Preferred Language
Articles
/
ijp-1122
Investigation of Numerical Simulation for Adaptive Optics System
...Show More Authors

In this study, the performance of the adaptive optics (AO) system was analyzed through a numerical computer simulation implemented in MATLAB. Making a phase screen involved turning computer-generated random numbers into two-dimensional arrays of phase values on a sample point grid with matching statistics. Von Karman turbulence was created depending on the power spectral density. Several simulated point spread functions (PSFs) and modulation transfer functions (MTFs) for different values of the Fried coherent diameter (ro) were used to show how rough the atmosphere was. To evaluate the effectiveness of the optical system (telescope), the Strehl ratio (S) was computed. The compensation procedure for an AO system was implemented. Analytical analysis was used to define the wave front and aberrations of the circular aperture telescope. Zernike polynomials were used to describe the residual error and figure out how much the compensation changed the measured turbulence values. The results of the computer simulation involving atmospheric turbulence reveal that elevating the ro values (4, 8, 12, 16, 20, 24, 28, 32) cm resulted in a 3.4% rise in S. However, when the adaptive optics system operated with a constant ro (20 cm), augmenting the Zernike aberration modes led to a remarkable 44% increase in S, signifying a substantial enhancement in the compensation procedure.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Jun 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
Comparison Between Partial Least Square Regression(PLSR) and Tree Regression by Using Simulation(RT).
...Show More Authors

This research discussed, the process of comparison between the regression model of partial least squares and tree regression, where these models included two types of statistical methods represented by the first type "parameter statistics" of the partial least squares, which is adopted when the number of variables is greater than the number of observations and also when the number of observations larger than the number of variables, the second type is the "nonparametric statistic" represented by tree regression, which is the division of data in a hierarchical way. The regression models for the two models were estimated, and then the comparison between them, where the comparison between these methods was according to a Mean Square

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Dec 25 2009
Journal Name
Wireless Personal Communications
A N-Radon Based OFDM Trasceivers Design and Performance Simulation Over Different Channel Models
...Show More Authors

In this paper a new method is proposed to perform the N-Radon orthogonal frequency division multiplexing (OFDM), which are equivalent to 4-quadrature amplitude modulation (QAM), 16-QAM, 64-QAM, 256-QAM, ... etc. in spectral efficiency. This non conventional method is proposed in order to reduce the constellation energy and increase spectral efficiency. The proposed method gives a significant improvement in Bit Error Rate performance, and keeps bandwidth efficiency and spectrum shape as good as conventional Fast Fourier Transform based OFDM. The new structure was tested and compared with conventional OFDM for Additive White Gaussian Noise, flat, and multi-path selective fading channels. Simulation tests were generated for different channels

... Show More
View Publication Preview PDF
Scopus (4)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Fri Apr 01 2022
Journal Name
Journal Of Engineering
Numerical study of natural convection in an annulus between two concentric cylinders provided with metal foam fins
...Show More Authors

Natural convection in an annular space provided with metal foam fins attached to the inner cylinder is studied numerically. The metal foam fins made of copper were inserted in different axial sections with three fins in each section. The temperature of the inner cylinder is kept constant while the annular outer surface is adiabatic. The thickness effect of the inner pipe wall was considered. Naiver Stokes equation with Boussinesq approximation is used for the fluid regime while Brinkman-Forchheimer Darcy model is used for metal foam. In addition, the local thermal non-equilibrium condition in the energy equation of the porous media is presumed. The effect of Rayleigh numb

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Jan 01 2021
Journal Name
International Journal Of Thermal Sciences
Experimental and numerical investigations of heat transfer enhancement in shell and helically microtube heat exchanger using nanofluids
...Show More Authors

View Publication
Scopus (51)
Crossref (48)
Scopus Clarivate Crossref
Publication Date
Thu Sep 01 2022
Journal Name
Journal Of Engineering
Assessment of Thermal Pollution at Selected Stretch of Tigris River in Baghdad by Field Observations and Numerical Simulations
...Show More Authors

Although many technological improvements are occurring in power production worldwide, power plants in third world countries are still using old technologies that are causing thermal pollution to the water bodies. Power facilities that dump hot water into water bodies are damaging aquatic life. In the study, the impact of the Al Dora thermal power plant on a nearby stretch of Tigris River in Baghdad city was assessed by measuring the temperature of the disposed of hot water in various cross-sections of the selected stretch of Tigris River, including measuring the thermal mixing length. The measurements were conducted in winter, spring, and summer. For field measurements, it was found that the impact of recovery distances

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Apr 01 2022
Journal Name
Chemical Engineering Science
Numerical modelling of flow through nodes in foams within the “dry” limit in the presence of solid particles
...Show More Authors

View Publication
Scopus Clarivate Crossref
Publication Date
Sun May 31 2020
Journal Name
Buildings
Experimental and Numerical Study of Behaviour of Reinforced Masonry Walls with NSM CFRP Strips Subjected to Combined Loads
...Show More Authors

Near surface mounted (NSM) carbon fibers reinforced polymer (CFRP) reinforcement is one of the techniques for reinforcing masonry structures and is considered to provide significant advantages. This paper is composed of two parts. The first part presents the experimental study of brick masonry walls reinforced with NSM CFRP strips under combined shear-compression loads. Masonry walls have been tested under vertical compression, with different bed joint orientations 90° and 45° relative to the loading direction. Different reinforcement orientations were used including vertical, horizontal, and a combination of both sides of the wall. The second part of this paper comprises a numerical analysis of unreinforced brick masonry (URM) wa

... Show More
Scopus (17)
Crossref (13)
Scopus Clarivate Crossref
Publication Date
Mon Jul 01 2019
Journal Name
Journal Of Engineering
Development of Bridges Maintenance Management System based on Geographic Information System Techniques (Case study: AlMuthanna \ Iraq)
...Show More Authors

A Geographic Information System (GIS) is a computerized database management system for accumulating, storage, retrieval, analysis, and display spatial data. In general, GIS contains two broad categories of information, geo-referenced spatial data and attribute data. Geo-referenced spatial data define objects that have an orientation and relationship in two or three-dimensional space, while attribute data is qualitative data that can be counted for recording and analysis. The main aim of this research is to reveal the role of GIS technology in the enhancement of bridge maintenance management system components such as the output results, and make it more interpretable through dynamic colour coding and more sophisticated vi

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Thu Nov 01 2012
Journal Name
2012 First National Conference For Engineering Sciences (fnces 2012)
Laboratory investigation in the Hydrated lime effect on asphalt concrete mixture
...Show More Authors

This investigation was undertaken to evaluate the effectiveness of using Hydrated lime as a (partial substitute) by weight of filler (lime stone powder) with five consecutive percentage namely (1.0, 1.5, 2.0, 2.5, 3.0) % by means of aggregate treatment, by introducing dry lime on dry and 2–3% Saturated surface aggregate on both wearing and binder coarse. Marshall design method, indirect tensile test and permanent deformation under repeated loading of Pneumatic repeated load system at full range of temperature (20, 40, 60) C0 were examined The study revealed that the use of 2.0% and 1.5 % of dry and wet replacement extend the pavement characteristics by improving the Marshall properties and increasing the TSR%. Finally, increase permanent

... Show More
View Publication
Crossref (2)
Crossref
Publication Date
Thu Mar 20 2025
Journal Name
3rd International Conference On Construction Engineering At: Damascus, Syria
Investigation on the Moment-Curvature Relationship in GFRP Reinforced Concrete Beams
...Show More Authors