Topic Review
Liquid–Liquid Phase Separation
Liquid–liquid phase separation (LLPS) is a thermodynamically-driven, reversible phenomenon consisting in de-mixing into two distinct liquid phases, with different solute concentrations.
  • 9134
  • 29 Aug 2022
Topic Review
Geopolymer Concrete
Geopolymer concrete is a type of concrete that is made by reacting aluminate and silicate bearing materials with a caustic activator, such as fly ash or slag from iron and metal production. It can be a suitable substitute for ordinary Portland cement (OPC). 
  • 8787
  • 18 Feb 2022
Topic Review
Hydrogen Storage and Transportation
In the current hydrocarbon economy, transportation is fueled primarily by petroleum. Burning of hydrocarbon fuels emits carbon dioxide and other pollutants. The supply of economically usable hydrocarbon resources in the world is limited, and the demand of hydrocarbon fuels is increasing, particularly in China, India and other countries. Proponents of a world-scale hydrogen economy argue that hydrogen can be environmentally cleaner source of energy to end-users, particularly in transportation applications, without release of pollutants (such as particulate matter) or carbon dioxide at the point of end use. A recent analysis asserted that “most of the hydrogen supply chain pathways would release significantly less carbon dioxide into the atmosphere than would gasoline used in hybrid electric vehicles” and that significant reductions in carbon dioxide emissions would be possible if carbon capture or carbon sequestration methods were utilized at the site od energy or hydrogen production. Hydrogen storage can be distributed continuously in pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system also pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels. Furthermore, hydrogen is regenerative and environment friendly. But two difficulties with hydrogen are that hydrogen is just an energy carrier and has a low critical temperature of 35 K, i.e., hydrogen is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific surface area (at T< 100K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent and ionic compounds (at ambient pressure), oxidation of reactive metals e.g., Li, Na, Mg, Al, Zn with water. These metals easily react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can be thermally reduced to the metals in a solar furnace. In conclusion, routes for the transmission and storage of hydrogen for chemical processes, and hydrogen-based energy systems are increasing their establishment. Here, these routes are described, considering their attractions and difficulties.
  • 8714
  • 18 Jun 2021
Topic Review
Perceptual Organization
Gestalt theory has provided perceptual science with a conceptual framework relating to brain mechanisms that determine the way we see the visual world. This is referred to as "Perceptual Organization" and has inspired researchers in Psychology, Neuroscience and Computational Design ever since. The major Gestalt principles, such as the principle of Prägnanz, and more importantly the Gestalt laws of perceptual organization, have been critically important to our understanding of visual information processing, how the brain detects order in what we see, and derives likely perceptual representations from statistically significant structural regularities. The perceptual integration of contrast information across co-linear space for the organization of objects in the 2D image plane into figure and ground convey the most elementary basis to our understanding of the visual world. Gestalt theory continues to generate powerful concepts and insights for perceptual science even today, where it is to be placed in the context of image-base decision making by human minds and machines.
  • 8681
  • 22 Mar 2021
Topic Review
Sensors for Health Monitoring
The use of wearable equipment and sensing devices to monitor physical activities, whether for well-being, sports monitoring, or medical rehabilitation, has expanded rapidly due to the evolution of sensing techniques, cheaper integrated circuits, and the development of connectivity technologies. In this scenario, this paper presents a state-of-the-art review of sensors and systems for rehabilitation and health monitoring. Although we know the increasing importance of data processing techniques, our focus was on analyzing the implementation of sensors and biomedical applications. Although many themes overlap, we organized this review based on three groups: Sensors in Healthcare, Home Medical Assistance, and Continuous Health Monitoring; Systems and Sensors in Physical Rehabilitation; and Assistive Systems.
  • 8561
  • 19 Feb 2021
Topic Review
Blockchain Oracle Problem
The Blockchain Oracle Problem refers to the inability of confirming the veracity of the data collected by oracles. Also, depending on the type, the chances of malfunction, and deliberate tampering. 
  • 8548
  • 11 Nov 2020
Topic Review
Modular Multilevel Converters
A modular multilevel converter (MMC) is an advanced voltage source converter applicable to a wide range of medium and high-voltage applications. It has competitive advantages such as quality output performance, high modularity, simple scalability, and low voltage and current rating demand for the power switches. The generalized configuration of a three-phase MMC is comprised of a DC terminal, an AC terminal, and a converting kernel involving three phase legs. Each leg/phase has two symmetric arms referred to as the upper arm and lower arm. The upper arm and lower arm contain a group of identical submodules connected in series together with a chock inductor to suppress high-frequency components in the arm current.  The research interests of MMCs are primarily associated with the topologies, mathematical modeling, output voltage and current control, submodule balancing control, circulating current control, and modulation methods. And the incorporation of wideband gap (WBG) semiconductors are prospected to facilitate the MMC application with further advantages of high-voltage and high-power operations, low power losses, high efficiency, improved reliability, and reduced module size and cooling system.
  • 7521
  • 18 Aug 2021
Topic Review
Participatory Forest Management
Participatory forest management has been considered as a practical and effective strategy for sustainable forest management, especially in situations where land tenure is not securely settled. For effective restoration projects, local communities, as the cornerstone of participatory management, should be provided with incentives to facilitate their participation and active role. We postulate that participation in mangrove restoration projects can not only provide financial rewards but also yield intangible benefits for communities, i.e., social capital upgraded. Our study with the case of coastal mangrove restoration in the Philippines concluded that local people’s participation is a viable option for natural resource management that can create benefits and favorable conditions to communities. 
  • 7469
  • 27 Oct 2020
Topic Review
Palm Wine
The reference to palm wine as a drink with many functionalities has increased over the years. However, few empirical tests have been carried out on humans to substantiate the claims. This perspective looks at the biochemical and microbiological reports on palm wine to highlight the constituents that are associated with functional beverages. Based on the constituents of the drink, it may qualify as a multifunctional beverage because several investigators have demonstrated disease risk reduction, improved nutrition and health outcomes in many studies, albeit in rats rather than humans. The constituents found in functional beverages are present in the drink. However, when assessed under European Union regulations, fermented palm wine (from 3% alcohol) cannot be regarded as a functional beverage because beverages that contain over 1.2% alcohol cannot be approved for any claim on health or nutritional benefit. The fresh sap with much lower alcohol may be suitable after it is refined and subjected to scientific examination to determine quantities of the drink that can confer health benefits on humans.
  • 7301
  • 10 Aug 2021
Topic Review
Ivermectin as Broad-Spectrum Host-Directed Antiviral
The small molecule macrocyclic lactone ivermectin, approved by the US Food and Drug Administration for parasitic infections, has received attention in the last eight years due to its exciting potential as an antiviral. It was identified in a high-throughput chemical screen as inhibiting recognition of the nuclear localizing Human Immunodeficiency Virus 1 (HIV-1) integrase protein by the host heterodimeric importin (IMP) α/β1 complex, and has since been shown to bind directly to IMPα to induce conformational changes that prevent its normal function in mediating nuclear import of key viral and host proteins. Excitingly, cell culture experiments show robust antiviral action towards HIV-1, dengue virus (DENV), Zika virus, West Nile virus, Venezuelan equine encephalitis virus, Chikungunya virus, Pseudorabies virus, adenovirus, and SARS-CoV-2 (COVID-19). Phase III human clinical trials have been completed for DENV, with >60 trials currently in progress worldwide for SARS-CoV-2.
  • 7250
  • 30 Sep 2020
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