X-ray fluorescence core scanning, magnetic signatures, and organic geochemistry analyses of Ryukyu Trench sediments: turbidites and hemipelagites

AbstractThe southwestern Ryukyu Trench represents the ultimate sink of sediments shed from Taiwan into the Philippine Sea, which are mainly transported to the trench by turbidity currents via submarine canyons. Here, we present trench turbidites intercalated with hemipelagites in a gravity pilot core and a piston core acquired on the Ryukyu Trench floor at 6147 m water depth. We performed X-ray fluorescence core scans (ITRAX profiles), magnetic measurements, and organic geochemistry analyses to discriminate turbidites from hemipelagites. We identified 36 turbidites (0.9–4.2 cm thick) based on visual core descriptions and Ca/Fe ratios in the ITRAX profiles. Three of these turbidites show magnetic signatures indicating the presence of pyrrhotite and peaks in the magnetic susceptibility profile, suggesting that Taiwan-sourced sediments are transported to the Ryukyu Trench by long-runout turbidity currents. Pyrrhotite is also present in hemipelagites of the upper part of the retrieved cores, indicating a dominant sediment source in Taiwan over the last several thousand years. Ca/Fe and Zr/Rb ratios in the ITRAX profiles mark distal turbidites (about 1–3 cm thick), and Zr/Rb peaks mainly reflect grain size changes. Detailed analyses of a representative turbidite show good correlation between Ca/Fe and Zr/Rb peaks with upward-coarsening and upward-fining trends that delimit the turbidite. Sedimentary organic matter in hemipelagites is characterized by higher total organic carbon and total nitrogen contents and higher δ13C values than that in turbidites. Our multi-proxy approach employing high-resolution XRF core scans to differentiate turbidites from hemipelagites contributes to establishing a comprehensive view of modern trench sedimentation from Taiwan to the southwestern Ryukyu Trench.

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Interaction of ditertiary phosphines with phenyl- and 1-naphthyldithiocarbamatonickel(II)

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19851383 ◽

1985 ◽

Vol 50 (6) ◽

pp. 1383-1390

Author(s):

Aref A. M. Aly ◽

Ahmed A. Mohamed ◽

Mahmoud A. Mousa ◽

Mohamed El-Shabasy

Keyword(s):

Thermal Analysis ◽

Powder Diffraction ◽

Spin Structure ◽

Magnetic Measurements ◽

Mixed Ligand ◽

Mixed Ligand Complexes ◽

X Ray ◽

Square Planar

The synthesis of the following mixed ligand complexes is reported: [Ni(phdtc)2(dpm)2], [Ni(phdtc)2(dpe)2], [Ni(phdtc)2(dpp)3], [Ni(1-naphdtc)2(dpm)2], [Ni(1-naphdtc)2], and [Ni(1-naphdtc)2(dpp)2], where phdtc = PhNHCSS-, 1-naphdtc = 1-NaPhNHCSS-, dpm = Ph2PCH2PPh2, dpe = Ph2P(CH2)2PPh2, and dpp = Ph2P(CH2)3PPh2. The complexes are characterised by microanalysis, IR and UV-Vis spectra, magnetic measurements, conductivity, X-ray powder diffraction, and thermal analysis. All the mixed ligand complexes are diamagnetic, and thus a square-planar or square-pyramidal (low-spin) structure was proposed for the present complexes.

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Dissimilatory Iron-Reducing Microorganisms Are Present and Active in the Sediments of the Doce River and Tributaries Impacted by Iron Mine Tailings from the Collapsed Fundão Dam (Mariana, MG, Brazil)

Minerals ◽

10.3390/min11030244 ◽

2021 ◽

Vol 11 (3) ◽

pp. 244

Author(s):

Carolina N. Keim ◽

Jilder D. P. Serna ◽

Daniel Acosta-Avalos ◽

Reiner Neumann ◽

Alex S. Silva ◽

...

Keyword(s):

Bottom Sediments ◽

Magnetic Measurements ◽

Culture Media ◽

X Ray Diffraction ◽

X Ray ◽

Ferric Oxyhydroxide ◽

Transmission Electron ◽

Iron Mine ◽

Organic Matter Oxidation ◽

Doce River

On 5 November 2015, a large tailing deposit failed in Brazil, releasing an estimated 32.6 to 62 million m3 of iron mining tailings into the environment. Tailings from the Fundão Dam flowed down through the Gualaxo do Norte and Carmo riverbeds and floodplains and reached the Doce River. Since then, bottom sediments have become enriched in Fe(III) oxyhydroxides. Dissimilatory iron-reducing microorganisms (DIRMs) are anaerobes able to couple organic matter oxidation to Fe(III) reduction, producing CO2 and Fe(II), which can precipitate as magnetite (FeO·Fe2O3) and other Fe(II) minerals. In this work, we investigated the presence of DIRMs in affected and non-affected bottom sediments of the Gualaxo do Norte and Doce Rivers. The increase in Fe(II) concentrations in culture media over time indicated the presence of Fe(III)-reducing microorganisms in all sediments tested, which could reduce Fe(III) from both tailings and amorphous ferric oxyhydroxide. Half of our enrichment cultures converted amorphous Fe(III) oxyhydroxide into magnetite, which was characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. The conversion of solid Fe(III) phases to soluble Fe(II) and/or magnetite is characteristic of DIRM cultures. The presence of DIRMs in the sediments of the Doce River and tributaries points to the possibility of reductive dissolution of goethite (α-FeOOH) and/or hematite (α-Fe2O3) from sediments, along with the consumption of organics, release of trace elements, and impairment of water quality.

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Structural Evolution in Wet Mechanically Alloyed Co-Fe-(Ta,W)-B Alloys

Metals ◽

10.3390/met11050800 ◽

2021 ◽

Vol 11 (5) ◽

pp. 800

Author(s):

Vladimír Girman ◽

Maksym Lisnichuk ◽

Daria Yudina ◽

Miloš Matvija ◽

Pavol Sovák ◽

...

Keyword(s):

Structural Changes ◽

Magnetic Measurements ◽

Structural Evolution ◽

High Energy ◽

Control Agent ◽

X Ray Diffraction ◽

Mechanically Alloyed ◽

X Ray ◽

Transmission Electron ◽

X Ray Absorption

In the present study, the effect of wet mechanical alloying (MA) on the glass-forming ability (GFA) of Co43Fe20X5.5B31.5 (X = Ta, W) alloys was studied. The structural evolution during MA was investigated using high-energy X-ray diffraction, X-ray absorption spectroscopy, high-resolution transmission electron microscopy and magnetic measurements. Pair distribution function and extended X-ray absorption fine structure spectroscopy were used to characterize local atomic structure at various stages of MA. Besides structural changes, the magnetic properties of both compositions were investigated employing a vibrating sample magnetometer and thermomagnetic measurements. It was shown that using hexane as a process control agent during wet MA resulted in the formation of fully amorphous Co-Fe-Ta-B powder material at a shorter milling time (100 h) as compared to dry MA. It has also been shown that substituting Ta with W effectively suppresses GFA. After 100 h of MA of Co-Fe-W-B mixture, a nanocomposite material consisting of amorphous and nanocrystalline bcc-W phase was synthesized.

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Nitroxide radicals appended to phthalonitriles: synthesis, structural characterization and photophysical properties

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229621001832 ◽

2021 ◽

Vol 77 (3) ◽

pp. 137-143

Author(s):

Ismail Fidan ◽

Emel Onal ◽

Catherine Hirel

Keyword(s):

Magnetic Measurements ◽

Photophysical Properties ◽

Nucleophilic Aromatic Substitution ◽

Structural Studies ◽

Aromatic Substitution ◽

Nitronyl Nitroxide ◽

X Ray Diffraction ◽

X Ray ◽

Microwave Assisted ◽

Ft Ir

The syntheses of 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl-2-yl)phenoxy]phthalonitrile (3, C21H19N4O3) and 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-1-oxyl-2-yl)phenoxy]phthalonitrile (4) were carried out by microwave-assisted nucleophilic aromatic substitution of 4-nitrophthalonitrile (2) by the pre-formed 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl (1). Compounds 3 and 4 were characterized unambiguously by a rich array of analyses, such as melting point, FT–IR, MALDI–TOF MS, elemental analysis, UV–Vis, CV, EPR, magnetic measurements and single-crystal X-ray diffraction. Structural studies demonstrate that the C—H...X and C—X...π (X = O and N) interactions in the radical nitronyl nitroxide groups play an important role in the assembly of the crystal structures. Moreover, cyclic voltammetry analyses show that the phthalonitrile substituent retains the redox properties of the Ullman radicals.

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Elaboration of nitride thin films by reactive sputtering

Rem Revista Escola de Minas ◽

10.1590/s0370-44672006000200013 ◽

2006 ◽

Vol 59 (2) ◽

pp. 225-232 ◽

Cited By ~ 1

Author(s):

Pierre Yves Jouan ◽

Arnaud Tricoteaux ◽

Nicolas Horny

Keyword(s):

Thin Films ◽

Compressive Stress ◽

Bias Voltage ◽

Substrate Surface ◽

Lattice Parameter ◽

X Ray Diffraction ◽

X Ray ◽

A Value ◽

Dc Reactive Magnetron Sputtering ◽

Nitrogen Contents

The aim of this paper is first a better understanding of DC reactive magnetron sputtering and its implications, such as the hysteresis effect and the process instability. In a second part, this article is devoted to an example of specific application: Aluminium Nitride. AlN thin films have been deposited by reactive triode sputtering. We have studied the effect of the nitrogen contents in the discharge and the RF bias voltage on the growth of AlN films on Si(100) deposited by triode sputtering. Stoichiometry and crystal orientation of AlN films have been characterized by means of Fourier-transform infrared spectroscopy, X-ray diffraction and secondary electron microscopy. Dense and transparent AlN layers were obtained at high deposition rates. These films have a (002) orientation whatever the nitrogen content in the discharge, but the best crystallised ones are obtained at low value (10%). A linear relationship was observed between the AlN lattice parameter "c" (perpendicular to the substrate surface) and the in-plane compressive stress. Applying an RF bias to the substrate leads to a (100) texture, and films become amorphous. Moreover, the film's compressive stress increases up to a value of 8GPa before decreasing slowly as the bias voltage increases.

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Structure, Magnetic Properties and Hyperfine Parameters of Nd-Substituted Ni-Fe-Ga Heusler Alloys

MRS Advances ◽

10.1557/adv.2017.70 ◽

2017 ◽

Vol 2 (25) ◽

pp. 1341-1346

Author(s):

Monica Sorescu ◽

Felicia Tolea ◽

Mihaela Valeanu ◽

Mihaela Sofronie

Keyword(s):

Melt Spinning ◽

Magnetic Measurements ◽

Heusler Alloys ◽

Hyperfine Magnetic Field ◽

Rapid Quenching ◽

Linear Least Squares ◽

X Ray Diffraction ◽

Hyperfine Parameters ◽

X Ray ◽

Field Distributions

ABSTRACTSamples of Ni57-xNdxFe18Ga25 with x=2 and 4 were prepared in ribbon form by rapid quenching via melt spinning route. The samples were analyzed by X-ray diffraction (XRD), magnetic measurements and Mössbauer spectroscopy, both in the as-quenched form and after thermal annealing at 900 oC for 2 min and 400 °C for 2 hours. For x=2 the Nd atoms are completely dissolved in the Ni-Fe-Ga matrix, while for x=4 the additional occurrence of the secondary 2:17 phase could be resolved. These findings were supported by the analysis of hyperfine magnetic field distributions obtained from the non-linear least-squares fitting of the Mössbauer spectra.

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Influence of Alloying Additions on Enhancement of Soft Magnetic Properties Effect and Crystallization in FeXSiB (X=Cu, V, Co, Zr, Nb) Amorphous Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.130.171 ◽

2007 ◽

Vol 130 ◽

pp. 171-174 ◽

Cited By ~ 3

Author(s):

Z. Stokłosa ◽

G. Badura ◽

P. Kwapuliński ◽

Józef Rasek ◽

G. Haneczok ◽

...

Keyword(s):

Magnetic Properties ◽

Amorphous Alloys ◽

Crystallization Process ◽

Annealing Temperature ◽

Magnetic Measurements ◽

X Ray Diffraction ◽

Soft Magnetic ◽

X Ray ◽

Second Stage ◽

Transmission Electron

The crystallization and optimization of magnetic properties effects in FeXSiB (X=Cu, V, Co, Zr, Nb) amorphous alloys were studied by applying X-ray diffraction methods, high resolution transmission electron microscopy (HRTEM), resistometric and magnetic measurements. The temperatures of the first and the second stage of crystallization, the 1h optimization annealing temperature and the Curie temperature were determined for different amorphous alloys. Activation energies of crystallization process were obtained by applying the Kissinger method. The influence of alloy additions on optimization effect and crystallization processes was carefully examined.

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X-Ray and Magnetic Measurements of TmFeTi2O7

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.215.470 ◽

2014 ◽

Vol 215 ◽

pp. 470-473 ◽

Cited By ~ 4

Author(s):

Tamara V. Drokina ◽

German A. Petrakovskii ◽

Dmitrii A. Velikanov ◽

Maksim S. Molokeev

Keyword(s):

Spin Glass ◽

Solid Phase ◽

Magnetic Measurements ◽

Diffraction Method ◽

Freezing Temperature ◽

Solid Phase Reaction ◽

Phase Reaction ◽

X Ray Diffraction ◽

X Ray ◽

History Of

In this paper we are reported about a peculiarity of the crystal structure and the magnetic state of TmFeTi2O7. The compound TmFeTi2O7 has been synthesizedusing the solid-phase reaction method. Using X-ray diffraction method the disorder in the distribution of the iron ions over five nonequivalent crystal sites was observed, also the populations of the iron atoms positions were determined. We show that below Tf = 6 K the magnetization of TmFeTi2O7 depends on the magnetic history of the sample. There are indications for spin glass state. This results allow us to assume the state of spin glass is realized below freezing temperature Tf = 6 K in TmFeTi2O7.

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Crystal structure of bis{(3,5-dimethylpyrazol-1-yl)dihydro[3-(pyridin-2-yl)pyrazol-1-yl]borato}iron(II)

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989020009214 ◽

2020 ◽

Vol 76 (8) ◽

pp. 1266-1270

Author(s):

Sascha Ossinger ◽

Christian Näther ◽

Felix Tuczek

Keyword(s):

Spin Crossover ◽

Magnetic Measurements ◽

Complex Molecule ◽

High Spin State ◽

Methyl Groups ◽

Asymmetric Unit ◽

Pure Sample ◽

X Ray ◽

Classical Hydrogen Bond

The structure determination of [Fe(C13H15BN5)2] was undertaken as part of a project on the modification of the recently published spin-crossover (SCO) complex [Fe{H2B(pz)(pypz)}2] (pz = pyrazole, pypz = pyridylpyrazole). To this end, a new ligand was synthesized in which two additional methyl groups are present. Its reaction with iron trifluoromethanesulfonate led to a pure sample of the title compound, as proven by X-ray powder diffraction. The asymmetric unit consists of one complex molecule in a general position. The FeII atom is coordinated by two tridentate N-binding {H2B(3,5-(CH3)2-pz)(pypz)}− ligands. The Fe—N bond lengths range between 2.1222 (13) and 2.3255 (15) Å, compatible with FeII in the high-spin state, which was also confirmed by magnetic measurements. Other than a very weak C—H...N non-classical hydrogen bond linking individual molecules into rows extending parallel to [010], there are no remarkable intermolecular interactions.

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Влияние Cr и Ni на формирование фаз в механосинтезированном нанокомпозите на основе Fe-=SUB=-75-=/SUB=-C-=SUB=-25-=/SUB=-

Журнал технической физики ◽

10.21883/jtf.2020.05.49180.154-18 ◽

2020 ◽

Vol 90 (5) ◽

pp. 787

Author(s):

А.А. Чулкина ◽

А.И. Ульянов ◽

В.А. Волков ◽

А.Л. Ульянов ◽

А.В. Загайнов

Keyword(s):

Curie Temperature ◽

Amorphous Phase ◽

Annealing Temperature ◽

Magnetic Measurements ◽

Nickel Content ◽

X Ray Diffraction ◽

Mechanical Synthesis ◽

X Ray ◽

Higher Temperature ◽

Two Phases

X-ray diffraction, Mossbauer spectroscopy, and magnetic measurements have been used to study the phase formation and doping during mechanical synthesis (MS) and subsequent annealing of the alloy (Fe0.80Cr0.05Ni0.15)75C25. It has been shown that, after MS, the nanocomposite contains mainly two phases – an amorphous phase and cementite A. During annealing, as a result of crystallization of the amorphous phase, cementite B is formed, in which contains more nickel than in the mechanically synthesized cementite A. As the annealing temperature increases, austenite, which is inhomogeneous in nickel content, is formed. The Curie temperature of this austenite reaches 500 °C. It has been determined that cementite in the mechanosynthesized nanocomposite (Fe,Cr,Ni)75C25 has a higher temperature stabilitythan that in a MS composite (Fe,Ni)75C25.

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