A numerical method for the calculation of the three-dimensional wake rollup behind symmetric wings with ground effect and its aerodynamic characteristics for steady low subsonic flow have been developed. A non-planar quadrilateral vortex-ring method with vortex wake relaxation iterative scheme for lifting surfaces is obtained. A computer program was build to treat wings with breaks, span wise trailing edge flaps, local dihedral angle, camber, twist and ground effect. Forces and moments are obtained from vector product of local velocity and vortex strength multiplied by density. The program has been validated for a number of configurations for which experimental data is available. Good agreement has been obtained for these configurations. Also many results obtained for different cases of wing with different shapes parameters.
The polymeric hydrogels composed of poly vinyl alcohol (m.wt 72000) and glutaraldehyde(5%,8% and 10%) , have been thermally prepared for the purpose of studying their swelling and drug release behavior . The swelling ratio was measured for all the hydrogel samples at 37°C, in three different media pH (1.2, 4.7 and 6.8) as a function of time. The results show that the maximum swelling ratios were arranged as follows :pH =6.8 > pH =4.7 > pH =1.2 hydrogels cross linked PVA showed a typical pH responsive behavior such as high pH has maximum swelling while low pH shows minimum swelling.
Abstract: In this research, nanofibers have been prepared by using an electrospinning method. Three types of polymer (PVA, VC, PMMA) have been used with different concentration. The applied voltage and the gap length were changed. It was observed that VC is the best polymer than the other types of polymers.
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In this paper, new concepts which are called: left derivations and generalized left derivations in nearrings have been defined. Furthermore, the commutativity of the 3-prime near-ring which involves some
algebraic identities on generalized left derivation has been studied.
In this research a new system identification algorithm is presented for obtaining an optimal set of mathematical models for system with perturbed coefficients, then this algorithm is applied practically by an “On Line System Identification Circuit”, based on real time speed response data of a permanent magnet DC motor. Such set of mathematical models represents the physical plant against all variation which may exist in its parameters, and forms a strong mathematical foundation for stability and performance analysis in control theory problems.
This paper is concerned with the oscillation of all solutions of the n-th order delay differential equation . The necessary and sufficient conditions for oscillatory solutions are obtained and other conditions for nonoscillatory solution to converge to zero are established.
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In this research, nanofibers have been prepared by using an electrospinning method. Three types of polymer (PVA, VC, PMMA) have been used with different concentration. The applied voltage and the gap length were changed. It was observed that VC is the best polymer than the other types of polymers.
Let L be a commutative ring with identity and let W be a unitary left L- module. A submodule D of an L- module W is called s- closed submodule denoted by D ≤sc W, if D has no proper s- essential extension in W, that is , whenever D ≤ W such that D ≤se H≤ W, then D = H. In this paper, we study modules which satisfies the ascending chain conditions (ACC) and descending chain conditions (DCC) on this kind of submodules.