Now showing 1 - 10 of 34
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Study on the effects of anodizing voltage to the AAO thin film dimensional properties synthesized by single step anodization method

2021-05-03 , Shahidah Arina Shamsuddin , Mohd Nazree Derman , Uda Hashim , Muhammad Faheem Mohd. Tahir

Anodic aluminium oxide (AAO) thin film electrodes were synthesized by using a single step anodizing method in 15 °C of 0.3 M oxalic acid at five different anodizing voltage ranging from 20 V to 60 V, respectively. The effect of anodizing voltage to the AAO dimensional properties were about to be investigated. Morphological observations were all done by FESEM where the measurements and calculation were made by using ImageJ and formulas. To ensure that the pore sizes were totally depended on the anodizing voltage, etching process were done at constant duration for all samples. The correlation between all AAO dimensional properties like pores size, interpore distance, wall thickness, pore density, percentage of porosity and nanoporous oxide thickness were presented in a linear graph.

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Tool wear and surface evaluation in drilling fly ash geopolymer using HSS, HSS-Co, and HSS-TiN cutting tools

2021-04-01 , Ghazali M.F. , Mohd. Mustafa Al Bakri Abdullah , Rahim S.Z.A. , Gondro J. , Pietrusiewicz P. , Garus S. , Stachowiak T. , Sandu A.V. , Muhammad Faheem Mohd. Tahir , Korkmaz M.E. , Osman M.S.

This paper reports on the potential use of geopolymer in the drilling process, with respect to tool wear and surface roughness. The objectives of this research are to analyze the tool life of three different economy-grade drill bit uncoated; high-speed steel (HSS), HSS coated with TiN (HSS-TiN), and HSS-cobalt (HSS-Co) in the drilling of geopolymer and to investigate the effect of spindle speed towards the tool life and surface roughness. It was found that, based on the range of parameters set in this experiment, the spindle speed is directly proportional to the tool wear and inversely proportional to surface roughness. It was also observed that HSS-Co produced the lowest value of surface roughness compared to HSS-TiN and uncoated HSS and therefore is the most favorable tool to be used for drilling the material. For HSS, HSS coated with TiN, and HSS-Co, only the drilling with the spindle speed of 100 rpm was able to drill 15 holes without surpassing the maximum tool wear of 0.10 mm. HSS-Co exhibits the greatest tool life by showing the lowest value of flank wear and produce a better surface finish to the sample by a low value of surface roughness value (Ra). This finding explains that geopolymer is possible to be drilled, and therefore, ranges of cutting tools and parameters suggested can be a guideline for researchers and manufacturers to drill geopolymer for further applications.

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Mechanical and physical properties of bottom ash/fly ash geopolymer for pavement brick application

2020-03-18 , Wan Ibrahim W.M. , Mohd. Mustafa Al Bakri Abdullah , Ahmad R. , Muhammad Faheem Mohd. Tahir , Nurul Aida Mohd Mortar , Noor Azli M.A.A.

Geopolymers are amorphous to semi-crystalline with excellent physical and and mechanical properties. It has been used to become a potential binder to Ordinary Portland Cement (OPC) in certain applications due to its lower emission of carbon dioxide gases and low energy consumption sustainability criteria. Bottom Ash (BA) is one of the main industrial by-products and it is produced at the bottom of the furnace during the coal combustion process in electricity generation. The application of BA as a sustainable construction material in the building industry plays an important role in order to decrease the volume of residual waste and conserving existing natural fine aggregates. The objectives for this study is to study the effect of fly ash to bottom ash ratio and to determine the optimum ratio of fly ash to bottom ash geopolymer for pavement brick application. The chemical composition and morphology of geopolymer reinforcement was analysed by using X-ray Fluorescence and Scanning Electron Microscope. The molarity of the Sodium Hydroxide solution is fixed at 12M. The parameter used in this study are different weight percentage of fly ash geopolymer 0 wt%, 10 wt%, 20 wt%, 30 wt% and 40 wt%. The solid to liquid ratios for this study is 2.0. The curing temperature of this study is 80°C and the curing time is 24 hours. 100% of bottom ash geopolymer is used as a control variable for this study.

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Evaluation on the mechanical properties of Ground Granulated Blast Slag (GGBS) and fly ash stabilized soil via geopolymer process

2021 , Syafiadi Rizki Abdila , Mohd. Mustafa Al Bakri Abdullah , Romisuhani Ahmad , Shayfull Zamree Abd. Rahim , Małgorzata Rychta , Izabela Wnuk , Marcin Nabiałek , Krzysztof Muskalski , Muhammad Faheem Mohd. Tahir , Muhammad Syafwandi , Marek Isradi

This study intended to address the problem of damaged (collapsed, cracked and decreased soil strength) road pavement structure built on clay soil due to clay soil properties such as low shear strength, high soil compressibility, low soil permeability, low soil strength, and high soil plasticity. Previous research reported that ground granulated blast slag (GGBS) and fly ash can be used for clay soil stabilizations, but the results of past research indicate that the road pavement construction standards remained unfulfilled, especially in terms of clay’s subgrade soil. Due to this reason, this study is carried out to further investigate soil stabilization using GGBS and fly ash-based geopolymer processes. This study investigates the effects of GGBS and ratios of fly ash (solid) to alkaline activator (liquid) of 1:1, 1.5:1, 2:1, 2.5:1, and 3:1, cured for 1 and 7 days. The molarity of sodium hydroxide (NaOH) and the ratio of sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) was fixed at 10 molar and 2.0 weight ratio. The mechanical properties of the soil stabilization based geopolymer process were tested using an unconfined compression test, while the characterization of soil stabilization was investigated using the plastic limit test, liquid limit test, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results showed that the highest strength obtained was 3.15 MPA with a GGBS to alkaline activator ratio of 1.5 and Na2SiO3 to NaOH ratio of 2.0 at 7 days curing time. These findings are useful in enhancing knowledge in the field of soil stabilization-based geopolymer, especially for applications in pavement construction. In addition, it can be used as a reference for academicians, civil engineers, and geotechnical engineers.

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Interaction of Geopolymer Filler and Alkali Molarity Concentration towards the Fire Properties of Glass-Reinforced Epoxy Composites Fabricated Using Filament Winding Technique

2022-09-01 , Mohammad Firdaus Abu Hashim , Meor Ahmad Faris Meor Ahmad Tajudin , Mydin M.A.O. , Che Mohd Ruzaidi Ghazali , Yusrina Mat Daud , Mohd. Mustafa Al Bakri Abdullah , Farah Farhana Zainal , Saloma , Muhammad Faheem Mohd. Tahir , Heah Cheng Yong , Khorami M.

This paper aims to find out the effect of different weight percentages of geopolymer filler in glass-reinforced epoxy pipe, and which can achieve the best mechanical properties and adhesion between high calcium pozzolanic-based geopolymer matrices. Different weight percentages and molarities of epoxy hardener resin and high calcium pozzolanic-based geopolymer were injected into the glass fiber. By manually winding filaments, composite samples were produced, and they were then allowed to cure at room temperature. To determine how well the geopolymer matrices adhere to the fiber reinforcement, the microstructure of the composites’ surfaces and perpendicular sections were examined. Maximum values of compressive strength and compressive modulus were 94.64 MPa and 2373.58 MPa, respectively, for the sample with a weight percentage of filler loading of 30 wt% for an alkali concentration of 12 M. This is a relatively wide range of geopolymer weight percentage of filler loading from 10 wt% to 40 wt%, at which we can obtain high compressive properties. By referring to microstructural analysis, adhesion, and interaction of the geopolymer matrix to glass fiber, it shows that the filler is well-dispersed and embedded at the fiber glass, and it was difficult to determine the differences within the range of optimal geopolymer filler content. By determining the optimum weight percent of 30 wt% of geopolymer filler and microstructural analysis, the maximum parameter has been achieved via analysis of high calcium pozzolanic-based geopolymer filler. Fire or elevated temperature represents one of the extreme ambient conditions that any structure may be exposed to during its service life. The heat resistance or thermal analysis between glass-reinforced epoxy (GRE) pipe and glass-reinforced epoxy pipe filled with high calcium pozzolanic-based geopolymer filler was studied by investigating burning tests on the samples, which shows that the addition of high calcium pozzolanic-based geopolymer filler results in a significant reduction of the melted epoxy.

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Tool wear and surface evaluation in drilling fly ash geopolymer using HSS, HSS-Co, and HSS-TiN cutting tools

2021 , Mohd Fathullah Ghazli@Ghazali , Mohd. Mustafa Al Bakri Abdullah , Shayfull Zamree Abd. Rahim , Joanna Gondro , Paweł Pietrusiewicz , Sebastian Garus , Tomasz Stachowiak , Andrei Victor Sandu , Muhammad Faheem Mohd. Tahir , Mehmet Erdi Korkmaz , Mohamed Syazwan Osman

This paper reports on the potential use of geopolymer in the drilling process, with respect to tool wear and surface roughness. The objectives of this research are to analyze the tool life of three different economy-grade drill bit uncoated; high-speed steel (HSS), HSS coated with TiN (HSS-TiN), and HSS-cobalt (HSS-Co) in the drilling of geopolymer and to investigate the effect of spindle speed towards the tool life and surface roughness. It was found that, based on the range of parameters set in this experiment, the spindle speed is directly proportional to the tool wear and inversely proportional to surface roughness. It was also observed that HSS-Co produced the lowest value of surface roughness compared to HSS-TiN and uncoated HSS and therefore is the most favorable tool to be used for drilling the material. For HSS, HSS coated with TiN, and HSS-Co, only the drilling with the spindle speed of 100 rpm was able to drill 15 holes without surpassing the maximum tool wear of 0.10 mm. HSS-Co exhibits the greatest tool life by showing the lowest value of flank wear and produce a better surface finish to the sample by a low value of surface roughness value (Ra). This finding explains that geopolymer is possible to be drilled, and therefore, ranges of cutting tools and parameters suggested can be a guideline for researchers and manufacturers to drill geopolymer for further applications

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Compressive strength and thermal conductivity of metakaolin geopolymers with anisotropic insulations

2020-03-18 , Jaya N.A. , Liew Yun Ming , Mohd. Mustafa Al Bakri Abdullah , Kamarudin Hussin , Heah Cheng Yong , Bayuaji R. , Muhammad Faheem Mohd. Tahir

This research investigated the properties of thermally insulating geopolymer prepared using waste filler (fibreboard and rubber) to act as anisotropic pore/insulation. The geopolymer matrix was synthesised using metakaolin and an alkaline solution consists of sodium hydroxide solution and sodium silicate mixture. Geopolymers with varying content (0, 3, 5 and 7 layers) of coin-shaped fibreboard and expanded polystyrene are produced to examine the anisotropic insulation effect on the material characteristics. The compressive strength and thermal conductivity were determined experimentally. From the results, it is proved that the use of anisotropic insulations can improve the thermal conductivity and minimizing the reduction of compressive strength. Geopolymer incorporated with fibreboard had better performance in terms of strength while geopolymer incorporated with rubber had better thermal conductivity.

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Impedimetric transduction from a single-step thin film nanoporous aluminum oxide as a DNA sensing electrode

2024-02-01 , Shamsuddin S.A. , Subash Chandra Bose Gopinath , Mohd Nazree Derman , Jasni I. , Ibau C. , Muhammad Faheem Mohd. Tahir

A two-step anodization process has been widely used to grow a perfectly arranged Anodic Aluminum Oxide (AAO) nanoporous with high regularity and circularity. However, this method requires more time and electricity cost since the second step anodization will be conducted more than a couple of hours up to 24 h to obtain a perfect hexagonally arranged AAO. Besides, the usage of toxic chromic acid to remove the rough surface after the first anodization is not recommended. To solve this issue, a single-step of anodization method to grow AAO at 15 °C in 0.3 M of oxalic acid at 40 V for 1 h has been proposed. In this study, the growth AAO thin film will be tested as a DNA biosensor electrode. Prior to that, instead of using toxic chemicals, couple of drops of phosphoric acid solutions were used to treat the rough, uneven surfaces by promoting hydroxyl groups while at the same time widening and revealed the underneath pores. The AAO thin film is ready for the next step of surface modification without a second anodization step. Surface chemical functionalization using 3-aminopropyl-triethoxysilane (APTES) and glutaraldehyde is performed to immobilize the aminated-ssDNA probe on the surface. The electrochemical impedance technique is employed to monitor the changes in each layer of surface modifications. The charged transfer resistance (Rct) values are linearly increased with each new additional layer on the AAO surfaces during each step of surface modification and with the increase in ssDNA complementary target concentrations (10 fM-10 μM). From the performance test, the single-step AAO thin film electrode has shown great results in functioning as a DNA biosensor through a selectivity test. It has the capability to differentiate the complementary sequences from the single mismatched target with 3-fold.

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Mechanical performance, microstructure, and porosity evolution of fly ash geopolymer after ten years of curing age

2023 , Ikmal Hakem A. Aziz , Mohd. Mustafa Al Bakri Abdullah , Rafiza Abd Razak , Zarina Yahya , Mohd Arif Anuar Mohd Salleh , Jitrin Chaiprapa , Catleya Rojviriya , Petrica Vizureanu , Andrei Victor Sandu , Muhammad Faheem Mohd. Tahir , Alida Abdullah , Liyana Jamaludin

This paper elucidates the mechanical performance, microstructure, and porosity evolution of fly ash geopolymer after 10 years of curing age. Given their wide range of applications, understanding the microstructure of geopolymers is critical for their long-term use. The outcome of fly ash geopolymer on mechanical performance and microstructural characteristics was compared between 28 days of curing (FA28D) and after 10 years of curing age (FA10Y) at similar mixing designs. The results of this work reveal that the FA10Y has a beneficial effect on strength development and denser microstructure compared to FA28D. The total porosity of FA10Y was also lower than FA28D due to the anorthite formation resulting in the compacted matrix. After 10 years of curing age, the 3D pore distribution showed a considerable decrease in the range of 5–30 µm with the formation of isolated and intergranular holes.

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Experimental investigation of chopped steel wool fiber at various ratio reinforced cementitious composite panels

2021-01-01 , Amer A.A.R. , Mohd. Mustafa Al Bakri Abdullah , Liew Yun Ming , Ikmal Hakem A. Aziz , Muhammad Faheem Mohd. Tahir , Shayfull Zamree Abd. Rahim , Amer H.A.R.

The flexural toughness of chopped steel wool fiber reinforced cementitious composite panels was investigated. Reinforced cementitious composite panels were produced by mixing of chopped steel wool fiber with a ratio range between 0.5% to 6.0% and 0.5% as a step increment of the total mixture weight, where the cement to sand ratio was 1:1.5 with water to cement ratio of 0.45. The generated reinforced cementitious panels were tested at 28 days in terms of load-carrying capacity, deflection capacities, post-yielding effects, and flexural toughness. The inclusion of chopped steel wool fiber until 4.5% resulted in gradually increasing load-carrying capacity and deflection capacities while, provides various ductility, which would simultaneously the varying of deflection capability in the post-yielding stage. Meanwhile, additional fiber beyond 4.5% resulted in decreased maximum load-carrying capacity and increase stiffness at the expense of ductility. Lastly, the inclusion of curves gradually.