In this paper, a sufficient condition for stability of a system of nonlinear multi-fractional order differential equations on a finite time interval with an illustrative example, has been presented to demonstrate our result. Also, an idea to extend our result on such system on an infinite time interval is suggested.
Degenerate parabolic partial differential equations (PDEs) with vanishing or unbounded leading coefficient make the PDE non-uniformly parabolic, and new theories need to be developed in the context of practical applications of such rather unstudied mathematical models arising in porous media, population dynamics, financial mathematics, etc. With this new challenge in mind, this paper considers investigating newly formulated direct and inverse problems associated with non-uniform parabolic PDEs where the leading space- and time-dependent coefficient is allowed to vanish on a non-empty, but zero measure, kernel set. In the context of inverse analysis, we consider the linear but ill-pose
A new panel method had been developed to account for unsteady nonlinear subsonic flow. Two boundary conditions were used to solve the potential flow about complex configurations of airplanes. Dirichlet boundary condition and Neumann formulation are frequently applied to the configurations that have thick and thin surfaces respectively. Mixed boundary conditions were used in the present work to simulate the connection between thick fuselage and thin wing surfaces. The matrix of linear equations was solved every time step in a marching technique with Kelvin's theorem for the unsteady wake modeling. To make the method closer to the experimental data, a Nonlinear stripe theory which is based on a two-dimensional viscous-inviscid interac
... Show MoreThe investigation of earth dams under significant earthquake loads, such as catastrophic earthquakes, is a critical subject in dynamic evaluation. Damage mitigation and structural performance during an earthquake are crucial considerations for an earthen dam. However, Iraq and its neighbors have experienced frequent earthquake activity, including the 2017 Halabja Earthquake, which may have damaged some existing earth dams, posing a higher risk of severe earthquake-induced damage than a cyclic shock. Therefore, assessing the dam’s safety is crucial for protecting downstream communities and determining the best strategies to prevent slope stability failure in the face of frequent s
Oilwell cementing operations are crucial for drilling and completion, preserving the well's productive life. However, weak and permeable formations pose a high risk of cement slurry loss, leading to failure. Lightweight cement, like foamed cement, is used to avoid these difficulties. This study is focused on creating a range of foamed slurry densities and examining the effect of gas concentration on their rheological properties. The foaming agent and foam stabilizer are tested, and the optimal concentration is determined to be 2% and 0.12%, respectively, by the weight of the cement.
Furthermore, the construction of samples of foam cement with different densities (0.8, 1.0, 1.2, 1.4, and 1.6) g/cc is performed to f
... Show MoreAbstract: The use of indirect, all-ceramic restorations has grown in popularity among dentists. Studies have demonstrated that for indirect ceramic restorations to be effective over time, cement and ceramic must be bonded in a stable manner. Chemical, mechanical, and laser irradiation are among the methods used to precondition ceramic surfaces in order to increase bond strength.The objective of the study: This study was performed to investigate the roughness values and surface topography of lithium disilicate glass-ceramic treated with conventional methods and different Er,Cr:YSGG, and fractional CO2 laser conditioning parameters.Material and methods:<
... Show MoreIn this study was undertaken frish fish such as Bigeye Ilisha megaloptera, Nematalos nasus, Suboor Hilsha ilisha and Carp Cyprinus carpio. they were purchased from local marketes in Basrah, Oil was extracted by a solvent extraction method on low temperature. And the level of oil obtiened about (6.08; 10.72; 13.52 and 5.61)% for Bigeye, Jaffout, Suboor and Carp. the Crud oils were compared with vegetable oil (olive oil) and animal fat (tial fat mutton).
The extracted oil from fresh complete fishs with compared oils intraed on pharmacological system through packed in capsul with and with out garlic`s extract. this system analysis with chemical tests.
Results were analyzed statistically by using the SPSS program with using (CRD)