89 research outputs found
Graphene synthesis techniques and environmental applications
Graphene is fundamentally a two-dimensional material with extraordinary optical, thermal, mechanical, and electrical characteristics. It has a versatile surface chemistry and large surface area. It is a carbon nanomaterial, which comprises sp2 hybridized carbon atoms placed in a hexagonal lattice with one-atom thickness, giving it a two-dimensional structure. A large number of synthesis techniques including epitaxial growth, liquid phase exfoliation, electrochemical exfoliation, mechanical exfoliation, and chemical vapor deposition are used for the synthesis of graphene. Graphene prepared using different techniques can have a number of benefits and deficiencies depending on its application. This study provides a summary of graphene preparation techniques and critically assesses the use of graphene, its derivates, and composites in environmental applications. These applications include the use of graphene as membrane material for the detoxication and purification of water, active material for gas sensing, heavy metal ions detection, and CO2 conversion. Furthermore, a trend analysis of both synthesis techniques and environmental applications of graphene has been performed by extracting and analyzing Scopus data from the past ten years. Finally, conclusions and outlook are provided to address the residual challenges related to the synthesis of the material and its use for environmental applications
Energy Storage for Water Desalination Systems Based on Renewable Energy Resources
Recently, water desalination (WD) has been required for the supply of drinking water in a number of countries. Various technologies of WD utilize considerable thermal and/or electrical energies for removing undesirable salts. Desalination systems now rely on renewable energy resources (RERs) such as geothermal, solar, tidal, wind power, etc. The intermittent nature and changeable intensity constrain the wide applications of renewable energy, so the combination of energy storage systems (ESSs) with WD in many locations has been introduced. Thermal energy storage (TES) needs a convenient medium for storing and hence reuses energy. The present work provides a good background on the methods and technologies of WD. Furthermore, the concepts of both thermal and electrical energy storage are presented. In addition, a detailed review of employing ESSs in various WD processes driven by RERs is presented. The integration of energy storage with water desalination systems (WDSs) based on renewable energy has a much better capability, economically and environmentally, compared with conventional desalination systems. The ESSs are required to guarantee a constant supply of fresh water over the day
Concentrating solar power (CSP) technologies: Status and analysis
Concentrated solar power (CSP) technology is a promising renewable energy technology worldwide. However, many challenges facing this technology nowadays. These challenges are mentioned in this review study. For the first time, this work summarized and compared around 143 CSP projects worldwide in terms of status, capacity, concentrator technologies, land use factor, efficiency, country and many other factors. Further, the various challenges facing the spread-out of this system are highlighted in terms of the heat transfer fluids (HTF), various energy storage (ES) technologies, cooling techniques, water management, and the Levelized Cost of Electricity (LCOE). Also, various thermophysical properties of the HTF are compared within the applicable range of the CSP operation. At the end of the review, various hybridization technologies for the CSP with various renewable energy sources, including photovoltaic, wind, and geothermal, are highlighted and compared. The pioneering country in using CSP, leading concentrator technology, suitable ES technology, and efficient hybrid technique based on the LCOE are determined. The analyzed data in this study is essential for predicting the future of the CSP in the markets and its contribution to reducing global warming potential
Renewable Energy and Energy Storage Systems
The use of fossil fuels has contributed to climate change and global warming, which has led to a growing need for renewable and ecologically friendly alternatives to these. It is accepted that renewable energy sources are the ideal option to substitute fossil fuels in the near future. Significant progress has been made to produce renewable energy sources with acceptable prices at a commercial scale, such as solar, wind, and biomass energies. This success has been due to technological advances that can use renewable energy sources effectively at lower prices. More work is needed to maximize the capacity of renewable energy sources with a focus on their dispatchability, where the function of storage is considered crucial. Furthermore, hybrid renewable energy systems are needed with good energy management to balance the various renewable energy sources’ production/consumption/storage. This work covers the progress done in the main renewable energy sources at a commercial scale, including solar, wind, biomass, and hybrid renewable energy sources. Moreover, energy management between the various renewable energy sources and storage systems is discussed. Finally, this work discusses the recent progress in green hydrogen production and fuel cells that could pave the way for commercial usage of renewable energy in a wide range of applications
A new cytotoxic carbazole alkaloid from Clausena excavata
A new carbazole alkaloid, 3-carbomethoxy-2-hydroxy-7-methoxycarbazole, Clausine-TY (1),together with two known carbazole alkaloid, Clausine-H (2) and Clausine-B (3), were isolated from the ethyl acetate extract of the stem bark of the Malaysian Clausena excavata. The structures of these compounds were elucidated by spectroscopic analyses. The new carbazole alkaloid shows significant cytotoxicity against CEM-SS cell line
State-of-the-art technologies for building-integrated photovoltaic systems
Advances in building-integrated photovoltaic (BIPV) systems for residential and commercial purposes are set to minimize overall energy requirements and associated greenhouse gas emissions. The BIPV design considerations entail energy infrastructure, pertinent renewable energy sources, and energy efficiency provisions. In this work, the performance of roof/façade-based BIPV systems and the affecting parameters on cooling/heating loads of buildings are reviewed. Moreover, this work provides an overview of different categories of BIPV, presenting the recent developments and sufficient references, and supporting more successful implementations of BIPV for various globe zones. A number of available technologies decide the best selections, and make easy configuration of the BIPV, avoiding any difficulties, and allowing flexibility of design in order to adapt to local environmental conditions, and are adequate to important considerations, such as building codes, building structures and loads, architectural components, replacement and maintenance, energy resources, and all associated expenditure. The passive and active effects of both air-based and water-based BIPV systems have great effects on the cooling and heating loads and thermal comfort and, hence, on the electricity consumption
Micromobility: Progress, benefits, challenges, policy and regulations, energy sources and storage, and its role in achieving sustainable development goals
Micromobility is dominant in urban areas, enhancing the transportation sustainability and assisting in fulfilling the United Nations Sustainable Development Goals (SDGs). This work provides an overall assessment of micromobility: its role under SDGs, policy options, micromobility regulations, emerging technologies, utilisation determinants, energy source, and energy storage. The analysis shows that micromobility could play a major role in achieving the SDGs, specifically SDG 3 (Good Health and Well-being) by lowering toxic gas emissions and reducing projected traffic accidents. Also, the effect on SDG 8 (Decent Work and Economic Growth) by reducing the transportation footprint, on SDG 11 (Sustainable Cities and Communities) by increasing transposition accessibility, reducing traffic congestion and improving the air quality, and equally on SDG 12 (Responsible Consumption and Production) by reducing transportation footprint and increase the sources efficiency. Moreover, micromobility affects SDG 13 (Climate Action) by reducing the greenhouse gases. Furthermore, the analysis shows a clear gap in literature and publications on micromobility, especially in energy management and energy storage area. This review shows that new technology of renewable energy and energy storage could play a significant role in achieving the sustainability of micromobility therefore achieving the SDGs
3D Reconstruction of Fruit Shape based on Vision and Edge Sections
The fruit industry has been known as one of the largest businesses in Malaysia, where most of the fruits pass through the peeling process well in advance before the final product as juice in a bottle or slices in a can. The current industrial fruit peeling techniques are passive and inefficient by cutting parts of the pulp of the fruit with peels leading to losses. To avoid this issue, a multi-axis CNC fruit peeler can be used to precisely peel the outer layer with the guidance of a 3D virtual model of fruit. In this work, a new cost-effective method of 3D image reconstruction was developed to convert 36 fruit images captured by a normal RGB camera to a 3D model by capturing a single image every 10 degrees of fruit rotation along a fixed axis. The point cloud data extracted with edge detection were passed to Blender 3D software for meshing in different approaches. The vertical link frame meshing method developed in this research proved a qualitative similarity between the output result and the scanned fruit in a processing time of less than 50 seconds
The Organizational, Professional and Social Condition Perceived by Novice Teachers
Part of the formation of teacher professional identity is caused by the organizational, professional and social condition perceived by novice teachers. An international collaboration project involving seven countries across African and Asian region was set up under the name of Group C African Asian Dialogue Project in order to survey professional identity among teachers in the respected countries. This article focused on the first dimension of the research collaboration endeavor which is to study the organizational, professional and social condition perceived by novice teachers in Bangladesh, Japan, Malaysia, South Africa, Thailand, Uganda and Vietnam. Novice teachers were chosen as the samples of the study as they are in the crucial position in coping with the transition from being considered as preservice teachers to in-service teachers. The challenges arise when they have to accommodate with what they have learnt in the classroom at the university with the challenges and the realities in the school setting to rationalize the significance of professional identities among the novice teachers. The findings of this study are reported based on the percentage response distribution of each items asked in the questionnaire. The results showed that there are some uniformity and variability on how novice teachers perceive their organizational, professional and social condition in the context of their professional identity.Group C: Teacher Professional Development・Work in this project was funded by a grant funded by Universiti Sains Malaysia, Research University Grant under the account number 1001/PGURU/816280.
・Work in this project was supported by The Network of the “Africa-Asia University Dialogue for Educational Development” (A-A Dialogue)
・This work was supported by the Vietnam National University, Hanoi research fund [grant number QG.16.85]
Metal-Air Batteries—A Review
Metal–air batteries are a promising technology that could be used in several applications, from portable devices to large-scale energy storage applications. This work is a comprehensive review of the recent progress made in metal-air batteries MABs. It covers the theoretical considerations and mechanisms of MABs, electrochemical performance, and the progress made in the development of different structures of MABs. The operational concepts and recent developments in MABs are thoroughly discussed, with a particular focus on innovative materials design and cell structures. The classical research on traditional MABs was chosen and contrasted with metal–air flow systems, demonstrating the merits associated with the latter in terms of achieving higher energy density and efficiency, along with stability. Furthermore, the recent applications of MABs were discussed. Finally, a broad overview of challenges/opportunities and potential directions for commercializing this technology is carefully discussed. The primary focus of this investigation is to present a concise summary and to establish future directions in the development of MABs from traditional static to advanced flow technologies. A systematic analysis of this subject from a material and chemistry standpoint is presented as well
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