A numerical investigation is adopted for two dimensional thermal analysis of rocket thrust chamber wall (RL10), employing finite difference model with iterative scheme (implemented under relaxation factor of 0.9 for convergence) to compute temperature distribution within thrust chamber  wall (which is composed of Nickel and Copper layers). The analysis is conducted for different boundary conditions: only convection boundary conditions then combined radiation, convection boundary conditions also for  different aspect ratio (AR) of cooling channel. The results show that Utilizing cooling channels of high aspect ratio leads to decrease in temperature variation across thrust chamber wall, while no effects on heat transferred to the

Thermal properties of soils are important in buried structures contact problems. Although laboratory is distinctly advantageous in measuring the thermal conductivity of soil under ideal condition, given the ability to simulate relatively large-scale in place of soil bed, the field thermal conductivity of soil is not yet commonly used in many types of research. The use of only a laboratory experiment to estimate thermal conductivity may be the key reason for overestimation or underestimation it. In this paper, an intensive site investigation including field thermal conductivity tests for six different subsoil strata were performed using a thermal probe method (TLS-100) to systematically understanding the effects of field dry density, water c

Background: Folic acid (vitamin B9) is one of the important vitamins that are necessary for growth and development of the embryo and preventing the occurrence of congenital malformations which are one of the important health problems in the developing countries and the world as it has a direct effect on the affected babies, their families and the community. It affects an estimated 3% of newborns worldwide.Periconceptional supplementation with folic acid (before conception and during the first 12 weeks of pregnancy) was found to decrease many important types of these anomalies. Objectives: The aim of this study is to assess knowledge, attitude and practice of periconceptional use of folic acid in pregnant women who are attending antenatal

This study aims to identify the level of application of blue ocean leadership activities in public organizations and to build a conceptual and cognitive framework around this concept. The study adopted a descriptive-analytical approach, and the research sample consisted of (95) individuals from the senior management working at the center of the Iraqi Ministry of Communications (director general, department manager, section head). The data analysis technique used is structural equation modeling (SEM) and the Statistical Package for the Social Sciences (SPSS). The results indicate that the senior management in the Ministry of Communications is working to adopt the blue ocean leadership style through its activities, but not to the leve

Abstract

The researcher seeks, through different aspects of the search, to reach a set of objective concerning in content creation a clear vision about conceptual and practical dimension of relation and effects between (Leader-Member Exchange, and Organizational Commitment) to construct a framework of a pragmatic model as a solution to research problem and it questions. The theoretical problem is derived basically from the scarcity of Arab studies and researches that deal by study and analyses for such important of The two variables blend. The practical problem depends in deriving from reality of every day work in the Iraqi ministry of defense.

On this basis, a formula of research problem for pur

Briefly the term of cyber security is a bunch of operations and procedures working on insurance and protecting the network, computer devices, the programs and data from attack and from damaging penetration, also from breaking, abstraction and disturbing in spite of the fact that the concept of cyber conflict is got widening. So, the needs arise in the state to secure cyberspace and protect it by several methods to confront the electronic intrusions and threats which is known as cyber security. Countries seek to preserve its national security in particular the United States of America after the events of September 11 ,2001. In addition, the United States follow all ways to take over cyber threats.

        The performance of asphalt concrete pavement has affected by many factors, the temperature is the most important environmental one which has a large effect on the structural behavior of flexible pavement materials. The main cause of premature failure of pavement is the rutting, Due to the viscoelastic nature of the asphalt cement, rutting is more pronounced in hot climate areas because the viscosity of the asphalt binder which is
inversely related to rutting is significantly reduced with the increase in temperature resulting in a more rut susceptible paving mixtures. The objective of this study is to determine the effect of temperatures variations on the permanent deformation parameters (perm