Conference Publications

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https://hdl.handle.net/20.500.14170/193

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  • Publication
    Oxide growth behaviour of Fe-Ni-Cr alloy at high temperature oxidation
    (IOP Publishing, 2020)
    Noraziana Parimin
    ;
    Esah Hamzah
    The isothermal oxidation test has been investigated on two types of Fe-Ni-Cr alloy, namely Fe-33Ni-19Cr and Fe-40Ni-24Cr alloys. Both alloys were undergoing an isothermal oxidation test at temperature of 500? for 500 hours exposure time. The weight change per surface area of the oxidized samples has been recorded to calculate the oxidation kinetics of both alloys. The oxide growth behaviour of oxidized samples has been examined using scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) spectrometer. The oxide phase formed on the sample surface has been analyzed using x-ray diffraction (XRD) technique. The results show that both alloys were followed a parabolic rate law, indicating a diffusion-controlled oxide growth mechanism. In addition, the oxidation kinetics indicating an increasing weight gain trend as the exposure time increase. Several oxide phases had formed on the oxidized surface of both alloys, consists of Cr-rich, Ti-rich, Fe-rich and spinel oxide structure. The surface morphology of both alloys demonstrated a continuous oxide scale formed on the alloy surface. Additionally, Fe-33Ni-19Cr alloy recorded a formation of Ti-rich oxide, whereas, Fe-40Ni-24Cr alloy displayed a formation of overgrown Nb-rich oxide particle which. Roles of the precipitates in oxidation mechanism give new insights into the alloy optimization.
  • Publication
    Experiment on arm rehabilitation for muscle contraction monitoring using LabVIEW-based system
    (AIP Publishing, 2020)
    Z. Muhammad Fadil
    ;
    A. Izanoordina
    ;
    Nurul Aida Mohd Mortar
    ;
    Amarul Talip
    Patient that experiencing stroke or accident will leads to arm muscle paralysis and they could either suffer from partial arm paralysis or total arm paralysis. However, one of the challenge is to make the treatment session performs better. Currently, the patient has to go to rehabilitation centres or hospitals to get the treatment as the rehabilitation device is not portable. Furthermore, they have to go back and forth for recuperation session as accommodation or other facilities are not provided at certain rehabilitation centres. Therefore, the arm rehabilitation for muscle contraction monitoring system is developed to lessen the above issue. This project is focusing on patient's arm mobility to heal and maintain the strength of affected muscle. Thus, the doctor will be able to observe the patient's upper limb arm activity in real time monitoring using the Labview application. This system could assist the doctor to diagnose and analyse the current patient's arm performance from the recorded data. The parameters such as patient's hand grip, distal phalanges, elbow motion and bicep muscle contraction will determine the level of grip, the movement and the contraction activities via input from Arduino interface. Experiments have been conducted on 25 volunteers from different categories such as gender, age and physical condition based on proposed parameters. The results show that the development of arm rehabilitation for muscle contraction monitoring system could be used to determine the patient's condition based on the activity of finger gripped, muscle arm contraction and hand movement values as well as to strengthen the patient's arm throughout the rehabilitation process.
  • Publication
    Isolation of alkali-thermotolerant cellulolytic bacteria from spent mushroom substrate
    (IOP Publishing Ltd, 2020)
    N Y Hasnol Azahari
    ;
    S Naresh
    ;
    S N A Rozani
    ;
    Kunasundari Balakrishnan
    In this study, the isolation of new alkali-thermophilic bacteria with enhanced cellulase producing ability from the spent mushroom substrate was conducted. Repeated streaking was performed on the Microcrystalline-cellulose (MCC) to obtain a pure culture. Two thermophiles bacteria isolates were used for subsequent experiment. Morphological characteristic by gram staining and endospore staining also genetic identification of 16S rDNA was performed and the growth profile had been generated using Polymath Software. Filter paper assay (determination of enzyme activity), Bradford protein concentration were used in plotting the growth associated product curve. Based on the 16S rDNA sequencing results, the bacterium strains of Anoxybacillus geothermalis, incubated at 50˚C, pH 7 and Aeribacillus pallidus, incubated at 60˚C, pH 8 was successfully isolated. Both strains are gram-positive and endospore-forming bacteria. Based on the growth curve, the doubling time for Anoxybacillus geothermalis was calculated to be 49.5 minutes. Whereas, doubling time of Aeribacillus pallidus was 56.7 minutes. Both strains represent the growth assosiated product curve in which, when product formation is growth associated the specific rate of the product formation increases with specific growth rate and vice versa.
  • Publication
    Thermal pyrolysis of empty fruit bunch (EFB) in a vertical fixed-bed reactor
    (IOP Publishing, 2020)
    Alina Rahayu Mohamed
    ;
    A N Awang
    ;
    Noor Hasyierah Mohd Salleh
    ;
    R Badlishah Ahmad
    In the production of crude palm oil, huge quantities of solid biomass waste is generated such as empty fruit bunch (EFB), palm fronds and palm–pressed fibre (PPF). This inevitably resulted in the environmental pollution due to its natural conversion to methane. In this study, thermal pyrolysis of EFB was conducted using a fixed bed reactor. The factors such as nitrogen gas flowrate and holding time that affect the distribution of pyrolysis product yields were being investigated by evaluating the percentage product yields. It was determined that at nitrogen gas flowrate of 300 cm3/min and 30 mins holding time, the maximum bio-oil yield of 46.20 % was attained with gas and char yield of 21.79 % and 32.01 % respectively. The existence of functional groups in bio-oil was analyzed by Fourier Transfrom Infra-Red (FTIR) spectroscopy. It was identified that the bio-oil has several functional groups such as hydroxyl (OH), ketone/aldehyde (C=O) and ester (O-C=O) groups. The dynamic viscoscity of bio-oil was analyzed by Brookfield viscometer. It showed that the viscosity of bio-oil decreased with increasing temperature from 25-50 °C.
  • Publication
    Durability properties of demineralized and torrefied Empty Fruit Bunch (EFB) pellets
    (IOP Publishing, 2020)
    Alina Rahayu Mohamed
    ;
    Ras Izzati Ismail
    ;
    Rashid, Mohammad Abdur
    ;
    Khairunissa Syairah Ahmad Sohaimi
    ;
    N N Kasim
    ;
    R Badlishah Ahmad
    The pelletization of raw and demineralized and torrefied empty fruit bunch (TDEFB) were conducted upon mixing with bio-oil that was obtained from EFB pyrolysis. The ratio of bio-oil addition to raw and TDEFB was varied from 0-20 wt%. Then it was pressed using the single pellet press machine. The effects of the ratio of bio-oil addition to raw and TDEFB and the thickness of pellets were evaluated towards its durability. It was identified that the ratio of bio-oil addition to raw and TDEFB pellet of 5 wt% had produced the optimum durability which was 69.27 and 74.46 % respectively. In terms of the thickness of the raw and torrefied pellets, it was determined that at thickness of 3 cm, the durability was the highest which were 70.12 and 71.12 % for both raw and TDEFB pellets respectively. The raw and TDEFB pellets were analysed using Fourier Transform Infra-Red (FTIR) spectroscopy in order to evaluate the presence of functional groups within the materials. The presence of O-H hydroxyl group, C=O from carbonyl or ester and C-H alkane groups are detected in both raw and torrefied pellets.
  • Publication
    Indoor environment quality (IEQ): temperature and indoor air quality (IAQ) factors toward occupants satisfaction
    (IOP Publishing Ltd., 2020)
    Siti Nur Aishah Mohd Noor
    ;
    Ha Haw Ding
    In Malaysia, the demand for green building kept rising from year to year. The design concept of the green building which provides better indoor environment to make occupant more comfortable and healthier. The Green Building Index (GBI) as a rating system in Malaysia was used to evaluate the environmental design and performance of a building by the occupant, due to that, it is used for this research to investigate the relationship between the indicator of the Indoor Environment Quality (IEQ) and occupant satisfaction’s element in a private university in Sarawak. The building occupants are the most important feedback to determine the occupant’s satisfaction level for IEQ within the campus. A quantitative method was applied to reach the objectives by using simple random sampling. A total of 254 copies of the questionnaire survey form were distributed to respondents at School of Business and Management (SBM) and School of Built Environment (SBE) in the university. However, there are only 238 responds are usable for this research. The result shows that the temperature (57.0%) and the indoor air quality (66.7) in IEQ’s indicator had moderate positive and significant relationship with thermal comfort, and ventilation respectively.
  • Publication
    The growth morphology and yield of Grey Oyster mushrooms (Pleurotus sajor-caju) subjected to different durations of ultrasonic sound treatment
    (IOP Publishing, 2020)
    Roshita Ibrahim
    ;
    Ooi Kar Yie
    ;
    Mazlin Nur Iman Bt. Hasnoel Mazidi
    Grey oyster mushroom (Pleurotus sajor-caju) is a type of edible mushroom that suitable to be cultivated in Malaysia. There is an increasing demand in the market due to its high nutritional values. In this study, effects of different durations of ultrasonic treatment on the growth morphology, yield enhancement and quality of mushrooms were investigated. Four different durations of ultrasonic treatment had been applied on the mushroom bags which were 1.5, 3.0, 4.5 and 6.0 minutes and 0 minutes act as control. The results showed that all ultrasonic treated bags had shorter time for mycelium to fill-up the mushroom bags as compared to control. Ultrasonic treated bags was observed could promote and activate the pinhead emergence and fruiting bodies formation. Besides, all ultrasonic treated bags also showed higher yield and better quality in terms of the largest pileus diameter of mushrooms as compared to control. For the color of mushrooms, there was no significant different (P>0.05) observed in L∗ values. However, treatment of 1.5 minutes had the highest a∗ (redness) and b∗ (yellowness) values. Different durations of ultrasonic treatment did not showed any significant different in texture and moisture content of mushrooms. In summary, 1.5 minutes was the best treatment duration as it took the shortest time for different growth stages with the greatest yield of mushrooms.
  • Publication
    High temperature isothermal oxidation of heat-treated HR-120 Ni-based alloys
    (IOP Publishing, 2020)
    Noraziana Parimin
    ;
    Esah Hamzah
    The effect of heat treatment of HR-120 Ni-based alloys on the isothermal oxidation at high temperature was studies. HR-120 Ni-based alloys was undergo a heat treatment process at two different temperatures, namely 1000 °C and 1200 °C for 3 h soaking time, followed by water quench. The heat-treated samples were then undergoing an isothermal oxidation test at 500 °C for 500 h exposure time in air. Oxidized samples have been characterized in terms of the kinetics of oxidation, phase analysis using x-ray diffraction (XRD) and oxide surface morphology using scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM) equipped with energy dispersive x-ray (EDX) spectrometer. The heat treatment process exhibits an increasing of average grain size alloy as the temperature increases. Whereas, the oxidation kinetics of oxidized samples exhibits a parabolic rate law, representing a diffusion-controlled oxide growth rate. The oxidized of heat-treated sample at 1000 °C recorded low oxidation rate with low parabolic rate constant values. The oxide surface morphology of oxidized samples indicates the formation of continuous oxide scales with overgrown Nb-rich oxide particles after exposure for 300 h. At 500 h exposure time, the formation of Nb-rich oxide particles was growing with evidence of crack occurred around the overgrown oxide particles.
  • Publication
    The changes on morphological and absorption ability of treated corn stalk fiber
    (IOP Publishing, 2020)
    M H H Mohamad Rosdi
    ;
    Nor Azwin Ahad
    Natural fiber like corn stalk fiber nowadays can be used to replace synthetic fiber. However, their natural properties may influence their performance which making hem limited to use. In this research study, variety types of chemical treatment which economical technique was used to modified the physical and chemical properties of corn stalk fiber. After the treatment process, the surface morphology and water absorption ability of the fiber was examined. There was an improvement on surface morphological by making them clean and rough compared to untreated corn stalk fiber. The hydrophobicity of corn stalk fiber also increased after treatment. As we can see, H2SO4-treated fiber has lowest water absorption ability compared to others. By removing the unnecessarily element on the fiber which comparable with synthetic fiber may increase their potential to become first choice as reinforcement materials in composite industries later.
  • Publication
    Fresh state and mechanical properties of SCC-POFA-CF mixture
    (IOP Publishing, 2020)
    M.A. Iman
    ;
    N. Mohamad
    ;
    Fasya Raain
    ;
    Anis Sofia Sufian
    ;
    Azree Mydin
    ;
    A.A.A. Samad
    This paper presents the fresh state and mechanical properties of self-compacting concrete (SCC) with addition of coir fiber (CF) as filler in range of 0.2% to 0.6% and replacing the cement in 10% with palm oil fuel ash (POFA). The workability test such as slump flow and J-ring test were used on the fresh SCC-POFA-CF mixture. The mechanical properties of SCC- POFA-CF in form of compressive, tensile and flexural strength were determine using the compressive test on cube, split tensile test on cylinder and four-point bending test on prism respectively. The increasing amount of CF in mixture resulting the decreasing of workability of SCC-POFA-CF. The SCC mixture with 0.2% CF was selected as optimum as the strength reached the allowable limit of strength. The less crack was occurred on SCC-POFA-CF compared to the control specimen. Therefore, the propagation of crack in prism of SCC was control by coir fiber.
  • Publication
    Bioprotein optimization from spent mushroom substrate for fish feed application
    (AIP Publishing, 2020)
    Nuradibah Mohd Amer
    ;
    Z. Masyitah
    ;
    Sam Sung Ting
    ;
    Khairul Farihan Kasim
    ;
    Nik Noriman Zulkepli
    ;
    Omar S. Dahham
    ;
    Saad S. Dahham
    The utilization of spent mushroom substrate as potential substrate for bioprotein production is being explored in this study. The objectives of this study were to screen three different types of fungi in bioprotein production from spent mushroom substrate and to optimize the process condition of the best fungi for production of bioprotein by using Design Expert Software. In this present study, screening of three different strains; Aspergillus terreus UniMAP AA-1, Aspergillus niger (ATCC 16404) and Phanerochaete chrysosporium (ATCC 24725), was done for bioprotein production by solid state fermentation process. P. chrysosporium produced the highest amount of protein on the sixth day, with the amount of 0.3951 mg/mL. Optimization of two parameters; substrate concentration and inoculum size for the selected fungi, P. chrysosporium was done conducted by Response Surface Methodology (RSM): Central Composite Design (CCD) to investigate optimal condition of bioprotein production. The optimum condition for P. chrysosporium to produce bioprotein using SMS was achieved at 60% of substrate concentration and 15% (w/v) of inoculum size with maximum protein concentration of 0.3812 mg/mL.
  • Publication
    UV-visible performance of urea beads coated with banana peels bioplastic and epoxidized natural rubber
    (AIP Publishing, 2020)
    S. A. Abdul Shukor
    ;
    Rosniza Hamzah
    ;
    Nik Noriman Zulkepli
    ;
    Omar S. Dahham
    ;
    N. A. Faris
    ;
    Saad S. Dahham
    ;
    Haliza Jaya
    This study describes UV-Visible (UV-Vis) performance of urea beads coated with banana peels bioplastics and epoxidized natural rubber (ENR-50). Both banana peels bioplastics and ENR-50 were used as coating materials to the urea beads. Three different type of salts which are NaCl, MgCl2 and MgSO4 with different concentrations was added to this coating materials to produce pores and later modify the release rate of urea. UV-Vis spectroscopy techniques was applied to study the performance of urea release rate. The results of 30 days release study indicate the performance of coating materials is depend on types and its salts concentration. The addition of 5 wt% of MgSO4 salt recorded lowest urea concentration at 3 mg/mL, followed by 15 wt% of NaCl at 4.4 mg/mL and 5 wt% of MgCl2 at 9 mg/mL respectively.
  • Publication
    Effect of halogen free-flame retardants on the mechanical and morphological properties of Kenaf/Polyurethane foam composites
    (IOP Publishing, 2020)
    Nur Suhaili Mohd Soberi
    ;
    Rozyanty Rahman
    ;
    Firuz Zainuddin
    ;
    Hazim Mohamad Amini
    Kenaf/polyurethane foam (PUF) was synthesized form PUF and kenaf core fiber with expandable graphite (EG) and aluminum hydroxide (ATH) at varying amounts. In the production of polymer foam composites, the processing methods determine the properties of the final products. In this work, the potential of high energy milled on EG has reduced the EG platelet size to improve its dispersion in PUF matrix. From the results obtained, PU/KF/6ATH/10EG shows the highest mechanical properties, i.e. modulus and compression strength, while PU/KF/2ATH/5EG shows the lowest mechanical properties. Scanning Electron Microscope (SEM) shows the effect of adding kenaf fiber, EG and ATH in PUF to the foam cell structure and size.
  • Publication
    Glucose production from sugarcane bagasse by two stages chemical pretreatment & hydrolysis
    (IOP Publishing, 2020)
    Nurul Syiffa Husna Che Roslan
    ;
    Midhat Nabil Ahmad Salimi
    The aim of this work was to produce glucose from sugarcane waste. It consists of high cellulose, hemicellulose and lignin which enables to be converted into a glucose production. Three conditions of acid hydrolysis was measured by using One Factor at a Time (OFAT) which consist of sulphuric acid concentration, retention time and temperature. The highest yield and optimum conditions from OFAT parameters were further continue with the enzymatic hydrolysis by using Central Composite Design (CCD). The optimization of enzymatic hydrolysis for the conversion of cellulose to glucose was conducted by using three independent variables which were pH, temperature and enzyme dosage. Based on the data of Design of Expert (DOE) software from optimization of enzymatic hydrolysis, the optimum glucose production was determined by using Dinitrosalicylic Acid Reagent (DNS) method.
  • Publication
    Study of thermoelectric properties of Sr₀.₉₂A₀.₀₈TiO₃ (A=Yb / Tm) perovskite oxide using density functional theory method
    (IOP Publishing, 2020)
    Akeem Adekunle Adewale
    ;
    Abdullah Chik
    ;
    Ruhiyuddin Mohd Zaki
    The first principle methods have been employed to investigate electronic and thermoelectric properties of Sr₀.₉₂Yb₀.₀₈TiO₃ and Sr₀.₉₂Tm₀.₀₈TiO₃ perovskite-oxide based molded samples. Generalized gradient approximation (GGA) with Hubbard U parameter is used by WIEN2k code for the calculations. The straight band line was observed in the band structure of both studied samples. This was generated from 4f-orbitals as shown in partial density of state diagrams. It is also noticed that Yb and Tm doped in SrTiO₃ changed the perovskite-based oxide from a wideband insulator to metallic nature. A thermoelectric power factor of Sr₀.₉₂Tm₀.₀₈TiO₃ sample is higher than that of Sr₀.₉₂Yb₀.₀₈TiO₃, this is as a result of its huge electrical conductivity. The dependent of chemical potential to temperature was revealed in the study where high value of power factor was recorded for high temperature.
  • Publication
    Properties and flexural behavior of self-compacting concrete with added coir fiber and POFA
    (IOP Publishing, 2020)
    Afif Iman
    ;
    N Mohamad
    ;
    Fasya Raain
    ;
    Anis Sofia Sufian
    ;
    Azree Mydin
    ;
    A A A Samad
    This paper presents the mechanical properties and flexural behavior of self-compacting concrete (SCC) with addition of 0.2%, 0.4% and 0.6% coir fiber (CF) as filler, and 10% palm oil fuel ash (POFA) as partial cement replacement. Fresh SCC-POFA-CF mixture was tested under slump flow and J-ring tests to determine its workability. SCC-POFA-CF cubes and cylinders were tested under compressive and tensile tests to determine its compressive strength, tensile strength, and flexural strength, while prisms were tested under four point bending load to determine its flexural behavior. It is found that workability of SCC-POFA-CF decreased when CF increased. The optimum percentage of CF in SCC mixture was found to be 0.4%. SCC-POFA-CF experienced less crack compared to the control specimen. This shows that CF in SCC prisms managed to control the crack propagation.
  • Publication
    Effect of sintering temperature on the preparation and characterization of green glass ceramic from rice husk ash as a matrix
    (Trans Tech Publications Ltd., 2020)
    Shahrizam Saad
    ;
    Abdullah Chik
    ;
    Khairel Rafezi Ahmad
    ;
    Sharifah Shahnaz Syed Bakar
    Powder metallurgy technique were proved successful net-shape technology which suitable for the production of green glass ceramic (GGC) from rice husk ash (RHA) and characterized by good physical and mechanical properties of glass ceramic. In this research, the glass sample was formed by mixing varying percentage of weight of silica, flux and additives. The aim of this work is to study the effect of the sintering temperature to the physical and mechanical properties of GGC. The samples were mixed in different volume fraction of additives which is 5%, 10% and 15% in constant composition of RHA and flux. The mixture was consolidated into rigid die compaction at 300MPa, then sintered at 450, 550 and 750°C. Vickers hardness test were investigated. The glass composite were then characterize by scanning electron microscopy (SEM). The GGC with 10% additives at sintering temperature 550°C shows highest hardness strength which is about 213.0 HV.
  • Publication
    Electronic properties of calcium and zirconium co-doped BaTiO₃
    (Trans Tech Publications Ltd., 2020)
    Akeem Adekunle Adewale
    ;
    Abdullah Chik
    ;
    Ruhiyuddin Mohd Zaki
    Barium titanate (BaTiO₃) is a perovskite based oxides with many potential application in electronic devices. From experimental report BaTiO₃ has wide energy band gap of about 3.4 eV which by doped with Ca and Zr at A-and B-sites respectively can enhance their piezoelectric properties. Using first principles method within the density functional theory (DFT) as implement in Quantum Espresso (QE) with the plane wave pseudo potential function, the influence of the Ca and Zr doping in BaTiO₃ are studied via electronic properties: band structure, total density of states (TDOS) and partial density of states (PDOS). The energy band gap calculated was underestimation which is similar to other DFT work. Two direct band gap where observed in Ba₀.₈₇₅Ca₀.₁₂₅Ti₀.₈₇₅Zr₀.₁₂₅O₃ sample at Γ-Γ (2.31 eV) and X-X (2.35 eV) symmetry point.
  • Publication
    The preliminary study of the addition Zinc in tin-copper lead free solder
    (Trans Tech Publications Ltd., 2020)
    Wei Yee Wong
    ;
    Rabiatul Adawiyah Shamsudin
    ;
    Muhammad Firdaus Mohd Nazeri
    ;
    Mohamad Najmi Masri
    Sn-0.7Cu lead free solder has become an alternative material to replace Sn-Pb solder. However, it has the weakness of high melting point and poor corrosion behavior. Through the study, Sn-0.7-xZn microstructure and phase changes were studied through scanning electron microscope (SEM) and X-ray diffraction (XRD). SEM result shows microstructure Cu6Sn5 is precipitated with rod like shape while CuZn is shown in bump oval shape whereas compounds that presented are Cu6Sn5 and Cu5Zn8 as shown in the XRD analysis result.
  • Publication
    The effect of Al micro-alloying on corrosion and thermal properties of Sn-Zn alloy
    (Trans Tech Publications Ltd., 2020)
    Nordarina Jumali
    ;
    Nurwahida Mohd Zaini
    ;
    Nur Syamira Sa'don
    ;
    Ahmad Azmin Mohamad
    ;
    Muhammad Firdaus Mohd Nazeri
    Electrochemical corrosion behavior of Sn–Zn solder alloys in 6 M potassium hydroxide solution was investigated by potentiodynamic polarization technique, aiming to investigate the role of Al additions. The effect of micro-alloying Al on the thermal properties was also studied by using DSC. The results reveal that the presence of Al content leads to increasing in corrosion potential yet reducing the corrosion current density and passivation current density, simultaneously. XRD analysis reveals the failure to produce new compound with Zn, limits the effect of adding Al towards the corrosion performance. Yet, significant improvement on thermal properties were seen, especially on the melting temperature and pasty range without modifying the eutectic melting behavior.