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The purpose of this paper is to introduce a local Newton basis functions collocation method for solving the 2D nonlinear coupled Burgers’ equations. It needs less computer storage and flops than the usual global radial basis functions collocation method and also stabilizes the numerical solutions of the convection-dominated equations by using the Newton basis functions.

A meshless method based on spatial trial space spanned by the local Newton basis functions in the “native” Hilbert space of the reproducing kernel is presented. With the selected local sub-clusters of domain nodes, an approximation function is introduced as a sum of weighted local Newton basis functions. Then the collocation approach is used to determine weights. The method leads to a system of ordinary differential equations (ODEs) for the time-dependent partial differential equations (PDEs).

The method is successfully used for solving the 2D nonlinear coupled Burgers’ equations for reasonably high values of Reynolds number (Re). It is a well-known issue in the analysis of the convection-diffusion problems that the solution becomes oscillatory when the problem becomes convection-dominated if the standard methods are followed without special treatments. In the proposed method, the authors do not detect any instability near the front, hence no technique is needed. The numerical results show that the proposed method is efficient, accurate and stable for flow with reasonably high values of Re.

The authors used more stable basis functions than the standard basis of translated kernels for representing of kernel-based approximants for the numerical solution of partial differential equations (PDEs). The local character of the method, having a well-structured implementation including enforcing the Dirichlet and Neuman boundary conditions, and producing accurate and stable results for flow with reasonably high values of Re for the numerical solution of the 2D nonlinear coupled Burgers’ equations without any special technique are the main values of the paper.

This paper examines several modifications to Newton's method for the numerical solution of the nonlinear Poisson equation which describes the electrostatic potential distribution in a semiconductor device. Two methods for a more efficient solution of the equation when the device is a Metal‐Oxide‐Semiconductor Field Effect Transistor are proposed. Their extension to the solution of the fully coupled system of equations is also discussed. The modifications to Newton's method are also compared numerically.

The purpose of this paper is to focus on the performance of three typical nonlinear least-squares estimation algorithms in atmospheric density model calibration.

The error of Jacchia-Roberts atmospheric density model is expressed as an objective function about temperature parameters. The estimation of parameter corrections is a typical nonlinear least-squares problem. Three algorithms for nonlinear least-squares problems, Gauss–Newton (G-N), damped Gauss–Newton (damped G-N) and Levenberg–Marquardt (L-M) algorithms, are adopted to estimate temperature parameter corrections of Jacchia-Roberts for model calibration.

The results show that G-N algorithm is not convergent at some sampling points. The main reason is the nonlinear relationship between Jacchia-Roberts and its temperature parameters. Damped G-N and L-M algorithms are both convergent at all sampling points. G-N, damped G-N and L-M algorithms reduce the root mean square error of Jacchia-Roberts from 20.4% to 9.3%, 9.4% and 9.4%, respectively. The average iterations of G-N, damped G-N and L-M algorithms are 3.0, 2.8 and 2.9, respectively.

This study is expected to provide a guidance for the selection of nonlinear least-squares estimation methods in atmospheric density model calibration.

The study analyses the performance of three typical nonlinear least-squares estimation methods in the calibration of atmospheric density model. The non-convergent phenomenon of G-N algorithm is discovered and explained. Damped G-N and L-M algorithms are more suitable for the nonlinear least-squares problems in model calibration than G-N algorithm and the first two algorithms have slightly fewer iterations.

Alcohol and cannabis are the two most commonly used substances by young people in many developed nations. The purpose of this paper is to explore the longitudinal relationships between risky substance use (binge drinking and cannabis use) and psychological distress, emotional and behavioural difficulties, and truancy among Australian adolescents.

A total of 527 students (Mage=13.4 years, SD=0.43; 67 per cent female) from seven Australian schools completed an online self-report survey on four occasions over two years (baseline, 6, 12 and 24 months). The survey assessed binge drinking (5+ standard drinks on one occasion), cannabis use in the past six months, psychological distress, emotional and behavioural difficulties (Strength and Difficulties Questionnaire), and truancy. Generalised estimating equations (GEEs) were conducted to examine the longitudinal relationship between the substance use outcomes and each predictor variable.

At baseline, 3 per cent of students reported binge drinking and 6 per cent had used cannabis in the past six months. Rates of binge drinking significantly increased over time (21.1 per cent at 24 months) however, rates of cannabis use remained relatively stable (8.8 per cent at 24 months). Multivariate GEE analyses indicated that higher levels of hyperactivity/inattention, more days of truancy and being female were independently and consistently associated with binge drinking over time. Conduct problems was the only factor to be independently associated with cannabis use over time.

These findings provide valuable information about psychosocial risk factors for harmful alcohol and cannabis use. A better understanding of these associations is critical for informing substance use prevention efforts in the future.

The purpose of this paper is to explore how different trajectories of emotional symptoms relate to alcohol use in adolescence.

In all, 431 participants (majority female), aged approximately 13 years at baseline were followed over three years and reported on their emotional symptoms and alcohol use. Latent class growth analyses explored different trajectories of emotional symptoms and regression models were run to relate these trajectories to alcohol use (full standard drink, and binge drinking) at 36-month follow-up (age 16 years).

While the majority of adolescents were best characterised by low-stable emotional symptoms, those with high-stable symptoms were more likely to be have consumed a full standard drink of alcohol and binge drunk when aged 16 years.

Findings highlight the importance of prevention and early intervention, particularly targeting adolescents with elevated stable emotional symptoms who were more likely to be using alcohol at 16 years of age.

The present study is one of the first longitudinal investigations into the use of alcohol by community adolescents with different emotional symptom trajectories.

While concern for the quality of working life (QWL) is by no means new it is nevertheless true that there has been an enormous amount of research, experimentation and commentary in this field in recent years. A particular confluence of forces—ever‐accelerating technological change; rapidly‐shifting attitudes, life‐styles, and social institutions; and the paradox in many countries of a customary prosperity threatened by doubts as to future economic performance—is at least in part responsible for the burgeoning interest in the field. But important also is its multidisciplinary nature, which has afforded to social scientists of varied orientations the opportunity to participate in a new intellectual growth industry.

The purpose of this paper is to examine the effects of political connections surrounding an exogenous Supreme Court decision (Citizens United) that lifted long-standing restrictions on corporate political contributions.

This study examines key characteristics of politically connected firms compared to non-politically connected firms, including their market reaction to Citizens United, as well as cash holdings levels and governance characteristics before vs after the landmark decision.

The results indicate a significant negative market reaction to politically connected firms surrounding the announcement of Citizens United. Additionally, there is a significant increase in the cash holdings of politically connected firms relative to before the event and relative to non-politically connected firms. For politically connected firms, this result is exacerbated by poor corporate governance quality. Collectively, these findings are consistent with a positive association between agency costs and political connections.

This study provides novel evidence by exploiting an exogenous enhancement in the implications of political connections that accompanied the Citizens United decision. The use of this quasi-natural experiment offers an ideal research setting to extract fresh insights into the effects of corporate political connections.

To set up the analytical model of reaction wheel assembly (RWA) by using the other theory and to provide a new method to identify the parameters of the empirical model of RWA.

Setting up the analytical model of RWA using virtual work theory, and presents the energy compensation method. The energy compensation method to improve the computation accuracy of amplitude coefficients of the empirical model of RWA. In the empirical model of RWA, the assumption is that the disturbances consist of discrete harmonics, and the amplitudes is proportion to the square of the wheel speed.

The errors of amplitude coefficients adopting energy compensation window excel the amplitude spectrum method. The energy compensation method improves the parameters identification accuracy, and provides a new method to set up more accurate empirical disturbance model of RWA.

Providing a valuable identification method of amplitude coefficients of the empirical model of RWA, and improving the accuracy of identification.

Putting forward up the method of energy compensation to identify the amplitude coefficients of the empirical model of RWA, and improving the accuracy. This method is simple, practical for the system design.

The purpose of this paper is to comprehensively review most of the significant works ever done worldwide to study the effects of essential parameters on pulsed plasma thruster (PPT) performance and to analyze the effects of each parameter on PPT performance.

All the important works studying PPT performance are categorized by the parameter they have studied and its effect on the thruster performance, and their works have been reviewed to analyze the influence of each parameter.

The analysis leads to elucidation of the effects of different geometrical parameters including aspect ratio, electrode width, electrode spacing, electrode shape, electrode length, and flare angle, in addition to the effects of other parameters such as electrode material, propellant type, propellant temperature, spark distance from propellant, pulse repetition frequency, discharge energy, capacitance, and hood angle on PPT performance.

The analysis is mainly focused on parallel‐rail breech‐fed PPTs and side‐fed PPTs and does not deal with co‐axial PPTs.

The paper reviews and analyses many of the considerable works ever done to contribute to clarify the effects of different parameters on PPT performance. The results of the current analysis can be of invaluable assistance in PPT design and optimization procedure and help the designer to develop a system with better performance characteristics.

The purpose of this paper is to investigate the effect of power on pulsed plasma thruster (PPT) discharge current with respect to its peak, duration, and behavior while the power elevates in a low power range.

A rectangular parallel‐plate breech‐fed PPT has been developed with a self‐inductor coupling element connecting the PPT cathode to the ignitor plug cathode. The PPT has been operated in vacuum chamber at 10⁻⁶ mbar and its discharge current has been recorded using a Rogowski coil while input power has been changed by means of varying the capacitor voltage at given capacitance and frequency.

The analysis leads to elucidate the effects of input power on discharge current of a PPT employing a self‐inductor coupling element. The power varies within a range of less than 10 to more than 50 W. The results show that current peak rises from 5 to 10 kA while discharge duration and behavior seems to be independent of power within the operating range. Additionally, utilization of the coupling element seems to change the typical oscillating behavior of PPT discharge to a more efficient behavior.

The analysis is mainly focused on breech‐fed PPTs while employing a coupling element.

The paper analyzes the influence of power on discharge current of a PPT employing a self‐inductor coupling element. It clarifies the behavior of current peak, duration and behavior while power varies in a low power range. The effect of coupling element is shown to be promising. The results can be a help in design of μPPTs.