Dynamic Analysis Research Articles

Effect of High Fiber Content on Properties and Performance of CFRTP Composites

Continuously reinforced thermoplastic composites are widely used in structural applications due to their toughness, light weight, and shorter process cycle. Moreover, they provide flexibility in design and material selection. Unlike thermoset composites, continuous fiber content to maximize mechanical properties in thermoplastic composites has not been well investigated. In this paper, three thermoplastic systems are investigated to study the optimum content of continuous fiber reinforcement. These systems include carbon fiber/polyphenylene sulfide (PPS), glass fiber/PPS, and glass fiber/high-density polyethylene (HDPE). Tapes were made at several fiber contents, and samples were compression molded and tested using thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile, 3-point flexure, and short-beam shear tests. Results revealed that higher fiber content led to an increase in the glass transition and melt transition temperatures of the polymer. Some mechanical properties increased with fiber content and then began to decrease upon further addition of fibers, while other properties, such as ductility and interfacial bond strength, decreased with more reinforcement. Furthermore, the optimum fiber contents to maximize mechanical properties are different for different properties and different materials.

Backcalculation of elastic moduli of elements of layered halfspace on the basis of dynamic deformation analysis (by the example of highways)

The paper is devoted to the improvement of the method of inverse calculation of elasticity moduli of layers of motorway pavements in the dynamic setting, which involves the analysis of deformation characteristics in the time domain. To solve this problem, the mathematical model of a layered half-space is adapted to the calculation of amplitude-time characteristics of deformation on the surface of the layered medium, and the construction of the corresponding bowls of maximum values of vertical displacements. Adjustment of the calculated values of vertical displacements with respect to the registered experimental displacements in the field was performed. The correspondence between the final values of maximum vertical displacements, amplitude and time characteristics on the surface of the layered medium, and the shapes and areas of dynamic hysteresis loops on the surface of the investigated medium, achieved by adjusting the calculated characteristics relative to the experimental ones, has been demonstrated. For the first time in solving the problem of determining the mechanical parameters of a layered medium, it was proposed to consider dynamic hysteresis loops as one of the parameters characterising them and the correspondence of their calculated and experimental areas as a criterion of the adequacy of the achieved result.

Intracranial bypass for giant aneurysms treatment assessed by computational fluid dynamics (CFD) analysis

Unruptured giant intracranial aneurysms (GIA) are those with diameters of 25 mm or greater. As aneurysm size is correlated with rupture risk, GIA natural history is poor. Parent artery occlusion or trapping plus bypass revascularization should be considered to encourage intra-aneurysmal thrombosis when other treatment options are contraindicated. The mechanistic background of these methods is poorly studied. Thus, we assessed the potential of computational fluid dynamics (CFD) and fluid–structure interaction (FSI) analyses for clinical use in the preoperative stage. A CFD investigation in three patient-specific flexible models of whole arterial brain circulation was performed. A C6 ICA segment GIA model was created based on CT angiography. Two models were then constructed that simulated a virtual bypass in combination with proximal GIA occlusion, but with differing middle cerebral artery (MCA) recipient vessels for the anastomosis. FSI and CFD investigations were performed in three models to assess changes in flow pattern and haemodynamic parameters alternations (wall shear stress (WSS), oscillatory shear index (OSI), maximal time averaged WSS (TAWSS), and pressure). General flow splitting across the entire domain was affected by virtual bypass procedures, and any deficiency was partially compensated by a specific configuration of the circle of Willis. Following the implementation of bypass procedures, a reduction in haemodynamic parameters was observed within the aneurysm in both cases under analysis. In the case of the temporal MCA branch bypass, the decreases in the studied parameters were slightly greater than in the frontal MCA branch bypass. The reduction in the magnitude of the chosen area-averaged parameters (averaged over the aneurysm wall surface) was as follows: WSS 35.7%, OSI 19.0%, TAWSS 94.7%, and pressure 24.2%. FSI CFD investigation based on patient-specific anatomy models with subsequent stimulation of virtual proximal aneurysm occlusion in conjunction with bypass showed that this method creates a pro-thrombotic favourable environment whilst reducing intra-aneurysmal pressure leading to shrinking. MCA branch recipient selection for optimum haemodynamic conditions should be evaluated individually in the preoperative stage.

Symmetric structures and dynamic analysis of a (2+1)-dimensional generalized Benny-Luke equation

We study the symmetric structures and dynamic analysis of a (2 + 1)-dimensional generalized Benny-Luke (GBL) equation based on the Lie symmetry method, the GBL equation is an important non-integrable model of water waves. Specifically, we construct multiple exact solutions of the GBL equation and obtain its nonlocally related systems. Firstly, the Lie point symmetries and conservation laws of the GBL equation are computed, and then we get the reduced ordinary differential equation from one of the conservation laws. Multiple methods, for example, the dynamical systems method, the power series method, the homogeneous balancing method and generalized variable separation method, are used to solve the ordinary differential equation and abundant exact solutions of the GBL equation are got. Finally, we extend these exact solutions by discrete symmetries, and give three-dimensional graphs of partial exact solutions. In addition, we construct the nonlocally related PDE systems, which contains the potential systems from the conservation laws and an inverse system from a Lie point symmetry of the GBL equation. These findings reveal the dynamical behavior behind the GBL equation and broaden the range of nonlinear water wave model solutions.

Dynamical analysis of a switched social behavior model

Dynamical analysis of a switched social behavior model

Threshold dynamics of a degenerated diffusive incubation period host–pathogen model with saturation incidence rate

In this paper, we consider an incubation period host–pathogen system with degenerated diffusion. The global compact attractor of the solution of the model is investigated using the κ-contraction method. Furthermore, the basic reproduction number is defined, and we discuss the dynamic analysis of a degenerated diffusion model. The obtained theoretical results are nontrivial and can be considered a continuation of the work by Wang et al. in 2022.

Pursuing Extreme Descriptive Power and Generality in Chemical Bond Theories: A Method to Decipher "Interatomic Genomes" from Interatomic Electron Structures.

The description and analysis of chemical bonds have been difficult following the popularization of electronic structure calculations. Although many attempts have been made from the perspective of electronic structure, the sheer volume of information in the electronic structure has left contemporary chemical bond analysis methods grappling with an inescapable "Trilemma" where the model briefness, generality, and descriptiveness (descriptive power) cannot be obtained simultaneously. To push the generality and descriptiveness to their extremes, herein a general machine learning-based framework is introduced to compact chemical bonds into a detailed residue-by-residue "genome" with matched encoding/decoding tools. The framework fuses the quantum mechanical aspects, auto feature extraction, nanostructures and/or simulations, and generative models. The encoded genomes are information-dense and decodable, where 100% generality is guaranteed. The descriptiveness of genomes appears to be broader than most known models. As a proof of concept, the realization presented in this work compacts the complete information regarding two critical chemical bonds in thiolate-protected gold nanoclusters, the S-Au and Au-Au bonds, from a Bosonic-Fermionic character perspective into 8-valued genomes. The machine learning component is trained based on 26,528 density functional theory simulated electron localization function images. With an exploration of the space span for the genome, bond polarization, hybridization, intrusion of other atoms, alignments, crystal orientation, atomic motions, and more details are observed. Furthermore, it has emerged from extensive generation tests that molecules and solids can be integrated in such a concise manner than is typically achieved with purely geometric representations. To showcase the intraclass complexity of S-Au and Au-Au bonds visually, a roadmap is plotted by summarizing and correlating the similarities of 8-value-genomes. Furthermore, genomes can be associated with realistic indices easily with a simple multilayer perception architecture as a simple calculating tool. Besides, there are 3 sets of applications, including a set of chemisorption, a set of molecular dynamical analysis, and a set of ultrafast processes, showcasing the interpretability potentials of interatomic genomes in the geometric structures, kinetic properties, and vibration characteristics of molecular systems. As the framework rose to the challenge of nanoclusters from a complicated mesoscopic family of material, the displayed generality and comprehensiveness indicate that the model may "understand" chemical bonds in a machine's way.

Images of the auditor’s job and associated emotions: a dynamic analysis

This study aims to understand the images that undergraduates have of the job of auditor and the emotions accompanying those pictures. Auditing is a public interest profession focused on ensuring integrity and credibility of companies’ performance and position. First, we relied on personal visualizations expressed by the participants to analyze their images about the auditor’s job, and their changes. After that, we analyzed the emotions accompanying auditor job images, including positive emotions such as enjoyment and hope, and negative emotions such as anger, anxiety, and boredom. We also examined the evolution of the outcome by analyzing the emotions at two timepoints to capture changes in emotions accompanying the image of the auditor’s job after a session focused on the profession. The results reveal that most participants relied on traditional images, although the classical view decreased after the activity. The emotional perception of the job of auditor was mostly positive. The evidence also suggests less unpleasant emotions associated with a contemporary vision compared with a traditional view. Notably, unpleasant emotions decreased after auditing activity in both visions, and pleasant emotions increased. Study participants’ characteristics also delve into different profiles, considering emotions accompanying auditor job images. The current study combines a dynamic study of emotions and research on perceptions of the auditor’s job through personal images, which is an innovation and advancement in the auditing field owing to the importance of the affective side in critical thinking, behavior, and decision making. The findings of this study also emphasize the need that universities rethink the approach and information provided to students about the auditor’s job promoting collaboration between professional and academic worlds to improve not only perceptions about the profession but also the affective side.

Grid Multibutterfly Memristive Neural Network With Three Memristive Systems: Modeling, Dynamic Analysis, and Application in Police IoT

Grid Multibutterfly Memristive Neural Network With Three Memristive Systems: Modeling, Dynamic Analysis, and Application in Police IoT

The Interplay of Dietary Habits, Economic Factors, and Globalization: Assessing the Role of Institutional Quality

Background: Dietary habits are pivotal for population health and well-being, yet remain a pressing global issue, particularly in Sub-Saharan Africa (SSA), where economic instability and institutional challenges exacerbate dietary problems. Despite extensive research, there is a notable gap in the literature regarding the direct and interactive effects of institutional quality and inflationary shocks on dietary habits. Methods: This study delves into these complex interplays across 44 SSA nations from 2002 to 2022. Employing an innovative entropy method (EM) and the generalized autoregressive conditional heteroskedasticity (GARCH) modeling, the study introduces an inclusive institutional quality index and an inflationary shock predictor as crucial determinants of dietary habits in the literature. Results: The results from the panel-corrected standard error (PCSE) method and feasible generalized least squares (FGLS) model reveal that per capita GDP, school enrollment rate, government expenditures, globalization index, and urbanization are positively associated with population dietary habits, while inflationary shock, food insecurity, and unemployment rate exert negative influences. Notably, institutional quality acts as a catalyst, amplifying the positive effects of the former group and absorbing the negative impacts of the latter on population dietary habits. Additionally, a dynamic panel causality analysis confirms a bidirectional causality nexus between population dietary habits and all variables, except for inflationary shocks, which demonstrate a unidirectional causality link. Conclusions: These findings carry significant policy implications, underscoring the complex dynamics between institutional quality, inflationary shocks, and dietary habits in the region. The bidirectional causality highlights the need for holistic interventions that address economic, social, and institutional factors simultaneously. Moreover, the unidirectional causality of inflationary shocks on dietary habits suggests that stabilizing inflation is critical to protecting dietary habits. These results provide critical insights for policymakers to design targeted interventions aimed at improving nutrition, bolstering institutional frameworks, and ensuring public health resilience in the face of economic and social shocks.

Finite Element Modelling for the Dynamic Behaviour Analysis of a Structure with Hi-Lok Fasteners

The number of Hi-Lok fasteners used in the assembly of aircraft structures is very high. For this reason, an efficient modelling technique is required to accurately analyse the dynamic behaviour of the structures. In this study, a modelling technique with special emphasis on Hi-Lok modelling is proposed to analyse the dynamic behaviour of a test structure with Hi-Lok fasteners. Four different finite element (FE) models to represent the test structure with the Hi-Lok fasteners were developed using MSC Software packages. The natural frequencies and mode shapes obtained from the FE models are compared with those of the Experimental Modal Analysis (EMA) in terms of total error, computational time and memory disk usage. It was found that the model D with the simplified beams representing Hi-Lok predicts the dynamic behaviour of the test structure with an accuracy of 96.6% and with comparatively low computational time and memory disk usage. This proposed modelling scheme may provide useful approaches to aircraft researchers and engineers for the dynamic analysis of the structures.

Dynamical analysis, control, boundedness and prediction for a fractional-order financial risk system

Abstract This paper delves into the dynamical analysis, chaos control, Mittag-Leffler Boundedness (MLB) and forecasting a Fractional-Order Financial Risk (FOFR) system through an absolute function term. To this end, the FOFR system is first proposed, and the Adomian Decomposition Method (ADM) is employed to resolve this fractional-order system.The stability of equilibrium points and the corresponding control schemes are assessed, and several classical tools such as Lyapunov Exponents (LE), Bifurcation Diagrams, Complexity Analysis (CA), and 0-1 test are further extended to analyze the dynamical behaviors of FOFR. Then the global Mittag-Leffler Attractive Set (MLAS) and Mittag-Leffler Positive Invariant Set (MLPIS) for the proposed Financial Risk (FR) system are discussed. Finally, a proficient reservoir-computing (RC) method is applied to forecast the temporal evolution of the complex dynamics for the proposed system, and some simulations are carried out to show the effectiveness and feasibility of present scheme.

Stochastic Modeling and Analysis of Hepatitis and Tuberculosis Co-Infection Dynamics

Abstract Several mathematical models have been developed to investigate the dynamics of Tuberculosis (TB) and Hepatitis B Virus (HBV). Numerous current models for TB, HBV, and their co-dynamics fall short in capturing the important and practical aspect of unpredictability. It is crucial to take into account a stochastic co-infection HBV-TB epidemic model since different random elements have a substantial impact on the overall dynamics of these diseases. We provide a novel stochastic co-model for TB and HBV in this study, and we establish criteria on the uniqueness and existence of a non-negative global solution. We also looked at the persistence of the infections as long its dynamics are governable by the proposed model. To verify the theoretical conclusions, numerical simulations are presented keeping in view the associated analytical results. The infections are found to finally die out and go extinct with certainty when Lvy intensities surpass the specified thresholds and the related stochastic thresholds fall below unity. The findings also demonstrate the impact of noise on the decline in the cocirculation of HBV and TB in a given population. Our results provide insights into effective intervention strategies, ultimately aiming to improve the management and control of TB and HBV co-infections.

Synthesis and Evaluation of 18F-Labeled Phenylpiperazine-like Dopamine D3 Receptor Radioligands for Positron Emission Tomography Imaging.

The dopamine D3 receptor (D3R) is important in the pathophysiology of various neuropsychiatric disorders, such as depression, bipolar disorder, schizophrenia, drug addiction, and Parkinson's disease. Positron emission tomography (PET) with innovative radioligands provides an opportunity to assess D3R in vivo and to elucidate D3R-related disease mechanisms. Herein, we present the synthesis of eight 18F-labeled phenylpiperazine-like D3R-selective radioligands possessing good radiochemical purity (>97%), in vitro stability (>95%), and befitting lipophilicity. Based on in vitro binding assays and static microPET studies, the phenylpiperazine-like radioligands [18F]FBPC01 and [18F]FBPC03 were chosen as lead radioligands targeting D3R. Molecular docking further elucidated their binding mechanism. Radiolabeling conditions were optimized and then applied to an automated radiolabeling process, affording products with high specific activity (>112 GBq/μmol). Dynamic rat PET study demonstrated the specific binding of [18F]FBPC01 and [18F]FBPC03 to D3R in the brain ventricles and the pituitary gland. Validated by dynamic PET data analysis, biodistribution study, and metabolism analysis, [18F]FBPC03 exhibited the highest PET signal-to-noise ratio, good D3R-specific binding in the brain ventricles and pituitary gland of rats with few off-target binding, negligible defluorination, and stable brain metabolism, which indicated that [18F]FBPC03 was a promising D3R radioligand.

Structural design and dynamic analysis of a metal rubber composite gear pair

This paper introduces a metal rubber composite gear for gear vibration reduction. A comprehensive structural design calculation program is developed for the metal rubber composite gear pair. The design incorporates a gap between the tooth ring and the hub to accommodate thermal expansion and contraction, ensuring smooth transmission without jamming or seizing. The design process takes into consideration the compression and damping properties of the metal rubber material. A significant variable in the design process is the relative density of the metal rubber material. It is utilized to calculate the torsional stiffness, starting friction torque, and dynamic performance of the composite gear pair. To guide and optimize the design process, a nine-degree-of-freedom dynamic model is employed for dynamic analysis. The vibration reduction effect of the metal rubber composite gear is validated through numerical simulations and experimental testing. The results confirm the efficacy of the gear in reducing vibrations. This paper provides valuable insights and guidance for future designs focused on gear vibration reduction, paving the way for further advancements in this field.

Developing Business Strategies to Grow the Business of PT Asia Civil Indonesia

The significant market growth translate into business opportunity for construction such toll road, office building, bridge, LRT, High speed train, including huge opportunity in IKN and data centre with potential The Indonesia Construction Market size is estimated at USD 264.34 billion in 2023, and is expected to reach USD 379.41 billion by 2028, growing at a CAGR of 7.50% during the forecast period (2023-2028). This opportunity in industry up trend but no impact in growth PT Asia Civil Indonesia and company need to renew and review their focus on business model development with business strategy approach and need to evaluation they are market growth and cost structure. In qualitative research utilizing depth interviews, the research design serves as the blueprint guiding the investigation’s execution. The primary objective of this research approach is to delve deeply into participants’ thoughts, feelings, and experiences to gain rich and nuanced insights into the phenomena under study. In conclusion, the research conducted on PT ACI underscores the importance of strategic initiatives in enhancing its business operations within the construction industry. Through a comprehensive analysis of current business practices and market dynamics, PT ACI can identify areas for improvement and leverage opportunities for growth. The implementation plan outlined in the study emphasizes the significance of networking strategies and technology adaptation in achieving business objectives. Networking plays a pivotal role in expanding PT ACI’s reach within the industry, facilitating valuable connections with potential clients, partners, and industry peers. By actively participating in industry events, forums, and networking opportunities, PT ACI can build relationships, gain insights into market trends, and secure new business opportunities.

Dynamic modeling and vibration analysis for motorized spindle with uncertainties

Abstract Uncertainties inevitably exist in motorized spindle and it is difficult to accurately describe its dynamics based on a deterministic model. In this paper, a dynamic model of motorized spindle with uncertainty is proposed. The deterministic dynamic model of the motorized spindle rotor system is built by the finite element method, and the uncertainties are constructed by the polynomial chaotic expansion (PCE) method. The impact of each uncertainty parameter on the critical speed of the system is investigated by adopting the Sobol global sensitivity analysis method. The effects of uncertainties including the bearing stiffness, the material Young’s modulus, the disc mass and the unbalanced excitation on the vibration response of motorized spindle are analyzed. The modal experiments are carried out to verify the effectiveness of the model. The results show that the uncertainties have a great influence on the vibration characteristics of the motorized spindle system, in which the bearing stiffness mainly affects the high-order frequency response of the system, while the Young’s modulus affects all the order frequency response of the system. The influence of hybrid uncertainties on the frequency response of the system is more complex. This study provides a guidance to the design of motorized spindle.

Integrated battery thermal management and CO2 control in electric buses using recirculated air and waste heat recovery

In recent years, electric vehicles (EVs) have significantly progressed due to their environmental protection and energy-saving advantages. However, maintaining indoor thermal comfort and effective battery thermal management are critical considerations for EVs. Unlike conventional vehicles, EVs cannot use waste heat and depend on heat pump systems for winter heating and summer cooling. This research proposes a novel system to reduce the energy consumption of heat pump systems by using recirculated air while addressing the challenges of battery temperature management and maintaining safe CO2 concentrations in the cabin. The primary objectives of this research are threefold: first, to ensure passenger comfort through an integrated approach that includes cabin CO2 concentration safety; second, to recover heat from recirculated cabin air to save energy and control battery temperature; and third, to comprehensively analyze the performance of the Electric Vehicle Thermal Management System (EVTMS) using precise Computational Fluid Dynamics (CFD) analysis and mathematical modeling. This study will significantly enhance the understanding of energy consumption related to CO2 concentration control; an aspect previously overlooked in the literature. It will develop a battery temperature management strategy that leverages bus exhaust heat. These contributions will aid in achieving both passenger comfort and battery stability in electric buses, providing practical insights for the design and optimization of thermal management systems for future electric buses.

Dynamic intelligent analysis of single-column pier bridges considering vehicle-bridge interaction

Dynamic intelligent analysis of single-column pier bridges considering vehicle-bridge interaction

Gait assessment in a female rat Sprague Dawley model of disc-associated low back pain

ABSTRACT Purpose Gait disturbances are common in human low back pain (LBP) patients, suggesting potential applicability to rodent LBP models. This study aims to assess the influence of disc-associated LBP on gait in female Sprague Dawley rats and explore the utility of the open-source Gait Analysis Instrumentation and Technology Optimized for Rodents (GAITOR) suite as a potential alternative tool for spontaneous pain assessment in a previously established LBP model. Materials and Methods Disc degeneration was surgically induced using a one-level disc scrape injury method, and microcomputed tomography was used to assess disc volume loss. After disc injury, axial hypersensitivity was evaluated using the grip strength assay, and an open field test was used to detect spontaneous pain-like behavior. Results Results demonstrated that injured animals exhibit a significant loss in disc volume and reduced grip strength. Open field test did not detect significant differences in distance traveled between sham and injured animals. Concurrently, animals with injured discs did not display significant gait abnormalities in stance time imbalance, temporal symmetry, spatial symmetry, step width, stride length, and duty factor compared to sham. However, comparisons with reference values of normal gait reported in prior literature reveal that injured animals exhibit mild deviations in forelimb and hindlimb stance time imbalance, forelimb temporal symmetry, and hindlimb spatial symmetry at some time points. Conclusions This study concludes that the disc injury may have very mild effects on gait in female rats within 9 weeks post-injury and recommends future in depth dynamic gait analysis and longer studies beyond 9 weeks to potentially detect gait.