Fluorapophyllite-(Cs), CsCa₄(Si₈O₂₀)F(H₂O)₈, a new apophyllite-group mineral from the Darai-Pioz Massif, Tien-Shan, Northern Tajikistan

Fluorapophyllite-(Cs) (IMA 2018-108a), ideally CsCa4(Si8O20)F(H2O)(8), is an apophyllite-group mineral from the moraine of the Darai-Pioz glacier, Tien-Shan, Northern Tajikistan. Associated minerals are quartz, pectolite, baratovite, aegirine, leucosphenite, pyrochlore, neptunite, fluorapophyllite-(K), and reedmergnerite. Fluorapophyllite-(Cs) is a hydrothermal mineral. It is colorless and has a vitreous luster and a white streak. Cleavage is perfect; it is brittle and has a stepped fracture. Mohs hardness is 4.5-5. D-meas. = 2.54(2) g/cm(3), D-calc. = 2.513 g/cm(3). Fluorapophyllite-(Cs) is unixial (+) with refractive indices (lambda = 589 nm) omega = 1.540(2), epsilon = 1.544(2). It is non-pleochroic. Chemical analysis by electron microprobe gave SiO2 48.78, Al2O3 0.05, CaO 22.69, Cs2O 10.71, K2O 1.13, Na2O 0.04, F 1.86, H2Ocalc. 14.61, -O=F2 -0.78, sum 99.09 wt.%; H2O was calculated from crystal-structure analysis. The empirical formula based on 29 (O + F) apfu, H2O = 8 pfu, is (Cs0.75K0.24)Sigma(0.99)(Ca3.99Na0.01)Sigma(4)(Si8.01Al0.01)Sigma 8.02O20.03F0.97(H2O)8, Z = 2. The simplified formula is (Cs,K)(Ca,Na)(4)(Si,Al) 8 O20F(H2O)(8). Fluorapophyllite-(Cs) is tetragonal, space group P4/mnc, a 9.060(6), c 15.741(11) angstrom, V 1292.10(19) angstrom(3). The crystal structure has been refined to R-1 = 4.31% based on 498 unique (F-o > 4 sigma F) reflections. In the crystal structure of fluorapophyllite-(Cs), there is one [4] T site occupied solely by Si,,T-O. = 1.615 angstrom. SiO4 tetrahedra link to form a (Si8O20)(8-)sheet perpendicular to [001]. Between the Si-O sheets, there are two cation sites: A and B. The A site is coordinated by eight H2O groups [O(4) site], A-O(4) = 3.152(4) angstrom; the A site contains Cs(0.75)K(0.24)A(0.01 square 0.01), ideally Cs apfu. The Cs-O bond length of 3.152 angstrom is definitely larger than the K-O bond length of 2.966-2.971 angstrom in fluorapophyllite-(K), KCa4(Si8O20)F(H2O)8. The [7]B site contains Ca3.99Na0.01, ideally Ca-4 apfu; < B-phi > = 2.417 angstrom (phi = O, F, H2O). The Si-O sheets connect via A and B polyhedra and hydrogen bonding; two H atoms have been included in the refinement. Fluorapophyllite-(Cs) is isostructural with fluorapophyllite-(K). Fluorapophyllite-(Cs) is a Cs-analogue of fluorapophyllite-(K)

Patynite, NaKCa4[Si9O23], a New Mineral from the Patynskiy Massif, Southern Siberia, Russia

The new mineral patynite was discovered at the massif of Patyn Mt. (Patynskiy massif), Tashtagolskiy District, Kemerovo (Kemerovskaya) Oblast\u2019, Southern Siberia, Russia. Patynite forms lamellae up to 1 0.5 cm and is closely intergrown with charoite, tokkoite, diopside, and graphite. Other associated minerals include monticellite, wollastonite, pectolite, calcite, and orthoclase. Patynite is colorless in individual lamellae to white and white-brownish in aggregates. It has vitreous to silky luster, white streaks, brittle tenacity, and stepped fractures. Its density measured by flotation in Clerici solution is 2.70(2) g/cm3; density calculated from the empirical formula is 2.793 g/cm3. The Mohs\u2019 hardness is 6. Optically, patynite is biaxial (\u2013) with \u3b1 = 1.568(2), \u3b2 = 1.580(2), and \u3b3 = 1.582(2) (589 nm). The 2V (measured) = 40(10) and 2V (calculated) = 44.1. The Raman and IR spectra shows the absence in the mineral of H2O, OH\u2013, and CO32\u2013 groups and B\u2013O bonds. The chemical composition is (electron microprobe, wt.%): Na2O 3.68, K2O 5.62, CaO 26.82, SiO2 64.27, total 100.39. The empirical formula based on 23 O apfu is Na1.00K1.00Ca4.02Si8.99O23. Patynite is triclinic, space group P\u20131. The unit-cell parameters are: a = 7.27430(10), b = 10.5516(2), c = 13.9851(3) \uc5, \u3b1 = 104.203(2)\ub0, \u3b2 = 104.302(2)\ub0, \u3b3 = 92.0280(10)\ub0, V = 1003.07(3) \uc53, Z = 2. The crystal structure was solved by direct methods and refined to R1 = 0.032. Patynite is an inosilicate with a new type of sextuple branched tubular chain [(Si9O23)10\u2013] with an internal channel and [(Si18O46)20\u2013] as the repeat unit. The strongest lines of the powder X-ray diffraction pattern [dobs, \uc5 (I, %) (hkl)] are: 3.454 (100) (2-1-1), 3.262 (66) (2-1-2), 3.103 (64) (02-4), 2.801 (21), 1.820 (28) (40-2). Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia with the registration number 5369/1

Refractory Coatings of C-Me-Si and C-Me-B-Si Systems for Protection of Carbon Materials (CM)

The three-zoned structure of the coatings for protection from high-temperature oxidation of carbon materials (CM) was grounded. The kinetic of formation and phase composition of diffusion coating C-Me-Si and C-Me-B-Si (Me = Ti, Zr or Hf) systems formed on CM (graphite and carbon/carbon materials) have been studied. The coating on CM received by using sequential metallization, boron- and silicium- deposition from dispersive solid-phased media. The rate of formation coatings of C-Me-Si by metallization and Si-deposition on CM decreases on the line : Ti--Zr--Hf, and the formation carbide layers MeC by diffusion metallization CM describes linear-parabolic law have been shown. The velocity of boron diffusion of the "CM - MeC layer" compositions is very little and it is increased on the line : Ti--Zr--Hf insignificantly. The formation of MeB2 layer at the boriding are decreased of the velocity of siliciding. The coating proposed hase three-zoned structure formed by compounds of C-Me-Si or C-Me-B-Si systems and intended for protection of CM from high-temperature oxidation (T [MATH] 1400°C). The laws of phase form and destruction at high-temperature oxidation in air for these coatings are investigated

The rhetoric of the political leaders of russia and the U.S.: A comparative analysis

The article represents the results of research into the role of intercultural communication, in the political discourse of Russia and the United States. This research project allowed the authors to obtain a large array of applied results on the state of the rhetoric of leading politicians in Russia and the US (from more than 150 sources) using linguistic and cultural comparative analyses. The presence of a scientific background and the methodological positions on various aspects of relations between Russia and the United States allowed the authors to carry out this study; the object of this was intercultural communication between politicians, whilst the subject was an analysis of general differences in Russian and American politicians' use of speech strategies and tactics, and their expressive means as a functional of political dialogue. The study of nationalcultural markers of speech strategies was considered by the authors, on the one hand, as specific mechanisms of politicians' verbal behavior, and on the other hand as applied problems which reflect the choice of expressive means used by American politicians, and which further reflects the presence of an ethnic component through which national values can be judged, such as the interests of Russia and USA, from the position of international cooperation. The use of discursive, communicative-pragmatic, and rhetorical methods allowed the authors to systematize the discursive-communicative strategies and tactics used by the participants in political dialogue between Russia and the United States, and allowed them to compare their national and cultural characteristics. © Editorial Board Polis (Political Studies)

Heat-Resistance and Phase Composition of Ti-Si Coatings on Niobium

A diffusion silicide coatings on refraotory under thermal shook. A prospective method of improving their durability in the formation of multi-component coatings. Ti is one of the widespread components of such coatings. In this work, process of simultaneous diffusion saturation of niobium by Ti and Si in powder mixtures has been investigated. The coatings can be divided into two basic types : Nb-Ti solid solutions and Nb and Ti silicides. The coatings of the first type obtained in Ti-Ti5Si3 powder mixtures. The complex silicide layers were observed in the packs with higher silicon activity (Ti5Si3 - TiSi and TiSi2-TiSi mixtures). The activities of Ti and Si have been shown to be principal controlling factores in coating phase in composition. The coatings allows to increase heat-resistance of the niobium and niobium alloys up to 2000°C (1,5 hour)

Influence of electrolyte on the zirconium electrolysis process for nuclear power engineering

The effect of welding method and technique on the HAZ microstructure in dissimilar welded joint of the type reactor vessel steel + deposited austenitic layer was investigated. The results of metallographic studies and bend tests of the welded joints are evidenced that the development of technology for weld repair of an anticorrosive coating with access to the base metal without subsequent high tempering is advisable on the basis of “buttered layer” technique by MMA welding with layer–by–layer controlled change in linear energy. This approach provides a uniform fine-grained microstructure at the overheat region of the HAZ. TIG welding with the filler wire and constant layer–by–layer linear energy also allows to refine overheat region microstructure. However, in this case, it is characterized by two types of structural heterogeneity caused by intense overheating of the base metal and diffusion of alloying elements and carbon.Досліджувався вплив способу зварювання на структуру металу зони термічного впливу (ЗТВ) у різнорідному зварному з’єднанні типу корпусна реакторна сталь + наплавлений аустенітний шар. Результати металографічних досліджень та випробувань на згин металу зварних з’єднань показали, що розробка технології ремонтної наплавки антикорозійного покриття з виходом в основний метал корпусу реактора без наступного його високого відпуску доцільна на основі техніки проміжного шару при зварюванні покритими електродами з пошаровою контрольованою зміною погонної енергії. Цей підхід забезпечує на ділянці перегріву ЗТВ однорідну дрібнозернисту структуру. Ручне аргонодугове зварювання з подачею присадки і пошарово незмінною погонною енергією також дозволяє подрібнити зерно на ділянці перегріву. Однак при цьому для неї є характерним два види структурної неоднорідності, пов’язані з інтенсивним перегрівом основного металу і дифузією легуючих елементів та вуглецю.Исследовалось влияние способа сварки на структуру металла зоны термического влияния (ЗТВ) в разнородном сварном соединении корпусная реакторная сталь + наплавленный аустенитный слой. Результаты металлографических исследований и испытаний на изгиб металла сварных соединений показали, что разработка технологии ремонтной наплавки антикоррозионного покрытия с выходом в основной металл корпуса реактора без последующего его высокого отпуска целесообразна на основе техники промежуточного слоя при сварке покрытыми электродами с послойным контролируемым изменением погонной энергии. Этот подход обеспечивает на участке перегрева однородную мелкозернистую структуру. Ручная аргонодуговая сварка с подачей присадки и послойно неизменной погонной энергией также позволяет измельчить зерно на участке перегрева. Однако при этом для него характерны два вида структурной неоднородности, связанные с интенсивным перегревом основного металла и диффузией легирующих элементов и углерода