Effect of calcium on natural iron rich geo-polymeric binder

Author(s):  
C.S. Belarmin Xavier ◽  
Abdul Rahim ◽  
Jessin John ◽  
Nithin Suresh Kumar
2020 ◽  
Vol 855 ◽  
pp. 255-260
Author(s):  
Mukhtar Effendi ◽  
Efi Solihah ◽  
Candra Kurniawan ◽  
Wahyu Tri Cahyanto ◽  
Wahyu Widanarto

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.


2021 ◽  
Vol 22 (4) ◽  
pp. 1598
Author(s):  
Amber L. Hendricks ◽  
Christine Wachnowsky ◽  
Brian Fries ◽  
Insiya Fidai ◽  
James A. Cowan

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.


RSC Advances ◽  
2019 ◽  
Vol 9 (51) ◽  
pp. 29765-29771 ◽  
Author(s):  
Minghui Xu ◽  
Xianming Lu ◽  
Hongchang Mo ◽  
Ning Liu ◽  
Qian Zhang ◽  
...  

A novel energetic polymeric binder PBFMO-b-PNMMO alternative block thermoplastic elastomer was developed for metal-rich solid propellants.


1995 ◽  
Vol 31 (6) ◽  
pp. 288-292 ◽  
Author(s):  
�. G. Telyashev ◽  
R. R. Vezirov ◽  
I. R. Yavgil'din ◽  
I. O. Tuktarova ◽  
G. G. Telyashev ◽  
...  

2017 ◽  
Vol 789 ◽  
pp. 012033
Author(s):  
I S Miftakhov ◽  
A V Trofimov ◽  
A I Nagmutdinova ◽  
E F Voznesensky ◽  
F S Sharifullin ◽  
...  

2016 ◽  
Vol 302 ◽  
pp. 90-99 ◽  
Author(s):  
Youlian Zhou ◽  
Yuanbo Zhang ◽  
Guanghui Li ◽  
Tao Jiang

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