scholarly journals Engineering Pyrite-Type Bimetallic Ni-Doped CoS2 Nanoneedle Arrays over a Wide Compositional Range for Enhanced Oxygen and Hydrogen Electrocatalysis with Flexible Property

Catalysts ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 366 ◽  
Author(s):  
Guowei He ◽  
Wei Zhang ◽  
Yida Deng ◽  
Cheng Zhong ◽  
Wenbin Hu ◽  
...  
Keyword(s):  
Compositional Range ◽  
Wide Compositional Range

Thermoelectric Properties of Ru2Si3-Based Chimney-Ladder Phases

2007 ◽  
Vol 561-565 ◽  
pp. 463-466 ◽  
Author(s):  
Kyosuke Kishida ◽  
Akira Ishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structures ◽  
Thermoelectric Properties ◽  
Electron Concentration ◽  
Valence Electron ◽  
Valence Electron Concentration ◽  
Compositional Range ◽  
Wide Compositional Range ◽  
P Type ◽  
Semiconducting Behavior

The variations of the crystal structures and thermoelectric properties of the Ru1-xRexSiy chimney-ladder phases were studied as a function of the Re concentration. A series of chimney-ladder phases with a compositional formula of Ru1-xRexSi1.539+0.178x are formed in a wide compositional range, 0.14 ≤ x ≤ 0.76. The composition of the chimney-ladder phase is systematically deviated from the idealized composition satisfying the valence electron concentration rule: VEC=14. Measurements of thermoelectric properties reveal that the chimney-ladder phases exhibit n-type semiconducting behavior at low Re concentrations and p-type semiconducting behavior at high Re concentrations, which are well consistent with the prediction based on the deviation of the composition of the chimney-ladder phase from the idealized composition.

Crystal Structure and Thermoelectric Properties of Mn-Substituted Ru2Si3 with the Chimney-Ladder Structure

2008 ◽  
Vol 1128 ◽  
Author(s):  
Tatsuya Koyama ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Thermoelectric Properties ◽  
Solid Solubility ◽  
Solubility Limit ◽  
Ladder Structure ◽  
Thermoelectric Power Factor ◽  
Compositional Range ◽  
General Chemical ◽  
Ternary Element ◽  
Wide Compositional Range ◽  
Mn Content

AbstractChimney-ladder compounds with the general chemical formula of Mn X2n-m (n, m: integers) possess tetragonal crystal structures which consist of two types of subcells; one composed of transition metal atoms (M) with the γÀ-Sn structure and the other composed of group 13 or 14 atoms (X) with a helical arrangement along the tetragonal c-axis. Since the chimney-ladder compounds generally exhibit very low thermal conductivity, presumably due to its long periodicity along the c-axis, they have been extensively investigated as promising thermoelectric materials. The high-temperature (HT) phase of Ru2Si3 is one of the chimney-ladder compounds with n=2 and m=1. Recently we have found that the HT-Ru2Si3 phase is stabilized by substituting Ru with Re so as to exist even at low temperatures in a wide compositional range of the Re content (Re: 14 to 73%), and that the thermoelectric power factor for alloys with high Re contents increases with the Re content and the highest value was obtained for the alloy with the highest Re content (73%), which is the solubility limit of Re in the chimney-ladder phase. In order to further enhance the thermoelectric properties, another ternary element which extends the solid solubility region of the HT-Ru2Si3 phase is favorable. We have chosen Mn as the ternary element because Mn4Si7 with the chimney-ladder structure exists as a counterpart of HT-Ru2Si3 in the Ru2Si3 -Mn4Si7 pseudo-binary system so that the solid solubility region of the chimney-ladder phase is anticipated to extend in a wider composition range than the Re case. Our study, in fact, shows that the Mn-substitution stabilizes the HT-Ru2Si3 phase in a wide compositional range of the Mn content; 12 to 100%. Compositional analyses indicate that the Si/M ratio gradually increases as the Mn content increases. This is considered to be due to the addition of Si atoms in the Si subcell in order to compensate the decrease in the valence electron concentrations (VEC) per M atom by the substitution of Ru (group 8) with Mn (group 7) with fewer valence electrons. The Seebeck coefficient and electrical resistivity of the Mn-substituted Ru2Si3 are explained in terms of the VEC deviation from the idealized value, 14, which is expected for intrinsic semiconductors with the chimney-ladder structure. The highest dimensionless thermoelectric figure of merit (ZT=0.76) is obtained for 90%Mn-substituted alloy. The relationships between the microstructure and thermoelectric properties will be discussed.

scholarly journals Brønsted acids in ionic liquids: how acidity depends on the liquid structure

2014 ◽  
Vol 16 (42) ◽  
pp. 23233-23243 ◽  
Author(s):  
Jade A. McCune ◽  
Peizhao He ◽  
Marina Petkovic ◽  
Fergal Coleman ◽  
Julien Estager ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Structure ◽  
Liquid Mixtures ◽  
Bronsted Acids ◽  
Bronsted Acid ◽  
Acceptor Number ◽  
Compositional Range ◽  
Brönsted Acid ◽  
Wide Compositional Range

Gutmann Acceptor Number (AN) values have been determined for Brønsted acid–ionic liquid mixtures, over a wide compositional range.

Stoichiometric icosahedral phase in the Zn–Mg–Y system

1997 ◽  
Vol 12 (6) ◽  
pp. 1468-1471 ◽  
Author(s):  
A. P. Tsai ◽  
A. Niikura ◽  
A. Inoue ◽  
T. Masumoto
Keyword(s):  
Formation Process ◽  
Peritectic Reaction ◽  
Stoichiometric Composition ◽  
Icosahedral Phase ◽  
Peritectic Temperature ◽  
Constant Composition ◽  
Compositional Range ◽  
Wide Compositional Range

Stoichiometric composition and formation process of the icosahedral phase in the Zn–Mg–Y system have been studied. The icosahedral phase exhibit a stoichiometric composition in the vicinity of Zn60Mg30Y10. During cooling, (Zn, Mg)5Y phase primarily crystallizes from the melt at ∼960 K and then undergoes a peritectic reaction with the residual Mg-enriched melt (∼820 K) to form the icosahedral phase. The melt with a constant composition close to Mg7Zn3 is in equilibrium with the (Zn, Mg)5Y phase above the peritectic temperature in a wide compositional range.

scholarly journals The Petrology and  Genesis of Silicic  Magmas in the  Kermadec Arc

2021 ◽  
Author(s):  
◽  
Simon James Barker
Keyword(s):  
Subduction Zone ◽  
Structural Changes ◽  
Mineral Chemistry ◽  
Silicic Magma ◽  
Small Scale ◽  
Mafic Enclaves ◽  
Compositional Range ◽  
Dominant Process ◽  
Wide Compositional Range ◽  
Silicic Magmas

<p>Recent work has shown that silicic volcanism can be abundant in intra-oceanic subduction settings, and is often associated with large explosive caldera-forming eruptions. Several major petrogenetic questions arise over the origin and eruption of large amounts of silicic magma at these relatively simple subduction settings. This study has investigated the geochemistry of pyroclasts collected from four volcanoes along the Kermadec arc, a young (<2 Myr) oceanic subduction zone in the southwest Pacific. Raoul, Macauley and a newly discovered volcano (here informally named 'New volcano') in the northern Kermadec arc, and Healy volcano in the southern Kermadec arc have all erupted dacitic to rhyolitic pumice within the last 10 kyr. For Raoul, New volcano and Healy, whole rock major element compositions fall with a limited compositional range. In contrast, pumice dredged from around Macauley caldera covers a wide compositional range indicating that there have been multiple silicic eruptions, not just the Sandy Bay Tephra exposed on Macauley Island. Distinctive crystal populations in both pumice samples and plutonic xenoliths suggest that many of the crystals did not grow in the evolved magmas, but were mixed in from other sources including gabbros and tonalites. Such open system mixing is ubiquitous in magmas from the four Kermadec volcanoes studied here. Silicic magmas, co-eruptive mafic enclaves and previously erupted basalts show sub-parallel REE patterns, and crystal composition and zonation suggests that mafic and silicic magmas have a strong genetic affiliation. Examination of whole rock, glass and mineral chemistry reveals that evolved magmas can be generated at each volcano through 60-75% crystal fractionation of a basaltic parent. These findings are not consistent with silicic magma generation via crustal anatexis, as previously suggested for the Kermadec arc. Although crystallisation is the dominant process driving melt evolution in the Kermadec volcanoes, the magmatic systems are open to contributions from both newly arriving melts and wholly crystalline plutonic bodies. Such processes occur in variable proportions between magma batches, and are largely reflected by small scale chemical variations between eruption units. Larger scale chemical trends reflect the position of the volcanoes along the arc, which in turn may reflect structural changes in the subduction zone and variations in sediment influx.</p>

scholarly journals The Petrology and  Genesis of Silicic  Magmas in the  Kermadec Arc

2021 ◽  
Author(s):  
◽  
Simon James Barker
Keyword(s):  
Subduction Zone ◽  
Structural Changes ◽  
Mineral Chemistry ◽  
Silicic Magma ◽  
Small Scale ◽  
Mafic Enclaves ◽  
Compositional Range ◽  
Dominant Process ◽  
Wide Compositional Range ◽  
Silicic Magmas

<p>Recent work has shown that silicic volcanism can be abundant in intra-oceanic subduction settings, and is often associated with large explosive caldera-forming eruptions. Several major petrogenetic questions arise over the origin and eruption of large amounts of silicic magma at these relatively simple subduction settings. This study has investigated the geochemistry of pyroclasts collected from four volcanoes along the Kermadec arc, a young (<2 Myr) oceanic subduction zone in the southwest Pacific. Raoul, Macauley and a newly discovered volcano (here informally named 'New volcano') in the northern Kermadec arc, and Healy volcano in the southern Kermadec arc have all erupted dacitic to rhyolitic pumice within the last 10 kyr. For Raoul, New volcano and Healy, whole rock major element compositions fall with a limited compositional range. In contrast, pumice dredged from around Macauley caldera covers a wide compositional range indicating that there have been multiple silicic eruptions, not just the Sandy Bay Tephra exposed on Macauley Island. Distinctive crystal populations in both pumice samples and plutonic xenoliths suggest that many of the crystals did not grow in the evolved magmas, but were mixed in from other sources including gabbros and tonalites. Such open system mixing is ubiquitous in magmas from the four Kermadec volcanoes studied here. Silicic magmas, co-eruptive mafic enclaves and previously erupted basalts show sub-parallel REE patterns, and crystal composition and zonation suggests that mafic and silicic magmas have a strong genetic affiliation. Examination of whole rock, glass and mineral chemistry reveals that evolved magmas can be generated at each volcano through 60-75% crystal fractionation of a basaltic parent. These findings are not consistent with silicic magma generation via crustal anatexis, as previously suggested for the Kermadec arc. Although crystallisation is the dominant process driving melt evolution in the Kermadec volcanoes, the magmatic systems are open to contributions from both newly arriving melts and wholly crystalline plutonic bodies. Such processes occur in variable proportions between magma batches, and are largely reflected by small scale chemical variations between eruption units. Larger scale chemical trends reflect the position of the volcanoes along the arc, which in turn may reflect structural changes in the subduction zone and variations in sediment influx.</p>

scholarly journals Electronic properties of phases in the quasi-binary Bi2Se3-Bi2S3 system.

2021 ◽  
Author(s):  
Zipporah Rini Benher ◽  
Sandra Gardonio ◽  
Mattia Fanetti ◽  
Paolo Moras ◽  
Asish Kumar Kundu ◽  
...  
Keyword(s):  
Solid Solution ◽  
Diffraction Analysis ◽  
Electronic Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compositional Range ◽  
System P ◽  
Wide Compositional Range

We explored the properties of the quasi-binary Bi2Se3-Bi2S3 system over a wide compositional range. X-ray diffraction analysis demonstrates that rhombohedral crystals can be synthesized within the solid solution interval 0-22...

Optimization of a Leaching Tank for Hydrometallurgical Recovery of Metals

2009 ◽  
Author(s):  
M. C. L. G. Vilarinho ◽  
N. M. B. Gonc¸alves ◽  
J. C. F. Teixeira
Keyword(s):  
Laboratory Tests ◽  
Metal Extraction ◽  
Cfd Model ◽  
High Concentration ◽  
Metal Plating ◽  
Metals Recovery ◽  
High Metal ◽  
Leaching Solution ◽  
Wide Compositional Range ◽  
Overall Efficiency

The sludge wastes generated by the metal plating industries are classified as hazardous wastes because of their high concentration of heavy metals. Amongst the various routes for their treatment, the hydrometallurgical processes are highly attractive because they can be tailored to the wide compositional range of such wastes and assure its metals recovery and/or toxicity reduction. In these processes the leaching operation is paramount to the overall efficiency. In this, the mixing of the leaching solution with sludge has to be effective in order to obtain high levels of metal extraction and make the process attractive. Most of the available data refers to laboratory tests. This paper reports on the use of CFD model to optimize the operation of a pilot size leaching tank. The results regarding the velocity field were compared with experimental data and proved that such techniques can be effectively applied to improve the process. A leaching experiment, with the best configuration for the mixing, yielded a high metal extraction, suggesting that this technique can be successfully implemented for the treatment of such wastes.

Structural Evolution of Li[sub 3+x]Fe(MoO[sub 4])[sub 3] upon Lithium Insertion in the Compositional Range 0≤x≤1

2006 ◽  
Vol 153 (2) ◽  
pp. A275 ◽  
Author(s):  
M. E. Arroyo y de Dompablo ◽  
M. Alvarez-Vega ◽  
C. Baehtz ◽  
U. Amador
Keyword(s):  
Structural Evolution ◽  
Lithium Insertion ◽  
Compositional Range

scholarly journals A structure hierarchy for silicate minerals: chain, ribbon, and tube silicates

2020 ◽  
Vol 84 (2) ◽  
pp. 165-244 ◽  
Author(s):  
Maxwell C. Day ◽  
Frank C. Hawthorne
Keyword(s):  
Repeat Unit ◽  
Structural Connectivity ◽  
The Other ◽  
Silicate Minerals ◽  
One Dimensional ◽  
Compositional Range ◽  
Repeat Units ◽  
Sheet Silicates ◽  
Sheet Silicate ◽  
Connectivity Degree

AbstractA structure hierarchy is developed for chain-, ribbon- and tube-silicate based on the connectedness of one-dimensional polymerisations of (TO4)n− tetrahedra, where T = Si4+ plus P5+, V5+, As5+, Al3+, Fe3+, B3+, Be2+, Zn2+ and Mg2+. Such polymerisations are described by a geometrical repeat unit (with ng tetrahedra) and a topological repeat unit (or graph) (with nt vertices). The connectivity of the tetrahedra (vertices) in the geometrical (topological) repeat units is denoted by the expression cTr (cVr) where c is the connectivity (degree) of the tetrahedron (vertex) and r is the number of tetrahedra (vertices) of connectivity (degree) c in the repeat unit. Thus cTr = 1Tr12Tr23Tr34Tr4 (cVr = 1Vr12Vr23Vr34Vr4) represents all possible connectivities (degrees) of tetrahedra (vertices) in the geometrical (topological) repeat units of such one-dimensional polymerisations. We may generate all possible cTr (cVr) expressions for chains (graphs) with tetrahedron (vertex) connectivities (degrees) c = 1 to 4 where r = 1 to n by sequentially increasing the values of c and r, and by ranking them accordingly. The silicate (sensu lato) units of chain-, ribbon- and tube-silicate minerals are identified and associated with the relevant cTr (cVr) symbols. Following description and association with the relevant cTr (cVr) symbols of the silicate units in all chain-, ribbon- and tube-silicate minerals, the minerals are arranged into decreasing O:T ratio from 3.0 to 2.5, an arrangement that reflects their increasing structural connectivity. Considering only the silicate component, the compositional range of the chain-, ribbon- and tube-silicate minerals strongly overlaps that of the sheet-silicate minerals. Of the chain-, ribbon- and tube-silicates and sheet silicates with the same O:T ratio, some have the same cVr symbols (vertex connectivities) but the tetrahedra link to each other in different ways and are topologically different. The abundance of chain-, ribbon- and tube-silicate minerals decreases as O:T decreases from 3.0 to 2.5 whereas the abundance of sheet-silicate minerals increases from O:T = 3.0 to 2.5 and decreases again to O:T = 2.0. Some of the chain-, ribbon- and tube-silicate minerals have more than one distinct silicate unit: (1) vinogradovite, revdite, lintisite (punkaruaivite) and charoite have mixed chains, ribbons and/or tubes; (2) veblenite, yuksporite, miserite and okenite have clusters or sheets in addition to chains, ribbons and tubes. It is apparent that some chain-ribbon-tube topologies are favoured over others as of the ~450 inosilicate minerals, ~375 correspond to only four topologically unique graphs, the other ~75 minerals correspond to ~46 topologically unique graphs.

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