rate of multiple degradation trajectories. Random effects are considered in the model to estimate a parameter of the Hjorth rate for every degradation trajectory, which allows us to identify the type of rate. The reliability functions of the proposed model is obtained through numerical integration as the function results in a complex form. The proposed model is illustrated in two case studies based on a crack propagation and infrared LED datasets. It is found that the proposed approach has better performance for the reliability estimation of products based on information criteria.
The Impact of Digital Economy on TFP of Industries: Empirical Analysis Based on the Extension of Schumpeterian Model to Complex Economic Systems
Authors: Liu Jiaqi , Cheng Yiyang , Fu Yamei , Xue Fei
Published: August 2024

The digital economy (DE) is a new driver for enhancing total factor productivity (TFP). Using panel data from 30 provinces in China between 2011 and 2022, this study measures DE and TFP using the entropy-weighted TOPSIS method and the Global Malmquist–Luenberger method and further examines the impact of DE on the TFP of industries. The main findings are as follows: (1) DE can significantly improve TFP, though the extent of improvement varies. DE has the greatest impact on the TFP of the service industry, followed by the manufacturing industry, with the weakest effect on the agricultural industry. (2) The enhancement effect of DE on agriculture and the service industry is more pronounced in the central and western regions, while the improvement effect on manufacturing is more evident in the eastern region. (3) DE has facilitated the improvement of TFP in manufacturing industries such as textiles and special equipment manufacturing, as well as in service industries like wholesale and retail. However, it has not had a significant impact on the TFP of industries such as pharmaceutical manufacturing and real estate. This study has significant theoretical value and policy implications for China and other developing countries in exploring DE and achieving high-quality industrial development.
Investigation of the Surface Characteristics of GCr15 in Electrochemical Machining
Authors: Liu Xuesong , Su Guokang , Fan Qingming , Zhang Yongjun , Chen Hua , Zhang Chuanyun
Published: August 2024

Bearing steel (GCr15) is widely used in key parts of mechanical transmission for its excellent mechanical properties. Electrochemical machining (ECM) is a potential method for machining GCr15, as the machining process is the electrochemical dissolution of GCr15 regardless of its high hardness (>50 HRC). In ECM, NaNO3 solution is a popular electrolyte, as it has the ability to help in the nonlinear dissolution of many metallic alloy materials, making it useful for precision machining. However, due to high carbon content of GCr15, the electrochemical dissolution of GCr15 is unique, and there is always a black layer with high roughness on the machined surface, reducing the surface quality. In order to improve the electrochemical machining of GCr15 with a high surface quality, the surface characteristics of GCr15 in ECM were investigated. The anodic polarisation curve in the NaNO3 electrolyte was measured and electrochemical dissolution experiments were conducted with different current densities. SEM, XRD, and XPS were employed to analyse the surface morphology and composition formed on the machined surface at different current densities. The initial results showed that there were two parts (black part and bright part) formed on the machined surface when a short circuit occurred, and the test results suggested that the black part contained a mass of Fe3O4 while the bright part was composed of mainly Fe and Fe3C. Further investigation uncovered that a black flocculent layer (Fe3O4) always formed in a low current density (32 A/cm2) with high roughness. With the current density increased, the amount of black flocculent layer was reduced, and Fe3C particles appeared on the machined surface. When the current density reached 81 A/cm2, the entire flocculent oxide layer was removed, only some spherical Fe3C particles were inserted on the machined surface, and the roughness was reduced from Ra7.743 μm to Ra1.783 μm. In addition, due to exposed Fe3C particles on the machined surface, the corrosion resistance of the machined surface was significantly improved. Finally, circular arc grooves of high quality were well manufactured with current density of 81 A/cm2 in NaNO3 electrolyte.
Offsetting Dense Particle Sedimentation in Microfluidic Systems
Authors: Anyaduba Tochukwu Dubem , Rodriguez-Manzano Jesus
Published: August 2024

Sedimentation is an undesirable phenomenon that complicates the design of microsystems that exploit dense microparticles as delivery tools, especially in biotechnological applications. It often informs the integration of continuous mixing modules, consequently impacting the system footprint, cost, and complexity. The impact of sedimentation is significantly worse in systems designed with the intent of particle metering or binary encapsulation in droplets. Circumventing this problem involves the unsatisfactory adoption of gel microparticles as an alternative. This paper presents two solutions—a hydrodynamic solution that changes the particle sedimentation trajectory relative to a flow-rate dependent resultant force, and induced hindered settling (i-HS), which exploits Richardson–Zaki (RZ) corrections of Stokes’ law. The hydrodynamic solution was validated using a multi-well fluidic multiplexing and particle metering manifold. Computational image analysis of multiplex metering efficiency using this method showed an average reduction in well-to-well variation in particle concentration from 45% (Q = 1 mL/min, n = 32 total wells) to 17% (Q = 10 mL/min, n = 48 total wells). By exploiting a physical property (cloud point) of surfactants in the bead suspension in vials, the i-HS achieved a 58% reduction in the sedimentation rate. This effect results from the surfactant phase change, which increases the turbidity (transient increase in particle concentration), thereby exploiting the RZ theories. Both methods can be used independently or synergistically to eliminate bead settling in microsystems or to minimize particle sedimentation
Development of Highly Sensitive and Thermostable Microelectromechanical System Pressure Sensor Based on Array-Type Aluminum–Silicon Hybrid Structures
Authors: Li Min , Xiao Yang , Zhang Jiahong , Liu Qingquan , Jiang Xianglong , Hua Wenhao
Published: August 2024

In order to meet the better performance requirements of pressure detection, a microelectromechanical system (MEMS) piezoresistive pressure sensor utilizing an array-type aluminum–silicon hybrid structure with high sensitivity and low temperature drift is designed, fabricated, and characterized. Each element of the 3 × 3 sensor array has one stress-sensitive aluminum–silicon hybrid structure on the strain membrane for measuring pressure and another temperature-dependent structure outside the strain membrane for measuring temperature and temperature drift compensation. Finite-element numerical simulation has been adopted to verify that the array-type pressure sensor has an enhanced piezoresistive effect and high sensitivity, and then this sensor is fabricated based on the standard MEMS process. In order to further reduce the temperature drift, a thermodynamic control system whose heating feedback temperature is measured by the temperature-dependent structure is adopted to keep the working temperature of the sensor constant by using the PID algorithm. The experiment test results show that the average sensitivity of the proposed sensor after temperature compensation reaches 0.25 mV/ (V kPa) in the range of 0–370 kPa, the average nonlinear error is about 1.7%, and the thermal sensitivity drift coefficient (TCS) is reduced to 0.0152%FS/°C when the ambient temperature ranges from −20 °C to 50 °C. The research results may provide a useful reference for the development of a high-performance MEMS array-type pressure sensor.
New Iflavirus Species Characterized from Mosquitoes Captured in the Sao Paulo Zoological Facilities
Authors: Guimarães Lilian de Oliveira , Bahia Santana Lobato , Ribeiro Geovani de Oliveira , Ramos Endrya do Socorro Foro , Villanova Fabiola , dos Santos Morais Vanessa , Telles-de-Deus Juliana , Helfstein Vanessa Christe , Santos Jesus Maia dos , Pandey Ramendra Pati , Deng Xutao , Delwart Eric , Camargo-Neves Vera Lucia Fonseca de , da Costa Antonio Charlys , Kirchgatter Karin , Leal Élcio
Published: August 2024

Metagenomic studies of mosquito viromes demonstrated a more diverse composition than just an exclusive composition of pathogenic arboviruses transmitted to humans. In our study, the virome of 866 female mosquitoes collected throughout 2020 at the São Paulo Zoo, located in the city of São Paulo/SP—Brazil, was obtained. Specifically, in this paper, we describe a new virus found by viral RNA extraction and next-generation MiSeq sequencing of a group of 23 specimens of Anopheles (Nys.) strodei. The complete genome with a length of 9709 nucleotides was characterized by a positive orientation and a single strand, with a single large ORF, which encodes a polyprotein of 2987 amino acids. The phylogenetic analysis showed an association with the viral family Iflaviridae and the Riboviria realm. We carried out comparisons with translated sequences of the capsid regions of other iflavirus, and the identities in relation to our sequence were below the minimum limit of 90%, indicating that possibly it is a new species of iflavirus. Our findings contribute to expanding knowledge of virome composition among mosquito species in Brazil and globally. Moreover, we provide a viral genome reference specific to this geographic region and Culicidae family of mosquitoes. This resource facilitates future in silico recognition and assembly of viral genomes within metagenomic datasets.
Complex Formation of Ag+ and Li+ with Host Molecules Modeled on Intercalation of Graphite
Authors: Uetake Yuriko , Takemura Hiroyuki
Published: August 2024

Pi-stacked and box-shaped host molecules with xanthene as the basis and pyrene as the π-plane were synthesized to verify cation–π interactions between graphene and metal cations. Since crystal structure analysis was not available, DFT calculations were performed to determine the optimized structure, and the π-planes were found to have a slipped parallel structure, with average distances of 456.2–581.0 pm for the stacked compound and 463.4–471.4 pm for the box-shaped compound. Li+ and Ag+ were chosen as acceptors for complexation with metal ions, and their interactions with the π-plane were clarified by NMR titration. Clearly, the interaction with metal ions increased when pyrene π-planes were stacked rather than the pyrene itself. In the stacked compound, the association constants of Ag+ and Li+ were similar; however, in the box-shaped host molecule, only Ag+ had moderate coordination ability, but the interaction with Li+ was very weak, comparable to the interaction with pyrene. As a result, intercalation is more likely to occur in stacked host compound 1, which has some degree of freedom in the pyrene rings, than in the box-shaped compound.
Lupeol-3-carbamate Derivatives: Synthesis and Biological Evaluation as Potential Antitumor Agents
Authors: Tian Shuang , Zhao Yinxu , Deng Siqi , Hou Liman , Song Juan , Wang Ming , Bu Ming
Published: August 2024

In the following study, a series of new lupeol-3-carbamate derivatives were synthesized, and the structures of all the newly derived compounds were characterized. The new compounds were screened to determine their anti-proliferative activity against human lung cancer cell line A549, human liver cancer cell line HepG2, and human breast cancer cell line MCF-7. Most of the compounds were found to show better anti-proliferative activity in vitro than lupeol. Among them, obvious anti-proliferation activity (IC50 = 5.39~9.43 μM) was exhibited by compound 3i against all three tumor cell lines. In addition, a salt reaction was performed on compound 3k (IC50 = 13.98 μM) and it was observed that the anti-proliferative activity and water solubility of compound 3k·CH3I (IC50 = 3.13 μM), were significantly enhanced subsequent to the salt formation process. The preliminary mechanistic studies demonstrated that apoptosis in HepG2 cells was induced by compound 3k·CH3I through the inhibition of the PI3K/AKT/mTOR pathway. In conclusion, a series of new lupeol-3-carbamate derivatives were synthesized via the structural modification of the C-3 site of lupeol, thus laying a theoretical foundation for the design of this new anticancer drug.