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Direct and catalyst-free synthesis of ZnO nanowires on brass by thermal oxidation

Arafat MM, Rozali S, Haseeb ASMA, Ibrahim S

Nanotechnology, 2020 Jan 09.
PMID: 31918416 DOI: 10.1088/1361-6528/ab69b3

In this research work, nanowires were grown on brass (Cu - 37.2 wt% Zn) substrate by thermal oxidation process. The substrate was oxidized at temperature ranging from 350-600 °C in the presence of varying concentrations of O2 in N2 (1-100%) flown at a rate of 200 sccm. The oxidized brass surface was characterized by field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray (EDX) spectroscope and transmission electron microscope (TEM). Four different types of morphological variations such as thin, thick with branches, circular-flake and flat-cone shape were observed during oxidation at different conditions. However, the prevalence of thin, thick morphology with branches was more prominent and found in all growth conditions. The length and diameter of the nanowires were varied from 1-30 µm and 50-500 nm, respectively whereas the length of the branches varied from 1-3 µm. The composition of the nanowires was ZnO possessing of hexagonal wurtzite structure. The selected area diffraction confirms that the nanowires grew along <1 1 0> directions. Based on the results, a stress induced based mechanism is proposed for the growth of ZnO nanowires on Cu - 37.2 wt% Zn substrate.
A review of microwave pyrolysis as a sustainable plastic waste management technique

Putra PHM, Rozali S, Patah MFA, Idris A

J Environ Manage, 2022 Feb 01;303:114240.
PMID: 34902653 DOI: 10.1016/j.jenvman.2021.114240

The high demand for plastic has led to plastic waste accumulation, improper disposal and environmental pollution. Even though some of this waste is recycled, most ends up in landfills or flows down rivers into the oceans. Therefore, researchers are now exploring better ways to solve the plastic waste management problem. From a socio-economic perspective, there is also a concerted effort to enable energy recovery from plastic waste and convert it into useful products to generate income for targeted segments of the population. In fact, this concept of waste-to-wealth has been adopted by the United Nations as part of its Sustainable Development Goals strategies. The current article begins by reviewing the strengths and weaknesses of plastic recycling before focusing specifically on microwave pyrolysis as an alternative to conventional technologies in plastic waste management, due to its benefit in providing fast and energy-efficient heating. The key parameters that are reviewed in this paper include different types of plastic, types of absorbent, temperatures, microwave power, residence time, and catalysts. The yield of the final product (oil, gaseous and char) varies depending on the main process parameters. Key challenges and limitations of microwave pyrolysis are also discussed in this paper.
Fulltext Synthesis of magnetic nanocarbon using palm oil as the green precursor via microwave-assisted arc for wastewater treatment

Zakaria NZJ, Rozali S, Mubarak NM, Khalid M

Sci Rep, 2022 Nov 04;12(1):18698.
PMID: 36333525 DOI: 10.1038/s41598-022-21982-y

The presence of metal with microwave irradiation has always invited controversial arguments as the metal will catch on fire easily. But interestingly, researchers found that arc discharge phenomena provide a promising way for molecule cracking to synthesize nanomaterials. This study developed a single-step yet affordable synthesis approach that combines microwave heating and arcing in transforming crude palm oil into magnetic nanocarbon (MNC), which can be considered a new alternative for the palm oil sectors. It involves synthesizing the medium at a partial inert condition with constant coiled stainless steel metal wire (dielectric media) and ferrocene (catalyst). This approach successfully demonstrates heating at a temperature ranging from 190.9 to 472.0 °C with different synthesis times (10-20 min). The produced MNC shows formations of spheres with average sizes of 20.38-31.04 nm, mesoporous structure (SBET: 14.83-151.95 m2/g), and high content of fixed carbon (52.79-71.24wt%), and the ratio of the D and G bands (ID/IG) is 0.98-0.99. The formation of new peaks in the FTIR spectra (522.29-588.48 cm-1) supports the appearance of the FeO compounds from the ferrocene. The magnetometer shows high magnetization saturation (22.32-26.84 emu/g) in ferromagnetic materials. The application of the MNC in wastewater treatment has been demonstrated by evaluating their adsorbent capability with Methylene Blue (MB) adsorption test at a different concentrations varying between 5 and 20 ppm. The MNC produced at synthesis time (20 min) shows the highest adsorption efficiency (10.36 mg/g) compared to others, with 87.79% removal of MB dye. As a result, the value for Langmuir is not promising compared to Freundlich, with R2 being around 0.80, 0.98, and 0.99 for MNC synthesized at 10 min (MNC10), 15 min (MNC15), and 20 min (MNC20), respectively. Hence, the adsorption system is in a heterogeneous condition. The microwave-assisted arcing thereby presents a promising approach to transforming CPO into MNC that could remove the hazardous dye.
Fulltext A review of the recent trend in the synthesis of carbon nanomaterials derived from oil palm by-product materials

Zakaria NZJ, Rozali S, Mubarak NM, Ibrahim S

Biomass Convers Biorefin, 2022 Feb 11.
PMID: 35194538 DOI: 10.1007/s13399-022-02430-3

Grown only in humid tropical conditions, the palm tree provides high-quality oil essential for cooking and personal care or biofuel in the energy sector. After the refining process, this demand could cause numerous oil palm biomass waste management problems. However, the emergence of carbon nanomaterials or CNMs could be a great way to put this waste to a good cause. The composition of the palm waste can be used as a green precursor or starting materials for synthesizing CNMs. Hence, this review paper summarizes the recent progress for the CNMs production for the past 10 years. This review paper extensively discusses the method for processing CNMs, chemical vapor deposition, pyrolysis, and microwave by the current synthesis method. The parameters and conditions of the synthesis are also analyzed. The application of the CNMs from palm oil and future recommendations are also highlighted. Generally, this paper could be a handy guide in assisting the researchers in exploring economic yet simple procedures in synthesizing carbon-based nanostructured materials derived from palm oil that can fulfill the required applications.
Growth of 1D TiO2nanostructures on Ti substrates incorporated with residual stress through humid oxidation and their characterizations

Arafat MM, Dinan B, Haseeb ASMA, Akbar SA, Rahman BMA, Rozali S, et al.

Nanotechnology, 2021 Sep 01;32(47).
PMID: 34388742 DOI: 10.1088/1361-6528/ac1d77

Different Ti substrates, such as particles (as-received and ball milled), plate and TEM grid were oxidized for the growth of one dimensional (1D) TiO2nanostructures. The Ti substrates were oxidized for 4 h at temperatures of 700 °C-750 °C in humid and dry Ar containing 5 ppm of O2. The effects of residual stress on the growth of 1D TiO2nanostructures were investigated. The residual stress inside the Ti particles was measured by XRD-sin2ψtechnique. The oxidized Ti substrates were characterized using field emission scanning electron microscope equipped with energy dispersive x-ray spectroscope, transmission electron microscope, x-ray diffractometer and x-ray photoelectron spectroscope. Results revealed that humid environment enhances the growth of 1D TiO2nanostructures. Four different types of 1D morphologies obtained during humid oxidation, e.g. stacked, ribbon, plateau and lamp-post shaped nanostructures. The presence of residual stress significantly enhances the density and coverage of 1D nanostructures. The as-grown TiO2nanostructures possess tetragonal rutile structure having length up to 10μm along the 〈1 0 1〉 directions. During initial stage of oxidation, a TiO2layer is formed on Ti substrate. Lower valence oxides (Ti3O5, Ti2O3and TiO) then form underneath the TiO2layer and induce stress at the interface of oxide layers. The induced stress plays significant role on the growth of 1D TiO2nanostructures. The induced stress is relaxed by creating new surfaces in the form of 1D TiO2nanostructures. A diffusion based model is proposed to explain the mechanism of 1D TiO2growth during humid oxidation of Ti. The 1D TiO2nanostructures and TiO2layer is formed by the interstitial diffusion of Ti4+ions to the surface and reacts with the surface adsorbed hydroxide ions (OH-). Lower valence oxides are formed at the metal-oxide interface by the reaction between diffused oxygen ions and Ti ions.
Evaluation of mandibular advancement surgery efficacy in treating obstructive sleep apnea: A study on turbulence kinetic energy

Latif MFA, Ghazali NNN, Rozali S, Badruddin IA, Kamangar S

Comput Methods Programs Biomed, 2025 Apr;261:108610.
PMID: 39919603 DOI: 10.1016/j.cmpb.2025.108610

BACKGROUND AND OBJECTIVE: Obstructive sleep apnoea (OSA) is a prevalent sleep disease characterised by recurrent airway obstruction during sleep, resulting in diminished oxygen intake and disrupted sleep patterns. This study investigates the effectiveness of mandibular advancement surgery as a surgical intervention for obstructive sleep apnoea by analysing the postoperative alterations in turbulence kinetic energy (TKE).
METHODOLOGY: The research involved five subjects receiving mandibular advancement surgery (MAS). The quantification of TKE was performed both before and throughout the method using a combination of computational fluid dynamics (CFD) models and empirical measurements. A suitable grid size of 2.6 million cells for CFD simulations was determined by grid sensitivity analysis and corroborated with physical measurements.
RESULTS: The findings indicated a significant increase in TKE for each individual post-procedure, with increments varying from 23 % to 460 %. The elevated TKE indicates a more rapid airflow in the upper airway post-surgery. This is probably attributable to alterations in the airway's morphology resulting from the surgery. The observed rise in speed and turbulence is theoretically supported by Bernoulli's principle, which elucidates the relationship between air flow velocity and the pressure it generates.
CONCLUSIONS: This study demonstrates that mandibular advancement surgery efficiently alleviates OSA by markedly enhancing airflow and diminishing turbulence in the upper airway post-treatment. The use of physical validation and grid sensitivity analysis in computational fluid dynamics simulations underscores the meticulous technique utilised, offering a comprehensive assessment of the efficacy of the surgical interventions for OSA.