A5070728761- Astro and Planetary Science
- Planetary Science and Exploration
- Geological and Geochemical Analysis
- Isotope Analysis in Ecology
- Ion-surface interactions and analysis
- Geology and Paleoclimatology Research
- High-pressure geophysics and materials
- Spacecraft and Cryogenic Technologies
- Methane Hydrates and Related Phenomena
- Nuclear Physics and Applications
- Paleontology and Stratigraphy of Fossils
- Space Exploration and Technology
- X-ray Spectroscopy and Fluorescence Analysis
- Microbial Community Ecology and Physiology
- X-ray Diffraction in Crystallography
- earthquake and tectonic studies
- Cryospheric studies and observations
- Polar Research and Ecology
- Gear and Bearing Dynamics Analysis
- Fluid Dynamics and Vibration Analysis
- Coral and Marine Ecosystems Studies
- Genomics and Phylogenetic Studies
- Geological Studies and Exploration
- Mineralogy and Gemology Studies
- Powder Metallurgy Techniques and Materials
Japan Steel Works (Japan)
2017-2024
Toyo Engineering (Japan)
2022-2024
High Energy Accelerator Research Organization
2024
Yokohama National University
2010-2021
Japan Agency for Marine-Earth Science and Technology
2021
Kyoto University
2014
Yamagata Prefectural Education Institute
2014
Suzuki (Japan)
2014
Tohoku University
2014
Okayama Prefecture
2014
Abstract Volatile and organic-rich C-type asteroids may have been one of the main sources Earth’s water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but meteorite record biased: only strongest types survive atmospheric entry are then modified interaction with terrestrial environment. Here we present results a detailed bulk microanalytical study pristine Ryugu particles, brought to Earth Hayabusa2 spacecraft. particles display close...
Abstract A dense magnesium iron silicate polymorph with a structure intermediate between olivine, ringwoodite, and wadsleyite was theoretically predicted about four decades ago. As this group of minerals constitute the major component shocked meteorites, constraining their transitional forms behaviour is potential importance for understanding impact events on parent bodies. Here we use high-resolution transmission electron microscopy techniques single-crystal X-ray diffraction analyses to...
Abstract The delivery of water to the inner Solar System, including Earth, is still a debated topic. A preferential role for hydrated asteroids in this process supported by isotopic measurements. Carbonaceous chondrite (CC) meteorites represent our main source information about these volatile-rich asteroids. However, destruction weaker materials during atmospheric entry creates bias CC data. return surface from C-type asteroid 162173 Ryugu Hayabusa2 spacecraft provides unique opportunity...
Abstract Micrometeorites, a possible major source of Earth’s water, are thought to form from explosive dispersal hydrated chondritic materials during impact events on their parental asteroids. However, this provenance and formation mechanism have yet be directly confirmed using asteroid returned samples. Here, we report evidence mild shock metamorphism in the surface particles Ryugu based electron microscopy. All dominated by phyllosilicates but lack dehydration textures, which indicative...
Discovery of fossil asteroidal ice in a meteorite provides new insight into asteroid formation the early Solar System.
Although environmental changes and evolution of life are potentially recorded via microbial carbonates, including laminated stromatolites clotted thrombolites, factors controlling their fabric still a matter controversy. Herein, we report that the exopolymer properties different cyanobacterial taxa primarily control carbonates fabrics in modern examples. This study shows calcite encrustation filamentous Phormidium sp. secreting acidic exopolymers forms stromatolites, whereas coccoid...
Abstract We developed universal sample holders [the Kochi grid, clamp, and Okazaki cell) a transfer vessel (facility-to-facility container (FFTC)] to analyze sensitive fragile samples, such as extremely small extraterrestrial materials. The prevent degradation, contamination due the terrestrial atmosphere (water vapor oxygen gas) particles, well mechanical damage. FFTC can isolate samples from effects of for more than week. grid clamp were made coordinated micro/nano-analysis that utilizes...
Abstract Although CI chondrites are susceptible to terrestrial weathering on Earth, the specific processes unknown. To elucidate mechanism, we conduct a laboratory experiment using pristine particles from asteroid Ryugu. Air‐exposed predominantly develop small‐sized euhedral Ca‐S‐rich grains (0.5–1 μm) particle surface and along open cracks. Both transmission electron microscopy synchrotron‐based computed tomography combined with XRD reveal that hydrous Ca‐sulfate. Notably, this phase does...
Abstract Shock‐induced melting textures and high‐pressure polymorphs in 178 ordinary chondrites of all chemical groups petrologic types were investigated. The shock‐induced modes classified into three types, namely pocket, line, network. type depends on the type. width melt increased with increasing number. approximate estimated shock‐pressure ranges recorded around melts H‐group based identified as follows: H3, less than 2 GPa; H4–H6, 2–6 GPa. For L/LL group, values L/LL3, L/LL4, 2–14 L5:...
<title>Abstract</title> Solar system abundances of the elements, which are determined by spectroscopic measurements solar photosphere and laboratory analyses CI (Ivuna-type) carbonaceous chondrites, a cornerstone to understand origin evolution planets other constituents, such as asteroids comets. Mercury (Hg) is one elements whose abundance still poorly constrained due no observable lines for Hg in spectrum large variations chondrites caused mainly terrestrial contamination. Here we...
Abstract We investigated the back‐transformation mechanisms of ringwoodite and majorite occurring in a shock‐melt vein (SMV) Yamato 75267 H6 ordinary chondrite during atmospheric entry heating. Ringwoodite shock melt near fusion crust have back‐transformed into olivine enstatite, respectively. (Fa ~18 ) occurs SMV as fine‐grained polycrystalline assemblage. Approaching crust, becomes dominant instead ringwoodite. The from to proceeds by incoherent nucleation an interface‐controlled growth...
Chemosynthetic organisms flourish around deep-sea hydrothermal vents where energy-rich fluids are emitted from metal sulfide chimneys. However, microbial life hosted in mineral assemblages extinct chimneys lacking fluid venting remains largely unknown. The interior of anoxic the percolation oxygenated seawater is limited within tightly packed grains. Given scarcity photosynthetic organics deep seawater, anaerobic microbes might inhabit grain boundaries energetically depending on substrates...
Abstract The Almahata Sitta (AhS) meteorite is a unique polymict ureilite. Recently, carbonaceous chondritic lithologies were identified in AhS. Organic matter (OM) ubiquitously found primitive chondrites. molecular and isotopic characteristics of this OM reflect its origin parent body processes, are particularly sensitive to heating. C1 AhS 671 91A investigated, focusing mainly on the OM. We that these contains signatures, but experienced slight heating possibly by short‐term event(s)....
Abstract High‐pressure minerals in the eucrite Padvarninkai were investigated. Parts of anorthitic plagioclase and tridymite host rock vitrified, indicating that shock pressure was 22–27 GPa. Tissintite, coesite, a majorite‐bearing garnet occurred shock‐melt veins as high‐pressure minerals. kyanite, corundum, dense have grains. The melted tissintite crystallized from melt after crystallization kyanite corundum. residual became by quenching. Tridymite has also coesite melt. formation...
Abstract The (plagioclase) lherzolitic shergottite Northwest Africa (NWA) 7397 consists of poikilitic and non‐poikilitic lithologies. Coarse‐grained low‐Ca pyroxene oikocrysts enclose olivine chromite grains in the lithology. major constituents lithology are olivine, Ca‐pyroxene, plagioclase. Minor amounts chromite, ilmenite, alkali feldspar, Ca‐phosphate, iron‐sulfide included Most plagioclase have become maskelynite. A melt pocket occurs Plagioclase contact with has dissociated into...
Distributed processing system for restoration of electric power distribution network using two-layered CNP is proposed. The goal this study to develop the which adjusts future with distributed generators. state art that applied computing environment in practical use. has two classes agents, named field agent and operating network. In order avoid conflicts tasks, controls privilege managers send task announcement messages CNP. This technique realizes coordination between agents work...
A focused ion beam (FIB) scanning electron microscope (SEM) equipped with a low–energy Ar–ion gun, an back–scattered diffraction (EBSD) detector, and energy dispersive spectrometer (EDS) was newly developed for microfabrication, followed by submicroscopic chemical crystallographic analyses in identical sample chamber. The surface condition of mineral samples requires extreme care during FIB milling process, especially EBSD measurement, as the pattern is greatly affected damaged amorphous...
There has been some interest in the flow drag and heat transfer reduction effects of brine with surfactants order to achieve effective energy consumption an industrial cooling system. Therefore, there have our previous investigations (Ethylene Glycol (EG) solution for organic brine) surfactant (Oleyldihydroxyetyl Amine Oxide (ODEAO) non-ion surfactant) showing effect. But technical issues are that EG is environmentally harmful use will be restricted future. Whereas, Propylene (PG) Potassium...
Abstract We developed universal sample holders (the Kochi grid, clamp, and Okazaki cell) a transfer vessel (facility-to-facility container (FFTC)) to analyze sensitive fragile samples, such as extremely small extraterrestrial materials. The prevent degradation, contamination due terrestrial atmosphere (water vapor oxygen gas) particles, well mechanical damages. FFTC can isolate the samples from effects of for more than week. grid clamp were made coordinate micro/nano-analysis that utilize...