bluuebunny/crossref_metadata_2025 huggingface dataset:
Do the associations of daily steps with mortality and incident cardiovascular disease differ by sedentary time levels? A device-based cohort study
Authors: Ahmadi Matthew N , Rezende Leandro F M , Ferrari Gerson , Del Pozo Cruz Borja , Lee I-Min , Stamatakis Emmanuel
Published: March 2024

Objectives

This study aims to examine the associations of daily step count with all-cause mortality and incident cardiovascular disease (CVD) by sedentary time levels and to determine if the minimal and optimal number of daily steps is modified by high sedentary time.

Methods

Using data from the UK Biobank, this was a prospective dose–response analysis of total daily steps across low (<10.5 hours/day) and high (≥10.5 hours/day) sedentary time (as defined by the inflection point of the adjusted absolute risk of sedentary time with the two outcomes). Mortality and incident CVD was ascertained through 31 October 2021.

Results

Among 72 174 participants (age=61.1±7.8 years), 1633 deaths and 6190 CVD events occurred over 6.9 (±0.8) years of follow-up. Compared with the referent 2200 steps/day (5th percentile), the optimal dose (nadir of the curve) for all-cause mortality ranged between 9000 and 10 500 steps/day for high (HR (95% CI)=0.61 (0.51 to 0.73)) and low (0.69 (0.52 to 0.92)) sedentary time. For incident CVD, there was a subtle gradient of association by sedentary time level with the lowest risk observed at approximately 9700 steps/day for high (0.79 (0.72 to 0.86)) and low (0.71 (0.61 to 0.83)) sedentary time. The minimal dose (steps/day associated with 50% of the optimal dose) of daily steps was between 4000 and 4500 steps/day across sedentary time groups for all-cause mortality and incident CVD.

Conclusions

Any amount of daily steps above the referent 2200 steps/day was associated with lower mortality and incident CVD risk, for low and high sedentary time. Accruing 9000–10 500 steps/day was associated with the lowest mortality risk independent of sedentary time. For a roughly equivalent number of steps/day, the risk of incident CVD was lower for low sedentary time compared with high sedentary time.
Efficacy of migraine prophylaxis treatments for treatment-naïve patients and those with prior treatment failure: a protocol for systematic review and network meta-analysis of randomised controlled trials
Authors: Numthavaj Pawin , Anothaisintawee Thunyarat , Attia John , McKay Gareth , Thakkinstian Ammarin
Published: March 2024

Introduction

Migraine headache is a significant health problem affecting patients’ psychological well-being and quality of life. Several network meta-analyses (NMAs) have compared the efficacy of migraine prophylaxis medications. However, some have focused exclusively on oral medications, while others were limited to injectable medications. Moreover, none of these NMAs conducted a stratified analysis between treatment-naïve patients and those with prior treatment failure. Therefore, this systematic review and NMA will compare the efficacy among all treatments for migraine prophylaxis, stratified by the treatment status of patients (ie, treatment-naïve and previous treatment failure).

Methods and analysis

Randomised-controlled trials that included patients with chronic or episodic migraine, assessed the efficacy of oral or injectable treatments for migraine prophylaxis and measured the outcomes as monthly migraine day, monthly headache day, migraine-related disability, health-related quality of life or adverse drug events will be eligible for inclusion in this review. Relevant studies will be searched from Medline, Scopus, the US National Institutes of Health Register, and the World Health Organization International Clinical Trials Registry Platform (WHO-ICTRP) databases since inception through 15 August 2023. Risk of bias assessment will be performed using a revised tool for assessing the risk of bias in randomised trials. Two-stage NMA will be applied to compare relative treatment effects among all treatments of migraine prophylaxis. Surface under the cumulative ranking curve will be applied to estimate and rank the probability to be the best treatment. Consistency assumption will be assessed using a design-by-treatment interaction model. Publication bias will be assessed by comparison-adjusted funnel plot. All analyses will be stratified according to patients’ status (ie, treatment-naïve and prior treatment failure).

Ethics and dissemination

This study is a systematic review protocol collecting data from published literature and does not require approval from an institutional review board. Results from this systematic review will be published in a peer-reviewed journal.

PROSPERO registration number

CRD42020171843.
Modifiable prognostic factors of high societal costs among people on sick leave due to musculoskeletal disorders: findings from an occupational cohort study
Authors: Killingmo Rikke Munk , Tveter Anne Therese , Pripp Are Hugo , Tingulstad Alexander , Maas Esther , Rysstad Tarjei , Grotle Margreth
Published: March 2024

Objectives

The objective was to identify modifiable prognostic factors of high societal costs among people on sick leave due to musculoskeletal disorders, and to identify modifiable prognostic factors of high costs related to separately healthcare utilisation and productivity loss.

Design

A prospective cohort study with a 1-year follow-up.

Participants and setting

A total of 549 participants (aged 18–67 years) on sick leave (≥ 4 weeks) due to musculoskeletal disorders in Norway were included.

Outcome measures and method

The primary outcome was societal costs aggregated for 1 year of follow-up and dichotomised as high or low, defined by the top 25th percentile. Secondary outcomes were high costs related to separately healthcare utilisation and productivity loss aggregated for 1 year of follow-up. Healthcare utilisation was collected from public records and included primary, secondary and tertiary healthcare use. Productivity loss was collected from public records and included absenteeism, work assessment allowance and disability pension. Nine modifiable prognostic factors were selected based on previous literature. Univariable and multivariable binary logistic regression analyses were performed to identify associations (crude and adjusted for selected covariates) between each modifiable prognostic factor and having high costs.

Results

Adjusted for selected covariates, six modifiable prognostic factors associated with high societal costs were identified: pain severity, disability, self-perceived health, sleep quality, return to work expectation and long-lasting disorder expectation. Depressive symptoms, work satisfaction and health literacy showed no prognostic value. More or less similar results were observed when high costs were related to separately healthcare utilisation and productivity loss.

Conclusion

Factors identified in this study are potential target areas for interventions which could reduce high societal costs among people on sick leave due to musculoskeletal disorders. However, future research aimed at replicating these findings is warranted.

Trial registration number

NCT04196634, 12 December 2019.
A physical model test for the stress and deformation analyses in underground caverns containing block during excavation
Authors: Huang Tianzhu , Li Jianlin , Wang Lehua , Xu Xiaoliang , Shi Weizheng
Published: March 2024

To investigate the influence of block on the stress and deformation of underground cavern with high sidewall during excavation and unloading, a physical model test of an underground cavern containing block was conducted based on similarity theory. The response pattern of surrounding rock stress and displacement during excavation is analyzed, and the influence and mechanism of block on surrounding rock stress and deformation are revealed. Results show that stress conduction in the model is closely related to the structural plane during loading. The stress barrier and stress concentration phenomena occur when stresses pass through the structural plane. After the model is loaded, stress loss takes place when stresses are transmitted from the boundary to the interior. During the underground cavern excavation, the tangential stress of the surrounding rock decreases within a certain range of the sidewall and increases at both the top and the shoulder of the arch. The change rate of stress before and after excavation is used as an index to determine the surrounding rock stress zone, and the influence range caused by excavation is 2.0–2.5 times the cave span. Compared with the sidewall without block, the sidewall with block has a smaller radial stress unloading zone and a larger tangential unloading zone.
Towards a possible solution to the Hubble tension with Horndeski gravity
Authors: Tiwari Yashi , Ghosh Basundhara , Jain Rajeev Kumar
Published: March 2024

The Hubble tension refers to the discrepancy in the value of the Hubble constant $$H_0$$

H
0

inferred from the cosmic microwave background observations, assuming the concordance $$\Lambda $$
Λ
CDM model of the Universe, and that from the distance ladder and other direct measurements. In order to alleviate this tension, we construct a plausible dark energy scenario, within the framework of Horndeski gravity which is one of the most general scalar–tensor theories yielding second-order equations. In our set-up, we include the self-interactions and nonminimal coupling of the dynamical dark energy scalar field which enable very interesting dynamics leading to a phantom behaviour at low redshifts along with negative dark energy densities at high redshifts. These two features together make this model a promising scenario to alleviate the Hubble tension for appropriate choices of the model parameters. Towards a consistent model building, we show that this set-up is also free from both the gradient and ghost instabilities. Finally, we confront the predictions of the model with low redshift observations from Pantheon, SH0ES, cosmic chronometers and BAO, to obtain best fit constraints on model parameters.
An analytical approximation of the evolution of the primordial curvature perturbation in the ultraslow-roll inflation: an extended study
Authors: Zhao Ji-Xiang , Li Nan
Published: March 2024

Cosmic inflation can enter an ultraslow-roll (USR) stage, if there is a plateau on the inflaton potential. During this stage, the primordial curvature perturbation $${{\mathscr {R}}}_k$$

R
k

and its power spectrum $${{\mathscr {P}}}_{{\mathscr {R}}}$$

P
R

can be remarkably enhanced on small scales. In this work, an analytical approximation is provided to systematically study the evolution of $${{\mathscr {R}}}_k$$

R
k

in the USR inflation. We first discuss the asymptotic solutions of the moduli and arguments of $${{\mathscr {R}}}_k$$

R
k

and its time derivative $${{\mathscr {R}}}_{k,N}$$

R

k
,
N

on the sub- and super-horizon scales separately and find that all these solutions have simple exponential forms. Then, $${{\mathscr {R}}}_k$$

R
k

on five typical scales are investigated in order. Our analytical approximation predicts that $${{\mathscr {R}}}_k$$

R
k

first revolves around the origin in the complex plane, but if it crosses the horizon around the start of the USR stage, there appears a subsequent linear evolution towards or away from the origin. This behavior naturally explains the shape of $${{\mathscr {P}}}_{{\mathscr {R}}}$$

P
R

from the sharp dip to the peak and matches the numerical results perfectly. Moreover, the minimum of $${{\mathscr {P}}}_{{\mathscr {R}}}$$

P
R

is exactly proved to be nonvanishing. Our analytical approximation will help the model building in primordial black hole and gravitational wave physics.
Impacts of molecular characteristics on induced Knudsen force in the micro gas sensor
Authors: Shiryanpoor Iman , Valipour Peiman , Gerdroodbary M. Barzegar , Shahbazi Mohamadmahdi , Abazari Amir Musa
Published: March 2024

The development of the micro-gas sensor for the pressure measurement of the different gas species in the low-pressure domain is an important phenomenon. This paper has investigated the importance of molecular characteristics of the eight different gas species in various pressure domains. Impacts of molecular weight, molecular diameter and viscosity of the selected eight gas species on the induced Knudsen force have been analyzed. This study has employed Direct simulation Monte Carlo (DSMC) results of simulations of the micro-gas sensors for the evaluation of the micro-sensor performance in different gas species. Our investigation shows that the influence of molecular diameter change in the high-pressure domain would result in higher significant Knudsen force change. Knudsen force is also reduced when the value of the gas viscosity is increased.
Entrainment and mixing of unsteady gravity currents in compound channels
Authors: Vahed Elnaz , Khosravi Milad , Javan Mitra
Published: March 2024

Compound channels are a common hydraulic section of many alluvial and fluvial systems, serving as conduits for the flow of water and sediment. The proper design of these structures requires an understanding of the entrainment and mixing mechanisms in them. This paper presents a three-dimensional numerical study of lock-exchange flow in a compound channel covering the Reynolds numbers (Re) range of 17[Formula: see text]000–39[Formula: see text]000. This study investigates flow structures and mixing patterns for various geometries and flow characteristics. The results show that the entrainment coefficient decreases as the dense flow progresses, and the amplitude of instantaneous mixing fluctuations decreases with an increase in the width of the floodplain and reduced gravity. The averaged flux entrainment profiles show a minimum at [Formula: see text] at different times in the front area. In the head area also, a downward concavity can be seen in the profiles around [Formula: see text]. This study also reveals that changes in floodplain height do not affect the establishment of lobe-and-cleft instability. The wider the floodplain channel, the larger the lobe-and-cleft instability created. Small-scale mixing dominates at high Reynolds numbers, leading to higher fluid mixing.
THE EFFECTS OF THE EU ANTI-DUMPING MEASURES ON CHINESE-LISTED EXPORTERS — A MESOECONOMIC PERSPECTIVE
Authors: WANG SHUYING , YOU YILING , WANG CHAO , ZUO XIYA
Published: March 2024

Based on outcomes derived from a mesoeconomic model, this study examines the impact of European Union (EU) anti-dumping (AD) measures on listed Chinese exporters using the Propensity Score Matching with Difference-in-Differences (PSM-DID) method. Using yearly transaction data covering all Chinese listed exporters over 2000–2015, our findings indicate that EU AD measures result in a reduction in export volume and an increase in export prices for Chinese listed exporters at the product level. This trade-dampening effect is attributed to a significant decrease in export volume per exporter rather than the exit of listed exporters from the EU market. Additionally, we find that the effects of AD measures on the export volume and price of Chinese-listed exporters do not persist beyond the first year of the imposition of AD duties.
TRANSITION TO A GREEN ECONOMY: THE LINK BETWEEN POLITICAL UNCERTAINTY AND CARBON EMISSIONS
Authors: WEI HONGHONG , KHANAL UTTAM
Published: March 2024

This paper investigates the environmental consequences of political uncertainty due to terrorism using a panel dataset of 158 economies from 1995 to 2020. The empirical findings show that terrorist activities lead to lower levels of carbon dioxide emissions, with severe terrorist activities having quantitatively larger impacts. This paper further analyzes the heterogeneity of impact across economies from two distinct perspectives, involving disaggregation by the level of democracy and by the political stability of economies. Results suggest that economies with a low democracy level and fragile situation are characterized by a significant impact of terrorism on carbon emissions. However, the impact on democratic and politically stable economies is insignificant.
Perspective Collaboration for Multi-Domain Fake News Detection
Authors: Li Hui , Jiang Yuanyuan , Li Xing , Wang Chenxi , Chen Yanyan , Li Haining
Published: March 2024

Fake news is widely spread on social media. Much research works have been done on automatic fake news detection in single domain. However, fake news exists in various domains, so the detection model based on single domain is less effective in multiple domain scenes. To improve the detection ability of multi-domain fake news, we propose a perspective collaboration for multi-domain fake news detection (PCMFND) method to detect fake news across multiple domains by combining the powerful feature extraction ability of expert systems. The method extracts features of different perspectives from news content separately, then interactively combines the features of different perspectives, and ultimately achieves fake news detection by adaptively aggregating features of each perspective through domain knowledge. The effectiveness of the proposed method is demonstrated through comparison experiments with traditional multi-domain detection methods on Chinese and English multi-domain datasets.
Few-Shot Text Classification with an Efficient Prompt Tuning Method in Meta-Learning Framework
Authors: Lv Xiaobao
Published: March 2024

Meta-learning stands as a prevalent framework utilized in few-shot learning methods. Nonetheless, its efficacy hinges on substantial data availability during meta-training. Recent work adeptly tackled this hurdle by synergizing prompt tuning with the meta-learning paradigm, consequently attaining unparalleled performance on four benchmarks (FewRel, HuffPost, Reuters and Amazon). Nonetheless, the implementation efficacy of the previous method leaves room for enhancement, which is especially crucial when tuning larger language models. To this end, we introduce another expedited prompt tuning approach nested within the meta-learning framework. The novel approach normalizes the label information and sample information and uses the regression method to obtain the closed-form solution of each few-shot task, which significantly enhances inference speed, achieving a twofold improvement, while concurrently elevating average accuracy by [Formula: see text]% on the same benchmarks. Moreover, it demonstrates enhanced stability when faced with limited meta-training data, which is more applicable in many real scenarios where parallel data is rare. The source code is available to reproduce the results (http://github.com/Dr-Lv/EMPT).
An Analysis of Hierarchical Routing Strategy with Advanced Additional Sensors in WSNs
Authors: Xing Dongmei
Published: March 2024

Two kinds of sensors will be discussed in some sort of wireless sensor networks (WSNs). One is named a normal sensor (called A_nodes) with fixed initial energy, which can get perception data from the surrounding environment and have functions of storage and forwarding. The other is named relay sensor (called B_node) with sufficient energy, which only can store data and forward data. Cluster heads (called A_heads) are chosen among A_nodes by probability mode to create clusters first. Local adjustments would be done inter-cluster. Then the sink is selected as the root and a backbone shortest path tree with hops limited is built dynamically from A_heads, B_Nodes and sink. Inside the backbone shortest path aggregation tree, two steps are done. The first step, select some B_node as cluster head (denoted as B_node) and make local adjustment intra-clusters if it is possible. The second step, adjust the shortest path aggregation tree. By using both particle swarm optimization (PSO) and ant colony optimization (ACO), a traveling salesman problem (TSP) cycle with shorter path length is obtained (this method is noted as TSP_PSO_ACO). This TSP cycle consists of all nodes in the aggregation backbone tree. Along this cycle, energy is offered to nodes except sink. The above strategy would be discussed for its feasibility and time complexity. The experimental results imply that the energy consumption is reduced by using local adjustment. The relative failure rate of nodes can be reduced in the later stage of WSN survival. Offering energy to a small number of nodes several times has no obvious impact on the overall energy consumption and survival time of WSN. The case with some small-sized obstacles in WSN area is also discussed. There are little affections on TSP cycles both from results on theoretical analysis and simulation if there are some obstacles with small size in WSN area.
Analysis of the Motion Postures in Equestrian Sports Based on Multi-Sensor Data Fusion
Authors: Yang Yi , Yu Yaoyao , Chen Xinyue , Li Jie
Published: March 2024

Horse riding, in its essence, is both an art and a captivating sport. In these events, riders showcase their refined skills and deep bond with their horses, most notably through changes in physical positioning. This research aims to accurately capture and analyze the spatial postures of riders in equestrian sports, exploring the dynamic differences between professional and amateur riders. To achieve this, we employed a multi-sensor data fusion approach based on human kinetics theories, enhanced by an extended Kalman filter. This method, combined with an optical tracking system, enabled us to intricately compare and analyze the 3D postures of riders during walking and trotting phases. Our research captured these nuanced postural shifts using an inertial sensor network, yielding nine-axis motion data of riders during their performance. The accuracy of our fusion technique was validated using the optical tracking system. By analyzing the motion data, we discerned posture variations among the riders of differing expertise levels, even when executing the same riding technique. The insights from this research offer a quantifiable metric for refining equestrian training and contribute to understanding the complex dynamics of rider–horse interaction.
Pinball-OCSVM for Early-Stage COVID-19 Diagnosis with Limited Posteroanterior Chest X-Ray Images
Authors: Sonbhadra Sanjay Kumar , Agarwal Sonali , Nagabhushan P.
Published: March 2024

The conventional way of respiratory coronavirus disease 2019 (COVID-19) diagnosis is reverse transcription polymerase chain reaction (RT-PCR), which is less sensitive during early stages; especially if the patient is asymptomatic, which may further cause more severe pneumonia. In this context, several deep learning models have been proposed to identify pulmonary infections using publicly available chest X-ray (CXR) image datasets for early diagnosis, better treatment and quick cure. In these datasets, the presence of less number of COVID-19 positive samples compared to other classes (normal, pneumonia and Tuberculosis) raises the challenge for unbiased learning of deep learning models. This learning problem can be considered as one-class classification problem where the target class samples are present and other classes are absent or ill-defined. All deep learning models opted class balancing techniques to solve this issue; which however should be avoided in any medical diagnosis process. Moreover, the deep learning models are also data hungry and need massive computation resources. Therefore, for quicker diagnosis, this research proposes a novel pinball loss function based one-class support vector machine (PB-OCSVM), that can work in presence of limited COVID-19 positive CXR samples (target class or class-of-interest (CoI) samples) with objectives to maximize the learning efficiency and to minimize the false predictions. The performance of the proposed model is compared with conventional OCSVM and recent deep learning models, and the experimental results prove that the proposed model outperformed state-of-the-art methods. To validate the robustness of the proposed model, experiments are also performed with noisy CXR images and UCI benchmark datasets.
Model-Driven Approach for Making Citizen Science Data FAIR
Authors: Luna Reynaldo Alvarez , Garrigós Irene , Zubcoff Jose , González-Mora César
Published: March 2024

Citizen Science (CS) initiatives have proliferated in different scientific and social fields, producing vast amounts of data. Existing CS projects usually adopt PPSR Core as a data and metadata standard. However, these projects are still not FAIR (Findable, Accessible, Interoperable and Reusable)-compliant. We propose to use DCAT as a data and metadata standard since it helps to improve the interoperability of CS data catalogs and all the FAIR features. For this purpose, in this paper we present a model-driven approach to make CS data FAIR. Our approach has the following contributions: (i) the definition of a metamodel based on PPSR Core, (ii) the definition of a DCAT profile for CS, (iii) a definition of set of automated transformations from PPSR Core to DCAT. Finally, the implementation of the model-driven process has been validated by evaluating several FAIR metrics. The results show that our proposal has significantly improved the FAIR quality of CS projects.
Ulrich ideals in the ring k[[t5,t11]]
Authors: Endo Naoki , Goto Shiro , Iai Shin-ichiro , Matsuoka Naoyuki
Published: March 2024

The Ulrich ideals in the semigroup rings [Formula: see text] and [Formula: see text] are determined, by describing the normal forms of systems of generators, where [Formula: see text] denotes the formal power series ring over a field k.
Can we distinguish dark energy from vacuum-decaying models?
Authors: Barboza Edésio M. , Oliveira Lázaro J. S. , Soares Bráulio B.
Published: March 2024

In this paper, we study the distinguishability of dark energy and vacuum decay models. We start showing formally that dark energy fluids and dynamic vacuum are kinematically equivalent. Consequently, cosmological probes, such as the distances of type Ia supernovae (SNe Ia), cosmic microwave background (CMB) distance priors, baryon acoustic oscillations (BAO) distilled parameters and cosmic chronometers, are unable to allow us to distinguish such models from each other. Then, we show that, at least in principle, these models are dynamically distinguishable. So, dynamical probes, such as the evolution of linear matter perturbations, can be used to distinguish between dark energy models and dynamic vacuum models. To exemplify the kinematic equivalence between dark energy models and vacuum decay models, we study two simple models: the wCDM, commonly associated with dark energy, and the Wang–Meng model, often associated with dynamic vacuum. We test these two models with 22 measurements of [Formula: see text]. First, we consider both as dark energy then we consider both as vacuum decay. We show that, although compatible with each other, when seen as dynamical vacuum both models are tightly close to the [Formula: see text]CDM model.
Primary superconductivity in regular rotating electrically charged compact objects
Authors: Dymnikova Irina
Published: March 2024

In this paper, we refer to the early hypotheses on superconductivity in the models of the electron as an extended particle, and show how Nonlinear Electrodynamics minimally coupled to Gravity (NED-GR) predicts, without additional assumptions, the existence of primary superconductivity as the universal property of regular electrically charged rotating black holes and electromagnetic spinning solitons, replacing naked singularities and including that with the parameters of the electron. NED-GR dynamical equations describe basic generic properties of these objects in a self-consistent and the model-independent way, and establish the existence of the superconducting ring current in their deep interiors, which presents the non-dissipative source of the electromagnetic field of an object and provides its practically unlimited life time.
Effect of the pairing types and pairing strength on the ground state properties of even and odd Mg isotopes
Authors: Hasan Malik A. , Taqi Ali H. , Radhi R. A.
Published: March 2024

This study is an investigation of the effect of the pairing strength using different types of pairing (surface, volume and mixed surface–volume pairing) on the ground state properties of even and odd Mg isotopes. The Hartree–Fock–Bogoliubov (HFB) theory and two types of Skyrme forces, SKI3 and SLY6, were employed in our calculations. The pairing strength values are modified at each execution of the HFBTHO code to obtain the experimental values of binding energy for the investigated even and odd isotopes separately. Then a new formula for pairing strength for each even and odd isotope independently for all the pairing, surface, volume and mixed surface–volume types is developed by fitting the pairing strength values to the mass number. Based on the newly generated formulas for pairing strength, some of the calculated ground state properties are found to depend strongly on the pairing strength values and the pairing type also plays an essential role in providing accurate results.
Dynamic Analysis of a Double-Cable-Stayed Shallow Arch Model Under Multi-Frequency Excitation by IHB Method
Authors: Cong Yunyue , Jin Shiyu , Kang Houjun
Published: March 2024

To reveal the dynamic properties of cable-stayed bridges under complex external excitations, a double-cable-stayed shallow arch model induced by multi-frequency harmonic excitations is established. The cable and shallow arch exhibit primary or subharmonic resonances by sweeping excitations simultaneously and asynchronously. Galerkin method, one/two time scales Incremental Harmonic Balance (IHB) method, and Runge–Kutta (RK) method are applied to explore the nonlinear dynamic responses. Research results demonstrate that both the cables and shallow arch present soft and hard spring properties, despite the very weak hard spring of the shallow arch; one-way dynamic interaction among the cables and the shallow arch is discovered when sweeping excitations asynchronously.
Nonlinear Optimized PID Vibration Control of Thermal-Dependent FG Composite Porous Plates Reinforced by Agglomerated CNTs
Authors: Li Juan , Liu Juanyin
Published: March 2024

This research study aims to delve into the effects of carbon nanotubes (CNTs) agglomeration on the dynamic characteristics of smart functionally graded (FG) porous sandwich plates. The structure of the sandwich plate comprises a core layer that incorporates dispersed CNTs within a polymer matrix. In addition, two layers are equipped with piezoelectric sensors and actuators. The agglomeration of CNTs is mathematically modeled using the Eshelby–Mori–Tanaka approach, accounting for both complete and partial agglomeration states. Moreover, the study takes into account the thermal-dependent behavior of CNTs. Subsequently, an optimal nonlinear proportional-integral-derivative (PID) control scheme based on the Bat optimization algorithm is applied to mitigate vibrations within the composite structure. Unlike the fixed gains of the classical PID, the nonlinear version dynamically adjusts its parameters in real time, ensuring enhanced responsiveness and stability. Furthermore, a comprehensive numerical investigation is conducted to assess the impact of several parameters on the natural frequencies in the frequency domain. These parameters encompass porosity distributions, porosity coefficients, reinforcement patterns, weight fractions of nanofillers, temperature, and the agglomeration of CNTs. The vibration attenuation performance of both nonlinear and classical PID controllers is evaluated through numerical simulations. The findings indicate the robustness and rapid disturbance rejection of the proposed control scheme.
Nonlinear Geometrical Effect on Deflection Characteristics of Fiber/Metal Laminates
Authors: Panda Bhabatosh , Kumar Vikash , Meher Ashish Kumar , Panda Subrata Kumar
Published: March 2024

The deflection behavior of the fiber-metal laminated structures is envisaged in this research using higher-order deformation kinematics and large (finite) deformations of geometries via Green–Lagrange strain. The panel governing equation is derived using variational principle and solved numerically considering the nonlinear finite element (FE) steps. The necessary responses are obtained using in-house MATLAB computer code and compared with an in-house simulation model (prepared in ANSYS) and experimental data (using in-house experimental set-up). The results are verified and agree with the published data available in the open domain. The proposed model results show better consequences compared to the simulation results. The detailed responses are computed for the variable geometrical conditions (i.e. aspect ratio, end support, side-to-thickness ratio), loading and stacking sequences, including the metal layer placing. The inferences indicate the importance of nonlinearity in the framework of a higher-order kinematic model for analysing the metal laminated structure.
Numerical Study on Seismic Performance of Rocking Self-Centering (RSC) Bridge Piers Under Bidirectional Excitation
Authors: Jiang Li , Ge Chao-Yang , Zhou Peng-Cheng , Sun Zhi-Guo , Liu Jia-Jun , Liu Yan-Hui , Wang Dong-Sheng , Ge Xiao
Published: March 2024

To study the seismic performance of rocking self-centering (RSC) bridge piers, a numerical model of RSC pier is established based on the OpenSees platform. The model is verified by experimental results. The seismic performance of RSC piers is analyzed under quasi-static and seismic loads, respectively, in terms of peak lateral drift, residual deformation, compressive zone height of the cross-section and tendon stress. Far-field, near-field without pulse and near-field pulse-like ground motion records are selected for the time-history analysis. The effects of prestressing tendon reinforcement ratio, energy-dissipating bar ratio and axial load are examined, respectively. The results show that the strength of the RSC pier, the depth of the compressive zone of the cross-section and the self-centering capacity increase with increasing prestressing tendon reinforcement ratio. When the energy-dissipating reinforcement ratio exceeds 1%, the boost of seismic performance of the pier becomes insignificant. The increasing axial load can increase the lateral strength of the pier. However, it could lead to premature yielding of the prestressing tendons.
Doubly reflected BSDEs driven by RCLL martingales under stochastic Lipschitz coefficient
Authors: Elmansouri Badr , El Otmani Mohamed
Published: March 2024

In this paper, we study a backward stochastic differential equation driven by a Right Continuous with Left Limits (RCLL) martingale with two completely separated RCLL barriers. When the coefficient is stochastically Lipschitz, we demonstrate the existence and uniqueness of a square-integrable adapted solution using the penalization method.

Additionally, we provide a fair price for a game contingent claim between two traders with additional exogenous knowledge of the same stock price in a public financial market driven by an Azéma’s martingale. We also determine a saddle point for the game when the obstacles are left upper semi-continuous along stopping times.
Uncountable groups with small commutator subgroup
Authors: De Falco M. , Musella C. , Sabatino G.
Published: March 2024

This paper continues the investigation of the behavior of the commutator subgroup of an uncountable group whose large subgroups have finite (bounded) index in their normal closures. Moreover, uncountable groups in which all large subgroups have small index in their normal closures are considered.
Localization of energies in Navier–Stokes models with reaction terms
Authors: Kohr Mirela , Precup Radu
Published: March 2024

We analyze a general class of coupled systems of stationary Navier–Stokes type equations with variable coefficients and non-homogeneous terms of reaction type in the incompressible case. Existence of solutions satisfying the homogeneous Dirichlet condition in a bounded domain in [Formula: see text], [Formula: see text], and localization results for the corresponding kinetic energy and enstrophy are obtained by using a variational approach and the fixed point index theory.
Exploring the deceleration parameter in f(T) gravity: A comprehensive analysis using parametrization techniques and observational data
Authors: Chaudhary Himanshu , Bouali Amine , Duru Hülya , Güdekli Ertan , Mustafa G.
Published: March 2024

In this paper, we employ parametrization techniques within the framework of [Formula: see text] gravity to investigate the deceleration parameter (DP), a key quantity characterizing the universe’s expansion dynamics. By analyzing the DP, we gain valuable insights into the nature of cosmic constituents and their impact on the universe’s evolution. We utilize a combination of observational data, including 31 Cosmic Chronometers (CC) measurements, 1048 Type Ia Supernovae (SNIa), 17 Baryon Acoustic Oscillation (BAO) measurements, Cosmic Microwave Background (CMB), 162 Gamma Ray Bursts (GRB), and 24 observations of compact radio quasars (Q). We employ the Markov chain Monte Carlo (MCMC) sampling technique to estimate the best-fit range of model parameters. Cosmological and cosmographic parameters are investigated, and their implications in the context of cosmology have been discussed. We also analyze the statefinder and Om diagnostic to gain deeper insights into the universe’s behavior. Furthermore, we conduct statistical analyses to compare our model with the standard [Formula: see text]CDM model. Our investigation also includes the study of physical parameters, providing comprehensive insights into the cosmological behavior within the [Formula: see text] gravity framework. The results and comparisons presented in this work contribute to a deeper understanding of the universe’s dynamics and provide valuable implications for the cosmological model under consideration.
Bouncing universe scenario in f(Q,T) gravity model
Authors: Davood Sadatian S. , Mohamad Reza Hosseini S.
Published: March 2024

In this paper, we investigate the bouncing universe in a modified gravity model [Formula: see text]. The bouncing universe theory posits that the universe goes through periodic expansions and contractions, with a “bounce” occurring at the end of each contraction that leads to a new expansion. This theory suggests that our universe didn’t emerge on its own out of nothing, but is instead the latest in a series of universes that have been expanding and contracting for eternity. It has gained renewed interest in recent years as a potential alternative to the Big Bang theory, which suggests that our universe began with a massive expansion from a singularity. According to the above explanations, first, we review of [Formula: see text] gravity model, then the bouncing universe scenario according to the [Formula: see text] gravity model in some special functions is analyzed in detail. We find that in which condition of parameters space, bouncing occurs.
Energy density inhomogeneities with self-gravitating charged fluid in modified teleparallel gravity
Authors: Bhatti M. Z. , Turki Nasser Bin , Hanif S. , Malik A.
Published: March 2024

In this paper, we analyze energy density inhomogeneities for charged fluid configuration in the background of [Formula: see text] theory and recognize its prime features as computed in GR. The dynamical equations are composed employing Bianchi identities for the standard, [Formula: see text] extra terms, and energy-momentum tensor for the electromagnetic field. We evaluate various mathematical models of dissipative and anisotropic fluid distributions in-plane symmetry under [Formula: see text] gravity. To proceed with the investigation, we design the [Formula: see text] field equations, kinematical quantities, and mass function. We analyzed dynamical variables and Ellis equations in terms of our considered theory. To examine the associated inhomogeneity factors, specific scenarios are illustrated alongside and without dissipation. Within a non-radiating situation, we analyze dust and isotropic and anisotropic matter in the state of electric charge. We examine the inhomogeneity factor of a dissipative fluid via a charged dust haze. We derive that the electromagnetic field fosters matter inhomogeneity, but additional curvature factors make the entire structure more homogenous as time passes.
Perfect fluid locally rotationally symmetric Bianchi Type-I spacetimes admitting concircular vector fields in f(T) gravity
Authors: Khan Suhail , Shah Syed Majid , Ali Ahmad Tawfik , Jamal Sameerah
Published: March 2024

We obtained the solutions of Einstein’s Field Equations (EFEs) for locally rotationally symmetric (LRS) Bianchi type-I perfect fluid spacetimes through the concircular vector fields (CCVFs) in [Formula: see text] gravity. It is shown that such metrics admit CCVFs of 4, 5, 6, 7, 8 and 15 dimensions. We also calculated the energy density, fluid pressure, torsion scalar [Formula: see text] and the form of the function [Formula: see text]. We did not specify the form of [Formula: see text] for the solution of EFEs but found a particular form of [Formula: see text] during the process of finding the CCVFs. It is observed that energy density and fluid pressure of some solutions are related as [Formula: see text], which means that the universe represented by these spacetime metrics behaves like dark energy models. For other solutions, it is observed that the fluid pressure and energy density can remain positive for particular choices of the constants involved. Thus, in these cases the rate of expansion can slow down due to positive attractive effect. We also calculated the Hubble’s parameter ([Formula: see text]), scalar expansion ([Formula: see text]), shear scalar ([Formula: see text]), anisotropy parameter ([Formula: see text]) and the deceleration parameter ([Formula: see text]) associated with each of the obtained exact LRS Bianchi type-I solutions. It is observed that the physical behavior of the spacetime changes with the number of admitting CCVFs. A constant anisotropic behavior for 15-dimensional CCVFs is observed to change to isotropic nature for seven-dimensional CCVFs.
On motives of parabolic Higgs bundles and parabolic connections
Authors: Roy Sumit
Published: March 2024

Let [Formula: see text] be a compact Riemann surface of genus [Formula: see text] and let [Formula: see text] be a fixed finite subset. We considered the moduli spaces of parabolic Higgs bundles and of parabolic connections over [Formula: see text] with the parabolic structure over [Formula: see text]. For generic weights, we showed that these two moduli spaces have equal Grothendieck motivic classes and their [Formula: see text]-polynomials are the same. We also show that the Voevodsky and Chow motives of these two moduli spaces are also equal. We showed that the Grothendieck motivic classes and the [Formula: see text]-polynomials of parabolic Higgs moduli and of parabolic Hodge moduli are closely related. Finally, we considered the moduli spaces with fixed determinants and showed that the above results also hold for the fixed determinant case.
Mechanical Response of New Configurations Formed After Rotation of Triple Intermittent Nested Ring
Authors: Huang Ying , Sun Bo-Hua
Published: March 2024

Nested ring energy absorbers absorb most of the kinetic energy of an impact in an irreversible manner, reducing the damage to the human body or cargo inside the carrier in a collision. Compared to conventional single ring, nested ring can greatly increase the specific energy absorption (SEA) without significantly increasing the cost. This paper proposes a new design idea for the nested ring structure, which forms a new design by rotating the traditional configuration. Since the symmetry is broken, the deformation mode is asymmetric. Both experimental tests and finite element simulations are performed. The experimental results match the simulation results with less than 5% deviation, demonstrating the new design improves energy absorption capacity by 7% compared to previous nested ring designs.
Parameter Analysis of Vibration Damping and Energy Harvesting Performance of Bionic Suspension
Authors: Guan Dong , Wu Jiangdong , Li Jing , Yang Zhengwei , Yurchenko Daniil
Published: March 2024

The traditional damping structure usually transfers the vibration energy into heat, dissipated and without harvesting. But for harsh environments, such as military activities and lunar probe patrols, the vibration energy can be extracted, and realize the purpose of self-power condition monitoring. In this paper, a bionic suspension with energy-harvesting property is proposed based on bionic configurations. The bionic suspension adopts a symmetrical three-link arrangement to simulate the arrangement of bones, and a horizontal spring to simulate muscles. The micro-generator embedded in the knee joint provides the main damping force for the overall structure and also plays a role in harvesting energy. The dynamic equation and virtual prototype model are established, and the effects of parameter changes on the performance of vibration reduction and energy harvesting are analyzed, and the relationship between the two is revealed. The results show that the parameters to achieve their respective optimal performance are not consistent in the trend, though it is difficult to obtain the best performance of both, it can be designed according to the specific functions to be satisfied. This structure can be utilized as a general model for vibration reduction and energy harvesting scenarios, providing new ideas for self-powered sensing and condition monitoring configurations.
Weighted variational inequalities on Hadamard manifolds
Authors: Singh Nagendra , Iqbal Akhlad , Ali Shahid
Published: March 2024

In this study, we extend the weighted variational inequality problem (WVIP) and the Minty weighted variational inequality problem (MWVIP) from linear spaces to nonlinear spaces, specifically Hadamard manifolds, and show the relationships between WVIP and vector variational inequalities. In addition, we establish the concept of weighted monotonicities on the Hadamard manifold and prove the existence of many solutions.
A fixed point result for DND-convex-power condensing mappings
Authors: García G.
Published: March 2024

In this paper, based on the so-called degree of nondensifiability (DND), we introduce the concept of DND-convex-power condensing mapping which generalizes that of the DND-condensing one. A fixed point result for this new class of mappings is proved, and with some examples we evidence the differences between it and other fixed point theorems of the same type. As application of our results, we prove under suitable conditions the existence of fixed point for the superposition operator, defined in the Banach spaces of the continuous functions from [Formula: see text] and with values in a Banach space.
On the divisor graph of some graph operations
Authors: Rastgar Zinat , Khashyarmanesh Kazem , Afkhami Mojgan
Published: March 2024

In this paper, we investigate when the generalized join product, generalized corona product, generalized edge corona product and the Kronecker product of graphs are divisor graphs. Also the situations under which the zero divisor graph and the co-maximal graph are divisor graphs are characterized.
A study on regularity and reduction for n-ary semihypergroups
Authors: Nongmanee Anak , Leeratanavalee Sorasak
Published: March 2024

In this paper, we construct new [Formula: see text]-ary semihypergroups induced by subsets of the base sets of [Formula: see text]-ary semigroups. Then, we investigate some algebraic connections between the [Formula: see text]-ary semihypergroups and [Formula: see text]-ary semigroups via the concept of regularity on [Formula: see text]-ary semihypergroups. We also discover some significant conditions on [Formula: see text]-ary semihypergroups which can be reduced to semihypergroups.