Analytical approach to the transition to thermal hopping in the thin- and thick-wall approximations

The nature of the transition from the quantum tunneling regime at low temperatures to the thermal hopping regime at high temperatures is investigated analytically in scalar field theory. An analytical bounce solution is presented, which reproduces the action in the thin-wall as well as thick-wall limits. The transition is first order for the case of a thin wall while for the thick wall case it is second order.Comment: Latex file, 22 pages, 4 Postscript figure

Topological Defects in the Left-Right Symmetric Model and their Relevance to Cosmology

It is shown that the minimal left-right symmetric model admits cosmic string and domain wall solutions. The cosmic strings arise when the SU(2)_R is broken and can either be destabilized at the electroweak scale or remain stable through the subsequent breakdown to U(1)_{EM}. The strings carry zero modes of the neutrino fields. Two distinct domain wall configurations exist above the electroweak phase transition and disappear after that. Thier destablization provides new sources of non-equilibrium effects below the electroweak scale which is relevant to baryogenesis.Comment: 29 pages, LaTex file with 6 postscript figure

Bubble formation in ϕ6\phi^6 potential

Scalar field theory with an asymmetric potential is studied at zero temperature and high-temperature for $\phi^6$ potential. The equations of motion are solved numerically to obtain O(4) spherical symmetric and O(3) cylindrical symmetric bounce solutions. These solutions control the rates for tunneling from the false vacuum to the true vacuum by bubble formation. The range of validity of the thin-wall approximation (TWA) is investigated. An analytical solution for the bounce is presented, which reproduces the action in the thin-wall as well as the thick-wall limits.Comment: 22 pag

Controlling Chaos and Bifurcation of Subsynchronous Resonance in Power System

Linear and nonlinear state feedback controllers are proposed to control the bifurcation of a new phenomenon in power system, this phenomenon of electro-mechanical interaction between the series resonant circuits and torsional mechanical frequencies of the turbine generator sections, which known as Subsynchronous Resonance (SSR). The first system of the IEEE second benchmark model is considered. The dynamics of the two axes damper windings, Automatic Voltage Regulator (AVR) and Power System Stabilizer (PSS) are included. The linear controller gives better initial disturbance response than that of the nonlinear, but in a small narrow region of compensation factors. The nonlinear controller not only can be easily implemented, but also it stabilizes the operating point for all values of the bifurcation parameter

Bounce solutions and the transition to thermal hopping in phi^4 theory with a phi^3 term

The nature of the transition from quantum tunneling at low temperatures to thermal hopping at high temperatures is investigated in a scalar field theory with cubic symmetry breaking. The bounce solution which interpolates between the zero-temperature and high-temperature solutions is obtained numerically, using a multigrid method. It is found that, for a small value of the symmetry-breaking coupling f, the transition is first-order. For higher values of f, the transition continues to be first-order, though weakly so.Comment: Latex file with 18 figures, 29 page

A bottleneck investigation at escalator entry at the Brisbane central train station

© 2016 ATRF, Commonwealth of Australia. All rights reserved. Escalators are an essential for passenger’s movements through multi-level rail station concourse environments. Despite the access benefits that escalators provide, they can make travel time longer and pose some challenges when bottlenecks appear at entry. Studying the passenger behaviour of bottlenecks at escalator entrances is essential for planning, designing and control of engineering transportation systems. In this paper we investigate passenger route choice behaviour while approaching an escalator-stair infrastructure set at Brisbane Central train station. A model of an escalator entry bottleneck is formulated. The developed model can explain the queuing characteristics of the bottlenecks and can be readily used to predict congested state occurrence at escalator entry bottleneck. Accurate prediction of bottlenecks occurring around escalators and the estimation of escalator capacity are obtained based on real field data collected from Brisbane Central train station. Results have provided significant insights and computational tools for understanding many features of escalator bottlenecks. Remarkably, escalator capacity at bottleneck points affects the duration and severity of the congested period

Pengaruh Pola Asuh Orang Tua Terhadap Sikap Tanggung Jawab Siswa dalam Pembelajaran Daring di kelas V SDN Gugus II Kota Bengkulu

This study aims to analyze the effect of authoritarian, democratic, and permissive parenting on the responsible attitude of fifth graders in online learning at SDN Gugus II Bengkulu City. This type of quantitative research with comparative causal research method. The research population was all students of class V SDN Cluster II Bengkulu City, which amounted to 114 students. The sample in this study was 29 students from 114 populations. The data collection technique used a parenting style questionnaire consisting of 35 items and a student responsibility attitude questionnaire consisting of 27 items. The data analysis technique in this study used simple linear regression. The results showed that the value of tcount > ttable (3.731 > 2.056) with a significance level of = 0.05 (0.001> 0.05) and a large contribution of 34%. Furthermore, the results of the research on each aspect, namely, (1) authoritarian parenting pattern obtained t count 3.483 > 2.056 with a significance level of 0.002 < 0.05 and the amount of the contribution of 31%. (2) the results of the calculation of democratic parenting obtained tcount 4.133 > 2.056 with a significance level of 0.000 <0.05 and the amount of contribution 38.7% (3) the results of the calculation of democratic parenting obtained tcount of 1.080 < 2.056 with a contribution of 3.8 % with a significance level of 0.308 > 0.05. The conclusion in this study is that there is an influence of parenting styles on students' responsible attitudes and there is also an influence of parenting styles on aspects of authoritarian and democratic parenting on students' responsible attitudes, while permissive parenting has no effect on responsible attitudes. Keywords: Parenting Styles, Responsibility Attitude, online learning 

Operational performance of a PV generator feeding DC shunt and induction motors with MPPT

This paper presented the transient and operational behavior of a parallel Combination of DC Shunt Motor and IM fed by a photovoltaic generator at different solar irradiance levels. The maximum power point of current/voltage (I/V) characteristic of the PV generator was achieved for different solar intensities, by utilizing an open circuit voltage method. The nonlinear operational behavior of (I/V) characteristics of the PV generator at various solar intensities and the magnetization curve of the ferromagnetic material of the DC shunt motor were both modeled by high order polynomial mathematical expressions. The study investigated the response of the system at different solar irradiance levels and changing the torque loads for both motors and then following step change in solar intensity levels with fixed loading torques for both motors. All numerical simulations were executed using MATLAB software