Article
Geochemistry & Geophysics
Rachel S. Kirby, Penelope L. King, Marc D. Norman, Trevor R. Ireland, Margaret Forster, Arthur D. Pelton, Ulrike Troitzsch, Nobumichi Tamura
Summary: By studying the Miles IIE iron meteorite, we found that the silicate inclusions in it were formed in a high-temperature melting event about 4.5 billion years ago, which is consistent with the ages of other similar meteorites. These findings suggest that the formation of silicate inclusions may be due to impact events.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Astronomy & Astrophysics
Alison C. Hunt, Karen J. Theis, Mark Rehkamper, Gretchen K. Benedix, Rasmus Andreasen, Maria Schoenbaechler
Summary: The rapid cooling of iron meteorite parent bodies has been dated using the Pd-107-Ag-107 decay system, showing that the closure times for these meteorites occurred around 7.8-11.7 million years after the formation of calcium-aluminium-rich inclusions. This suggests the persistence of an energetic inner Solar System during this time, possibly due to gas dissipation in the protoplanetary disk and the damping effect of gas drag ceasing. An early giant planet instability between 5 and 14 million years after calcium-aluminium-rich inclusion formation may have reinforced this effect, corresponding well with the timing of impacts recorded by the Pd-Ag system for iron meteorites.
Article
Multidisciplinary Sciences
Marc M. Hirschmann, Edwin A. Bergin, Geoff A. Blake, Fred J. Ciesla, Jie Li
Summary: During the formation of terrestrial planets, volatile loss can occur through various processes such as nebular processing, planetesimal differentiation, and planetary accretion. Iron meteorites are studied as a record of volatile loss during planetesimal processing, revealing that significant open-system silicate melting and volatile loss are crucial in shaping the volatile inventory of terrestrial planets. The composition of parent body cores, characterized by different C/S ratios, suggests that processes affecting composite silicate/iron planetesimals play a key role in shaping volatile compositions.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Astronomy & Astrophysics
Ryo Ogawa, Akiko M. Nakamura, Ayako Suzuki, Sunao Hasegawa
Summary: Research indicates that the depth and diameter of impact craters on the surface of metallic bodies decrease with decreasing temperature and velocity, with a smaller depth/diameter ratio under low temperature and low velocity conditions. Craters formed by metallic projectiles have larger depth/diameter ratios compared to those formed by rock projectiles.
Article
Materials Science, Multidisciplinary
Shuwei Duan, Fuqiang Guo, Shuaishuai Qin, Yu Gao, Kenji Matsuda, Yong Zou
Summary: The microstructure of homogenized Al-Cu-Li alloy is significantly influenced by cooling rates, leading to different phase compositions in air-cooled and furnace cooled samples.
Article
Materials Science, Multidisciplinary
Yuxuan Zhang, Chengpeng Xue, Junsheng Wang, Xinghai Yang, Quan Li, Shuo Wang, Hui Su, Xingxing Li, Yisheng Miao, Ruifeng Dou
Summary: This study quantitatively analyzed the porosity morphology in aluminum-lithium alloys using X-CT. A cellular automaton model was employed to predict the porosity distribution, and it was found that the reduction of hydrogen porosity significantly improved the mechanical properties of the vacuum-cast aluminum-lithium alloy.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Gaoyuan Ouyang, Chad R. Macziewski, Brandt Jensen, Tao Ma, Renu Choudhary, Kevin Dennis, Lin Zhou, Durga Paudyal, Iver Anderson, Matthew J. Kramer, Jun Cui
Summary: This study systematically investigates the effect of cooling rate on physical properties of Fe-6.5wt%Si alloy by changing melt-spin wheel speeds, which significantly affect the solidification temperature profile, ordering, microstructures, textures, hardness, and magnetic properties. The research shows a critical cooling rate at around 1.7 x 10(5) K/s, below which the material embrittlement occurs due to the increase of ordered phases.
Article
Materials Science, Coatings & Films
R. Vignesh, G. Sakthinathan, Raja Velusamy, Seeram Ramakrishna
Summary: The research focused on surface modification of pure magnesium with coatings of pure iron and hydroxyapatite, which improved mechanical strength and decreased corrosion rate. The study showed that all three substrates - pure magnesium, pure iron, and hydroxyapatite - exhibited non-hemolytic properties, and coating did not affect biological characteristics.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Geochemistry & Geophysics
Damanveer S. Grewal, Paul D. Asimow
Summary: In this study, solid-liquid metal partitioning experiments were conducted to estimate the carbon-nitrogen (C/N) ratios of the core of the earliest formed planetesimals using the contents of iron meteorites. The results suggest that the C/N ratios of the core of the parent bodies of iron meteorites are similar to the bulk silicate Earth (BSE), indicating that these planetesimals may have played a role in delivering volatile elements to Earth during its accretion.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Materials Science, Multidisciplinary
Bing Wang, Mingshan Zhang, Junsheng Wang
Summary: This study investigates the formation of microporosity in aluminum alloys with different cooling rates, revealing that high cooling rates increase the nucleation rate of microporosity and adding Cu and Si decreases the solubility of hydrogen during solidification, leading to the formation of microporosity. By controlling the chemistry and applying non-equilibrium solidification conditions, robust casting components can be achieved.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Construction & Building Technology
Zhengyuan Liang, Zhiming Li, Zhengxi Fan
Summary: This study examines the seasonal variation of urban park cooling effect (UPCE) in Nanjing, China. It finds that urban parks have the best cooling effect in summer, with an average temperature reduction of 1.28°C. Factors such as park area, perimeter, and vegetation and water indices play significant roles in the UPCE, and their impacts vary with seasons.
BUILDING AND ENVIRONMENT
(2023)
Article
Metallurgy & Metallurgical Engineering
John Bailey Fletcher, Michael S. Moats
Summary: The performance of grinding media in marked ball wear tests can be affected by galvanic interactions between different media materials. However, the galvanic interaction of media materials has not been thoroughly studied. This research measured the corrosion rates and potentials of high carbon steel and high chromium white iron grinding media using electrochemical testing in simulated mill water. The results showed that high chromium white iron had higher corrosion resistance and potential compared to high carbon steel. The effects of galvanic coupling on corrosion rates were calculated, indicating that high carbon steel can cathodically protect high chromium white iron, resulting in significant decreases in corrosion rate during marked ball wear tests. The degree of protection depended on the pH of the mill water.
MINING METALLURGY & EXPLORATION
(2023)
Article
Crystallography
Vito Speranza, Rita Salomone, Roberto Pantani
Summary: In this study, the influence of pressure on the crystallization kinetics of isotactic polypropylene (iPP) was investigated. It was found that pressure had a significant effect on specific volume changes at high temperatures, but a smaller effect at low temperatures. Increasing pressure resulted in higher crystallization temperatures, while higher cooling rates led to lower temperatures and smaller spherulite sizes.
Article
Multidisciplinary Sciences
Sarah M. Kang, Yue Yu, Clara Deser, Xiyue Zhang, In- Sik Kang, Sun- Seon Lee, Keith B. Rodgers, Paulo Ceppi
Summary: Since the satellite era, Southern Ocean sea surface temperatures (SSTs) have been cooling despite global warming. Recent studies have shown that the impact of Southern Ocean cooling on the tropical Pacific is mediated by subtropical cloud feedbacks, which depend on the model used. In our study, we conduct a coupled model intercomparison and reveal a global impact of observed Southern Ocean cooling, including sea-ice expansion in Antarctica, cooling in the southeastern tropical Pacific, northward shift of the Hadley circulation, weakening of the Aleutian low, and warming in the North Pacific. These findings suggest that the observed Southern Ocean cooling may have contributed to cooler conditions in the eastern tropical Pacific in recent decades.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Geochemistry & Geophysics
Shaunna M. Morrison, Robert M. Hazen
Summary: This article discusses two stages of planetesimal mineralogy that occurred early in the history of the solar nebula, including primary igneous minerals and impact mineralization. These stages mark the first time that high pressures played a significant role in mineral evolution.
AMERICAN MINERALOGIST
(2021)
Article
Astronomy & Astrophysics
S. D. Raducan, T. M. Davison, G. S. Collins
Summary: NASA's DART mission will impact the asteroid Dimorphos at an unknown oblique angle. Simulations using iSALE-3D showed that the efficiency of momentum transfer is similar for different impact angles, but the imparted momentum decreases as the impact angle decreases. The ejected momentum is initially not normal to the surface, but aligns with crater growth. iSALE-2D simulations of vertical impacts provide context for the 3D simulation results and show that the ejection angle varies with target properties and crater growth. These findings can help determine the properties of the target asteroid and guide imaging using the LICIACube.
Article
Geochemistry & Geophysics
V. J. Bray, J. J. Hagerty, G. S. Collins
Summary: This study investigates the formation mechanism and sea depth of the Flynn Creek marine target impact crater through simulations and field observations. The research reveals that the shock pressure and central peak formation are closely related to the sea depth. The study proposes new requirements for drilling marine impact sites and provides a method for accessing mineral indicators that can help determine the formation mechanism of impact craters.
METEORITICS & PLANETARY SCIENCE
(2022)
Article
Multidisciplinary Sciences
Sean E. Wiggins, Brandon C. Johnson, Gareth S. Collins, H. Jay Melosh, Simone Marchi
Summary: NASA's GRAIL spacecraft has discovered that the crust of the Moon is highly porous, and this porosity may be formed by large impacts. This finding has significant implications for understanding subsurface habitable environments on early Earth and Mars.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
G. S. Collins, E. L. Newland, D. Schwarz, M. Coleman, S. McMullan, I. J. Daubar, Katarina Miljkovic, Tanja Neidhart, Eleanor Sansom
Summary: The current rate of small impacts on Mars and the properties of meteoroid fragmentation are constrained by observed impact sites and crater clusters on the martian surface. A calibrated model based on crater cluster observations suggests that the rate of small impacts on Mars is higher than previous estimates and provides insights into impactor properties relevant to seismic wave generation.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Geochemistry & Geophysics
I. J. Daubar, C. M. Dundas, A. S. McEwen, A. Gao, D. Wexler, S. Piqueux, G. S. Collins, K. Miljkovic, T. Neidhart, J. Eschenfelder, G. D. Bart, K. L. Wagstaff, G. Doran, L. Posiolova, M. Malin, G. Speth, D. Susko, A. Werynski
Summary: This study presents a catalog of new impact craters on Mars, with detailed information on their characteristics and the presence of ice. The findings suggest a correlation between the morphological features and environmental factors. The study also highlights interesting factors, such as the color and composition of the blast zones.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Geochemistry & Geophysics
J. Ormo, S. D. Raducan, M. Jutzi, M. Herreros, R. Luther, G. S. Collins, K. Wunnemann, M. Mora-Rueda, C. Hamann
Summary: The impact cratering process on small asteroids is complex and not yet fully understood. Experimental and simulation results suggest that cratering on heterogeneous targets displaces and ejects boulders rather than fragmenting them. The presence of boulders also affects the ejecta angle and distribution around the crater. These findings have implications for understanding the impact processes on asteroids and related missions.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
T. M. Davison, G. S. Collins
Summary: The study shows that compared to existing predictions for oblique impacts, crater diameter is larger; there is little dependence on obliquity for impacts steeper than 45 degrees; crater depth, volume and diameter depend on impact angle in different ways, with shallower craters formed by more oblique impacts.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Colin M. M. Dundas, Michael T. T. Mellon, Liliya V. V. Posiolova, Katarina Miljkovic, Gareth S. S. Collins, Livio L. L. Tornabene, Vidhya Ganesh Rangarajan, Matthew P. P. Golombek, Nicholas H. H. Warner, Ingrid J. J. Daubar, Shane Byrne, Alfred S. S. McEwen, Kimberly D. D. Seelos, Donna Viola, Ali M. M. Bramson, Gunnar Speth
Summary: Water ice in the mid-latitudes of Mars has fluctuated due to the planet's orbit, tilt, and climate changes. A new impact crater near 35 degrees N has revealed the lowest-latitude exposure of subsurface ice on the planet. This crater, the largest of its kind, provides valuable information about the history of Martian climate. The relatively pure ice deposit in the crater was once much thicker and extended beyond 35 degrees N, but it has now mostly vanished and is covered by surface ice.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Matthew J. Genge, Luke Alesbrook, Natasha V. Almeida, Helena C. Bates, Phil A. Bland, Mark R. Boyd, Mark J. Burchell, Gareth S. Collins, Luke T. Cornwell, Luke Daly, Hadrien A. R. Devillepoix, Matthias van Ginneken, Ansgar Greshake, Daniel Hallatt, Christopher Hamann, Lutz Hecht, Laura E. Jenkins, Diane Johnson, Rosie Jones, Ashley J. King, Haithem Mansour, Sarah McMullan, Jennifer T. Mitchell, Gavyn Rollinson, Sara S. Russell, Christian Schroeder, Natasha R. Stephen, Martin D. Suttle, Jon D. Tandy, Patrick Trimby, Eleanor K. Sansom, Vassilia Spathis, Francesca M. Willcocks, Penelope J. Wozniakiewicz
Summary: Fusion crusts form during meteorite atmospheric entry, providing a record of atmospheric deceleration conditions. The Winchcombe meteorite's fusion crust is similar to other stony meteorites, dominated by olivine phenocrysts embedded in a glassy matrix with magnetite and highly vesicular. Unusually abundant dehydration cracks and weak layer failure contribute to particle formation, supported by plasma pulses observed in the fireball videos. Oscillatory zoning in olivine phenocrysts suggests temperature fluctuations from calving events. Unique features include magnetite monolayers and silicate warts, indicating intense gas loss and inter-shower material transfer.
METEORITICS & PLANETARY SCIENCE
(2023)
Article
Geochemistry & Geophysics
T. Neidhart, E. K. Sansom, K. Miljkovic, G. S. Collins, J. Eschenfelder, I. J. Daubar
Summary: We studied 634 clusters of craters on Mars detected from 2007 to 2021, which account for more than half of all impacts found during this period. These clusters are formed when meteoroids in the 10 kg-10 ton mass range break apart in Mars' atmosphere, producing a few to a few hundred fragments that impact the ground. The characteristics of these clusters can provide insights into meteoroid properties and the processes governing their fragmentation. By mapping individual craters within each cluster and analyzing their spatial and size distributions, we defined a range of cluster properties. This large dataset, with over eight times more cluster observations than previous studies, allows for a more comprehensive statistical examination of crater cluster parameters and their correlations. The trends in size, dispersion, and large crater fraction with elevation support the idea of weak atmospheric filtering of materials. The variations in the number of individual craters and their size-frequency distributions within a cluster may reflect differences in fragmentation style, fragility, or internal particle sizes.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Geochemistry & Geophysics
A. Rajsic, K. Miljkovic, N. Wojcicka, G. S. Collins, R. F. Garcia, C. Bredemeyer, A. Lagain, I. J. Daubar, P. Lognonne
Summary: This study combines mapping and numerical simulations to accurately estimate seismic activity and seismic moment generated by small impact events on Mars. By determining the regolith thickness in the late Amazonian units, a more realistic uppermost crust model was constructed. The study found that seismic energy is more dependent on target properties, while seismic moment is almost proportional to impact momentum. The scaling relationships for seismic moment approximations were improved by considering more realistic target properties.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Multidisciplinary Sciences
Sarah C. Steele, Roger R. Fu, Michael W. R. Volk, Thomas L. North, Alec R. Brenner, Adrian R. Muxworthy, Gareth S. Collins, Thomas M. Davison
Summary: The study of the ALH 84001 meteorite suggests that it may preserve a magnetic record of the Martian dynamo from 4.1 billion years ago. By analyzing igneous Fe-sulfides in the meteorite using a quantum diamond microscope, it was found that there are strongly magnetized ferromagnetic mineral assemblages in two nearly opposite directions. This implies that the meteorite recorded strong fields after impact heating between 4.1 and 3.95 billion years ago and was later heterogeneously remagnetized by at least one further impact.
Article
Astronomy & Astrophysics
Robert Luther, Sabina D. Raducan, Christoph Burger, Kai Wuennemann, Martin Jutzi, Christoph M. Schaefer, Detlef Koschny, Thomas M. Davison, Gareth S. Collins, Yun Zhang, Patrick Michel
Summary: This study uses three different shock physics codes to simulate momentum transfer from impactor to target and investigates the agreement between the results. By aligning the crushing behavior, the consistency between the models is improved and scaling parameters for ejecta curtain studies are derived.
PLANETARY SCIENCE JOURNAL
(2022)