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Topic Review Video
Direct Carbon Fuel Cells
Most fuel cells invariably use gaseous or liquid fuels. A fuel cell technology that has attracted attention only recently, the direct carbon fuel cell (DCFC) uses solid fuel (carbon) and converts the chemical energy in the carbon to electricity through its direct participation in the fuel cell reactions and electrochemical oxidation. The fuel use can be almost 100% compared with about 85% for most other fuel cells. The electrical efficiency is expected to be above 70% - almost twice those of current generation coal-fired plants leading to 50% reduction in greenhouse gas emissions. The amount of CO2 for storage/sequestration is also halved. Moreover, the exit gas is almost pure carbon dioxide stream, requiring no or minimal gas separation and processing for sequestration. Therefore, the energy and cost penalties to capture the CO2 will be significantly less than for other technologies. However, the technology is at an early stage of development requiring many complex challenges to be overcome, related to materials and corrosion, fuel delivery mechanism, and system development, before it can be commercialized. Section 19.4 of a recent book by the author gives an overview of this technology focusing on its main issues (Sequeira, 2019.). Two of the main DCFCs, the direct carbon molten carbonate fuel cell (DC-MCFC) and the direct carbon solid oxide fuel cell (DC-SOFC) are described in this topic review. 
  • 2.8K
  • 04 Aug 2021
Topic Review
Early Chinese Cartography
Early Chinese cartography began in the 5th century BC during the Warring States period when cartographers started to make maps of the Earth's surface. Its scope extended beyond China's borders with the expansion of the Chinese Empire under the Han dynasty. It entered its golden age with the invention of the compass in the 11th century during the Song dynasty, and reached its peak in the 15th century when the Ming dynasty admiral Zheng He went on a series of voyages to the South China Sea, Indian Ocean, and beyond.
  • 2.8K
  • 10 Oct 2022
Topic Review
Camel Milk Processing
The camel milk market was limited for a long time by its almost exclusive self-consumption use in nomadic camps. Significant development has been observed for the past two or three decades, including internationally, boosted by its reputation regarding its health effects for regular consumers.  The main change lies in the diversification of the camel dairy products offered to the consumers.
  • 2.8K
  • 06 May 2021
Topic Review
Enlightenment in Buddhism
The English term enlightenment is the western translation of the abstract noun bodhi, (/ˈboʊdi/; Sanskrit: बोधि; Pali: bodhi), the knowledge or wisdom, or awakened intellect, of a Buddha. The verbal root budh- means "to awaken," and its literal meaning is closer to "awakening." Although the term buddhi is also used in other Indian philosophies and traditions, its most common usage is in the context of Buddhism. The term "enlightenment" was popularised in the Western world through the 19th century translations of Max Müller. It has the western connotation of general insight into transcendental truth or reality. The term is also being used to translate several other Buddhist terms and concepts, which are used to denote (initial) insight (prajna (Sanskrit), wu (Chinese), kensho and satori(Japanese)); knowledge (vidhya); the "blowing out" (Nirvana) of disturbing emotions and desires and the subsequent freedom or release (vimukti); and the attainment of supreme Buddhahood (samyak sam bodhi), as exemplified by Gautama Buddha. What exactly constituted the Buddha's awakening is unknown. It may probably have involved the knowledge that liberation was attained by the combination of mindfulness and dhyāna, applied to the understanding of the arising and ceasing of craving. The relation between dhyana and insight is a core problem in the study of Buddhism, and is one of the fundamentals of Buddhist practice. In the western world the concept of (spiritual) enlightenment has taken on a romantic meaning. It has become synonymous with self-realization and the true self and false self, being regarded as a substantial essence being covered over by social conditioning., , ,
  • 2.8K
  • 28 Oct 2022
Topic Review
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are analogous, whereas homologous structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evolution, which occurs when two independent species evolve in the same direction and thus independently acquire similar characteristics; for instance, gliding frogs have evolved in parallel from multiple types of tree frog. Many instances of convergent evolution are known in plants, including the repeated development of C4 photosynthesis, seed dispersal by fleshy fruits adapted to be eaten by animals, and carnivory.
  • 2.8K
  • 24 Oct 2022
Topic Review
Insulin Effects on Target Tissues
Glucose levels in blood must be constantly maintained within a tight physiological range to sustain anabolism. Insulin regulates glucose homeostasis via its effects on glucose production from the liver and kidneys and glucose disposal in peripheral tissues (mainly skeletal muscle). Blood levels of glucose are regulated simultaneously by insulin-mediated rates of glucose production from the liver (and kidneys) and removal from muscle; adipose tissue is a key partner in this scenario, providing nonesterified fatty acids (NEFA) as an alternative fuel for skeletal muscle and liver when blood glucose levels are depleted. During sleep at night, the gradual development of insulin resistance, due to growth hormone and cortisol surges, ensures that blood glucose levels will be maintained within normal levels by: (a) switching from glucose to NEFA oxidation in muscle; (b) modulating glucose production from the liver/kidneys. After meals, several mechanisms (sequence/composition of meals, gastric emptying/intestinal glucose absorption, gastrointestinal hormones, hyperglycemia mass action effects, insulin/glucagon secretion/action, de novo lipogenesis and glucose disposal) operate in concert for optimal regulation of postprandial glucose fluctuations. The contribution of the liver in postprandial glucose homeostasis is critical. The liver is preferentially used to dispose over 50% of the ingested glucose and restrict the acute increases of glucose and insulin in the bloodstream after meals, thus protecting the circulation and tissues from the adverse effects of marked hyperglycemia and hyperinsulinemia.
  • 2.8K
  • 03 Mar 2021
Topic Review
Energy-Saving and Sustainable Building Systems
Generally, energy used in a building can be accrued in various ways and a statistical process can be used for studying the building’s overall performance and minimizing the energy requirement of the building. Different statistical models are used to interpret the real-world data in terms of individual theory to develop energy-efficient buildings. Underfloor air distribution, double-glazed windows, use of highly efficient electric motors and variable speed drives may play a great role in reducing building energy consumption. In the UK, the application of double-glazed windows in commercial buildings can save 39–53% energy. The proper maintenance of a building’s central heating system can save up to 11% energy. The automatic HVAC control system can reduce up to 20% of the building’s total heating load. Proper utilization of a VSD system in motor and building performance optimization by an ANOVA tool also proved instrumental in saving energy.
  • 2.8K
  • 10 Feb 2022
Topic Review
Shipbuilding Supply Chain 4.0
The supply chain is currently taking on a very important role in organizations seekingto improve the competitiveness and profitability of the company. Its transversal character mainly places it in an unbeatable position to achieve this role. This article, through a study of each of the key enabling technologies of Industry 4.0, aims to obtain a general overview of the current state of the art in shipbuilding adapted to these technologies. To do so, a systematic review of what the scientific community says is carried out, dividing each of the technologies into di erent categories. In addition, the global vision of countries interested in each of the enabling technologies is also studied. Both studies present a general vision to the companies of the concerns of the scientific community, thus encouraging research on the subject that is focused on the sustainability of theshipbuilding supply chain.
  • 2.8K
  • 14 Apr 2021
Topic Review
Physical Activity Patterns
Although “physical activity pattern” (PAP) is a widely used expression, its precise meaning remains vague. Indeed, PAP is sometimes used to describe physical activity (PA) levels/intensities, however the term is also applied to express how PA averages differ among group,  between different days (i.e., week and weekend days), across seasons (e.g., summer, winter), and between school and vacation time. A lack of a formal definition for PAP has not prevented researchers from using a vast array of instruments to measure PA (accelerometers, pedometers, questionnaires, direct observations, and heart rate monitors) in an attempt to capture PAP. Discrepancies also exist in how PAP has been expressed with researchers using daily mean PA, heart rate frequency, number of daily steps, time engaged in certain types of activity, and/or engagement in sports activities. Researchers have also used numerous statistical procedures in their attempts to capture PAP. Notwithstanding this diversity, we suggest that PAP should be used to jointly capture similarities/dissimilarities as well as stabilities/changes in children’s PA at an intra-personal level. PAP should be used to best describe individual streams of behaviours, and not exclusively PA levels/intensities. A formal and clear definition of PAP would support important, systematic, and coherent lines of empirical enquiry.
  • 2.8K
  • 24 Apr 2021
Topic Review
Metal Matrix Composites
Metal matrix composites (MMCs) present extraordinary characteristics, including high wear resistance, excellent operational properties at elevated temperature, and better chemical inertness as compared to traditional alloys. These properties make them prospective candidates in the fields of aerospace, automotive, heavy goods vehicles, electrical, and biomedical industries. MMCs are challenging to process via traditional manufacturing techniques, requiring high cost and energy. The laser-melting deposition (LMD) has recently been used to manufacture MMCs via rapid prototyping, thus, solving these drawbacks. Besides the benefits mentioned above, the issues such as lower ultimate tensile strength, yield strength, weak bonding between matrix and reinforcements, and cracking are still prevalent in parts produced by LMD. In this article, a detailed analysis is made on the MMCs manufactured via LMD. An illustration is presented on the LMD working principle, its classification, and dependent and independent process parameters. Moreover, a brief comparison between the wire and powder-based LMDs has been summarized. Ex- and in-situ MMCs and their preparation techniques are discussed. Besides this, various matrices available for MMCs manufacturing, properties of MMCs after printing, possible complications and future research directions are reviewed and summarized.
  • 2.8K
  • 18 May 2021
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