Now showing 1 - 10 of 33
  • Publication
    Surface characterization study of nanoporous anodic aluminium oxide thin film synthesized by single-step anodization
    Nanoporous anodic aluminium oxide (AAO) thin film electrodes were prepared by using a single step anodization method in 0.3 M oxalic acid at 40 V for 1 h. Electrolyte temperature was controlled and maintained at 15 °C by using ice water bath. After anodized, AAO surfaces were etched by using 5% phosphoric acid (H3PO4) solution at 30 °C to remove the AAO top rough surfaces and widening the pores. Effect of different etching duration to the pore widening was investigated at 10, 20 and 30 minutes, respectively. Regularity of the pores arrangements before and after etching were analysed by fast fourier transform (FFT) profile images that were generated from FESEM images. From observation, well ordered nanoporous structures were successfully revealed after top rough surfaces were removed by etching. Pores sizes were also found to be increased with the increasing of etching duration. Further investigations were done by x-ray diffraction (XRD) analysis and fourier transform infra-red spectroscopy (FTIR) to characterize and find out the crystallinity properties and functionalities of AAO thin film electrode surfaces.
  • Publication
    Structural, morphological and thermal properties of cellulose nanofibers from napier fiber (Pennisetum purpureum)
    ( 2020-09-01)
    Radakisnin R.
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    ; ;
    Jawaid M.
    ;
    Sultan M.T.H.
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    The purpose of the study is to investigate the utilisation of Napier fiber (Pennisetum purpureum) as a source for the fabrication of cellulose nanofibers (CNF). In this study, cellulose nanofibers (CNF) from Napier fiber were isolated via ball-milling assisted by acid hydrolysis. Acid hydrolysis with different molarities (1.0, 3.8 and 5.6 M) was performed efficiently facilitate cellulose fiber size reduction. The resulting CNFs were characterised through Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), particle size analyser (PSA), field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The FTIR results demonstrated that there were no obvious changes observed between the spectra of the CNFs with different molarities of acid hydrolysis. With 5.6 M acid hydrolysis, the XRD analysis displayed the highest degree of CNF crystallinity at 70.67%. In a thermal analysis by TGA and DTG, cellulose nanofiber with 5.6 M acid hydrolysis tended to produce cellulose nanofibers with higher thermal stability. As evidenced by the structural morphologies, a fibrous network nanostructure was obtained under TEM and AFM analysis, while a compact structure was observed under FESEM analysis. In conclusion, the isolated CNFs from Napier-derived cellulose are expected to yield potential to be used as a suitable source for nanocomposite production in various applications, including pharmaceutical, food packaging and biomedical fields.
  • Publication
    Mechanical and durability analysis of fly ash based geopolymer with various compositions for rigid pavement applications
    ( 2022) ; ; ;
    Mohd Rosli Mohd Hasan
    ;
    Andrei Victor Sandu
    ;
    Petrica Vizureanu
    ;
    Che Mohd Ruzaidi Ghazali
    ;
    Aeslina Abdul Kadir
    Ordinary Portland cement (OPC) is a conventional material used to construct rigid pavement that emits large amounts of carbon dioxide (CO2) during its manufacturing process, which is bad for the environment. It is also claimed that OPC is susceptible to acid attack, which increases the maintenance cost of rigid pavement. Therefore, a fly ash based geopolymer is proposed as a material for rigid pavement application as it releases lesser amounts of CO2 during the synthesis process and has higher acid resistance compared to OPC. This current study optimizes the formulation to produce fly ash based geopolymer with the highest compressive strength. In addition, the durability of fly ash based geopolymer concrete and OPC concrete in an acidic environment is also determined and compared. The results show that the optimum value of sodium hydroxide concentration, the ratio of sodium silicate to sodium hydroxide, and the ratio of solid-to-liquid for fly ash based geopolymer are 10 M, 2.0, and 2.5, respectively, with a maximum compressive strength of 47 MPa. The results also highlight that the durability of fly ash based geopolymer is higher than that of OPC concrete, indicating that fly ash based geopolymer is a better material for rigid pavement applications, with a percentage of compressive strength loss of 7.38% to 21.94% for OPC concrete. This current study contributes to the field of knowledge by providing a reference for future development of fly ash based geopolymer for rigid pavement applications.
  • Publication
    Properties of Blended Alkaline System Geopolymer-A Review
    Geopolymers are inorganic material that comprise of silicon(Si) and aluminium(Al) bonded by oxygen atom to form a polymer network. The binder material used for geopolymer such as fly ash and blast furnace are mostly the industrial waste or by-products containing high content of silica and aluminium which acted as precursor for geopolymerization. The raw material plays an important role in the formation of geopolymer for each material may result in different properties of geopolymer. To improve the performance of these binders, numerous studies have been focused on the production of mixes based on blends of reactive precursors. The blends usually involve a Ca-rich precursor such as granulated blast furnace slag (GGBS), and an aluminosilicate source such as metakaolin or low calcium fly ash, to promote the stable coexistence of calcium silicate hydrate (C-S-H) gels formed from the activation of the GGBS and the geopolymer gel (N-A-S-H) produced from the activation of the aluminosilicate. Thus, this paper is intended to review the properties of different type of mixes of blended alkaline system.
  • Publication
    Study on the effects of anodizing voltage to the AAO thin film dimensional properties synthesized by single step anodization method
    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.
  • Publication
    Experimental investigation of chopped steel wool fiber at various ratio reinforced cementitious composite panels
    ( 2021)
    Akrm A. Rmdan Amer
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    ; ;
    Ikmal Hakem A Aziz
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    ; ;
    Hetham A.R. Amer
    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.
  • Publication
    Correlation between Thermal Insulation Properties with Compressive Strength and Density of Lightweight Geopolymer
    This paper reports the results of an experimental work conducted to investigate the correlation between thermal insulation properties with compressive strength and density of lightweight geopolymer prepared by using fly ash as source material and combination of sodium hydroxide and sodium silicate as alkaline activator. The experiments were conducted by varying the ageing time of 3, 7, 28, 60 and 90 days, respectively. The specimens cured for a period of 90 days have presented the highest compressive strength and lowest density accompanied with satisfied value of thermal conductivity. From the results obtained, it was evident that the thermal conductivity had a high correlation coefficient with compressive strength and density.
  • Publication
    Unconfined compressive strength of various types of pavement base material: a review
    (AIP Publishing, 2020) ;
    Mohd Rosli Mohd Hasan
    ;
    ;
    Yue Yuan H.
    ;
    Acep Hidayat
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    In the highway construction industry especially for pavement base material, cement treated material is a conventional method that had been applied. Other than that, there is various types of base can be used such as cement kiln dust, reclaimed asphalt pavement, fly ash, and mine tailings. The usage of this various material can improve the unconfined compressive strength (UCS) of the base it terms of the strength. It was found that the UCS is the important properties to indicate the durability of the base. This paper summarized the material and the result of various types of base materials.
  • Publication
    Microstructural characterization of plastering mortars with CRT glass addition
    (AIP Publishing, 2020)
    F. D. Dumitru
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    A. M. Panait
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    M. A. Moncea
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    A. G. Baraitaru
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    M. V. Olteanu
    ;
    I. Marcus
    ;
    P. I. Gheorghe
    ;
    Gy Deák
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    Due to the lead content, the cathode ray tubes (CRTs) glass waste are considered a great environmental risk, as the lead ions from broken CRT glass can leach into soils when in contact with waters from landfills. Currently, the recycling techniques used for CRT glass are limited due to the different compositions of the panel, funnel and neck of the kinescope tube, however, an alternative would be their recycling in binding materials. Accordingly, the paper aims to obtain secondary raw materials that can be used in the building materials sector by using a mixture of CRT glass waste (neck and panel). The plaster mortars were obtained by replacing the sand with CRT glass (its fraction being lower than 0.31mm) in different proportions-10%, 20% and 30%. The specimens were mechanically tested after 1, 2 and 7 days of hardening. The compression strengths of the obtained plaster mortars were relatively similar to the reference sample. The specimens were characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and the results revealed a porous structure, with frequent micro-cracks. The micrographs highlighted the presence of calcium hydrosilicates and hydroaluminates, ettringite, calcium hydroxide, calcite and some unreacted particles.