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Topic Review
ShKAS Machine Gun
The ShKAS (Shpitalny-Komaritski Aviatsionny Skorostrelny, Shpitalny-Komaritski rapid fire for aircraft; Russian: ШКАС - Шпитального-Комарицкого Авиационный Скорострельный) is a 7.62 mm calibre machine gun widely used by Soviet aircraft in the 1930s and during World War II. The ShKAS had the highest rate of fire of any aircraft machine gun in general service during WWII. It was designed by Boris Shpitalniy and Irinarkh Komaritsky and entered production in 1934. ShKAS was used in the majority of Soviet fighters and bombers and served as the basis for the ShVAK cannon.
  • 985
  • 24 Nov 2022
Topic Review
Requirements and Types of Face Masks
There are different types of face masks (e.g., 3-ply surgical masks, a wide range of fabric masks, single-use face masks, and face shields) and respirators available commercially to protect individuals from getting and/or spreading COVID-19. Face masks are designed to protect primarily from respiratory droplets and particles to some extent. In contrast, the respirators are designed with extended protection against respiratory droplets, particles, and the virus that cause COVID-19. Both face masks and respirators have certain requirements to ensure performance and efficacy at a reliable and consistent level. Mask standards, ratings. National Institute for Occupational Safety and Health (NIOSH), ASTM International, and International Organization for Standardization (formerly known as International Association for Testing Materials) are engaged in creating an open and transparent consensus standards development process for addressing the standards gap identified during the wake of COVID-19 pandemic. The development of standards aimed to define performance requirements for source control, the protective efficacy of face mask or barrier face coverings, and standardized products to inform user selection decisions. The primary purpose of these specifications is to enable source control to protect the mass public with performance requirements such as protection capability, comfort, reusability, and so on. There are a few basic requirements of face masks to be used effectively, including an excellent fit over the nose and mouth of the user to prevent leaking (use of fitter, base, or nose wire) and the use of multi-layer non-woven but breathable fabrics for preventing bright light.
  • 985
  • 25 Apr 2022
Topic Review
Ramp Metering
Ramp meters are traffic signals installed on freeway ramps to control the frequency at which vehicles enter the flow of traffic.
  • 984
  • 18 Mar 2021
Topic Review
Terrorist and Built Environment
Terrorist impacts have been increasing over time in many countries, being one of the most significant threats for the Built Environment (BE), intended as a network of open spaces (streets, squares) and facing buildings, and their users. Due to the relevance of the perpetrator “will” and the quickness of actions, Terrorism is assimilable to Sudden Onset Disasters (SUOD). BE and its morpho-technological features can be inherently prone or resilient to terrorism risk. The analysis of Risk Mitigation and Reduction Strategies (RMRSs) can support the safety of BE from a sustainable point of view, above all when they transform the existing urban environments.
  • 983
  • 28 Sep 2021
Topic Review
Haptic Devices Designed for Hearing-Impaired People
Haptic devices transmit information to the user, using tactile stimuli to augment or replace sensory input. People with limited sensory abilities, such as vision or hearing can receive supplementary information by relying on them.
  • 982
  • 31 Mar 2023
Topic Review
Combo Washer Dryer
A combo washer dryer (also known more simply as a washer-dryer in the United Kingdom ) is a combination in a single cabinet of a washing machine and a clothes dryer. It should not be confused with a "stackable" combination of a separate washing machine and a separate clothes dryer.
  • 981
  • 08 Nov 2022
Topic Review
Deep Learning in SOC Estimation for Li-Ion Batteries
As one of the critical state parameters of the battery management system, the state of charge (SOC) of lithium batteries can provide an essential reference for battery safety management, charge/discharge control, and the energy management of electric vehicles (EVs). The SOC estimation of a Li-ion battery in the deep learning method uses deep learning theory of computer science to build a model that builds the approximate relationship between input data (voltage, current, temperature, power, capacity, etc.) and output data (SOC) by available data. According to different neural network structures, it can be classified as a single, hybrid, or trans structure. 
  • 981
  • 02 Nov 2022
Topic Review
Copper/Carbon Composites Prepared by Infiltration Technique
The liquid metal infiltration of carbon preformed with copper and its alloys is already an established and well-known process. It is extensively used by the electronic industry to produce heat sinks of power electronics and electric contacts and sliding electric contacts. The advantage of the process is its ability to produce near net shape components with high volume fractions of carbon at a relatively low price. The process is carried out in a vacuum and with low applied pressure. However, a strong dependence on the temperature of infiltration and its precise control is significant for the sound final product. For certain pair carbon matrix–copper alloys, different results could be obtained according to the infiltration temperature. If the temperature is too low, the solidification may occur prior to complete infiltration (high final porosity). When the temperature is too high, undesirable reactions may occur at the fiber–matrix interface (e.g., corrosive carbides). Therefore, there are still a lot of scientific papers pushing this technology to new directions and over old limits. Publications inside scientific journals within this field deal with composite materials for sliding electrical contact and electrical contact materials, sealing materials, parts of brake disks, pantograph strips for high-speed railways, other electric and mechanical applications and even for wall surface shields in future fusion devices.
  • 981
  • 04 Aug 2022
Topic Review
Printed Electrochemical Biosensors
Printing technologies represent powerful tools to combine simpler and more customizable fabrication of electrochemical biosensors with high resolution, miniaturization and integration with more complex microfluidic and electronics systems. Considering this framework, this review provides an overview of the opportunities offered by printed electrochemical biosensors in terms of transducing principles, metrological characteristics and enlargement of the application field, as well as of the main metrological challenges related.
  • 981
  • 14 Dec 2020
Topic Review
Massive MIMO Techniques for 5G
The general concept of massive MIMO is defined as a physical-layer technology which equips each BS with a huge number of active antennas that can be used to spatially multiplex many UEs so that it is possible to communicate with them on the same time-frequency resource. The spectral efficiency per cell can be improved by orders-of magnitude over classical cellular networks by coping with the signal attenuation and interference through spatial signal processing with techniques such as receive combining and transmit precoding. To resume, massive MIMO is an upgraded version of the Space-Division Multiple Access (SDMA), pushing the spatial multiplexing to an extreme level.
  • 981
  • 12 Aug 2021
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