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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
Mon Jun 19 2023
Journal Name
Journal Of Engineering
Water Hammer Arresters; Review Studies and Practical Experiments for Alternatives
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The current research deals with practical studies that explain to the Iraqi consumer multiple instances about the phenomenon of water hammer which occur in the water pipeline operating with pressure. It concern a practical study of the characteristics of this phenomenon and economically harmful to the consumer the same time. Multiple pipe fittings are used aimed to reduce this phenomenon and its work as alternatives to the manufactured arresters that used to avoid water hammer in the sanitary installations, while the consumer did not have any knowledge as to the non-traded for many reasons, including the water pressure decreases in the networks and the use of consumer pumps to draw water directly from the network. Study found a number of

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Publication Date
Wed Apr 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
A specimen of the internal control system on the stock in light of the application JIT system In construction companies
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Suffer most of the facilities of the high cost of inventory , which affects the high cost of the product and thus affects many administrative decisions , as well as suffer the facilities of the systems developed by the provisions of inventory control , and this problem is exacerbated in the construction sector where the inventory in the form of Construction spin of the Year for another it becomes difficult to control the cost effectively , and is the research problem in question follows: What are the implications of the use of the system in time inventory accounting system for the contracting company does kills Alrkaah to the provisions of the cost of inventory and what is the optimal approach to inventory control ? Find assumed

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Publication Date
Sat Mar 23 2024
Journal Name
ســات الـتـربــويــة والـعـلمـيــة - كــليـــة التـربـيــة - الـجـامـعـة الـعـراقـيــة الــعـدد الـثــالــث والــعــشــرون - الـمـجـلـد الـثــالث - عـلـم الـنـفـس - آذار 2024 م
A review article: The Potential Role of Anemia in the Incidence of Schizophrenia
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Schizophrenia (ZP) is a common devastating cognitive disorder; however, the etiology of its incidence remains largely unclear yet. Although some evidence blames both environ ment and genetic factor as main drivers of ZP, but the clear mechanism of their effect elusive till now. Of interest, severe anemia conditions can lead to hypoxia in CNS which disturbs the normal structures and functions of some area in the brain resulting in abnormalities in the neurons communications and decrease synaptic plasticity. Additionally, modulation of cytoskeleton constituents is thought to participate to ZP development. Recently, it has been revealed that iron deficiency, which is the main cause of anemia, has a significant impact on the cytoskeleton

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Publication Date
Mon Apr 03 2023
Journal Name
Journal Of Electronics,computer Networking And Applied Mathematics
Comparison of Some Estimator Methods of Regression Mixed Model for the Multilinearity Problem and High – Dimensional Data
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In order to obtain a mixed model with high significance and accurate alertness, it is necessary to search for the method that performs the task of selecting the most important variables to be included in the model, especially when the data under study suffers from the problem of multicollinearity as well as the problem of high dimensions. The research aims to compare some methods of choosing the explanatory variables and the estimation of the parameters of the regression model, which are Bayesian Ridge Regression (unbiased) and the adaptive Lasso regression model, using simulation. MSE was used to compare the methods.

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Publication Date
Wed Jan 01 2025
Journal Name
American Journal Of Biodiversity
Importance of Conventional Pap Smear Application for Iraqi women health: scientific review
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A Pap test can identify the pre-cancerous and cancerous problem in the vagina and uterine cervix. Cervical tumour is the easiest gynecologic disease to be diagnosed, treated and prevented using regular screening tests and follow-up. This review aimed to explore the opinion of specialists about cytological changes and the precancerous lesions with Pap smear test and visual inspection of the cervices, also to determine the relationship of this malignancy with demographic characteristics of patients. Results showed that few cervical cancer and pre-cancer were with women in postmenopausal period, but more were with women in the premenopausal period. Visual inspection of the cervix can show erosion lesions by gross inspection. Upon cytology exam

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Publication Date
Thu Jan 01 2026
Journal Name
South African Journal Of Chemical Engineering
Enhancing cooling tower efficiency using ammonium persulfate (APS) as a thermal performance additive
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Publication Date
Thu Mar 30 2023
Journal Name
Optics Continuum
Ultrafast lithium disilicate veneer debonding time assisted by a CO<sub>2</sub> laser with temperature control
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We report on using a CO2 (10.6 µm) laser to debond the lithium disilicate veneers. Sixty-four sound human premolar teeth and 64 veneer specimens were used in the study. The zigzag movement via CO2 laser handpiece along with an air-cooled jet to prevent temperature elevation above the necrosis temperature limit (5.5 C°) was applied. The optimal deboning irradiation time was super-fast, at about 5 seconds at 3 Watt CO2 laser power. It is 20 times less than any previously published work for veneers debonding. The enamel beneath the debonded veneers has been assessed by atomic force microscopy (AFM) and shear stress technique as criteria for the easiness of debonding. The

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Publication Date
Fri Aug 15 2025
Journal Name
Baghdad Science Journal
Corrosion Protection of Copper in Salt Medium by Poly 4-Hyroxyaniline Deposited via Electrodeposition Technique
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The polymer was used to inhibit the corrosion of copper metal in salt media in di erent concentrations at room temperature using potentiometric polarization measurement. The polymer was prepared by mixing (0.1 M) 4-Hydroxy aniline (C6H7NO) with (0.25M) of ammonium persulfate as the initiator using the electro-deposition technique. The polymer’s results showed that copper in (3.5%) NaCl had good corrosion resistance. The ndings demonstrate that the %IE for polymer-induced copper corrosion is 89.32% at 10 ppm concentration as a result of the 4-hydroxy aniline polymer’s adsorption from salt solution on the surface of copper metal. The numbers from the polarization method and the acquired standard data agree well. The coated copper by poly

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Publication Date
Fri Aug 15 2025
Journal Name
Baghdad Science Journal
Corrosion Protection of Copper in Salt Medium by Poly 4-Hyroxyaniline Deposited via Electrodeposition Technique
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The polymer was used to inhibit the corrosion of copper metal in salt media in different concentrations at room temperature using potentiometric polarization measurement. The polymer was prepared by mixing (0.1 M) 4-Hydroxy aniline (C6H7NO) with (0.25M) of ammonium persulfate as the initiator using the electro-deposition technique. The polymer’s results showed that copper in (3.5%) NaCl had good corrosion resistance. The findings demonstrate that the %IE for polymer-induced copper corrosion is 89.32% at 10 ppm concentration as a result of the 4-hydroxy aniline polymer’s adsorption from salt solution on the surface of copper metal. The numbers from the polarization method and the acquired standard data agree well. The coated copper by po

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Publication Date
Mon Jan 01 2018
Journal Name
Ndt &amp; E International
Porosity evaluation of in-service thermal barrier coated turbine blades using a microwave nondestructive technique
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