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Electromagnetic transient modeling of form-wound stator coils with stress grading system under PWM excitation

The insulation system of a machine coil includes several layers made of materials with different characteristics. The effective insulation design of machine coils, especially in the machine end winding, depends upon an accurate model of the stress grading system. This paper proposes a modeling approach to predict the transient overvoltage, electric field, and heat generation in machine coils with a stress grading system, considering the variation of physical properties in the insulation layers. A non-uniform line model is used to divide the coil in different segments based on material properties and lengths: overhang, stress grading and slot. The cascaded connection of chain matrices is used to connect segments for the representation of the complete machine coil. The resulting model is able to simulate the transient overvoltages due to the application of fast rise time pulses such as those observed with pulse width modulation from adjustable speed drives, considering coils with different insulation topologies and under pulses with different rise times. The parameters in each coil region are calculated using the finite element method (FEM). Additionally, the resistive heat and electric field distribution in the machine coil are calculated for excitations with different rise times by means of 3-dimensional FEM simulations.

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Publication Date
Wed Feb 08 2023
Journal Name
Iraqi Journal Of Science
Bioremoval of Chromium by Local Isolates of Pseudomonas aeruginosa in Respect to its Genotype

The current study included bioremoval of chromium metal ions from aqueous solution by using seventeen Pseudomonas aeruginosa species isolated from different environments. The experimental results showed that isolates Pseudomonas aeruginosa have high efficiency in removal of chromium where the P. aeruginosa p.8 was the most efficient (P≥0.001) in bioremoval of chromium with a removal capacity reached 92.5 mg/L and removal index reached (96.5%). While P. aeruginosa p.4 was the least efficient (P≥0.001) in bioremoval of chromium from aqueous solutions reached 74.6 mg/L and removal index reached (79.8%). The REP-PCR detection using BOX-primer, showed genetic relatedness among the isolates of P.aeru

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Publication Date
Wed Dec 01 2021
Journal Name
Iraqi Journal Of Physics
Effect of Silver Nanoparticles on Fluorescence Intensity of Fluoreseina Dye Mixed in One Solution

Metal enhanced fluorescence (MEF) is an unequaled phenomenon of metal nanoparticle surface plasmons, when light interacts with the metal nanostructures (silver nanoparticles) which result electromagnetic fields to promote the sensitivity of fluorescence. This work endeavor to study the influence of silver nanoparticles on fluorescence intensity of Fluoreseina dye by employment mixture solution with different mixing ratio. Silver nanoparticles had been manufactured by the chemical reduction method so that Ag NP layer coating had been done by hot rotation liquid method. The optical properties of the prepared samples (mixture solution of Fluoreseina dye solutions and colloidal solution with 5 minutes prepared of Ag NPs) tested by using UV-V

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Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
New vision of Mr. Abdul Mahdi Al-Muttafiqi in the light of unpublished documents

New vision of Mr. Abdul Mahdi Al-Muttafiqi in the light of unpublished documents

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Publication Date
Tue Nov 19 2024
Journal Name
Journal Of Physical Education
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Publication Date
Tue Nov 19 2024
Journal Name
Webology
Is the Stealth Marketing an Element of Promotion Mix? A Review of the Techniques

Stealth marketing is considered as one of the contemporary issues that researchers have begun to explore as a current understanding. It is the marketing approach used by organizations to promote their products and services to the public in implicit and indirect manner. In this article, the concept of stealth marketing will be discussed throw its advantages and disadvantages. In addition, the different techniques of stealth marketing have been discussed including: viral marketing, celebrity marketing, brand pushers, bait-and-tease marketing, video games marketing, and marketing in music. Furthermore, a new technique of marketing entitled “Marketing through social responsibility” has been added and discussed according to the themes in the

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Publication Date
Wed Jun 07 2023
Journal Name
Journal Of Educational And Psychological Researches
Building a Training Program in the development of the Willpower of the Kindergarten Children

The research aims to build a training program to develop the willpower in the kindergarten children. In order to achieve the objective of the research, the two researchers have developed a Training Program according to the following steps:

- Determining the general objective of the Training Program.

- Determining the behavioral objectives of the Training Program.

- Determining the content of the Training Program.

- Implementing the content of the Training Program sessions.

- Evaluating the Training Program.

The training program consisted of (15) sessions, each session included a set of parts (title, general objective, methods, time and place to implement the sessions, behavioral goals, tool

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Publication Date
Tue Feb 13 2024
Journal Name
Iraqi Journal Of Science
A Study on the Bases of Space of Vector Valued Entire Multiple Dirichlet Series

Let 


 
, 1
( )
1 2 ,
( , ) 1 2
m n
s s
m n
f s s a e m n   , (s   it , j 1,2) j j j  ,  
m 1  and
 
n 1  being an increasing sequences of positive numbers and a E m n  , where E
is Banach algebra, represent a vector valued entire Dirichlet functions in two
variables. The space  of all such entire functions having order at most equal to 
is considered in this paper. A metric topology using the growth parameters of f is
defined on  and its various properties are obtained. The form of linear operator on
the space  is characterized and proper bases are also characterized in terms of
growth parameters  .

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Publication Date
Tue Sep 19 2017
Journal Name
Al-academy
Peer Education Strategy and its Impact on the Development of Skill of Perspective Drawing

       After the twenty – first century become  necessary for us motorcade era in educational a chevements by searching  for the best  strategies and teaching methods and  techniques  artotalbagesh  resorting to the strategy

Did not use in use in the teaching of the foreseeable  material  general by voice and teaching  perspective  for the student of the class fourth science

In particular ,so the researcher asking the question follows:

Can the peer education strategy to have an impact in perspective drawing skill development ?

   From here it demonstrated the importance of current research know the impact of  p

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Publication Date
Sun Jan 30 2022
Journal Name
Iraqi Journal Of Science
Influence of Heat Treatment on Wear and Hardness Properties of MWCNTs Reinforced Epoxy nanocomposites

Nanocomposite of carbon nanotube add to epoxy resin material of weight fraction ( 0.25, 0.5, 0.75 1.0, 1.25, 1.5, 1.75 , 2 & 2.5 wt. % ) were fabricated by dispersing within an epoxy resin using a Ultrasound machine followed by mechanical stirring. The samples were heat treated at temperature ( 80 °C for 3 hrs) The mechanical properties of the composites were investigated. Wear and hardness properties measurements indicated higher wear rate and hardness with increasing concentration of MWCNTs . The MWCNTs significantly improved the wear resistance and hardness when compare than the pure epoxy. These note show too after heat treatment of composite with ( 80 oC for 3 hrs ).

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Publication Date
Sat Jun 27 2020
Journal Name
Iraqi Journal Of Science
On Analytical Solution of Time-Fractional Type Model of the Fisher’s Equation

In this paper, the time-fractional Fisher’s equation (TFFE) is considered to exam the analytical solution using the Laplace q-Homotopy analysis method (Lq-HAM)”. The Lq-HAM is a combined form of q-homotopy analysis method (q-HAM) and Laplace transform. The aim of utilizing the Laplace transform is to outdo the shortage that is mainly caused by unfulfilled conditions in the other analytical methods. The results show that the analytical solution converges very rapidly to the exact solution.

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