Co-response of Fe-reducing/oxidizing bacteria and Fe species to the dynamic redox cycles of natural sediment

2022 ◽  
pp. 152953
Author(s):  
Rong Chen ◽  
Hui Liu ◽  
Peng Zhang ◽  
Jie Ma ◽  
Menggui Jin
Keyword(s):  
Natural Sediment ◽  
Redox Cycles ◽  
Fe Species

scholarly journals A Novel Method for the Preparation of Fibrous CeO2–ZrO2–Y2O3 Compacts for Thermochemical Cycles

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 885
Author(s):  
Nicole Knoblauch ◽  
Peter Mechnich
Keyword(s):  
Large Scale ◽  
Preparation Method ◽  
Cost Effective ◽  
High Porosity ◽  
Thermochemical Cycles ◽  
Redox Cycles ◽  
Redox Kinetics ◽  
Direct Infiltration ◽  
Novel Method ◽  
Functional Components

Zirconium-Yttrium-co-doped ceria (Ce0.85Zr0.13Y0.02O1.99) compacts consisting of fibers with diameters in the range of 8–10 µm have been successfully prepared by direct infiltration of commercial YSZ fibers with a cerium oxide matrix and subsequent sintering. The resulting chemically homogeneous fiber-compacts are sinter-resistant up to 1923 K and retain a high porosity of around 58 vol% and a permeability of 1.6–3.3 × 10−10 m² at a pressure gradient of 100–500 kPa. The fiber-compacts show a high potential for the application in thermochemical redox cycling due its fast redox kinetics. The first evaluation of redox kinetics shows that the relaxation time of oxidation is five times faster than that of dense samples of the same composition. The improved gas exchange due to the high porosity also allows higher reduction rates, which enable higher hydrogen yields in thermochemical water-splitting redox cycles. The presented cost-effective fiber-compact preparation method is considered very promising for manufacturing large-scale functional components for solar-thermal high-temperature reactors.

scholarly journals EXAFS Determination of Clay Minerals in Martian Meteorite Allan Hills 84001 and Its Implication for the Noachian Aqueous Environment

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 176
Author(s):  
Ryoichi Nakada ◽  
Gaku Tanabe ◽  
Iori Kajitani ◽  
Tomohiro Usui ◽  
Masashi Shidare ◽  
...  
Keyword(s):  
Silica Glass ◽  
Large Body ◽  
Aqueous Environment ◽  
Martian Surface ◽  
Exafs Analysis ◽  
Martian Meteorite ◽  
Fe Species ◽  
Allan Hills 84001 ◽  
X Ray Absorption

The aqueous environment of ancient Mars is of significant interest because of evidence suggesting the presence of a large body of liquid water on the surface at ~4 Ga, which differs significantly from the modern dry and oxic Martian environment. In this study, we examined the Fe-bearing minerals in the 4 Ga Martian meteorite, Alan Hills (ALH) 84001, to reveal the ancient aqueous environment present during the formation of this meteorite. Extended X-ray absorption fine structure (EXAFS) analysis was conducted to determine the Fe species in ALH carbonate and silica glass with a high spatial resolution (~1–2 μm). The μ-EXAFS analysis of ALH carbonate showed that the Fe species in the carbonate were dominated by a magnesite-siderite solid solution. Our analysis suggests the presence of smectite group clay in the carbonate, which is consistent with the results of previous thermochemical modeling. We also found serpentine in the silica glass, indicating the decrease of water after the formation of carbonate, at least locally. The possible allochthonous origin of the hematite in the carbonate suggests a patchy redox environment on the ancient Martian surface.

Effects of natural sediment features on survival of the phoxocephalid amphipod, Rhepoxynius abronius

1988 ◽  
Vol 25 (2) ◽  
pp. 99-124 ◽  
Author(s):  
Theodore H. DeWitt ◽  
George R. Ditsworth ◽  
Richard C. Swartz
Keyword(s):  
Natural Sediment

Analysis of Fe species in zeolites by UV–VIS–NIR, IR spectra and voltammetry. Effect of preparation, Fe loading and zeolite type

2005 ◽  
Vol 80 (1-3) ◽  
pp. 279-289 ◽  
Author(s):  
L. Čapek ◽  
V. Kreibich ◽  
J. Dědeček ◽  
T. Grygar ◽  
B. Wichterlová ◽  
...  
Keyword(s):  
Ir Spectra ◽  
Fe Species ◽  
Zeolite Type

Oxidative DNA Damage Induced by Benz[a]anthracene Metabolites via Redox Cycles of Quinone and Unique Non-Quinone

2003 ◽  
Vol 16 (11) ◽  
pp. 1470-1476 ◽  
Author(s):  
Kazuharu Seike ◽  
Mariko Murata ◽  
Shinji Oikawa ◽  
Yusuke Hiraku ◽  
Kazutaka Hirakawa ◽  
...  
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Redox Cycles
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