Preferred Language
Articles
/
bsj-1148
Calculation of Coefficients of Cassegrain Telescope Mirrors
...Show More Authors

In the present work, a program for calculating the coefficients of the Aplanatic Cassegrain Telescope (ACT) system, free from the effects of spherical and coma aberrations, were constructed. In addition, the two-mirrors of the optical system, as aspherical surfaces, were adopted. This means, that the two-equations of the mirrors are assumed to be polynomial function of five even terms only. The numerical method, least-squares curve fitting method to calculate the two-mirror coefficients system, was adopted. For choosing the values and ratios that give the best results, Rayleigh Criterion (Rayleigh Limit), for purpose of comparison and preference, was adopted.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun Dec 07 2014
Journal Name
Baghdad Science Journal
Oscillations of First Order Neutral Differential Equations with Positive and Negative Coefficients
...Show More Authors

Oscillation criterion is investigated for all solutions of the first-order linear neutral differential equations with positive and negative coefficients. Some sufficient conditions are established so that every solution of eq.(1.1) oscillate. Generalizing of some results in [4] and [5] are given. Examples are given to illustrated our main results.

View Publication Preview PDF
Crossref
Publication Date
Fri Apr 01 2016
Journal Name
Communications In Nonlinear Science And Numerical Simulation
Simultaneous determination of time and space-dependent coefficients in a parabolic equation
...Show More Authors

View Publication
Scopus (19)
Crossref (10)
Scopus Clarivate Crossref
Publication Date
Wed Mar 30 2022
Journal Name
Iraqi Journal Of Science
Retrieval of Timewise Coefficients in the Heat Equation from Nonlocal Overdetermination Conditions
...Show More Authors

     This paper investigates the simultaneous recovery for two time-dependent coefficients for heat equation under Neumann boundary condition. This problem is considered under extra conditions of nonlocal type. The main issue with this problem is the solution unstable to small contamination of noise in the input data. The Crank-Nicolson finite difference method is utilized to solve the direct problem whilst the inverse problem is viewed as nonlinear optimization problem. The later problem is solved numerically using optimization toolbox from MATLAB. We found that the numerical results are accurate and stable.

View Publication Preview PDF
Scopus (11)
Crossref (1)
Scopus Crossref
Publication Date
Fri Apr 30 2010
Journal Name
Journal Of Applied Computer Science & Mathematics
Image Hiding Using Magnitude Modulation on the DCT Coefficients
...Show More Authors

In this paper, we introduce a DCT based steganographic method for gray scale images. The embedding approach is designed to reach efficient tradeoff among the three conflicting goals; maximizing the amount of hidden message, minimizing distortion between the cover image and stego-image,and maximizing the robustness of embedding. The main idea of the method is to create a safe embedding area in the middle and high frequency region of the DCT domain using a magnitude modulation technique. The magnitude modulation is applied using uniform quantization with magnitude Adder/Subtractor modules. The conducted test results indicated that the proposed method satisfy high capacity, high preservation of perceptual and statistical properties of the steg

... Show More
View Publication Preview PDF
Publication Date
Thu Mar 26 2009
Journal Name
Iraq Journal For Science
Calculation of time Entry and Exit of satellites from Earth Shadow
...Show More Authors

The tracking of satellites motion and their path around the earth is important things in the mechanical of satellites motion. Significant parameters for the determination of time entrance and existence of the satellite could be obtained from the shadow of the earth. In the present work the tracking and time determination for entry and exit from earth shadow have been studied. In the present work we built a software for tracking the motion of satellites in orbit around the earth and determine the change of both distance and speed as a function of time. The perturbations effect on the satellite has been neglected from the earth atmosphere drag and the earth gravity and other effects. The equation for calculating the shadow is solved using num

... Show More
Publication Date
Wed Feb 08 2023
Journal Name
Iraqi Journal Of Science
Calculation of the Time Interval of Radio Storm Emitted from Jupiter
...Show More Authors

A program in Visual Basic language was designed to calculate the time interval of radio storm by predict their type at specific Local Time (LT) from Baghdad location, such storms result from the Central Meridian Longitude (CML) of system ΙΙΙ for Jupiter and phase of Io’s satellite (ФIo). These storms are related to position of Io (Io- A,B,C,D). The input parameters for this program were the observer’s location (longitude), year, month and day. The output program results in form of tables provide the observer information about the date and the LT of beginning and end of each type of emitted storm. The year 2011 was taken to apply the results within twelve month; the results of the time interval of radio storm were between (0.08h-5

... Show More
View Publication Preview PDF
Publication Date
Tue Dec 24 2024
Journal Name
Al-fatih Journal
The impact of the use of mirrors in the level of performance of some skills epeeEmpirical researchStudents on the third stage in the Faculty of Physical Education for Girls
...Show More Authors

يهدف البحث الى أعداد بعض تمرينات الاساسية لسلاح الشيش بأستخدام المرايا في تطوير قدرة مستوى تعلم الطالبات في المبارزة ومعرفة الفروق بين المجموعتين التجريبي والضابطة بتأثير استخدام المرايا في مستوى اداء بعض مهارات سلاح الشيش لطالبات المرحلة الثالثة , وقد أستخدمت الباحثتان المنهج التجريبي على عينة من طالبات المرحلة الثالثة , وقد بلغ عددهم (45) طالبة , وقد خرجت الباحثتين بعدة أستنتاجات وهي:- - أن المنهاج التعليمي

... Show More
View Publication
Publication Date
Mon Dec 05 2022
Journal Name
Baghdad Science Journal
Investigation of the Electron Coefficients of (Ar, He, N2, O2) Gases in the Ionosphere
...Show More Authors

In this study, the electron coefficients; Mean energy , Mobility and Drift velocity  of different gases  Ar, He, N2 and O2  in the  ionosphere have been calculated using BOLSIG+ program to check the solution results of Boltzmann equation results, and effect of reduced electric field (E/N) on electronic coefficients. The electric field has been specified in the limited range 1-100 Td. The gases were in the ionosphere layer at an altitude frame 50-2000 km. Furthermore, the mean energy and drift velocity steadily increased with increases in the electric field, while mobility was reduced. It turns out that there is a significant and obvious decrease in mobility as a result of inelastic collisions and in addition lit

... Show More
View Publication Preview PDF
Scopus (1)
Scopus Crossref
Publication Date
Mon Jan 30 2023
Journal Name
Iraqi Journal Of Science
New Subclasses of Meromorphically Uniformly of Multivalent Functions with Positive and Fixed Second Coefficients
...Show More Authors

      In this paper, we consider new subclasses     of meromorphic uniformly of multivalent functions in    with fixed second coefficient, we obtain the estimation of coefficients, distortion theorems, closure theorems and some other results.

View Publication Preview PDF
Scopus Crossref
Publication Date
Sat Jan 01 2022
Journal Name
3rd International Scientific Conference Of Alkafeel University (iscku 2021)
Study the effect of mixing N2 with SF6 gas on electron transport coefficients
...Show More Authors

View Publication
Scopus Crossref