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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
Sun Apr 08 2018
Journal Name
Al-khwarizmi Engineering Journal
Design of Hybrid Neural Fuzzy Controller for Human Robotic Leg System
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 In this paper, the human robotic leg which can be represented mathematically by single input-single output (SISO) nonlinear differential model with one degree of freedom, is analyzed and then a simple hybrid neural fuzzy controller is designed to improve the performance of this human robotic leg model. This controller consists from SISO fuzzy proportional derivative (FPD) controller with nine rules summing with single node neural integral derivative (NID) controller with nonlinear function. The Matlab simulation results for nonlinear robotic leg model with the suggested controller showed that the efficiency of this controller when compared with the results of the leg model that is controlled by PI+2D, PD+NID, and F

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Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Engineering
Analysis of Prosthetic Running Blade of Limb Using Different Composite Materials
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Prostheses are used as an alternative to organs lost from the body. Flex-Foot Cheetah is considered one of the lower limb prostheses used in high-intensity activities such as running. This research focused on testing two samples of Flex-Foot Cheetah manufactured of two various materials (carbon, glass) with polyester and compare between them to find the foot with the best performance in running on the level of professional athlete. In the numerical analysis, the maximum principal stress, maximum principal elastic strain, strain energy; finally, the blade total deformation were calculated for both feet. In experimental work, the load-deflection test was done for foot to calculate the bending the results were very close to

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Publication Date
Mon Dec 11 2023
Journal Name
Journal Of Kufa For Chemical Sciences
Review of Analytical Methodologies for the Determination of Metronidazole and Trimethoprim in Environmental Samples
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Antibiotics are essential for treating infectious diseases, but their overuse and adverse effects are raising concerns about global public health. The pervasiveness of antibiotic contamination in aquatic environments has drawn increased attention in recent years. The primary concern regarding the release of antibiotics into the environment is the potential for microorganisms to become resistant to antibiotics. This review article summarizes the analytical methods used to determine the presence of trimethoprim and metronidazole in various environmental samples. These antibiotics have traditionally been analyzed using tandem mass spectrometry or high-performance liquid chromatography coupled to mass spectrometry; fluorescence or ultrav

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Publication Date
Mon Sep 02 2024
Journal Name
Journal Of The American Oil Chemists' Society
Direct application of tungstosilicic acid hydrate for the treatment of high free fatty acid in acidic crude palm oil and for biodiesel production
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Abstract<p>This study explored the use of industrial acidic crude palm oil (ACPO) for biodiesel production, facing a significant obstacle due to its high free fatty acid (FFA) content, which complicates the biodiesel production process. Typically, esterification is employed to convert FFAs into fatty acid methyl ester (FAME). Herein, the effectiveness of tungstosilicic acid hydrate (TSAH) as an unsupported heteropoly acid (HPA) catalyst for FFA esterification in ACPO was investigated. The FFA content was reduced from 8.43% to 0.95% under optimum conditions (4 wt% catalyst dosage, a methanol to oil molar ratio of 10:1, 150 min and a temperature of 60°C). Noteworthy, the TSAH catalyst showed stability over 7</p> ... Show More
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Publication Date
Sun Sep 03 2017
Journal Name
Baghdad Science Journal
Calculation of Lambda Doubling for 7LiH1 molecule Using the System band emission for electronic transmissions
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The A2?u-X1?g+ emission band system of 7LiH1 molecule has been calculated for Lambda doubling. The relation between wave number ?p , ?Q , ?R conducted the energies of the state of rotation F (J), and (J + 1) with rotational quantum number J, respectively, of 7LiH1 molecule for statehood A2?u using the rotation, fixed vibrational states of both the ground and raised crossovers vibrational against ???= 0 to V ' = 0-4using rotational levels J = 0 to J = 20 have found.

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Publication Date
Fri Dec 01 2023
Journal Name
City And Environment Interactions
Towards local sustainability: A case study to evaluate outdoor urban spaces in Baghdad using physiological equivalent temperature index
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Publication Date
Mon May 01 2017
Journal Name
2017 Ieee International Conference On Electro Information Technology (eit)
A high-performance non-isolated DC-DC buck converter design based on wide bandgap power devices
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Publication Date
Tue Aug 01 2023
Journal Name
Chemical Engineering Research And Design
Improvements in hydrogen evolution through a new design of coupling inexpensive nanocomposite electrocatalysts driven by high-voltage electrolysis
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Publication Date
Sun Jul 19 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Tensile force measurement by using different lingual retainer wires, bonding materials types and thickness (A comparative in vitro study)
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Background: The bonded orthodontic retainer constructed from multistrand wire and composite is an efficient esthetic retainer, which can be maintained long-term. Clinical failures of bonded orthodontic retainers, most commonly at the wire/composite interface, have been reported. This in vitro investigation aimed to evaluate the tensile forces of selected multistrand wires and composite materials that are available for use in the construction of bonded fixed retainers. Materials and Methods: The study sample includes 120 wires with three types of retainer wires (3 braided strands\ Orthotechnology, 8 braided strands\ G&H Orthodontics, 6 coaxial strands\ Orthoclassic wires), two types of adhesive (flowable\ Orthotechnology, non flowable\ G&H O

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Publication Date
Sat Jan 01 2022
Journal Name
Aip Conference Proceedings
Appraisal of intelligent notification system for smart university campus based internet of objects for social activities
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