652 publications from this institution
This paper suggests a new method for fabrication of nanofibers with polymer liquid membrane, which is produced by a metal ring rotating through the polymer solution. The thickness of the produced membrane is thin and suitable for nanomaterial fabrication. In this paper the membrane is to form a polymer bubble by blowing air under the presence of a high electronic field, and multiple jets eject when the bubble is ruptured. The effect of applied voltage on the fiber diameter is studied.
Article A Generalized Variational Principle for 3-D Unsteady Transonic Rotational Flow in Rotor Using Clebsch Variables was published on March 1, 1997 in the journal International Journal of Turbo & Jet-Engines (volume 14, issue 1).
Nonlinear phenomena appear everywhere in our daily life and our scientific works, and today nonlinear science represents one of the most challenging, promising, and romantic fields of research in s...
Hierarchical structures always have similar scaling laws both in biology and physics, and the scaling exponent plays an import role in sighting into the physiological properties or physical properties of the studied problems. E-infinity theory is emphasized and is predicted to be the most promising theory for natural hierarchical structures.
A critical hurdle of a nonlinear vibration system in a fractal space is the inefficiency in modelling the system. Specifically, the differential equation models cannot elucidate the effect of porosity size and distribution of the periodic property. This paper establishes a fractal-differential model for this purpose, and a fractal Duffing-Van der Pol oscillator (DVdP) with two-scale fractal derivatives and a forced term is considered as an example to reveal the basic properties of the fractal oscillator. Utilizing the two-scale transforms and He-Laplace method, an analytic approximate solution may be attained. Unfortunately, this solution is not physically preferred. It has to be modified along with the nonlinear frequency analysis, and the stability criterion for the equation under consideration is obtained. On the other hand, the linearized stability theory is employed in the autonomous arrangement. Consequently, the phase portraits around the equilibrium points are sketched. For the non-autonomous organization, the stability criteria are analyzed via the multiple time scales technique. Numerical estimations are designed to confirm graphically the analytical approximate solutions as well as the stability configuration. It is revealed that the exciting external force parameter plays a destabilizing role. Furthermore, both of the frequency of the excited force and the stiffness parameter, execute a dual role in the stability picture.
No abstract is provided for this article.
Many architectural systems are modelled by boundary value problems. Though there are many numerical and analytical methods to solve such problems, this paper suggests a simple but effective way to the third-order ordinary differential equations by the Taylor series technology. The governing equation is differentiated to obtain high order derivatives of a certain point, and solution is expanded into a Taylor series of the point, the boundary conditions are then used to identify the unknowns involved in the approximate solution. An example is given to elucidate the solution process, the maximal error is less 2%, and its accuracy can be further improved if a higher order series is solved. The approximate solution is compared with that by the variational iteration method, showing the present method is simpler and more straightforward. The comparison with the numerical solution culminates in its reliability and effectiveness. The method can be extended to fractal calculus.
Article Semi-Inverse Method of Establishing Generalized Variational Principles for Fluid Mechanics With Emphasis on Turbomachinery Aerodynamics was published on March 1, 1997 in the journal International Journal of Turbo & Jet-Engines (volume 14, issue 1).
Periodic behavior analysis of nano/microelectromechanical systems (N/MEMS) is an essential field owing to their many promising applications in microinstruments. The interesting and unique properties of these systems, particularly, small size, batch fabrication, low power consumption, and high reliability, have fascinated researchers and industries to implement these structures for the production of different microdevices. The dynamic oscillatory behavior of N/MEMS is very intricate due to the various types of nonlinearities present in these structures. The foremost objective of this study is to explore the periodicity of oscillatory problems from N/MEMS. The variational iteration method (VIM), which has been considered as an effective approach for nonlinear oscillators, is coupled with the Laplace transform to obtain the approximate analytic solution of these nonlinear vibratory systems with fewer computations. This coupling of VIM and Laplace transform not only helps in the identification of the Lagrange multiplier without getting into the details of the cryptic theory of variations, but also finds the frequency-amplitude relationship and the analytic approximate solution of N/MEMS. A generalized vibratory equation for N/MEMS is followed by three examples as special cases of this generalized equation are given to elucidate the effectivity of the coupling. The solution obtained from the Laplace-based VIM not only exhibits good agreement with observations numerically but also higher accuracy yields when compared to other established techniques in the open literature.
A new fractal derive is defined, which is very easy for engineering applications to discontinuous problems, two simple examples are given to elucidate to establish governing equations with fractal derive and how to solve such equations, respectively.
No abstract is provided for this article.
Nanopore on a surface (e.g. the epidermis of a leaf) can absorb nanoparticles, and nanoparticles on a surface play a contrary role. Comparison of wild silk with Bombyx mori silk reveals that the former has obvious nanoparticle-like crystals, which can repel water or dust, resulting in waterproof and dustproof of wild silk.
A variety of nonlinear differential models exist for reaction kinetics. Although exact or approximate solutions might not be the main focus in practical applications, the slope at a specific point holds great physical significance and an accurate estimate is crucial. This paper introduces two novel concepts: the point solution and the point slope. These are based on the idea that the accuracy of a particular point is notably higher than that of other points within the solution domain. The paper uses non-Michaelis-Menten kinetics as an example to explain the methodology for obtaining an accurate point slope for the amperometric current response. Moreover, the main factors influencing the response are clearly shown through a closed and simple mathematical formulation. The effectiveness and advantages of this technique are demonstrated by comparing the results with those in existing literature. For the chemistry field to leverage the potential of this approach, this article can serve as a model for practical applications.
Why do more complex viruses (e.g., HIV, AIDS-virus and SARS coronavirus) tend to be more fatal? The paper concludes that the cell fractal geometry of viruses is the key. This paper also suggests two possible new approaches using nanotechnology and temperature to cure or prevent virus infection.
No abstract is provided for this article.
Neglected diseases boost (Nature, 457: 772, 2009), that will become greater threat to human health especially in tropical regions. In my opinion, it is the inherent result of climate warming. An allometrical scaling is suggested to support my opinion, this can also explain why swine flu does not affect pigs very much, but human beings fatally. Key words: Global climate change, disease, temperature, allometrical scaling, swine flu, HIV, H1N1, virus.
This paper points out that the so called enhanced variational iteration method (Colantoni & Boubaker, 2014) for a nonlinear equation arising in electrospinning and vibration-electrospinning process is the standard variational iteration method. An effective algorithm using the variational iteration algorithm-II is suggested for Bratu-like equation arising in electrospinning. A suitable choice of initial guess results in a relatively accurate solution by one or few iteration.
