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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
Fri Sep 22 2006
Journal Name
Journal Of Physical Education
The Percentage Of Success And Failure Of Some Compound Offense Skills In Basketball For Joiners
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The aim of the research is to identify the percentage of success and failure of some compound offensive skills in joiner basketball. It was evident that development only occurred though the mastery of the basic single offence skills as well as the ability to perform compound skills accurately and consistently. Not paying enough attention to compound skills leads evidentially to weakness in the athlete's level that in turn leads to mistakes in performance. Six joiner games of the best four teams in Baghdad were filmed and analyzed. The results of analyzing the compound offence skills were as follows:  There was some weakness in the athletes' ability in using compound offence skills specially receiving, dribbling and following through that

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Publication Date
Mon Jul 05 2010
Journal Name
Evolutionary Algorithms
Variants of Hybrid Genetic Algorithms for Optimizing Likelihood ARMA Model Function and Many of Problems
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Optimization is essentially the art, science and mathematics of choosing the best among a given set of finite or infinite alternatives. Though currently optimization is an interdisciplinary subject cutting through the boundaries of mathematics, economics, engineering, natural sciences, and many other fields of human Endeavour it had its root in antiquity. In modern day language the problem mathematically is as follows - Among all closed curves of a given length find the one that closes maximum area. This is called the Isoperimetric problem. This problem is now mentioned in a regular fashion in any course in the Calculus of Variations. However, most problems of antiquity came from geometry and since there were no general methods to solve suc

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Publication Date
Wed May 10 2023
Journal Name
Journal Of Planner And Development
The effect of urban obsolescence on the quality of the built environment for historical quarters
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             The centers of cities and historical quarter are exposed to a severe threat to the values of the physical and legal urban environment as a result of the value deterioration and the emergence, emergence and spread of new values on the intellectual and urban context, which generates the loss of the urban environment for its spatio-temporal continuity, flexibility, adaptation and continuity, and thus urban obsolescence, Hence the problem of the research in “the lack of comprehensiveness of studies on the phenomenon of urban obsolescence and its impact on the decline in the values of the quality of the built environment in historic

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Publication Date
Sun Jul 01 2018
Journal Name
Journal Of Educational And Psychological Researches
Analysis of computer textbooks content for intermediate stage according to the theory of multiple intelligence
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The purpose of current study is to analyze the computer textbooks content for intermediate stage in Iraq according to the theory of multiple intelligence. By answering the following question “what is the percentage of availability of multiple intelligence in the content of the computer textbooks on intermediate stage (grade I, II) for the academic year (2017-2018)? The researcher followed the descriptive analytical research approach (content analysis), and adopted an explicit idea for registration. The research tool was prepared according the Gardner’s classification of multiple intelligence. It has proven validity and reliability. The study found the percentage of multiple intelligence in the content of computer textbooks for the in

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Publication Date
Wed Jul 19 2017
Journal Name
International Journal Of Advances In Chemical Engineering And Biological Sciences
Detection of Aflatoxin M1 in Pasteurized Canned Milk and Using of UV Radiation for Detoxification
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The current study was designed to investigate the presence of aflatoxin M1 in 25 samples of pasteurized canned milk which collected randomly from some Iraqi local markets using ELISA technique. Aflatoxin M1 was present in 21 samples, the concentration of aflatoxin M1 ranged from (0.25-50 ppb). UV radiation (365nm wave length) was used for detoxification of aflatoxin M1 (sample with highest concentration /50 ppb of aflatoxin M1 in two different volumes ((25 & 50 ml)) for two different time (15 & 30 min) and 30, 60, 90 cm distance between lamp and milk layer were used for this purpose). Results showed that distance between lamp and milk layer was the most effective parameter in reduction of aflatoxin M1, and whenever the distance increase the

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Publication Date
Wed May 01 2019
Journal Name
Russian Journal Of Electrochemistry
Preparation and Characterization of Graphite Substrate Manganese Dioxide Electrode for Indirect Electrochemical Removal of Phenol
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Manganese dioxide rotating cylinder electrode prepared by anodic deposition on a graphite substrate using MnSO4 solution in the presence of 0.918 M of H2SO4. The influence of different operational parameters (MnSO4 concentration, current density, time, and rotation speed) on the structure, and morphology of MnO2 deposit film was examined widely. The structure and crystal size determined by X-ray diffraction (XRD), the morphology examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The γ-MnO2 obtained as the main product of the deposition process. It found that the four parameters have a significant influence on the structure, morphology, and roughness of the prepared MnO2 deposit. The crystal size in

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Study for evidence of bacteria contamination in the southern part of the Diyala River / Iraq
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Were studied some bacteria evidence of pollution as well as the total number of live bacteria in the waters of the Diyala river and selected five stations within the 17 km final Diyala River before its mouth in the Tigris River was the first before the new bridge of the Diyala River about 4 km and the second after the mouth of the water purification plant Rustumiya suit inverselywith temperatures

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Publication Date
Mon Sep 09 2024
Journal Name
Научный Форум
the functioning of artificial intelligence for the development of communication skills among foreigners learning Russian
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Publication Date
Mon Jan 01 2018
Journal Name
Journal Of Engineering And Applied Sciences
Effect of silver doping for performance of CdS solar cell prepared by thermal vacuum evaporation
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Publication Date
Tue Apr 26 2011
Journal Name
Evolutionary Algorithms
Variants of Hybrid Genetic Algorithms for Optimizing Likelihood ARMA Model Function and Many of Problems
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