scholarly journals Particle-Based Modeling of Electron–Phonon Interactions

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Flavio F. M. Sabatti ◽  
Stephen M. Goodnick ◽  
Marco Saraniti
Keyword(s):  
Steady State ◽  
Point Process ◽  
Mathematical Description ◽  
Statistical Weight ◽  
The State ◽  
Transient Simulation ◽  
Thinning Algorithm ◽  
Numerical Problem ◽  
Energy Error ◽  
Important Challenge

Abstract An important challenge in particle-based modeling of electron–phonon interactions is the large difference in the statistical weight of the particles in the two simulated populations. Each change in the state of a simulated phonon during scattering is statistically representative of an interaction with multiple simulated electrons, which results in a large numerical burden accurately represent both populations. We developed two stochastic approaches to mitigate this numerical problem. The first approach is based on Poisson modeling of the scattering processes coupled with a thinning algorithm, which works effectively at steady-state, but it is prone to statistical errors in the energy during the transient regime. The second approach is based on point process (PP) modeling of the scattering, allowing stochastical book-keeping, which corrects the energy error. Here, we present a mathematical description of the problem and the two stochastic approaches along with the numerical results we obtained for the synchronous transient simulation of the electron and phonon populations.

scholarly journals Steady State Response of Linear Time Invariant Systems Modeledby Multibond Graphs

2021 ◽  
Vol 11 (4) ◽  
pp. 1717
Author(s):  
Gilberto Gonzalez Avalos ◽  
Noe Barrera Gallegos ◽  
Gerardo Ayala-Jaimes ◽  
Aaron Padilla Garcia
Keyword(s):  
Steady State ◽  
Linear Time ◽  
Direct Determination ◽  
The State ◽  
Steady State Response ◽  
State Variables ◽  
Linear Time Invariant ◽  
State Response ◽  
Time Invariant

The direct determination of the steady state response for linear time invariant (LTI) systems modeled by multibond graphs is presented. Firstly, a multiport junction structure of a multibond graph in an integral causality assignment (MBGI) to get the state space of the system is introduced. By assigning a derivative causality to the multiport storage elements, the multibond graph in a derivative causality (MBGD) is proposed. Based on this MBGD, a theorem to obtain the steady state response is presented. Two case studies to get the steady state of the state variables are applied. Both cases are modeled by multibond graphs, and the symbolic determination of the steady state is obtained. The simulation results using the 20-SIM software are numerically verified.

Marked point processes as limits of Markovian arrival streams

1993 ◽  
Vol 30 (02) ◽  
pp. 365-372 ◽  
Author(s):  
Søren Asmussen ◽  
Ger Koole
Keyword(s):  
Point Process ◽  
Point Processes ◽  
Marked Point ◽  
The State ◽  
Marked Point Processes ◽  
Marked Point Process ◽  
State Transitions ◽  
Poisson Arrival ◽  
Convergence Of Moments ◽  
Environmental Process

A Markovian arrival stream is a marked point process generated by the state transitions of a given Markovian environmental process and Poisson arrival rates depending on the environment. It is shown that to a given marked point process there is a sequence of such Markovian arrival streams with the property that as m →∞. Various related corollaries (involving stationarity, convergence of moments and ergodicity) and counterexamples are discussed as well.

Hydrodynamic Analysis of Fluid Effect in Rigid Rectangular Tank due to Harmonic Motion

2014 ◽  
Vol 635 ◽  
pp. 147-150 ◽  
Author(s):  
Kamila Kotrasova ◽  
Eva Kormaníková
Keyword(s):  
Steady State ◽  
Numerical Modelling ◽  
Problem Analysis ◽  
Hydrodynamic Analysis ◽  
Reciprocal Interaction ◽  
Harmonic Motion ◽  
Numerical Problem ◽  
Steady State Motion ◽  
Rectangular Tank

Ground-supported tanks are used to store a variety of liquids. This paper deals possibility numerical modelling reciprocal interaction moving container with fluid in under consideration horizontal harmonic motion reservoirs. It clarify watched phenomenon, illustrate pressure process at a walls of container, from witch it results action of force at a container. The numerical problem analysis is comparing with realised experiment, where steady state motion of fluid was watched and his maximum wave of fluid on the walls of reservoirs.

3D steady state and transient simulation tools for heat transfer and solidification in continuous casting

2005 ◽  
Vol 413-414 ◽  
pp. 135-138 ◽  
Author(s):  
Seppo Louhenkilpi ◽  
Mika Mäkinen ◽  
Sami Vapalahti ◽  
Tuomo Räisänen ◽  
Jukka Laine
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Continuous Casting ◽  
Transient Simulation ◽  
Simulation Tools ◽  
Heat Transfer And Solidification

On arrivals that see time averages: a martingale approach

1990 ◽  
Vol 27 (2) ◽  
pp. 376-384 ◽  
Author(s):  
Benjamin Melamed ◽  
Ward Whitt
Keyword(s):  
Steady State ◽  
Point Process ◽  
Point Processes ◽  
Steady State Distribution ◽  
State Distribution ◽  
Martingale Theory ◽  
Stochastic Intensity ◽  
Sample Paths ◽  
Time Averages ◽  
Definition Of

This paper is a sequel to our previous paper investigating when arrivals see time averages (ASTA) in a stochastic model; i.e., when the steady-state distribution of an embedded sequence, obtained by observing a continuous-time stochastic process just prior to the points (arrivals) of an associated point process, coincides with the steady-state distribution of the observed process. The relation between the two distributions was also characterized when ASTA does not hold. These results were obtained using the conditional intensity of the point process given the present state of the observed process (assumed to be well defined) and basic properties of Riemann–Stieltjes integrals. Here similar results are obtained using the stochastic intensity associated with the martingale theory of point processes, as in Brémaud (1981). In the martingale framework, the ASTA result is almost an immediate consequence of the definition of a stochastic intensity. In a stationary framework, the results characterize the Palm distribution, but stationarity is not assumed here. Watanabe's (1964) martingale characterization of a Poisson process is also applied to establish a general version of anti–PASTA: if the points of the point process are appropriately generated by the observed process and the observed process is Markov with left-continuous sample paths, then ASTA implies that the point process must be Poisson.

scholarly journals Fluorescence investigation of epoxy resin LG 285 and mathematical description of the curing process

2019 ◽  
Vol 292 ◽  
pp. 01025
Author(s):  
Michaela Mikuličová ◽  
Vladimír Vašek ◽  
Vojtěch Křesálek
Keyword(s):  
Steady State ◽  
Fluorescence Spectroscopy ◽  
Epoxy Resin ◽  
Mathematical Description ◽  
Curing Process ◽  
Steady State Fluorescence ◽  
Two Component ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Steady State Fluorescence Spectroscopy

In this paper, steady-state fluorescence spectroscopy is used to investigate the curing of two-component epoxy resin LG 285. Moreover, the process of curing is mathematically described. The mixture of resin and hardener HG 287 is measured at five different temperatures (50 °C, 60 °C, 70 °C, 80 °C and 90 °C) for five and a half hours. The results indicate that the process of curing of epoxy resin decelerates with time and accelerates with increasing temperature. Furthermore, the energy of the barrier is calculated.

scholarly journals The steady-state behaviour of multistate monotone systems

1984 ◽  
Vol 21 (04) ◽  
pp. 826-835 ◽  
Author(s):  
Bent Natvig ◽  
Arnfried Streller
Keyword(s):  
Steady State ◽  
Explicit Formula ◽  
Point Process ◽  
Critical Level ◽  
Monotone Systems ◽  
State Behaviour ◽  
The Mean ◽  
Stationary Interval ◽  
Mean Time ◽  
Steady State Behaviour

In this paper the steady-state behaviour of multistate monotone systems of multistate components is considered by applying the theory for stationary and synchronous processes with an embedded point process. After reviewing some general results on stationary availability, stationary interval availability and stationary mean interval performance probabilities, we concentrate on systems with independently working and separately maintained components. For this case an explicit formula is given for the mean time which the system in steady state sojourns in states not below a fixed critical level.

scholarly journals Homeostatic Adjustment and Metabolic Remodeling in Glucose-limited Yeast Cultures

2005 ◽  
Vol 16 (5) ◽  
pp. 2503-2517 ◽  
Author(s):  
Matthew J. Brauer ◽  
Alok J. Saldanha ◽  
Kara Dolinski ◽  
David Botstein
Keyword(s):  
Gene Expression ◽  
Growth Rate ◽  
Steady State ◽  
Stress Response ◽  
The State ◽  
Second Phase ◽  
Diauxic Shift ◽  
Batch Cultures ◽  
Chemostat Cultures ◽  
Metabolic Remodeling

We studied the physiological response to glucose limitation in batch and steady-state (chemostat) cultures of Saccharomyces cerevisiae by following global patterns of gene expression. Glucose-limited batch cultures of yeast go through two sequential exponential growth phases, beginning with a largely fermentative phase, followed by an essentially completely aerobic use of residual glucose and evolved ethanol. Judging from the patterns of gene expression, the state of the cells growing at steady state in glucose-limited chemostats corresponds most closely with the state of cells in batch cultures just before they undergo this “diauxic shift.” Essentially the same pattern was found between chemostats having a fivefold difference in steady-state growth rate (the lower rate approximating that of the second phase respiratory growth rate in batch cultures). Although in both cases the cells in the chemostat consumed most of the glucose, in neither case did they seem to be metabolizing it primarily through respiration. Although there was some indication of a modest oxidative stress response, the chemostat cultures did not exhibit the massive environmental stress response associated with starvation that also is observed, at least in part, during the diauxic shift in batch cultures. We conclude that despite the theoretical possibility of a switch to fully aerobic metabolism of glucose in the chemostat under conditions of glucose scarcity, homeostatic mechanisms are able to carry out metabolic adjustment as if fermentation of the glucose is the preferred option until the glucose is entirely depleted. These results suggest that some aspect of actual starvation, possibly a component of the stress response, may be required for triggering the metabolic remodeling associated with the diauxic shift.

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