Impulsive Effects Research Articles

Transmission of monetary policy impulses on the capital structure of manufacturing firms: Evidence from an emerging economy

A country's monetary policy influences a firm's economic decisions by influencing the cost of external debt offered to firms by commercial banks. However, research on the effect of monetary policy on the capital structure of firms located in bank credit-driven developing economies is limited. This research paper tries to fill that gap by examining the effects of monetary policy impulses on the short- and long-term capital structure of firms in an emerging economy. Using quadratic econometric equation and GMM regression model study analyzes annual financial data of 2575 non-financial firms belonging to 8 manufacturing sectors covering the duration of 13 years ranging from 2009 to 2021. The results show a curvilinear relationship between monetary policy impulses and firms' capital structure in different manufacturing industry sectors. Monetary policy was found to have a different impact on short-term and long-term borrowings of financially flexible and inflexible manufacturing firms.

A four-factor model of executive function: Predicting physical and academic outcomes from cognitive assessments in adolescents

Impulsivity and cognitive function are essential for understanding behavioral regulation, particularly in relation to health-risk behaviors like substance use, physical activity, and academic performance. This study examined the factor structure underlying executive function in adolescents using the UPPS-P Impulsive Behavior Scale and NIH Toolbox Cognition Battery. We explored how parental monitoring moderates, and peer network health and perceived stress mediate, relationships between cognitive function and outcomes such as BMI, physical activity, and academic performance. Exploratory factor analysis (EFA) on 2228 observations identified a four-factor model (BIC = −97.92, RMSEA = 0.040, TLI = 0.936), validated by confirmatory factor analysis (CFA) (CFI = 0.961, RMSEA = 0.055). Structural equation modeling (SEM) on 5902 observations showed that parental monitoring moderated Factor 1 (adaptive impulsivity) in relation to physical activity and academic performance, while peer network health mediated Factor 2 (emotional impulsivity) effects on BMI and physical activity. This model underscores the influence of peer relationships, parental involvement, and stress on cognitive, health, and academic outcomes, suggesting that interventions enhancing peer support, reducing stress, and promoting healthy behaviors may improve adolescent well-being.

Second-order strongly nonlinear impulsive coupled systems

This paper presents sufficient conditions for the solvability of a second-order coupled system, composed of two differential equations involving different laplacians applied to fully discontinuous nonlinearities, two-point boundary conditions, and generalized impulsive effects. Applying the lower and upper solutions technique and Schauder’s fixed point theorem, it is obtained an existence and localization theorem, based on local monotone properties on the nonlinearities and the impulsive functions.

A Study on the Evolution Laws of Entrainment Performances Using Different Mixer Structures of Ejectors.

Being the core of the ejector refrigeration system, an ejector with a suitable mixer, conical-cylindrical or cylindrical, is key to high-energy-efficiency and low-carbon systems. To promote the scientific selection of mixers for ejectors based on the theoretical models that have been validated by experiments, the evolution laws of the entrainment ratios in the two types of ejectors are studied under various operating conditions. Furthermore, the influence mechanism of the mixer structures on the entrainment ratio of the ejector is elucidated by comparing the distribution characteristics of the entropy generation rate, pressure lift proportion, and entropy generation rate of the per-unit pressure lift in the two types of ejectors. The efficiencies of the conical-cylindrical mixer ejector and cylindrical mixer ejector exist a crossover, which makes the entrainment ratio of the conical-cylindrical mixer ejector smaller under small compression ratios but larger under large compression ratios. By changing the cylindrical mixer into a conical one, on the one hand, more pressure rise will be distributed in the diffuser, which helps to reduce the entropy increase rate in the pressurization process; on the other hand, the wall impulse effect of the conical mixer will lead to an increase in entropy generation rate of per-unit pressure lift, resulting in a growing entropy generation rate of boosting. The dominant roles are not the same with changing compression ratios, which leads to different relationships of entrainment ratio between the cylindrical and conical mixer ejectors.

Small-scale BLEVE: Near-field aerial shock overpressure and impulse

This paper presents an investigation into one of the most damaging hazards associated with Boiling Liquid Expanding Vapor Explosion (BLEVE), specifically focusing on the near-field overpressure and impulse effects. Experiments were conducted at a small-scale to study the overpressure and impulse using aluminum tubes with a diameter of 50 mm and a length of 300 mm. The tubes were filled with pure propane liquid and vapor. The controlled variables, in this work included the failure pressure, the liquid fill level, and the weakened length along the tube top. These variables control the strength of the overpressure characterized by the peak overpressure amplitude, duration of this overpressure event, and the resultant impulse. Notably, these experiments at a small scale included experiments with a 100 % liquid fill level. This further confirmed that the vapor space is the main driver of the lead overpressure hazard. High-speed cameras and blast gauges effectively illustrated the progressive formation of the shock wave in both temporal and spatial dimensions. Furthermore, various predictive models available in the literature are discussed in this paper and new correlations were developed to quantify the overpressure duration and impulse. The current analysis aims to predict the potential consequences of overpressure events during a BLEVE.

Thermal response of TBC systems subjected to non-uniform thermal shocks and periodic thermal load: Effect of Biot number and interface imperfection

This study analytically examines the temperature variations within thermal barrier coating (TBC) systems under diverse kinds of thermal loadings, such as concentrated/distributed convective thermal shocks and oscillating thermal loads. In this study, the TBC system comprises ceramic top coat (TC) and NiCrAlY alloy bond coat (BC). The transient behavior of the TBC system facing various kinds of non-uniform convective thermal shocks is elaborated via the dual-phase-lag (DPL) heat conduction model. The effect of imperfect bonding of the TC/BC interface on transient responses of the regions in the neighborhood of the TC/BC interface is studied by considering impermeable, partially permeable and completely permeable heat flux flows. Laplace and Fourier integral transforms are employed to derive the exact solutions of time-dependent temperature fields governing equations. The prominent effects of sudden thermal impulse and steady alternating thermal loading on the variations of temperature within the TC, BC and substrate are inspected. The analysis reveals that the kind of thermal load, loading parameters, thermal properties and thickness of ceramic TC directly affect the transient/periodic temperature fields inside the TBC constituents. Meanwhile, the interface imperfection and the Biot number of convective thermal load play an impressive role in the severity of thermal response of the TBC constituents.

On the effects of impulsivity and compulsivity on neural correlates of model-based performance

Impaired goal-directed behavior is associated with a range of mental disorders, implicating underlying transdiagnostic factors. While compulsivity has been linked to reduced model-based (MB) control, impulsivity has rarely been studied in the context of reinforcement learning despite its links to reward processing and cognitive control. This study investigated the neural mechanisms underlying MB control and the influence of impulsivity and compulsivity, using EEG data from 238 individuals during a two-step decision making task. Single-trial analyses revealed a modulation of the feedback-related negativity (FRN), where amplitudes were higher after common transitions and positive reward prediction error (RPE), indicating a valence effect. Meanwhile, enhanced P3 amplitudes after rare transitions and both positive and negative RPE possibly reflect surprise. In a second step, we regressed the mean b values of the effect of RPE on the EEG signals onto self-reported impulsivity and compulsivity and behavioral MB control (w). The effect of RPE on FRN-related activity was mainly associated with higher w scores, linking the FRN to MB control. Crucially, the modulation of the P3 by RPE was negatively associated with compulsivity, pointing to a deficient mental model in highly compulsive individuals.

Longitudinal examination of marijuana use and physical teen dating violence: Antisocial peers and impulsivity as mediators

BackgroundPrior studies have shown that marijuana use is often associated with physical teen dating violence. However, few studies have examined the longitudinal mediating effects of associating with antisocial peers and impulsivity on this relationship. Also, few studies have estimated the cascading developmental impact of marijuana use and antisocial peer association, predicting the continued marijuana use and antisocial peer associations while considering the risk of impulsivity in physical teen dating violence. Thus, the current study utilized the problem behavior theory and an alternative path to physical dating violence to address these limitations. ObjectiveThe current study tested the longitudinal effects of marijuana use on physical teen dating violence and the indirect effects of antisocial peer association and impulsivity on this relationship (M = 12.29); 52.1 % of males and 47.9 % of females participated. MethodsAdolescents completed questionnaires at baseline and were assessed six months later (n = 836). Generalized structural equation modeling (GSEM) and cross-lagged mediation models were used first to analyze the direct effect of lifetime marijuana use on physical dating violence and antisocial peer association and impulsivity as potential mediators of this relationship. Then, the cross-lagged mediation models were used to estimate the alternative path to physical teen dating violence using lifetime marijuana use and antisocial peer association as predictors at baseline and continued antisocial peer association, marijuana use, and impulsivity at the subsequent wave as mediators. ResultsResults suggested that marijuana use at baseline was not positively associated with physical teen dating violence over time. The association with antisocial peers but not impulsivity mediated the relationship between marijuana use and physical dating violence. Cross-lagged mediation results suggested that marijuana use at baseline positively predicted antisocial peer association in the subsequent wave, which led to an increase in physical teen dating violence. Further, antisocial peer association at baseline is positively associated with continued antisocial peer association at the subsequent wave; thus, antisocial peer association is positively related to physical teen dating violence when controlling for depressive symptoms, family support, number of dates, and parental monitoring. ConclusionThese results suggest though marijuana use alone is not statistically associated with physical teen dating violence, it does increase the risk of antisocial social peer associations that could increase adolescents' likelihood to engage in physical teen dating violence. Further, the onset of antisocial peer association could persist over time, thus serving as a risk factor for physical teen dating violence over time.

Delay-compensatory synchronization on uncertain chaotic neural networks via average delayed impulsive gains

This paper mainly studies the exponential synchronization issue of chaotic neural networks with parametric uncertainties and time-varying delays via hybrid impulsive control and delay compensatory strategy. Considering the hybrid impulses and flexible delays in the controller, the idea of average delayed impulsive gain (ADIG) is introduced to quantify the effects of hybrid impulses from a comprehensive viewpoint, i.e., not only the desynchronizing/synchronizing delay-free impulses but also the desynchronizing/synchronizing delayed impulses are discussed. Meanwhile, the impulsive delays are fetched and integrated to compensate the desynchronizing impulses dynamically, which removes certain strict restrictions on the impulsive gains and impulsive delays compared with existed works. Correspondingly, some relaxed sufficient criteria for exponential synchronization are derived by jointly utilizing the concept of average delayed impulsive gain, the delay compensatory scheme and the mathematical induction methodology. Ultimately, two examples with some comparisons are given to verify the applicability and superior performance of the obtained results.

Study on unseating prevention for multi-union long simply supported girder bridges under near-fault ground motions

Girder shifting is a common form of seismic damage for girder bridges. Unseating could occur when the displacement of the girder is too large, especially for bridges near faults, because the velocity impulse effect leads to greater displacement responses of structures. Setting metal dampers between girders and piers is a useful way to control the seismic behavior and reduce the risk of unseating. Since metal dampers are inevitably exposed to the erosive service environments, their mechanical properties may degrade due to corrosion. In this paper, a U-shaped metal damper made of stainless steel instead of mild steel (i.e., U-shaped stainless steel damper, which could be named simply as USSSD) is proposed and applied to the seismic reduction design of girder bridges. First, the finite element model (FEM) of the USSSD is built by the ABAQUS, and its force-displacement relationship is obtained based on the skeleton curve, which is fitted by the trilinear kinematic strengthening model. Then, a multi-union long simply supported girder bridge is taken as an example. The FEM of the adopted bridge is established via the Midas Civil to verify the seismic mitigation effect of the proposed USSSD excited by near-fault ground motions. The numerical analyses demonstrate that the unseating may occur without the use of the USSSDs. The relative displacement between the girder and pier is effectively controlled by the USSSDs, and the reduction is more than 50 %. When the bridge is equipped with the USSSDs, both the curvature ductility coefficient of the pier bottom and the maximum drift of the pier tip increase by a limited amplitude, which do not cause additional damage to the piers.

Existenceof Heteroclinic Solutions in Nonlinear Differential Equations of the Second-Order Incorporating Generalized Impulse Effects with the Possibility of Application to Bird Population Growth

This work considers the existence of solutions of the heteroclinic type in nonlinear second-order differential equations with ϕ-Laplacians, incorporating generalized impulsive conditions on the real line. For the construction of the results, it was only imposed that ϕ be a homeomorphism, using Schauder’s fixed-point theorem, coupled with concepts of L1-Carathéodory sequences and functions along with impulsive points equiconvergence and equiconvergence at infinity. Finally, a practical part illustrates the main theorem and a possible application to bird population growth.

Fractional Differential Equations with Impulsive Effects

This paper discusses impulsive effects on fractional differential equations. Two approaches are taken to obtain our results: either with fixed or changing lower limits in Caputo fractional derivatives. First, we derive an existence result for periodic solutions of fractional differential equations with periodically changing lower limits. Then, the impulsive effects are modeled for fractional differential equations regarding the nonlinearities rather than the initial value conditions. The proposed impulsive model differs from common discontinuous and nonsmooth dynamical systems.

The Effect of Social Support on Aggression Among Male Juvenile Delinquents in China: The Multiple Mediated Role of Trait Mindfulness and Self-Control/impulsivity

ABSTRACT Objectives To examine the relationship between social support and aggression among male juvenile delinquents and the mediating role of mindfulness and self-control/impulsivity. Methods A total of 530 male juvenile delinquents completed the Social Support Rating Scale, the Mindful Attention Awareness Scale, the Self-Control Scale, the Aggression Questionnaire, and the Barratt Impulsiveness Scale. Results The total effect of social support on aggression was significant (β= −0.24, p < 0.001, Bootstrap 95%CI[−0.38, −0.19]). Social support affected individual aggression through the following five paths: (1) social support → trait mindfulness → aggression (Bootstrap 95%CI[−0.07, −0.01]); (2) social support → self-control → aggression (Bootstrap 95%CI[−0.18, −0.08]); (3) social support →impulsivity → aggression (Bootstrap 95%CI[−0.12, −0.05]); (4) social support → trait mindfulness → self-control → aggression (Bootstrap 95%CI[−0.07, −0.01]); (5) social support → trait mindfulness →impulsivity → aggression (Bootstrap 95%CI[−0.03, −0.01]), indicating that these five mediating effects were significant. Conclusions It suggests that social support is associated with aggression among male juvenile delinquents. Social support is negatively correlated with aggression through multiple mediating effects of mindfulness, self-control, and impulsivity.

A novel fault diagnosis method for bearing based on maximum average kurtosis morphological deconvolution

Abstract Maximum average kurtosis deconvolution (MAKD) effectively enhances periodic impulses in vibration signals. However, under conditions of random impulse interference, MAKD tends to amplify impulses within a single period. To address this problem, this paper proposes a maximum average kurtosis morphological deconvolution (MAKMD) method. First, on the basis of proposing a time-varying structural element more in line with the characteristics of vibration signals and constructing a new morphological gradient squared operator, an enhanced time varying morphological filtering (ETVMF) is proposed. Then, ETVMF is introduced into MAKD to eliminate the effect of random impulse. Finally, the diagonal slice spectrum (DSS) is utilized to detect the coupling frequency of the bearing, which makes the spectrum clearer and more convenient for bearing fault diagnosis. In MAKMD, the effect of random impulse is eliminated and the capability of fault feature extraction is enhanced. To demonstrate the method’s effectiveness and feasibility, experiments are conducted using simulated signals and measured bearing fault data, comparing results with existing deconvolution methods.

Finite-time cluster synchronization of multi-weighted fractional-order coupled neural networks with and without impulsive effects

In this paper, finite-time cluster synchronization (FTCS) of multi-weighted fractional-order neural networks is studied. Firstly, a FTCS criterion of the considered neural networks is obtained by designing a new delayed state feedback controller. Secondly, a FTCS criterion for the considered neural networks with mixed impulsive effects is given by constructing a new piecewise controller, where both synchronizing and desynchronizing impulses are taken into account. It should be noted that it is the first time that finite-time cluster synchronization of multi-weighted neural networks has been investigated. Finally, numerical simulations are given to show the validity of the theoretical results.

Exponential synchronization of stochastic coupled neural networks with stochastic delayed impulsive effect

This paper studies the synchronization of stochastic coupled neural networks (SCNNs) with stochastic delayed impulses, which are more realistic and complex than the deterministic ones. Unlike previous works, we incorporate two distinct types of stochastic factors into the model: random noise affecting the systems continuous dynamics, and stochastic impulsive intensity applied at discrete impulsive instances. We extend the differential inequality with stochastic delayed impulses to stochastic systems without requiring that impulsive delay to be smaller than impulsive interval. We also model the impulsive intensity as a discrete-time Markov chain. By using the generalized inequality, graph theory, and stochastic analysis techniques, we derive a synchronization criterion for SCNNs with stochastic delayed impulses. We present numerical examples to demonstrate the effectiveness of our results.

Fixed-time stability analysis of general impulsive systems and application to synchronization of complex networks with hybrid impulses

In this paper, the fixed-time stability of general impulsive systems and the fixed-time synchronization issue of impulsive complex networks are investigated. First, the fixed-time stability of a class of nonlinear systems with general impulsive effects is analyzed by means of inequality method and using some special functions. Then, the developed fixed-time stability results are used to study the fixed-time synchronization of impulsive complex networks under the saturation controller. Compared with some early published works, in this paper, the estimation accuracy of settling time is improved by calculating the value of improper integral more precisely, and the saturation controller effectively suppresses chattering phenomenon caused by discontinuous signum function. Lastly, some numerical examples are given to verify the feasibility of our theoretical results.

Delay dependent complex-valued bidirectional associative memory neural networks with stochastic and impulsive effects: an exponential stability approach

Delay dependent complex-valued bidirectional associative memory neural networks with stochastic and impulsive effects: an exponential stability approach

An impulsive geomagnetic effect from an early-impulsive flare

ABSTRACT The geomagnetic ‘solar flare effect’ (SFE) results from excess ionization in the Earth’s ionosphere, famously first detected at the time of the Carrington flare in 1859. This indirect detection of a flare constituted one of the first cases of ‘multimessenger astronomy’, whereby solar ionizing radiation stimulates ionospheric currents. Well-observed SFEs have few-minute time-scales and perturbations of &amp;gt;10 nT, with the greatest events reaching above 100 nT. In previously reported cases, the SFE time profiles tend to resemble those of solar soft X-ray emission, which ionizes the D-region; there is also a less-well-studied contribution from Lyman α. We report here a specific case, from flare SOL2024-03-10 (M7.4), in which an impulsive SFE deviated from this pattern. This flare contained an ‘early impulsive’ component of exceptionally hard radiation, extending up to γ-ray energies above 1 MeV, distinctly before the bulk of the flare soft X-ray emission. We can characterize the spectral distribution of this early-impulsive component in detail, thanks to the modern extensive wavelength coverage. A more typical gradual SFE occurred during the flare’s main phase. We suggest that events of this type warrant exploration of the solar physics in the ‘impulse response’ limit of very short time-scales.

New fixed-time/preassigned-time stability results of impulsive systems and its application to synchronization of delayed octonion-valued neural networks

In this paper, in order to obtain more accurate settling time estimation and overcome the complexity of the theoretical analysis caused by using decomposition method, the problem of fixed-time (F-T) and preassigned-time (P-T) synchronization of delayed octonion-valued neural networks with impulsive effects is explored by utilizing direct octonion approach. First, a new fixed-time stability theorem for impulsive system is presented by using the comparison principle, average impulsive interval and Bernoulli differential equation theory. Second, to solve the problems of non associative and non commutative laws of octonion, some novel lemmas are introduced, which are the basis of the direct octonion approach. Third, under the improved F-T stability result, a new P-T stability theorem is derived and the settling time is preassigned according to realistic need and is irrelevant with any initial values and any parameters. Then, based on newly established theorems and developed controller strategies, some sufficient conditions are deduced to guarantee F-T and P-T synchronization of the discussed systems. Finally, a numerical simulation is provided to verify the effectiveness of the theoretical results.