scholarly journals Micro-scale dissolution seams mobilise carbon in deep-sea limestones

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Christoph E. Schrank ◽  
Michael M. W. Jones ◽  
Cameron M. Kewish ◽  
Grant A. van Riessen ◽  
Kathryn E. Elphick ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Deep Sea ◽  
Carbon Sink ◽  
Bulk Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcite Cement ◽  
Diffraction Microscopy

AbstractMeasuring the amount of carbon captured in deep-sea limestones is fundamental to understanding the long-term carbon cycle because pelagic limestones represent Earth’s largest carbon sink since the mid-Mesozoic. However, their contribution to the long-term carbon cycle is poorly quantified. Here, we use X-ray fluorescence and scanning X-ray diffraction microscopy for high-resolution chemical and structural analysis of pelagic limestone from the Paleocene Kaiwhata Formation in New Zealand. We identify densely packed diagenetic micro-dissolution seams that are invisible to light and electron-beam microscopes in most cases. Mass-balance calculations indicate that individual seams remove ~50% of the calcite mud matrix while their bulk-sample carbon loss adds up to ~10%. The liberated carbon is trapped in situ as calcite cement or returned to the ocean during physical compaction or soft-sediment deformation. We suggest micro-dissolution structures may play an important role in the long-term carbon cycle by modulating carbon exchange between the geosphere and hydrosphere.

Rechargeable nonaqueous lithium/Mo6S8 battery

1984 ◽  
Vol 62 (6) ◽  
pp. 527-531 ◽  
Author(s):  
P. J. Mulhern ◽  
R. R. Haering
Keyword(s):  
Discharge Rate ◽  
Active Material ◽  
Rate Capability ◽  
Constant Current ◽  
Electrochemical Cells ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Cycle Life

Electrochemical cells based on the intercalation of lithium into Mo6S8 were examined by derivative constant current chronopotentiometry, in situ X-ray diffraction, and long-term cycling. About three-quarters of the capacity of such cells oeeurs between 2.0 and 2.1 V with most of the remainder near 2.45 V. Li/Mo6S8 cells have a long cycle life, good discharge rate capability, and an energy density of at least 260 W∙h/kg (1 W∙h = 3.6 kJ) of active material. Such cells can be made by starting with cathodes made from ternary Chevrel phase compounds. AyMo6S8 (A = Cu, Fe, Ni), and electrochemically converting these materials to form LixMo6S8.

Zeolite - Salt Occlusion: A Potential Route for the Immobilisation of Iodine-129?

2003 ◽  
Vol 807 ◽  
Author(s):  
Neil C. Hyatt ◽  
Joseph A. Hriljac ◽  
Alia Choudhry ◽  
Laura Malpass ◽  
Gareth P. Sheppard ◽  
...  
Keyword(s):  
Weight Loss ◽  
Uniform Distribution ◽  
Crystalline Phase ◽  
Thermally Stable ◽  
X Ray Diffraction ◽  
Single Crystalline ◽  
X Ray ◽  
Elemental Silver

ABSTRACTReactions of zeolite Na-A with AgI, and the sodium, copper and lead forms of zeolites A, LTA, X and Y with NaI, have been examined as possible starting routes to the long term immobilisation of iodine-129. Heating the salts in air, at 500°C, with the sodium forms of the zeolites leads to the formation of occlusion products, where the iodide salt migrates into the zeolite pores. Detailed studies of the Na-A / 5AgI complex indicate it has a uniform distribution of Na, Si, Al, Ag and I, and is thermally stable to ca. 750°C, where there is a substantial weight loss as iodine is released. In situ powder X-ray diffraction studies have been used to monitor the occlusion reaction at 400°C, and show that the occlusion product decomposes to produce a single crystalline phase at 800°C prior to further decomposition at 850°C to a mixture of nepheline and elemental silver.

scholarly journals Upper Paleocene ultramafic igneous rocks offshore mid-Norway: Reinterpretation of the Vestbrona Formation as a sill complex

2017 ◽  
Vol 5 (3) ◽  
pp. SK103-SK120 ◽  
Author(s):  
Amer Hafeez ◽  
Sverre Planke ◽  
Dougal A. Jerram ◽  
John M. Millett ◽  
Dwarika Maharjan ◽  
...  
Keyword(s):  
Igneous Rocks ◽  
Contact Metamorphism ◽  
X Ray Diffraction ◽  
Sediment Samples ◽  
X Ray ◽  
Stratigraphic Framework ◽  
Northwest Europe ◽  
Migration Pathways

Continental breakup between northwest Europe and Greenland (approximately 56 Ma) was associated with widespread magmatism. Silica undersaturated alkaline porphyritic igneous rocks of a similar age have previously been dredged near the mid-Norwegian coast. These igneous rocks of the Vestbrona Formation have previously been interpreted as either igneous plugs or volcanic flows. New 3D seismic data indicate that relatively small sill complexes are abundant in the same region. In total, 36 sills with a size of [Formula: see text] have been mapped. In addition, 10 seismic horizons were interpreted and tied to nearby wells to obtain a robust stratigraphic framework. The sills mainly intrude Cretaceous and Paleocene sequences; however, one sill is also identified in the pre-Cretaceous sequences. The sills locally form erosional remnants on the seabed due to massive uplifting and erosion of the continental margin. Vintage igneous and sedimentary dredge samples have been reanalyzed, including petrography, geochemistry (X-ray fluorescence [XRF], X-ray diffraction [XRD]), biostratigraphy, and Ar-Ar geochronology. The new Ar-Ar data suggest that the sills are 1–2 Ma older than breakup (approximately 57–58 Ma). Furthermore, the biostratigraphy and petrography of two sediment samples suggest that the samples were collected from near in situ subcrops and not of an ice rafted origin. The sediment samples are of Danian age and are strongly metamorphosed, most likely by contact metamorphism resulting from heating during sill emplacement. The newly identified sills have implications for the petroleum prospectivity of the study area including source rock maturation within thermal aureoles and the long-term alteration of fluid migration pathways.

In situmonitoring of powder reactions in percolating solution by wet-cell X-ray diffraction techniques

2003 ◽  
Vol 36 (3) ◽  
pp. 948-949 ◽  
Author(s):  
Laurence N. Warr ◽  
Heiko Hofmann
Keyword(s):  
Open Systems ◽  
Reaction Chamber ◽  
Solution Chemistry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Standard Powder ◽  
Flow Through ◽  
Kinetics Of

This note describes how the kinetics of powder reactions in percolating solution can be studied by X-ray diffraction using a wet-cell flow-through reaction chamber. The device can be routinely moved between diffractometer and controlled laboratory (pressure, temperature) conditions with the ease of a standard powder holder. Short-termin situmeasurements and long-termquasiin situmonitoring of dissolution and crystallization reactions are possible with a minimum of sample preparation and little disturbance of the system. Measuring time-dependent changes in the concentration of crystalline reactants and products provides information for quantifying reaction kinetics and for determining dissolution and crystal growth mechanisms. Results can be compared with changes in solution chemistry of the collected eluate, enabling a more complete reconstruction of heterogeneous crystal–solution reactions in open systems.

scholarly journals Aluminum Alloys with the Addition of Reduced Deep-Sea Nodules

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 421
Author(s):  
Alena Michalcová ◽  
Matouš Orlíček ◽  
Pavel Novák
Keyword(s):  
Aluminum Alloys ◽  
Deep Sea ◽  
Energy Dispersive Spectrometer ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Manganese Nodules ◽  
X Ray ◽  
Good Thermal Stability ◽  
Scanning Electron

An innovative way to utilize deep-sea manganese nodules is described in this paper. The manganese nodules were reduced by aluminothermy and subsequently added into aluminum as a mixture of alloying elements in their natural ratio. The microstructure and properties of aluminum alloys containing 1.2, 7.7, and 9.7 wt % of reduced nodules were studied. The alloys were formed by Al matrix and minor amounts of Al6(Fe,Mn) and Al11Fe7 intermetallic phases. The alloys containing a higher amount of reduced nodules are characterized by very good thermal stability. The obtained alloys were studied by X-ray diffraction, their microstructure was observed by scanning electron microscopy, and their local chemical composition was analyzed by energy dispersive spectrometer. The hardness of the samples was measured on the initial materials and after long-term annealing. Based on the obtained results, the aluminum alloys, with the addition of reduced deep-sea nodules, can serve as precursors for processing, e.g., by rapid solidification or hot working methods.

scholarly journals Observation of electromigration in a Cu thin line by in situ coherent x-ray diffraction microscopy

2009 ◽  
Vol 105 (12) ◽  
pp. 124911 ◽  
Author(s):  
Yukio Takahashi ◽  
Yoshinori Nishino ◽  
Hayato Furukawa ◽  
Hideto Kubo ◽  
Kazuto Yamauchi ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
Thin Line ◽  
Diffraction Microscopy

scholarly journals Study of slip activity in a Mg-Y alloy by in situ high energy X-ray diffraction microscopy and elastic viscoplastic self-consistent modeling

2018 ◽  
Vol 155 ◽  
pp. 138-152 ◽  
Author(s):  
Leyun Wang ◽  
Zhonghe Huang ◽  
Huamiao Wang ◽  
Alireza Maldar ◽  
Sangbong Yi ◽  
...  
Keyword(s):  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slip Activity ◽  
Self Consistent ◽  
Diffraction Microscopy
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