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
Geochemistry & Geophysics
Zhongtian Zhang, David Bercovici, Linda Elkins-Tanton
Summary: Many asteroids may have been shattered by collisions and reaccumulated into porous rubble piles, with a negative correlation between size and porosity for stony asteroids, and suspected metallic asteroids showing larger porosities. Our models suggest that compaction between boulders occurs through cataclastic fracturing for silicate/chondritic boulders, while cold welding and deformation play a role in metal boulders.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Astronomy & Astrophysics
Wladimir Neumann, Matthias Grott, Mario Trieloff, Ralf Jaumann, Jens Biele, Maximilian Hamm, Ekkehard Kuehrt
Summary: Observations of C-type near-Earth asteroids and laboratory investigations of carbonaceous chondritic meteorites indicate a high microporosity of C-type asteroids. The study calculates the evolution of temperature and porosity to constrain parameters that result in microporosities compatible with Ryugu's high-porosity material and likely burial depths for observed boulders at the surface, suggesting distinct evolution paths for Ryugu's parent body compared to carbonaceous chondrites.
Review
Astronomy & Astrophysics
Peter M. Miklavcic, John Siu, Esteban Wright, Alex Debrecht, Hesam Askari, Alice C. Quillen, Adam Frank
Summary: In this paper, the authors explore the potential of using near-earth asteroids as habitats for human settlement. They find that it is possible to maintain the integrity of a rotating asteroid by using high-strength materials as containers. This research expands the range of possible asteroid habitats and suggests the feasibility of constructing habitats from smaller bodies.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2022)
Article
Geochemistry & Geophysics
M. Yasui, M. Arakawa, H. Okawa, S. Hasegawa
Summary: In this study, cratering experiments were performed on simulated rubble-pile asteroid surfaces. The researchers improved the previously studied crater size scaling relationship by considering the armoring effect and introduced the concept of momentum transfer efficiency. The experiments showed that the size ratio of the target bead to the projectile, as well as the impact velocity, affected the size scaling relationship.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Astronomy & Astrophysics
Naoya Tanabe, Yuichiro Cho, Eri Tatsumi, Tatsuki Ebihara, Koki Yumoto, Tatsuhiro Michikami, Hideaki Miyamoto, Tomokatsu Morota, Chikatoshi Honda, Patrick Michel, Katharina Otto, Olivier Barnouin, Kazuo Yoshioka, Hirotaka Sawada, Yasuhiro Yokota, Naoya Sakatani, Masahiro Hayakawa, Rie Honda, Shingo Kameda, Moe Matsuoka, Manabu Yamada, Toru Kouyama, Hidehiko Suzuki, Kazunori Ogawa, Seiji Sugita
Summary: Recent asteroid missions have discovered that sub-kilometer asteroids are often composed of rubble piles covered with boulders larger than tens of centimeters. A new method has been developed to automatically measure the abundance and size distribution of small boulders through analyzing the surface radiance variation during the spinning of the asteroid. The method was applied to images of Ryugu and Itokawa, revealing global distributions of boulders and their size variations on these asteroids.
PLANETARY AND SPACE SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
Arshad Ali, Iffat Jabeen, Sobhi J. Nasir, Nak Kyu Kim, Hwayoung Kim
Summary: The new L-type ordinary chondrites have distinct characteristics in terms of fayalite and ferrosillite contents in olivine and low-Ca pyroxene, respectively. There is a correlation between Fe/Mg and Fe/Mn ratios in olivine, as well as comparability in oxygen isotope compositions between the newly analyzed L-type meteorites and various clasts of NWA 869. It is suggested that larger asteroids formed and evolved as an onion-shell structure, undergoing internal heating, metal-silicate segregation, and thermal metamorphism, followed by fragmentation and gravitational collapse.
JOURNAL OF AFRICAN EARTH SCIENCES
(2023)
Review
Materials Science, Paper & Wood
Arijit Dutta Gupta, Nikhil Kirti, Parul Katiyar, Harinder Singh
Summary: Pollution and contamination of water with heavy metals is a global challenge. Grafting poly-functional groups on polysaccharide chains can improve the adsorption affinities towards heavy metals. Aerogels, as three-dimensional porous materials, have gained attention for heavy metal removal from wastewater. This review critically analyzes the synthesis routes, physico-chemical characterizations, and removal mechanisms of cellulose-based aerogels for heavy metal ions adsorption. Challenges and future research directions for the development of efficient cellulose aerogels are also discussed.
Article
Engineering, Biomedical
Nikhil Anand, Kaushik Pal
Summary: This study improves the mechanical properties and degradation rate of Zn-Mg composite by adding alloying elements Mn and HA, as well as a polymer-ceramics nanofiber coating. The coated samples show excellent blood and cell compatibility.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2022)
Article
Astronomy & Astrophysics
Xiaomei Lu, Yongxiang Hu, Yuekui Yang, Mark Vaughan, Stephen Palm, Charles Trepte, Ali Omar, Patricia Lucker, Rosemary Baize
Summary: Afterpulsing effects in the ATLAS instrument on ICESat-2 satellite can impact the accurate measurement of low level signals and potentially degrade energy resolution. By analyzing on-orbit measurements in different seasons and geographic regions, the characteristics of afterpulsing effects in ATLAS PMTs can be understood, along with their potential impacts on altimetry and ocean subsurface retrievals.
EARTH AND SPACE SCIENCE
(2021)
Article
Green & Sustainable Science & Technology
John R. Mason, Joanna N. Weyrich, Hongwei Yang
Summary: The study investigates the influence of adding varying amounts of liquid on the formation of metal-organic framework Cu-3(BTC)(2) and its porosity during mechanochemical synthesis. Experimental results show that an increase in liquid during liquid-assisted grinding (LAG) process leads to larger microporosity in Cu-3(BTC)(2).
Proceedings Paper
Electrochemistry
J. Jakumeit, H. Behnken, R. Laqua, S. Mbewou, M. Fehlbier, J. Gaenz, L. Becker
Summary: High-pressure die casting (HPDC) is an important production process for large, thin-walled components. Simulation-based process optimization requires a combined modeling approach to fully capture potential defects.
LIGHT METALS 2021, 50TH EDITION
(2021)
Article
Chemistry, Physical
Elham Nazari Zadeh, Samieh Fozooni, Esmat Tavakkoli Nejad, Moj Khaleghi
Summary: Many recent studies have focused on mesoporous materials and clay minerals for their applications in drug delivery and heavy metal removal. A new compound called ethyl 2-((3-(triethoxysilyl)propylamino)(phenyl)methyl)-3-oxobutanoate (ETPO) was synthesized and used to modify MCM-41 and kaolinite. The modified composites were evaluated for their ability to remove Pb+2 and Cd+2 from water, and the optimal conditions were determined using response surface methodology. The results showed high removal efficiencies for both metals using the modified kaolinite and Fe3O4@MCM-41 adsorbents. Additionally, kaolinite modified with ETPO was employed as a carrier for propranolol and its drug release behavior was studied.
Article
Geosciences, Multidisciplinary
Clara Maurel, James F. J. Bryson, Jay Shah, Rajesh V. Chopdekar, Linda T. Elkins-Tanton, Carol A. Raymond, Benjamin P. Weiss
Summary: The presence of various iron meteorite groups indicates the melting and metal-silicate segregation of some planetesimals, resulting in metallic cores. Meteorite paleomagnetic records suggest that the crystallization of these cores generated dynamo magnetic fields. Studying the magnetic history of the partially differentiated IIE iron meteorite parent body reveals that its core likely generated a dynamo magnetic field powered by core crystallization, lasting for at least 80 million years. This suggests efficient core formation within some partially differentiated planetesimals.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Zhongtian Zhang, David Bercovici, Jacob S. Jordan
Summary: The study focuses on the internal evolution of Mars and suggests that Mars likely experienced at least one giant impact that caused complete melting and erased heterogeneity acquired from its component planetary embryos. This is in contrast to the initial hypothesis that Mars may have been a stranded planetary embryo, emphasizing the importance of collision events in the accretion process of planetary formation.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2021)
Article
Engineering, Multidisciplinary
Jodie B. Ream, Benjamin P. Weiss, Rona Oran, Carol A. Raymond, Carol A. Polanskey, Daniel D. Wenkert, Linda T. Elkins-Tanton, Richard A. Hart, Christopher T. Russell, Jose M. G. Merayo
Summary: Accurate measurements of ambient planetary and interplanetary magnetic fields can be challenging due to interference from spacecraft flight systems. This study presents an alternative method, called gradiometry peak suppression, which uses magnetic gradiometers to identify and suppress dominant frequencies generated by the flight system without affecting the spectral peaks of the ambient field. The method was successfully applied to both modeled data and actual Venus Express magnetometer data.
MEASUREMENT SCIENCE AND TECHNOLOGY
(2022)
Article
Geochemistry & Geophysics
J. M. Christoph, G. M. Minesinger, C. Bu, C. A. Dukes, L. T. Elkins-Tanton
Summary: Space weathering is a crucial process for understanding airless planetary surfaces. This study focuses on the effects of solar-wind ions on meteoritic troilite and finds that sulfur depletion rates are similar for different ion species. The study also quantifies sulfur diffusion, sputtering yield, and altered-layer composition.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Geochemistry & Geophysics
Zhongtian Zhang, David Bercovici, Linda Elkins-Tanton
Summary: Many asteroids may have been shattered by collisions and reaccumulated into porous rubble piles, with a negative correlation between size and porosity for stony asteroids, and suspected metallic asteroids showing larger porosities. Our models suggest that compaction between boulders occurs through cataclastic fracturing for silicate/chondritic boulders, while cold welding and deformation play a role in metal boulders.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2022)
Article
Geochemistry & Geophysics
Zhongtian Zhang, David Bercovici, Linda T. Elkins-Tanton
Summary: Primitive achondrites are residual mantle material of planetesimal objects, which experienced up to 20% partial melting. Melting experiments suggest that the resulting melts are rich in silica and alkali elements and are highly viscous. The percolation models suggest limited migration of these melts over timescales of 1-10 Myr. However, collisions between planetesimals in the early solar system may have shattered them into fragments, allowing for rapid melt migration in rubble-pile planetesimals.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Astronomy & Astrophysics
S. D. Dibb, J. F. Bell III, L. T. Elkins-Tanton, D. A. Williams
Summary: The NASA Psyche mission aims to study the structure, composition, and properties of asteroid (16) Psyche in order to test hypotheses about its formation. Based on observations, Psyche is believed to have a highly metallic composition with mafic silicate minerals distributed on the surface. The mission's Multispectral Imager will map the surface and provide compositional information using different filters.
EARTH AND SPACE SCIENCE
(2023)
Article
Astronomy & Astrophysics
Kevin M. Hubbard, Christopher W. Haberle, Linda T. Elkins-Tanton, Phillip R. Christensen, Steven Semken
Summary: Graybody materials have low emissivity across their spectrum, which violates the assumption of unit emissivity at some wavenumber used in calibrating thermal-infrared emission data. A new measurement technique is introduced to derive the absolute emissivity of graybody materials using reference samples with known Christiansen Frequencies. After correcting the temperature, pyrrhotite's emission spectrum is found to be spectrally featureless with a maximum emissivity of about 0.7.
EARTH AND SPACE SCIENCE
(2023)
Article
Astronomy & Astrophysics
Zhongtian Zhang
Summary: The transport of vapor inside a planetesimal can explain the oxidation states of iron meteorites and reconcile the snowline model for noncarbonaceous/carbonaceous planetesimal formation with observations.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Multidisciplinary Sciences
Zhongtian Zhang, David Bercovici
Summary: Paleomagnetic records of IVA group iron meteorites suggest the presence of an internal magnetic field in their parent body. However, the origin of this magnetism remains unclear due to the inhibitory effect of inward solidification on convection and dynamo activity. A possible scenario proposed by researchers suggests that the formation of a metal asteroid involves a disruptive collision that strips the mantle and reaccretes metal fragments. It is hypothesized that some of these fragments may have cooled before reaccretion, forming a cold inner core that extracts heat from the liquid layer and triggers solidification, leading to the expulsion of light elements and the generation of a dynamo. The portions of the crust that cooled below the remanence acquisition temperature would record the magnetic field.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Astronomy & Astrophysics
Carver J. Bierson, Linda T. Elkins-Tanton, Joseph G. O'Rourke
Summary: This article models the surface temperatures of asteroid 16 Psyche, predictig large thermal variations that may lead to cracking of boulders and the formation of a porous surface regolith. The study also suggests that water ice is unlikely to be stable at any latitude on 16 Psyche.
PLANETARY SCIENCE JOURNAL
(2022)