Habitat Bennu: Design Concepts for Spinning Habitats Constructed From Rubble Pile Near-Earth Asteroids

The authors explore the possibility that near-earth, rubble pile asteroids might be used as habitats for human settlement by increasing their rotation to produce spin gravity. Using previously published scaling by Maindl et al. and studies of asteroid populations, it is shown that there is no class of hollowed body that would survive the spin-up process on its own without additional reinforcement. Large solid-rock asteroids (diameter D > 10 km) would not have the tensile strength to withstand the required rotation rates and would fracture and break apart. Smaller asteroids, being ‘rubble piles’, have little tensile strength and would quickly disperse. The possibility of containing the asteroid mass using higher-strength materials like carbon nanofiber is instead considered. It is found that a moderate tensile strength container can maintain the integrity of a large spinning cylinder composed of dispersed asteroid regolith. The research extends the range of possible asteroid habitat candidates, since it may become feasible to construct habitats from the more numerous smaller bodies, including NEAs (Near Earth Asteroids). The required tensile strength of the container material scales with habitat radius and thickness and is ∼ 200 MPa for a starting asteroid body of radius 300 m that is spun up to provide 0.3 g⊕ while increasing its radius to 3 km and maintaining a rubble and regolith shield thickness of 2 m to protect against cosmic rays. Ambient solar power can be harvested to aid in spin-up and material processing.

Planetary Cities: Fluid Rock Foundations of Civilization

Whereas recent framings of planetary urbanization stress the planet-scaled impacts of contemporary urban processes, we might also conceive of cities as being constitutively ‘planetary’ from their very outset. This article looks at two ways in which the earliest urban centres or ‘civilizations’ on the floodplains of the Fertile Crescent harnessed the deep, geological forces of the Earth. The first is the tapping and channelling of sedimentary processes, central to what Wittfogel referred to as hydraulic civilizations (1963). The second is the use of high-heat technologies to smelt and forge metals, which can be construed as a capture of igneous processes. What both sets of practices have in common is that they involve skilled intervention in fluid-solid phase transitions between solid rock and flowing particulate matter. Viewing cities as constitutively geological or planetary in this way can help us reimagine the challenges posed to urban spaces by looming transformations in Earth systems.

Landslide Zone Investigation by Determining Cracks and Cracks Compressive Strength Test in Waru District, Pamekasan Regency

Landslide zone investigation has been conducted using geoelectricity to determine the number of cracks and using a compressive strength test to determine compressive strength cracks. The result of this research is that the rock layers of Waru District consist of soil layers resulting from the weathering of quartz rock into quartz sandstone. This quartz sandstone lies on top of a more solid rock layer. The type of landslide that is formed in the Waru sub-district is translational. This type of landslide is caused by water entering the lower layer, causing landslides and the number of cracks that trigger landslides. The results of the low compressive strength test resulted in landslides. This result was due to a decrease in the number of pores filled with water and an increase in the pores that were not filled with water. This occurs due to the presence of water in the cracks, the number of cracks cavities, and the density of the cracks which results in reduced adhesion between the cracks holding layers.

Felsic melt migration via porous flow – a numerical modeling approach

<p>Melting of the continental crust and subsequent melt transport has been most thoroughly described in the case of metasedimentary rocks. In these rocks segregation and migration of melt occur either through an interconnected network of veins and melt-rich layers (leucosome) or in form of diapirs. For these rocks, porous flow of melt at grain scale is mostly regarded only as a transient stage of separation of melt from the solid rock.</p><p>An entirely different style of melting and melt transport occurs in the case of felsic metaigneous rocks. We use the example from the Bohemian Massif, the eastern European Variscan belt, where metaigneous migmatites were studied in large detail. Here, melt did not segregate from the solid rock but migrated pervasively along most of the grain boundaries and equilibrated with the host rock. This equilibration resulted in formation of a continuous sequence of texturally, geochemically and compositionally different migmatites.</p><p>The question arises, what are the conditions and driving forces for this unusual behavior. We attempt to address this question by means of numerical modeling of two-phase flow (i.e. flow of porous solid matrix and melt), using the open-source finite-element ASPECT code (aspect.geodynamics.org). Most previous numerical studies of this process were either purely generic or focused on the melting of the mantle. In order to study this process in crustal conditions, we set up a 2D crustal-scale thermo-mechanical model that includes melting and freezing. We investigate the role of material properties (viscosity, solidus and liquidus temperatures, solid matrix permeability, melt composition) and thermal and velocity boundary conditions, as well as the effect of grid resolution. The results are discussed in terms of realistic parameter values and possible styles of melt migration and deformation of the matrix.</p>

To build upon solid rock or to build upon sand:

Starting with a rereading of the information literacy theories, we characterized the development of this concept, distinguish it and relate it with associated terms. After this theoretical framing, we focused on the role of the information literacy in the school context. We present our study based in the analyses of information behaviour, reading habits and information practices of students in Vila do Conde municipal area, using the school library collections and technological resources, considering also the location, access and use of information. We do a brief general view over this group of school libraries in this municipal area, but we focused our analysis of the research universe in three schools of 1st level, one E.B. 2,3 and another secondary school, using an inquiry by a questionnaire. To better contextualise our study we also make the characterization and framing of each school library in its surroundings (city, rural and piscatorial) in order to allow a comparative analysis of the results.

Labin ili izvedba undergrounda kao jedan od modusa otpora izolaciji/periferiji

Using the example of the town of Labin in Istria, I demonstrate how isolation, the so-called periphery, can also serve as an expression of resistance in a cultural niche. The collective Labin Art Express (L.A.E., initiated by Dean Zahtila, late Krešimir Farkaš, Graziano Kršić) is the initiator of the fundamental L.A.E. project Underground City XXI ‒ independent underground Labin cultural city as an alternative to the existing above-ground, heteronomous Labin, i.e. the creation of a real city 150 m below the earth’s surface ‒ in underground halls and tunnels, carved in solid rock, connecting Labin, Raša, Plomin and Rabac, with streets, bars, galleries, swimming pools, playgrounds for children, shops, restaurants, the Museum of Mining and Industry of Istria. Thereby we can compare Labin in terms of urbanity and anthropology with the town of Katowice, which in 2018 was selected to host the most significant UN Climate Change Conference, following the 2015 Paris Agreement. Katowice were chosen as one of Europe’s most polluted sites due to the exploitation of coal i.e. the transition of the aforementioned town from a mining and industrial site to a modern industrial, economical, technological and cultural centre.

Forced Fold Amplitude and Sill Thickness Constrained by Wireline and 3-D Seismic Data Suggest an Elastic Magma-Induced Deformation in Tarim Basin, NW China

Disparities between fold amplitude (A) and intrusion thickness (Hsill) are critical in identifying elastic or inelastic deformation in a forced fold. However, accurate measurement of these two parameters is challenging because of the limit in separability and detectability for the seismic data. In the TZ-47 exploring area from the Tarim Basin, Northwest China, we combined wireline data and 3-D seismic data, to accurately constrain the fold amplitude and total thickness of sills that inducing the roof uplift. The measurement results show that the forced fold amplitude is 155 m and the total sill thickness is 148.4 m. When using a magma density of 2.7 g/cm3, and solid rock density of 3 g/cm3, the molten magma thickness at the time of intrusion would be 153.8 m, which is almost no difference from the forced fold amplitude. Therefore, the TZ-47 fold is a pure elastic forced fold induced by emplacement of multiple sills. Measurement solely based on seismic data may not be able to detect some thin interlayers and may result in large errors.

Possible ways of optimizing blasting operations using O-Pitblast software

Blasting is one method of mining solid rock masses. The operation parameters, i.e. burden, blast hole and row spacing, stemming length, subdrilling length or explosive charge mass per single delay and total explosive charge mass per series, must be determined. The determined parameters can be optimized taking into account both technical and economic performance, using a dedicated software with an optimization module. The article presents different ways of improving and optimizing blasting operation parameters using O-Pitblast software and the effects of these improvements on planned blasting operations.