Preferred Language
Articles
/
eRY3n4oBVTCNdQwCWqHi
MODELING AND COMPARISON OF CLOSED-LOOP AND OPENLOOP ADAPTIVE OPTICS SYSTEMS
...Show More Authors

Astronomers have known since the invention of the telescope that atmospheric turbulence affects celestial images. So, in order to compensate for the atmospheric aberrations of the observed wavefront, an Adaptive Optics (AO) system has been introduced. The AO can be arranged into two systems: closedloop and open-loop systems. The aim of this paper is to model and compare the performance of both AO loop systems by using one of the most recent Adaptive Optics simulation tools, the Objected-Oriented Matlab Adaptive Optics (OOMAO). Then assess the performance of closed and open loop systems by their capabilities to compensate for wavefront aberrations and improve image quality, also their effect by the observed optical bands (near-infrared band and visible band), the shape of the telescope aperture (circular and hexagonal) and the atmospheric seeing conditions. The results showed that open-loop systems perform better than closed-loop systems at good seeing and vice versa. Also showed that closed-loop provides stability in the correction process over time, while the open-loop is a faster phase compensator

View Publication
Publication Date
Thu Sep 30 2021
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of Some Methods for Estimating Mixture of Linear Regression Models with Application
...Show More Authors

 A mixture model is used to model data that come from more than one component. In recent years, it became an effective tool in drawing inferences about the complex data that we might come across in real life. Moreover, it can represent a tremendous confirmatory tool in classification observations based on similarities amongst them. In this paper, several mixture regression-based methods were conducted under the assumption that the data come from a finite number of components. A comparison of these methods has been made according to their results in estimating component parameters. Also, observation membership has been inferred and assessed for these methods. The results showed that the flexible mixture model outperformed the others

... Show More
Crossref
Publication Date
Thu Mar 06 2025
Journal Name
International Journal Of Applied Mechanics And Engineering
Comparison of The Mechanical Properties of Low-Cost Bio Fiber Reinforced Polymer Composites
...Show More Authors

In this study, the physical, and mechanical properties of low-cost and biocomposites were evaluated. The walnut shell and date palm frond fibers were thermally treated in an oven at a temperature of 70°C and then chemically treated with NaOH and distilled water solution, after these treatments, the biocomposite materials will be thermally treated again at 50°C. This procedure was performed for three types of biocomposite; Walnut shell Fiber Reinforced Polymer (WFRP), Date palm Fiber Reinforced Polymer (DFRP), and Hybrid Fiber Reinforced Polymer (HFRP), whereas the biocomposite sheets consisting of 30% biofibers and 70% unsaturated polyester, the mechanical test specimens were cut by a CNC machine according to ASTM standards. The e

... Show More
View Publication Preview PDF
Scopus (1)
Crossref (1)
Scopus Crossref
Publication Date
Sun Sep 07 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Comparison of fit among different types of post restorations luted with conventional cement
...Show More Authors

Background: with the advent of new postmaterial in dentistry, it has become important to measure fitness of post restoration along the horizontal plane of the root space.This study aimed to measure and compare, the cement film thickness of conventional zinc phosphate cement in micrometer between the post and root dentin along horizontal plane at different post space regions (coronal, middle and apical) of four types of posts, by using stereomicroscopy. Material and methods: Thirty-two extracted human maxillary canines, mandibular canines and maxillary central incisors (n=32) were instrumented with ProTaper system files (hand use) and obturated with gutta-percha for ProTaper and AH26® root canal sealer. After 24hrs of incubation at 37ºC, p

... Show More
View Publication Preview PDF
Publication Date
Tue Jan 01 2019
Journal Name
Desalination And Water Treatment
Numerical modeling of performance of olive seeds as permeable reactive barrier for containment of copper from contaminated groundwater
...Show More Authors

Scopus (19)
Crossref (16)
Scopus Clarivate Crossref
Publication Date
Fri May 01 2020
Journal Name
Journal Of Engineering
Effect of Maximum Size of Aggregate on the Behavior of Reinforced Concrete Beams Analyzed using Meso Scale Modeling
...Show More Authors

In this study, simply supported reinforced concrete (RC) beams were analyzed using the Extended Finite Element Method (XFEM). This is a powerful method that is used for the treatment of discontinuities resulting from the fracture process and crack propagation in concrete. The mesoscale is used in modeling concrete as a two-phasic material of coarse aggregate and cement mortar. Air voids in the cement paste will also be modeled. The coarse aggregate used in the casting of these beams is a rounded aggregate consisting of different maximum sizes. The maximum size is 25 mm in the first model, and in the second model, the maximum size is 20 mm. The compressive strength used in these beams is equal to 26 MPa.

The subje

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Sat Jan 01 2011
Journal Name
Journal: Ibn Al-haitham Journal For Pure And Applied Sciences
A Study the effect the direction of the distribution of lighting to improve Images in different lighting by using technique adaptive histogram equalization
...Show More Authors

Publication Date
Sat Jun 10 2017
Journal Name
International Journal Of Current Microbiology And Applied Sciences
A Comparison between Tilapia zilli (Gervais, 1748) (Preciformes: Cichlidae) and Common Carp Cyprinus carpio (Linnaeus, 1758) (Cypriniformes: Cyprinidae) by Staining Bone Technique
...Show More Authors

View Publication
Crossref
Publication Date
Thu Sep 01 2005
Journal Name
Journal Of Sport Sciences
Comparison study in some kinematics variables in (100) meter butterfly swimming to first and second ranking in world swimming championship Espana 2003
...Show More Authors

The aim of study was making comparison in some kinematics variables in (100) meter butterfly swimming to first and second ranking in championship 2003 Espana, so noticed there is no such like this study in our country in comparison study for international champions therefore not specific and scientific discovering to these advanced levels, also the researchers depend on group of kinematics variables when the comparison making and it was included (50 meter the first, 50 meter the second, the differences between the first (50) meter and the second , more over basic variables in (100) meter butterfly , after having the results and treat it statistically the researchers reaches to two conclusions which was: • Success the first rank in startin

... Show More
Preview PDF
Publication Date
Mon Apr 17 2017
Journal Name
Wireless Personal Communications
ITPMAP: An Improved Three-Pass Mutual Authentication Protocol for Secure RFID Systems
...Show More Authors

View Publication
Scopus (9)
Crossref (5)
Scopus Clarivate Crossref
Publication Date
Sun Sep 03 2023
Journal Name
Al-mansour Journal
Biometrics Systems Challenges in a Post-COVID-19 Pandemic World: A review
...Show More Authors

One of the most serious health disasters in recent memory is the COVID-19 epidemic. Several restriction rules have been forced to reduce the virus spreading. Masks that are properly fitted can help prevent the virus from spreading from the person wearing the mask to others. Masks alone will not protect against COVID-19; they must be used in conjunction with physical separation and avoidance of direct contact. The fast spread of this disease, as well as the growing usage of prevention methods, underscore the critical need for a shift in biometrics-based authentication schemes. Biometrics systems are affected differently depending on whether are used as one of the preventive techniques based on COVID-19 pandemic rules. This study provides an

... Show More
View Publication Preview PDF