In this work, we consider a modification of the Lotka-Volterra food chain model of three species, each of them is growing logistically. We found that the model has eight equilibrium points, four of them always exist, while the rest exist under certain conditions. In terms of stability, we found that the system has five unstable equilibrium points, while the rest points are locally asymptotically stable under certain satisfying conditions. Finally, we provide an example to support the theoretical results.
The soft sets were known since 1999, and because of their wide applications and their great flexibility to solve the problems, we used these concepts to define new types of soft limit points, that we called soft turning points.Finally, we used these points to define new types of soft separation axioms and we study their properties.
Water harvesting techniques developed globally during the last decades with highly increasing water crisis and climate changes. The Yeoman keyline method was spread widely with increased use for sustainable permaculture development. The main aim of the current study is to analyze and solve the siltation problem in Dwerige weir and to develop water resources in the basin area. The remote sensing data, field surveying, and hydrology are used together to build a new geotechnical approach. The results show that a huge siltation quantity was not considered in the weir design studies, which were represented by sand sheet materials and eroded soils washed by flooding and entering the weir reservoir through four main channels. The t
... Show MoreAtmospheric stability plays the most important role in the transport and dispersion of air pollutants. Different methods are used for stability determination with varying degrees of complexity. Most of these methods are based on the relative magnitude of convective and mechanical turbulence in atmospheric motions, such as Richardson number, Monin-Obukhov length, Pasquill-Gifford stability classification and Pasquill-Turner stability classification. The Pasquill-Turner Method (PTM), which is employed in this study used Observations of wind speed, solar altitude angle and the time of day to classify atmospheric stability with distinguishable indices. As a case study, meteorological data that gathered from European Centre For Medium-Range W
... Show MoreThe issue of peaceful coexistence between societies is the topic of the hour, as it is one of the important issues in this era, especially in days when conflicts and conflicts abound, and even wars in the name of religion, gender, race, language, and the like. The world, so that single-mindedness and adherence to one opinion and intolerance to it became the method of dialogue in our world today, as writing in the field of peaceful coexistence, peace-building, tolerance, pluralism, and acceptance of the other is one of the new fields of knowledge in Iraq in general and in Nineveh Governorate in particular, as peaceful coexistence is one of the basic needs And necessary for the presence of individuals in societies, and it requires the achi
... Show MoreThe rotor dynamics generally deals with vibration of rotating structures. For designing rotors of a high speeds, basically its important to take into account the rotor dynamics characteristics. The modeling features for rotor and bearings support flexibility are described in this paper, by taking these characteristics of rotor dynamics features into standard Finite Element Approach (FEA) model. Transient and harmonic analysis procedures have been found by ANSYS, the idea has been presented to deal with critical speed calculation. This papers shows how elements BEAM188 and COMBI214 are used to represent the shaft and bearings, the dynamic stiffness and damping coefficients of journal bearings as a matrices have been found
... Show MoreThe current research aimed to identify psychological stability and its relationship to university integration and spiritual intelligence among university students. The research sample consisted of (158) students from the College of Education - Al-Mustansiriya University.
A scale was applied: psychological stability, university integration, and spiritual intelligence, and by using the (Pearson) correlation coefficient, and the t-test, the results showed: the sample members enjoy psychological stability, university integration, and spiritual intelligence, and there is a positive, statistically significant correlation between the research variables, and the results resulted in some recommendations and proposals.
Field studies of the slopes of Bammo anticline, in Northeast of Iraq, was carried out in five selects stations, where rock slopes and the discontinuities were surveyed in these stations and its relationships with failures were determined. The field work was revealed the abundance of rock slope failures, the dominant types are rock fall and toppling.
Slope stabili
... Show MoreIn this work, new di-acid monomers 4, 4’-di-carboxillic-4â€-bromo-2â€, 6â€-dimethyl triphenylamine (Ma), 4, 4’- di-carboxylic -4â€-chloro-2â€, 6â€-dimethyl triphenylamine (Mb) and 4, 4’- di-carboxylic -2â€,4â€-dichloro-6â€-methyl triphenylamine (Mc) were synthesized by reaction of p-cyanobenzofluride with three different aromatic amines (4-bromo,2,6-dimethyl aniline, 4-chloro,2,6-dimethyl aniline and 2,4 dichloro, 6- methyl aniline ) via aromatic nucleophilc substitution method to form three di cyano intermediates 4, 4’-Dicyano-4â€-bromo-2â€, 6â€-dimethyl triphenylamine (Da), 4,
... Show MoreRutting is a crucial element of the mechanical performance characteristics of asphalt mixtures, which was the primary target of this study. The task involved substituting various portions of virgin coarse aggregate with recycled concrete aggregate materials that had been treated or left untreated at rates ranging from 25 to 100%, with a constant increase of 25%. The treatment process of recycled concrete aggregate involved soaking in acetic acid, followed by a mechanical process for a short time inside a Los Angeles machine without the balls. This research utilized two primary tests: the standard Marshall test to identify the optimal asphalt contents and the volumetric characteristics of asphalt mixtures. The other one w
... Show MoreRegression Discontinuity (RD) means a study that exposes a definite group to the effect of a treatment. The uniqueness of this design lies in classifying the study population into two groups based on a specific threshold limit or regression point, and this point is determined in advance according to the terms of the study and its requirements. Thus , thinking was focused on finding a solution to the issue of workers retirement and trying to propose a scenario to attract the idea of granting an end-of-service reward to fill the gap ( discontinuity point) if it had not been granted. The regression discontinuity method has been used to study and to estimate the effect of the end -service reward on the cutoff of insured workers as well as t
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