1,721,729 research outputs found
Metal matrix composites reinforced with SiC long fibers and carbon nanomaterials produced by electrodeposition
Full text linkThe research work of this PhD thesis was done on the study, production and characterization of two types of metal matrix composites: 1) fiber reinforced metal matrix composites and, 2) carbon nanomaterials reinforced metal matrix composites. In fiber reinforced metal matrix composites, a metal or an alloy is reinforced with continuous or discontinuous fibers in order to improve the specific strength and stiffness at high temperatures. For example superalloys are the typical materials for the hot parts of aeronautic engines. They are very important in the aerospace field as they offer high temperature mechanical strength together with a good resistance to oxidation and corrosion. But due to high temperatures involved in the service conditions, buckling of the material may occur. In order to avoid this high temperature buckling phenomena, a reinforcement of the superalloy could be needed to maintain the mechanical properties. For this reason it was thought to investigate the possibility of realizing continuous fibers reinforced metal matrix composites over the superalloys that can further improve the high temperature properties. Due to its simplicity and viability, electrochemical deposition was chosen as the production technique to produce this kind of composite materials. The selected substrate for electrodepositing the nickel matrix composite was nickel based superalloy Inconel-718, and monofilament continuous silicon carbide fibers were chosen as reinforcement. First of all chemical compatibility was studied between the nickel matrix, superalloy and silicon carbide fibers, both in the uncoated form, and coated with carbon or carbon/titanium diboride. Both theoretical calculations and experiments were conducted, suggesting the use of a carbon coating over fibers and a buffer layer of nickel to increase the interface quality as well as to avoid unwanted reactions between substrate and silicon carbide fibers. After studying the chemical feasibility of all the related components, electrodeposition of the composites was performed in order to demonstrate the practical feasibility of the process. Then final composites were deposited on the dog-bone shaped specimens of Inconel-718. The produced composites were subjected to mechanical tests in order to evaluate the mechanical properties at room temperature and at high temperatures (400 °C and 600 °C). Evaluation of the results shows improvement in the yield strength of the produced composites with respect to the superalloy alone at room temperature. There is a decrease in the yield strength at high temperatures due to the failure of the interface between the superalloy and the composite layer but it is demonstrated that if a hot pressing treatment is done, then the interface strength is retained at high temperature and thus yield strength values will also increase. Fracture analysis and EDS analysis were also performed on the fractured surfaces of the samples with the help of field emission scanning electron microscope in order to study the fracture mechanisms involved and the composition of the interface after their testing at high temperatures. The fracture mechanisms in Ni/SiC composite layer was of debonding and pull out type which is typical characteristic of the fiber reinforced composites. The superalloy fractures with ductile behavior at room temperature. At temperatures of 400 °C and 600 °C, the superalloy fails with more ductile character after extensive amount of plastic deformation before its fracture. Carbon nanomaterials are widely being used to reinforce the metallic materials in order to improve their electrical, thermal, corrosion, wear and friction resistance for particular applications. In this part of the research work, graphene nanoplatelets (GNPs) and graphene oxide (GO) were chosen as nano reinforcements to produce nickel matrix nanocomposites with the intention to evaluate their wear and friction behavior. Gr
Decomposing the links between oil price shocks and macroeconomic indicators: Evidence from SAARC region
No full textsj-docx-1-eae-10.1177_0958305X241244516 - Supplemental material for SDG achievement through international clean energy financing and access to clean fuel and technology
No full textSupplemental material, sj-docx-1-eae-10.1177_0958305X241244516 for SDG achievement through international clean energy financing and access to clean fuel and technology by Chen Xiang Jie, Oktay Özkan, Muhammad Saeed Meo and Muhammad Ramzan in Energy & Environment</p
sj-docx-3-eae-10.1177_0958305X241244516 - Supplemental material for SDG achievement through international clean energy financing and access to clean fuel and technology
No full textSupplemental material, sj-docx-3-eae-10.1177_0958305X241244516 for SDG achievement through international clean energy financing and access to clean fuel and technology by Chen Xiang Jie, Oktay Özkan, Muhammad Saeed Meo and Muhammad Ramzan in Energy & Environment</p
DHS_Download_Account_Application – Supplemental material for Role of Maternal Education and Vaccination Coverage: Evidence From Pakistan Demographic and Health Survey
No full textSupplemental material, DHS_Download_Account_Application for Role of Maternal Education and Vaccination Coverage: Evidence From Pakistan Demographic and Health Survey by Atta Muhammad Asif, Muhammad Akbar, Muhammad Ramzan Tahir and Irshad Ahmad Arshad in Asia Pacific Journal of Public Health</p
sj-docx-2-eae-10.1177_0958305X241244516 - Supplemental material for SDG achievement through international clean energy financing and access to clean fuel and technology
No full textSupplemental material, sj-docx-2-eae-10.1177_0958305X241244516 for SDG achievement through international clean energy financing and access to clean fuel and technology by Chen Xiang Jie, Oktay Özkan, Muhammad Saeed Meo and Muhammad Ramzan in Energy & Environment</p
sj-pdf-1-pie-10.1177_09544089211027989 - Supplemental material for An entropy optimization study of non-Darcian magnetohydrodynamic Williamson nanofluid with nonlinear thermal radiation over a stratified sheet
No full textSupplemental material, sj-pdf-1-pie-10.1177_09544089211027989 for An entropy optimization study of non-Darcian magnetohydrodynamic Williamson nanofluid with nonlinear thermal radiation over a stratified sheet by Muhammad Bilal, Muhammad Ramzan, Yasir Mehmood, Mohammed Kbiri Alaoui and Ronnason Chinram in Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering</p
The effect of individual incentive towards employee performances at Tenaga Nasional Berhad, Batu Gajah, Perak / Muhammad Ramzan Razian
Full text linkThe purpose of the study is to identify the effect of incentive given towards performance of employees. Another objective is to determine the relationship between the incentives with employee performance. Individual incentive consists of bonus, merit pay, incentive awards and standard hour plan. The data was distributed and collected by 44 employees by using questionnaire and random sampling. The result was held at Tenaga Nasional Berhad, Batu Gajah that involved male and female respondent. Data collection will be analyzed using Statistical Package for Social Science (SPSS, Version 21.0). The results show that there was a relationship for all variables toward job performance. However, the relationship between all variables and job performance is weak. The limitations of study are limited in small area which is Tenaga Nasional Berhad (TNB), Batu Gajah, Perak. The research just involved 44 persons in Finance, Administrative and Customer Service departments. Time to do this researcher also limited that causes the difficulty to collect relevant data
Identification and new records of tick species on livestock from district Dera Ismail Khan, Pakistan
No full textUllah, Naimat, Jamil, Muhammad, Ramzan, Muhammad, Arshad, Aisha, Zeeshan, Muhammad, Haq (2022): Identification and new records of tick species on livestock from district Dera Ismail Khan, Pakistan. Persian Journal of Acarology 11 (1): 159-162, DOI: 10.22073/pja.v11i1.7097
Setting and curing of mortars obtained by alkali activation and inorganic polymerization from sodium silicate and silica aggregate
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