Abstract. Recent research work has been undertaken to investigate the feasibility of forming micro-components by combining Electrical-field activated sintering and microforming (Micro-FAST). This paper firstly introduces the Micro-Fast technology and experimental validation method employed. Cylindrical components were used for the experiments and the sintering and forming was realised by use of a Gleeble 3800 thermalmechanical simulator. Thirteen different types of powders (metallic and ceramic) with variable particle sizes have been formed successfully. The influential parameters, such as pressure, temperature and heating rate, were studied. From the experiment results it is shown that the component quality depends significantly on the pressure, the heating rate and maximum temperature applied. Compared to other sintering technologies, the relatively short forming-cycle time of Micro-Fast (increased heating rate and reduced holding time) makes a good contribution to highly efficient particulate sintering for micro-manufacturing.
Lightning strikes happens in a fraction of time, where they can transfer huge amounts of charge and high currents in a single strike. The chances for a structure to be struck by lightning increases as the height increases; thus, tall structures are more prone to lightning. Despite the existing lightning protection systems available for wind turbine blades, there are still many cases reported due to the fact of damage caused by lightning strike. Owing to that, the present work introduces a new approach for a lightning protection system for wind turbine blades where preliminary investigations were done using Analysis Systems (ANSYS) Workbench. Two models were developed: one with a conventional type down conductor system and the other with a hybrid conductor system. The recorded findings have been compared and discussed, where it was found that the hybrid conductor system may provide alternative protection from lightning for wind turbine blades.
Abstract.A NiTi shape memory alloy, known as nitinol, has been intensively studied for last five decades. The NiTi alloy with large size is commonly produced by vacuum sintering, thermal explosion mode of self-propagating high-temperature synthesis (TE-SHS) and spark plasma sintering (SPS). These methods are, however, rarely utilized for the forming of miniature and micro-sized components and have their own limits and disadvantages, such as long process chains and low efficiency with the processes. In the study reported in this paper, an innovation in rapid powder consolidation technology, called Micro-FAST (combining micro-forming and electric-current activated sintering techniques (FAST)) is introduced for the forming of micro-components in which the loose powders are loaded directly into the die, followed by electric-sintering. In the study, 4.0 mm × 4.0 mm miniature cylinders were formed with pre-alloyed NiTi powders. Sintered sample with relative density of 98.65% has been fabricated at a sintering temperature of 1150°C in a relatively short cycle time (119.5 s). Based on the results of SEM and XRD, it was found that the densified samples with Ni 3 Ti, NiTi and NiTi 2 phases were produced.
Abstract. As demands on miniature products increase significantly, a rapid process and production system for high-throughput, highly flexible and cost-efficient volume production of miniaturised components made from a wide range of materials is needed. A novel and electrical-field-activated sintering and forming process shows the potential to produce solid parts from powder material without any binder. Using titanium (Ti) and titanium alloy (90Ti10Sn) powder material, several processing parameters have been investigated, such as pressure, heating rate, heating temperature and holding time, which helped to contribute to the optimum result. In this study, using graphite dies, graphite punches and tungsten carbide punches, solid samples were produced, having a cylinder shape of Ø4.00 mm × 4.00 mm. Several properties of the solid Ti and 90Ti10Sn samples, such as density, hardness and the microstructures, were examined, and these showed that good results have been obtained.
Bangladesh, being a developing country, needs an uninterrupted electricity supply to sustain and expand economic growth. The government’s strategic vision of 2021 and the international commitment under the Paris Agreement has meant to attract new capital investments for renewable electricity generation by diversifying energy blends, ranging from natural gas to more reliable coal technologies and renewable energy. To understand the practical implementation of such policies, this paper explores the key factors of the renewable energy (RE) sector of Bangladesh. This research has adopted the strengths, weaknesses, opportunities, and threats (SWOT) analysis method to examine the RE market and to understand the determinants of foreign direct investment (FDI) to attract new investments. For the analysis purposes, data were collected from extant literature and semi-structured interviews from the RE experts in Bangladesh. This study bears significance as it empirically reflects the government’s vision and strategy on RE development and analyzes its challenges and recommends accordingly. The analysis of the study reveals that the regulatory framework, tax haven/exemption, higher tariff, and presence of government guarantee are the major strengths to draw foreign investment. On the contrary, land acquisition, lack of coordination and collaboration among government authorities, administrative procedures, corruption, and access to local finance turns out to be the key weaknesses to consider while investing in this sector. In terms of the external factors, increasing energy demand, increasing global awareness of climate change, and decreasing cost of RE setup equipment act as potent opportunities; while the dominance of fossil fuel and discontinuity of energy policies should be taken as threats that can hinder the flow of investment in this sector. Hence, in order to attract sustainable FDI in the RE sector, several key areas need to be strengthened in the short, medium, and long-term. These are: (i) regulations on non-discriminatory treatment to foreign investors; (ii) control of corruption; (iii) protection of intellectual property rights; and (iv) coordination and collaboration between ministries.
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