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Microstructural Analysis of Fly Ash-based Geopolymers with various Alkali Concentration

2019-08-14 , Hui-Teng N. , Heah Cheng Yong , Yun-Ming L. , Mohd. Mustafa Al Bakri Abdullah , Yong-Sing N.

In the present work, a comparative study on the effect of different concentration of sodium hydroxide (NaOH) on fly ash-based geopolymer was investigated. The geopolymer synthesis by mixing fly ash with alkali activator (a mixture of NaOH and sodium silicate) at solid/liquid ratio of 2.5. The NaOH were used 6M, 8M, 10M, 12M and 14M with constant sodium silicate/NaOH ratio of 2.5. The geopolymers were cured at room temperature (29°C) for 24 hours and 60°C in oven for another 24 hours. The testing and analysis of the fly ash-based geopolymers were performed after 28 days. The adequate Na+ ions and densified microstructure were observed at optimum 8M-NaOH-activated fly ash-based geopolymers.

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The ProPerTies of Ground GranulaTed BlasT furnace slaG liGhTweiGhT aGGreGaTe (Gla) aT Various Molar raTio and iTs aPPlicaTion in concreTe

2023-01-01 , Rafiza Abd Razak , Hassan M.A. , Mohd. Mustafa Al Bakri Abdullah , Zarina Yahya , Ariffin M.A.M. , Ahmad Faizal Mansor , Hao D.L.C.

The effects of supplementary cementitious materials (SCM) on the characteristics and internal structure of synthetic aggregate made from ground granulated blast furnace slag are investigated in this study (GGBS). Due to its high pozzolanic activity, GGBS was shown to be superior to other SCM materials, enhancing both the strength and durability of synthetic aggregate. Because sintering uses a lot of energy and generates a lot of pollutants, using a cold-bonded approach to make low density lightweight aggregates is particularly significant from an economic and environmental standpoint. Thus, the utilisation of ground granulated blast furnace slag (GGBS) as a substitute material in the production of green artificial lightweight aggregate (GLA) using the cold bonding method was discussed in this work. Admixtures of ADVA Cast 203 and Hydrogen Peroxide were utilised to improve the quality of GLA at various molar ratios. The freshly extracted GLA was then evaluated for specific gravity, water absorption, aggregate impact, and aggregate crushing in order to determine the optimal proportion blend. As a result, the overall findings offer great application potential in the development of concrete (GCLA). It has been determined that aggregates with a toughness of 14.6% and a hardness of 15.9% are robust. The compressive strength test found that the GCLA has a high strength lightweight concrete of 37.19 MPa and a density of 1845.74 kg/m3. The porous features developed inside the internal structure of GLA have led to GCLA’s less weight compared to conventional concrete.

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Interdigitated electrodes as impedance and capacitance biosensors: A review

2017-09-26 , Mazlan N. , Muhammad Mahyiddin Ramli , Mohd. Mustafa Al Bakri Abdullah , Dewi Suriyani Che Halin , Isa S. , Talip L. , Nuaim Siddiqi Danial , Sohiful Anuar Zainol Murad

Interdigitated electrodes (IDEs) are made of two individually addressable interdigitated comb-like electrode structures. IDEs are one of the most favored transducers, widely utilized in technological applications especially in the field of biological and chemical sensors due to their inexpensive, ease of fabrication process and high sensitivity. In order to detect and analyze a biochemical molecule or analyte, the impedance and capacitance signal need to be obtained. This paper investigates the working principle and influencer of the impedance and capacitance biosensors. The impedance biosensor depends on the resistance and capacitance while the capacitance biosensor influenced by the dielectric permittivity. However, the geometry and structures of the interdigitated electrodes affect both impedance and capacitance biosensor. The details have been discussed in this paper.

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The Effect of NaOH Concentration on Palm Oil Boiler Ash (POBA) based Geopolymer Artificial Aggregate

2024-04-19 , Hao D.L.C. , Rafiza Abd Razak , Zarina Yahya , Mohd. Mustafa Al Bakri Abdullah , Subaer

Industrial wastes or by-products can be used to create artificial aggregates. Solid waste created by the palm oil industry is a significant environmental problem that requires immediate and long-term solutions. The optimal ratio of geopolymer-based palm oil boiler ash (POBA) aggregate in terms of specific gravity, water absorption, and aggregate impact value was explored in this work. Because of its high percentages of silica oxide (SiO2) and aluminium oxide (Al2O3), POBA was chosen as the primary precursor for the geopolymer (Al2O3). The POBA aggregate with the lowest specific gravity was 1.662, while all of the geopolymer-based POBA aggregates had specific gravities below 2. The geopolymer-based POBA aggregate absorbs more water than the natural aggregate. The aggregate effect value for sodium hydroxide concentrations (6M, 8M, 10M, 12M, 14M) is less than 30%, which is considered strong.

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A study of two dimensional metal carbide MXene Ti3C2 synthesis, characterization conductivity and radiation properties

2019-01-01 , Rasid Z.A.M. , Omar M.F. , Muhammad Firdaus Mohd Nazeri , Saidi S.A. , Sandu A.V. , Mohd. Mustafa Al Bakri Abdullah

Since the discovery of exceptional properties of graphene, a lot of researchers focused on the discovery of another nobel two-dimensional (2D) materials. Recently, an elegant exfoliation approaches was proposed as a method to synthesis a new family of transitional 2D metal carbide or nitrades of MXene from a layered MAX phase. A layered MAX phase of Ti3AlC2 was synthesized through pressureless sintering (PLS) the initial powder of 3TiH2/1.1Al/2C without preliminary dehydrogenation under argon atmosphere at 1350°C. An elegant exfoliation approach was used to eliminates Al from its precursor to form a layered-structure of Ti3C2. In this study, thermal conductivity of MAX phase and MXene were studied using absolute axial heat flow method to measure the abilities sample to conduct heat and the data was collected using Picolog 1216 Data Logger. Electrical conductivity of these two materials was also compared by using two-point probe, due to its simplicity. Radiation properties of 2D MXene Ti3C2 was studied by using an established radon monitor, placed in closed, fabricated container. Morphological and structural properties of this 2D material were also studied using an established FESEM and XRD apparatus. SEM images shows two types of morphology which is a layer of Ti3C2 and the agglomerates Al2O3 with graphite. XRD pattern reveals three phases in this material which is a rhombohedral Al2O3, rhombohedral graphite and rhombohedral Ti3C2 phases, respectively. Thermal and electrical conductivity of MXene were proven higher than MAX phase. Radon concentration for this material for five consecutive days explains the radiation level of this material which is under the suggestion value from US Environmental Protection Agency (EPA). From this finding, it is can conveniently say that the MXene material can be promising material for electronic application.

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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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Properties of polyaniline/graphene oxide (PANI/GO) composites: effect of GO loading

2021-09-01 , Mutalib T.N.A.B.T.A. , Tan Soo Jin , Foo Kai Loong , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah

Polyaniline/graphene oxide (PANI/GO) composites at different wt% of GO were prepared via solution method. PANI was mixed with the GO synthesized from the improved Hummer’s method. The formation of GO was confirmed via Raman and C/O ratio. Based on the FT-IR, XRD and SEM results, it confirmed the presence of both PANI and GO characteristics at 10.9°, 25.8° and 27.8° and interactions between PANI and GO particles in PANI/GO composites at different GO loading. SEM micrographs showed a folding and wrinkled surface of GO due to the defect upon oxidation process. This means that the weak π–π interactions or the agglomeration of GO have caused PANI unable to attach on the large conjugated basal planes of GO sheets. The defective domains made GO as an insulator as it contained distortions and oxygen-containing functional groups and their local decoration. Low-conductivity domain had conquered most of the GO region which later reduced the pathway of the current flow; therefore, conductivity is affected. The wrinkled structure also resulted in the low conductivity as it weakens the interfacial interaction between PANI and GO and thus disrupted the electron movement in the composites. Due to this, the electrical conductivity reached up to 1.83 × 10−10 S/cm as the GO loading increased to 50 wt%.

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Effect of Sodium Aluminate on the Fresh and Hardened Properties of Fly Ash-Based One-Part Geopolymer

2022-01-01 , Wan-En O. , Yun-Ming L. , Heah Cheng Yong , Ho Li Ngee , Mohd. Mustafa Al Bakri Abdullah , Shee-Ween O. , Sandu A.V.

The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.

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Factors of Controlling the Formation of Titanium Dioxide (TiO2) Synthesized using Sol-gel Method - A Short Review

2022-01-24 , Abdul Razak K. , Dewi Suriyani Che Halin , Mohd. Mustafa Al Bakri Abdullah , Mohd Arif Anuar Mohd Salleh , Mahmed N. , Azani A. , Chobpattana V.

There have been experiments on TiO2 thin films synthesized utilizing sol-gel techniques. The sol-gel method is a straightforward technology that gives numerous benefits to the researcher, for instance, material's reliability, reproducibility, and controllability. Following from there, it can be utilized to make high-quality nano-structured thin films. According to previous studies, the TiO2 films' characteristics occur to be highly dependent on the production parameters and initial materials utilized. Controlling the formation of TiO2 thin films with the sol-gel method was momentarily discussed here.

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Effect of polyethylene glycol and sodium dodecyl sulphate on microstructure and self-cleaning properties of graphene oxide/TiO2 thin film

2020-09-01 , Azani A. , Dewi Suriyani Che Halin , Kamrosni Abdul Razak , Mohd. Mustafa Al Bakri Abdullah , Norsuria Mahmed , Muhammad Mahyiddin Ramli , Mohd Arif Anuar Mohd Salleh , Mohd Fairul Sharin Abdul Razak , Ayu Wazira Azhari , Chobpattana V. , Kaczmarek L.

In this study, a sol gel procedure for preparation of TiO2 thin films with graphene oxide (GO) was developed. The effect of PEG and SDS addition on the microstructure of the films as well as the photocatalytic activity of the thin film was also investigated. The morphology and surface structure of the films were studied by SEM and AFM while the photocatalytic activity of the films was analyzed by measuring the degradation of methylene blue under sunlight irradiation using UV-Vis spectrophotometer. It was found that GO/TiO2 thin film with PEG shows a smaller and porous particle while GO/TiO2 thin film with SDS formed a very smooth surface and very fine particles. Therefore, in AFM analysis reveals that surface roughness decreases with the addition of PEG and SDS. Finally, the photocatalytic activity showed that GO/TiO2 thin film with SDS have the most effective self-cleaning property which degrade 64% of methylene blue that act as model of contaminants.