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Siti Fairus Asahar,Khasnur Abd Malek,Wan Najwa Wan Mohd Zohdi,Alan Basil Peter 대한가정의학회 2020 Korean Journal of Family Medicine Vol.41 No.1
We present the case of a 14-year-old Malay girl with an ependymoma of the conus medullaris who presented to multiple general practitioner clinics with a 24-month history of chronic low back pain. The pain was symptomatically managed as a simple musculoskeletal pain and sciatica. Further imaging to aid diagnosis was delayed until the appearance of severe pain with neurological deficits. Magnetic resonance imaging revealed an enhancing spinal mass at L1 through L3, and histopathological investigations confirmed the grade II ependymoma according to the World Health Organization classification. She underwent gross resection of the tumor. After the surgery, she developed neurogenic urinary bladder and bowel, which required intermittent self-catheterization, intermittent enema use, and intensive physical therapy.
Zainal Muhammad Thalhah,Mohd Yasin Mohd Fairus,Wan Ali Wan Fahmin Faiz,Tamrin Khairul Fikri,Ani Mohd Hanafi 한국탄소학회 2020 Carbon Letters Vol.30 No.5
Although fame synthesis promises economic beneft and rapid synthesis of carbon nanotube (CNT), the lack of control and understanding of the efects of fame parameters (e.g., temperature and precursor composition) impose some challenges in modelling and identifying CNT growth region for obtaining better throughput. The present study presents an investigation on the types of carbon precursor that afect CNT growth region on nickel catalyst particles in an ethylene inverse difusion fame. An established CNT growth rate model that describes physical growth of CNT is utilised to predict CNT length and growth region using empirical inputs of fame temperature and species composition from the literature. Two variations of the model are employed to determine the dominant precursor for CNT growth which are the constant adsorption activation energy (CAAE) model and the varying adsorption activation energy (VAAE) model. The carbon precursors investigated include ethylene, acetylene, and carbon monoxide as base precursors and all possible combinations of the base precursors. In the CAAE model, the activation energy for adsorption of carbon precursor species on catalyst surface Ea,1 is held constant whereas in the VAAE model, Ea,1 is varied based on the investigated precursor. The sensitivity of the growth rate model is demonstrated by comparing the shifting of predicted growth regions between the CAAE model and the VAAE model where the CAAE model serves as a control case. Midpoint-based and threshold-based techniques are employed within each model to quantify the predicted CNT growth region. Growth region prediction based on the midpoint-VAAE approach demonstrates the importance of acetylene and carbon monoxide to some extent towards CNT growth. Ultimately, the threshold-VAAE model shows that the dominant precursor for CNT growth is the mixture of acetylene and carbon monoxide. A simplifed reaction mechanism is proposed to describe the surface chemistry for precursor reactions with nickel catalyst where decomposition of the ethylene fuel source into acetylene and carbon monoxide is accounted for by chemisorption.
Hydrogenation of Liquid Natural Rubber Using 2,4,6-Trimethylbenzenesulfonylhydrazide
Mohamad Shahrul Fizree Idris,Hamizah Md Rasid,Fazira Firdaus,Siti Fairus M. Yusoff 한국고분자학회 2018 폴리머 Vol.42 No.4
Hydrogenation of liquid natural rubber (LNR) using 2,4,6-trimethylbenzenesulfonylhydrazide (MSH) in toluene was studied. HLNR structure was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). Response surface methodology (RSM) based on 5-level-2-factor central composite rotatable design (CCRD) was used to analyze the correlative effects of reaction, MSH:LNR weight ratio (0.5-1.0) and reaction time (20-60 min) with a fixed reaction temperature of 100 ºC. Multivariate statistical analysis was developed in a form of quadratic model in order to correlate the reaction parameter to the response received. The optimum conditions derived via RSM were the MSH:LNR weight ratio of 0.7 and a reaction time of 25.86 min. The R2 value of 0.9557 showed that the model was well-fitted with the experimental data, whereby the model was almost ideal while the lack-of-fit considered rather unseemly (i.e. insignificant).
Mhonishya Krishnamoorthy,Mohamad Azuwa Mohamed,Noor Haida Mohd Kaus,Siti Fairus M. Yusoff 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-
A hydrogel-based photocatalyst was employed to remove methylene blue (MB) and safranin dye effluentsfrom wastewater using a liquid natural rubber (LNR)-acrylic acid (AAc) based bismuth ferrite (BFO)hydrogel compound. Response Surface Methodology (RSM) was used in this research to optimize severalparameters for the synthesis of hydrogel compound and adsorptive-photodegradation process. Without apost-treatment separation phase, safranin and MB dye were able to maintain dye removal for up to sixand five cycles with 99% dye removal, respectively, explaining the hydrogel’s stability and adsorptive efficiency. Furthermore, MB and safranin dyes were adsorbed and photodegraded very rapidly under a xenonlamp compared to the dye removal efficacy at dark, proving BFO has aided in the photodegradation processadsorbs further the dye effluents in which the hydroxyl radical (·OH) and superoxide radical (·O2 – )species were responsible for the photocatalytic activity. It has been proposed that safranin and MB dyeeffluent adsorption matches the pseudo-second-order kinetic model and Freundlich isotherm model. Apositive entropy number, S, in thermodynamic analysis indicates that the reaction has become more random,boosting the system’s spontaneity. Meanwhile, it is found that adsorption rate of safranin is highlydependent on pH and is under the influence of inner sphere surface complexes. Thus, the synthesizedLNR-g-MaH/AAc-BFO hydrogel compound in this study has shown excellent performance in the removalof dye effluents for the wastewater treatment process with enhanced stability.
Hamizah Md Rasid,Nur Hanis Adila Azhar,Naharullah Jamaluddin,Siti Fairus M. Yusoff 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.6
This article reports an efficient, mild-temperature method for the hydrogenation of liquid natural rubber (LNR). The hydrogenation of LNR was studied using diimide generated in situ from the thermolysis of 2,4,6-trimethylbenzenesulfonyl hydrazide (MSH) in o-xylene at 100°C. The effects of reaction temperature, reaction time, solvent, and MSH/LNR weight ratio on the percentage of hydrogenation were evaluated.1H NMR analysis revealed that ~80% hydrogenation was achieved with a weight ratio of MSH:LNR = 1:1 at 100°C in o-xylene within 60 min.
Emerging polymeric-based material with photocatalytic functionality for sustainable technologies
Nur Shamimie Nadzwin Hasnan,Mohamad Azuwa Mohamed,Nornastasha Azida Anuar,Muhamad Firdaus Abdul Sukur,Siti Fairus Mohd Yusoff,Wan Nur Aini Wan Mokhtar,Zul Adlan Mohd Hir,Norshahidatul Akmar Mohd Shoha 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-
A variety of polymer-based photocatalysts for the highest photocatalytic activity through various modificationsand improvements such as doping, treatment with the oxidising or reducing agent, and integratinganother nanomaterial into the polymer photocatalysts composite are extensively studied. Furthermore, the most common issues on polymer-based photocatalysts, including wide band gap andhigh recombination rate of charge carriers, still need to be improved to yield high photocatalytic activity. Besides hydrogen evolution through the water splitting system, focus also has been paid to photocatalyticfor CO2 reduction, photodegradation of pollutants, photocatalytic chemical synthesis, and photocatalyticnitrogen fixation. This review attempts to reveal the secret of properties, issues, and enhancements, principallyin polymer photocatalysts, besides highlighting the reason for polymeric material as a critical nonmetal-based photocatalyst for various photocatalytic reactions, as well as conducting polymeric materialwith photocatalytic functionality.
Muhammad Thalhah Zainal,Norikhwan Hamzah,Mazlan Abdul Wahid,Natrah Kamaruzaman,Cheng Tung Chong,Mohd Hanafi Ani,Shokri Amzin,Tarit Das,Mohd Fairus Mohd Yasin 한국탄소학회 2023 Carbon Letters Vol.33 No.7
The conventional multi-scale modelling approach that predicts carbon nanotube (CNT) growth region in heterogeneous flame environment is computationally exhaustive. Thus, the present study is the first attempt to develop a zero-dimensional model based on existing multi-scale model where mixture fraction z and the stoichiometric mixture fraction zst are employed to correlate burner operating conditions and CNT growth region for diffusion flames. Baseline flame models for inverse and normal diffusion flames are first established with satisfactory validation of the flame temperature and growth region prediction at various operating conditions. Prior to developing the correlation, investigation on the effects of zst on CNT growth region is carried out for 17 flame conditions with zst of 0.05 to 0.31. The developed correlation indicates linear ( zlb=1.54zst +0.11) and quadratic ( zhb=zst(7-13zst )) models for the zlb and zhb corresponding to the low and high boundaries of mixture fraction, respectively, where both parameters dictate the range of CNT growth rate (GR) in the mixture fraction space. Based on the developed correlations, the CNT growth in mixture fraction space is optimum in the flame with medium-range zst conditions between 0.15 and 0.25. The stronger relationship between growth-region mixture-fraction (GRMF) and zst at the near field region close to the flame sheet compared to that of the far field region away from the flame sheet is due to the higher temperature gradient at the former region compared to that of the latter region. The developed models also reveal three distinct regions that are early expansion, optimum, and reduction of GRMF at varying zst.