Experimental Impacts into Feldspar Phenocrysts

Meteorite impact craters are the dominant surface feature on most terrestrial planetary bodies [1]. The extreme temperatures and pressures generated by hypervelocity impact events produce a variety of microscopic shock metamorphic effects in minerals, as well as non-exclusive shock-related features such as pervasive fracturing and brecciation.<p></p> Studies of shock effects in feldspar group minerals have been limited due to the the comparatively rapid rate at which feldspars weather, and the complexity of their microtextures which renders them difficult to study using conventional optical techniques. However, feldspars are becoming increasingly investigated for use as shock barometers due to their importance in planetary studies and meteoritics, where rocks often contain little or no quartz [e.g., 2]. This provides the motivation to examine more closely the effects of high-velocity impact of a projectile, in the method of [3], into a feldspathic target, in order to the resultant microstructural variation.<p></p&gt

Survival of fossils under extreme shocks induced by hypervelocity impacts

Experimental data are shown for survival of fossilized diatoms undergoing shocks in the GPa range. The results were obtained from hypervelocity impact experiments which fired fossilized diatoms frozen in ice into water targets. After the shots, the material recovered from the target water was inspected for diatom fossils. Nine shots were carried out, at speeds from 0.388 to 5.34?km?s?1, corresponding to mean peak pressures of 0.2–19?GPa. In all cases, fragmented fossilized diatoms were recovered, but both the mean and the maximum fragment size decreased with increasing impact speed and hence peak pressure. Examples of intact diatoms were found after the impacts, even in some of the higher speed shots, but their frequency and size decreased significantly at the higher speeds. This is the first demonstration that fossils can survive and be transferred from projectile to target in hypervelocity impacts, implying that it is possible that, as suggested by other authors, terrestrial rocks ejected from the Earth by giant impacts from space, and which then strike the Moon, may successfully transfer terrestrial fossils to the Moon

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

AbstractDuring hypervelocity impact (>a few kms−1) the resulting cratering and/or disruption of the target body often outweighs interest on the outcome of the projectile material, with the majority of projectiles assumed to be vaporised. However, on Earth, fragments, often metallic, have been recovered from impact sites, meaning that metallic projectile fragments may survive a hypervelocity impact and still exist within the wall, floor and/or ejecta of the impact crater post-impact. The discovery of the remnant impactor composition within the craters of asteroids, planets and comets could provide further information regarding the impact history of a body. Accordingly, we study in the laboratory the survivability of 1 and 2mm diameter copper projectiles fired onto ice at speeds between 1.00 and 7.05kms−1. The projectile was recovered intact at speeds up to 1.50kms−1, with no ductile deformation, but some surface pitting was observed. At 2.39kms−1, the projectile showed increasing ductile deformation and broke into two parts. Above velocities of 2.60kms−1 increasing numbers of projectile fragments were identified post impact, with the mean size of the fragments decreasing with increasing impact velocity. The decrease in size also corresponds with an increase in the number of projectile fragments recovered, as with increasing shock pressure the projectile material is more intensely disrupted, producing smaller and more numerous fragments. The damage to the projectile is divided into four classes with increasing speed and shock pressure: (1) minimal damage, (2) ductile deformation, start of break up, (3) increasing fragmentation, and (4) complete fragmentation. The implications of such behaviour is considered for specific examples of impacts of metallic impactors onto Solar System bodies, including LCROSS impacting the Moon, iron meteorites onto Mars and NASA’s “Deep Impact” mission where a spacecraft impacted a comet

Exploring the Influential Determinants of IoT Adoption in the U.S. Manufacturing Sector

Manufacturers have been hesitant to adopt the Internet of Things (IoT) due to a lack of understanding of factors related to IoT adoption. This correlational study uses a combination of diffusion of innovation theory and technology–organization–environment framework to examine if a relationship exists between relative advantage, complexity, compatibility, technology readiness, top management support, firm size, competitive pressure, and regulatory support and intent to adopt IoT in U.S. manufacturing organizations. A sample of 168 IT leaders was used. Multiple regression analysis indicated significant relationships between intent to adopt IoT and three variables: technology readiness, top management support, and competitive pressure. The model was able to predict approximately 44% of the variation of IT leaders’ intent to adopt IoT. The results can help IT leaders in the U.S. manufacturing sectors understand the factors that influence IoT adoption