scholarly journals Synthesized and characterization nanosized synthesis Fe3O4powder from natural iron sand

2021 ◽  
Vol 1943 (1) ◽  
pp. 012013
Author(s):  
A N Syahida ◽  
H Sutanto ◽  
I Alkian ◽  
F D D Irianti ◽  
A A Wibowo ◽  
...  
Keyword(s):  
Natural Iron

Transformation of Structure, Magnetic Properties and Microwave Absorption Capability in Nd-Doped Strontium Hexaferrite

2020 ◽  
Vol 855 ◽  
pp. 255-260
Author(s):  
Mukhtar Effendi ◽  
Efi Solihah ◽  
Candra Kurniawan ◽  
Wahyu Tri Cahyanto ◽  
Wahyu Widanarto
Keyword(s):  
Magnetic Properties ◽  
Microwave Absorption ◽  
Solid State Reaction Method ◽  
Strontium Hexaferrite ◽  
Basic Material ◽  
X Ray Diffraction ◽  
Cell Parameters ◽  
Tetragonal Crystal ◽  
Capability Analysis ◽  
Natural Iron

The synthesize of Nd3+-strontium hexaferrite magnetic material by the solid-state reaction method has been successfully carried out. This study aims to determine the effect of Nd3+ on the structure, magnetic properties, and microwave absorption capability of the material. Preparation of (1-x)SrO:xNd2O3:6Fe2O3 where x = 0, 10, 20, and 30 mol% using basic material in the form of SrCO3 powder, Nd2O3 powder and Fe3O4 from natural iron sand. The characterization includes the X-Ray Diffraction (XRD) examination to determine the crystal structure, the Scanning Electron Microscope (SEM) for exploring the surface morphology, Vibrating Sample Magnetometer (VSM) for the magnetic properties investigation of material, and Vector Network Analyzer (VNA) for microwave absorption capability analysis. The XRD results show that the addition of Nd3+ doping increases the number of SrNdFeO4 phases. The phase has a tetragonal crystal system that has cell parameters a = b = 3.846 Å, and c = 12.594 Å. The magnetic properties of the material showed that the addition of Nd3+ decreased the saturation and remanence magnetization values, whereas the value of the coercivity field increased. Meanwhile, the best microwave absorption occurs in samples with the addition of Nd3+ as much as 0.3 mol, which results in a reflection loss value of -18.9 dB with a frequency bandwidth of 3.9 GHz.

scholarly journals Characterization and Reconstitution of Human Lipoyl Synthase (LIAS) Supports ISCA2 and ISCU as Primary Cluster Donors and an Ordered Mechanism of Cluster Assembly

2021 ◽  
Vol 22 (4) ◽  
pp. 1598
Author(s):  
Amber L. Hendricks ◽  
Christine Wachnowsky ◽  
Brian Fries ◽  
Insiya Fidai ◽  
James A. Cowan
Keyword(s):  
Cluster Assembly ◽  
Paramagnetic Resonance ◽  
Iron Sulfur Cluster ◽  
Sulfur Transfer ◽  
Disease States ◽  
Isolation And Characterization ◽  
Iron Sulfur ◽  
Natural Iron ◽  
Lipoyl Synthase

Lipoyl synthase (LIAS) is an iron–sulfur cluster protein and a member of the radical S-adenosylmethionine (SAM) superfamily that catalyzes the final step of lipoic acid biosynthesis. The enzyme contains two [4Fe–4S] centers (reducing and auxiliary clusters) that promote radical formation and sulfur transfer, respectively. Most information concerning LIAS and its mechanism has been determined from prokaryotic enzymes. Herein, we detail the expression, isolation, and characterization of human LIAS, its reactivity, and evaluation of natural iron–sulfur (Fe–S) cluster reconstitution mechanisms. Cluster donation by a number of possible cluster donor proteins and heterodimeric complexes has been evaluated. [2Fe–2S]-cluster-bound forms of human ISCU and ISCA2 were found capable of reconstituting human LIAS, such that complete product turnover was enabled for LIAS, as monitored via a liquid chromatography–mass spectrometry (LC–MS) assay. Electron paramagnetic resonance (EPR) studies of native LIAS and substituted derivatives that lacked the ability to bind one or the other of LIAS’s two [4Fe–4S] clusters revealed a likely order of cluster addition, with the auxiliary cluster preceding the reducing [4Fe–4S] center. These results detail the trafficking of Fe–S clusters in human cells and highlight differences with respect to bacterial LIAS analogs. Likely in vivo Fe–S cluster donors to LIAS are identified, with possible connections to human disease states, and a mechanistic ordering of [4Fe–4S] cluster reconstitution is evident.

Elemental composition of deposits on natural iron oxide catalyst in processing medium-sulfur feed

1995 ◽  
Vol 31 (6) ◽  
pp. 288-292 ◽  
Author(s):  
�. G. Telyashev ◽  
R. R. Vezirov ◽  
I. R. Yavgil'din ◽  
I. O. Tuktarova ◽  
G. G. Telyashev ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Elemental Composition ◽  
Oxide Catalyst ◽  
Iron Oxide Catalyst ◽  
Natural Iron

Effects of metal cations on the fulvic acid (FA) adsorption onto natural iron oxide in iron ore pelletizing process

2016 ◽  
Vol 302 ◽  
pp. 90-99 ◽  
Author(s):  
Youlian Zhou ◽  
Yuanbo Zhang ◽  
Guanghui Li ◽  
Tao Jiang
Keyword(s):  
Iron Oxide ◽  
Fulvic Acid ◽  
Iron Ore ◽  
Metal Cations ◽  
Natural Iron

The influence of thermal treatment on bioweathering and arsenic sorption capacity of a natural iron (oxyhydr)oxide-based adsorbent

Chemosphere ◽  
2017 ◽  
Vol 188 ◽  
pp. 99-109 ◽  
Author(s):  
Klaudia Debiec ◽  
Grzegorz Rzepa ◽  
Tomasz Bajda ◽  
Lukasz Zych ◽  
Jan Krzysztoforski ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Sorption Capacity ◽  
Natural Iron

scholarly journals Imprint of a dissolved cobalt basaltic source on the Kerguelen Plateau

2012 ◽  
Vol 9 (12) ◽  
pp. 5279-5290 ◽  
Author(s):  
J. Bown ◽  
M. Boye ◽  
P. Laan ◽  
A. R. Bowie ◽  
Y.-H. Park ◽  
...  
Keyword(s):  
Surface Waters ◽  
External Input ◽  
Eastern Slope ◽  
Kerguelen Plateau ◽  
Dissolved Iron ◽  
Deep Waters ◽  
Iron Supply ◽  
Natural Iron ◽  
Shelf Sediments ◽  
Lateral Advection

Abstract. Processes of cobalt (Co) entrainment from shelf sediments over the Kerguelen Plateau were studied during the KEOPS (Kerguelen Ocean Plateau compared Study) in order to explain the exceptionally high dissolved cobalt concentrations that have been measured in the surface waters above the Kerguelen Plateau, and in intermediate and deep waters above its eastern slope. Lateral advection and dissolution of Co contained in basalt sediments around Heard Island, a main source of lithogenic Co in the study area, were shown to imprint the process of surface enrichment over the plateau. Dissolved Co enrichment was strongest at the intercept of the eastern slope with intermediate and deep waters, probably due to more efficient mobilisation of the sediments in the slope current, in addition to advection of Co-enriched and low-oxygenated ocean water masses. In surface waters, the strong sedimentary Co inputs were estimated to be much higher than biological Co uptake in phytoplankton blooms, underlining the potential use of dissolved cobalt as tracer of the natural iron fertilization above the Kerguelen Plateau. Based on a simple steady-state balance equation of the external input of dissolved iron over the plateau, the fertilization of iron inferred by using dissolved Co as a tracer of basalt sources is estimated to be 28 × 102 ± 21 × 102 t yr−1 in surface waters of the Kerguelen Plateau. This estimate is consistent with preceding ones (Zhang et al., 2008; Chever et al., 2010), and the calculated iron supply matches with the phytoplankton demand (Sarthou et al., 2008).

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