Preferred Language
Articles
/
6xaZHooBVTCNdQwCHJAn
A review of ultra-high temperature materials for thermal protection system
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>
Scopus Clarivate Crossref
View Publication
Publication Date
Tue Feb 01 2022
Journal Name
Journal Of Engineering
Self-Repairing Technique Based on Microcapsules for Cementitious Composites- A Review

Self-repairing technology based on micro-capsules is an efficient solution for repairing cracked cementitious composites. Self-repairing based on microcapsules begins with the occurrence of cracks and develops by releasing self-repairing factors in the cracks located in concrete. Based on previous comprehensive studies, this paper provides an overview of various repairing factors and investigative methodologies. There has recently been a lack of consensus on the most efficient criteria for assessing self-repairing based on microcapsules and the smart solutions for improving capsule survival ratios during mixing. The most commonly utilized self-repairing efficiency assessment indicators are mechanical resistance and durab

... Show More
Crossref
View Publication Preview PDF
Publication Date
Tue Aug 01 2017
Journal Name
International Journal Of Science And Research (ijsr)
View Publication
Publication Date
Tue Nov 01 2011
Journal Name
Iraqi Journal Of Applied Physics
Preview PDF
Publication Date
Wed Sep 01 2010
Journal Name
Materials &amp; Design
Scopus (13)
Crossref (10)
Scopus Clarivate Crossref
View Publication
Publication Date
Thu Dec 01 2022
Journal Name
Scientific Research Journal Of Engineering And Computer Science
Cryptography Techniques - A Review

With the explosive growth of the internet and its wide usage in our lives over the last few years, data security is one of the most important for anyone using it. Data security guarantees that the sending data can be accessed and read by only authorized persons and ensure no change happens in this data. There are many methods used to achieve this goal. One of the most common methods is cryptography, which is used to convert data to unreadable data by human eyes, except if the sender uses the same algorithm and key. This paper reviews some research dealing with cryptography and shows the different methods applied in cryptography fields for various security purposes.

Publication Date
Mon Jul 18 2022
Journal Name
World Bulletin Of Public Health (wbph)
WASTEWATER TREATMENTS: A REVIEW

Many water supplies are now contaminated by anthropogenic sources such as domestic and agricultural waste, as well as manufacturing activities, the public's concern about the environmental effects of wastewater contamination has grown. Several traditional wastewater treatment methods, such as chemical coagulation, adsorption, and activated sludge, have been used to eliminate pollution; however, there are several drawbacks, most notably high operating costs, because of its low operating and repair costs, the usage of aerobic waste water treatment as a reductive medium is gaining popularity. Furthermore, it is simple to produce and has a high efficacy and potential to degrade pollu

... Show More
Publication Date
Mon May 22 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A Studied Some of the Thermal and Electrical Properties for Particulat Polymer Composites

  This researchs the preparation of particulate polymer composites from Alkyd resin and Iraqi Burn Kaolin which were added as (20%,30%,40%,50%)and comparing  with the  polymer.  It studied Thermal conductivity and Dielectric strength for both of  the Alkyd resin and  the Composite Material.        The result showed an  increase in Dielectric strength after adding the Iraqi Burn Kaolin , also the Thermal conductivity was  increased by adding the Iraqi Burn Kaolin .

View Publication Preview PDF
Publication Date
Wed Jun 01 2022
Journal Name
Bulletin Of Electrical Engineering And Informatics
Proposed model for data protection in information systems of government institutions

Information systems and data exchange between government institutions are growing rapidly around the world, and with it, the threats to information within government departments are growing. In recent years, research into the development and construction of secure information systems in government institutions seems to be very effective. Based on information system principles, this study proposes a model for providing and evaluating security for all of the departments of government institutions. The requirements of any information system begin with the organization's surroundings and objectives. Most prior techniques did not take into account the organizational component on which the information system runs, despite the relevance of

... Show More
Scopus (2)
Scopus Crossref
View Publication
Publication Date
Thu Jul 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A Review of the Some Fixed Point Theorems for Different Kinds of Maps

The focus of this article, reviewed a generalized  of contraction mapping and nonexpansive maps and recall some theorems about the existence and uniqueness of common fixed point and coincidence fixed-point for such maps under some conditions. Moreover, some schemes of different types as one-step schemes ,two-step schemes and three step schemes (Mann scheme algorithm, Ishukawa scheme algorithm, noor scheme algorithm, .scheme algorithm,  scheme algorithm Modified  scheme algorithm arahan scheme algorithm and others. The convergence of these schemes has been studied .On the other hands, We also reviewed the convergence, valence and stability theories of different types of near-plots in convex metric space.

Crossref
View Publication Preview PDF
Publication Date
Sun Feb 03 2019
Journal Name
Iraqi Journal Of Physics
Study of weathering effect on the thermal conductivity of polyvinyl chloride before and after silicon carbide addition as packaging materials

The work was carried out in two stages. The first stage concerned
with study of silicon carbide (SiC) ratio (1.5, 2.5, 3.5, and 4.5 wt%)
effect on the Thermal conductivity of polyvinyl chloride (PVC); and
the second stage concerned with the UV – weatherizing (25, 50, and
75 hr), thermal aging (40, 50, and 60 °C), and rain- weatherizing (1,
2.5, and 4 hr) effect on the samples involved. Thermal conductivity
results proved that there was slight increase in thermal conductivity
by (SiC) loading; it increased from 0.17 W/m.K for PVC to 0.19
W/m.K for 4.5% SiC/PVC; where as it was systematically decreased
by UV- weatherizing, thermal aging, and rain- weatherizing. This
property is in a good agreement with gene

... Show More
Crossref
View Publication Preview PDF