Nonlinear differential equation stability is a very important feature of applied mathematics, as it has a wide variety of applications in both practical and physical life problems. The major object of the manuscript is to discuss and apply several techniques using modify the Krasovskii's method and the modify variable gradient method which are used to check the stability for some kinds of linear or nonlinear differential equations. Lyapunov function is constructed using the variable gradient method and Krasovskii’s method to estimate the stability of nonlinear systems. If the function of Lyapunov is positive, it implies that the nonlinear system is asymptotically stable. For the nonlinear systems, stability is still difficult even though the Lyapunov methods are applied. There has to find a positive definite Lyapunov function, and its derivative function has to be negative definite. A new approach had been tested in several …
Different parameters of double pipe helical coil were investigation experimentally. Four coils were used; three with a curvature ratio (0.037, 0.031, and 0.028) and 11mm diameter of the inner tube while the fourth with 0.033 curvature ratio and 13 mm diameter of the inner tube. The hot water flow in the inner tube whereas the cold water flows in the annulus. The inlet temperatures of hot and cold water are 50 0C and 18 0C respectively. The inner mass flow rate ranges from 0.0167 to 0.0583 kg/s. The results show the Nusselt number increase with increase curvature ratio. The Nusselt number of the coil with 0.037 curvature ratio increases by approximately 12.3 % as compare with 0.028 curvature ratio. The results also r
... Show MoreThe aim of the research is to know the level of mental motivation among students of the Arabic language departments in the Faculties of Education in the universities of Baghdad Governorate and its relationship to their attitudes towards the profession, and the level of orientation towards the profession among students of the Arabic language departments in the Faculties of Education. And the correlational relationship between mental motivation and career orientation among students of Arabic language departments in the Faculties of Education, and the current research is determined by students of Arabic language departments in the Faculties of Education and the universities (Education Ibn Rushd- University of Baghdad, Education-  
... Show MoreThis study was conducted to test the effectiveness of Agaricus bisporus inoculums (spawn) in the ratio of (0.25, 0.5 and 1%) v/v to control Pythium aphanidermatum fungus the causal agent of damping- off disease of cucumber plant. results showed the ability of A. bisporus fungus to protect the seedlings from incidence by P. aphanidermatum . all treatments of edible fungus inoculums were significantly different from pathogen treatment after 15 day of planting and there was no significant difference found from control treatment (without pathogen) . the successful of A. bisporus was continued to protect the seedlings after 30 and 45 day after planting. The numbers of seedlings were (8, 7.25 & 7.25) respectively compared to 5.5 seedlings in con
... Show MoreStart your abstract here the objective of this paper is to study the dynamical behaviour of an eco-epidemiological system. A prey-predator model involving infectious disease with refuge for prey population only, the (SI_) infectious disease is transmitted directly, within the prey species from external sources of the environment as well as, through direct contact between susceptible and infected individuals. Linear type of incidence rate is used to describe the transmission of infectious disease. While Holling type II of functional responses are adopted to describe the predation process of the susceptible and infected predator respectively. This model is represented mathematically by
?Natural Occurrence of aflatoxin Bi and B2 was investigated monthly in paddy rice stored for duration of six months. Aflatoxin B| was detected at the beginning of storage. The concentration of aflatoxin Bi in paddy and polished rice was found to be (0.3 and ()) ppb respectively while aflatoxin B2 W'as not detected in both paddy and polished rice afler six months of storage, concentration of aflatoxin Bi ‘ ’ ' reached 3 ppb in paddy rice and 0.9 ppb in polished rice, while the study proved that the concentration of aflatoxin in paddy rice was higher than polished rice as a result of processing which reduce the toxin
The current research aims to test the relationship of the impact of sustainable leadership as an independent variable in organizational happiness as a dependent variable, in the departments and divisions of the Tourism Authority, to come up with a set of recommendations that contribute to raising the level of organizational happiness in the authority. And based on the importance of the research topic in the General Authority, and the prominent role that this body plays in society, the researcher adopted the descriptive and analytical approach in carrying out this research, by collecting data from the departments and divisions staff of (160) respondents in an exclusively comprehensive
... Show MoreA polycrystalline PbxS1-x alloys with various Pb content ( 0.54 and 0.55) has been prepared successfully. The structure and composition of alloys are determined by X-ray diffraction (XRD), atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF) respectively. The X-ray diffraction results shows that the structure is polycrystalline with cubic structure, and there are strong peaks at the direction (200) and (111), the grain size varies between 20 and 82 nm. From AAS and XRF result, the concentrations of Pb content for these alloys were determined. The results show high accuracy and very close to the theoretical values. A photoconductive detector as a bulk has been fabricated by taking pieces of prepared alloys and polished chemic
... Show MoreBackground: Saliva is a specific bio-fluid with important biomarkers. Analyzing any alternation in these markers could give valuable information, in relation to oral health status parameters. The aim of this study was to investigate the level of α -amylase in unstimulated whole saliva of healthy, primary school children in relation to some oral health parameters. Materials and Methods: A questionnaires consisted of demography and medical histories of participants were filled by children families. Saliva samples were collected for 5- minutes between 9:00 -11:00 AM from 114 healthy students aged 6-13 years, divided into four age groups. Flow- rate, Plaque and Gingival Index were assessed and dentition status was investigated by DMFT/dmft
... Show MoreKESMM Al, WAA Al-Nuaimy
A localized stenosis or aneurysm is a discontinuity that presents the pulse wave produced by the contracting heart with a reflection site. However, neither wave speed ( c) in these discontinuities nor the size of reflection in relation to the size of the discontinuity has been adequately studied before. Therefore, the aim of this work is to study the propagation of waves traversing flexible tubes in the presence of aneurysm and stenosis in vitro. We manufactured different sized four stenosis and four aneurysm silicone sections, connected one at a time to a flexible ‘mother’ tube, at the inlet of which a single semi-sinusoidal wave was generated. Pressure and velocity were measured simultaneously 25 cm downstream the inlet of th
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