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Double Lid Driven Cavity with Different Moving Wall Directions for Low Reynolds Number Flow
Kajal Chandra Saha,
Goutam Saha,
Doli Rani Pal
Issue:
Volume 4, Issue 3, September 2018
Pages:
67-72
Received:
14 August 2018
Accepted:
30 August 2018
Published:
15 October 2018
Abstract: In this paper, a numerical examination used to analyze the flow and heat transfer characteristics inside a double lid-driven cavity underneath buoyancy consequences of thermal diffusion. The lid is due to the movement of the isothermal vertical sidewalls of different constant temperatures, while other walls are kept adiabatic. Also, the upright walls are moving at a constant rate and four different moving wall directions are considered along these walls. Further, the governing equations of the flow and thermal fields are transformed into dimensionless equations and then solved numerically using finite difference method. A contrast of the current learn is additionally carried out with the formerly published works and observed excellent agreement. Moreover, the results from numerical simulations have been presented in the form of velocities and isothermal profiles, shown graphically and discussed for different Reynolds number. Result unveils that, the influence of the development of the velocity profiles in the chamber decreases with the augmentation of Re. Besides, the intensification of Reynolds number ends in forming diminution of thermal boundary layers near the heated wall. In addition, the maximum Average Nusselt number can be obtained when the left lid poignant towards positive direction and the right lid poignant to the same direction.
Abstract: In this paper, a numerical examination used to analyze the flow and heat transfer characteristics inside a double lid-driven cavity underneath buoyancy consequences of thermal diffusion. The lid is due to the movement of the isothermal vertical sidewalls of different constant temperatures, while other walls are kept adiabatic. Also, the upright wal...
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The Effect of Hermanson’s Spatial Dielectric Function on the Density of Impurity States in a Gallium Arsenide Quantum Dot of Rectangular Cross-Section
Leonard Machuka,
Hannigton Odhiambo Oyoko
Issue:
Volume 4, Issue 3, September 2018
Pages:
73-77
Received:
19 August 2018
Accepted:
17 September 2018
Published:
17 October 2018
Abstract: We have carried out a theoretical study of the effect of Hermanson’s spatial dielectric function on the density of impurity states (DOIS) for a shallow hydrogenic donor impurity located in the center of a Gallium Arsenide (GaAs) Quantum Well Dot (QWD) of rectangular cross-section. The density of impurity states (DOIS) of an unscreened (hydrogenic) donor impurity was calculated and compared with that of the screened (non-hydrogenic) donor impurity for the same system. Our calculations were carried out using a trial wave function within the effective mass approximation. Our calculations have been carried out with finite barriers. In this study, we first calculated the ground state binding energies of both hydrogenic and non-hydrogenic donor impurity for different dot sizes. The donor binding energies in the two regimes are then used to compute the DOIS. The results show that for both hydrogenic and non-hydrogenic donor impurities, the DOIS sharply rises to a peak, and then decreases almost exponentially with increase in binding energy. The results also show that the DOIS obtained for the non-hydrogenic donor impurities is markedly enhanced over that for purely hydrogenic donor impurities in which a dielectric constant is employed in the potential. In fact, the enhanced DOIS is observed throughout the range of values for binding energy considered. To a good extend there is good agreement between our results and those reported in the literature. It is therefore, important that the effect of the spatial dielectric function should be considered when designing optoelectronic devices.
Abstract: We have carried out a theoretical study of the effect of Hermanson’s spatial dielectric function on the density of impurity states (DOIS) for a shallow hydrogenic donor impurity located in the center of a Gallium Arsenide (GaAs) Quantum Well Dot (QWD) of rectangular cross-section. The density of impurity states (DOIS) of an unscreened (hydrogenic) ...
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Global Asymptotic Stability for a New Class of Neutral Neural Networks
Ricai Luo,
Gang Lin,
Dongdong Yin
Issue:
Volume 4, Issue 3, September 2018
Pages:
78-83
Received:
28 August 2018
Accepted:
17 October 2018
Published:
9 November 2018
Abstract: In the present world, due to the complicated dynamic properties of neural cells, many dynamic neural networks are described by neutral functional differential equations including neutral delay differential equations. These neural networks are called neutral neural networks or neural networks of neural-type. The differential expression not only defines the derivative term of the current state but also explains the derivative term of the past state. In this paper, global asymptotic stability of a neutral-type neural networks, with time-varying delays, are presented and analyzed. The neural network is made up of parts that include: linear, non-linear, non-linear delayed, time delays in time derivative states, as well as a part of activation function with the derivative. Different from prior references, as part of the considered networks, the last part involves an activation function with the derivative rather than multiple delays; that is a new class of neutral neural networks. This paper assumes that the activation functions satisfy the Lipschitz conditions so that the considered system has a unique equilibrium point. By constructing a Lyapunov-Krasovskii-type function and by using a linear matrix inequality analysis technique, a sufficient condition for global asymptotic stability of this neural network has been obtained. Finally, we present a numerical example to show the effectiveness and applicability of the proposed approach.
Abstract: In the present world, due to the complicated dynamic properties of neural cells, many dynamic neural networks are described by neutral functional differential equations including neutral delay differential equations. These neural networks are called neutral neural networks or neural networks of neural-type. The differential expression not only defi...
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Observation of Different Behaviors of Logistic Map for Different Control Parameters
Musammet Tahmina Akter,
Mohammad Abul Mansur Chowdhury
Issue:
Volume 4, Issue 3, September 2018
Pages:
84-90
Received:
3 October 2018
Accepted:
8 November 2018
Published:
4 December 2018
Abstract: The logistic map is one of the most important but common examples of chaotic dynamics. The object shows the crucial belief of the deterministic chaos theory that brings a new procedural structure and apparatus for exploring and understanding complex behavior in dynamical systems. We put an importance on report of the Verhulst logistic map which is one of the potential models and methods for researching dynamical systems that could develop to chaotic. Chaotic signals present a special difficulty in parameter estimation. The difficulty arises from the definition of a chaotic system because of sensitive dependence on initial conditions. It is seen that very slight changes in the initial conditions cause significant effects in the evolution. In general the chaotic systems are nonlinear and apparently random but they are deterministic. The main objective of this paper is how can find the logistic map equation and investigated the chaotic behavior for the logistic equation by varying the control parameters and finally discover Lyaponov exponent, Bifurcation diagrams etc.
Abstract: The logistic map is one of the most important but common examples of chaotic dynamics. The object shows the crucial belief of the deterministic chaos theory that brings a new procedural structure and apparatus for exploring and understanding complex behavior in dynamical systems. We put an importance on report of the Verhulst logistic map which is ...
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