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THE EVOLUTION OF PLANETARY NEBULAE(PN) AND FADING TIME ACCORDING TO SYNTHETIC MODEL
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Abstract Planetary nebulae (PN) represents the short phase in the life of stars with masses (0.89-7) M☉. Several physical processes taking place during the red giant phase of low and intermediates-mass stars. These processes include :1) The regular (early ) wind and the envelope ejection, 2) The thermal pulses during Asymptotic Giant Branch (AGB ) phase. In this paper it is briefly discussed how such processes affect the mass range of Planetary Nebulae(PN) nuclei(core) and their evolution, and the PN life time, and fading time for the masses which adopted. The Synthetic model is adopted. The envelope mass of star (MeN ) and transition time (ttr) calculated respectively for the parameter (MeR =1.5,2, 3×10-3 M☉). Another time scale is of capital importance for the understanding of PN and their nuclei, it is the fading time ( tf). The results indicated that for each observed nebulae( ttr < tPN) also the fading time is sensitive to mass core(MH) of star, the mass with 1.2 M☉ takes only (25 yr ) to fading, while the mass with (0.66 M☉) takes about ( 4715 yr) years to fading. The calculations showed that (ttr) increases with the increasing of final mass( Mf). The initial nebulae radius will also increase with (Mf) thus will correlate with the location of nucleus on the HR diagram.

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Publication Date
Sun Mar 07 2010
Journal Name
Baghdad Science Journal
Study the Level of Service to Roadways which Leading to Basrah University
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The building of Basrah University located in a rural area at Gramat Ali, its consist of seven colleges and very high number of students, lecturers ,and employers. Therefore, the intersections which leading to university building suffer congestion at morning peak hour (8-9) A.M and evening peak hour (2-3) P.M. In this study we collected the data in intersections which leading to university building at peak hour at same time, then we had analysis this data by using the highway capacity manual (HCM) and program (HCS). Also, we collected that data in University entries with classification of vehicles according to types and number of passengers at peak hour. Then we studied the number of proposals to riddance the congestion, such as the effe

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Publication Date
Mon Oct 01 2012
Journal Name
Al–bahith Al–a'alami
Skills of Media Marketing of the Public Relations Staff: (University of Baghdad as a Model)
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Departments and offices of public relations and media in any institution or company is the most important departments that reflect the results of their work negatively or positively on their reputation. This goes beyond the trust and credibility that its internal and external audiences will give it. Where such matter requires the staff, working in these departments and offices, to have communication skills that qualify them to do the role of marketing the communication message. Yet, the communication skills of public relations and media staff vary from person to person depending on the communication position. This skill has two criteria: Achieving the communication goal and the speed in achieving it as a number of skills

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Publication Date
Tue Jun 24 2025
Journal Name
Misan Journal Of Academic Studies
Some of Parametric and Non Parametric Estimations for Circular Regression Model via Simulation
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Circular data (circular sightings) are periodic data and are measured on the unit's circle by radian or grades. They are fundamentally different from those linear data compatible with the mathematical representation of the usual linear regression model due to their cyclical nature. Circular data originate in a wide variety of fields of scientific, medical, economic and social life. One of the most important statistical methods that represents this data, and there are several methods of estimating angular regression, including teachers and non-educationalists, so the letter included the use of three models of angular regression, two of which are teaching models and one of which is a model of educators. ) (DM) (MLE) and circular shrinkage mod

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Publication Date
Sun Nov 15 2020
Journal Name
Journal Of Petroleum Research And Studies
Reservoir Model and Production Strategy of Mishrif Reservoir-Nasryia Oil Field Southern Iraq
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Nasryia oil field is located about 38 Km to the north-west of Nasryia city. The field was discovered in 1975 after doing seismic by Iraqi national oil company. Mishrif formation is a carbonate rock (Limestone and Dolomite) and its thickness reach to 170m. The main reservoir is the lower Mishrif (MB) layer which has medium permeability (3.5-100) md and good porosity (10-25) %. Form well logging interpretation, it has been confirmed the rock type of Mishrif formation as carbonate rock. A ten meter shale layer is separating the MA from MB layer. Environmental corrections had been applied on well logs to use the corrected one in the analysis. The combination of Neutron-Density porosity has been chosen for interpretation as it is c

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Publication Date
Tue Feb 27 2024
Journal Name
Mathematical Modelling Of Engineering Problems
Dynamics of a Fractional-Order Prey-Predator Model with Fear Effect and Harvesting
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Publication Date
Mon Jun 10 2024
Journal Name
Iraqi Journal For Computer Science And Mathematics
Solving tri-criteria: total completion time, total late work, and maximum earliness by using exact, and heuristic methods on single machine scheduling problem
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The presented study investigated the scheduling regarding  jobs on a single machine. Each  job will be processed with no interruptions and becomes available for the processing at time 0. The aim is finding a processing order with regard to jobs, minimizing total completion time , total late work , and maximal tardiness  which is an NP-hard problem. In the theoretical part of the present work, the mathematical formula for the examined problem will be presented, and a sub-problem of the original problem of minimizing the multi-objective functions  is introduced. Also, then the importance regarding the dominance rule (DR) that could be applied to the problem to improve good solutions will be shown. While in the practical part, two

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Publication Date
Tue Mar 26 2024
Journal Name
World Electric Vehicle Journal
Fast Finite-Time Composite Controller for Vehicle Steer-by-Wire Systems with Communication Delays
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The modern steer-by-wire (SBW) systems represent a revolutionary departure from traditional automotive designs, replacing mechanical linkages with electronic control mechanisms. However, the integration of such cutting-edge technologies is not without its challenges, and one critical aspect that demands thorough consideration is the presence of nonlinear dynamics and communication network time delays. Therefore, to handle the tracking error caused by the challenge of time delays and to overcome the parameter uncertainties and external perturbations, a robust fast finite-time composite controller (FFTCC) is proposed for improving the performance and safety of the SBW systems in the present article. By lumping the uncertainties, parameter var

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Publication Date
Mon Dec 20 2021
Journal Name
Baghdad Science Journal
Crucial File Selection Strategy (CFSS) for Enhanced Download Response Time in Cloud Replication Environments
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Cloud Computing is a mass platform to serve high volume data from multi-devices and numerous technologies. Cloud tenants have a high demand to access their data faster without any disruptions. Therefore, cloud providers are struggling to ensure every individual data is secured and always accessible. Hence, an appropriate replication strategy capable of selecting essential data is required in cloud replication environments as the solution. This paper proposed a Crucial File Selection Strategy (CFSS) to address poor response time in a cloud replication environment. A cloud simulator called CloudSim is used to conduct the necessary experiments, and results are presented to evidence the enhancement on replication performance. The obtained an

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Publication Date
Mon Dec 19 2022
Journal Name
Drones
Practically Robust Fixed-Time Convergent Sliding Mode Control for Underactuated Aerial Flexible JointRobots Manipulators
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The control of an aerial flexible joint robot (FJR) manipulator system with underactuation is a difficult task due to unavoidable factors, including, coupling, underactuation, nonlinearities, unmodeled uncertainties, and unpredictable external disturbances. To mitigate those issues, a new robust fixed-time sliding mode control (FxTSMC) is proposed by using a fixed-time sliding mode observer (FxTSMO) for the trajectory tracking problem of the FJR attached to the drones system. First, the underactuated FJR is comprehensively modeled and converted to a canonical model by employing two state transformations for ease of the control design. Then, based on the availability of the measured states, a cascaded FxTSMO (CFxTSMO) is constructed to estim

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Publication Date
Mon Mar 13 2017
Journal Name
Journal Of Baghdad College Of Dentistry
White Spot Lesions Among Patients Treated With Fixed Orthodontic Appliance at Different Time Intervals
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ABSTRACT Background:- White spot lesions are common esthetic problem that compromise the success of orthodontic treatment. This study aimed to assess white spot lesions in patients with fixed orthodontic appliance at different time intervals. Materials & Methods:- Thirty two patients (24 females and 8 males) were included in this study and they underwent clinical examination for white spot lesions using enamel decalcification index at four time intervals: (2-3 weeks after appliance insertion, 2, 4 and 6 months). Results:- The patients were free of white spot lesions at the appliance insertion visit. The mean of white spot lesions was 2.22 which were increased significantly during six months to reach 24.59 at the end of study. There was a si

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