The annual performance of a hybrid system of a flat plate photovoltaic thermal system and a solar thermal collector (PVT/ST) is numerically analyzed from the energy, exergy, and environmental (CO2 reduction) viewpoints. This system can produce electricity and thermal power simultaneously, with higher thermal power and exergy compared to conventional photovoltaic thermal systems. For this purpose, a 3D transient numerical model is developed for investigating the system's performance in four main steps: (1) investigating the effects of the mass flow rate of the working fluid (20 to 50 kg/h) on the temperature behavior and thermodynamic performance of the system, (2) studying the impacts of using glass covers on the different parts of the s

The paper is concerned with the state and proof of the existence theorem of a unique solution (state vector) of couple nonlinear hyperbolic equations (CNLHEQS) via the Galerkin method (GM) with the Aubin theorem. When the continuous classical boundary control vector (CCBCV) is known, the theorem of existence a CCBOCV with equality and inequality state vector constraints (EIESVC) is stated and proved, the existence theorem of a unique solution of the adjoint couple equations (ADCEQS) associated with the state equations is studied. The Frcéhet derivative derivation of the "Hamiltonian" is obtained. Finally the necessary theorem (necessary conditions "NCs") and the sufficient theorem (sufficient conditions" SCs") for optimality of the stat

The significance of interpretation for linguists varied , and its methods varied between appreciations, deletion, understanding the meaning

The sport of polo, the game of kings and sultans, is one of the traditional sports that has defied time throughout its long history. It has preserved its historical roots and been able to adapt to contemporary requirements, societal transformations, and temporal and spatial variables. It has moved from an aristocratic sport practiced as a form of entertainment to a professional competitive sport. It attracts many players and millions of viewers, so it is a living model of how sports develop and transform from a local tradition into global sports with organized rules managed by international institutions and with many championships worldwide. Through this, the research objectives were formulated, including exploring sports' origins. Polo in

The research focuses on the withdrawal of the United States from the nuclear agreement signed between the permanent members of the United Nations Security Council and the Islamic Republic of Iran concerning its nuclear program. This withdrawal has caused disruption in the official media discourse of the concerned countries. Therefore, the main question can be posed: Are there differences in the positions of countries related to the nuclear agreement, as well as those countries affected by it, before and after the official withdrawal of the United States on May 8, 2018?
The research aims to shed light on the trends in media discourse of the countries that signed the nuclear agreement and those affected by it b

The study aimed to identify the E-leadership practice at Princess Nora Bint Abdul Rahman University and to explore the obstacles that are facing the leaders in the implementation of E-leadership, in addition to find mechanisms to improve the practice of electronic driving at the university in light of the Corona pandemic. A descriptive analytical approach was used by depending on a questionnaire to collect the needed data. The study sample consisted of (139) heads of departments, attorneys' colleges and support Deanships universities. The study results showed that E-leadership employment recorded a medium to high degree. Especially at university, that publishing decisions electronically and uses technical means in providing its services.

The Arab realized that proverbs and their stories had a great literary and linguistic significance, accordingly, they collected them from their sources and wrote them down. Thus, researchers went in studying them in different directions. The aim of the present research is thus to study the stories of proverbs in the Holy Qur’an, Prophet’s hadiths, and in the sayings of Arabs. Such a study helps to show the extent of the relevance of their stories to the proverbs, their literary values, the points of convergence between them and what they highlight, and the extent of their proximity to reality. It further helps to determine the factors that contributed to the transformation of Quranic verses, Prophet’s hadiths, and some phrases of s

الدولة الفاطمية التي قامت في بلاد المغرب الأدنى وتوسعت إلى المشرق وحتى إلى جنوب أوربا في الأندلس إي إسبانيا والبرتغال وجزر البحر المتوسط وأصبحت دولة مترامية الأطراف بفضل الجهد الذي قام به الخلفاء الفاطميين من نشر مذهب أهل البيت العلوي . مما حدا بتلك الدولة أن تصبح في أقل من قرن واحد إمبراطورية كبيرة امتدت جذورها إلى أطراف من ممتلكات الخلافة العباسية القائمة في الشرق الإسلامي ، وكان ذلك الانتشار الكبير ناتج م

The study consisted of an introduction، two chapters and a conclusion

   The first، tagged topic (: His lineage، birth، and family)، traces the lineage، birth، and family of Abd al-Ilah Hafez.

The second topic، which came under the title (The Role of Abd al-Ilah Hafez in the printing of currency)، was concerned.

 The study relied on a large number of unpublished documents، foremost of which are the documents of the Central Bank of Iraq. It contained a lot of information about its administrative activity، its positions، orders and plans in this direction.

 The House of Books and Documents is considered Al-Manhal، which is indispensable for any research to study the royal his