Search

This paper presents the isolation of kenaf bast fiber to produce cellulose nanofiber (CNF) using chemical-physical treatment (e.g. delignification, bleaching and ultrasonication). Raw bast fiber was bleached and then subjected to high-intensity ultrasonication at four different output powers (100 W, 200 W, 400 W and 700 W). SEM and TEM analysis of treated bast fiber revealed that the morphological structure of CNF with diameter distribution in the range less than 100 nm (100 W) to 10 nm (700 W). Hemicellulose and lignin content were successfully reduced by chemical treatments, as there was increment of the cellulose content in the fiber more than 90% recorded. Higher ultrasonication output power attributes to the decreasing diameter size of CNF. This finding reflected that smaller CNF fibrils provide larger surface area per volume ratio. Larger stretching vibration of – OH group is detected as the higher composition of cellulose in CNF. CNF produced also had higher thermal stability than raw bast fiber after undergoes the chemical-physical treatment. Therefore, chemical-physical treatment did not only to attribute the success of deposition of lignin and hemicellulose, but also to increase the nano-sized fiber distribution in CNF suspension.

Abstract The development of the Internet of Things (IoT) has produced new innovative solutions, such as smart cities, which enable humans to have a more efficient, convenient and smarter way of life. The Intelligent Transportation System (ITS) is part of several smart city applications where it enhances the processes of transportation and commutation. ITS aims to solve traffic problems, mainly traffic congestion. In recent years, new models and frameworks for predicting traffic flow have been rapidly developed to enhance the performance of traffic flow prediction, alongside the implementation of Artificial Intelligence (AI) methods such as machine learning (ML). To better understand how ML implementations can enhance traffic flow prediction, it is important to inclusively know the current research that has been conducted. The objective of this paper is to present a comprehensive and systematic review of the literature involving 39 articles published from 2016 onwards and extracted from four main databases: Scopus, ScienceDirect, SpringerLink and Taylor & Francis. The extracted information includes the gaps, approaches, evaluation methods, variables, datasets and results of each reviewed study based on the methodology and algorithms used for the purpose of predicting traffic flow. Based on our findings, the common and frequent machine learning techniques that have been applied for traffic flow prediction are Convolutional Neural Network and Long-Short Term Memory. The performance of their proposed techniques was compared with existing baseline models to determine their effectiveness. This paper is limited to certain literature pertaining to common databases. Through this limitation, the discussion is more focused on (and limited to) the techniques found on the list of reviewed articles. The aim of this paper is to provide a comprehensive understanding of the application of ML and DL techniques for improving traffic flow prediction, contributing to the betterment of ITS in smart cities. For future endeavours, experimental studies that apply the most used techniques in the articles reviewed in this study (such as CNN, LSTM or a combination of both techniques) can be accomplished to enhance traffic flow prediction. The results can be compared with baseline studies to determine the accuracy of these techniques.

Asthma is a chronic respiratory disease affecting more than 334 million people of all age groups globally. Although there are innumerable evidence-based guidelines and effective treatments for this disease, many patients with asthma still have uncontrolled symptoms. The effective control measures of chronic diseases primarily depend on the proper patient care in collaboration with healthcare providers. Currently, healthcare facilities are using the manual asthma action plan to customise each asthmatic patient to understand and manage asthma safely on their own. Thus, this article introduces a preliminary study of a digital health application prototype design based on the asthma action plan among adult asthma patients. The findings regarding the accessibility of this prototype among asthma patients will give a promising alternative tool to empower asthma patients to manage their asthma safely. [ABSTRACT FROM AUTHOR]

The global challenge of addressing oil spills in the ocean arises from their mobility and limited self-purification capacity, resulting in substantial and enduring harm to aquatic ecosystems and the depletion of valuable resources. Expanded graphite (EG) is a versatile and useful material that offers various unique properties and has many practical uses in industry and commerce, specifically in oil spill clean-up. This article provides a sulfur-free EG modified by palmitic acid (PA) / phosphoric acid (H3PO4). EG was synthesized by a two-step chemical oxidation process, with natural graphite flake (NGF) serving as the precursor. The chemical intercalation procedure was carried out at room temperature for 30 min in the first step "oxidation" with an optimum weight ratio of 1 g: 5.1 g: 18.8 g: 0.2 of NGF, PA, H3PO4, and KMnO4. Then, in the second step "intercalation", nitric acid, acetic acid, and potassium permanganate were utilized as assistant intercalating agents to further enhance the expanded volume of EG. FT-IR, XRD, and SEM were used to investigate the functional groups, structures, and morphology of the EG. The findings demonstrated that the interlayers within the natural flake graphite were completely opened and transformed into a structure resembling a fluffy rope, resembling the shape of a worm, upon expansion. Under optimal conditions, the maximum volume expansion achieved was 470 mL/g. The mesoporous expanded graphite, modified with PA/H3PO4, exhibits promise as an engineering material for water purification sorbents and also demonstrates a noteworthy oil sorption capacity. [ABSTRACT FROM AUTHOR]

Cenospheres are small, hard-shelled hollow spheres with high silica and alumina content. These micron-sized aluminosilicate hollow spheres constitute only a small percentage of the coal fly ash (CFA) obtained from the coal combustion processes. In this study, cenospheres were separated from CFA obtained from a coal-fired power plant located in Kapar, Malaysia. The cenospheres were heated at 1000, 1200 and 1400 °C to study the changes in morphologies, compositions, phase formation and thermal expansion. The sintering temperatures were selected based on the differential scanning calorimetry (DSC) curve results. X-ray diffractometry (XRD), field emission electron microscopy (FESEM), energy dispersive spectroscopy (EDS) as well as thermogravimetry and differential scanning calorimetry analysis (TG–DSC) were used for the characterization study. The study found that the cenospheres have excellent weight stability but are thermally unstable as a result of crystallization and melting. The phase ordering process and devitrification of the amorphous aluminosilicate glass phase at high temperatures lead to the increment and enrichment of the mullite phase in cenospheres. It is suggested that a preheating treatment at 1100 °C could be used to enhance the mechanical properties and thermally stabilize the cenospheres, which make it more suitable for use as a pore-forming agent in ceramics.

Mixture of aluminum dross (AD) and coal fly ash (CFA) was used to produce high-temperature porous mullite for washcoat application. CFA is the combustion by-product of pulverized coal in a coal-fired power plant, while AD is a waste product produced in secondary aluminum refining. In this study, 80 wt% of AD and 20 wt% of CFA was used to prepare a mullite precursor (MP) via acid leaching and dry-milling. The precursor was coated on a substrate and subsequently fired at 1500 °C. The results showed that the precursor transformed to a hierarchical porous microstructure assembled by large interlocked acicular mullite crystals. The pore structures consisted of large interconnected open pores and small pores. The specific surface area of the mullite washcoat was 4.85 m2g−1 after heating at 1500 °C for 4 h. The specific surface area was compatible with the specific surface area of other high-temperature washcoats.

Mycobacterium tuberculosis, the causing agent of tuberculosis, comes second only after HIV on the list of infectious agents slaughtering many worldwide. Due to the limitations behind the conventional detection methods, it is therefore critical to develop new sensitive sensing systems capable of quick detection of the infectious agent. In the present study, the surface modified cadmium-telluride quantum dots and gold nanoparticles conjunct with two specific oligonucleotides against early secretory antigenic target 6 were used to develop a sandwich-form fluorescence resonance energy transfer-based biosensor to detect M. tuberculosis complex and differentiate M. tuberculosis and M. bovis Bacille Calmette–Guerin simultaneously. The sensitivity and specificity of the newly developed biosensor were 94.2% and 86.6%, respectively, while the sensitivity and specificity of polymerase chain reaction and nested polymerase chain reaction were considerably lower, 74.2%, 73.3% and 82.8%, 80%, respectively. The detection limits of the sandwich-form fluorescence resonance energy transfer-based biosensor were far lower (10 fg) than those of the polymerase chain reaction and nested polymerase chain reaction (100 fg). Although the cost of the developed nanobiosensor was slightly higher than those of the polymerase chain reaction-based techniques, its unique advantages in terms of turnaround time, higher sensitivity and specificity, as well as a 10-fold lower detection limit would clearly recommend this test as a more appropriate and cost-effective tool for large scale operations. Keywords: Mycobacterium tuberculosis complex (MTBC), Cadmium-telluride quantum dots (CdTe-QDs), Gold nanoparticles (AuNPs), Fluorescence resonance energy transfer (FRET), Sandwich-form FRET-based biosensor

Nitrogen and phosphorus in wastewaters are a burning environmental issue of the present world. This review covers the studies conducted on the removal and recovery of phosphorus and nitrogen from wastewaters through struvite crystallization. Wastewater which contains a high amount of phosphorus and nitrogen would be a good source of struvite. Struvite is a phosphate fertilizer, although it contains a significant amount of nitrogen and magnesium, and it is an effective alternative source of rock phosphate to maintain the agricultural production system. The present review deals with the principles and concept of struvite nucleation, crystal growth and the factors that affect on the struvite quality. Struvite precipitation occurs in an equimolecular concentration of Mg2+,NH4+ andPO43− at slightly alkaline conditions. Addition of a source of Mg is essential to maintain the favorable condition of PO4 and Mg. Different factors such as Mg:PO4 molar ratio, pH, aeration rate, reactor types, as well as P and N removal efficiencies were also discussed throughout this review. The slower nutrient leaching loss and its fertilizer quality make struvite an eco-friendly fertilizer. It is possible to overcome the acute shortage of rock phosphate if all the municipal and livestock wastewaters are connected with the wastewater treatment plants.

Some industrial wastes are shown to be useful in the production of mullite ceramics. These industrial wastes are rich in certain metal oxides such as silica (SiO2) and alumina (Al2O3). This gives wastes the potential to be used as a starting material source for mullite ceramics preparation. The purpose of this review paper is to compile and review various mullite ceramics preparation methods that utilized a variety of industrial wastes as starting materials. This review also describes the sintering temperatures and chemical additives used in the preparation and its effects. A comparison of both mechanical strength and thermal expansion of the reported mullite ceramics prepared from various industrial wastes were also addressed in this work.