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Topic Review
Indian Regional Navigation Satellite System
The Indian Regional Navigation Satellite System (IRNSS), with an operational name of NAVIC (acronym for NAVigation with Indian Constellation; also, nāvik 'sailor' or 'navigator' in Sanskrit, Hindi, and many other Indian languages), is an autonomous regional satellite navigation system that provides accurate real-time positioning and timing services. It covers India and a region extending 1,500 km (930 mi) around it, with plans for further extension. An extended service area lies between the primary service area and a rectangle area enclosed by the 30th parallel south to the 50th parallel north and the 30th meridian east to the 130th meridian east, 1,500–6,000 km (930–3,730 mi) beyond borders. The system currently consists of a constellation of seven satellites, with two additional satellites on ground as stand-by. The constellation is in orbit as of 2018, and the system was expected to be operational from early 2018 after a system check. NAVIC will provide two levels of service, the "standard positioning service", which will be open for civilian use, and a "restricted service" (an encrypted one) for authorised users (including the military). NAVIC is planned to become available for civilian use in the first half of 2020. There are plans to expand the NAVIC system by increasing its constellation size from 7 to 11.
  • 1.9K
  • 12 Oct 2022
Topic Review
Dugout Canoe
A dugout canoe or simply dugout is a boat made from a hollowed tree. Other names for this type of boat are logboat and monoxylon. Monoxylon (μονόξυλον) (pl: monoxyla) is Greek -- mono- (single) + ξύλον xylon (tree) -- and is mostly used in classic Greek texts. In German, they are called Einbaum ("one tree" in English). Some, but not all, pirogues are also constructed in this manner. Dugouts are the oldest boat type archaeologists have found, dating back about 8,000 years to the Neolithic Stone Age. This is probably because they are made of massive pieces of wood, which tend to preserve better than, e.g., bark canoes. Along with bark canoe and hide kayak, dugout boats were also used by indigenous peoples of the Americas.
  • 1.9K
  • 25 Oct 2022
Topic Review
Power Estimation for Electric Vehicles’s Lithium-Ion Batteries
State of power (SOP), as one of the key states of lithium-ion batteries, is defined as the peak power capability that a battery could deliver or receive over a prediction window while keeping the battery within the safe operating area. By this definition, most existing methods for online SOP estimation employ an equivalent-circuit model (ECM) to simulate battery dynamic behaviour in a prediction window and assume batteries operating at three operation modes, namely the constant current (CC), constant voltage (CV), and constant current constant voltage (CCCV) modes. Accordingly, three online SOP estimation methods have been developed with different basic principles, and many efforts have been made in the past decades for the improved performance of online SOP estimation from three aspects: (1) model structure; (2) online parameter identification technique; and (3) SOP estimation algorithm. 
  • 1.9K
  • 05 Jan 2022
Topic Review
Batavia (Ship)
Batavia (Dutch pronunciation: [baːˈtaːviaː] (listen)) was a ship of the Dutch East India Company (VOC). It was built in Amsterdam, Dutch Republic, in 1628, and armed with 24 cast-iron cannons and a number of bronze guns. Batavia was shipwrecked on her maiden voyage, and was made famous by the subsequent mutiny and massacre that took place among the survivors. A twentieth-century replica of the ship is also called the Batavia and can be visited in Lelystad, Netherlands.
  • 1.9K
  • 15 Nov 2022
Topic Review
CO2 Storage in Shale Reservoirs
As a new “sink” of CO2 permanent storage, the depleted shale reservoir is very promising compared to the deep saline aquifer. To provide a greater understanding of the benefits of CO2 storage in a shale reservoir, a comparative study is conducted by establishing the full-mechanism model, including the hydrodynamic trapping, adsorption trapping, residual trapping, solubility trapping as well as the mineral trapping corresponding to the typical shale and deep saline aquifer parameters from the Ordos basin in China. The results show that CO2 storage in the depleted shale reservoir has merits in storage safety by trapping more CO2 in stable immobile phase due to adsorption and having gentler and ephemeral pressure perturbation responding to CO2 injection. The effect of various CO2 injection schemes, namely the high-speed continuous injection, low-speed continuous injection, huff-n-puff injection and water alternative injection, on the phase transformation of CO2 in a shale reservoir and CO2-injection-induced perturbations in formation pressure are also examined. With the aim of increasing the fraction of immobile CO2 while maintaining a safe pressure-perturbation, it is shown that an intermittent injection procedure with multiple slugs of huff-n-puff injection can be employed and within the allowable range of pressure increase, and the CO2 injection rate can be maximized to increase the CO2 storage capacity and security in shale reservoir.
  • 1.9K
  • 11 Jan 2021
Topic Review
Smart Grids（SG）
Smart grid (SG), an evolving concept in the modern power infrastructure, enables the two-way flow of electricity and data between the peers within the electricity system networks (ESN) and its clusters. The self-healing capabilities of SG allow the peers to become active partakers in ESN. In general, the SG is intended to replace the fossil fuel-rich conventional grid with the distributed energy resources (DER) and pools numerous existing and emerging know-hows like information and digital communications technologies together to manage countless operations.
  • 1.9K
  • 01 Jul 2021
Topic Review
Non-Mechanical Hybrid Hydrogen Compression
Non-mechanical hybrid hydrogen compressors consists of a first electrochemical compression stage followed by a second one based on the adsorption-desorption of hydrogen on microporous materials. They allow compressing hydrogen up to 70 MPa. Non-mechanical hybrid hydrogen compressors can be a valid alternative to the mechanical compressors. 
  • 1.9K
  • 29 Jun 2020
Topic Review
Titanium Aluminides
Titanium aluminides (TiAl) have the potential of substituting nickel-based superalloys (NBSAs) in the aerospace industries owing to their lightweight, good mechanical and oxidation properties. Functional simplicity, control of sintering parameters, exceptional sintering speeds, high reproducibility, consistency and safety are the main benefits of spark plasma sintering (SPS) over conventional methods. Though TiAl exhibit excellent high temperature properties, SPS has been employed to improve on the poor ductility at room temperature. Powder metallurgical processing techniques used to promote the formation of refined, homogeneous and contaminant-free structures, favouring improvements in ductility and other properties are discussed. This article further reviews published work on phase constituents, microstructures, alloy developments and mechanical properties of TiAl alloys produced by SPS. Finally, an overview of challenges in as far as the implementation of TiAl in industries of interest are highlighted.
  • 1.9K
  • 07 Jan 2021
Topic Review
Removal of Inorganic Nitrogen from Wastewater
Water contamination due to various nitrogenous pollutants generated from wastewater treatment plants is a crucial and ubiquitous environmental problem nowadays. Nitrogen contaminated water has manifold detrimental effects on human health as well as aquatic life. Consequently, various biological and bioelectrochemical treatment processes are employed to transform the undesirable forms of nitrogen in wastewater to safer ones for subsequent discharge.
  • 1.9K
  • 27 May 2022
Topic Review
Hybrid Convolutional Neural Network–Bidirectional Long Short-Term Memory
Recognition of lying is a more complex cognitive process than truth-telling because of the presence of involuntary cognitive cues that are useful to lie recognition. Researchers have proposed different approaches in the literature to solve the problem of lie recognition from either handcrafted and/or automatic lie features during court trials and police interrogations.
  • 1.9K
  • 09 Apr 2024
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