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A review of ultra-high temperature materials for thermal protection system
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Abstract<p>Ultra-High Temperature Materials (UHTMs) are at the base of entire aerospace industry; these high stable materials at temperatures exceeding 1600 °C are used to manage the heat shielding to protect vehicles and probes during the hypersonic flight through reentry trajectory against aerodynamic heating and reducing plasma surface interaction. Those materials are also recognized as Thermal Protection System Materials (TPSMs). The structural materials used during the high-temperature oxidizing environment are mainly limited to SiC, oxide ceramics, and composites. In addition to that, silicon-based ceramic has a maximum-use at 1700 °C approximately; as it is an active oxidation process over low temperature and water vapor environment condition. However, a great emphasis is required for developing structural materials in oxidation and rapid heating environment where the temperature is greater than 1700 °C. This review covers briefly all main types of Thermal Protection Systems (TPSs) and all the materials are used to fabricate them with the maximum operational temperatures. Also, it covers the promised UHTMs (SiC, ZrB<sub>2</sub>, HfB<sub>2</sub>, SiB<sub>6</sub> and B<sub>4</sub>C) which are currently using for several aerospace applications, especially for TPS. Besides, it discusses the oxidation of SiC, B<sub>4</sub>C, SiB<sub>6</sub>, ZrB<sub>2</sub> and HfB<sub>2</sub>. Therefore, the carbides and borides of the transition metals, Zr and Hf have a high-melting temperature and good stability in forming high-melting temperature oxides.</p>
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Publication Date
Sat Jan 01 2022
Journal Name
Computer Networks, Big Data And Iot
A Comprehensive Study of Various DC Faults and Detection Methods in Photovoltaic System
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Publication Date
Mon Jan 25 2021
Journal Name
Engineering And Technology Journal
Performance evaluation of Photovoltaic Panels by a Proposed Automated System Based on Microcontrollers
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Publication Date
Sat Feb 05 2011
Journal Name
International Journal Of Chemical Reactor Engineering
Mass Transport Properties of a Flow-Through Electrolytic Reactor Using Zinc Reduction System
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An electrolytic process for the removal of Zn(II) from aqueous solution using a parallel amalgamated copper screens cathode operated in the flow through mode is proposed. The current-potential curves recorded at a rotating amalgamated copper disc electrode were used to determine diffusion coefficient of Zn(II). The performance of electrolytic reactor was investigated by using different flow rates at initial zinc ion concentration(48 mg/L). Taking into account the residential Zn(II) concentration, the best results were obtained for cathode potential of (-1.35 V vs. SCE) at flow rate (320 L/h). Zinc ion concentration was found to decrease from 48 mg/L to 1 mg/L during 120 min. of electrolysis. The experimental data are well correlate

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Publication Date
Tue Mar 15 2022
Journal Name
Al-academy
the indication of the scene as a symbolic system in the Iraqi theatrical
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The theatrical view reflects various connotations and intellectual and aesthetic implications, as the view includes a symbolic geometric, architectural and archetypal connotation suggestive of reality and nature, as theatrical art is the woman that reflects reality, specifically the significance of the theatrical view that reveals to us the philosophical, aesthetic and cognitive dimensions of theatrical trends, so the research came with the methodological framework, which It included the research problem (what is the significance of the scene as a symbolic system in the Iraqi theatrical performance), the importance of the research and the need for it, the research objective, the limits of the research and the most important terms.
A

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Publication Date
Thu Jan 20 2022
Journal Name
Webology
The Effect of Strategic Information System in Global Marketing Channel: A Case Study
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The research dealt with the issue of strategic information systems and its impact on the global marketing channel. As the research aims to know the strategic information systems used in the cement company. Which support the senior management in supporting decisions taken in the process of global orientation and moving to foreign markets by choosing the marketing channel that will suit the company. Product and competition with it. With other companies' products. The problem of the study focused on how to move to global markets, and any marketing channel that can be followed to move the cement product globally, what are the strategic information systems used in the company and how will it contribute to supporting senior management dec

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Publication Date
Thu Sep 06 2018
Journal Name
Al-khwarizmi Engineering Journal
Performance Augmenting of a Vertical Axis Wind Turbine using Adaptable Convergent Ducting System
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Developments are carried out to enhance the performance of vertical axis wind turbines (VAWT). This paper studies the performance of the ducted wind turbine with convergent duct (DAWT). Basically, the duct technique is utilized to provide the desired wind velocity facing the turbine. Methodology was developed to estimate the decisive performance parameter and to present the effect of the convergent duct with different inlet angles. The ducted wind turbine was analyzed and simulated using MATLAB software and numerically using ANSYS-Fluent 17.2. Result of both approaches were presented and showed good closeness for the two cases of covering angles 12  and 20 respectively. Results also showed that the convergent duct with an inlet angl

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Publication Date
Tue May 01 2018
Journal Name
Journal Of Physics: Conference Series
Partial substitution of Zn Effects on the Structural and Electrical Properties of High Temperature Hg<sub>0.95</sub>Ag<sub>0.05</sub>Ba<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>8+δ</sub> Superconductors
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Publication Date
Sun Apr 08 2018
Journal Name
Al-khwarizmi Engineering Journal
Building a Management System to Control the Construction Claims in Iraq
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The paper deals with claims in construction projects in Iraq and studies their types, causes, impacts, resolution methods and then proposes a management system to control the impacts of claims. Two parts have been done to achieve the research objective (theoretical part and practical part). The findings showed that the main types of the claims are extra work claims, different site condition claims, delay claims and the main causes of the claims are variation of the orders, design errors and omission, delay in payments by owner, variation in quantities and scheduling errors. The claims have bad impacts on the cost by increasing (10% to 25%) and also on the duration of the project by increasing from (25% to 50%).The negotiation is the main

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Publication Date
Tue Aug 01 2023
Journal Name
Journal Of Engineering
Developing a Proposed System to Organize the Investment Opportunities in Iraq
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The Iraqi government seeks to overcome the financial crisis by investing and privatizing some projects to achieve sustainable growth. Most of the investment projects in Iraq suffer from many constraints that greatly impact the success of these projects. A survey of the opinions of a group of experts was conducted to identify the most important constraints facing the investment process in Iraq. Then the experts' answers were arranged in a closed questionnaire and distributed to the research sample for which the statistical analysis was conducted. Through it, the most important (17) factors that had the greatest impact on the failure of investment projects in Iraq were reached. One of the main constraints was

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Publication Date
Wed May 14 2025
Journal Name
Reproductive Biology And Endocrinology
The aryl hydrocarbon receptor: a new frontier in male reproductive system
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Background: The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor historically recognized for its role in the regulation of toxicity mediated by environmental chemicals. Recent research points to AhR's critical participation in male reproductive physiology, particularly in spermatogenesis, hormone signaling, and the maintenance of sperm quality. Both endogenous ligands (e.g., dietary and gut microbiota-derived metabolites) and exogenous pollutants (e.g., dioxins and benzo-α-pyrene) influence AhR-mediated pathways, making it a key link between environmental exposures and male fertility. Results: This review highlights AhR's influence on the male reproductive system, emphasizing the role of endogenous AhR ligands an

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