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Development of mineral supply and demand from 1950 to 2020
Published in Natalia Yakovleva, Edmund Nickless, Routledge Handbook of the Extractive Industries and Sustainable Development, 2022
Mark Burnett, Steven E. Zhang, Yousef Ghorbani, Julie E. Bourdeau, Benedikt M. Steiner, James S.K. Barnet, Glen T. Nwaila
Airborne geophysical surveys, especially by helicopter, are becoming increasingly common in the exploration of ore deposits. Three-dimensional seismic surveys became possible through developments in digital recording and computing, facilitating realistic depictions of reservoirs and deposits to aid exploration, resource modelling, and mine planning. A major technological shift in mining was experienced, with hydraulic equipment replacing conventional equipment due to greater operational efficiencies. During the same period, Komatsu developed and trialled unmanned haulage trucks. Metallurgical processing technology also received a technological boost, with the solvent extraction – electrowinning (SX/EW) process for copper being tested, allowing for even lower-grade deposits to be exploited (Anderson et al., 2014).
Air quality and factors related to sub-optimal pig housing conditions in nursery and finishing rooms
Published in Thomas Banhazi, Andres Aland, Jörg Hartung, Air Quality and Livestock Farming, 2018
Christelle Fablet, Fabrice Bidan, Virginie Dorenlor, Florent Eono, Eric Eveno, Nicolas Rose, François Madec
Seven factors influencing air quality in nursery and finishing rooms were related to building design and engineering. Large rooms and a small air volume per pig are two parameters associated with sub-optimal air quality in both nursery and finishing rooms. In a similar vein, the pen surface area was related to air quality in finishing rooms. In our study, pen surface area was positively correlated with the number of pigs per pen (data not shown) which was itself correlated with room size. The effect of the number of pigs on airborne particulate levels has already been shown in the literature. Indeed, Gustafsson (1999) found a linear relationship between the number of pigs and the dust generated. In another study, the dust concentration increased along with the number of pigs per room (Massabie et al., 2006). The number of animals in the same airspace thus influences the level of airborne particles. The risk of transmitting suspended particles is reported to rise exponentially in keeping with the increasing number of pigs sharing airspace (Sorensen et al., 2006). However, to the best of our knowledge, the effect of air volume per pig on air quality is described here for the first time. Airborne pollutants, mainly produced by the pigs themselves, are much more likely to be concentrated in a small volume of air than a higher one, where air compounds may be diluted.
Airborne and Spaceborne Laser Profilers and Scanners
Published in Jie Shan, Charles K. Toth, Topographic Laser Ranging and Scanning, 2017
Gordon Petrie, Charles K. Toth
The original SHOALS system had a laser pulse repetition rate of 200 Hz—hence the designation SHOALS-200. It was flown using a Bell helicopter as the airborne platform. In 1998, the system was modified, including the fitting of a new laser that doubled the pulse rate to 400 Hz—hence the name SHOALS-400. The system was mounted in a Twin Otter aircraft. The positioning of the SHOALS system was carried out using a dual-frequency GPS receiver carrying out differential measurements, either in conjunction with local base stations or using the Fugro OmniSTAR system, in combination with an IMU that provided the required attitude measurements. The horizontal accuracies that were achieved were quoted as being ±1 to 3 m, while the vertical accuracy was stated to be ±15 cm. The scan pattern was defined by the lasers being pointed forward at an angle of 20° to the vertical, with the scan mechanism producing an arc of coverage in front of the aircraft. The laser range measurements were supplemented by a video camera that continuously recorded video frame imagery of the area being covered.
Reducing COVID-19 airborne transmission risks on public transportation buses: an empirical study on aerosol dispersion and control
Published in Aerosol Science and Technology, 2021
Nathan J. Edwards, Rebecca Widrick, Justin Wilmes, Ben Breisch, Mike Gerschefske, Jon Sullivan, Richard Potember, Angelica Espinoza-Calvio
With 84 overall experiments (34 characterization tests and 50 statistical runs), this study demonstrates not only the complexity of the turbulent air environment in a moving bus, but also clearly shows that air exchange, air flow, filtration, and masks have a significant effect on aerosol dispersion control. One important conclusion is that the wearing of a mask by an infected person in the shared airspace will directly affect the factors of P, D, T and R and significantly reduce overall airborne dispersion in a bus. Wearing of masks reduced the overall particle count released into the bus by an average of 50% or more depending on mask quality and reduced the dispersion distance by several feet. When masks were not worn, dispersed particles spread rapidly throughout the whole bus. Another important conclusion from the results is that maintaining airflow, fully or partially, reduces aerosol particle counts and the associated risks.
A study of capacity regulations to define European air traffic management network states
Published in Transportation Planning and Technology, 2021
Rasoul Sanaei, Alexander Lau, Volker Gollnick
The air transportation system consists of four elements (airlines, airports, airspace and aircraft) each representing a specific industry with a set of stakeholders (Hirst 2008). Such a mixture of numerous interacting actors in the air transportation system allows defining various types of networks. The definition of network is a key step especially when we intend to investigate a system property, i.e. resilience, in a complex network based system. If passenger transfer is in focus, it is well established to define airports as nodes of the network and flight connections as respective links. Likewise a focus on route optimization is more consistent to a network describing an airline route network. In the case of airspace configuration, a network with unweighted directional links and NAVAIDs (visual or electronic devices, airborne or on the earth’s surface, that provide point-to-point guidance information or position data to aircraft in flight (www.eurocontrol.int/atmlexicon)), waypoints and airports representing nodes will be suggested.
Sensitivity analysis of parameters and contrasting performance of ground filtering algorithms with UAV photogrammetry-based and LiDAR point clouds
Published in International Journal of Digital Earth, 2020
Petr Klápště, Michal Fogl, Vojtěch Barták, Kateřina Gdulová, Rudolf Urban, Vítězslav Moudrý
Point clouds derived from light detection and ranging (LiDAR) and airborne photogrammetry have become commonplace data sources for digital terrain models (DTMs) production. DTMs are generated through point cloud filtering (i.e. the process of identification of points representing bare ground and dividing the point cloud into the ground and non-ground parts) followed by interpolation. Both airborne laser scanning (ALS; i.e. LiDAR sensor is mounted on-board an aircraft or helicopter) and UAV photogrammetry-derived DTMs have been equally used in many disciplines such as forestry (Balenović et al. 2018; Tomaštík et al. 2017), hydrology (Rahman et al. 2017), restoration ecology (Koska et al. 2017; Szostak et al. 2019), or precision agriculture (Kumhálová and Moudrý 2014; Méndez-Vázquez et al. 2019).