bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Socioscientific Issues (SSI) Approach on Students’ Creative Thinking Skills in Disaster Mitigation Material
Authors: Diana Nirva , Irwandani  , Sukron M. Miftahul , Akbar M. Fadilah , Latifah Sri , Susilowati Nur Endah
Published: January 2024

This study investigates the influence of the Socioscientific Issues (SSI) approach on enhancing creative thinking abilities among vocational school students. This research utilized a quasi-experimental method with a Non-equivalent Control Group design. The study’s population comprised vocational school students in Metro City, Lampung. Sampling was conducted using a purposive sampling technique with 60 students divided into two groups: an experimental and a control class. The research focused on disaster mitigation as its subject matter. Findings revealed an average N-gain value of 0.56 for the experimental class, whereas the control class achieved a value of 0.44. These results signify the impactful influence of the SSI approach on students’ creative thinking skills, particularly in addressing disaster-related issues.
Smartphone Addiction Screening Application Development Based on Android: A Preeliminary Study
Authors: Hatmanti Nety Mawarda , Septianingrum Yurike , Fitriasari Andikawati , Martining Wardani Erika , Setiyowati Eppy
Published: January 2024

The growing and increasing pattern of smartphone use in life from just a communication tool to an entertainment tool makes someone use a smartphone excessively. Excessive use of smartphones if not addressed immediately can have an impact on various disorders ranging from physical, psychological and social disorders. The purpose of this study was to produce an Android-based smartphone addiction screening application and to describe the quality of an Android-based smartphone addiction screening application. This research belongs to the type of Research & Development (R&D). The model used is the Dick & Carey model where the implementation of the developer includes data collection, planning and product development stages. At the data collection stage, 3 (three) were obtained, namely data on family members, smartphone use and complaints experienced and the smartphone addiction scale short version (SAS-SV) questionnaire. In the second stage, namely planning, researchers began to incorporate into an android-based application and develop it to be able to draw conclusions from filling out the questionnaire. Conclusions from filling in include demographic data, physical, psychological and social complaints and dependency categories. It is hoped that this application can be tested on the community, especially families, to measure the validity and reliability and then use it as an online measuring tool.
Analysis of Teaching Competence Science Teachers in Using Multimedia at Junior High School
Authors: Bangun Karla Sandriani , Gunawan Indra , Yusandika Ajo Dian , Diani Rahma
Published: January 2024

This study aims to measure the professional competence of science teachers in using multimedia, particularly power point and learning applications. This research utilized a quantitative descriptive approach with a survey method. The study was conducted in six public junior high schools in the Tulang Bawang Tengah District, namely SMPN 6 Tulang Bawang Barat, SMPN 7 Tulang Bawang Barat, SMPN 8 Tulang Bawang Barat, SMPN 9 Tulang Bawang Barat, SMPN 11 Tulang Bawang Barat, and SMPN 12 Tulang Bawang Barat. The sample consisted of 19 science teachers from these schools. Data were collected through questionnaires and interviews with science teachers, as well as distributing questionnaires to students to support the research results for greater objectivity. The data obtained were analyzed using percentage formula for data analysis. The results of the study showed that the level of professional competence of science teachers in using multimedia is 69%. It can be conclude that science teacher have teaching competence in using multimedia at a high level.
Nuanced Statistics E-Module Development Islam and the Environment
Authors: Janah L.M. , Putra R.W.Y. , Nasution S.P. , Putra Fredi Ganda
Published: January 2024

The aim of this research and development is to create a statistical e-module infused with islamic elements and an environmental context, providing a resolution to students’ challenges in comprehending statistical material while concurrently enriching their understanding of the correlation between statistical concepts and islamic principles within the environmental framework. Employing the research and development (r&d) method, the study utilizes the addie model, comprising distinct phases of analysis, design, development, implementation, and evaluation. The study encompasses middle school students in central lampung and mts students in central lampung as its participants. Data collection methods involve interviews, validation questionnaires, product attractiveness evaluations, and test questions. Expert assessments categorize the e-module as “very eligible” in terms of its material and media components, with religious experts also endorsing its eligibility with a “very eligible” rating. Small-scale attractiveness trials reveal an “interesting” rating for middle school students and a “very interesting” rating for mts students. In large-scale attractiveness tests, both middle school and mts students show consistent “very interesting” ratings. Effectiveness tests unveil a “moderate” score for middle school students and a “medium” score for mts, signifying the e-module’s overall effectiveness in enhancing statistical comprehension. In conclusion, the developed statistics e-module, incorporating islamic nuances and an environmental perspective, demonstrates commendable feasibility, captivating appeal, and efficacy for educational implementation.
Development of Science Learning Videos with the Canva Application on Socioscientific Issues Content
Authors: Jatmiko Agus , Armita Netty , Irwandani  , Saputro Trimo , Aridan Muhammad
Published: January 2024

The purpose of this study was to determine the feasibility and practicality of science learning videos with the Canva application on socioscientific issues content. The type of research used is research and development. The development model used in this study uses the model developed by Dick and Carry, namely the ADDIE development model. The ADDIE development model includes analyze, design, develop, implement, and evaluate. Products that have been developed will then be assessed for feasibility by material and media experts. After being tested for feasibility and going through the revision stage, the product developed was tested on students. The subjects of this research trial were science and social subject educators and class X students of SMKN 2 Metro. The instrument used in this study was a questionnaire sheet using a stepped scale (Likert scale) with 5 assessment categories. The results of the study show that the learning videos developed are very suitable for use in learning to support the learning profile of Pancasila with a score of 89.53% by media experts, including in the very feasible category and 80% by material experts, including in the appropriate category.
Development of Web-Based Audio-Visual Media for Fi’il Amr for Beginners Learning at Ma’had al-Jami’ah UIN Raden Intan Lampung
Authors: Mizan A.N. , Hijriyah U. , Famela Z.I. , Dinata R.S. , Wahidah Y.L. , Mardian H.
Published: January 2024

This research is motivated by the lack of development of web-based audiovisual media for the “fi’il Amr” material in Arabic language learning. The aim of this research is to develop a web-based audiovisual media for the “fi’il Amr for beginners” material and to assess its feasibility. This study is an R&D (Research and Development) study that adopts the Borg & Gall development model. The research subjects are the students of Ma’had al-Jami’ah UIN Raden Intan Lampung. The data collection instrument is a questionnaire validated by language experts, content experts, and educators at Ma’had al-Jami’ah UIN Raden Intan Lampung. To assess the quality of the web-based audiovisual media, a questionnaire was administered to gather student responses towards the website. The resulting data is qualitative and analyzed using evaluation criteria guidelines to determine the quality of the developed web-based audiovisual media. This research has produced a product in the form of a web-based audiovisual media for the “fi’il amr for beginners” material. According to language experts, it received a percentage of 3.35, categorized as very interesting. Media experts evaluated it and gave it a percentage of 3.75, also categorized as very interesting. The assessment from educators at Ma’had al-Jami’ah UIN Raden Intan Lampung resulted in a percentage of 3.57, categorized as very interesting. As for student responses, in the small-scale trial, it received a percentage categorized as interesting. In the field trial, it received a percentage of 3.56, categorized as very interesting.Page layout
The Effect of the Think-Pair-Share Learning Model Assisted by Augmented Reality Media on the Critical Thinking Skills of Class XI Students of SMA Negeri 1 Sumberjaya
Authors: Oktafiani Raicha , Suci Enggitia Wulan , Kesumawardani Aryani Dwi , Salsabila  , Puspitasari Nina Ayu
Published: January 2024

This research was motivated because it found problems in learning activities, students felt bored and tended to be less active. This problem results in students’ critical thinking skills are still relatively low. The purpose of this study was to determine the influence of the Think-Pair-Share learning model assisted by Augmented Reality media on students’ critical thinking skills. The research method used was Quasi experiment with pretest postest only control group design. The research samples were class XI IPA 1 as an experimental class and class XI IPA 3 as a control class taken with the Cluster technique. Data collection using critical thinking skills tests. Test the hypothesis using the t test and a significance of 0.05. The results of the analysis obtained a value of 0.000 < 0.05 so that it can be said that H0 is rejected and Ha is accepted. Based on the results of the study, it can be concluded that there is an influence of the Think-Pair-Share learning model assisted by Augmented Reality learning media on the critical thinking ability of students.
Internet of Things to realize Education in Industry 4.0 based on Sustainability Environment
Authors: Kesuma Mezan el-Khaeri , Kesuma Guntur Cahaya , Taher Andi
Published: January 2024

This study discusses how IoT can be applied in the educational environment from the perspective at the level: campus managers, educators, and learners to provide sustainable intelligent education and what are the main challenges in implementing IoT in the educational environment, especially the campus at the State Islamic University of Raden Intan Lampung. This study uses a mixed method of literature studies and field survey studies. In the opportunities and challenges in implementation at the Campus of the State Islamic University of Raden Intan Lampung consist of 3 main fields: Education, Agriculture-Fisheries and Environment, Energy etc. Implementing IoT is expected to realize a Smart, Environmentally Friendly and Sustainable Campus. So that it will significantly improve the sustainability of resources using IoT in the future.
Eine gewaltige Stimme
Authors: Stark Dominik
Published: January 2024

In Nordrhein-Westfalen nehmen die Pflegefachpersonen ihre Zukunft selbst in die Hand. Nach Gründung der Pflegekammer NRW im Jahre 2022, startete die erste Legislaturperiode im vergangenen Jahr so richtig durch.
Auch online zählt Wahrhaftigkeit
Authors: Albrecht Andrea
Published: January 2024

Weniger heile Welt, mehr Transparenz: Eine Studie hat untersucht, wie Kliniken die größten Chancen haben, potenzielle neue Mitarbeiter online auf sich aufmerksam zu machen.
Retrosynthetic Simplicity
Authors: Levin Mark D.
Published: January 2024

Retrosynthetic simplicity is introduced as a metric by which methods can be evaluated. An argument in favor of reactions which are retrosynthetically simple is put forward, and recent examples in the context of skeletal editing from my own laboratory as well as contributions from others are analyzed critically through this lens.

1 Introduction

2 Example 1: Quinoline to Quinazoline (One Product, Two Starting Materials)

3 Example 2: Benzene to Pyridine (Two Products, One Starting ­Material)

4 Caveats, Counterarguments, and Conclusions
Co-production of privately owned public space: Who, why, when, and how?
Authors: Lee Dahae , Scholten Nele
Published: January 2024

The term ‘co-production’ has been used in various fields, including planning, as collaborative forms of public goods and service delivery gain significance. Co-production has two sides—the ‘co’ side refers to actors and their motivations, while the ‘production’ side refers to phases and instruments. This paper examines privately owned public space/s (POPS) based on the two sides of co-production. Thereby, it addresses two research gaps. First, less has been written to date on the involvement of actors other than local authorities and developers. Second, little attention has been paid to the phase through which POPS are co-produced. The paper fills these research gaps by presenting the empirical work undertaken in HafenCity, Hamburg. It reveals a wide range of actors engaged in four different phases through various instruments. This paper also identifies challenges of co-production of POPS, and makes recommendations.
On self-similar patterns in coupled parabolic systems as non-equilibrium steady states
Authors: Mielke Alexander , Schindler Stefanie
Published: January 2024

We consider reaction–diffusion systems and other related dissipative systems on unbounded domains with the aim of showing that self-similarity, besides the well-known exact self-similar solutions, can also occur asymptotically in two different forms. For this, we study systems on the unbounded real line that have the property that their restriction to a finite domain has a Lyapunov function (and a gradient structure). In this situation, the system may reach local equilibrium on a rather fast time scale, but on unbounded domains with an infinite amount of mass or energy, it leads to a persistent mass or energy flow for all times; hence, in general, no true equilibrium is reached globally. In suitably rescaled variables, however, the solutions to the transformed system converge to so-called non-equilibrium steady states that correspond to asymptotically self-similar behavior in the original system.
Two types of universal characters and the integrable hierarchies
Authors: An Rui , Wang Na , Yan Zhaowen
Published: January 2024

In this paper, we propose two types of universal characters corresponding to partition shapes π = (3) and π = (2, 1) and construct their vertex operators realizations. It is proved that (3)-type and (2, 1)-type universal characters can be derived by the products of vertex operators acting on the identity. Furthermore, we investigate (3)-type and (2, 1)-type universal characters by means of Hamiltonian and fermions expectation values. In addition, based upon bilinear equations, we present the (3)-type and (2, 1)-type universal characters hierarchies whose τ functions can be derived from (3)-type and (2, 1)-type universal characters.
Existence and multiplicity results for parameter Kirchhoff double phase problem with Hardy–Sobolev exponents
Authors: Cheng Yu , Bai Zhanbing
Published: January 2024

The solvability of a class of parameter Kirchhoff double phase Dirichlet problems with Hardy–Sobolev terms is considered. We focus on the existence of at least one solution, two solutions, three solutions, and infinitely many solutions to the problem, as the nonlinear terms satisfy different growth conditions, respectively. Our tools are mainly based on variational methods and critical point theory. In particular, in order to establish the relationship between singular terms and the norm of the Musielak–Orlicz–Sobolev space, we extend the Sobolev–Hardy inequality from W01,p to W01,H.
Improvement of clinical wound microcirculation diagnosis using an object tracking-based laser speckle contrast imaging system
Authors: Hsieh Meng-Che , Chang Chia-Yu , Hsu Ching-Han , Lin Yan-Ren , Hsieh Pei-You , Ching Congo Tak-Shing , Liao Lun-De
Published: January 2024

Wound monitoring is crucial for effective healing, as nonhealing wounds can lead to tissue ulceration and necrosis. Evaluating wound recovery involves observing changes in angiogenesis. Laser speckle contrast imaging (LSCI) is vital for wound assessment due to its rapid imaging, high resolution, wide coverage, and noncontact properties. When using LSCI equipment, regions of interest (ROIs) must be delineated in lesion areas in images for quantitative analysis. However, patients with serious wounds cannot maintain constant postures because the affected areas are often associated with discomfort and pain. This leads to deviations between the drawn ROI and actual wound position when using LSCI for wound assessment, affecting the reliability of relevant assessments. To address these issues, we used the channel and spatial reliability tracker object tracking algorithm to develop an automatic ROI tracking function for LSCI systems. This algorithm is used to track and correct artificial movements in blood flow images, address the ROI position offset caused by the movement of the affected body part, increase the blood flow analysis accuracy, and improve the clinical applicability of LSCI systems. ROI tracking experiments were performed by simulating wounds, and the results showed that the intraclass correlation coefficient (ICC) ranged from 0.134 to 0.976. Furthermore, the object within the ROI affected tracking performance. Clinical assessments across wound types showed ICCs ranging from 0.798 to 0.917 for acute wounds and 0.628–0.849 for chronic wounds. We also discuss factors affecting tracking performance and propose strategies to enhance implementation effectiveness.
MOCVD-grown Ga2O3 thin films for polarization-sensitive infrared photonics
Authors: Dereshgi Sina Abedini , Lee Junhee , Ceneda Daniele , Larciprete Maria Cristina , Centini Marco , Razeghi Manijeh , Aydin Koray
Published: January 2024

The phonon modes of materials contain critical information on the quality of the crystals. Phonon modes also offer a wide range of polarization-dependent resonances in infrared that can be tailored to applications that require large dielectric function contrast in different crystal directions. Here, we investigate the far-field characteristics of MOCVD-grown Ga2O3 thin films. With a combination of cross-polarization FTIR and AFM characterization techniques, we propose an easy and non-invasive route to distinguish κ and β phases of Ga2O3 and study the quality of these crystals. Using numerical methods and cross-polarization spectroscopy, the depolarization characteristics of β-Ga2O3 are examined and depolarization strength values as high as 0.495 and 0.76 are measured, respectively, for 400 and 800 nm-thick β-Ga2O3. The strong birefringence near optical phonon modes of an 800 nm β-Ga2O3 on a sapphire substrate is used to obtain several polarization states for the reflected light in the second atmospheric window 8–14 µm. We anticipate that our findings open a new path for material characterization and wave plate design for the mid-IR range and offer novel possibilities for the future of IR on-chip photonics, thanks to the compatibility of β-Ga2O3 with standard nanofabrication technology.
On the improvement of smoothing by spectral dispersion efficiency for laser–plasma interaction
Authors: Fusaro A. , Collin R. , Riazuelo G. , Loiseau P. , Thauvin O. , Penninckx D.
Published: January 2024

Large energetic laser facilities provide an amazing tool for bringing matter into high energy density states but achieving a good energy conversion requires to optically smooth the high-power laser beams. Optical smoothing reduces the laser spatial and temporal coherences, allowing to mitigate the development of unwanted laser–plasma instabilities (LPI). Two schemes have been mainly developed: polarization smoothing and smoothing by spectral dispersion. Here, we focus on the latter. Smoothing by spectral dispersion consists in broadening the spectrum usually through a sinusoidal phase modulation and dispersing it with an optical grating. It is usually considered that the modulation frequency should be equal to the inverse of the time delay of the grating, because it maximizes the number of uncorrelated speckles patterns at a given bandwidth. However, current optical smoothing designs are still not sufficient for mitigating LPI. Because the optical smoothing system possesses degrees of freedom, we propose to improve the optical smoothing efficiency by a better tuning of those parameters. Considering the Laser Mégajoule optical system framework, we show that an increase in the modulation frequency allows a better efficiency of the smoothing while keeping the same bandwidth. We assess the efficiency by looking at a better mitigation of the stimulated Brillouin scattering that, due to its dangerousness in hohlraums developed for inertial confinement fusion applications in the indirect drive scheme, serves as a witness instability.
Sloshing of a two-layer fluid in a vertical cylinder of constant depth
Authors: Kuznetsov Nikolay G. , Motygin Oleg V.
Published: January 2024

Sloshing eigenvalues and eigenfunctions are studied for vertical cylinders of constant, finite depth occupied by a two-layer fluid. Two families of eigenfrequencies are obtained in the form expressing them explicitly via the eigenvalues of the Neumann Laplacian in the two-dimensional domain—the cylinder's cross section. Eigenfrequencies belonging to one of the families behave similar to those that describe sloshing in a homogeneous fluid, whereas the other family includes a large number of sufficiently small frequencies, provided the ratio of densities is close to unity. Various properties of eigenfrequencies are investigated for cylinders of arbitrary cross section; they include the dependence on the interface depth and the ratio of densities, and the asymptotics of the eigenvalue counting function. The behavior of eigenvalues and the corresponding eigenmodes is illustrated by numerical examples for circular cylinders without and with a radial baffle.
Fundamental patterns of signal propagation in complex networks
Authors: Hu Qitong , Zhang Xiao-Dong
Published: January 2024

Various disasters stem from minor perturbations, such as the spread of infectious diseases and cascading failure in power grids. Analyzing perturbations is crucial for both theoretical and application fields. Previous researchers have proposed basic propagation patterns for perturbation and explored the impact of basic network motifs on the collective response to these perturbations. However, the current framework is limited in its ability to decouple interactions and, therefore, cannot analyze more complex structures. In this article, we establish an effective, robust, and powerful propagation framework under a general dynamic model. This framework reveals classical and dense network motifs that exert critical acceleration on signal propagation, often reducing orders of magnitude compared with conclusions generated by previous work. Moreover, our framework provides a new approach to understand the fundamental principles of complex systems and the negative feedback mechanism, which is of great significance for researching system controlling and network resilience.
Computational analysis of patient-specific pulsatile blood flow: The influence of non-Newtonian models on wall shear stress assessment
Authors: Singh Damini , Singh Sarita
Published: January 2024

Blood is a sophisticated biological fluid with components like erythrocytes that give it non-Newtonian behavior. Hemodynamic factors such as velocity magnitude, pressure, and wall shear stress descriptors are the most important factors in the development of atherosclerosis. The wall shear stress descriptors are regulated not only by flow geometry but also by blood rheological properties. In the current study, we carried out a numerical analysis of the non-Newtonian pulsatile blood flow while taking into account a patient-specific geometry and transient boundary conditions. Non-Newtonian blood flow is modeled using the four non-Newtonian models: the power-law model, the Carreau model, the Casson model, and the Quemada model, and compared with the Newtonian model. Streamline analysis vividly illustrates velocity patterns, revealing the presence of recirculation zones near sinus regions. The study suggests the significance of selecting appropriate viscosity models for accurate assessments, particularly in regions with low time-average wall shear stress values, such as those associated with atherosclerotic plaques. The differences in the time-averaged wall shear stress between the four non-Newtonian models were found to be the highest in the Quemada model. The study concluded that the non-Newtonian model is required when the focus is on the low-time-averaged wall shear stress area.
VEnt: An air entrainment model for turbulent free surface flows
Authors: Yuan Ben , Li Jiajia , Carrica Pablo M. , Hendrickson Kelli , Yue Dick
Published: January 2024

We present a model for bubble entrainment caused by the interaction of turbulence with a free surface. The model improves over the mechanistic bubble entrainment model of Castro et al. [“A mechanistic model of bubble entrainment in turbulent free surface flows,” Int. J. Multiphase Flow 86, 35 (2016)] by replacing the original vortex/free surface interaction model with the model derived from direct numerical simulations introduced by Hendrickson et al. [“Modelling entrainment volume due to surface-parallel vortex interactions with an air–water interface,” J. Fluid. Mech. 938, A12 (2022)]. Implementation of the Hendrickson model for vortex/free surface interaction requires determining vortex number densities and velocities derived from simple models using a full turbulence spectrum that is dependent upon the local turbulent kinetic energy and dissipation. The resulting model has no adjustable constants and is applicable to high Reynolds number methodologies where the small-scale turbulence is not resolved but these scales can be characterized. We validate the model prediction of void fraction and bubble size distribution in the wake of a full-scale ship transom flow using both Reynolds Averaged Navier–Stokes (RANS) and hybrid RANS/Large Eddy Simulation approaches. We also present the model performance for the challenging problem of a full-scale ship executing a turning maneuver in irregular waves, indicating that the newly developed entrainment model is robust and performs satisfactorily for realistic full-scale problems.
Effect of wall stress models and subgrid-scale models for flow past a cylinder at Reynolds number 3900
Authors: Fan Guoqing , Liu Yuan , Zhao Weiwen , Wan Decheng
Published: January 2024

The wall-modeled large eddy simulation has achieved some success in simulating wall-bounded flows. However, their predictive accuracy in separated flow still requires further validation. In this study, we employ the open-source computational fluid dynamics toolbox OpenFOAM to numerically investigate the flow past a cylinder at subcritical Reynolds numbers ReD=3900. At two different sampling heights, h = 2nd and h = 4th, three wall stress models: the algebraic model, the equilibrium wall model (EQWM), and the non-EQWM (NEQWM), and five subgrid-scale (SGS) models: the Smagorinsky (SMAG) model, the k-equation SGS (KSGS) model, the wall-adapting local eddy viscosity (WALE) model, the dynamic SMAG (DSMAG) model, and the dynamic KSGS (DKSGS) model, are selected for comparative study. Various physical quantities, including statistical flow quantities, wall pressures, time-averaged wake velocity profiles, and Reynolds stresses, are extracted and compared with the experimental data. Power spectral analyses for wake velocity are conducted, and the three-dimensional vortex structures are illustrated. The results indicate that for small sampling height, all wall models yield favorable numerical simulation results. However, for larger sampling height, the NEQWM is preferred over the other two wall models. In terms of SGS models, the DKSGS model and WALE model perform better than other SGS models. The SMAG and KSGS models, due to inherent model limitations, struggle to accurately predict the flow separation angle and the Reynolds stresses in the free shear layer.
Cathodoluminescence investigation of defect states in n- and p-type AlN
Authors: Matthews Christopher M. , Ahmad Habib , Hussain Kamal , Chandrashekhar M. V. S. , Khan Asif , Doolittle W. Alan
Published: January 2024

State-of-the-art semiconducting aluminum nitride (AlN) films were characterized by cathodoluminescence (CL) spectroscopy in the range of 200–500 nm in an attempt to identify the energy levels within the bandgap and their associated defects. Near-band edge emission (around 206 nm) and high-intensity peaks centered in the near UV range (around 325 nm) are observed for both n- and p-type AlN films. The near UV peaks are potentially associated with oxygen contamination in the films. The p-type AlN films contain at least two unidentified peaks above 400 nm. Assuming that the dopant concentration is independent of compensation (i.e., in the perfect doping limit), three effective donor states are found from Fermi–Dirac statistics for Si-doped AlN, at ∼0.035, ∼0.05, and ∼0.11 eV. Similarly, a single effective acceptor energy of ∼0.03–0.05 eV (depending on the degeneracy factory considered) was found for Be doped AlN. CL investigation of doped AlN films supports claims that AlN may be a promising optoelectronic material, but also points to contaminant mitigation and defect theory as major areas for future study.
Calibration of the oscillation amplitude of quartz tuning fork-based force sensors with astigmatic displacement microscopy
Authors: Zhang Bi-Qin , Ma Fei-Cen , Xu Jia-Nan , Ren Dou-Dou , Zhou Dan , Pan Ting , Zhou Lei , Pu Qiaosheng , Zeng Zhi-Cong
Published: January 2024

Quartz tuning forks and qPlus-based force sensors offer an alternative approach to silicon cantilevers for investigating tip–sample interactions in scanning probe microscopy. The high-quality factor (Q) and stiffness of these sensors prevent the tip from jumping to the contact, even at sub-nanometer amplitude. The qPlus configuration enables simultaneous scanning tunneling microscopy and atomic force microscopy, achieving spatial resolution and spectroscopy at the subatomic level. However, to enable precise measurement of tip–sample interaction forces, confidence in these measurements is contingent upon the accurate calibration of the spring constant and oscillation amplitude of the sensor. Here, we have developed a method called astigmatic displacement microscopy with picometer sensitivity.
The effects of a smooth hump on the modal linear evolution of streamwise vortices over a yawed cone at Mach 6 from direct numerical simulations
Authors: Li Xiaohu , Zhang Bin , Chen Kuo , Yang Qiang , Chen Jianqiang , Tu Guohua
Published: January 2024

In this study, the influence of isolated three-dimensional (3D) humps on the linear evolution of streamwise vortex unstable modes over a yawed cone is investigated numerically. The yawed cone has a 7° half-angle at a 6° angle-of-attack, the freestream Mach number (Ma) is 6, and the unit Reynolds number is 1.0×107 m–1. The induced disturbance at the numerical inlet is obtained using the two-dimensional global stability theory (biglobal stability theory). The clear linear-evolution process and the growth rate curve of a single-frequency disturbance wave along the axial direction are obtained using well-designed direct numerical simulations. The numerical results show that the evolutionary paths of the inner and outer modes are related to the inward and outward vortices inside the mushroom structure of the leeward ray, respectively. However, a small part of the outer mode energy can also propagate downstream along the inward vortex. Moreover, the introduction of an inner mode at the inlet can not only excite the unstable inner mode but also trigger the unstable outer mode downstream after the amplitude of the inner mode is attenuated. At the same time, a clear mode transformation process among the outer modes is also observed inside the streamwise vortex-induced boundary layer. By comparing the results of the linear evolution of the disturbance over a smooth wall, it is found that the induced hump can enhance the inner mode instability, resulting in a hysteresis phenomenon of the outer mode amplification interval, which is in good agreement with the results of the spatial biglobal analysis in our previous work. Additionally, the induced hump can also delay the mode transformation process and does not induce new mode transformation mechanisms.
Measurement of jet gas–liquid interface fluctuations based on ultrasonic scattering
Authors: Liu Xiaokang , Yu Xiaoyu , Yu Xudong , Zhou Hao , Zhang Siyi , Li Jingxuan , Yang Lijun
Published: January 2024

Aero-engines and rocket engines regularly experience unstable combustion phenomena. In order to reveal the complex mechanism, it is necessary to measure the jet gas–liquid interface disturbances. However, most techniques require optical access and the measurement fails when the optical access is limited. Ultrasonic method can be considered as an alternative under this condition. The present work proposes an acoustic approach for measuring the jet gas–liquid interface based on ultrasonic scattering. A thorough investigation of the scattered acoustic field by the jet is conducted by experimental methods. The high-speed imaging technology is used to verify the ultrasonic measurement results. The direct measurement results demonstrate a relationship between the perturbation of the jet gas–liquid interface and that of ultrasonic scattered acoustic pressure in certain measuring direction. The scattered acoustic field is analyzed theoretically and practically by using customized metal scatters of certain size. Based on these findings, a database is created to enable the ultrasonic measurements to be calibrated. The corrected result shows that the correlation of ultrasonic measurements and results from cameras has been greatly improved, and the maximum relative error of the ultrasonic measurements is 30.9%, the average relative measurement error is 2.1%. It is proved that the method of determining the gas–liquid interface of jet by ultrasonic scattering wave is feasible. The method may also be used for the measurement of the overall jet fluctuations and breakup.
Squeeze flow of a Maxwell fluid between a sphere and a plate
Authors: Zheng Zhaolin , Chen Xuedong , Yang Wei
Published: January 2024

In this study, we investigate the squeeze flow behavior of an upper-convected Maxwell fluid between a sphere and a plate. Based on the Newtonian fluid velocity field, we use the perturbation method to derive analytical expressions for the pressure distribution and normal squeeze force of the sphere–plate squeeze flow, which can be implemented into the contact model for the discrete element simulation of a wet particle system with a Maxwell fluid. Additionally, the sphere–plate case investigated in this paper can be easily transformed into both the plate–plate and sphere–sphere cases, forming a set of complete contact force models with these two cases, thus offering a wider applicability.
Generation and distribution of turbulence-induced loads fluctuation of the horizontal axis tidal turbine blades
Authors: Wang Pengzhong , Li Kaifu , Wang Lu , Huang Bin
Published: January 2024

Horizontal axis tidal turbines (HATTs) working in a complex flow environment will encounter unsteady streamwise flow conditions that affect their power generation and structural loads, where power fluctuations determine the quality of electricity generation, directly affecting the grid and reliability of the power transmission system; fatigue loads affect various structures and mechanical components of the turbine, directly determining the lifespan and reliability of the turbine. To gain insight into the generation mechanism and distribution of these excitations, a large eddy simulation is employed to analyze the inflow turbulence and unsteady forces excitations by a three-blade HATT. A spectral synthesizer was used to generate incoming turbulence flow. The strip method was applied on the HATT by dividing the blade into 20 strips. The thrust received by each strip and the flow velocity upstream and downstream of the blade's root, middle, and tip were monitored. The distribution of unsteady loads on the blades was analyzed, as well as the relationship between flow velocity upstream and downstream of the blade and the unsteady characteristics of the blades. The simulation results show that the unsteady hydrodynamic fluctuations of the HATT blades reach up to 57.44% under a turbulent intensity of 10%. Through intuitive analysis of flow separation on the suction surface of the blade at various moments under a low tip speed ratio, we can comprehend the variations in inflow velocity and flow separation on the blade surface. Analyzing the distribution of blade load from root to tip reveals that the maximum load values are concentrated in the 14th–16th strips, corresponding to the region from 0.7R to 0.8R. Moreover, the middle and tip sections of the blades predominantly contribute to the harmonics of the 3BPF (blade passing frequency) and broadband, with the middle section making a greater contribution. The tip section primarily contributes to harmonics above 3BPF. This research want to makes a valuable contribution to the comprehensive understanding of turbulence-induced exciting forces and the practical engineering design of HATT.
Geometrical decomposition of nonadiabatic interactions to collective coordinates in many-dimensional and many-state mixed fast–slow dynamics
Authors: Takatsuka Kazuo
Published: January 2024

In general, for many-dimensional and many-state nonadiabatic dynamics composed of slow and fast modes, we geometrically decompose the nonadiabatic interactions by means of the method of singular value decomposition. Each pair of the left and right singular vectors connecting the slow (nuclear) and fast (electronic) modes gives rise to a one-dimensional collective coordinate, and the sum of them amounts to the total nonadiabatic interaction. The analysis identifies how efficiently the slow modes, thus decomposed, can induce a transition in their fast counterparts. We discuss the notions of nonadiabatic resonance and nonadiabatic chaos in terms of the decomposition.
Numerical study on the flow around an elliptic cylinder with different aspect ratios in the subcritical regime using large eddy simulation
Authors: Li Yuxin , Li Bo , Li Tian , Zhang Yuanzhao
Published: January 2024

The aerodynamic characteristics, flow fields, and flow patterns of the flow around an elliptic cylinder are investigated in this paper using large eddy simulation (LES). The Reynolds number (Re) is fixed at 16 000 in the subcritical regime, and the aspect ratio (AR) of the elliptic cylinder is varied from 0.6 to 1.4 with an increment of 0.2. The numerical model applied is initially validated for the case of AR = 1, showing good agreement with previous studies. The numerical results indicate that both the mean drag coefficient and the root mean square of lift coefficient of the elliptic cylinder decrease with increasing AR. The total drag is decomposed into two components: it indicates that the pressure drag is dominant. The primary separation point of the elliptic cylinder shifts backward with increasing AR within the range of 86.4°–92.3°. The flow fields are analyzed in detail through the time-averaged velocity profiles along three different axes. Additionally, the two-dimensional (2D) and three-dimensional (3D) visualizations of the wake patterns are also provided to show the different vortex shedding mode and the characteristics of vortex structure for different ARs. This study supplements the basic aerodynamic parameters and details of the flow around an elliptic cylinder and discusses the influence of AR at a moderate Re in the subcritical regime and has a certain significance for further optimization of the simplified model of the human body for efficient aerodynamic testing of sport garments.
Structure evolution and energy band modulation in Ba-doped BiFeO3 thin films
Authors: Liang Ning , Wang Can , Yao Xiaokang , Wang Xinyan , Yan Tao , Wang Rui , Jin Qiao , Guo Xiang , Guo Erjia , Ge Chen , He Meng , Yang Guozhen , Jin Kuijuan
Published: January 2024

Bi1−xBaxFeO3 (BBFO, x = 0, 0.03, 0.1) thin films were epitaxially grown on SrRuO3-buffered SrTiO3 (001) substrates by pulsed laser deposition. With increasing Ba content, the BBFO thin films show significantly reduced leakage currents but suppressed ferroelectric polarization. X-ray diffraction reciprocal space mappings and Raman spectra indicate a structural evolution from a rhombohedral-like to tetragonal-like phase in the BBFO thin films. Optical absorption and photoelectron spectroscopy measurements demonstrate a modulation of energy band structures in the BBFO thin films. With A-site Ba acceptor doping, the BBFO thin films exhibit a blue-shift of optical bandgap and an increase in work function. The energy positions of conduction and valence bands of the BBFO thin films have been modulated, and the Fermi level shifts down to the center of the forbidden band, but acceptor-doped BFO thin films still show n-type conduction. The presence of extra oxygen vacancies by acceptor doping is supposed to make contribution to conduction behavior. This study provides a method to manipulate the functional properties and gives insights into the physics of Ba doping in BFO thin films.
Numerical study of the coherent characteristics of the blade tip of a micro centrifugal compressor and its application in a new unsteady casing-treatment experiment
Authors: Zhang Hongxin , Yang Yuxuan , Xu Chi , Hong Shuli , Huang Guoping
Published: January 2024

The tip-leakage vortex, as the dominant coherent structure of the blade tip of a compressor, is an important source of losses in centrifugal compressor rotors; it limits the stall margin and can even cause compressor surge. The miniaturization of mechanical components has attracted significant attention; however, the miniaturization of compressors—particularly centrifugal compressors—further increases the adverse effects of the tip-leakage vortex. This study sought to establish a new passive unsteady flow-control method for a micro centrifugal compressor using equal-circumferential-spacing through-holes on its casing. This approach fully exploits the unsteady characteristics of the flow field. A numerical study of the coherent characteristics of the blade tip was carried out using dynamic mode decomposition. The numerical conclusions were then applied to a physical system. The results of experimental tests of this system indicate that the improved flow-control method can increase the maximum efficiency and stall margin of the compressor by 2.5% and 9.0%, respectively, and it can also increase the maximum pressure ratio.
Early warning and monitoring of the safety risk of coastal nuclear power plant cold source under the stress from Phaeocystis globosa blooms
Authors: Ni Jialin , Chen Hongyi , Dai Li , Ji Jianda , Lin Jing , Yu Tao
Published: January 2024

Context In recent years, Phaeocystis globosa has become a typical red tide species in the Beibu Gulf, posing a safety hazard to the cold-water intake system of the Guangxi Fangchenggang Nuclear Power Plant. Aims To establish an effective early risk-warning monitoring and ensure the safety of nuclear power plant cold-water intakes. Methods In this study, a multifactor and multilevel early risk-warning monitoring system was established using the early warning idea of ‘risk grading’. Key results The results showed that this method can analyse the influence trend of marine-environment changes on the growth of P. globosa and improve the timeliness of early warning and forecasting. Conclusions The method established in this paper can effectively guide coastal nuclear power enterprises to conduct early risk warning and monitoring of P. globosa and improve the accuracy of early warning and forecasting. Implications The methed is of great significance to coastal nuclear power enterprises dealing with red tide disasters caused by P. globosa blooms.
Helical sulfonyl-γ-AApeptides modulating Aβ oligomerization and cytotoxicity by recognizing Aβ helix
Authors: Liu Heng , Cui Yunpeng , Zhao Xue , Wei Lulu , Wang Xudong , Shen Ning , Odom Timothy , Li Xuming , Lawless William , Karunarathne Kanchana , Muschol Martin , Guida Wayne , Cao Chuanhai , Ye Libin , Cai Jianfeng
Published: January 2024

In contrast to prevalent strategies which make use of β-sheet mimetics to block Aβ fibrillar growth, in this study, we designed a series of sulfonyl-γ-AApeptide helices that targeted the crucial α-helix domain of Aβ13-26 and stabilized Aβ conformation to avoid forming the neurotoxic Aβ oligomeric β-sheets. Biophysical assays such as amyloid kinetics and TEM demonstrated that the Aβ oligomerization and fibrillation could be greatly prevented and even reversed in the presence of sulfonyl-γ-AApeptides in a sequence-specific and dose-dependent manner. The studies based on circular dichroism, Two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) spectra unambiguously suggested that the sulfonyl-γ-AApeptide Ab-6 could bind to the central region of Aβ
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and induce α-helix conformation in Aβ. Additionally, Electrospray ionisation-ion mobility spectrometry–mass spectrometry (ESI-IMS-MS) was employed to rule out a colloidal mechanism of inhibitor and clearly supported the capability of Ab-6 for inhibiting the formation of Aβ aggregated forms. Furthermore, Ab-6 could rescue neuroblastoma cells by eradicating Aβ-mediated cytotoxicity even in the presence of pre-formed Aβ aggregates. The confocal microscopy demonstrated that Ab-6 could still specifically bind Aβ
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and colocalize into mitochondria in the cellular environment, suggesting the rescue of cell viability might be due to the protection of mitochondrial function otherwise impaired by Aβ
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aggregation. Taken together, our studies indicated that sulfonyl-γ-AApeptides as helical peptidomimetics could direct Aβ into the off-pathway helical secondary structure, thereby preventing the formation of Aβ oligomerization, fibrillation and rescuing Aβ induced cell cytotoxicity.
Effects of climate, land use, and human population change on human–elephant conflict risk in Africa and Asia
Authors: Guarnieri Mia , Kumaishi Grace , Brock Cameryn , Chatterjee Mayukh , Fabiano Ezequiel , Katrak-Adefowora Roshni , Larsen Ashley , Lockmann Taylor M. , Roehrdanz Patrick R.
Published: January 2024

Human–wildlife conflict is an important factor in the modern biodiversity crisis and has negative effects on both humans and wildlife (such as property destruction, injury, or death) that can impede conservation efforts for threatened species. Effectively addressing conflict requires an understanding of where it is likely to occur, particularly as climate change shifts wildlife ranges and human activities globally. Here, we examine how projected shifts in cropland density, human population density, and climatic suitability—three key drivers of human–elephant conflict—will shift conflict pressures for endangered Asian and African elephants to inform conflict management in a changing climate. We find that conflict risk (cropland density and/or human population density moving into the 90th percentile based on current-day values) increases in 2050, with a larger increase under the high-emissions “regional rivalry” SSP3 - RCP 7.0 scenario than the low-emissions “sustainability” SSP1 - RCP 2.6 scenario. We also find a net decrease in climatic suitability for both species along their extended range boundaries, with decreasing suitability most often overlapping increasing conflict risk when both suitability and conflict risk are changing. Our findings suggest that as climate changes, the risk of conflict with Asian and African elephants may shift and increase and managers should proactively mitigate that conflict to preserve these charismatic animals.