Results 61 to 70 of about 801,196 (212)

Quality from Kent: Preliminary results from the analysis of fifth‐ to seventh‐century silver alloys

Archaeometry, EarlyView.
Abstract This paper explores early results from the chemical and lead isotope analysis of 30 silver‐alloy objects from southeast England dating between the fifth and seventh centuries CE, presenting limited aspects of the three main analyses that were conducted. First, a comparison of the results gained from surface x‐ray fluorescence (pXRF) values and
Toby F. Martin, Matthew J. Ponting
wiley   +1 more source

The Provenance of Silver in the Viking‐Age Hoard From Bedale, North Yorkshire

Archaeometry, EarlyView.
ABSTRACT The acquisition of silver was a key motive propelling the Viking expansion out of Scandinavia; identifying the sources of Viking silver during the early part of the Viking Age can provide critical insights into the relative significance of western European and eastern, Islamic wealth in the Viking expansion.
Jane Kershaw, Stephen Merkel, Andrew Woods, Jane Evans, Vanessa Pashley, Simon Chenery   +5 more
wiley   +1 more source

Response of Remote Tropical West Pacific Islands to Climate Variability: A Multiproxy Record From T‐Lake, Palau, Spanning the Early Holocene to Present

Archaeometry, EarlyView.
ABSTRACT Lake sediments are natural archives of past environmental dynamics and how these systems have responded to past climate variability. Sediment geochemistry, governed by local geology and climate processes, is unique to each lake‐catchment and geochemical proxies must be validated for each study site.
Jalene Nalbant, Larissa Schneider, Jessica L. Blois, Matthew Wolhowe, Julian P. Sachs, Simon G. Haberle, Geoffrey Clark   +6 more
wiley   +1 more source

Zoning and contamination rate of magnesium and heavy metals of iron, zinc and copper in the north and northwest aquifer of Khoy (Zourabad) based on GIS and determining the contaminated source

Journal of Economic Geology, 2015
Introduction Heavy metals are the most toxic pollutants in aquatic ecosystems. This contamination can result from the release of heavy metal elements during alteration and weathering of ultramafic and mafic rocks (ophiolite zones).
Fariborz Khodadadi, Abdolnaser Fazlnia, Hossein Pirkharrati   +2 more
doaj  

Droughts and human impact in the ancient Uaymil region of the Maya lowlands inferred from a 2800‐year sedimentary archive at Lake Kaná, Mexico

Boreas, EarlyView.
The relationship between the climate and societal transformation in Maya lowlands has long been debated, particularly the role of drought in shaping the civilization trajectory during the Classic Period. A high‐resolution, multi‐proxy, geochemical record from Lake Kaná, located in the underexplored Uaymil region of the Yucatán Peninsula in Mexico ...
Haydar B. Martinez‐Dyrzo, Priyadarsi D. Roy, Benjamin Gwinneth, Irma G. Vargas‐Martinez, Alejandro A. Aragon‐Moreno, Roger Medina‐Gonzales   +5 more
wiley   +1 more source

Impurity Diffusion and Isotope Effect of Cobalt in α-Iron

Materials Transactions, JIM, 1993
Impurity diffusion and the isotope effect of cobalt in α-iron have been studied by a serial radio-frequency sputter-microsectioning method with radioactive tracers 57 Co and 60 Co in the temperature range 859 to 1173 K. of the magnetic spin ordering on the diffusion of cobalt than that on the self-diffusion in α-iron has been observed.
Yoshiaki Iijima, Kazuhiro Kimura, Chan-Gyu Lee, Ken-ichi Hirano   +3 more
openaire   +2 more sources

δ13C and δ15N Values of Residues Provide Insights Into Identification of the Explosive Source

Rapid Communications in Mass Spectrometry, Volume 40, Issue 10, 30 May 2026.
ABSTRACT Rationale Postblast analyses of military and terrorist events will benefit from the capacity to learn more about the explosive materials used in an event. Here stable isotope ratio analyses (δ13C, δ15N) can provide additional information to complement identification of the explosive components.
James R. Ehleringer, John D. Howa
wiley   +1 more source

Asymmetric Negishi and Kumada Couplings

Advanced Synthesis &Catalysis, Volume 368, Issue 5, 3 March 2026.
This review summarizes asymmetric Negishi and Kumada cross‐coupling reactions from the 1980s through 2025. It examines enantioselective and enantiospecific transformations catalyzed by nickel, palladium, and cobalt complexes , highlighting ligand design, mechanistic insights, and applications in constructing complex chiral molecules and natural ...
Rui‐Heng Wang, Aishun Ding, Ramon Rios
wiley   +1 more source

Cobalt‐Salen Catalysed Hydration of Alkenes With Water: A Complementary Ionic Approach to the Mukaiyama Hydration

Advanced Synthesis &Catalysis, Volume 368, Issue 5, 3 March 2026.
A cobalt‐salen catalysed hydration of olefins with water is reported, resulting in Markovnikov alcohol products. The reaction proceeds rapidly under mild conditions and exhibits excellent functional group tolerance, supporting a wide range of styrenyl and non‐activated alkenes.
David G. Groves, Reece H. Hoogesteger, Balakumar Emayavaramban, Craig P. Johnston   +3 more
wiley   +1 more source

Beyond Sabatier: Multiplicate Spillover Phenomena for Manipulating Catalytic Dynamics in Various Electrocatalysis

Advanced Science, Volume 13, Issue 13, 3 March 2026.
Various spillover‐mediated electrocatalytic reactions, such as hydrogen and oxygen evolution, carbon dioxide and nitrogen reduction, and methanol oxidization reactions, are systematically summarized. Abstract Spillover phenomenon, which is characterized by the dynamic migration of active species across catalyst surfaces, provides a promising avenue to ...
Di Wang, Ziyou Dong, Qianqian Yao, Shixue Dou, Jun Mei, Ziqi Sun   +5 more
wiley   +1 more source