Showing papers by "Universiti Teknologi Petronas published in 2019"

Binary Optimization Using Hybrid Grey Wolf Optimization for Feature Selection

Abstract: A binary version of the hybrid grey wolf optimization (GWO) and particle swarm optimization (PSO) is proposed to solve feature selection problems in this paper. The original PSOGWO is a new hybrid optimization algorithm that benefits from the strengths of both GWO and PSO. Despite the superior performance, the original hybrid approach is appropriate for problems with a continuous search space. Feature selection, however, is a binary problem. Therefore, a binary version of hybrid PSOGWO called BGWOPSO is proposed to find the best feature subset. To find the best solutions, the wrapper-based method K-nearest neighbors classifier with Euclidean separation matric is utilized. For performance evaluation of the proposed binary algorithm, 18 standard benchmark datasets from UCI repository are employed. The results show that BGWOPSO significantly outperformed the binary GWO (BGWO), the binary PSO, the binary genetic algorithm, and the whale optimization algorithm with simulated annealing when using several performance measures including accuracy, selecting the best optimal features, and the computational time.

Fourth generation biofuel: a review on risks and mitigation strategies

Abstract: Fourth generation biofuel (FGB) uses genetically modified (GM) algae to enhance biofuel production. Although GM algae biofuel is a well-known alternative to fossil fuels, the potential environmental and health-related risks are still of great concern. An evaluation of these concerns and accordingly devising appropriate mitigation strategies to deal with them are important to a successful commercialized production of FGB. While extensive research has been carried out on genetic modification and other technologies that aim to increase the productivity of algae strains, only a handful of them deal with the legislative limitations imposed on exploiting and processing GM algae. This paper examines this legislation and the mitigation strategies to meet potential risks associated with the exploitation and processing of FGB. Open-pond system is an economic solution for large-scale cultivation of microalgae; however, the concern regarding the health and environmental risk of cultivating GM algae and the associated stringent regulations is considered as the main barrier of FGB production. Disposal of the residue is another important issue that should be considered in FGB production. The byproducts obtained from energy extraction step and residual water from the harvesting process may contain plasmid or chromosomal DNA that may cause the risk of lateral gene transfer. Hence an appropriate mitigation practices should be used for replacement of the hazardous water residue and by-products with more environmentally friendly alternatives. The results obtained from several field testing projects for open-environment exploitation of GM algae show that under the various conditions used, there was no apparent proof to support possible horizontal gene transfer in release of GM algae.

Insights into the microalgae cultivation technology and harvesting process for biofuel production: A review

Abstract: Derivation of biofuel from microalgae biomass has been widely researched in the past few decades. Microalgae is capable of producing 58,700 litres oil per hectare that can generate 121,104 litres biodiesel per hectare, which seemingly a promising transition over conventional fossil fuels. Nevertheless, economic sustainability of commercial scale production of microalgae biomass is still in shadows of doubt, especially the cultivation and harvesting process. Apparently, the microalgae cultivation system has evolved from traditional open pond to various modern photobioreactor (PBR) designs. However, with regards to tubular and flat panel PBRs as the most ubiquitous systems for biofuel production at commercial level, extensive discussion on reactor configurations and design betterment was presented in this review, along with precise technical comparison on cost and energy requirements for the cultivation systems. This review intended to serve as guideline for long term adoption of these well-established cultivation technologies in biofuel plants given the numerous economic benefits. Besides that, in attempt to lower the harvesting cost, potential use of various waste biomass as bioflocculants to recover microalgae biomass was introduced in this review. This article also deliberates direction on potential policy interventions to produce microalgae biofuel in a more sustainable and cost-effective manners in near future.

Microwave vacuum pyrolysis of waste plastic and used cooking oil for simultaneous waste reduction and sustainable energy conversion: Recovery of cleaner liquid fuel and techno-economic analysis

Abstract: Microwave vacuum pyrolysis was examined and compared to conventional pyrolysis for its technical and economic feasibility in co-processing of waste plastic and used cooking oil simultaneously to generate fuel product. The pyrolysis demonstrated beneficial process features with respect to high heating rate (29 °C/min) to provide fast heating, high process temperature for extensive cracking (581 °C), short process time (20 min), and low electrical energy consumption (0.38 kWh). The combined use of microwave vacuum pyrolysis and activated carbon reaction bed produced up to 84 wt% yield of liquid oil, containing light hydrocarbons and higher heating value (49 MJ/kg) than diesel and gasoline, hence showing great promise for application as fuel. The use of activated carbon reaction bed showed beneficial effect in creating a reduction environment that prevented the oxidation or formation of oxygenated by-products. A positive synergistic effect between waste plastic and used cooking oil was also observed. The liquid oil obtained from this pyrolysis approach presented a low oxygen and nitrogen content, and free of sulphur, showing ‘cleaner’ properties with respect to reduced char residues, sludge formation, corrosiveness, degradation of oil quality, and emission of undesired SOx and NOx during its utilization in combustion process. The techno-economic analysis indicated that this pyrolysis approach showed low production cost (USD 0.25/L compared to USD 0.523/L of diesel price in Malaysia). Our results demonstrate that microwave vacuum pyrolysis is potentially economically feasible and show promise as a sustainable approach for energy conversion in providing improved process features and production of cleaner liquid fuel.

Incorporation of waste materials in the manufacture of masonry bricks: An update review

Abstract: Conventional bricks are made off from clay with high firing temperature or from cement concrete, but these consume and emit high energy and have environment shortcoming like carbon footprint and raw materials depletion. Researchers have utilized various types of waste materials in the production of bricks to protect the environment and contribute towards sustainable development. This study presents the latest research updates on utilizing waste materials in bricks manufacturing. The study categorized into two groups based on manufacturing method: fired and unfired methods. The review of literature exhibited an obvious potential of the waste materials as partial or total replacement of conventional raw materials where the produced bricks fulfilled the standards requirements. Additional research work is required, not just in the properties and economical parts but also on educating and aware the public about the advantages of utilizing waste materials in bricks manufacturing as well as on developing codes of practices and standards. © 2018 Elsevier Ltd

Recent developments on heterogeneous catalytic CO2 reduction to methanol

Abstract: Catalytic reduction of carbon dioxide to methanol is an attractive option to reduce concentration of greenhouse gas and generation of renewable energy. Moreover, depletion of fossil fuel, global warming and steep hikes in the price of fuels are the key driving factor to investigate methanol synthesis by CO2 hydrogenation. In the last few decades, several investigations on catalytic CO2 hydrogenation to methanol have been reported in the literature. This article deals with a comprehensive review of all the recent studies conducted during the past decades. Furthermore, different aspects of the reaction system such as thermodynamic constrains, catalysts formulation, reactors aspects, reaction mechanism and influences of reaction conditions are discussed in detail. By now, such a discussion is still missing, and we intend to close this gap in this paper. The current scenario demonstrates the existence of immense prospects and opportunities to investigate further in this area.

Hybrid carbon fiber-carbon nanotubes reinforced polymer composites: A review

Abstract: As a result of its impressive 3D network structure form, a great deal of interest has thus been generated among the science community on the hybridization of carbon fiber (CF) and carbon nanotube (CNT). Although there had been a large amount of studies conducted on this novel hybrid material, there are however, limited reviews being published on their fabrication methods and performances in polymer composites. For this reason, apart from collectively introducing and discussing the advantages and limitations of the hybrid CF-CNT based on various fabrication methods such as those of chemical vapour deposition, electrophoretic deposition, electrospray deposition and chemical functionalization, this study had also examined and compared the detailed performances of each of the hybrid CF-CNT reinforced polymer composite based on their fabrication methods through its mechanical, electrical and thermal properties.

Treatment technologies of palm oil mill effluent (POME) and olive mill wastewater (OMW): A brief review

Abstract: Attributable to the enormous population growth, tonnes of effluents are unavoidably generated throughout the agricultural activities. The inadequate effluents disposal induces perpetual contamination to the sea and river water sources, which has subsequently raised the public environmental concern. For that reason, the handling protocol of agricultural effluents was flagged up as an interest area for research. Despite the environmental hazards, agricultural effluents have the potential to be transformed from wastes into wealth via biological, physicochemical, thermochemical or a combination of processes thereof. The identical characteristics of palm oil mill effluent (POME) and olive mill wastewater (OMW) render the possibility of treating these wastes using the similar treatment method. Generally, biological treatment requires a longer process time compared to physicochemical and thermochemical technologies despite its easy and low-cost operation. Comparatively, physicochemical and thermochemical methods extend their potentiality in converting the agricultural effluents into higher value products more efficiently. This paper reviews the source and characteristics of both POME and OMW. Subsequently, a comparison of the current and alternative treatments for both effluents was done before the future perspectives of both effluents’ treatment are paved based on the well-being of the human, environment, and economic.

Transformation of Biomass Waste into Sustainable Organic Fertilizers

Abstract: The management of solid waste presents a challenge for developing countries as the generation of waste is increasing at a rapid and alarming rate. Much awareness towards the sustainability and technological advances for solid waste management has been implemented to reduce the generation of unnecessary waste. The recycling of this waste is being applied to produce valuable organic matter, which can be used as fertilizers or amendments to improve the soil structure. This review studies the sustainable transformation of various types of biomass waste such as animal manure, sewage sludge, municipal solid waste, and food waste, into organic fertilizers and their impact on waste minimization and agricultural enhancement. The side effects of these organic fertilizers towards the soil are evaluated as the characteristics of these fertilizers will differ depending on the types of waste used, in addition to the varying chemical composition of the organic fertilizers. This work will provide an insight to the potential management of biomass waste to be produced into organic fertilizer and the advantages of substituting chemical fertilizer with organic fertilizer derived from the biomass waste.

Modelling and optimization of photocatalytic degradation of phenol via TiO2 nanoparticles: An insight into response surface methodology and artificial neural network

Abstract: The epidemic growth of the pharmaceuticals industries over the years in order to meet the human demands had exerted substantial pressure on the global environment, particularly water pollutions crisis. Herein, the photocatalytic degradation of phenol was investigated via commercial TiO2 nanoparticles. The Artificial Neural Network (ANN) and Response Surface Methodology (RSM) was employed for scrutinizing the suitable modelling and optimized condition of the TiO2 nanoparticles in yielding a profound rate of phenol removal. The parameters of investigation involved pH, phenol concentration, catalyst doses and degradation time. The RSM data shows the profound rate of phenol removal ˜ 99.48% was achieved by TiO2 NPs in a designed photocatalytic system that set at 5.42 pH, 15.21 mg/L phenol concentration, 1.75 g/L TiO2 dosage and 540 min irradiation time. The designed system fits well with the Pseudo-First-Order and the Langmuir isotherm model with R2 > 0.999. On the other hand, the ANN study revealed that the predicated model was perfectly fitted with the experimental data giving the highest value of R2. This work provides an insight into two different statistical modelling and optimization which could provide exposure for developing an optimized nanomaterial towards the removal of hazardous pollutant.

A state-of-the-art review on facilitating sustainable agriculture through green fertilizer technology adoption: Assessing farmers behavior

Abstract: Green technology is the means of improving towards the rising environmental concern. The implication of green fertilizer technology (GFT) is the need for the modern development of environmentally friendly technology, also to increase the production level among all the agriculture crops. It is especially needed for paddy production, as it has always been considered as an important commodity because it is the main staple food for the nation. Paddy production in Malaysia using GFT allows for sustainable development and boosts the yield. Nevertheless, the adoption rate of GFT is unsatisfactory in most of the developing countries, including in Malaysia. The fact that the cost of production is considerably higher results in low-level perception regarding the adoption of GFT. Hence, the integration of communication and technology factors could become one of the main elements for the further development of the paddy sector in Malaysia. The overall objective of this research study will identify the factors that determine paddy farmer's adoption decision on GFT in Malaysia. To do so, a literature review was compiled on the topic of agriculture innovation-based adoption decision theories such as Diffusion of innovation (DOI), Theory of reasoned action (TRA), Theory of Planned Behavior (TPB) and Technology acceptance model (TAM) and communication channels to study paddy farmers' adoption decision of GFT. The results of the review revealed that this framework highlights adoption as an intricate behavior, interweaving aspects such as communication channels, socio-psychological and innovation attribute considerations. The conceptual framework illuminates the decision towards adoption as a self-motivated process, assumes a composite interaction among groups of variables coming from two different theories. The combination of DOI, TRA, TPB, TAM and communication channels overcome some limitations that arise when the only theory is used to examine the adoption decision among paddy farmers in Malaysia. Correspondingly, there has been limited empirical research done on the decision of adoption toward GFT use among paddy farmers in Malaysia.

Recent advances in the pretreatment of lignocellulosic biomass for biofuels and value-added products

Abstract: Many countries in the world aim to achieve sustainable development goals by 2030 following ambitious climate change mitigation, and thus, the concept of sustainable biorefinery has attracted immense research and development around the world. The concept of the biorefinery is centrally based on the conversion of biomass into biofuels and value-added products. Nevertheless, lowering the recalcitrance of the lignocellulosic matrix in a cost-effective and environmentally benign manner is a crucial pretreatment step. Different pretreatment methods have been categorized as physical, chemical, biological, physicochemical, and combined. Recently, some novel ionic liquids have also emerged as promising sustainable pretreatment solutions for use of lignocellulosic waste on a large scale. This review briefly presents recent findings on the pretreatment for the conversion of lignocellulosic materials into fuel and value-added products.