scholarly journals Stationary regime for a queue of the type M|M|c|c + m with constant retrial rate

2020 ◽  
pp. 22-31
Author(s):  
E.A. Lebedev ◽  
◽  
V.D. Ponomarov ◽  
Keyword(s):  
Stationary Regime ◽  
Constant Retrial Rate

Application of Mathematical Modeling during Monitoring and Optimization of Non-Stationary Regime of Oil Well

2016 ◽  
Vol 11 (1) ◽  
pp. 53-59
Author(s):  
A.S. Topolnikov
Keyword(s):  
Mathematical Modeling ◽  
Model Problem ◽  
Cylindrical Tube ◽  
Field Measurements ◽  
Stationary Flow ◽  
Stationary Regime ◽  
Oil Well ◽  
Time Duration ◽  
Typical Time ◽  
Radial Model

The paper presents results of modeling of periodical regime of oil well for the purpose of monitoring and optimization of its operation. To describe non-stationary flow in the reservoir a planar-radial model of filtration is employed. The flow of multiphase flux in the well elements (casing, tubing, annulus) is described by 1D Navier-Stoks equations. The pump work is modelled by specification of its rate-head curve. To estimate the typical time duration of the processes in the well and in the reservoir a solution of a model problem for cylindrical tube is given. Through the examples a solution of a problem of optimization of periodical regime of oil wells is demonstrated. The comparison with field measurements is presented.

scholarly journals Comparison of the thermal performance between conventional and cob building

2019 ◽  
Vol 111 ◽  
pp. 03003
Author(s):  
Kaoutar Zeghari ◽  
Hasna Louahlia ◽  
Malo Leguern ◽  
Mohamed Boutouil ◽  
Hamid Gualous ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Behaviour ◽  
Calculation Method ◽  
Building Materials ◽  
Residential Building ◽  
Local Heat ◽  
Energy Performance ◽  
Stationary Regime ◽  
Thermal Regulation ◽  
Climate Data

The appliance of sustainable development approach in building has urged construction industry to adopt proper measurements to protect environment and reduce residential building energy consumption and CO2 emissions. Thus, an increasing interest in alternative building materials has developed including the use of bio-based materials such as cob which is studied in this paper. In the previous work, many experimental and numerical studies have been carried out to characterize thermal behaviour of earth buildings, reduce its thermal conductivity and water content. In this paper, an experimental study is carried out to determine the thermal properties and energy performance of cob building. Cob samples within different soil and fiber contents are studied using an experimental set up instrumented with flux meters and micro-thermocouples in order to evaluate the local heat flux and thermal conductivity during stationary regime. The results are analysed and compared to deduce the performant mixes in terms of thermal behaviour while respecting the French thermal regulation. A static thermal simulation based on RT 2012 calculation method (the official French calculation method for the energy performance of new residential and commercial buildings according to France thermal regulation) is used to compare energy performance between conventional and cob building using the French climate data base .

scholarly journals Boundary behavior and product-form stationary distributions of jump diffusions in the orthant with state-dependent reflections

2008 ◽  
Vol 40 (02) ◽  
pp. 529-547
Author(s):  
Francisco J. Piera ◽  
Ravi R. Mazumdar ◽  
Fabrice M. Guillemin
Keyword(s):  
Random Fields ◽  
Diffusion Coefficients ◽  
Boundary Behavior ◽  
Stationary Regime ◽  
Product Form ◽  
Local Times ◽  
Nonnegative Orthant ◽  
State Dependent ◽  
The Times ◽  
And Diffusion

In this paper we consider reflected diffusions with positive and negative jumps, constrained to lie in the nonnegative orthant of ℝ n . We allow for the drift and diffusion coefficients, as well as for the directions of reflection, to be random fields over time and space. We provide a boundary behavior characterization, generalizing known results in the nonrandom coefficients and constant directions of the reflection case. In particular, the regulator processes are related to semimartingale local times at the boundaries, and they are shown not to charge the times the process expends at the intersection of boundary faces. Using the boundary results, we extend the conditions for product-form distributions in the stationary regime to the case when the drift and diffusion coefficients, as well as the directions of reflection, are random fields over space.

Bromate Reaction on a Rotating Disc Electrode: A New Method of Obtaining Approximate Analytical Solutions for Stationary Regime

2018 ◽  
Vol 483 (1) ◽  
pp. 256-260
Author(s):  
M. A. Vorotyntsev ◽  
A. E. Antipov ◽  
M. M. Petrov ◽  
R. D. Pichugov ◽  
E. I. Borisevich ◽  
...  
Keyword(s):  
Analytical Solutions ◽  
Stationary Regime ◽  
New Method ◽  
Rotating Disc Electrode ◽  
Disc Electrode ◽  
Rotating Disc ◽  
Approximate Analytical Solutions

scholarly journals Poisson hail on a hot ground

2011 ◽  
Vol 48 (A) ◽  
pp. 343-366
Author(s):  
Francois Baccelli ◽  
Sergey Foss
Keyword(s):  
Euclidean Space ◽  
Service Time ◽  
Evolution Equations ◽  
Stationary Regime ◽  
Service Discipline ◽  
Closed Sets ◽  
Random Closed Sets ◽  
Exponential Moments ◽  
First In First Out ◽  
Arrival Intensity

We consider a queue where the server is the Euclidean space, and the customers are random closed sets (RACSs) of the Euclidean space. These RACSs arrive according to a Poisson rain and each of them has a random service time (in the case of hail falling on the Euclidean plane, this is the height of the hailstone, whereas the RACS is its footprint). The Euclidean space serves customers at speed 1. The service discipline is a hard exclusion rule: no two intersecting RACSs can be served simultaneously and service is in the first-in–first-out order, i.e. only the hailstones in contact with the ground melt at speed 1, whereas the others are queued. A tagged RACS waits until all RACSs that arrived before it and intersecting it have fully melted before starting its own melting. We give the evolution equations for this queue. We prove that it is stable for a sufficiently small arrival intensity, provided that the typical diameter of the RACS and the typical service time have finite exponential moments. We also discuss the percolation properties of the stationary regime of the RACS in the queue.

scholarly journals The glow duration time influence on the ionization rate detected in the diodes filled with noble gases on mbar pressures

2003 ◽  
Vol 2 (5) ◽  
pp. 259-267 ◽  
Author(s):  
Olivera Stepanovic ◽  
Miodrag Radovic ◽  
Cedomir Maluckov
Keyword(s):  
Electrical Breakdown ◽  
Measuring Method ◽  
Stationary Regime ◽  
Ionization Rate ◽  
Relaxation Period ◽  
Breakdown Time ◽  
Duration Time ◽  
Current Duration ◽  
Helium Neon ◽  
Ionization Rates

The results of the glow current duration time (glowing-time) influence on the ionization rate detected in the gas filled diodes are presented. The electrical breakdown was detected as the minimal current impulse. After that diode glow from the minimal glowing-time (10-3 s), up to the maximal 103 s which overlap the time of the stationary regime formation in the gas diode tube. The diodes were with volumes of 300 cm3, but with a diode gap volume of about 1 cm3 and filled with helium, neon, argon or krypton, at the pressures of the order of mbar. The ionization rates were detected as the residual ionization after the glowing was interrupted, using the electrical breakdown time delay measuring method. The influence of the gap distance stationary current values and the relaxation period were also investigated. The result shows that the stationary regime in such a gas diode is established after the glowing time of 1-3 s, although the breakdown formative times were smaller then 1 ms.

scholarly journals The properties of the queuing model with the parallel structure

2020 ◽  
pp. 79-82
Author(s):  
O. A. Chechelnitsky
Keyword(s):  
Stationary Regime ◽  
Parallel Structure ◽  
Stochastic Dynamic ◽  
General Function ◽  
Expected Number ◽  
Queuing Model ◽  
Poisson Input ◽  
Infinite Server Queues ◽  
Result Analysis ◽  
Number Of Customers

The present article is devoted to research the multi-channelk model with the parallel structure. It means that we consider the model which consists of two infinite-server queues. The service time in the each system has general function of distribution. In this case the stochastic dynamic of our model cannot be defined by Markov chain. As a result, analysis of such models is much more difficult than that of the corresponding Markovian queueing models. Besides we assume that customers arrive to our model according a bivariate Poisson input flow. This input process is characterized by the fact that customers arrive according to a bivariate Poisson flow simultaneously. We consider the number of customers in the systems at time t. This stochastic process describes the state of our model. In present paper we find the limit joint distribution of the number of customers in the systems. In a general way (by differentiating the corresponding generating function.) we obtain the main characteristics of this distribution, such as the expected number of customers in the nodes, its variance and correlation. In the case when parameters of our model dependent on the parameter n (number of series) the limit normal distribution was obtained for the service process in the stationary regime.

Sign in / Sign up

Export Citation Format

Share Document