scholarly journals GRANITOID MASSIVES OF THE TRANSITION ZONE OF OXIDATION-REDUCTION CONDITIONS (SIKHOTE-ALIN OROGENIC BELT)

2021 ◽  
Vol 24 (2-3) ◽  
pp. 60-63
Author(s):  
E.A. Konovalova ◽  
L.F. Mishin ◽  
Yu.V. Taltykin
Keyword(s):  
Magnetic Susceptibility ◽  
Mineral Composition ◽  
Igneous Rocks ◽  
Redox Conditions ◽  
Magnetic Fraction ◽  
Sikhote Alin ◽  
Detailed Data ◽  
Variable Valence ◽  
Oxidation Reduction ◽  
First Time

Redox conditions for the formation of igneous rocks determine the valence of variable valence elements. The ore mineral composition and amount, the magnetic fraction weight and the magnetic susceptibility of the rock and the composition of the dark-colored minerals depend on the ratio of Fe3+ and Fe2+. It is for the first time for more than 50 years of the redox conditions study that the he authors obtained detailed data on granitoid massifs located in the zone of redox conditions transition.

scholarly journals REDOX ZONALITY OF THE SIKHOTE-ALIN ORGANIC BELT, CONNECTION WITH GEODYNAMICS

2021 ◽  
Vol 24 (2-3) ◽  
pp. 81-84
Author(s):  
Yu.V. Taltykin ◽  
L.F. Mishin ◽  
E.A. Konovalova
Keyword(s):  
Orogenic Belt ◽  
Igneous Rocks ◽  
Redox Conditions ◽  
Magmatic Activity ◽  
Sikhote Alin

The study of the redox conditions of crystallization of igneous rocks zoning in the Sikhote-Alin orogenic belt has allowed the authors to make a conclusion: there is a redox background in the lithosphere of the region where all magmatic activity occurs. The background does no. depend on the age and petrographic features of igneous rocks. It depends on the position of oceanic and continental plates in convergent zones.

scholarly journals Окислительно-восстановительный фон в земной коре Сихотэ-Алиньского орогенного пояса при кристаллизации магматитов мел-палеогенового возраста: связь с геодинамикой

2020 ◽  
pp. 24-38
Author(s):  
Yu. V. Taltykin ◽  
◽  
L. F. Mishin ◽  
E. A. Konovalova ◽  
◽  
...  
Keyword(s):  
Orogenic Belt ◽  
Redox Conditions ◽  
Western Pacific ◽  
Sikhote Alin ◽  
Mechanism Of Formation ◽  
Magma Crystallization ◽  
The Relationship

A new mechanism for the formation of ilmenite and magnetite series of granitoids in the Sikhote-Alin orogenic belt is proposed. The existing distribution zones of these magmatites are associated with the regional redox background, where magma crystallization occurs. The paper shows the relationship between the redox background in the lithosphere of the region and subduction processes in the Cretaceous-Paleogene time. The proposed mechanism of formation of the ilmenite and magnetite zones of Sikhote-Alin also explains the differences in redox conditions during the crystallization of Mesozoic magmatites in the orogens of the Eastern and Western Pacific coasts.

scholarly journals Review of the congrid eel genus Conger (Anguilliformes: Congridae) in Taiwan

Zootaxa ◽  
2018 ◽  
Vol 4454 (1) ◽  
pp. 168 ◽  
Author(s):  
DAVID G. SMITH ◽  
HSUAN-CHING HO
Keyword(s):  
Mature Male ◽  
Detailed Data ◽  
Key To Species ◽  
Male Specimen ◽  
Diagnostic Characters ◽  
Conger Myriaster ◽  
First Time

The congrid eel genus Conger in Taiwan is reviewed. Five species are recognized, including C. jordani, C. cinereus, C. macrocephalus, C. myriaster and a newly collected species, C. philippinus. A mature male specimen of Conger myriaster is described for the first time. Specimens previously identified as C. japonicus (= C. myriaster) were misidentifications of above mentioned species. The diagnostic characters are discussed. Detailed data on all five species and a key to species in Taiwan are provided.

Correlation between the mineral composition and strength properties of sulfate rocks

2021 ◽  
pp. qjegh2020-173
Author(s):  
Mohammad Reza Rahimi ◽  
Seyed Davoud Mohammadi ◽  
Alireza Taleb Beydokhti
Keyword(s):  
Mineral Composition ◽  
Failure Mode ◽  
Strength Properties ◽  
Shear Mode ◽  
Rock Cores ◽  
Strength Tests ◽  
Engineering Problems ◽  
Gypsum Rock ◽  
Under Construction ◽  
First Time

The literature review confirms that the effect of mineral composition on the strength properties of rocks has rarely been studied. One of the most problematic sedimentary rocks is sulfate rocks, which cause engineering problems in the infrastructure sites such as reservoir dams. In this paper, for the first time, the effect of mineral composition on the strength properties of sulfate rocks was investigated. The rock blocks were collected from the Gachsaran Formation outcrops at the four under construction reservoir dam sits in Iran. After preparing, drying and saturation the rock cores samples (329 samples), uniaxial compressive strength tests were performed in accordance with ASTM and ISRM standards. The results of this study confirmed that firstly, there is a correlation between the mineral composition and the strength properties of the sulfate rocks, but the obtained relationships do not have the necessary certainty to be used as predictive equations. Secondly, by increasing the amount of anhydrite or microcrystalline carbonates in a gypsum rock, its strength properties are increased. Thirdly, in a dry condition the dominant failure mode in gypsum and anhydrite rocks is a shear and dilatation mode, respectively, but after saturation, the failure mode tends to shear mode.

scholarly journals Kinetics studies and mechanism evolution of the epoxidation of styrene over nanoporous Au doped TS-1

2010 ◽  
Vol 12 (4) ◽  
pp. 72-78 ◽  
Author(s):  
Samidha Saxena ◽  
Reena Dwivedi ◽  
Sheenu Bhadauria ◽  
V. Chumbhale ◽  
Rajendra Prasad
Keyword(s):  
Hydrogen Peroxide ◽  
Batch Reactor ◽  
Styrene Oxide ◽  
Reduction Process ◽  
Kinetics Studies ◽  
Oxidation Reduction ◽  
Slurry Phase ◽  
Rate Of Reaction ◽  
First Time ◽  
Mechanism Of The Reaction

Kinetics studies and mechanism evolution of the epoxidation of styrene over nanoporous Au doped TS-1 A kinetic investigation of the slurry phase epoxidation of styrene with hydrogen peroxide has been carried out, for the first time, over nanoporous Au doped TS-1 catalyst, in a batch reactor, in the temperature range of 313-333 K. It was found that product selectivity and the rate of reaction are greatly influenced by concentrations of styrene and hydrogen peroxide. Kinetics studies reveal that the mechanism of the reaction is of the "Redox" type. The rate equation, r = k1 k2 PO PH / (k1 PO + k2 PH) deduced, assuming a steady state involving two stage oxidation-reduction process, represent the data most satisfactorily for the conversion of styrene to styrene oxide. A tentative mechanism of the process has also been suggested.

scholarly journals Carbasugar analogues of galactofuranosides: α-O-linked derivatives

2010 ◽  
Vol 6 ◽  
pp. 1127-1131 ◽  
Author(s):  
Jens Frigell ◽  
Ian Cumpstey
Keyword(s):  
Ring Opening ◽  
Indirect Method ◽  
Reduction Sequence ◽  
Oxidation Reduction ◽  
Acidic Conditions ◽  
First Time

Using an indirect method, we have synthesised α-linked carbasugar analogues of galactofuranosides for the first time. Ring opening of a β-talo configured carbasugar 1,2-epoxide by alcohol nucleophiles under Lewis acidic conditions proceeded with very good regioselectivity to give α-talo configured C1-substituted ethers with a free OH-group at the C2 position. Inversion of configuration at C2 by an oxidation–reduction sequence gave the α-galacto configured carbahexofuranose C1 ethers. A carbadisaccharide corresponding to the Galf(α1→3)Manp substructure from Apodus deciduus galactomannan was synthesised to exemplify the method.

scholarly journals Quantification of pedogenic particles masked by geogenic magnetic fraction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcin Szuszkiewicz ◽  
Hana Grison ◽  
Eduard Petrovský ◽  
Maria Magdalena Szuszkiewicz ◽  
Beata Gołuchowska ◽  
...  
Keyword(s):  
Environmental Magnetism ◽  
Igneous Rocks ◽  
Coarse Grained ◽  
Masking Effect ◽  
Magnetic Contribution ◽  
Magnetic Fraction ◽  
Magnetic Signal ◽  
Magnetic Parameters ◽  
Fine Grained ◽  
Natural Substances

AbstractPedogenic magnetic fraction in soils is attributed to fine-grained particles, i.e. superparamagnetic grains. In the case of a strongly magnetic geogenic fraction, pedogenic magnetic contribution is hard to detect. To the best of our knowledge, detailed research into the masking of pedogenic superparamagnetic grains and quantification of this effect has not yet been carried out. The principal aim of our research is to quantify the influence of coarse-grained ferrimagnetic fraction on the detection of the superparamagnetic grains. In order to describe the masking phenomenon, volume and frequency-dependent magnetic susceptibility were determined on a set of laboratory prepared samples composed of natural substances: a diamagnetic quartz matrix, detrital coarse-grained ferrimagnetic crystals from alkaline and ultra-alkaline igneous rocks, and superparamagnetic soil concretions formed in the Haplic Cambisol. Mineralogy, concentration, type and grain size of the tested material were described by parameters of environmental magnetism. The magnetic parameters distinguish both geogenic multidomain and pedogenic superparamagnetic grains. The magnetic signal of the superparamagnetic grains is gradually masked by the increasing proportion of multidomain grains of magnetite/maghemite. The experiment clearly describes the masking effect and brings new insight to studies dealing with strongly magnetic soils of natural and/or highly contaminated origin as a tool for estimation of superparamagnetic pedogenic contribution.

Rare-earth-doped α′-Sialon ceramics with novel optical properties

1996 ◽  
Vol 11 (11) ◽  
pp. 2790-2794 ◽  
Author(s):  
B. S. B. Karunaratne ◽  
R. J. Lumby ◽  
M. H. Lewis
Keyword(s):  
Optical Properties ◽  
Thermal Properties ◽  
Rare Earth ◽  
Mechanical And Thermal Properties ◽  
Silicon Nitrides ◽  
Sintering Atmosphere ◽  
Oxidation Reduction ◽  
Reduction Mechanisms ◽  
First Time ◽  
Rare Earth Doped

A new phenomenon in the field of Sialon ceramics is reported which may lead to applications based on their optical or electronic properties in combination with their mechanical and thermal properties. For the first time a colored α′-Sialon ceramic has been synthesized, with relatively high optical transparency by careful control of the sintering atmosphere, and adding suitable rare earths as stabilizing cations. This compares with normal Sialons and silicon nitrides which are grey-black in color and are opaque. Oxidation/reduction mechanisms have been identified as an influence on the valence of the stabilizing cation, which is responsible for the unusual optical properties.

scholarly journals Magnetic mineralogy of Variscan granites from northern Portugal: an approach to their petrogenesis and metallogenic potential

2020 ◽  
Vol 18 ◽  
pp. 1-20
Author(s):  
C. Cruz ◽  
H. Sant'Ovaia ◽  
F. Noronha
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Behavior ◽  
Redox Conditions ◽  
Magnetic Mineralogy ◽  
Magma Genesis ◽  
Northern Portugal ◽  
Hydrothermal Deposits ◽  
Variscan Granites ◽  
Redox History

Northern Portugal is characterized by the occurrence of numerous W hydrothermal deposits spatially associated with granites. The primary goal of this work is to establish a relationship between the magnetic behavior of thegranites and the redox conditions during magma genesis, as this can influence the occurrence of mineralizations, namely of W (Mo). To this end, the magnetic mineralogy of the granites of the Lamas de Olo Pluton, a posttectonic pluton in northern Portugal, with associated W (Mo) occurrences was characterized and compared with the magnetic mineralogy of other post-tectonic Variscan plutons. This pluton is composed of different biotite granites: Lamas de Olo, Alto dos Cabeços and Barragem. To better characterize its magnetic behavior, differentanalytical techniques that complement previous magnetic susceptibility studies were performed. The magnetic mineralogy of Lamas de Olo Pluton was then compared with other post-tectonic Variscan plutons such as the Vila Pouca de Aguiar, Peneda-Gerês and Lavadores-Madalena plutons. The presence of magnetite in some of these granites is important because it points to melt-oxidized conditions not commonly found in Iberian Variscan granites. Our study shows that granite areas where magnetite and/or magnetite/ilmenite coexist are important targets for W (Mo) mineralizations. The results indicate that a few plutons have granites with a complex redox history which leads to the formation of magnetite and ilmenite.

scholarly journals The Synthesis of Organophosphorus Compounds from Phosphine and Alcohols in the Presence of Quinones and Redox Polymers on their Basis

2012 ◽  
Vol 14 (3) ◽  
pp. 191 ◽  
Author(s):  
B.A. Mukhitdinova ◽  
E.E. Ergozhin ◽  
G.S. Polimbetova ◽  
A.K. Borangazieva
Keyword(s):  
Phosphoric Acid ◽  
Organophosphorus Compounds ◽  
Synergetic Effect ◽  
Phosphorous Acid ◽  
Molecular Iodine ◽  
Aliphatic Alcohols ◽  
Redox Polymers ◽  
Oxidation Reduction ◽  
Organic Solutions ◽  
First Time

<p>This article presents the synthesis of phosphoric acid esters from phosphoric hydrogen РН3 and aliphatic alcohols. The process is based on the oxidation of phosphine by quinones and redox polymers on the basis of mono- and disubstituted quinoid derivatives of monoethanolamine vinyl ether. Molecular iodine is used as a catalyst. Two-, three-, four- and multicomp onent systems are studied in order to determine optimal conditions of the oxidation of phosphine quinones and repoxpolymers on their basis. The rate and selectivity of reaction were monitored by the absorption of РН<sub>3</sub>. As alcohols used aliphatic alcohols: BuOH, PrOH, EtOH, MeOH. Organophosphorus compounds were analyzed by a chromatographic method. It was established that alcohol solutions of individual components of reactionary system (quinones, redox ionites or iodine) are characterized by a low activity in relation to phosphine. Organophosphorus compounds are formed in insignificant quantities. In the mixed alcohol<br /> solution of benzoquinone takes place PH<sub>3</sub> oxidation forming trialkylphosphates. Conversion of phosphine constitutes 80-100%. Increasing the concentration of reagents of catalytic system has a positive effect on the process as a whole. Similar patterns were obtained when redox monomers and polymers on the base of quinones in the presence of iodine were used as oxidants. Esters of phosphoric acid – dialkylphosphites and esters of phosphorous acid – trialkylphosphates were identified as organophosphorus compounds. By selecting a redox agent in a zone of the catalysis it is possible to direct process in the desirable direction. The most activity in the oxidation of phosphine by iodine-alcohol solutions of quinoid monomers and polymers, is exhibited by 2-[N-(2-vinyloxy) ethyl]amino-NQ and polymer on their basis. Results of our experiments and literature data on oxidation-reduction processes with participation of iodine and quinones in organic solutions allowed to propose the separate oxidation-reduction mechanism of formation of organophosphorus compounds. In investigated multicomponent systems, the synergetic effect is manifested which is reached at the expense of distribution of oxidation-reduction functions among iodine, quinones and its derivatives. In this report, for the first time, it is established reactionary ability of quinones and redox ionites on their basis in an oxidizing alkoxylation of phosphine to valuable esters of acids of phosphorus. Reaction can be used for purification of exhaust and technological gases from phosphine and its utilization.</p>

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