Topic Review
Shaft Mining
Shaft mining or shaft sinking is excavating a vertical or near-vertical tunnel from the top down, where there is initially no access to the bottom. Shallow shafts, typically sunk for civil engineering projects differ greatly in execution method from deep shafts, typically sunk for mining projects. When the top of the excavation is the ground surface, it is referred to as a shaft; when the top of the excavation is underground, it is called a winze or a sub-shaft. Small shafts may be excavated upwards from within an existing mine as long as there is access at the bottom, in which case they are called Raises. A shaft may be either vertical or inclined (between 45 and 90 degrees to the horizontal), although most modern mine shafts are vertical. If access exists at the bottom of the proposed shaft and ground conditions allow then raise boring may be used to excavate the shaft from the bottom up, such shafts are called borehole shafts. Shaft sinking is one of the most difficult of all development methods: restricted space, gravity, groundwater and specialized procedures make the task quite formidable. Historically mine shaft sinking has been among the most dangerous of all the mining occupations and the preserve of mining contractors called sinkers. Today shaft sinking contractors are concentrated in Canada , Germany and South Africa .
  • 14.1K
  • 17 Nov 2022
Topic Review
MP3 Player
An MP3 player is an electronic device that can play MP3 digital audio files. It is a type of digital audio player (DAP), or portable media player. Most players play more than the MP3 file format, such as Windows Media Audio (WMA), Advanced Audio Coding (AAC), Vorbis, FLAC, Speex and Ogg.
  • 14.1K
  • 19 Oct 2022
Topic Review
Photovoltaic Cell Generations
Solar energy is one of the most demanding renewable sources of electricity. Electricity production using photovoltaic technology not only helps meet the growing demand for energy, but also contributes to mitigating global climate change by reducing dependence on fossil fuels. The level of competitiveness of innovative next-generation solar cells is increasing due to the efforts of researchers and scientists related to the development of new materials, particularly nanomaterials and nanotechnology.
  • 13.9K
  • 25 Aug 2022
Topic Review
BMW 5 Series (E39)
The BMW E39 is the fourth generation of BMW 5 Series, which was sold from 1995 to 2004. It was launched in the sedan body style, with the wagon/estate body style (marketed as "Touring") introduced in 1996. The E39 was replaced by the E60 5 Series in 2003, however E39 Touring models remained in production until May 2004. The proportion of chassis components using aluminium significantly increased for the E39, and it was the first 5 Series to use aluminium for all major components in the front suspension or any in the rear. It was also the first 5 Series where a four-cylinder diesel engine was available. Rack and pinion steering was used for the first time in a 5 Series (with the exception of the E34 525iX), being fitted to the four-cylinder and six-cylinder models. Unlike its E34 predecessor and E60 successor, the E39 was not available with all-wheel drive. The high performance M5 sedan was introduced in 1998, powered by the 4.9-litre S62 V8 engine. It was the first M5 model to be powered by a V8 engine.
  • 13.1K
  • 05 Dec 2022
Topic Review
CCR Model (DEA)
The first Data Envelopment Analysis (DEA) model developed by Charnes, Cooper and Rhodes (1978) under the assumption of a Constant Returns to Scale production technology, i.e.,  when an increase in the production resources results in a proportional increase in the output.
  • 12.3K
  • 30 May 2021
Topic Review
Energy Management Strategy
A Comprehensive Review on Classification, Energy Management Strategy, and Control Algorithm for Hybrid Electric Vehicles
  • 12.0K
  • 22 Oct 2020
Topic Review
Yield
In chemistry, yield, also referred to as reaction yield, is a measure of the quantity of moles of a product formed in relation to the reactant consumed, obtained in a chemical reaction, usually expressed as a percentage. Yield is one of the primary factors that scientists must consider in organic and inorganic chemical synthesis processes. In chemical reaction engineering, "yield", "conversion" and "selectivity" are terms used to describe ratios of how much of a reactant was consumed (conversion), how much desired product was formed (yield) in relation to the undesired product (selectivity), represented as X, Y, and S.
  • 11.6K
  • 18 Oct 2022
Topic Review
In-Vehicle Networks
Modern vehicles are no longer simply mechanical devices. Connectivity between the vehicular network and the outside world has widened the security holes that hackers can use to exploit a vehicular network. Controller Area Network (CAN), FlexRay, and automotive Ethernet are popular protocols for in-vehicle networks (IVNs) and will stay in the industry for many more years. However, these protocols were not designed with security in mind. They have several vulnerabilities, such as lack of message authentication, lack of message encryption, and an ID-based arbitration mechanism for contention resolution. Adversaries can use these vulnerabilities to launch sophisticated attacks that may lead to loss of life and damage to property. Thus, the security of the vehicles should be handled carefully. In this paper, we investigate the security vulnerabilities with in-vehicle network protocols such as CAN, automotive Ethernet, and FlexRay. A comprehensive survey on security attacks launched against in-vehicle networks is presented along with countermeasures adopted by various researchers. Various algorithms have been proposed in the past for intrusion detection in IVNs. However, those approaches have several limitations that need special attention from the research community. Blockchain is a good approach to solving the existing security issues in IVNs, and we suggest a way to improve IVN security based on a hybrid blockchain.
  • 11.4K
  • 15 Apr 2021
Topic Review
Process of Converting Ammonia to Hydrogen
Hydrogen technology for transition to a hydrogen-based economy requires supplying clean and renewable energy and capture of CO2 from current fossil hydrogen production. Ammonia is the most popular substance as a green hydrogen carrier because it does not carry carbon, and the total hydrogen content of ammonia is higher than other fuels and is thus suitable to convert to hydrogen. Ammonia cracking is a process of producing hydrogen from ammonia decomposition over a catalyst at high temperatures and is preferentially performed at normal pressures. 
  • 11.3K
  • 12 Dec 2022
Topic Review
Applications of Fibre Reinforced Polymer
Three FRP shapes are used in Structural Engineering applications: FRP profiles for new construction, FRP rebars and FRP strengthening systems. Applications in bridges, buildings, railway platforms, cooling towers and repair and rehabilitation of existing structures are presented. FRP is a strong and lightweight sustainable material with lower carbon footprint than traditional materials. However, FRPs are not as widely used as expected. FRP use in repair and rehabilitation has seen significant growth, though, over last two decades. The major challenges have been steel-like FRP elements, lack of ductility, almost no legal design guidelines and inadequate knowledge about fire and durability performance. The future of FRPs can be promising if engineers use this material more for net-zero carbon construction, and to effectively deal with climate emergency.
  • 11.0K
  • 28 Mar 2022
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