The present paper focuses on the nature of the different interactions between cometary nucleus and tail with solar wind. The dynamics of the comet will impose many features that provide unique behavior of the comet when entering the solar system. These features are reviewed in this paper and few investigations are made. The calculations made in this work represent the analysis and interpretation of the different features of the comet, such as perihelion and eccentricity dependence on the gas production rate, and the dependence of the latter on the composition of the comet nucleus. The dependences of the heliocentric, bow shock, contact surface, and stand-off distances with gas production rate for many types of comets that cover linear and n

The main purpose of this paper, is to introduce a topological space , which is induced by reflexive graph and tolerance graph , such that  may be infinite. Furthermore, we offered some properties of  such as connectedness, compactness, Lindelöf and separate properties. We also study the concept of approximation spaces and get the sufficient and necessary condition that topological space is approximation spaces.

High performance work systems and general industrial enterprise performance

The current study aims to identify agreeableness and orientation towards voluntary work of officials in public facilities, as well as to identify the nature of the correlation between agreeableness and orientation towards voluntary work of officials in public facilities. To achieve the aims of the research, the researchers designed the agreeableness scale, which consists of (28) items in its final form. The researchers also built a scale of orientation towards voluntary work, which consists of (29) items in its final form. Psychometric properties of validity and reliability of the two scales were extracted in various ways. The researcher applied the two scales on a sample of (400) officials, the results indicated that the

In this paper, the problem of scheduling jobs on one machine for a variety multicriteria
are considered to minimize total completion time and maximum late work. A set of n
independent jobs has to be scheduled on a single machine that is continuously available from
time zero onwards and that can handle no more than one job at a time. Job i,(i=1,…,n)
requires processing during a given positive uninterrupted time pi, and its due date d
i.
For the bicriteria problems, some algorithms are proposed to find efficient (Pareto)
solutions for simultaneous case. Also for the multicriteria problem we proposed general
algorithms which gives efficient solutions within the efficient range

The phenomenon of spatial variation in the economic, social and urban development levels is considered prevalent in most of the economic and social systems,this relates to the concentration of most of those activities in certain regions and because of their rarity in other regions , that led to the emergence of the problem of the sharp contrast between the most developed areas and least developed areas within the same region or within the regions of the same country,
Reduction of this variables , in addition to the development of areas through following up and relying on an effective regional development enabling to reduce unemployment as well as to stop the migration of the unplanned for population,
And the ideal use of available

The research aims to find the impact of a proposed strategy according to the Luria model on realistic thinking among fifth-class scientific students and their achievement in mathematics. To achieve it, the experimental research method and the quasi-experimental design were used for two equal groups, one of them is a control group taught in traditional way and the other is an experimental one taught according to strategy based on Luria model. The research community represents the students of the fifth scientific class from the General Directorate of Education of Karkh First. The research sample (40) students were deliberately chosen and distributed equally between the two groups after making sure that they were equals in their previo

This study aims to design unified  electronic information system to manage students attendance in Lebanese French university/Erbil, as a system that simplifies the process of entering and counting the students absence, and generate absence reports to expel students who passed  the acceptable limit of being absent, and by that we can replace the traditional way of  using papers to count absence,  with  a complete electronically system for managing students attendance, in a way that makes the results accurate and unchangeable by the students.

            In order to achieve the study's objectives, we designed an information syst

The contemporary role of administrative accounting Renewal or threat

Mental systems in ontological discourse turned into deliberative systems, derived from the non-coordinated thought that motivated ontological discourse, as an incomplete thought, after it became close to reason; Between creation and prevention, between reasoning and creation, between submission and ambition, the result of an interconnected entity that slays one another from one another, and intersects with one another, to produce a special pattern each time, completely different from its predecessor or to provide a path for the coordination of others, which is outside the linguistic event, or part From it, signs and marks, produced to a large extent M., and united the signs; to return again in a circular and rotational movement to produc