Preferred Language
Articles
/
ijl-15
Cross-focusing Effect of Two Intense Laser Beams on Electron Plasma Wave Excitation
...Show More Authors

This paper presents the effect of relativistic and ponderomotive nonlinearity on cross-focusing of two intense laser beams in a collisionless and unmagnetized plasma. It should be noted here that while considering the self-focusing due to relativistic electron mass variation, the electron ponderomotive density depression in the channel may also be important. Therefore/these two nonlinearties may simultaneously affect the self-focusing process. These nonlinearities depend not only on the intensity of one laser but also on the second laser. Therefore, one laser beam affects the dynamics of the second beam and hence the process of cross-focusing takes place. The electric field amplitude of the excited electron plasma wave (EPW) has been calculated. Comparison of the theory with the recent experimental observations has also been presented.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Sep 15 2020
Journal Name
Al-academy
Impact of Cranbrook on Graphic Design: راقي صباح نجم الدين
...Show More Authors

  Empirical research in the disciplines of art and design has started to escalate and gather consideration within the academic community over the past few decades. However, still, graphic design tends to be a topic extremely under-researched by scholarly persons. Profound research in the field of graphic design extends far beyond the works produced by the designer himself (Khoury, 2009, p.844). In order to develop a clear insight, one needs to delve deep into the subcategories that the diverse field of graphic design is comprised of, including illustration, typography, interaction design, branding and even the impact of notable, eminent institutes from around the world that have taken the budding artists for quite a long time (Walke

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Mar 12 2020
Journal Name
Al-khwarizmi Engineering Journal
The Influence of ProcessVariables for MillingSculptured Surfaces on Surface Roughness
...Show More Authors

Increasing the variety of products that are being designed with sculptured surfaces, efficient machining of these surfaces has become more important in many manufacturing industries. The objective of the present work is the investigation of milling parameters for the sculptured surfacesthat effecting of surface roughness during machining of Al-alloy. The machining operation implemented on C-TEK CNC milling machine. The influence of the selected variables on the chosen characteristics have been accomplished using Taguchi design approach, also ANOVA had been utilized to evaluate the contributionsof each parameter on proc

... Show More
View Publication Preview PDF
Publication Date
Wed Jul 31 2019
Journal Name
Journal Of Educational And Psychological Researches
An Instructional Design According to the constructivism Model for Chemistry Subject and Its Effect on the Life Skill by the Second Intermediate Female Students
...Show More Authors

The research aims to identify the effect of teaching-learning design based on the constructivism theory on the life skills of middle stage students. The sample consisted of (60) students from one of the middle schools in Baghdad's governorate. The experimental group and control group consisted of 30 students for each group, the research tool was the life skills scale composed of (78) items. The scale proved its validity and reliability, which was found to be (0.85). The results showed a statistically significant difference in life skills between the two groups of research in favor of the experimental group, which studied the educational design according to models of constructivism theory compared to the usual method of teaching.

View Publication Preview PDF
Publication Date
Mon Jun 05 2023
Journal Name
Journal Of Engineering
Nonlinear Analysis on Torsional Strengthening Of Rc Beams Using Cfrp Laminates
...Show More Authors

This research is devoted to investigate the behavior and performance of reinforced concrete beams strengthened with externally bonded Carbon Fiber Reinforced Polymer (CFRP) laminates under the effect of torsion. In this study a theoretical analysis has been conducted using finite element code ANSYS. Six previously tested beams are used to investigate reinforced concrete beams behavior
under torsion, two of them are solid and the rest are box-section beams. Also, two beams are without CFRP reinforcement, which are used as control beams for the strengthened one, and the other four beams are strengthened with CFRP laminates with different number of layers and spacing. Numerical investigation is conducted on these beams, and comparisons b

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Mon Jun 01 2009
Journal Name
Al-khwarizmi Engineering Journal
Effect of Adding Alcohols and Gas Velocity on Gas Hold up and Mass Transfer Coefficient in Bubble Columns with Draught Tube
...Show More Authors

     The bubble columns are widely used as a two or three phase reactor in industrial chemical process such as absorption, biochemical reactions, coal liquefaction, etc. To design such a column, two main parameters should be taken in consideration, the gas hold-up (), and the liquid phase mass transfer coefficient KLa. The study includes the effect of gas velocity and the addition of alcohols on gas hold-up and mass transfer coefficient in bubble column with draught tube when the length of the column is 1.5m and the ratio of the draught tube diameter to the column diameter equals 0.5 and the air dispersion into the base of the draught tube using a multi hole tuyere is equivalent to a diameter of 0.15 mm and

... Show More
View Publication Preview PDF
Publication Date
Thu Apr 14 2016
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
Study The Effect of α-amylase Inhibitors Isolated from Plant Sources on Some Mold.: Study The Effect of α-amylase Inhibitors Isolated from Plant Sources on Some Mold.
...Show More Authors

Activity test of the inhibitors purified from barley and broad beans crop proved the inhibition activity against 6 types of rots Pencillium ssp and Aspergellusflavus and Aspergillus niger and Fusarium solani and Fusarium semitectum and Mucor with three concentrations 0.1 and 0.2 and 0.3 mg/ml, where the inhibitor purified from the second peak of broad beans proved that it had a higher inhibition activity against the growth of test rots which were 53.75 and 62.5 and 78.5 and 76.25 and 84 and 18.8% respectively, at 0.3 mg/ ml followed by the first peak of the inhibitor purified from broad beans the inhibition activity were 43.75 and 50 and 62.96 and 75 and 80 and 12.5 then the inhibitor purified from barley in which the inhibition activity

... Show More
View Publication Preview PDF
Publication Date
Tue Dec 13 2022
Journal Name
Mathematical Modelling Of Engineering Problems
Dynamic Response and Reliability Analysis of Stochastic Multi-Story Frame Structures under Random Excitation
...Show More Authors

In earthquake engineering problems, uncertainty exists not only in the seismic excitations but also in the structure's parameters. This study investigates the influence of structural geometry, elastic modulus, mass density, and section dimension uncertainty on the stochastic earthquake response of a multi-story moment resisting frame subjected to random ground motion. The North-south component of the Ali Gharbi earthquake in 2012, Iraq, is selected as ground excitation. Using the power spectral density function (PSD), the two-dimensional finite element model of the moment resisting frame's base motion is modified to account for random ground motion. The probabilistic study of the moment resisting frame structure using stochastic fin

... Show More
View Publication
Scopus Crossref
Publication Date
Wed Jun 06 2001
Journal Name
مجلة العلوم الاقتصادية والادارية
Double cross-over and cross-over with extra period designs -comparative study-
...Show More Authors

The goal of the research is to find the optimization in the test of the appropriate cross-over design for the experiment that the researcher is carrying out (under assumption that there are carry-over effects of the treatments) to posterior periods after the application period (which is often assumed to be the first period). The comparison between the double cross-over design and the cross-over design with extra period. The similarities and differences between the two designs were studied by measuring the Relative Efficiency (RE) of the experiment.

Preview PDF
Publication Date
Mon Jun 30 2025
Journal Name
Association Of Arab Universities Journal Of Engineering Sciences
Investigation of Discrete Heating Gap Size Effect on the Heat Transfer Performance in a Two Parallel Plates Channel
...Show More Authors

Heat transfer performance of two horizontal parallel plates subjected to discrete heating from the upper plate is studied and analyzed under the condition of different gap size between the heating elements with water as the working fluid. The investigation includes the variation of Reynolds number and the heat flux along with the position of the heating elements to discover the effect of different boundary conditions on the gap size variation. Results show that gap size between the heating elements has a crucial impact on the heat transfer process inside the channel, when the gap size increased a remarkable enhancement is achieved. This result is also confirmed with the investigated range of Reynolds number and the heating value. Results al

... Show More
View Publication Preview PDF
Publication Date
Sat Aug 31 2019
Journal Name
Iraqi Journal Of Physics
The Effect of Laser And Thermal Treatment on the Hardness and Adhesion Force on the Cermet Coating By Thermal Spray Technique
...Show More Authors

Ceramic coating compose from a ceramic mixture (MgO, Al2O3) and metall (Al-Ni) were produced by Thermal Spray Technique. The mixed ratio of used materials Al:Ni (50%) and 40% of Al2O3 and 10% MgO. This mixture was spray on a stainless steel substrate of type (316 L) by using thermal spray with flame method and at spraying distances (8, 12, 16 and 20) cm, then the prepared films were treated by laser and thermal treatment. After that performing a hardness and adhesion tests were eximined. The present study shows that the best value of the thermal treatment is 1000 ℃ for 30 mint; the optimum spray distance is 12 cm and most suitable laser is 500 mJ where the microscopic and mechanical character

... Show More
View Publication Preview PDF
Crossref (1)
Crossref