Browsing by Department "Universiti Malaysia Perlis (UniMAP)"
  • Publication
    Correlation between pore structure, compressive strength and thermal conductivity of porous metakaolin geopolymer
    ( 2020)
    Nur Ain Jaya
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Kamarudin Hussin
    This paper investigates the effect of mixing parameters (that are, alkali concentration, AA ratio, and MK/ AA ratio) on the thermal conductivity of metakaolin geopolymers. The combination effect of foaming agent (H2O2) and surfactant (Tween 80) on the physical properties, compressive strength, and pore characteristic was also elucidated. Results showed that metakaolin geopolymer with maximum compressive strength of 33 MPa, bulk density of 1680 kg/m3 , porosity of 18% and thermal conductivity of 0.40 W/mK were achieved with alkali concentration of 10 M, AA ratio of 1.0 and MK/AA ratio of 0.8. Gradation analysis demonstrated that AA ratio was the strength determining factor. Whilst, thermal conductivity was dependent on the MK/AA ratio. Adding H2O2 and surfactant produced geopolymer foam with acceptable compressive strength (0.4–6 MPa). The geopolymer foam had bulk density of 471–1212 kg/m3 , porosity of 36–86% and thermal conductivity of 0.11–0.30 W/mK. Pore structure, size, and distribution were governed by H2O2 and surfactant dosages that have a great impact on the compressive strength. Narrower pore distribution and smaller pore diameter were achieved when both foaming agent and surfactant were used instead of foaming agent alone. The pore size and distribution varied to a greater extent with varying H2O2 contents. Surfactant illustrated distinct pore stabilizing effect at low H2O2 (<0.75 wt%) which diminished at high H2O2 content. In terms of thermal conductivity, even with increasing porosity at high H2O2 and surfactant content, the thermal conductivity did not show substantial reduction due to the interconnected pores as a result of pore coalescence
  • Publication
    Effect of Naoh molar concentration on microstructure and compressive strength of dolomite/fly ash-based geopolymers
    ( 2023)
    Emy Aizat Azimi
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Ikmal Hakem A. Aziz
    ;
    Jitrin Chaiprapa
    ;
    Kamarudin Hussin
    ;
    Petrica Vizureanu
    ;
    Sorachon Yoriya
    ;
    Marcin Nabialek
    ;
    Jerzy J. Wyslocki
    Dolomite can be used as a source of aluminosilicate to produce geopolymers; however, this approach is limited by its low reactivity. This study analyzes the viability of producing geopolymers using dolomite/fly-ash with sodium silicate and NaOH solutions (at multiple concentrations) by determining the resultant geopolymers’ compressive strengths. The dolomite/fly-ash-based geopolymers at a NaOH concentration of ~22 M resulted in an optimum compressive strength of 46.38 MPa after being cured for 28 days, and the SEM and FTIR analyses confirmed the denser surface of the geopolymer matrix. The synchrotron micro-XRF analyses confirmed that the Ca concentration exceeded that of Si and Mg, leading to the formation of calcium silicate hydrate, which strengthens the resulting geopolymers.
  • Publication
    MCMC-UniMAP Makerspace @ Perpustakaan Tuanku Syed Faizuddin Putra
    ( 2019-09-11)
    Azni Yantee Abdul Raoh
    ;
    Mazmin, Mat Akhir
    ;
    Mohd Shahrul Annuar Alawi
  • Publication
    Microstructure and high temperature Oxidation of modified ductile Ni-Resist alloy with higher Manganese content
    ( 2022)
    M.M. Rashidi
    ;
    M.H. Idris
    ;
    Z. Shayfull
    ;
    A.H. Ahmad
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    P. Pietrusiewicz
    ;
    M. Nabiałek
    ;
    J. Garus
    In this study, ductile Ni-resist with a minimum of 18 wt% nickel composition was modified. Up to 12 wt% manganese was added together with 10 wt% nickel to investigate the effects of the alloying elements on its microstructure, mechanical properties and isothermal oxidation behaviour. The results show a higher manganese composition on modified ductile Ni-resist with increased carbide formation, and a slightly decreased elevated temperature tensile strength. The addition of higher Mn [wt%] slightly increased the oxidation resistance. Three different oxide layers were observed on the modified ductile Ni-resist after 25 h hot corrosion at 765◦C.
  • Publication
    The Effect of GO/TiO2 Thin Film During Photodegradation of Methylene Blue Dye
    ( 2021)
    Azliza Azani
    ;
    Dewi Suriyani Che Halin
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Kamrosni Abdul Razak
    ;
    Mohd Fairul Sharin Abdul Razak
    ;
    V Chobpattana
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Muhammad Mahyiddin Ramli
    Titanium (IV) isopropoxide (TTIP) was used to synthesize GO/TiO2 thin films using a sol-gel spin-coating method onto a glass substrate, undergoing an heat tretment at 350 °C. Several amounts of graphene oxide (GO) (0-20mg) were weighed into a sol solution of TiO2 to produce GO/TiO2 thin films. The thin film samples were characterized by X-ray diffraction (XRD) to analyze the samples’ phase and by scanning electron microscopy (SEM) to analyze the samples’ microstructure. Physical testing such as water contact angle (WCA) was analyzed using an optical microscope with J-Image software. In contrast, the optical band gap and photodegradation of methylene blue under sunlight irradiation of the thin film was analyzed using UV-VIS spectrophotometry. GO5 thin film sample showed low-intensity anatase phase formation, where the microstructure revealed a larger surface area with the addition of GO. WCA reveals that GO/TiO2 thin film exhibits super hydrophilic properties where the angle decreases from 37.83° to 4.11°. The optical result shows that GO has improved the absorption edges by expanding into visible regions. Moreover, due to the existence of GO 3.30 eV band gap energy of TiO2 decreases from to 3.18 eV obtained by GO5. The improved adsorption edge allows Ti3+, O2 and interstitial states to be formed in low valence states with energy underneath than in the TiO2 band gap. Therefore, the photodegradation of methylene blue (MB) dye increases from 48 % to 59 % in the GO/TiO2 thin film.