Toward the utilisation of resources in space: knowledge gaps, open questions, and priorities

There are many open science questions in space resource utilisation due to the novelty and relative immaturity of the field. While many potential technologies have been proposed to produce usable resources in space, high confidence, large-scale design is limited by gaps in the knowledge of the local environmental conditions, geology, mineralogy, and regolith characteristics, as well as specific science questions intrinsic to each process. Further, the engineering constraints (e.g. energy, throughput, efficiency etc.) must be incorporated into the design. This work aims to summarise briefly recent activities in the field of space resource utilisation, as well as to identify key knowledge gaps, and to present open science questions. Finally, future exploration priorities to enable the use of space resources are highlighted

The beneficiation of lunar regolith for space resource utilisation: A review

Space Resource Utilisation (SRU) technology will enable further exploration and habitation of space by humankind. The production of oxygen on the Moon is one of the first objectives for SRU; this can be achieved through the thermo-chemical reduction of the lunar regolith. Several techniques, such as hydrogen reduction and molten salt electrolysis, have been proposed. All reduction techniques require a consistent feedstock from the regolith to reliably and consistently produce oxygen. The preparation of this feedstock, known as beneficiation, is a critical intermediate stage of the SRU flowsheet, however it has received little consideration relative to the preceding excavation, and the subsequent oxygen production stage. This review describes the physics of the main beneficiation methods suitable for SRU. Further, we collate and review all of the previous studies on the beneficiation of lunar regolith

United they stand

Community-managed programme implemen­tation is a new concept in the development arena of Bangladesh. Unlike other development agencies, NGO Forum for Drinking Water Supply & Sanitation follows the community-focussed and community-managed approach instead of target group approach. In the Community­managed WatSan Programme approach of NGO Forum a Village Development Committee (VDC), formed with the participation of the respective village people, works in the focal point for ensuring the successful implementation and sustainability of WatSan services

Small mammal diversity in Semi-deciduous Seasonal Forest of the southernmost Brazilian Pampa: the importance of owl pellets for rapid inventories in human-changing ecosystems

The Pampa biogeographic province covers a mere 2% of the Brazilian territory (176,496 km2). However, it stands out as a complex and diverse ecosystem, although its mammal communities are still scarcely understood. Human activities are transforming the territory into a mosaic of agroecosystems, native and exotic forest fragments, and grasslands. Here we conducted the first investigation to determine the richness of small mammal assemblages in the region based on extensive analyses of owl pellets (Tyto furcata). Craniodental remains were studied from samples collected from 12 Semi-deciduous Seasonal Forest sites in the municipality of São Lourenço do Sul, State of Rio Grande do Sul, Southern Brazil. A total of 2,617 individuals belonging to 19  taxa were recorded, including 2 marsupials (Didelphidae; 0.42%), 2 chiropterans (Molossidae, Phyllostomidae; 0.12%), and 15 rodents (Cricetidae, Muridae, Caviidae; 99.46%). The rodent genera Oligoryzomys, Mus, Calomys, and Akodon were the most common taxa. Large samples also included poorly known taxa, such as the cricetids Bibimys, Juliomys (recording here its southernmost occurrence), Lundomys, and Wilfredomys. From a biogeographical point of view, the recorded assemblage embraces a mixture of Platan, Pampean, and Atlantic Forest elements, highlighting the role of the southernmost Brazilian hills as a wedge favoring the penetration of forest micromammals to higher latitudes. Our findings testify to the great diversity of the Pampa, but also point to a growing homogeneity and dominance of rodent species that are widespread in agroecosystems. Rapid inventories based on owl pellets emerge as a suitable, economic, non-invasive tool to document these community changes.Fil: Stutz, Narla Shannay. Universidade Federal do Rio Grande do Sul; BrasilFil: Hadler, Patrícia. Universidade Federal de Santa Catarina; BrasilFil: Cherem, Jorge José. Cooperativa para a Conservação da Natureza (Caipora); BrasilFil: Pardiñas, Ulises Francisco J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentina. Instituto Nacional de Biodiversidad; Ecuado

Pliocene sigmodontine rodents (Mammalia: Cricetidae) in northernmost South America: test of biogeographic hypotheses and revised evolutionary scenarios

We document the first occurrence of Sigmodontinae (Mammalia, Rodentia, Cricetidae) from the Pliocene of northern South America, from the San Gregorio Formation of northwestern Venezuela. The recovered isolated molars are identified as Oligoryzomys sp. and Zygodontomys sp., two currently widespread sigmodontines in South America. These records constitute the oldest representatives of these genera, potentially new species, and the first Pliocene occurrence for Oryzomyini and the whole subfamily outside Argentina. Hypotheses on the historical biogeography of sigmodontines have been constructed almost exclusively using genetic data and the fossils we report provide a new kind of evidence. The occurrence of Oligoryzomys sp. and Zygodontomys sp. in Venezuela provides novel information for the diversification models suggested for Oligoryzomys, by supporting a potential eastern corridor of open environments from northern to southern South America. The presence of sigmodontines from the locality home of the new reports, Norte Casa Chiguaje, is consistent with the palaeoenvironmental conditions originally proposed for it based on mammals and botanical records, being characterized as mixed open grassland/forest areas surrounding permanent freshwater systems. The new sigmodontine evidence is used to discuss the putative scenarios of the ancient evolution of the subfamily in South America, favouring a model in which open areas (savannahs) to the east of the Andes played crucial role aiding or obstructing Late Miocene-Pliocene sigmodontine dispersion southwards

A universal framework for Space Resource Utilisation (SRU)

Space Resource Utilisation (SRU) or In Situ Resource Utilisation (ISRU) is the use of natural resources from the Moon, Mars and other bodies for use in situ or elsewhere in the Solar System. The implementation of SRU technologies will provide the breakthrough for humankind to explore further into space. A range of extraction processes to produce usable resources have been proposed, such as oxygen production from lunar regolith, extraction of lunar ice and construction of habitation by 3D printing. Practical and successful implementation of SRU requires that all the stages of the process flowsheet (excavation, beneficiation and extraction) are considered. This requires a complete ‘mine-to-market’ type approach, analogous to that of terrestrial mineral extraction. One of the key challenges is the unique cross-disciplinary nature of SRU; it integrates space systems, robotics, materials handling and beneficiation, and chemical process engineering. This is underpinned by knowledge of the lunar or planetary geology, including mineralogy, physical characteristics, and the variability in local materials. Combining such diverse fields in a coordinated way requires the use of a universal framework. The framework will enable integration of operations and comparison of technologies, and will define a global terminology to be used across all fields. In this paper, a universal SRU flowsheet and terminology are described, and a matrix approach to describing regolith characteristics specifically for SRU is proposed. This is the first time that such an approach has been taken to unify this rapidly-developing sector

Characterisation of solid hydrodynamics in a three-phase stirred tank reactor with positron emission particle tracking (PEPT)

It is challenging to measure the hydrodynamics of stirred tank reactors when they contain multiphase flows comprising liquid, gas bubbles and particles. Radioactive particle tracking techniques such as positron emission particle tracking (PEPT) are the only established techniques to determine internal flow behaviour due to the inherent opacity and density of fluid and the vessel walls. The profiles of solids flow are an important tool for robust reactor design and optimisation and offer insight into underlying transport processes and particle–fluid–bubble interactions for applications such as froth flotation. In this work, measurements with PEPT were performed with two tracer particles differing in surface hydrophobicity to characterise the solids hydrodynamics in a baffled vessel agitated with a Rushton turbine. The location data from PEPT were averaged with time to estimate the probability density function (PDF) of particle velocity in individual voxels. The peaks of these voxel distributions were used to produce profiles of solids flow in different azimuthal and horizontal slices. Bimodal vertical velocity distributions were observed in the impeller radial jet which suggest the particles experienced trajectory crossing effects due to inertia. Statistical tests were performed to compare the velocity distributions of the hydrophilic and hydrophobic tracer particles, which indicated similar average flow behaviour in the liquid or pulp phase of the vessel and differences near the air inlet, in the impeller discharge stream and pulp–froth interface. With tracers designed to represent gangue and valuable mineral species, the differences in velocity reveal interactions such as bubble–particle attachment and entrainment

Comperative analysis of the DI diesel engine in-cylinder fluid flow applying PIV measurements and CFD simulations

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.To improve the efficiency of diesel engines several actions have been performed. Beside the reduction of internal friction by applying new and more effective materials, the thermodynamics offer different opportunities to influence the engine performance and emissions. Especially the interaction of fuel and air flow within the combustion chamber should be investigated. Therefore an optimized in-cylinder flow can enhance air-fuel mixing and lead to lower exhaust emissions and less fuel consumption. In addition the turbulent flow within the cylinder exhibits large- and small-scale cyclic variations[1]. The turbulence characteristics and cycle to cycle fluctuations of the in-cylinder flow can also have a pronounced influence on the combustion process and evoke the need to be thoroughly investigated. Nowadays CFD simulations are widely used to predict and optimise the air flow within internal combustion engines, but such numerical calculations require a comparison with experimental data. Particle Image Velocimetry (PIV) was applied on an optically accessible single cylinder diesel engine to receive data sets for validation purpose. This engine provides access through a glass ring with 30 mm height and a modified piston bowl with an integrated glass bottom. In order to detect the local dependencies of the air flow, the velocity fields were quantified in two horizontal and three vertical measurement planes. A high resolution double shutter camera and a high energy double pulse laser were applied to measure the velocity fields during the intake and compression phases. In order to study the cyclic fluctuations, instantaneous snapshot pairs from 100 successive cycles were taken. As a result of the strong turbulences inside the internal combustion chamber strong cyclic fluctuations were observed at all investigated measurement planes. The measured averaged in-cylinder velocities and indicated pressures were compared with a k-ε turbulence model simulation, based on an Unsteady Reynolds Averaged NavierStockes (URANS) approach. In addition, the swirl and tumble characteristics were calculated and checked against the measured ones. Despite a sufficient accordance between the experimentally determined and k-ε model calculated in-cylinder velocities, discrepancies in swirl and the tumble flow could be observed. Therefore the air flow was also simulated using a Scale-Adaptive Simulation (SAS) turbulence model in order to resolve the small scale turbulences inside the combustion chamber. The achieved solution was compared with the velocities fields, averaged over 100 cycles, as well as the single cycle velocities to avoid the elimination of small scale turbulences due to cyclic variations.cf201