bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing protein aggregation prediction: a unified analysis leveraging graph convolutional networks and active learning
Authors: Sun Jiwon , Song JunHo , Kim Juo , Kang Seungpyo , Park Eunyoung , Seo Seung-woo , Min Kyoungmin
Published: October 2024

A graph convolution neural network (GCN) model was developed to predict the aggregation propensity of human protein. The model was applied to protein structures derived from the AlphaFold 2.0 dataset, demonstrating its ability to accurately assess protein aggregation of human protein structure.
Ultra-high sensitivity and ultra-stable flexible wearable sensors based on hyperelastic semiconductor fibers
Authors: Li Meiying , Wang Yuting , Sun Shouheng , Wan Chubin , Wang Yanli , Li Ruikai , Tang Anchun , Ju Xin
Published: October 2024

Assembly and sensing mechanism diagram of double-layer PVP/SnO2 nanofiber sensor.
Influence of crossover on capacity fade of symmetric redox flow cells
Authors: George Thomas Y. , Fell Eric M. , Lee Kyumin , Emanuel Michael S. , Aziz Michael J.
Published: October 2024

Volumetrically unbalanced compositionally symmetric cell cycling with potentiostatic (CV) or galvanostatic-with-potential-hold (CCCV) protocols is a rigorous technique for evaluating the calendar lifetime of reactants for redox flow batteries.
Competing effects of low salt ratio on electrochemical performance and compressive modulus of PEO-LiTFSI/LLZTO composite electrolytes
Authors: Zhang Jiaxin , Perez Valeria , Garcia ThomasJae , Yoon Dan-il , Wagner David , Schneider Yanika , Lee Min Hwan , Lee Sang-Joon John , Oh Dahyun
Published: October 2024

Stable Li cycling of solid-composite electrolytes with a low amount of Li salt.
Terahertz image denoising via multiscale hybrid‐convolution residual network
Authors: Wu Heng , Guo Zijie , He Chunhua , Luo Shaojuan , Song Bofang
Published: October 2024

Terahertz imaging technology has great potential applications in areas, such as remote sensing, navigation, security checks, and so on. However, terahertz images usually have the problems of heavy noises and low resolution. Previous terahertz image denoising methods are mainly based on traditional image processing methods, which have limited denoising effects on the terahertz noise. Existing deep learning‐based image denoising methods are mostly used in natural images and easily cause a large amount of detail loss when denoising terahertz images. Here, a residual‐learning‐based multiscale hybrid‐convolution residual network (MHRNet) is proposed for terahertz image denoising, which can remove noises while preserving detail features in terahertz images. Specifically, a multiscale hybrid‐convolution residual block (MHRB) is designed to extract rich detail features and local prediction residual noise from terahertz images. Specifically, MHRB is a residual structure composed of a multiscale dilated convolution block, a bottleneck layer, and a multiscale convolution block. MHRNet uses the MHRB and global residual learning to achieve terahertz image denoising. Ablation studies are performed to validate the effectiveness of MHRB. A series of experiments are conducted on the public terahertz image datasets. The experimental results demonstrate that MHRNet has an excellent denoising effect on synthetic and real noisy terahertz images. Compared with existing methods, MHRNet achieves comprehensive competitive results.
An effective ensemble electricity theft detection algorithm for smart grid
Authors: Tsai Chun‐Wei , Lu Chi‐Tse , Li Chun‐Hua , Zhang Shuo‐Wen
Published: October 2024

Several machine learning and deep learning algorithms have been presented to detect the criminal behaviours in a smart grid environment in recent studies because of many successful results. However, most learning algorithms for the electricity theft detection have their pros and cons; hence, a critical research issue nowadays has been how to develop an effective detection algorithm that leverages the strengths of different learning algorithms. To demonstrate the performance of such an integrated detection model, the algorithm proposed first builds on deep neural networks, a meta‐learner for determining the weights of detection models for the construction of an ensemble detection algorithm and then uses a promising metaheuristic algorithm named search economics to optimise the hyperparameters of the meta‐learner. Experimental results show that the proposed algorithm is able to find better results and outperforms all the other state‐of‐the‐art detection algorithms for electricity theft detection compared in terms of the accuracy, F1‐score, area under the curve of precision‐recall (AUC‐PR), and area under the curve of receiver operating characteristic (AUC‐ROC). Since the results show that the meta‐learner of the proposed algorithm can improve the accuracy of deep learning algorithms, the authors expect that it will be used in other deep learning‐based applications.
Conceptual design of an amphibious boat as a mitigation support solution
Authors: Prasetyo Naufal Abdurrahman , Cahyagi Danang , Satoto Sapto Wiratno , Yogantara Yogantara , Wahyu Eko , Luthfy Muhammad , Davin Muhammad , Gratia Charitas
Published: October 2024

This study has initiate to create a conceptual design an amphibious vehicle for flood disaster mitigation in Batam, Riau Islands, focusing on simplifying the design process to reduce complexity, costs, and production time while enhancing efficiency. Batam, near Singapore, frequently experiences coastal flooding, impact residential areas and the local economy. Effective rescue vehicles are critical for evacuations, as demonstrated by the 2024 Batam flood. The vehicle, named Amphi-boat integrates land-based and water-based propulsion systems, using lightweight, strong materials, a robust suspension system, and a simplified structure. Composite materials are recommended for their high strength-toweight ratio. The design methodology considers operational requirements, technical criteria, and limitations, informed by existing vehicles. A modular design approach is suggested to facilitate easier assembly, repair, and cost reduction. Technical performance assessments ensure vehicle stability and functionality. The study produces a conceptual model of an amphibious rescue vehicle, showcasing its capabilities on land and on water. It concludes that a simplified design can expedite development and reduce costs, offering a practical solution for flood disaster mitigation and advancing amphibious vehicle technology.
Leveraging machine learning for hydrological drought prediction and mitigation
Authors: Cahyaningsih Eka , Hadiani R.R. Rintis , Ikhsan Cahyono
Published: October 2024

Drought disasters have become a global issue, occurring more frequently due to climate change and increasing water usage patterns. Adaptation and mitigation efforts to reduce disaster vulnerability involve effective drought monitoring, such as drought predictions. This study aims to predict the hydrological drought index (HDI) for the next 5 years (20242028) in the Bendung Notog sub-watershed. The HDI prediction modeling is based on machine learning with an artificial neural network (ANN) algorithm using historical HDI values from the past 20 years (2004-2023). The historical HDI was calculated using the Threshold Level Method with discharge data transformed by the NRECA method. The drought prediction model demonstrates high accuracy with performance assessment values of MAE = 0.015, R = 0.91, R2 = 0.82, NSE = 0.82, and RMSE = 0.022. The HDI prediction results indicate that the Bendung Notog sub-watershed experiences dry conditions annually during the dry season, with the lowest HDI and longest drought duration occurring in 2024. Hydrological drought prediction is essential to minimize the negative impacts due to reduced water discharge, enabling strategic planning for future water needs.
Sediment Transport Modeling in The Katingan I Tidal Irrigation, Central Kalimantan
Authors: Winarto Nigel Geraldi , Sujono Joko , Kironoto Bambang Agus
Published: October 2024

The utilization of swamp land as productive rice fields is to support national food security and the local economy. One of which is carried out through the Katingan I tidal swamp irrigation rehabilitation project. In the Katingan I tidal swamp irrigation area, sedimentation problems occurred in the channels. The Sedimentation reduces the water flow capacity in primary and secondary canals as a water supply for agricultural fields which can have an impact on decreasing paddy production. This study was conducted to model sediment using HEC-RAS 6.4.1 software and to identify the areas affected by sedimentation in the Katingan I tidal swamp irrigation canals. Data collection methods included direct observation of tidal heights over a one-month observation period on the Katingan River. The study results show that the lower right primary canal 13 (PBKn 13) has the highest sediment volume and the invert channel increased by 1.81 % per month. The recommendations to address the issue include rehabilitation and normalization of the canal to control the impact of sedimentations.
Effect of Bubble Cap Distributor Plate Configuration on Pressure Drop in a Bubbling Fluidized Bed Reactor
Authors: Sonjaya Abeth Novria , Auzani Ahmad Syihan , Zuldian Prima , Suryosatyo Adi
Published: October 2024

In designing a fluidized bed reactor, the gas distribution plate plays a pivotal role. It ensures proper functioning of the gas-solid fluidized bed. This study investigated two types of distributor plates: perforated and bubble caps, with sintered and triangular configurations. The aim was to compare the pressure drop when air flowed through these distributors. The bed material comprised oil palm frond particles (420 µm in size, 200 gr, bulk density of 100.201 kg/m3) and silica sand, with different column diameters (2 inch, 4 inch, and 6 inch). Observations were made on pressure drops under both cold and hot flow model conditions. The pressure drops across both the material bed (ΔpB) and the distributor plate (ΔpD) were influenced by several factors, including distributor plate configuration, number of bubble caps, and bed material density. Additionally, the pressure drops across the material bed decreased as its mass decreased due to increased gas flow velocity. In hot operating conditions, the bubble cap configuration facilitated easier particle movement due to increased pressure, thus requiring less pressure. Both triangular and sintered bubble cap configurations with the largest number of holes and optimal pitch distance to the distributor surface area were found to be effective.
Ethical Dimensions of Clinical Data Sharing by U.S. Health Care Organizations for Purposes beyond Direct Patient Care: Interviews with Health Care Leaders
Authors: Jackson Brian R. , Kaplan Bonnie , Schreiber Richard , DeMuro Paul R. , Nichols-Johnson Victoria , Ozeran Larry , Solomonides Anthony , Koppel Ross
Published: October 2024

Objectives This study aimed to (1) empirically investigate current practices and analyze ethical dimensions of clinical data sharing by health care organizations for uses other than treatment, payment, and operations; and (2) make recommendations to inform research and policy for health care organizations to protect patients' privacy and autonomy when sharing data with unrelated third parties.

Methods Semistructured interviews and surveys involving 24 informatics leaders from 22 U.S. health care organizations, accompanied by thematic and ethical analyses.

Results We found considerable heterogeneity across organizations in policies and practices. Respondents understood “data sharing” and “research” in very different ways. Their interpretations of these terms ranged from making data available for academic and public health uses, and to health information exchanges; to selling data for corporate research; and to contracting with aggregators for future resale or use. The nine interview themes were that health care organizations: (1) share clinical data with many types of organizations, (2) have a variety of motivations for sharing data, (3) do not make data-sharing policies readily available, (4) have widely varying data-sharing approval processes, (5) most commonly rely on Health Insurance and Portability and Accountability Act (HIPAA) de-identification to protect privacy, (6) were concerned about clinical data use by electronic health record vendors, (7) lacked data-sharing transparency to the general public, (8) allowed individual patients little control over sharing of their data, and (9) had not yet changed data-sharing practices within the year following the U.S. Supreme Court 2022 decision denying rights to abortion.

Conclusion Our analysis identified gaps between ethical principles and health care organizations' data-sharing policies and practices. To better align clinical data-sharing practices with patient expectations and biomedical ethical principles, we recommend updating HIPAA, including re-identification and upstream sharing restrictions in data-sharing contracts, better coordination across data-sharing approval processes, fuller transparency and opt-out options for patients, and accountability for data-sharing and consequent harms.
Predicting Progressive Hemorrhagic Injury Following Traumatic Brain Injury by the Evaluation of D-Dimer/Fibrinogen Ratio
Authors: Patidar Akshay , Chaudhary Anurag , Sharma Vinod , Gupta Ashok
Published: October 2024

Background Prognosis of traumatic brain injury (TBI) significantly depends on the incidence of progressive hemorrhagic injury (PHI). The present study was conducted to assess whether D-dimer/fibrinogen ratio can predict PHI among the patients with TBI.

Materials and Methods A total of 150 patients were included in this retrospective study; among them 72 had PHI and 78 did not have PHI. Demographic, clinical, radiological, and laboratory parameters including plasma D-dimer and plasma fibrinogen levels and subsequently D-dimer/fibrinogen ratio were evaluated. Independent t-test, Mann–Whitney U test, chi-square test, Fisher's exact test, and multivariate logistic regression were used for statistical analysis.

Results Age, injury time, first computed tomography time, Glasgow Coma Scale scores, unreactive pupils, abnormal cisterns, midline shift above 5 mm, skull base fracture, epidural hematoma, subdural hematoma, intraventricular hemorrhage, cerebral hematoma, brain contusion, plasma D-dimer concentration, plasma fibrinogen concentration, and D-dimer/fibrinogen ratio vary significantly between PHI and non-PHI groups (p < 0.05). Multivariate logistic regression showed that the Glasgow Coma Scale score (odds ratio [OR], 0.531; 95% confidence interval [CI], 0.436–0.648; p = 0.004) and D-dimer/fibrinogen ratio (OR, 3.784; 95% CI, 2.086–6.867; p = 0.027) were the two independent predictors for PHI.

Conclusion D-dimer/fibrinogen ratio is a useful parameter in predicting the incidence of PHI among the patients with TBI.
Cost-Effective, Patient-Centric, and Innovative Repurposing of a Broken Lingual Arch Space Maintainer: A Case Report
Authors: Saha Swagata , Ajgaonkar Siddhesh , Kamath Namitha P. , Raman Nair Manju , Shetty Amarshree A.
Published: October 2024

Introduction Premature loss of primary teeth due to caries or trauma can cause space discrepancies leading to malocclusion and other dental issues. Space maintainers are essential for preserving the arch space until the eruption of the permanent teeth. This case report presents an innovative modification of an existing space maintainer to address clinical challenges, improve patient outcomes, and reduce costs.

Case Report An 8-year-old female presented with a broken lingual arch space maintainer impinging on the lingual mucosa. Clinical examination revealed nonrestorable teeth 84 and 75 that required extraction. Radiographs showed tooth 34 erupting soon and tooth 45 delayed. Owing to financial constraints, the existing appliance was modified by lingually cutting and adapting the wire to the distal surface of the canine. The appliance was cemented using Type I Glass Ionomer Cement in a single visit. After 6 months, tooth 35 erupted normally, without impaction.

Conclusion This case demonstrates the effectiveness of modifying existing space maintainers to provide cost-effective patient-centric solutions in pediatric dentistry.
Arthroscopic Suture Anchor Scapholunate Capsulodesis
Authors: Chung Sze Ryn , Carratalá Vicente , Delgado Pedro J. , Kalapos Robert , Kakar Sanjeev
Published: October 2024

Background: A retrospective review was performed of 15 adult patients who underwent arthroscopic suture anchor scapholunate capsuloligamentous repair between 2021 and 2023.

Patient/Methods/Results: There were 12 male and 3 female patients, with a mean age of 44.9 years. Eight patients had European Wrist Arthroscopy Society (EWAS) II (Geissler II), four patients had EWAS IIIC (Geissler III), and three patients had EWAS IV (Geissler IV). After a follow-up of 12 months (12–26), the mean grip strength significantly improved by 131% compared with presurgery. There was a significant improvement in the visual analog scale score from 6 to 1.2, the Mayo Wrist Score from 43.5 to 86.5, and the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire score from 65.9 to 6.5. Two EWAS IV patients had recurrent symptomatic scapholunate diastasis requiring scapholunate ligamentoplasty.

Conclusion: The arthroscopic dorsal scapholunate capsuloligamentous repair with suture anchors is a reliable and safe technique with minimal complications. It is recommended for reducible acute or chronic injury to the scapholunate ligament complex with suspected avulsion injury.

Level Of Evidence: Level IV
Spontaneous Rupture of Prenatally Detected Thoracic Neurenteric Cyst: Case Report and Review of Literature
Authors: Paradkar Priyanka Vishvanath , Redishetty Saritha , Vavilala Suseela
Published: October 2024

Neurenteric cysts are usually associated with vertebral anomalies of the same segments of vertebrae. Rarely, they can be detected antenatally. The prognosis depends upon the size and site of the lesion. In cases of small cysts with minimal mass effect, the prognosis is good. Larger cysts, however, can cause hydrops fetalis and, if untreated, can lead to intrauterine fetal demise. The present case report describes the successful conservative management of the neurenteric cyst detected prenatally and is accompanied by a summary from literature.
Case Report and Literature Review: A Severe Case of Blast-Related Traumatic Brain Injury
Authors: Lee Wei Lun , Alias Azmi , Lim Mei Sin
Published: October 2024

Blast-related traumatic brain injuries (bTBIs), once considered the signature wound of wars, have increasingly affected civilian populations due to the rise in terrorist attacks and industrial accidents. These injuries are complex, resulting from a combination of primary blast effects, secondary projectiles, tertiary impacts, and quaternary injuries from burns and toxic gas inhalation. Understanding the clinical presentation, management strategies, and outcomes of bTBIs is essential for enhancing patient care and improving prognosis. We report a case of industrial-related severe bTBI with opened depressed skull fracture and intracranial hematoma. The patient underwent decompressive craniectomy and evacuation of clot but postoperatively had a stormy recovery and multiple complications. He eventually succumbed due to his complications. This underscores the complexity of bTBIs and highlights the importance of a multidisciplinary approach in the management of bTBIs. Further research is needed to optimize treatment protocols and rehabilitation strategies for individuals with bTBIs.
Development of a compact magnetic spectrometer for use at the OMEGA Laser Facility and the National Ignition Facility
Authors: Pearcy J. A. , Russell L. , Kabadi N. V. , Johnson T. M. , Adrian P. A. , Gatu-Johnson M. , Casco E. , Palmisano K. , Gates G. , Burgett T. , Scott M. , Petrasso R. D. , Li C. K. , Frenje J.
Published: October 2024

Measurement of proton spectra is an important diagnostic for a variety of high energy density physics experiments. Current diagnostics are either not designed to capture the spectrum of low-energy protons or are unsuitable for high debris experiments. To bridge the gap, a new CR-39 based compact magnetic spectrometer (MagSpec) has been developed to measure proton spectra in the 1–20 MeV energy range, with a particular focus on the low-energy (1–6 MeV) spectrum, for use in experiments at the OMEGA Laser Facility and the National Ignition Facility (NIF). In the MagSpec diagnostic, protons of different energies are dispersed as they pass through a magnetic field before impinging on a differentially filtered CR-39 surface, resulting in a spatial distribution of CR-39 tracks that corresponds to the energy spectrum. In this paper, we discuss details of the design and implementation of MagSpec on the NIF and OMEGA.
Thermal-stimulated phase transition of vanadium dioxide enabling versatile transduction and smart applications
Authors: Zhou Yushan , Su Shanqian , Zhu Ziying , Hou Dibo , Zhang H. , Cao Yunqi
Published: October 2024

Vanadium dioxide (VO2) as a typically strongly correlated material has an attractive near-room-temperature metal–insulator transition (MIT). This transition shifted between metallic rutile and insulating monoclinic phases can be reversed by external thermal stimulation, accompanied by alterations in the lattice structure and electronic energy band structure, which bring about drastic changes in optical, electrical, thermal, and mechanical properties. Based on these unique characteristics, the VO2-integrated element can be utilized in the versatile transduction that converts indirect measurable factors into detectable physical quantities, representing a leap forward in sensing technology and facilitating the development of advanced systems toward an unprecedented level of sensitivity and responsiveness. In this perspective, we review the multifunctional advantages of VO2, driven by its thermally induced MIT, which transforms its crystal and electronic structures, leading to changes in optical, electrical, thermal, and mechanical properties. Our paper highlights that VO2 can serve as a high-performance transduction element, leveraging its attractive properties to facilitate the conversion of various variations into measurable signals, thereby enabling diverse advanced applications. To maximize the advantages of VO2, we identify the key challenges and opportunities related to this material, offering guidance and recommendations for future research directions.
Angle-dependent interlayer exchange coupling in all-electric perpendicular magnetization switching
Authors: Wang Weiyang , Lan Xiukai , Deng Yongcheng , Sheng Yu , Wen Hui , Ji Yang , Wang Kaiyou
Published: October 2024

Spin–orbit torque (SOT)-induced deterministic control of the magnetization in ferromagnets with perpendicular magnetic anisotropy (PMA) is key to next-generation spintronic applications. However, the tunability of SOT-induced switching still requires further exploration. Here, we investigated the angle-dependent interlayer exchange coupling on all-electric magnetization switching in a Co/Pt/Co trilayer, where the two Co layers exhibit PMA and in-plane magnetic anisotropy, respectively. After pre-magnetizing the in-plane Co layer, all-electric magnetization switching was achieved through interlayer exchange coupling. By changing the pre-magnetization direction, the out-of-plane SOT efficiency in the Co/Pt/Co device can be modulated, which depends on the x-component of the interlayer exchange coupling field. Additionally, a proportional variation in the magnitude of magnetization switching was observed, which corresponds to different current-induced out-of-plane effective fields. Such modulation of SOT switching is attributed to angle-dependent interlayer exchange coupling, which could be important for developing spin devices with enhanced tunability.
Numerical simulation of turbulent Taylor–Couette flow with high Taylor number and large radius ratio in high-speed canned motor pump internals
Authors: Zhang Yuhan , Xu Rui , Song Yuchen , Wu Dazhuan , Wu Peng
Published: October 2024

Taylor–Couette flow with a high Taylor number and large radius ratio is widely present in fluid machinery, such as the internal clearance flow in a canned motor pump typically. Taylor–Couette flow with radius ratios from 0.934 to 0.977 and Taylor number from 107 to 1010 was investigated by numerical simulations. The results indicated that torque is positively correlated to radius ratio, while dimensionless torque is exponentially related to the Taylor number. Subsequently, the physical characteristics of the flow field were described by extracting statistical quantities such as the average azimuthal velocity profile, velocity fluctuations, and near-wall region analysis at four internal cylinder rotation frequencies and four radius ratios. The results revealed that increasing rotation frequency would increase velocity gradients near the wall, while higher radius ratios would produce more uniform velocity fluctuation distributions. In addition, near-wall profiles showed a constant shear force layer, while the logarithmic layer was affected by rotation frequency and radius ratio. The detailed analysis revealed that as the rotation frequency increased, the flow gradually transitioned to a turbulent state, intensifying the interaction between large and small vortex structures. The rotation speeds of Taylor vortices remained consistent across different radius ratios, with smaller scales and more numerous vortices observed at larger ratios. Smaller radius ratios led to more fine-scale vortex structures near the cylindrical wall, significantly impacting azimuthal velocity fluctuations. Finally, near-wall velocity streaks are presented to demonstrate their periodic nature and the relationship between high-speed and low-speed regions, as well as their interaction with the wall and changes with distance.
Band alignment of CoO(100)–water and CoO(111)–water interfaces accelerated by machine learning potentials
Authors: Hu Jin-Yuan , Zhuang Yong-Bin , Cheng Jun
Published: October 2024

Cobalt monoxide (CoO) nanomaterials have drawn attention for their remarkable photocatalytic water splitting without an externally applied potential or co-catalyst. The success of overall water splitting is due to the appropriate band edge positions of the catalyst, which span the redox potentials of water splitting. Typically, CoO nanomaterials possess complex morphologies, which consist of multiple active surfaces. As a result, the precise roles of the surfaces in the overall water-splitting process remain to be elucidated. In this work, we have undertaken a thorough investigation into the band alignments at the CoO(100)–water and CoO(111)–water interfaces using ab initio molecular dynamics and machine learning accelerated molecular dynamics simulations. The results of band alignment reveal that CoO(100) supports both the Hydrogen Evolution Reaction (HER) and the oxygen evolution reaction, whereas CoO(111) only facilitates the HER. Moreover, the variance in band positions between CoO(100) and CoO(111) results in an intrinsic potential difference, facilitating the migration of electrons toward CoO(100), while holes accumulate on CoO(111). The separation of photoexcited carriers effectively promotes water splitting in CoO.
On the bi-stability of flow around two tandem circular cylinders at a subcritical Reynolds number of 3900
Authors: Zeng Cheng , Hu Yudie , Zhou Jie , Wang Lingling
Published: October 2024

To investigate the characteristics of the bi-stable flow at subcritical Reynolds numbers, large eddy simulation is adopted to simulate the crossflow around two tandem circular cylinders at Re = 3900. The reattachment/co-shedding bi-stability is observed in the simulations with spacing ratios (L/D, L is the center-to-center cylinder spacing and D is the diameter) of 4.5 and 4.7. Statistical analyses are performed on the hydrodynamic coefficients, time-averaged flow fields, three-dimensional characteristics, wake pattern, and vortex shedding frequencies at different spacing ratio and time period. In addition, a detailed analysis and explanation were conducted on the secondary vortices identified in the reattachment flow regime, revealing that the secondary vortices, generated from the instability of the shear layer, significantly influence the variation in vortex shedding frequency over time. The reduced-order variational mode decomposition method is employed to decompose the flow field during the flow regime transitions, unveiling their spatial and temporal features. It is revealed that the shear layer instability and the low-frequency modulation behavior are the predominant factors triggering the bi-stable phenomenon at subcritical Reynolds numbers. This study aims to uncover triggering mechanisms underlying the bi-stable phenomenon in the flow around two tandem cylinders and provides valuable insight for relevant engineering applications.
Characterizing the onset of transitional and turbulent flow regimes in pipe flows using instantaneous time-frequency-based analysis
Authors: Shirdade Nikhil , Kolliyil Jibin Joy , El-Khader Baha Al-Deen T. , Brindise Melissa C.
Published: October 2024

Accurately identifying the onset of transitional and turbulent flow within any pipe flow environment is of great interest. Most often, the critical Reynolds number (Re) is used to pinpoint the onset of turbulence. However, the critical Re is known to be highly variable, depending on the specifics of the flow system. Thus, for flows (e.g., blood flows), where only one realization (i.e., one mean Re) exists, the presence of transitional and turbulent flow behaviors cannot be accurately determined. In this work, we aim to address this by evaluating the extent to which instantaneous time-frequency (TF)-based analysis of the fluctuating velocity field can be used to evaluate the onset of transitional and turbulent flow regimes. Because current TF analysis methods are not suitable for this, we propose a novel “wavelet-Hilbert time-frequency” (WHTF) method, which we validate herein. Using the WHTF method, we analyzed the instantaneous dominant frequency of three planar particle image velocimetry-captured pipe flows, which included one steady and two pulsatile with Womersley numbers of 4 and 12. For each case, data were captured at Re's spanning 800–4500. The instantaneous dominant frequency analysis of these flows revealed that the magnitude, size, and coherence of two-dimensional spatial frequency structures were uniquely different across flow regimes. Specifically, the transitional regime maintained the most coherent, but lowest magnitude frequency structures, while the laminar regime had the highest magnitude, lowest coherence, and smallest frequency structures. Overall, this study demonstrates the efficacy of TF-based metrics for characterizing the progression of transition and turbulent flow development.
Studying the impact of pore sizes on gas flow and distribution in volatile carbonate reservoirs using a new triple-porosity model
Authors: Jia Pin , Guo Hongxin , Gao Hongda
Published: October 2024

Carbonate reservoirs exhibit varying pore sizes that significantly impact gas distribution and flow dynamics. Current models fail to adequately address the flow mechanisms within the diverse matrix pores of carbonate reservoirs. To address this gap, we propose a triple-porosity model that incorporates small pores, large pores, and fractures, alongside a capillary pressure equation that accounts for pore radius and saturation. Additionally, a new transient shape factor was derived. Utilizing the triple-porosity model, we investigated the processes of gas separation and dissolution from oil, gas distribution, and the effects of gas on water flow. Our findings reveal that gas is primarily dissolved during the initial water injection stage or at low gas saturation levels. Once the pressure reaches the gas initiation threshold, gas transport becomes the dominant mechanism. Both dissolution and transport can reduce gas saturation by a factor of 1:10. In small pores, capillary pressure induces a gas locking phenomenon, resulting in higher free gas presence compared to large pores. Moreover, the presence of the gas phase accelerates the spread of injected water. Implementing depletion followed by water injection decreases oil recovery. This study elucidates the processes of gas separation, distribution, flow, and dissolution, providing theoretical guidance for managing complex flow dynamics in volatile carbonate reservoirs.
On the intense sensitivity to wall convergence of instability in a channel
Authors: Kumar Anup , Govindarajan Rama
Published: October 2024

The classical Jeffery–Hamel flow at small wall convergence has received less attention than it should and is the subject here. While laminar flow through a plane channel displays only a parabolic velocity profile, for even small convergence angles, the Jeffery–Hamel equations display a variety of non-unique laminar flow solutions at a given Reynolds number. Three such solutions are shown to be stable at low Reynolds number and could possibly be attained in the experiment. Multiple critical layers can occur, and dissipation need not attain a maximum at the wall. In the one-lobed velocity profile, the critical Reynolds number for the first instability is known [K. Fujimura, J. Phys. Soc. Jpn. 51, 2000–2009 (1982); M. R. Jotkar and R. Govindarajan, Phys. Fluids 29, 064107 (2017)] to be an extremely sensitive function of the wall tilt angle, and we show that this is because the dominant balance in the critical layer is different from the traditional one in a plane channel. Finally, a direct analogy to divergent pipe flow is drawn.
Dynamics of quantum turbulence in axially rotating thermal counterflow
Authors: Dwivedi R. , Dunca T. , Novotný F. , Talíř M. , Skrbek L. , Urban P. , Zobač M. , Vlček I. , Varga E.
Published: October 2024

Generation, statistically steady state, and temporal decay of axially rotating thermal counterflow of superfluid 4He (He II) in a square channel is probed using the second sound attenuation technique, measuring the density of quantized vortex lines. The array of rectilinear quantized vortices created by rotation strongly affects the development of quantum turbulence (i.e., turbulence strongly affected by the presence of quantized vortices). At relatively slow angular velocities, the type of instability responsible for the destruction of the laminar counterflow qualitatively changes: the growth of seed vortex loops pinned on the channel wall becomes gradually replaced by the growth due to Donnelly–Glaberson instability, which leads to rapid growth of helical Kelvin waves on vortices parallel with applied counterflow. The initial transient growth of vortex line density that follows the sudden start of the counterflow appears self-similar, linear in dimensionless time, Ωt. We show numerically that Kelvin waves of sufficiently strong amplitude reorient the vortices into more flattened shapes, which grow similarly to a free vortex ring. The observed steady state vortex line density at sufficiently high counterflow velocity and its early temporal decay after the counterflow is switched off are not appreciably affected by rotation. It is striking, however, that although the steady state of rotating counterflow is very different from rotating classical grid-generated turbulence, the late temporal decay of both displays similar features: the decay exponent decreases with the rotation rate Ω from −3/2 toward approximately −0.7, typical for two-dimensional turbulence, consistent with the transition to bidirectional cascade.
Solid particle-induced flow in a cavity with slip-spin sphere surfaces
Authors: Salem Ahmed G.
Published: October 2024

A quasi-steady flow due to a solid sphere moving in a micropolar fluid inside a concentric cavity is analyzed, where on the particle's external surface and the cavity's internal surface, the fluid can slip-spin. The solid particle translates upon the diameter connecting their centers when the Reynolds numbers are low. A general solution, to resolve the Stokesian equations for the fluid velocity field, is obtained according to the spherical coordinates, depending on the concentric position between the particle and cavity. Boundary conditions are satisfied, on the particle's external surface and the cavity's internal surface. Moreover, a tangential couple stress is used on both surfaces. The normalized drag force affecting a translating particle is determined to be a function that increases monotonically for the ratio of the solid-to-cavity radii, becoming infinite when the particle surface touches the cavity surface. Numerical outcomes for the normalized force affecting the particle's surface are gained at different values for the ratio of the particle-to-cavity radii and also the slip-spin surface coefficients of the particle and cavity. Our outcomes are in a high level of precision with the solutions available in the literature. The current study is significant for the domains of industrial, natural, biological, and medical processes, like the production of raindrops, the flow of blood cells in arteries and veins, sedimentation, coagulation, suspension rheology, and liquid–liquid extraction.
Influence of a nonuniform magnetic field on the flow and heat transfer of a thermosensitive ferrofluid
Authors: Castro L. H. F. , Oliveira T. F. , Rosa A. P.
Published: October 2024

In this work, we numerically investigate how a nonuniform magnetic field affects the flow and heat transfer in a bottom-heated closed enclosure filled with a thermosensitive ferrofluid. Under the simultaneous action of the gravitational and external magnetic field, a complex flow develops inside the cavity. We change the intensity of the external magnetic field aiming to understand how the flow field, temperature distribution, and net heat transfer are affected. Our findings reveal that the magnetic field has a significant influence on the topology of the flow and temperature fields, consequently impacting the overall heat transfer. It is possible to use the magnetic field generated by a conducting wire to change the net heat transfer through the cavity. We found that the average Nusselt number is a growing function of the magnetic field intensity, except for a specific Rayleigh number. Furthermore, we recognize non-stationary regimes at intermediate magnetic Rayleigh numbers, associated with unstable topological transitions in the flow pattern induced by the magnetic field. Consequently, we uncover flow regimes characterized by steady boundary conditions but exhibiting periodic flow and heat transfer patterns. Additionally, we observe that the unsteady topological transitions are suppressed by high magnetic Rayleigh numbers, resulting in steady flow.
Numerical modeling and analysis of stable levitation and flexible deformation for lithium-ion battery electrodes
Authors: Ye Xin , Liu Xijiang , Lu Qian , Wu Lutong , Jiang Fengze
Published: October 2024

Suspension drying, a non-contact drying method, enables simultaneous drying on both sides of the electrodes, thereby meeting the demand for efficient and high-quality production. This study introduces a fluid–structure coupling simulation model, developed based on force balance analysis during the suspension drying process. The model is designed to explore the parameters that facilitate stable levitation at the equilibrium position. Further investigation, based on the conditions for stable electrode levitation, examines the factors influencing the extent of flexible deformation in the electrodes. The results indicate that to achieve stable suspension during drying, the fluid flow rate at the lower nozzle must exceed that at the upper nozzle by about 6.5% to balance the load on the electrodes. Notably, when the coating areal density is increased from 100 to 500 g/m2, a corresponding increase in the lower nozzle wind speed is required to maintain equilibrium. Moreover, a predictive relational equation has been established for the maximum flexible deformation of the electrode in the y-direction under various working conditions and tensile forces. Specifically, at an areal density of 200 g/m2, a tensile force exceeding 70.00 N is sufficient to limit the maximum deformation to less than 6.00 mm, thus preventing nozzle contact and defects. This equation provides valuable theoretical guidance for the practical application of stable suspension drying in lithium-ion battery electrode manufacturing, facilitating process optimization and enhancing product quality.
Trap-induced electrical degradation in edge-termination-hardened NiO/β-Ga2O3 heterojunction under 10 MeV fluence-dependent proton irradiations
Authors: Zhang Z. L. , Sun N. , Wang T. Q. , Zhou F. , Liu C. M. , Qi C. H. , Ma G. L. , Zhang Y. Q. , Li H. Y. , Lei Z. F. , Ye J. D. , Lu H. , Huo M. X. , Xiao L. Y.
Published: October 2024

Ultrawide bandgap beta-phase gallium oxide (β-Ga2O3) power devices have great potential in irradiation applications, yet the instability of their electrical performance induced by irradiation remains under investigation. This work examines the degradation of electrical performance in edge-termination-hardened nickel oxide (NiO)/β-Ga2O3 heterojunction p–n diodes (ETH-HJDs) subject to 10 MeV proton irradiation across a wide fluence range of 1011–1013 p/cm2. The results reveal interface and bulk trap-induced degradation with intriguing non-monotonic variations in forward conduction and reverse leakage currents—initially increasing and then decreasing with increased irradiation fluences. This abnormal phenomenon is unlikely due to irradiation-induced edge damage as the ETH design was implemented. Forward I–V curve modeling showcases an aggravated series resistance effect after irradiation, with the ideality factor rising from 1.07 to 1.24, indicating deteriorated interface properties. Capacitance–voltage (C–V) characterizations suggest that bulk traps caused by irradiation impact the carrier removal effect, evidenced by a carrier removal rate of 1070 cm−1 at a high proton fluence of 1 × 1013 p/cm2. Furthermore, deep-level transient spectroscopy reveals four distinct types of traps distributed at the interface or within Ga2O3 bulk contributing to the device leakage. These findings offer critical insights into the instability of electrical characteristics in high-performance NiO/β-Ga2O3 HJDs under proton irradiation.
Collision integrals for N+–N+, O+–O+, and N+–O+ interactions in air plasmas
Authors: Ding Zi , Liu Linhua
Published: October 2024

Ion–ion collisions play a crucial role in determining transport coefficients in the atmosphere of Earth. This study investigated collision integrals for N+(3P)–N+(3P,1D), O+(4S)–O+(4S, 2D), and O+(4S)–N+(3P, 1D) interactions based on the classical approach and real potentials in the temperature range of 1000–50 000 K. Accurate potential energy curves (PECs) are calculated by state-averaged complete active space self-consistent field and internally contracted multireference configuration interaction methods, employing the aug-cc-pwCV5Z-DK basis set with reasonable extrapolation. Moreover, this study considered the diabatic path to construct the PEC when the avoided crossings occur since the diabatic path is easier to follow. PECs for N+(3P)–N+(1D), O+(4S)–O+(2D), and O+(4S)–N+(1D) interactions and collision integrals based on the high-quality ab initio points for these interactions are investigated for the first time. This work aims to provide reliable data for predicting the transport properties for modeling the air plasma flow field.
Quantum algorithm for nonlinear Burgers' equation for high-speed compressible flows
Authors: Esmaeilifar Esmaeil , Ahn Doyeol , Myong Rho Shin
Published: October 2024

Recent advances in quantum hardware and quantum computing algorithms promise significant breakthroughs in computational capabilities. Quantum computers can achieve exponential improvements in speed vs classical computers by employing principles of quantum mechanics like superposition and entanglement. However, designing quantum algorithms to solve the nonlinear partial differential equations governing fluid dynamics is challenging due to the inherent linearity of quantum mechanics, which requires unitary transformation. In this study, we first address in detail several challenges that arise when trying to deal with nonlinearity using quantum algorithms and then propose a novel pure quantum algorithm for solving a nonlinear Burgers' equation. We employed multiple copies of the state vector to calculate the nonlinear term, which is necessary due to the no-cloning theorem. By reusing qubits from the previous time steps, we significantly reduced the number of qubits required for multi-step simulations, from exponential/quadratic scaling in earlier studies to linear scaling in time in the current study. We also employed various advanced quantum techniques, including block-encoding, quantum Hadamard product, and the linear combination of unitaries, to design a quantum circuit for the proposed quantum algorithm. The quantum circuit was executed on quantum simulators, and the obtained results demonstrated excellent agreement with those from classical simulations.
Effects of grass-shrub vegetation and litter on overland flow resistance coefficients
Authors: Yang Chenxin , Sun Xiaomin , Yang Qingjun , Cen Youdong , Liu Chenglong , Wei Shue , Zhang Kuandi
Published: October 2024

Vegetation communities can drastically influence the hydrodynamic characteristics of the overland flow, change the overland flow resistance mechanism, and regulate soil erosion. To investigate the effect of grass-shrub vegetation and litter combinations on overland flow resistance, simulated rainfall experiments were carried out. The experiments involved a 15° gradient slope, five rainfall intensities (I = 60–120 mm h−1), five grass-shrub coverages (Cgs), and six litter volumes (Cl). The results showed that the mean values of form resistance under Cgs = 15%–75% ranged from 0.195 to 1.775, and the mean values of form resistance under Cl = 5–25 g m−2 ranged from 0.609 to 2.160. The form resistance of grass-shrub slopes with the addition of litter was 1.82–12.47 times higher than that under a single grass-shrub cover. The order of magnitude of the factors influencing the slope form resistance coefficients of the grass-shrub + litter was Cl > Cgs > Cl × Cgs > I. With varying vegetation kinds and coverage rates, I had diverse effects on form resistance. The resistance superposition principle does not hold under combined vegetation cover conditions. The degree of difference (Δfform) in form resistance was inversely proportional to I and directly proportional to Cl. Through dimensional and multiple nonlinear regression analyses, a general model for calculating form resistance was established (Adj. R2 = 0.99, NSE = 0.97). Theoretically, the results of this study can be used to evaluate soil and water conservation during vegetation community succession and restoration.