25 research outputs found

    Three-dimensional rGO/CNT/g-C3N4 macro discs as an efficient peroxymonosulfate activator for catalytic degradation of sulfamethoxazole

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    Over the past few years, advanced oxidation processes (AOPs) have shown promising efficiencies for wastewater remediation. Carbocatalysis, in particular, has been exploited widely thanks to its sustainable and economical properties but has an issue of recovery and reusability of the catalysts. To address this, three-dimensional (3D) binary and ternary graphene-based composites in the form of macro discs were created to activate peroxymonosulfate (PMS) for catalytic oxidation of sulfamethoxazole (SMX). Graphene oxide served as the base, while graphitic carbon nitride (g-C3N4) and/or single-walled carbon nanotubes (SWCNTs) were added. Among the various discs synthesized, rGNTCN discs (ternary composite) were proven to be the most efficient by completely degrading SMX in 60 min owing to their large surface area and nitrogen loading. The catalytic system was further optimized by varying the reaction parameters, and selective radical quenching and electron paramagnetic resonance tests were performed to identify the active radical, revealing the synergistic role of both radical and non-radical pathways. This led to the development of possible SMX degradation pathways. This research not only provides insights into ternary carbocatalysis but also gives a novel breakthrough in catalyst recovery and reusability by transforming nanocatalysts into macro catalysts

    Wastewater remediation technologies using macroscopic graphene-based materials: A perspective

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    Three-dimensional (3D) graphene-based macrostructures are being developed to combat the issues associated with two-dimensional (2D) graphene materials in practical applications. The 3D macrostructures (3DMs), for example, membranes, fibres, sponges, beads, and mats, can be formed by the self-assembly of 2D graphene-based precursors with exceptional surface area and unique chemistry. With rational design, the 3D macrostructures can then possess outstanding properties and exclusive structures. Thanks to various advantages, these macrostructures are competing in a variety of applications with promising performances unlike the traditional activated carbons, biochars and hydrochars, which have less flexibilities for modifications towards versatile applications. However, despite having such a wide range of applications, 3DMs remain applicable on laboratory scale due to the associated factors like cost and extensive research. This perspective provides an overview of available graphene-based macrostructures and their diverse synthesis protocols. In the synthesis, hydrothermal route, chemical vapor deposition (CVD), wet spinning, 3D printing, vacuum filtration, spray drying and emulsion methods are highlighted. In addition, the physio-chemical properties of these macrostructures are discussed with the relationship among the porosity, surface area and the bulk density. The perspective also highlights the versatile potentials of different 3DMs in wastewater remediation by adsorption, desalination, and catalytic oxidation, etc. Following the concluding remarks, future outlooks on commercial applications of 3DMs are also provided

    Kajian tematik buah-buahan dalam Al-Quran dan penggunaannya untuk rawatan perubatan Islam

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    Intisari al-Quran menjelaskan persoalan aqidah, dan peraturan hidup berlandaskan syariah. Al-Quran juga menjelaskan kepelbagaian makanan yang menjadi keperluan manusia dan makhluk lain, termasuk pemakanan yang sihat melalui buah-buahan yang membawa manfaat kesihatan kepada tubuh manusia. Buah-buahan dalam al-Quran boleh dikenal pasti dengan nama-nama tertentu seperti At-Tin (Tin), Al-Zaitun (zaitun), Al-Talh (pisang) boleh merawat radang selaput dada, Inab (anggur), Al-Rumman (delima), A-Nakhl (kurma) mengurangkan kesakitan bayi selepas proses kelahiran, Al-Sidr (bidara) boleh merawat gangguan makhluk halus, dan Al-Habbah al Sawda (jintan hitam) boleh merawat segala-galanya kecuali kematian. Al-Qur’an bukan sahaja mukjizat bermakna yang dikurniakan kepada Rasulullah SAW, tetapi juga panduan rawatan rohani, jasmani dan ruqyah menggunakan ayat-ayat Al-Quran. Fokus kajian ini adalah untuk mengenal pasti tema buah-buahan dalam Al-Quran, manfaat kesihatan, pemilihan buah-buahan yang berkhasiat dan fungsi buah-buahan untuk rawatan perubatan Islam. Metodologi kajian menggunakan pendekatan kualitatif untuk mendapatkan maklumat saintifik dan menyemak dokumen seperti tesis, jurnal, buku dan temu bual. Pengkaji menggunakan rujukan tafsir Al-Quran untuk mengenal pasti buah-buahan yang sesuai untuk dijadikan herba perubatan. Berdasarkan kajian, pengkaji mendapati banyak khasiat dan khasiat buah-buahan yang disebut dalam Al-Quran sebagai ramuan herba, pengambilan buah-buahan yang bermanfaat untuk tubuh manusia. Kesimpulannya, kajian ini diharapkan dapat membuka minda masyarakat untuk menjaga kesihatan melalui pemakanan yang sihat dan menjadikan buah-buahan sebagai medium herba rawatan perubatan Islam

    The Effectiveness of Using Herb in Traditional Malay Medicine and Healthcare in Central Zone Community, Selangor

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    The use of herbs for medicinal purposes is essential. Herbal treatment had a positive impact on human life. Some people are too skeptical and lack confidence in the effectiveness of using herbs for treatment purposes. This situation occurs because the advancement of medical technology and modern medicine is more forward than traditional medicine. Herb-based treatment is still not able to provide traditional medicinal services that are conducive and comprehensive in terms of function, nutrients and comprehensive potential. The focus of this study is to expand knowledge by examining the effectiveness of herbs and treatment in human health care based on the 'Theory of Planned Behaviour' approach. The purpose of the study was to identify the types of herbs, analyze the response to the effectiveness of the use of herbs in health care based on traditional Malay medicinal methods. This research done based on qualitative and quantitative methods including literature review, library research, questionnaires and interviews. The results showed that traditional Malay medicine is a complete herbal treatment method and has strong fundamental values and is necessary in the science of medicine. Studies have also found the effectiveness of herbs in treating various types of physical and spiritual ailments. The findings proved that the use of various herbal plants is still relevant to treat diseases, contributing in the field of medical science just like existing modern medicine, especially in the issue of health care and a prosperous human life

    Adaptive neuro-fuzzy controller for grid voltage dip compensations of grid connected DFIG-WECS

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    This paper presents an adaptive neuro-fuzzy controller (NFC)to deal with grid voltage dip conditions for grid-connected operation of doubly fed induction generator (DFIG)driven wind energy conversion system (WECS). Due to the partial scale power converters, wind turbines based on DFIG are very sensitive to grid disturbances. Current saturation at the rotor side converter (RSC)and overvoltage at the dc-link are the major concerns of DFIG driven WECS during grid-voltage fluctuation. In synchronous reference frame, an oscillatory stator flux appears during voltage dip and it is difficult to suppress with conventional proportional-integral (PI)controllers considering nonlinear system dynamics. Therefore, an adaptive-network fuzzy inference system based NFC is proposed in this paper to handle the system uncertainties and minimize the effect of grid voltage fluctuations. During normal operation, the proposed controller aims to regulate the currents as demanded by the reference real and reactive power. Under voltage dip condition, the controllers adjust the positive sequence d-q axis current components both at the grid and rotor sides by supplying required reactive power to the grid. The negative sequence reference currents at rotor end actuate the demagnetization effect of minimizing the impact of voltage dips. The simulation results exhibit the proposed NFC performance through its robust control over the rotor side currents and bus voltage during both the voltage dip and normal operation

    Low spikes and low harmonic distortion multilevel inverter for induction motor implementation

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    Different Modulation techniques are suggested for use in electronic converters’ applications for getting minimized Total Harmonic Distortion (THD). One of such techniques a Selective Harmonics Elimination Pulse Width Modulation (SHE-PWM) scheme. Specific odd harmonics can be mitigated by operating the semiconductor switches in H-bridge inverters at optimized switching angles of the PWM signals. These switching angles are determined by calculating a set of nonlinear equations. Multilevel converters operated by PWM, suffer from the issue of harmonic spikes in the output voltage. In this paper, an improved scheme of SHE-PWM is proposed for multilevel converter to mitigate THD and supress the harmonic spikes of the system. To investigate and confirm the proposed technique, a five-level cascade multilevel inverter is simulated, and experimentally implemented. It is seen that the simulation results are verified experimentally by eliminating low- order harmoinics in getting a THD of 23.20% without using filter. The experimental results of the developed multilevel converer is validated with the simulation results under different performance conditions which show a complete agreement between them in terms of shapes and values
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