scholarly journals A Nonlinear Dynamical Model to Study the Removal of Gaseous and Particulate Pollutants in a Rain System

2007 ◽  
Vol 12 (2) ◽  
pp. 227-243
Author(s):  
R. Naresh ◽  
S. Sundar
Keyword(s):  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Gaseous Pollutants ◽  
Particulate Matters ◽  
Nonlinear Mathematical Model ◽  
Nonlinear Dynamical ◽  
Particulate Pollutants ◽  
Rain Drops ◽  
Ecological Type ◽  
Very High

An ecological type nonlinear mathematical model is proposed to study the removal of gaseous pollutants and two distinct particulate matters by precipitation scavenging in the atmosphere. The atmosphere during precipitation consists of five interacting phases namely the raindrops phase, the gaseous pollutants phase, the smaller particulate matters phase, the larger particulate matters phase and the absorbed phase of gaseous pollutants. We assume that gaseous pollutants are removed from the atmosphere by the processes of impaction as well as by absorption while particulate matters are assumed to be removed by impaction process. The model is analyzed using stability theory of nonlinear differential equations. It is shown that, under appropriate conditions, the pollutants can be removed from the atmosphere and their removal rates would depend mainly upon the rates of emission of pollutants, rate of rain drops formation and the rate of raindrops falling on the ground. If the rate of precipitation is very high, all the pollutants (gaseous as well as particulate matters) would be removed completely from the atmosphere. A numerical study is also performed to study the dynamics of the model system. The results are found to be in line with the experimental observations published in the literature.

scholarly journals MODELLING AND ANALYSIS OF HIV‐TB CO‐INFECTION IN A VARIABLE SIZE POPULATION

2005 ◽  
Vol 10 (3) ◽  
pp. 275-286 ◽  
Author(s):  
R. Naresh ◽  
A. Tripathi
Keyword(s):  
Mathematical Model ◽  
Stability Theory ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Transmission Dynamics ◽  
Nonlinear Mathematical Model ◽  
Variable Size ◽  
Size Population ◽  
Globally Stable ◽  
Disease Free

In this paper, a nonlinear mathematical model is proposed for the transmission dynamics of HIV and a curable TB pathogen within a population of varying size. In the model, we have divided the population into four sub classes of susceptibles, TB infectives, HIV infectives and that of AIDS patients. The model exhibits four equillibria namely, a disease free, HIV free, TB free and a co‐infection equilibrium. The model has been studied qualitatively using stability theory of nonlinear differential equations. It is shown that the positive co‐infection equilibrium is always locally stable but it may become globally stable under certain conditions showing that the disease becomes endemic due to constant migration of the population into the habitat. A numerical study of the model is also performed to investigate the influence of certain key parameters on the spread of the disease. Šiame darbe pateikiamas netiesinis matematinis modelis, skirtas aprašyti ŽIV ir išgydomo TB patogeno plitimui kintamo dydžio populiacijoje. Modelyje populiacija dalinama i keturias klases – galintys užsikresti, TB infekuoti, ŽIV infekuoti ir AIDS pacientai. Modelis turi keturias pusiausvyros padetis: nesergantys, nesergantys ŽIV, nesergantys TB ir sergantys abiem ligom. Modelis analizuojamas kokybiniu požiūriu, naudojant netiesiniu diferencialiniu lygčiu stabilumo teorija. Irodyta, kad teigiama dvieju infekciju pusiausvyros padetis visada yra lokaliai stabili, be to, esant tam tikroms salygoms, ta padetis taip pat būna ir globaliai stabili. Tai reiškia, kad esant pastoviai migracijai i areala, liga tampa endemine. Atlikta modelio skaitine analize, skirta nagrineti kai kuriu svarbiausiu parametru itaka AIDS ir TB ligu plitimui.

An Automated Mobile Laboratory for Continuous Monitoring of Atmospheric Pollutants

1980 ◽  
Vol 194 (1) ◽  
pp. 357-364
Author(s):  
R. M. Harrison ◽  
H. A. McCartney
Keyword(s):  
Continuous Monitoring ◽  
Air Pollutant ◽  
Atmospheric Pollutants ◽  
Gaseous Pollutants ◽  
Mobile Laboratory ◽  
Digital Form ◽  
Pollutant Concentrations ◽  
Particulate Pollutants ◽  
Nitrate Fertilizer ◽  
Wet Chemical

The construction and operation of an automated mobile laboratory for continuous air pollutant monitoring are described. The gaseous pollutants sulphur dioxide, nitric oxide, nitrogen dioxide and ozone are monitored continuously, whilst particulate pollutants are collected for subsequent wet chemical analysis. Gaseous pollutant concentrations together with measurements of wind direction and speed and solar radiation are recorded continuously in both analogue and digital form. The problems inherent in siting and operating the mobile laboratory are discussed and the analysis of monitoring data is illustrated with reference to a recent survey carried out in the vicinity of an ammonium nitrate fertilizer works.

A Topological Study of the Genesis of a Horseshoe Vortex in the Symmetry Plane Due to an Adverse Pressure Gradient

2001 ◽  
Author(s):  
Martijn A. van den Berg ◽  
Michael M. J. Proot ◽  
Peter G. Bakker
Keyword(s):  
Pressure Gradient ◽  
Bifurcation Theory ◽  
Nonlinear Differential Equations ◽  
Nonlinear Dynamical System ◽  
Symmetry Plane ◽  
Adverse Pressure Gradient ◽  
Horseshoe Vortex ◽  
Nonlinear Dynamical ◽  
Separating Flow ◽  
Flow Through

Abstract The present paper describes the genesis of a horseshoe vortex in the symmetry plane in front of a juncture. In contrast to a previous topological investigation, the presence of the obstacle is no longer physically modelled. Instead, the pressure gradient, induced by the obstacle, has been used to represent its influence. Consequently, the results of this investigation can be applied to any symmetrical flow above a flat plate. The genesis of the vortical structure is analysed by using the theory of nonlinear differential equations and the bifurcation theory. In particular, the genesis of a horseshoe vortex can be described by the unfolding of the degenerate singularity resulting from a Jordan Normal Form with three vanishing eigenvalues and one linear term which is related to the adverse pressure gradient. The examination of this nonlinear dynamical system reveals that a horseshoe vortex emanates from a non-separating flow through two subsequent saddle-node bifurcations in different directions and the transition of a node into a focus located in the flow field.

scholarly journals Cumulative Impact of Micropolar Fluid and Porosity on MHD Channel Flow: A Numerical Study

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
Kottakkaran Sooppy Nisar ◽  
Aftab Ahmed Faridi ◽  
Sohail Ahmad ◽  
Nargis Khan ◽  
Kashif Ali ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Chemical Reaction ◽  
Micropolar Fluid ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
X Rays ◽  
Cumulative Impact ◽  
Transfer Rates ◽  
Mass And Heat Transfer ◽  
The Impact

The mass and heat transfer magnetohydrodynamic (MHD) flows have a substantial use in heat exchangers, electromagnetic casting, X-rays, the cooling of nuclear reactors, mass transportation, magnetic drug treatment, energy systems, fiber coating, etc. The present work numerically explores the mass and heat transportation flow of MHD micropolar fluid with the consideration of a chemical reaction. The flow is taken between the walls of a permeable channel. The quasi-linearization technique is utilized to solve the complex dynamical coupled and nonlinear differential equations. The consequences of the preeminent parameters are portrayed via graphs and tables. A tabular and graphical comparison evidently reveals a correlation of our results with the existing ones. A strong deceleration is found in the concentration due to the effect of a chemical reaction. Furthermore, the impact of the magnetic field force is to devaluate the mass and heat transfer rates not only at the lower but at the upper channel walls, likewise.

scholarly journals The use of mathematical modeling methods for solving geo-ecological problems of sustainable development of regions

2020 ◽  
Vol 161 ◽  
pp. 01005
Author(s):  
M V Volik
Keyword(s):  
Mathematical Modeling ◽  
Air Pollution ◽  
Sustainable Development ◽  
Numerical Study ◽  
Digital Technologies ◽  
Motor Vehicles ◽  
Gaseous Pollutants ◽  
Mathematical Apparatus ◽  
Modeling Methods ◽  
Ecological Problems

Currently, a number of environmental problems have a significant impact on the stable economic development of the country. A global problem is the study of air pollution. The solution of such geoecological problems should be carried out with the use of modern mathematical apparatus and digital technologies. The paper presents the results of a numerical study of the distribution of gaseous pollutants emitted by motor vehicles in the pedestrian zone of streets. It is shown that the vortex structures formed in the studied city buildings development have a significant impact on the accumulation of anthropogenic impurities.

Unsteady and Calming Effects Investigation on a Very High Lift LP Turbine Blade: Part I — Experimental Analysis

2002 ◽  
Author(s):  
Thomas Coton ◽  
Tony Arts ◽  
Michae¨l Lefebvre ◽  
Nicolas Liamis
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Numerical Study ◽  
Turbine Rotor ◽  
High Lift ◽  
Turbine Rotor Blade ◽  
Pressure Loss Coefficient ◽  
Lp Turbine ◽  
Exit Mach Number ◽  
Very High

An experimental and numerical study was performed about the influence of incoming wakes and the calming effect on a very high lift low pressure turbine rotor blade. The first part of the paper describes the experimental determination of the pressure loss coefficient and the heat transfer around the blade mounted in a high speed linear cascade. The cascade is exposed to incoming wakes generated by high speed rotating bars. Their aim is to act upon the transition/separation phenomena. The measurements were conducted at a constant exit Mach number equal to 0.8 and at three Reynolds number values, namely 190000, 350000 and 650000. The inlet turbulence level was fixed at 0.8%. An additional feature of this work is to identify the boundary layer status through heat transfer measurements. Compared to the traditionally used hot films, thin film heat flux gages provide fully quantitative data required for code validation. Numerical computations are presented in the second part of the paper.

scholarly journals Parallel Numerical Simulation of the Magnetic Moment Reversal within the φ0-Josephson Junction Spintronic Model

2020 ◽  
Vol 226 ◽  
pp. 02018
Author(s):  
Stefani Panayotova ◽  
Maxim Bashashin ◽  
Elena Zemlyanaya ◽  
Pavlina Atanasova ◽  
Yury Shukrinov ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Magnetic Moment ◽  
Information Technologies ◽  
Parallel Implementation ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Computer Code ◽  
Computer Time ◽  
Physical Parameters ◽  
Wide Range

The φ0-Josephson Dushanbe, Tajikistanjunction model with a coupling between the magnetic moment and the Josephson current in the “superconductor–ferromagnet–superconductor” system has been investigated. Numerical solution of the respective system of nonlinear differential equations is based on the two-stage Gauss–Legendre algorithm. For numerical simulation in a wide range of parameters which requires a significant computer time, a parallel MPI=C++ computer code has been developed. Results of numerical study of the magnetization effect depending on physical parameters, as well as results of methodological calculations demonstrating the efficiency of the parallel implementation, are presented. Calculations have been carried out at the Heterogeneous Platform “HybriLIT” and on the supercomputer “Govorun” of the Multifunctional Information and Computing Complex of the Laboratory of Information Technologies, JINR (Dubna).

Sign in / Sign up

Export Citation Format

Share Document