إحدى أهم الطرق لتقصي توزيع المجرات عبر الزمن الكوني هي دالة اللمعان LF بدلالة كتلة القرص الباريوني ψS(Mb)، القدر . لقد درسنا تقديرًا لكثافة كتلة الباريون في عينة من المجرات الحلزونية القضيبية وغير القضيبية من الادبيات السابقة، والتي تتضمن فعليًا، لكل صنف من الاجرام السماوية ذات المحتوى الباريون المرئي، جزءًا لا يتجزأ من ناتج دالة الضيائية (LF) ونسبة الكتلة إلى الضوء. استخدمت تقنية الانحدار المتعدد لحزمة البرامج الإحصائية في دراستنا ونتائجنا، مثل برنامج تحليل قواعد البيانات والرسوم البيانية)برامج Statistics Win و(Origin Pro . وفقًا للتحليل الإحصائي، هناك علاقة إيجابية قوية وارتباط وثيق للغاية (α MB~1), ، وغالبًا ما تظهر المجرات الحلزونية القرصية القضيبية وغير القضيبية قدراً مطلقاً بحدود MB < -18 mag . "الركبة" لدالة الضيائية للمجرات الحلزونية تبين قطعًا كبيرًا عند كتلة باريونية تبلغ Mb > 1010 Mʘ للمجرات الحلزونية القضيبية وغير القضيبية. يوفر هذا دليلاً يدعم الفرضية القائلة بأن اللوالب الحلزونية لنظام القرص بدأت تتشكل داخل عتبة كتلة متزايدة. نظرًا لأن زيادة دالة الكتلة الأولية للنجم مع الانزياح نحو الأحمر تكون أسرع بكثير، فقد أشارت النتائج التي توصلنا إليها إلى أن دالة الكتلة الأولية المنتقلة ψS(Mb) للمجرات القضيبية وغير القضيبيةعند انزياح أحمر مرتفع z > 0.027 للمجرات االقضيبية وz > 0.02للمجرات غير القضيبية والذي يبدو أنه يتناقص مقارنة بالكون الحرج.
In this research, Artificial Neural Networks (ANNs) technique was applied in an attempt to predict the water levels and some of the water quality parameters at Tigris River in Wasit Government for five different sites. These predictions are useful in the planning, management, evaluation of the water resources in the area. Spatial data along a river system or area at different locations in a catchment area usually have missing measurements, hence an accurate prediction. model to fill these missing values is essential.
The selected sites for water quality data prediction were Sewera, Numania , Kut u/s, Kut d/s, Garaf observation sites. In these five sites models were built for prediction of the water level and water quality parameters.
This research aims to removes dyes from waste water by adsorption using banana peels. The conduct experiment done by banana powder and banana gel to compare between them and find out which one is the most efficient in adsorption. Studying the effects different factors on adsorption material and calculate the best removal efficiency to get rid of the methylene blue dye (MB).
There is an evidence that channel estimation in communication systems plays a crucial issue in recovering the transmitted data. In recent years, there has been an increasing interest to solve problems due to channel estimation and equalization especially when the channel impulse response is fast time varying Rician fading distribution that means channel impulse response change rapidly. Therefore, there must be an optimal channel estimation and equalization to recover transmitted data. However. this paper attempt to compare epsilon normalized least mean square (ε-NLMS) and recursive least squares (RLS) algorithms by computing their performance ability to track multiple fast time varying Rician fading channel with different values of Doppler
... Show More: In this study, a linear synchronous machine is compared with a linear transverse flux machine. Both machines have been designed and built with the intention of being used as the power take off in a free piston engine. As both topologies are cylindrical, it is not possible to construct either using just flat laminations and so alternative methods are described and demonstrated. Despite the difference in topology and specification, the machines are compared on a common base in terms of rated force and suitability for use as a generator. Experience gained during the manufacture of two prototypes is described.
This manuscript presents several applications for solving special kinds of ordinary and partial differential equations using iteration methods such as Adomian decomposition method (ADM), Variation iterative method (VIM) and Taylor series method. These methods can be applied as well as to solve nonperturbed problems and 3rd order parabolic PDEs with variable coefficient. Moreover, we compare the results using ADM, VIM and Taylor series method. These methods are a commination of the two initial conditions.
Seepage through earth dams is one of the most popular causes for earth dam collapse due to internal granule movement and seepage transfer. In earthen dams, the core plays a vital function in decreasing seepage through the dam body and lowering the phreatic line. In this research, an alternative soil to the clay soil used in the dam core has been proposed by conducting multiple experiments to test the permeability of silty and sandy soil with different additives materials. Then the selected sandy soil model was used to represent the dam experimentally, employing a permeability device to measure the amount of water that seeps through the dam's body and to represent the seepage line. A numerical model was adopted using Geo-Studio software i
... Show MoreBackground: Tooth decay is still one of most common diseases of childhood, child’s primary teeth are important even though they aretemporary. This study was conducted to assess the physiochemical characteristic of saliva among caries experience preschool children and compared them with caries free matching in age and gender. Then an evaluation was done about these salivary characteristics to dental caries and evaluated the relation of body mass index to dental caries and to salivary variables. Materials and method: After examination 360 children aged 4-5 years of both gender. Caries-experiences was recorded according to dmfs index by (World Health Organization criteria 1987) during pilot study children with caries experience was di
... Show MoreThe logistic regression model is an important statistical model showing the relationship between the binary variable and the explanatory variables. The large number of explanations that are usually used to illustrate the response led to the emergence of the problem of linear multiplicity between the explanatory variables that make estimating the parameters of the model not accurate.
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