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Topic Review
AEM for Alkali Metal–Air Batteries
Rechargeable alkali metal-air batteries have enormous potential in energy storage applications due to their high energy densities, low-cost and environment friendliness. Membrane separators determine the performance and economic viability of these batteries. Usually, porous membrane separators taken from lithium-based batteries are used. Moreover, composite and cation-exchange membranes have been tested. However, crossover of unwanted species (such as zincate ions in zinc-air flow batteries) and/or low hydroxide ions conductivity are major issues to be overcome. On the other hand, state-of-art Anion-Exchange Membranes (AEMs) have been applied to meet the current challenges with regard to rechargeable zinc-air batteries, which has received the most attention among alkali metal-air batteries. The recent advances and remaining challenges of AEMs for these batteries are critically discussed. Correlation between the properties of the AEMs and performance and cyclability of the batteries has been established.
  • 2.0K
  • 27 Oct 2020
Topic Review
Radio Broadcasting
Radio broadcasting is transmission by radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both. Alternatives to terrestrial radio broadcasting include cable radio, local wire television networks, satellite radio, and internet radio via streaming media on the Internet. The signal types can be either analog audio or digital audio.
  • 2.0K
  • 30 Nov 2022
Topic Review Peer Reviewed
Structural Systems for Tall Buildings
Structural systems for tall buildings have gone through an evolutionary process. The rigid frame became popular in the first half of the 20th century but proved to be structurally inefficient beyond a certain height of tall buildings. The invention of the tubular structure in the 1960s allowed buildings to be built taller with low material consumption. Due to the obstructive nature of the closely spaced exterior columns of framed tubes and bracings of braced tubes, the core-outrigger system gained acceptance by the architects as it allowed them to freely articulate the façade design. However, the conventional tubular structures continued to retain their use for tall buildings to a lesser degree and later underwent a resurgence in modified forms. These and other advanced tubular forms in cutting-edge structural systems developed later continue to find application in modern times. This study presents a detailed narrative of different structural systems for tall buildings that is expected to assist structural engineers and architects to collaboratively select appropriate structural systems for tall buildings. 
  • 2.0K
  • 08 Jul 2022
Topic Review
Digital Twins for Additive Manufacturing
A brief state-of-the-art  introduction of digital twins for additive manufacturing.
  • 2.0K
  • 17 Feb 2021
Topic Review
Semaphore Telegraph
A semaphore telegraph is an early system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position. The most widely used system was invented in 1792 in France by Claude Chappe, and was popular in the late eighteenth to early nineteenth centuries. Lines of relay towers with a semaphore rig at the top were built within line-of-sight of each other, at separations of 5–20 miles (8.0–32.2 km). Operators at each tower would watch the neighboring tower through a spyglass, and when the semaphore arms began to move spelling out a message, they would pass the message on to the next tower. This system was much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. Semaphore lines were a precursor of the electrical telegraph, which would replace them half a century later, and would also be cheaper, faster, and more private. The line-of-sight distance between relay stations was limited by geography and weather, and prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station. Modern derivatives of the semaphore system include flag semaphore (a flag relay system) and the heliograph (optical telegraphy using mirror-directed sunlight reflections).
  • 2.0K
  • 28 Nov 2022
Topic Review
Poly(Ethylene Terephthalate) Microplastics
The high PET production volume and the waste mismanagement of PET litter make it one of the most polluting plastic material. Its diffusion in marine litter is widely assessed according to public opinion and documented in the literature. The major sources of PET microplastics in the marine environment are bottles and fibers. The role of PET micro/nanoplastics of vector of toxic chemicals, their fate and the negative effects on the environment and human health is still under discussion.
  • 2.0K
  • 27 Apr 2021
Topic Review
Biomass Pyrolysis
Pyrolysis process has been considered to be an efficient approach for valorization of lignocellulosic biomass into bio-oil and value-added chemicals. Bio-oil refers to biomass pyrolysis liquid, which contains alkanes, aromatic compounds, phenol derivatives, and small amounts of ketone, ester, ether, amine, and alcohol. Lignocellulosic biomass is a renewable and sustainable energy resource for carbon that is readily available in the environment. This review article provides an outline of the pyrolysis process including pretreatment of biomass, pyrolysis mechanism, and process products upgrading. The pretreatment processes for biomass are reviewed including physical and chemical processes. In addition, the gaps in research and recommendations for improving the pretreatment processes are highlighted. Furthermore, the effect of feedstock characterization, operating parameters, and types of biomass on the performance of the pyrolysis process are explained. Recent progress in the identification of the mechanism of the pyrolysis process is addressed with some recommendations for future work. In addition, the article critically provides insight into process upgrading via several approaches specifically using catalytic upgrading. In spite of the current catalytic achievements of catalytic pyrolysis for providing high-quality bio-oil, the production yield has simultaneously dropped. This article explains the current drawbacks of catalytic approaches while suggesting alternative methodologies that could possibly improve the deoxygenation of bio-oil while maintaining high production yield.
  • 2.0K
  • 21 Jul 2020
Topic Review
Working Principle of Hydraulic Control System
Hydraulic control systems are a feedback control system that uses hydraulic components as control and execution components, and hydraulic oil as the working medium for energy transmission. The movement of hydraulic actuators refers to the system output (including displacement, velocity, acceleration, and force), which is transmitted to the controller through feedback components. The input signal of the control component is adjusted according to the error size, so that the system output can automatically, quickly, and accurately track the system input instructions. Hydraulic control systems are classified into pump-controlled hydraulic control systems and valve-controlled hydraulic control systems based on their various control modes and valve components.
  • 2.0K
  • 18 Dec 2023
Topic Review
Devices Using Qualcomm Snapdragon Systems-on-Chip
This is a list of devices using Qualcomm Snapdragon chips. Snapdragon is a family of mobile system on a chip (SoC) made by Qualcomm for use in smartphones, tablets, and smartbook devices.
  • 2.0K
  • 07 Nov 2022
Topic Review
Joining Laminated Electrical Steels
In recent years, the motor has been increasingly used to replace the conventional gasoline engine for carbon emission reduction, and the high-performance motor is urgently required. The stator and rotor in a motor are made of hundreds of joined and laminated electrical steels. This paper covers the current research in joining the laminated electrical steels for the motor application, together with the critical assessment of our understanding. It includes the representative joining method, modeling of the joining process, microstructure of the weld zone, mechanical strength and magnetic properties. The gaps in the scientific understanding, and the research needs for the expansion of joining laminated electrical steels, are provided.
  • 2.0K
  • 11 Nov 2020
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