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Anaerobic digestion (AD) from organic waste has gained worldwide attention because it offers significant environmental and economic benefits. It can reduce the local waste through recycling which will conserve resources, reduce greenhouse gas emissions, and build economic resilience in the face of an uncertain future for energy production and waste disposal. The productive use of local waste through recycling conserves resources by reducing landfill space, the whole of life impacts of landfilling, and post-closure maintenance of landfills. Turning waste into a renewable energy source will assist the decarbonisation of the economy by reducing harmful emissions and pollutants. Therefore, this mini-review aims to summarise key factors and present valuable evidence for an efficient AD process. It also presents the pros and cons of different AD process to convert organic waste along with the reactor technologies. Besides, this paper highlights the challenges and the future perspective of the AD process. However, it is highlighted that for an effective and efficient AD process, appropriate temperature, pH, a strong inoculum to substrate ratio, good mixing and small particle sizes are important factors. The selection of suitable AD process and reactor is important because not all types of processes and reactors are not effective for processing organic waste. This study is of great importance for ongoing work on renewable energy generation from waste and provides important knowledge of innovative waste processing. Finally, it is recommended that the government should increase their support towards the AD technology and consider the unutilized significant potential of gaseous biofuel production. [ABSTRACT FROM AUTHOR]

Engineering education providers should foresee the potential of digital transformation of teaching and skill-developing activities so that graduating engineers can find themselves highly aligned with the demands and attributes needed by prospective industrial employers. The advancement of industrial revolutions towards hybridisation of the enabling technologies recognised by Industry 4.0, Society 5.0, and Industry 5.0 have transformed the components of the engineering higher education system remarkably. Future workforce requirements will demand an employee's multidisciplinary skill mix and other professional qualities. Implementing human-centric decision-making based on insights from the Digital Twin (DT) systems, sustainability, and lean systems is necessary for further economic growth. Recent barriers identified by the Australian Council of Engineering Deans, the development of teaching capabilities, and affordable and digitally transformed learning facilities by education providers were all considered. This paper explores the role of Digital Twins (DTs) in enhancing engineering higher education by incorporating Industry 4.0 components and other industrial advances. By reviewing curricula, pedagogy, and the evolving skill requirements for engineering graduates, this study identifies key benefits of DTs, such as cost-effectiveness, resource management, and immersive learning experiences. This paper also outlines challenges in implementing DT-based labs, including IT infrastructure, data quality, privacy, and security issues. The findings indicate that engineering education should embrace DTs to foster multidisciplinary skills and human-centric decision-making to meet future workforce demands. Collaboration with industry is highlighted as a crucial factor in the successful transformation of teaching practices and in offering real-world experiences. The COVID-19 pandemic has expedited the adoption of DT technologies, demonstrating their utility in minimising educational disruptions. While this paper acknowledges the high potential of DTs to prepare engineering students for future industry demands, it also emphasises the need for professional development among educators to ensure effective and balanced implementation. [ABSTRACT FROM AUTHOR]

Ultra-low sulfur diesel fuel is essential requirement as per the emission regulation. With the adoption of hydrodesulfurization (HDS) process, the diesel fuel loses its inherent lubricity, however certain amount of lubricity of diesel fuel is needed to save several engine components from wear and failure. Though the loss of lubricity of the diesel fuel is observed with the removal of sulfur, it is mainly due to the loss of nitrogen and oxygen based polar trace compounds which are also removed in the HDS process. Unrefined biodiesels having little amount of monoglycerides (<0.8%) and free fatty acids also show better lubricity and fuel properties to be used as fuel lubricant. Biodiesel are also considered as the suitable blending compound with the diesel. This study found that the biodiesel blends up to 20% with the diesel fuel can effectively reduce both the wear of the tribo-contact surfaces as well as the friction coefficient. The use of biodegradable fuel lubricant has set away the threat of environment pollution by the diesel additives which are derived chemically. The oxidation stability and the low temperature properties of both the biodiesel and the vegetable oils can be improved with some chemical modification. It can be concluded that the use of biodiesel with the diesel fuel can be an appropriate option for effective engine lubrication system where only the fuel has to provide the required lubricity. [ABSTRACT FROM AUTHOR]

This paper examines the performance and emission characteristics of biodiesel produced from edible oil source (palm) and non-edible oil source (Jatropha) and compared that with fossil diesel fuel. Only 20% palm and 20% Jatropha biodiesel (described by PB20 and JB20 respectively) were examined because it has been suggested by the commercial company that up to 20% biodiesel can be used in a diesel engine without any engine modification. The physical and chemical properties of PB20 & JB20 are also presented and compared with diesel fuel (B0). The performance of these fuels and their emissions were measured in a multi-cylinder diesel engine at different engine speeds and at full load condition. The test results indicated that both PB20 and JB20 fuels produces slightly lower brake powers and higher brake specific fuel consumption compared to diesel fuel. Engine emission results indicated that the PB20 and JB20 fuel reduces the average emissions of carbon monoxide (CO) and hydrocarbons (HC). However, the PB20 and JB20 fuels slightly increases nitric oxides (NO) emissions compared to diesel fuel. Although PB20 have slightly better emission performance than JB20 biodiesel, JB20 biodiesel should be used in unmodified diesel engines to meet the global energy demand and to reduce emissions into the atmosphere because it does not create food versus fuel conflict. [ABSTRACT FROM AUTHOR]

There are concerns that biodiesel feedstock may compete with food supply in the long term, if the raw materials are vegetable virgin oils only. Therefore, throughout the world, large amounts of non-edible oil plants are available in nature. In this paper, experimental study has been carried out to analyze engine performance and emission characteristics for direct injection diesel engine using biodiesel obtained from non-edible oil such as jatropha oil and was blended with diesel fuel (DF) by 5% (JB5), 10% (JB10), 15% (JB15) and 20% (JB20) volumetrically without any engine modifications. Due to the presence of molecular oxygen, biodiesel undergoes improved combustion in the engine and has less polluting emissions in comparison with normal diesel fuels. Engine performance test was performed at 100% load keeping throttle 100% wide open with variable speeds of 1500 to 2400 rpm at an interval of 100 rpm. Whereas, emission tests were carried out at 2300 rpm at 100% and 80% throttle position. As results of investigations, there has been a decrease in torque and brake power, while increase in specific fuel consumption (sfc) has been observed for all biodiesel blend fuels over the entire speed range compared to DF. In case of engine exhaust gas emissions, reduction in HC, CO and CO2 were found for all blends. Besides, sound level for blend fuels was also reduced compared to DF. It can be concluded that jatropha biodiesel blend fuels can be used in diesel engines without any engine modifications and have beneficial effects both in terms of emission reductions and alternative petroleum diesel fuel. [ABSTRACT FROM AUTHOR]