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Measurement
Published in James Kidd, Ian Bell, Maths for the Building Trades, 2014
Note: The word mass is used in the SI in preference to weight. Weight describes a pulling force (gravity) the Earth exerts on objects. The strength of this force depends on the object’s position in relation to the centre of the Earth. The nearer it is to the centre of the Earth the greater will be the gravitational force; an object a great distance from the centre of the Earth, e.g. in outer space, will become increasingly less influenced by gravity, and at very great distances it is said to be weightless.
Mineral Processing and Metal Extraction on the Lunar Surface - Challenges and Opportunities
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Matthew Shaw, Matthew Humbert, Geoffrey Brooks, Akbar Rhamdhani, Alan Duffy, Mark Pownceby
One of the most used and overlooked environmental factors in mineral processing and metal production technologies is gravity. The Moon has one sixth of the gravity of Earth at its surface, which has wide implications for most processes used in a mineral processing and metal extraction flowsheet. Whilst some equipment in a generic mineral processing plant, such as slurry pumps, benefit from a lack of gravity due to the reduction of head pressures, the majority of the major processes utilize gravity as a motive force within the equipment or at least as a feed and discharge mechanism. Ball mills for example are unable to operate in microgravity environments, in reduced gravity environments they are theoretically usable but require significant upscaling. A ball mill of 10 m diameter would need to be increased to a diameter of 60 m for an equivalent power draw on the Moon (Craig 2019), this is a size increase of 6 times and represents a large increase in required construction materials. Some equipment such as gravity separators and flotation cells have variants that use centripetal force, replacing gravity with the apparent centrifugal force, these equipment variants may be usable in reduced gravity environments with minor alterations to existing designs.
Performance evaluation of low-cost GPS/INS in-motion alignment model under ECEF frame
Published in International Journal of Image and Data Fusion, 2020
Yunrui Zhang, Qiuzhao Zhang, Chun Ma
As a kind of self-aid and recursive navigation system, INS must realise initial alignment before navigation and appropriate misalignment angle model is the basis of accurate initial alignment. The traditional initial alignment includes static base coarse alignment and fine alignment. The initial alignment method of high precision IMU is different from that of low cost IMU. For high precision IMU, the unknown attitude angle errors converge to small angle errors during coarse alignment. By measuring gravity and earth velocity, compared with standard gravity and earth velocity, the error can be analysed on static base. Under the premise of small attitude error, fine alignment based on inertial navigation error equation can eliminate the residual error, which can be carried out on the stationary base by using gyro compassing theory or with the aid of other sensors Savage (2000).
Real-time collision handling in railway transport network: an agent-based modeling and simulation approach
Published in Transportation Letters, 2019
Poulami Dalapati, Abhijeet Padhy, Bhawana Mishra, Animesh Dutta, Swapan Bhattacharya
where, = speed of train , g = gravity of earth, and = coefficient of kinetic friction. As both the railway tracks and rail wheels are made up of high-quality steel, the values of is taken as = 0.42.