In this paper, a mathematical model consisting of the two harmful
phytoplankton interacting with a herbivorous zooplankton is proposed and studied.
The existence of all possible equilibrium points is carried out. The dynamical
behaviors of the model system around biologically feasible equilibrium points are
studied. Suitable Lyapunov functions are used to construct the basins of attractions
of those points. Conditions for which the proposed model persists are established.
The occurrence of local bifurcation and a Hopf bifurcation are investigated. Finally,
to confirm our obtained analytical results and specify the vital parameters, numerical
simulations are used for a hypothetical set of parameter values.

This research aims at investigating pupils’ ability in using discourse markers which are identified in the English textbooks of secondary schools. Four texts are chosen from third intermediate class. The four texts are short stories of different topics.                                                  

        This research hypothesizes that there are no statistical significant differences among Iraqi intermediate pupils’ ability in using textual

An experimental study was conducted to determine the performance of a solar electric refrigeration system. The system contained flat photovoltaic solar panel which absorbs the solar energy and convert it to electrical energy, used to run the refrigeration cycle. Two refrigeration cycles with electrical solar panel were used over a period of 12 months, the first one with classical parts known in refrigeration cycle, while the second one introduced heat exchanger which improves the coefficient of performance by saving the consumed energy. The coefficient of performance of these refrigeration cycles with compressor efficiency 85% are 2.102 and 2.57 respectively. The overall efficiency of the two systems are 18.9% and 23.13%.

The Aim of this paper is to investigate numerically the simulation of ice melting in one and two dimension using the cell-centered finite volume method. The mathematical model is based on the heat conduction equation associated with a fixed grid, latent heat source approach. The fully implicit time scheme is selected to represent the time discretization. The ice conductivity is chosen
to be the value of the approximated conductivity at the interface between adjacent ice and water control volumes. The predicted temperature distribution, percentage melt fraction, interface location and its velocity is compared with those obtained from the exact analytical solution. A good agreement is obtained when comparing the numerical results of one

we applied the direct product concept on the notation of intuitionistic fuzzy semi d-ideals of d-algebra with investigation some theorems, and also, we study the notation of direct product of intuitionistic fuzzy topological d-algebra.

            The research discusses the mechanism for analyzing the salary scale in the public sector through an analysis of grades, their stages, occupants and their financial entitlements, and the extent to which the information obtained for their investment in strategic planning, conducting correction and treatment can be used. The salaries of the employees in them, whose number is (1117) employees, to be a field of research, as the salary structure in it for the year 2019 was analyzed by relying on a number of statistical tools in the analysis process, including the arithmetic circles, upper limits, minimum limits and percentage, and with

The common history of Latin America countries may contribute significantly to determine the initial beginnings of these States since the current borders are a reflection and drawing of the borders of Antarctica according to the divisions determined by the behavior of the Portuguese and Spanish colonialism as well as what the Pope originally called for in order to divide property between Spain and Portugal. A later change took place especially after the independence in the first quarter of the 19th century for the majority of those States which is something that imposed special consideration in the analysis and description of each of these States. There are constants and variables in this case where all the States share constants, while t

Academic Buoyancy of High School students at the Distinguished Schools

In the last years, the self-balancing platform has become one of the most common candidates to use in many applications such as flight, biomedical fields, industry. This paper introduced the simulated model of a proposed self-balancing platform that described the self–balancing attitude in (X-axis, Y-axis, or both axis) under the influence of road disturbance. To simulate the self-balanced platform's performance during the tilt, an integration between Solidworks, Simscape, and Simulink toolboxes in MATLAB was used. The platform's dynamic model was drawn in SolidWorks and exported as a STEP file used in the Simscape Multibody environment. The system is controlled using the proportional-integral-deriva