Lubrication in Desert Environments: Oil-Soluble Organo-Silver Molecules Designed for In-Situ Deposition of Metallic Silver at High Temperatures

Author(s):  
Hassan S. Bazzi ◽  
Afif Seyam ◽  
Black Johnson ◽  
Michael Desanker ◽  
Yip-Wah Chung ◽  
...  
2016 ◽  
Vol 8 (21) ◽  
pp. 13637-13645 ◽  
Author(s):  
Michael Desanker ◽  
Blake Johnson ◽  
Afif M. Seyam ◽  
Yip-Wah Chung ◽  
Hassan S. Bazzi ◽  
...  

Author(s):  
Z. L. Wang ◽  
J. Bentley

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.


2021 ◽  
Vol 546 ◽  
pp. 149019
Author(s):  
Bao Jin ◽  
Jun Zhao ◽  
Guangyan Chen ◽  
Yongyong He ◽  
Yiyao Huang ◽  
...  

Author(s):  
Sheila Shahidi ◽  
Sanaz Dalalsharifi ◽  
Mahmood Ghoranneviss ◽  
Rattanaphol Mongkholrattanasit

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lucas C. R. Silva ◽  
Rodrigo Studart Corrêa ◽  
Jamie L. Wright ◽  
Barbara Bomfim ◽  
Lauren Hendricks ◽  
...  

AbstractAmazonian Dark Earths (ADEs) are unusually fertile soils characterised by elevated concentrations of microscopic charcoal particles, which confer their distinctive colouration. Frequent occurrences of pre-Columbian artefacts at ADE sites led to their ubiquitous classification as Anthrosols (soils of anthropic origin). However, it remains unclear how indigenous peoples created areas of high fertility in one of the most nutrient-impoverished environments on Earth. Here, we report new data from a well-studied ADE site in the Brazilian Amazon, which compel us to reconsider its anthropic origin. The amounts of phosphorus and calcium—two of the least abundant macronutrients in the region—are orders of magnitude higher in ADE profiles than in the surrounding soil. The elevated levels of phosphorus and calcium, which are often interpreted as evidence of human activity at other sites, correlate spatially with trace elements that indicate exogenous mineral sources rather than in situ deposition. Stable isotope ratios of neodymium, strontium, and radiocarbon activity of microcharcoal particles also indicate exogenous inputs from alluvial deposition of carbon and mineral elements to ADE profiles,  beginning several thousands of years before the earliest evidence of soil management for plant cultivation in the region. Our data suggest that indigenous peoples harnessed natural processes of landscape formation, which led to the unique properties of ADEs, but were not responsible for their genesis. If corroborated elsewhere, this hypothesis would transform our understanding of human influence in Amazonia, opening new frontiers for the sustainable use of tropical landscapes going forward.


1998 ◽  
Vol 299 (1-2) ◽  
pp. 15-22 ◽  
Author(s):  
A Canesi ◽  
M.R Cimberle ◽  
C Ferdeghini ◽  
A Diaspro ◽  
P Guasconi ◽  
...  

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