Results 41 to 50 of about 1,209 (113)

Gipsgärten: Selbstorganisierte röhrenförmige Strukturen aus Calciumsulfat mit Relevanz für die Suche nach außerirdischem Leben

open access: yesAngewandte Chemie, Volume 137, Issue 48, November 24, 2025.
Chemische Gärten sind selbstorganisierte abiotische Strukturen mit „lebensähnlichen” Formen. Hier zeigen wir, dass solche Prozesse auch nach Zugabe konzentrierter Sulfatlösungen zu festen Calciumsalzen ablaufen und sogenannte Gipsgärten ergeben. Die dafür nötigen Bedingungen sind weitgehend kompatibel mit den geochemischen Verhältnissen auf dem frühen ...
Selina Reigl   +5 more
wiley   +1 more source

Gypsum Gardens: Self‐Assembled Tubular Structures of Calcium Sulfate with Relevance for the Detection of Extraterrestrial Life

open access: yesAngewandte Chemie International Edition, Volume 64, Issue 48, November 24, 2025.
Chemical gardens are self‐assembled architectures with “life‐like” morphologies that form in the absence of any biological activity. Here we show that such structures can also be obtained by contacting reservoirs of calcium and sulfate ions, under conditions that plausibly emulate those prevailing on early Mars.
Selina Reigl   +5 more
wiley   +1 more source

Evaluation of Ceramic Properties of Bauxitic Materials from SE of Iberian Range

open access: yesChemEngineering
The use of aluminum-rich clays and bauxites as refractory materials is common. Upon firing, these materials form mullite crystals in the shape of needles embedded in a siliceous and vitreous matrix, with mullite being responsible for the refractory ...
Domingo Martín   +7 more
doaj   +1 more source

Modulation of the Acidity of HY, HBETA, and HZSM‐5 Zeolites by Lanthanum Incorporation for Selective Gasoline Desulfurization in the FCC Riser

open access: yesChemCatChem, Volume 17, Issue 21, November 10, 2025.
Desulfurization in the FCC riser is achieved by modifying zeolite catalysts with La3+ ions, promoting H2S formation from thiophenic compounds while suppressing secondary reactions. This approach enhances gasoline quality by increasing selectivity for H2S and enabling efficient condensation and alkylation, supporting cleaner fuel production and ...
Ronaldo C. Santos   +8 more
wiley   +1 more source

Informe sobre las investigaciones de arcilla hechas en los laboratorios de la Facultad Nacional de Minas

open access: yesBoletín Geológico, 1966
La investigación moderna de arcillas se basa en el estudio de la red molecular. En estos estudios se usan rayos X, ensayos termodiferenciales y exámenes con el microscopio electrónico.
Reinaldo Ellwanger
doaj   +1 more source

Mineralogical and geochemical characteristics of volcanic rocks of the Valles-San Luis Potosí platform, Mexico: Geodynamic implications

open access: yesGeofísica Internacional, 1996
La región, que abarca a la unidad paleogeográfica Mesozoica denominada Plataforma Valles-San Luis Potosí, tiene influencia volcánica tanto del dominio Cordillerano como del Golfo de México, por lo que es un área favorable para el estudio de los sucesivos
Juan José Valencia-Islas   +2 more
doaj   +1 more source

Optimized bifunctional CuNiMgAl catalysts for efficient synthesis of the renewable bioproduct glycerol carbonate

open access: yesBiofuels, Bioproducts and Biorefining, Volume 19, Issue 5, Page 1271-1288, September/October 2025.
Abstract This paper presents a novel technology for converting glycerol, a byproduct of the biodiesel industry, into glycerol carbonate, a high‐value bioproduct. The effect of calcination temperature on the synthesis of quaternary Cu‐Ni‐Mg‐Al catalysts (MMO‐Cu15Ni15‐Tz) and their application in the transesterification reaction was investigated ...
Dalma S. Argüello   +5 more
wiley   +1 more source

Memorias de la zona tórrida: el naturalismo clásico y la «tropicalidad» americana en el Sumario de la natural historia de las Indias de Gonzalo Fernández de Oviedo (1526)

open access: yesRevista de Indias, 2013
Este ensayo examina el papel que juega la «tropicalidad» en la taxonomía de la naturaleza y cultura americanas que ofrece Oviedo en el Sumario de la natural historia de las Indias (1526).
Nicolás Wey Gómez
doaj   +1 more source

Pd Nanoparticles Supported on Activated Carbon and Their Application in the Oxidative Condensation Reaction of Furfural: Effect of Base and Oxidizing Agent on Catalytic Behavior and Deactivation

open access: yesChemCatChem, Volume 17, Issue 17, September 5, 2025.
Catalysts with varying palladium (Pd) loading supported on activated carbon were assessed for their effectiveness in the oxidative condensation of furfural. Furan‐2‐acrolein was the primary product, depending on the palladium content. Reusability tests showed a decline in the yield of furan‐2‐acrolein.
Rocío Maderuelo Solera   +6 more
wiley   +1 more source

Enhanced Oxygen Evolution Reaction Performance of Niobium–Cobalt Oxide Catalysts in Acidic and Alkaline Media

open access: yesAdvanced Sustainable Systems, Volume 9, Issue 8, August 2025.
The electronic modulation of Nb‐doped Co3O4 catalyst showcases enhanced activity and extended stability for OER in both alkaline (1M KOH) and acidic (0.5M H2SO4) electrolytes. The higher activity emanated from the synergistic effect between the Nb5+ dopant and Co3O4.
Kassa Belay Ibrahim   +7 more
wiley   +1 more source

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