bluuebunny/crossref_metadata_2025_split huggingface dataset:
A multiscale anisotropic polymer network model coupled with phase field fracture
Authors: Arunachala Prajwal Kammardi , Abrari Vajari Sina , Neuner Matthias , Sim Jay Sejin , Zhao Renee , Linder Christian 
Published: April 2024

AbstractThe study of polymers has continued to gain substantial attention due to their expanding range of applications, spanning essential engineering fields to emerging domains like stretchable electronics, soft robotics, and implantable sensors. These materials exhibit remarkable properties, primarily stemming from their intricate polymer chain network, which, in turn, increases the complexity of precisely modeling their behavior. Especially for modeling elastomers and their fracture behavior, accurately accounting for the deformations of the polymer chains is vital for predicting the rupture in highly stretched chains. Despite the importance, many robust multiscale continuum frameworks for modeling elastomer fracture tend to simplify network deformations by assuming uniform behavior among chains in all directions. Recognizing this limitation, our study proposes a multiscale fracture model that accounts for the anisotropic nature of elastomer network responses. At the microscale, damage in the chains is assumed to be driven by both the chain's entropy and the internal energy due to molecular bond distortions. In order to bridge the stretching in the chains to the macroscale deformation, we employ the maximal advance path constraint network model, inherently accommodating anisotropic network responses. As a result, chains oriented differently can be predicted to exhibit varying stretch and, consequently, different damage levels. To drive macroscale fracture based on damages in these chains, we utilize the micromorphic regularization theory, which involves the introduction of dual local‐global damage variables at the macroscale. The macroscale local damage variable is obtained through the homogenization of the chain damage values, resulting in the prediction of an isotropic material response. The macroscale global damage variable is subjected to nonlocal effects and boundary conditions in a thermodynamically consistent phase field continuum formulation. Moreover, the total dissipation in the system is considered to be mainly due to the breaking of the molecular bonds at the microscale. To validate our model, we employ the double‐edge notched tensile test as a benchmark, comparing simulation predictions with existing experimental data. Additionally, to enhance our understanding of the fracturing process, we conduct uniaxial tensile experiments on a square film made up of polydimethylsiloxane (PDMS) rubber embedded with a hole and notches and then compare our simulation predictions with the experimental observations. Furthermore, we visualize the evolution of stretch and damage values in chains oriented along different directions to assess the predictive capacity of the model. The results are also compared with another existing model to evaluate the utility of our model in accurately simulating the fracture behavior of rubber‐like materials.
Assessment of socio demographic factors on termination of pregnancy in Ghana
Authors: Armah‐Mensah Mavis Akosuah Serwah , Armah‐Mensah Isaac 
Published: April 2024

AbstractAimAssessing the socio‐demographic factors on termination of pregnancy in Ghana.DesignCross‐sectional study, using data source from the Demographic Health Survey (DHS).MethodsData pooled from the most recent DHS conducted in Ghana, with variables of interest with rural and urban population coverage. A systematic search of the literature was performed using PubMed, Google Scholar and Elsevier PubMed for the secondary data. Descriptive and logistic regression analysis was performed using Python Pandas' software to estimate the independent effects of the socio‐demographic factors on termination of pregnancy in Ghana.ResultsReported using odds and adjusted OR AOR at 95% confidence level and statistical significance at a p‐value of (p > 0.05). Age, place of residence, occupation, currently pregnant, woman's individual sample weight, completeness of current pregnancy, living children + current pregnancy, ethnicity and number of living children significantly predicted the outcome variable.Patient or Public ContributionNurses have an important role to play in providing support, education and counselling to people, and must be equipped with the knowledge and skills (including non‐judgmental and compassionate care) necessary to provide care that is sensitive to the diverse needs of people from different socio‐demographic backgrounds.
Intensification of polyethylene devolatilization in twin‐screw extruder with additives
Authors: Fang Zibin , Shuai Yun , Huang Zhengliang , Wang Jingdai , Yang Yongrong 
Published: April 2024

AbstractAiming at the problem of difficult to remove high‐carbon α‐olefin in polyethylene, the influences of operation conditions and devolatilization additives on the devolatilization of LLDPE/1‐octene system in an exhaust twin‐screw extruder are studied by headspace gas chromatography. The results showed that the devolatilization efficiency increases with the devolatilization temperature and vacuum. With the screw rotational speed, the content of liquid additives and the gas velocity of gas additives increasing, the devolatilization efficiency first increases and then decreases. The devolatilization difficulty of different grades of polyethylene varies due to the difference of the viscosities. When the volatile content is high, the effect of devolatilization additives is anhydrous ethanol > surfactant > water > nitrogen. When the volatile content is low, the effect of nitrogen on devolatilization is obviously better than anhydrous ethanol and water. Finally, a novel devolatilization process is proposed, that is, an evacuation system (vacuum degree 0.08–0.1 MPa) is set up in each stage of the devolatilization section, the anhydrous ethanol is introduced in the first stage, and high‐purity nitrogen is introduced in the second, third, and fourth stages, which can ultimately reduce the VOC content of LLDPE products to less than the target value of 50 ppm.Highlights
The devolatilization process is used to remove high carbon α‐olefins from LLDPE.
Each additive has an optimal injection value.
Ethanol is the most effective in the foam‐dominated devolatilization stage.
Nitrogen is the most effective in the diffusion‐dominated devolatilization stage.
A new additive‐enhanced twin‐screw extruder devolatilization process is proposed.
Evaluation of the impact of natural weathering on the properties of high‐density polyethylene bottles by experimental approach
Authors: Elkori Rabiaa , Lamarti Amal , El Had Khalid , Hachim Abdelilah , Yamari Imane 
Published: April 2024

AbstractThis work presents an in‐depth experimental study aimed at assessing the impact of natural weathering on the behavior of high‐density polyethylene (HDPE) bottles. To this end, several analytical techniques were employed, including Fourier transform infrared spectroscopy (FTIR) to examine molecular changes, scanning electron microscopy (SEM) to study morphology, thermogravimetric analysis (TGA) to assess thermal properties, and tensile and compression tests to evaluate mechanical properties. The results obtained reveal significant changes in HDPE exposed to natural weathering. FTIR analysis enabled us to identify that the HDPE bottles had been subjected to an oxidation process initiated by the absorption of solar radiation during natural weathering treatments, while SEM analysis showed the presence of holes resulting from the detachment of material fragments after exposure, TGA analysis confirms the impact of natural exposure time on the decrease in the average molecular weight and chemical degradation of HDPE macromolecules, through a reduction in the initial degradation temperature and the maximum thermodegradation temperature. However, tensile and compressive tests showed a reduction in the mechanical strength of HDPE after exposure to natural conditions, with notable variations depending on environmental conditions, making the material damaged. These results enabled us to calculate the damage caused by three damage laws. These results offer important insights into the mechanisms of HDPE degradation under the influence of natural climatic factors, paving the way for the development of more resistant and durable packaging materials in the face of variable environmental conditions.Highlights
The objective of this study is to analyze and describe the effects of natural weathering on high‐density polyethylene bottles. This involves evaluating the deterioration of physicochemical, mechanical, and morphological properties. Additionally, three damage laws are employed to assess the extent of damage inflicted by this material.
Analytical techniques were used, including SEM, FTIR, and TGA, tensile and compressive test.
Efficacy of arm crank ergometry on individuals with spinal cord injury: A systematic review of randomized controlled trials
Authors: Alashram Anas R. 
Published: April 2024

AbstractObjectivesTo investigate the efficacy of arm crank ergometry (ACE) on physical, psychological, and quality of life outcomes in individuals with spinal cord injury (SCI).Literature SurveyA comprehensive search was conducted on PubMed, Scopus, MEDLINE, Physiotherapy Evidence Database (PEDro), Web of Science, REHABDATA, and Embase from inception until July 2023.MethodologyStudies were included if the sample was composed of individuals with SCI, the intervention followed an ACE intervention, and the study was a randomized controlled trial including at least one outcome measure evaluating physical, psychological, or quality of life. The PEDro scale was used to assess the methodological quality of the included studies. The meta‐analysis was not feasible due to the heterogeneity in the treatment protocols and outcome measures among the selected studies.SynthesisOf 1013 articles, seven studies (n = 200), with 16% of participants being female, were included in this review. The scores on the PEDro scale ranged from 6 to 8, with a median score of 7. There were variations in treatment protocols and outcome measures, resulting in heterogeneous findings. The effects of the ACE interventions on physical, psychological, and quality of life outcomes showed inconsistency.ConclusionsACE training proves to be a suitable and safe intervention for individuals with traumatic SCI. Nevertheless, the existing evidence concerning its effects on physical, psychological, and quality of life outcomes in individuals with SCI is limited. Further trials are required to investigate the effects of various ACE training protocols on SCI populations.
Investigation of the effect of permeation and antifouling characteristics of hybrid poly(vinylidene fluoride) membranes tailored with ZIF‐67 metal–organic frameworks
Authors: Rameesha Laila , Rana Dipak , Nagendran Alagumalai 
Published: April 2024

AbstractHerein the ZIF‐67, a hydrophilic cobalt‐based zeolitic imidazolate framework is synthesized and incorporated with a poly(vinylidene fluoride) (PVDF) to fabricate hybrid ultrafiltration membranes by phase inversion method. The characteristics of PVDF/ZIF‐67 membranes are examined using different analytical techniques such as Fourier‐transform infrared spectroscopy, X‐ray diffractometer, scanning electron microscope, atomic force microscope, and contact angle analysis. The membrane performance is probed using pure water flux (PWF), bovine serum albumin (BSA), and humic acid (HA) rejection. The maximum water flux of 162.5 Lm2 h−1 with BSA and HA rejection of 97% and 98.2%, respectively, exhibited by 1.5 wt% ZIF‐67. The contact angle value is reduced from 83.5 to 58.6° indicating the increase in hydrophilic nature of PVDF membranes by the addition of ZIF‐67. The presence of ZIF‐67 in the PVDF membrane matrix showed outstanding anti‐bacterial properties against Escherichia coli and Staphylococcus aureus. Overall, the PVDF/ZIF‐67 ultrafiltration membranes demonstrate the potential for water treatment applications.
Experimental and molecular dynamics study on thermal‐mechanical properties of epoxy shape memory polymers
Authors: Yang Yawen , Liu Bei , Li Yufeng , Yin Haibin 
Published: April 2024

AbstractExperimental and molecular dynamics simulations were employed to investigate epoxy shape memory polymers' thermal‐mechanical properties and shape memory characteristics, utilizing polyether amine and modified hexanediamine as curing agents following the material prerequisites for variable stiffness fixtures. Glass transition temperature and Young's modulus of epoxy shape memory polymers are characterized by dynamic mechanical analysis. The consistency of the glass transition temperature between the simulation model and the experimental findings verified the accuracy of the molecular dynamics simulation. The uniaxial tensile simulation revealed that non‐bond energy predominantly exerts its influence in stretch. After reaching the yield stress, the weight fraction of the curing agent affects the generation of internal pores, with the yield stress of systems exhibiting substantial pores being minor. Systems characterized by a higher weight fraction of curing agents are more prone to pore formulation. Simulation of shape memory properties demonstrates that the entropy resulting from differences in molecular weight impacts the simulated system's shape fixation ratio and shape recovery ratio.
Preparation of CO2 responsive PVDF membranes using PDMAEMA‐PMMA‐PDEAEMA triblock copolymer
Authors: Luo Xin , Wang Zhuqing , Yan Mengxia , Xin Jianhui , Yang Yongqi , Zheng Longpo , Zhang Haijun 
Published: April 2024

AbstractCO2‐responsive based separation membranes are attractive in the field of membrane separation, not only for their ability to modulate the pore size of the membrane in response to CO2 stimulation, but also for their ability to facilitate the removal of contaminants from the membrane surface. However, the introduction of CO2‐responsive polymers by simple blending often results in membranes that are not responsive enough to last. In this study, we synthesized a hooked triblock copolymer and used it as an additive to prepare CO2‐responsive PVDF membranes. The modified membrane combines the advantages of the PVDF material with the CO2 response of the triblock copolymer. It not only has good CO2 responsiveness, but also removes organic contaminants from the membrane surface well. The water flux of the hybrid membranes is 4 to 11 times higher than that of pure PVDF membranes, indicating that the triblock copolymer also has some porogenic ability. Surprisingly, the static contact angle on the membrane surface increased from 67° to 86° with the increase of the triblock copolymer content in the PVDF membrane. This suggests that modified PVDF membranes have some potential in the field of switchable oil–water separation.
Impedance matching design of capacitively coupled plasma with fluid and external circuit coupled model
Authors: Zhao Lifen , Yu Shimin , Wang Yu , Chen Zili , Liu Xiangmei , Wang Hongyu , Jiang Wei , Zhang Ya 
Published: April 2024

AbstractThis paper establishes a fully self‐consistent coupled model of fluid and external circuits. The Kirchhoff equation, the charge conservation equation, and Poisson equation are coupled via boundary conditions and integrated into the fluid model for iterative parameter solution. On the basis of this model, we investigate the influence of impedance matching on single‐frequency capacitively coupled plasma characteristics under different parameters and topological structures. The findings suggest that after several iterations the matching parameters converge. Using different initial circuit parameters, the adjustable capacitance and inductance are eventually adjusted to approximately equal values, resulting in the same optimal matching state, whereas diverse discharge parameters led to different outcomes. Under fixed parameters for two topologies, the power absorption efficiency increases, and the reflection coefficient approaches zero, and the best matching is found. This model can be extended to different fluid programs to investigate the impact of complex external circuits with impedance matching network on plasma discharge while simultaneously seeking best impedance matching.
A New 2D Formulation of Modified General Relativity
Authors: Böhmer Christian G. , Jensko Erik 
Published: April 2024

AbstractIt is well known that the Einstein–Hilbert action in two dimensions is topological and yields an identically vanishing Einstein tensor. Consequently one is faced with difficulties when formulating a non‐trivial gravity model. The authors present a new, intrinsically two‐dimensional, approach to this problem based on the Einstein action. This yields a well defined variational approach which results in new field equations that break diffeomorphism invariance. This proposed approach does not require the introduction of additional scalar fields, nor the use of conformal transformations. However, how including conformal counter terms leads to equivalent results is shown. In doing so, an explanation for why previous approaches worked can be provided. Solutions to the field equations are briefly discussed.
Balance diagnostics in propensity score analysis following multiple imputation: A new method
Authors: Yucel Karakaya Sevinc Puren , Unal Ilker 
Published: April 2024

AbstractThe combination of propensity score analysis and multiple imputation has been prominent in epidemiological research in recent years. However, studies on the evaluation of balance in this combination are limited. In this paper, we propose a new method for assessing balance in propensity score analysis following multiple imputation. A simulation study was conducted to evaluate the performance of balance assessment methods (Leyrat's, Leite's, and new method). Simulated scenarios varied regarding the presence of missing data in the control or treatment and control group, and the imputation model with/without outcome. Leyrat's method was more biased in all the studied scenarios. Leite's method and the combine method yielded balanced results with lower mean absolute difference, regardless of whether the outcome was included in the imputation model or not. Leyrat's method had a higher false positive ratio and Leite's and combine method had higher specificity and accuracy, especially when the outcome was not included in the imputation model. According to simulation results, most of time, Leyrat's method and Leite's method contradict with each other on appraising the balance. This discrepancy can be solved using new combine method.
Analyzing the Temporal Behavior of Noisy Intermediate‐Scale Quantum Nodes and Algorithm Fidelity
Authors: Podda Carlo , Moreau Giuliana Siddi , Pisani Lorenzo , Leoni Lidia , Cao Giacomo 
Published: April 2024

AbstractIn the past decade, quantum computing has undergone rapid evolution, capturing the increasing interest of the scientific community, industry, and governments. This enthusiasm has resulted in ambitious growth plans which stimulate the development of more efficient quantum computing devices and programming environments. The easy accessibility of quantum platforms in the cloud has attracted individuals to explore quantum computing, prompting a comprehensive analysis and assessment of quantum device's behavior. The extensive benchmarking presented in this study involved all free available quantum computing devices within the IBM Quantum Platform. These devices are employed to execute tens of thousands of quantum program executions, with the objective of evaluating quantum computer behavior and performance over time and under different optimization options. Special emphasis has been placed on analyzing the transpile operation and the depth of generated quantum circuits. The machine analysis tests are conducted using Quantum Computing Run Assistant (QCRA), a versatile software tool specifically designed to streamline the effortless distribution of quantum programs across a range of quantum computing platforms. This software not only streamlines the optimization of benchmarking processes but also simplifies the assessment of different configurations and result quality through the collection of advanced job metadata.
The association between boredom and creativity in educational contexts: A scoping review on research approaches and empirical findings
Authors: Zeißig Anke , Kansok‐Dusche Julia , Fischer Saskia M. , Moeller Julia , Bilz Ludwig 
Published: April 2024

AbstractAssumptions around the association between boredom and creativity are contentious. Although studies suggest positive effects of boredom, it is also considered a negative predictor of creativity. Researchers also assume that creativity reduces boredom, but boredom can also occur during creative tasks. In this review, we identify and systematise the empirical evidence available to date on the association between creativity and boredom in educational contexts. The string‐guided electronic search yielded 2849 publications. Nineteen publications based on 27 empirical studies met the inclusion criteria. Two reviewers extracted definitions, theories, methods, operationalisations, measurement instruments, and outcomes from the studies using a coding scheme. We identified a range of different theoretical and methodological approaches. The largest cache of empirical evidence was obtained from experimental and quasi‐experimental studies (five positive associations, four negative, two contradictory, and three insignificant results). Correlation studies identified three negative, one contradictory, and seven insignificant correlations between boredom and creativity. In addition, two studies with exploratory, statistically not relevant results contributed to the body of research. The results from the identified and evaluated studies argue both for and against the sensitivity of creative processes in relation to boredom—but a clear causal, positive or negative effect of boredom on creativity is not currently supported by the empirical evidence available. Previous research has also not yet demonstrated an apparent effect of creative states or traits on academic boredom. Future research should aim to explore under what circumstances different relationships between boredom and creativity can be observed and reliably replicated.
Adaptive internal synchronization control of chaotic systems based on DNA strand displacement
Authors: Liu Xiaoxiao , Lv Hui 
Published: April 2024

AbstractIn the application of DNA‐based chaotic synchronization, the precise values of the system parameters are often complicated to attain due to the interference of external factors, thus weakening the performance of synchronization. In this paper, considering the case of unknown parameters in chaotic systems, a method of adaptive synchronization based on DNA strand displacement (DSD) is proposed. Firstly, the chain replacement reaction modules of emergence, activation and degradation are given through the design of DNA strand, which enable the realization of Yang chaotic system using the mass action dynamics law. Further, in order to achieve the estimation of the unknown parameters and the stability of the error system, the rules for identification of unknown parameters are derived and adaptive controllers are designed under the adaptive control principle. Finally, an internal synchronization approach is recommended to decompose the chaotic system into subsystems of different orders, which can freely choose subsystems to complete synchronization. Subsequently, numerical simulations show that DNA‐based adaptive controllers can fulfill the internal synchronization of Yang system with unknown parameters and are robust to parameter deviations. In addition, the strategy presented in this study can be extended to the synchronization control of other DSD‐based multivariable chaotic systems.