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Physical principles of laser–material interaction regimes for laser machining processes
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Lasers, with their unique characteristics in terms of excellent beam quality, especially directionality and coherency, make them the solution that is key for many processes that require high precision. Lasers have good susceptibility to integrate with automated systems, which provides high flexibility to reach difficult zones. In addition, as a processing tool, a laser can be considered as a contact-free tool of precise tip that became attractive for high precision machining at the micro and nanoscales for different materials. All of the above advantages may be not enough unless the laser technician/engineer has enough knowledge about the mechanism of interaction between the laser light with the processed material. Several sequential phenomena occur when an intense laser beam is incident on the surface of a material. Heating, melting, vaporization and plasma formation are present in the normal interaction of an intense laser beam with matter. This may be followed by additional events such as acoustic and optical emissions, structure shockwaves, thermal effects, structural defects and residual stresses. The process is affected by a lot of variables that can transfer the interaction towards extremely different behavior in terms of colder and fewer side-effect interactions, which yield precise features for the processed material. The most crucial variables are the time scale of interaction and laser wavelength with respect to the properties of the processed material undertaken as well as the laser fluence. The objective of this chapter is to introduce the fundamentals of physical and mathematical concepts of laser and matter interaction and its dependency on different time scale regimes. Interaction with a short and ultra-short laser pulse has attracted a significant amount of interest in industry due to its huge impact in micro-/nanomachining applications.

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Publication Date
Sun Apr 08 2018
Journal Name
Al-khwarizmi Engineering Journal
Physical and Morphological Properties of Hard- Soft Ferrite Functionally Graded Materials
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  Functionally graded materials (FGMs), with ceramic –ceramic constituents are fabricated using powder technology techniques. In this work three different sets of FGMs samples were designed in to 3 layers, 5 layers and 7 layers. The ceramic constituents were represented by hard ferrite (Barium ferrite) and soft ferrite (lithium ferrite). All samples sintered at constant temperature at 1100oC for 2 hrs. and characterized by FESEM. Some physical properties were measured for fabricated FGMs include apparent density, bulk density, porosity, shrinkage and hardness. The results indicated that the density increase with the increase the number of layer. Lateral shrinkage is one of the important parameter f

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Publication Date
Fri Dec 30 2011
Journal Name
Al-kindy College Medical Journal
Excessive crying in infancy; value of the history and physical examination
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Background: Excessive crying in early
infancy is a common condition that causes a
great deal of concern to the parents and
physician.
Objective: The aim of this study is to find
the underlying etiology of excessive crying in
infancy and to determine how the history,
physical examination, and laboratory
investigations contribute to the final diagnosis.
Method: A prospective study done on 150
afebrile infants less than 4 months of age
visited Al-Elwia hospital for children
complaining of excessive crying of more than
two hours.
The study done over a one year period from
the first of January 2009 to the end of
December 2009.
All febrile infants and those with acute illness
preceding the

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Publication Date
Sun Jan 04 2015
Journal Name
Journal Of Educational And Psychological Researches
The concept of physical, psychological and social self with the kindergartens
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The concept of self is considered one of the important dimensions in the human personality, because feeling of self is an important characteristic in this phase from the psychological point of view.

The first source which forms the concept of self is the physical image, where the built and appearance of the body is considered among the vital matters which determine the person's image of himself/herself. 

The current research aims to:

1) Identify the level of physical self concept at the kindergarten children.

2) Identify the level of psychological self concept at the kindergarten children.

3) Iden

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Publication Date
Sun Jun 01 2014
Journal Name
Journal Of Water Resource And Hydraulic Engineering (jwrhe)
Large Scale Field Physical Model Simulation of Roseires Dam-Break, Sudan
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Physically based modeling approach has been widely developed in recent years for the simulation of dam failure process due to the lack of field data. This paper provides and describes a physically-based model depending on dimensional analysis and hydraulic simulation methods for estimating the maximum water level and the wave propagation time from breaching of field test dams. The field physical model has been constructed in Dabbah city to represent the collapse of the Roseires dam in Sudan. Five cases of a dam failure were studied to simulate water flood conditions by changing initial water height in the reservoir (0.8, 1.0, 1.2, 1.4 and 1.5 m respectively).The physical model working under five cases, case 5 had the greatest influence of t

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Publication Date
Tue Sep 10 2024
Journal Name
Iraoi Academic Scientific Journals
The Psychological and Physical Life Difficulties of Patients with nerve fascicle
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Publication Date
Mon Apr 23 2018
Journal Name
Elibrary.ru
PHYSICAL FITNESS OF FEMALE STUDENTS FROM IRAQ AND RUSSIA: COMPARATIVE ANALYSIS
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Objective of the study was to rate and analyze the physical fitness of female students from Iraq and Russia to find similarities, differences and regularities. Sampled for the study were 44 female non-sporting students: 20 students from Pedagogical University in Bagdad; and 24 students from Russian State University of Physical Education, Sport, Youth and Tourism in Moscow. The study was designed to obtain the joints flexibility, coordination, speed-strength and static endurance rates. The Iraqi students were tested with higher coordination abilities than their Russian peers, whilst the latter were ranked higher in the speed-strength, shoulder joints and spine flexibility tests, albeit lower than their Iraqi peers in the hip flexibility test

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Publication Date
Mon Jan 01 2007
Journal Name
Atti Della “fondazione Giorgio Ronchi”
Photo-physical characterization of Rhodamine B in liquid and solid solutions
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SUMMARY. – Absorption, flourescence, quantum yield and lifetime of rhodamine B in chloroform, methanol and dimethyl sulfoxide were measured. A comparison was done of these quantities with those for solid solutions, which are obtained by mixing constant volume proportions of dye at a concentration of 1×10–4M/l with different volume proportions from the concentrated solution of polymer in chloroform and dimethyl sulfoxide. The results showed that the addition of polymer to liquid concentrated solutions (1×10–4M/l) of rhodamine B dye from expecting, which leads to development of active medium for laser dye at high concentration, increase the spectra shift toward high energies, and the luminescence quantum yield but decreasing radiative

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Publication Date
Thu Sep 15 2022
Journal Name
Al-academy
The philosophy of physical and sensory communication in the dramatic show
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Modern critical theories revealed polemical views about the reality of the existence of communication - as a necessity for building a deliberative discourse - in the theater or not. To the theory of communication with all the conditions it imposes on thinking, interaction, and emancipation of selves in different contexts.
Therefore, the current research included four chapters, the first chapter dealt with the research problem, which was represented in (the philosophy of sensory and physical communication in theatrical performance), and the first chapter included the importance of the research, its goal and its limits, and ended with defining the terminology, and the second chapter included (theoretical framework) the first topic (ph

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Publication Date
Fri Mar 31 2017
Journal Name
Journal Of Engineering
hermo-Physical and Mechanical Properties of Unsaturated Polyester /Cobalt Ferrite Composites
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Unsaturated polyester was used as a matrix which was filled with different percentages of cobalt ferrite using hand lay-up method. Cobalt ferrite was synthesized using solid state ceramic method with reagent of CoO and Fe2O3. Mechanical properties such tensile strength, Young's modulus and shore D hardness of the composite have been studied. All these properties have increased by 10% with increasing cobalt ferrite contents. Also the thermal properties such thermal conductivity and specific heat capacity are highly increased as the ferrite content increased, while the thermal diffusivity increased by 22 %. On the other hand dielectric strength of composite has been measured which increased by 50% by increasing the cobalt ferrite content.&

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
The Effect of Physical Environment and Crowded Classes on Academic Achievement
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The research problem can be summarized through focusing on the environment that surrounds students and class congestion, how these factors affect directly or indirectly the academic achievement of students, how these factors affect understanding the scientific material that the student receives in this physical environment, how classroom’s components such as seats, space With which the student can move, the number of students in the same class,  the lighting, whether natural or artificial, and is this lighting sufficient or not enough, the nature of the wall paint old or modern, is it comfortable for sight, the blackboard if it is Good or exhausted,  In addition to air-conditioning sets in summer and winter, this is on the on

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