Physical Approach Research Articles

Topology optimization for 3D fluid diode design considering wall-connected structures

This paper proposes a density-based topology optimization method for the three-dimensional design of fluid diodes considering wall-connected structures based on the fictitious physical modeling approach. The optimum design problem of fluid diodes is formulated as maximizing the energy dissipation in the reverse flow subject to the upper bound constraint of the energy dissipation in the forward flow. A fictitious physical model and a geometric constraint are constructed to detect and restrict the “floating” solid domains, which are not connected to the outer boundaries. The sensitivities of cost functions are derived and computed based on the continuous adjoint method. The finite volume method is employed to discretize the governing and adjoint equations to mitigate the huge computational costs of three-dimensional fluid analysis. Numerical investigations are presented to validate the fictitious physical model and the geometric constraint for excluding “floating” islands. Finally, topology optimization for fluid diodes with and without the geometric constraint is performed, and the result demonstrates that the proposed method is capable of generating fluid diodes with wall connectivity, while maintaining a good functional performance.

A Physical Approach to Lagrangian Equations with Bundle Structure for Minkowski 3-Space

Minkowski 3-space is important because it is the spatial structure in which physical events occur. Therefore, in this study, we examined the time-dependent Lagrangian energy equations in Minkowski 3-space. To facilitate the examination of the necessary mechanical structure and solutions with respect to time, we employed the jet bundle structure. This approach has made the creation of the necessary geometric structures more comprehensible in terms of coordinate basis. To interpret the obtained Lagrangian energy equations and to understand the significance of the time parameter, an example is also provided in our study.

Green synthesis of metal oxide nanoparticles using plant extract, its structural and optical properties and application

The nanoparticles being the most utilized invention of nanoscience and technology, which is used in many aspects of science and medicine. These remarkable utilization of particles is due to their diverse properties at nano level. The chemical and physical approach to formation of nanoparticles are toxic to surroundings also leading to less efficient usage of them in medical perspective. In this article green synthesis of cobalt ferrite nanoparticles is done by sol-gel auto combustion using Caralluma Tuberculata extract as reducing agent, iron nitrate and cobalt nitrate as precursor salts. Cobalt ferrite nanoparticles are used in many aspects for certain properties such as antimicrobial activities the synthesized particles were characterized using different techniques such as UV Spectroscopy, SEM, FTIR, XRD,EDX. The antibacterial activity of cobalt ferrite nanoparticles is performed which shows remarkable results by increasing the inhibition zone for both E coli and Staphylococcus bacteria

Sensitivity Analysis of Sentinel-2 Imagery to Assess Urban Tree Functional Traits: A Physical Approach Based on Local Climate Zones

Urban trees contribute to urban well-being but face challenging environments that can reduce their lifespan and increase young tree mortality. Although many studies have used remote sensing data to monitor the functional status of trees in rural areas, few have done so in urban areas to assess the health or estimate the biomass of large green areas. This study assessed the suitability of using Sentinel-2 images to characterize two urban tree functional traits—leaf chlorophyll content (Cab) and leaf area density (LAD)—in isolated trees and tree rows. Simulated Sentinel-2 images were generated using the DART radiative transfer model, considering 16 tree-endogenous and 14 tree-exogenous parameters, with 15 vegetation indices (VIs) analyzed. Sensitivity analysis was performed in four contrasting urban environments using local climate zone taxonomy. The accuracy of the simulated images was validated with real Sentinel-2 images, field measurements, and ancillary data collected for four tree species in Rennes, France. The results showed that the tree parameters significantly influenced Sentinel-2 spectral bands, with NGBDI and OSAVI VIs being most sensitive to Cab and LAD. The model showed high accuracy, with a mean RMSE of 0.016 for key spectral bands. The results also highlighted the importance of considering ancillary data to capture specific urban characteristics.

The Impact of Total Physical Response Approach in Vocabulary Acquisition and Motivation among Rural Chinese Students

The Impact of Total Physical Response Approach in Vocabulary Acquisition and Motivation among Rural Chinese Students

Effect of cardiovascular fitness on performance metrics in Bangladeshi women cricket: a role-specific analysis employing the harvard step test

Background: Cardiovascular fitness is essential for sports performance, enabling players to endure intense training, delay fatigue, and reduce injury risk—all critical factors for achieving optimal results in competitive sports like cricket. Emphasizing inclusive health ensures that all athletes enhance their cardiovascular fitness and overall performance. Purpose: This study aimed to investigate the impact of cardiovascular fitness, assessed using the Harvard Step Test, on the performance indicators of Bangladeshi women cricketers across their respective playing roles. Method: 104 players, including 34 batters, 38 bowlers, and 32 all-rounders, were voluntarily selected from the “Bangladesh National Women’s Cricket League 2021-22”. Cardiovascular fitness was evaluated through the Harvard Step Test, and role-specific performance metrics such as strike rate, bowling economy, and dismissal rates were analyzed. Statistical analyses included descriptive statistics and one-way ANOVA to assess differences in aerobic fitness across player roles and correlation analyses to examine the relationships between performance metrics and Harvard Step Test scores. Results: The multi-group comparison did not reveal a statistically significant difference in aerobic fitness across the playing roles, F(2, 101) = 0.668, p = 0.515. Additionally, the Harvard Step Test scores showed a weak and statistically non-significant relationship with role-specific performance metrics: strike rate (r = 0.20, p = 0.06) for batters, bowling economy (r = -0.09, p = 0.51) for bowlers, and dismissals (r = 0.10, p = 0.38) for fielders. Conclusion: Cardiovascular efficiency is similar across batters, bowlers, and all-rounders among Bangladeshi women cricketers. The Harvard Step Test score is not directly associated with role-specific performance in women's cricket. These findings suggest that training programs should adopt a holistic physical fitness approach, incorporating role-specific training to enhance the overall abilities of female cricketers and contribute to the development of women's cricket in Bangladesh.

ТРАНСФОРМАЦІЯ СТРУКТУРИ І ЗМІСТУ КУРСУ ГЕОГРАФІЇ ВОСЬМОГО КЛАСУ ДЛЯ ЗАКЛАДІВ ЗАГАЛЬНОЇ СЕРЕДНЬОЇ ОСВІТИ

The article is focused on the analysis of the structure and content of Geography study in the 8th grades of general secondary educational institutions based on the model curriculum, developed by the team under the supervision of S. P. Zapototskyi. According to it, the content block related to the study of the population was removed from the 8th and instead transferred to the 9th grade course. Thus, the content of the course “Geography” in the 8th grade will encompass the following 4 chapters: Chapter I “Cartographic image of Ukraine”, Chapter II “Nature of Ukraine”, Chapter III “Natural Resource Management” and Chapter IV “Space – Territory – State”. Instead of the topic “Ukrainian and World Population” in the 8th grade, the inclusion of which in this course at one time was an unsuccessful experiment, two Chapters were introduced under the names “Natural Resource Management” and “Space – Territory – State”. Chapter “Natural Resource Management” logically completes the study of the nature of our state from the standpoint of the resource approach and perspectives of nature use, and “Space – Territory – State” is a kind of a transitional link to the study of Ukrainian and world social geography in the 9th grade. However, a more detailed analysis of the content of the topics included in the geography course covered in the 8th grade according to the model program offered by S. P. Zapototskyi and others, prompts to draw attention to some debatable issues and to offer author’s vision of improving the content of the educational discipline. The main suggestions concern the preservation of a typical physical and geographical approach to the study of the nature of Ukraine in Chapter II, In topic 1. of section IV. "Ukrainian state" a very important aspect of consideration is the affirmation of the idea that Ukraine is the inheritor of the state tradition of the Slavic tribe of the Ants. Another strength of the program is the project activity to establish the features of the formation of capable territorial communities formed after the decentralization reform. The main narrative to be relayed by topic 2 "Ukraine's place on the political map of the world" is that Ukraine is a sovereign European state, a candidate country for EU membership, which has to defend its independence from Russian aggression in a fair armed struggle. and some clarification of the content in Chapter III “Natural Resource Management”.

Physical therapy approach and non-invasive modalities in treatment of vaginal laxity: a literature review.

Pelvic floor physical therapy (PFPT) and noninvasive modalities can be more safe and available treatments for vaginal laxity (VL) with less risk of postsurgical complications. The purpose of this review is to define the concepts of PFPT and noninvasive modalities, examine the evidence supporting those modalities as a treatment for VL, and evaluate their effectiveness. Between 2002 and 2023, clinical studies including women diagnosed with VL were examined in the Web of Science, Cochrane Library, Scopus, and PubMed databases. Exclusion criteria included studies with no outcomes or inadequate data, procedures, suggestions, editorials, book chapters, letters to editors, reviews, meta-analyses, animal research, and articles in languages other than English. Only seventeen studies have been identified. Four studies have demonstrated the impact of PFPT (low- and medium-energy radiofrequency (RF), ultrasound, low-energy laser treatment, par sacral stimulation, the knack method, and pelvic floor exercises), and thirteen studies have discussed the impact of noninvasive modalities (RF, combined multipolar RF with pulsed electromagnetic, combined RF and pulsed electromagnetic field, high-intensity focused ultrasound, CO2 laser, combining multipolar RF and hybrid fractional laser, microfocused ultrasound, and the VIVEVE surface-cooled RF) on vaginal laxity. This review indicates many knowledge areas that must be attempted in order to understand the influence of nonstrengthening physical therapy and noninvasive methods on vaginal laxity. In addition to the mechanisms behind their impacts. In addition, we strongly recommend that more clinical trials of high methodological and interventional quality are required to investigate the efficacy of various physical therapy approaches, including electrical stimulation, biofeedback exertion, acupressure, manual therapy, neuromodulation, core exercise therapy, hydrotherapy, well-designed ultrasound therapy protocols, and vaginal weight training.

A hybrid physical modeling and AUKF approach for optimizing low-temperature charging of lithium-ion batteries

A common method for charging lithium-ion batteries at low temperatures involves preheating to mitigate low charging efficiency and safety risks from lithium dendrite growth. However, preheating alone is insufficient for rapid and safe charging. Optimization of low temperature charging requires consideration of the coupling relationship between heating and charging processes, while avoid lithium plating. Therefore, this study first constructs an electrochemical-thermal coupled model suitable for a broad temperature range to access the internal states of battery during low-temperature charging, ensuring lithium plating-free. Then, a hybrid physical modeling and AUKF method is proposed to accurately capture the changing state of charge (SOC) and state of temperature (SOT) during low-temperature charging, which is essential to improve the simulation accuracy of the model. After that, this study proposes a multi-stage heating-charging strategy which is controlled by hybrid physical modeling and AUKF approach to consider charging efficiency and safety. Optimization algorithm is used to obtain the optimal sequence of decisions for charging and heating under different phases to achieve the highest charging efficiency. Compared to One-stage heating-charging strategy, the proposed method offers superior charging efficiency, providing certain convenience for the operation of lithium-ion batteries in low temperature environment.

Modeling of natural first stroke stepped leader characteristics

The paper constitutes a novel physical approach to the different stages of negative leader stepping in cloud-to-ground lightning, starting with determination of the length of the negative streamer zone below the leader tip. The positive space leader, belonging to a pre-existing space leader, propagates towards the main leader tip, bridging the streamer zone. Such propagation time however is too short for leader thermalization. The thermalization, with associated substantial drop in the internal voltage gradient, occurs over a much longer time, through corona current injected at the tip of the moving negative space leader. The latter stage constitutes the determining factor for the time interval between steps. The model has then been applied to leaders with prospective return stroke current of 3–228 kA, leader tip height of 23–2000 m, leader charge linearly decaying to practically vanish at heights of either 2500 m or 4500 m. For the conditions investigated, the step length varies in the range 3.5 m to 39 m, the bridging time of the streamer zone by positive space leader in the range 0.8 - 3 μs, time interval between steps in the range 8.5–92 μs, yielding mean stepped leader speed in the range 1.0 - 11.6 × 105 m/s. Whenever possible the model predictions were satisfactorily compared to field measurements. Interaction between the negative downward leader and an upward connecting leader during the attachment process is out of scope of this work.

Graphdiyne‐Based Nickel–Cobalt Bimetallic Sulfide Cocatalyst for Efficient Photocatalytic Hydrogen Evolution

Initially, CoNiSx is synthesized on the graphdiyne (GDY) surface through a precipitation method, followed by the straightforward physical stirring approach to attach CoNiSx/GDY to the maple leaf CdS. This synthesis method significantly mitigates the accumulation of CoNiSx/GDY and concurrently augments the count of sites that are active for generating hydrogen. This three‐phase composite demonstrates exceptional performance in the area of photocatalytic hydrogen production, achieving a hydrogen evolution rate of 15.37 mmol·h−1 g−1. The employment of various characterization methodologies and density functional theory calculations have demonstrated the formation of a Z‐scheme heterojunction forms between GDY and CdS. This discovery indicates that the combination of GDY and CdS markedly improves the photogenerated carrier separation capability of the composite catalyst. The cocatalyst CoNiSx loaded on GDY effectively accelerates the electron transfer from the conduction band of GDY, thereby reducing the photogenerated carrier complexation of GDY. This phenomenon results in an increased quantity of photogenerated electron holes engaged in the redox reaction, ultimately achieving exceptional photocatalytic performance.

A hovering bubble with a spontaneous horizontal oscillation

Active matters, characterized by multi-mode motions, have been emerging for both engineering and biological applications. Generally, active objects rely on the symmetry-broken structures, compositions, or interfacial activities through a physical or chemical approach. Here, we report an active bubble spontaneously hovering with a horizontal oscillation at the solid/liquid interface by impacting a stationary laser beam into a liquid through a transparent solid cover. This spontaneous oscillation mode of the bubble synchronizes with that of the interfacial temperature and hydrodynamical flow. A physical mechanism is proposed, and the scaling analysis of the oscillation frequency agrees well with experiments in various liquids under different laser powers. Additionally, the bubble trajectory rotates azimuthally, arising from the symmetry breaking of the vortex pair accompanying the oscillation. Moreover, the double pendulum of oscillation bubbles has been demonstrated, achieving a preferable oscillation direction in a controllable way. These findings would not only advance our understanding of active matters but also shed light on the bubble-mediated technological applications, such as microrobots and drug deliveries.

Impact of high-speed nanodroplets on various pathogenic bacterial cell walls.

Although existing disinfection techniques demonstrate bactericidal effects through chemical reactions, concerns regarding human toxicity and environmental contamination have been raised. To the best of our knowledge, this study is the first in the world to reveal that the use of this technology, with nanodroplets of less than 100 nm, can destroy and sterilize bacterial cells by colliding with biofilm-forming bacteria at 75 MPa. Furthermore, because this technology uses only water, it can solve the problems of human toxicity and environmental contamination caused by existing disinfection techniques. Because of its minimal water usage, it can be employed for sanitation worldwide without being limited to specific regions. Our report proposes an unprecedented physical disinfection approach that utilizes a high-speed nanodroplet generation technology.

Changes in diffusion MRI and clinical motor function after physical/occupational therapies in toddler-aged children with spastic unilateral cerebral palsy.

Diffusion-weighted magnetic resonance imaging (DMRI) is a potential tool to assess changes in brain connectivity and microstructure resulting from physical and occupational therapy in young children with cerebral palsy. This works was carried out to assess whether DMRI can detect changes after 36 weeks of physical and occupational therapy in the microstructure and connectivity of the brains of children with cerebral palsy and determine whether imaging findings correlate with changes in clinical measures of motor function. Five children underwent anatomical MRI and DMRI and evaluations of motor function skills at baseline and after 36 weeks of intensive or once-weekly physical and occupational Perception-Action Approach therapies. Diffusion tensor imaging and constrained spherical deconvolution methods were used to calculate fractional anisotropy (FA) and fiber orientation distribution functions (fODFs), respectively. The fODFs were used to generate tractograms of the cerebrospinal tract (CST). After 36 weeks of physical and occupational therapy, all children showed increases in motor function. No changes were observed in anatomical MRI before and after therapy but CST tractography did show small differences indicating possible altered microstructure and connectivity in the brain. FA values along the CSTs, however, showed no significant changes. Reliable longitudinal DMRI can be employed in toddler-aged children with CP and DMRI has the potential to monitor neuroplastic changes in white matter microstructure. However, there is a high variability between subjects and clinical improvements were not always correlated with measures of FA along the CST.

Women police leaders: attitudes about policing and experiences in the occupation

PurposeThis study explored women police leaders’ (n = 503) attitudes and experiences relative to men police leaders (n = 3,359) and women police officers (n = 1,153) with no supervisory responsibilities.Design/methodology/approachSelf-reported survey data were collected from 5,015 officers in 85 United States law enforcement agencies.FindingsCompared with men police leaders, women police leaders were more likely to identify inequalities in the workplace, empower community members’ voices in defining legitimate forms of policing, elevate the importance of police misconduct and reject a tough physical approach. Women police leaders were also more likely than male police leaders to think that effective leadership influences the behavior of subordinates and more likely to feel that the rules leave room for interpretation. Black women police leaders reported different attitudes and experiences than White women police leaders, including recognizing greater inequalities, prioritizing increased law enforcement activities and experiencing less occupational burnout. Except for the seriousness of misconduct, there were no differences between women police leaders and women police officers without supervisory responsibilities.Originality/valueThis study contributes to the ongoing conversation about women in policing and how increasing the number of women in leadership roles affects law enforcement agencies and the public’s experiences with policing. As policing continues to face calls for reform and employment challenges, increasing the number of women in leadership plays a vital role in producing law enforcement agencies that are equitable and efficacious.

Utilizing porous dielectric material to enhance the performance of capacitive MEMS accelerometers for shaft monitoring

This research investigates the optimization of the performance of a capacitive-based microelectromechanical systems (MEMS) shaft monitoring accelerometer using a porous soft dielectric material with high polarization capability and low Young’s modulus. The nonlinear governing equations of a microbeam with a proof mass coupled with the squeeze motion equation of the polymeric dielectric material excited by shaft vibrations are extracted and solved in both the spatial and temporal domains. The studied model considers the stiffness, dissipative, and inertial effects of the polymeric material and incorporates porosity as a displacement-dependent variable, which introduces an additional nonlinearity. After discretizing the coupled nonlinear differential equations using the Galerkin method, the response in the frequency domain is obtained by applying an energy balance method, where the coefficients of the Fourier expansion of the response are found by arc-length continuation through a physical gradient descent learning-based approach method. The occurrence of secondary and primary resonances in different harmonic responses is studied for different harmonic acceleration inputs. The equivalent rigidity of the design is investigated for different shaft frequency magnitudes and different proof mass geometries. The effect of the initial porosity volume fraction of the elastomeric dielectric material on the dynamic response of the accelerometer is also examined. The sensor’s sensitivity is dependent on its geometry and properties and can vary based on the structure’s material parameters. Consequently, the selection of different geometries and materials may result in either an improvement or a deterioration of the sensor’s performance.

Study and modeling of the ultrasonic ambient noise induced by the fluid-structure interaction in a pipe

An elastic guided wave-based structural health monitoring (SHM) system consists in examining the integrity of a structure through the propagation of elastic waves. In this context, passive methods turn initial hindrances into advantages by making use of the ambient ultrasonic noise in a structure in operation, through the cross-correlation. Although they have been empirically applied in several configurations, no model is available to predict the link between the flow regime and the convergence of the ambient noise correlation towards the impulse response of the system. Considering the different parameters involved in the case of a pipe, a physical approach of this issue may be studied through the turbulent boundary layer, which has long been described by the Corcos model. Corcos-like models have essentially been applied so far on the audible range, below 1 kHz, where we are interested in frequencies around 100 kHz, typical for SHM applications. The semi-empirical model allows to determine a wall boundary pressure, which, applied at the pipe's inner boundaries, acts as a source term for ultrasonic elastic waves propagating in the pipe. Our goal is then to study if such a model can be used at these high frequencies to reproduce the experimental observations.

Mapping Microplastic Movement: A Phase Diagram to Predict Nonbuoyant Microplastic Modes of Transport at the Particle Scale.

Microplastics pose numerous threats to aquatic environments, yet understanding their transport mechanisms remains limited. Drawing from natural sediment research provides valuable insights to address this knowledge gap. One key dimensionless number used to describe sediment transport is the transport stage, referring to the ratio between the flow shear velocity and the particle settling velocity. However, variations in physical properties, such as shape and density, raise concerns about the applicability of existing sediment transport theories to microplastics. To address this challenge, we employed a physical modeling approach, examining 24 different nonbuoyant microplastic particles in a turbulent open channel flow. Utilizing 3D particle tracking, a total of 720 trajectories were recorded and analyzed. Microplastic particles exhibited transport modes akin to natural sediments, including rolling/sliding, saltation, and suspension. The transport stage strongly correlated with these modes, as well as with the mean forward velocity and mean position in the water column. Notably, particle shape emerged as a critical factor influencing transport dynamics. Due to their lower settling velocity, fibers tended to stay closer to the water surface with lower forward velocities compared to spheres. Based on the laboratory results, a new phase diagram for microplastics is introduced analogous to an existing diagram for sediments.

Deterministic Synthesis of a Two-Dimensional MAPbI3 Nanosheet and Twisted Structure with Moiré Superlattice.

The synthesis of extremely thin 2D halide perovskites and the exploration of their interlayer interactions have garnered significant attention in current research. A recent advancement we have made involves the development of a successful technique for generating ultrathin MAPbI3 nanosheets with controlled thickness and an exposed intrinsic surface. This innovative method relies on utilizing the Ruddlesden-Popper (RP) phase perovskite (BA2MAn-1PbnI3n+1) as a template. However, the precise reaction mechanism remains incompletely understood. In this work, we systematically examined the dynamic evolution of the phase conversion process, with a specific focus on the influence of inorganic slab (composed of [PbI6]4- octahedrons) numbers on regulating the thickness and quality of the resulting MAPbI3 nanosheets. Additionally, the atomic structure is directly visualized using the transmission electron microscopy (TEM) method, confirming its exceptional quality. To illustrate interfacial interactions in ultrathin structures, artificial moiré superlattices are constructed through a physical transfer approach, revealing multiple localized high-symmetry stacks within a distinctive square moiré pattern. These findings establish a novel framework for investigating the physics of interfacial interactions in ionic semiconducting crystals.

Progress of research in the application of ultrasound technology for the treatment of Alzheimer's disease.

Alzheimer's disease is a common neurodegenerative disorder defined by decreased reasoning abilities, memory loss, and cognitive deterioration. The presence of the blood-brain barrier presents a major obstacle to the development of effective drug therapies for Alzheimer's disease. The use of ultrasound as a novel physical modulation approach has garnered widespread attention in recent years. As a safe and feasible therapeutic and drug-delivery method, ultrasound has shown promise in improving cognitive deficits. This article provides a summary of the application of ultrasound technology for treating Alzheimer's disease over the past 5 years, including standalone ultrasound treatment, ultrasound combined with microbubbles or drug therapy, and magnetic resonance imaging-guided focused ultrasound therapy. Emphasis is placed on the benefits of introducing these treatment methods and their potential mechanisms. We found that several ultrasound methods can open the blood-brain barrier and effectively alleviate amyloid-β plaque deposition. We believe that ultrasound is an effective therapy for Alzheimer's disease, and this review provides a theoretical basis for future ultrasound treatment methods.