On the melt differentiation in the intermediate chamber (by the example of differentiated intrusives of the western slope of the Southern Urals)

The article provides materials on the analysis of the chemical composition of silicates and aluminosilicates that make up the differentiated body of the Misaelga complex, which made it possible by calculation methods to restore the thermobaric parameters of crystallization of the melt in the intermediate chamber. The presence of high-temperature (1472 ºC) intratelluric olivine crystals characterizing the process of magma generation in the mantle and olivine crystallizing under the conditions of the intermediate chamber (1050–1183 ºC) has been established. The calculated crystallization temperature of pyroxenes indicates that they crystallized together with olivine from the bulk of the rocks, and the established variations in the P–T parameters (T = 950–1045 ºC, P = 4.0–7.4 kbar) for plagioclase and amphibole complete the quantitative characteristics of high-temperature melt crystallization processes. It is shown that the calculated Р–Т parameters of the crystallization of the melt that formed the intrusive massif make it possible to classify its ultrabasic horizon as picrite complexes of the second type that we identified earlier. Modeling of the crystallization process carried out using two models – according to the algorithm of H.D. Nathan and K.K. Van Kirk and the software product KOMAGMAT – made it possible to establish that the most probable mechanism for the formation of a differentiated body of the Misaelga complex was directional crystallization with gravitational deposition of olivine at the initial stages of the formation of the massif.

Defects of diamond crystal structure as an indicator of crystallogenesis

Based on the study of a representative collections of diamonds from diamondiferous formations of the Urals and deposits of the Arkhangelsk and Yakutian diamond provinces, we established patterns of zonal and sectoral distribution of crystal structure defects in crystals of different morphological types, identified the specifics of crystals formed at different stages of crystallogenesis and performed a comprehensive analysis of constitutional and population diversity of diamonds in different formations. We identified three stages in the crystallogenesis cycle, which correspond to normal and tangential mechanisms of growth and the stage of changing crystal habit shape. At the stage of changing crystal habit shape, insufficient carbon supersaturation obstructs normal growth mechanism, and the facets develop from existing surfaces. Due to the absent stage of growth layer nucleation, formation of new {111} surfaces occurs much faster compared to tangential growth mechanism. This effect allows to explain the absence of cuboids with highly transformed nitrogen defects at the A-B1 stage: they have all been refaceted by a regenerative mechanism. Based on the revealed patterns, a model of diamond crystallogenesis was developed, which takes into account the regularities of growth evolution, thermal history and morphological diversity of the crystals. The model implies the possibility of a multiply repetitive crystallization cycle and the existence of an intermediate chamber; it allows to explain the sequence of changes in morphology and defect-impurity composition of crystals, as well as a combination of constitutional and population diversity of diamonds from different geological formations.

Y. S. Hu, H. J. Wei, B. Yu, O. X. Yang, J. Wang, J. Wu. Research on the vapor injection of two-stage rotary compressor / trans. from Engl. M. A. Fedorova

In order to understand the vapor injection flow characteristics of two-stage rotary compressor in the course of compression, a mathematical model based on mass conservation equation, energy equation and thermodynamic identity was established and proved by P-V diagram testing results. Some useful conclusions about pressure in the intermediate chamber and mass flow of vapor injection in the course of compression were also given out. The results show that, gas backflow between the intermediate chamber and the vapor injection channel is an important defection of two-stage rotary compressor which can be solved by the application of injection valve in vapor injection channel. The injection valve can obviously reduce the gas backflow and the power loss in the course of compression while increasing the pressure fluctuation in the intermediate chamber. Experiments show that the COP of two-stage rotary compressor with the injection valve increased by over 2% in ASHRAE/T working condition.

Numerical calculation and experimental study on friction and lubrication of Stirling engine piston ring

To solve the practical problem of Stirling engine piston ring, numerical model on friction and lubrication were established based on average Reynolds equation theory. Numerical calculation results show: piston rings are in the mixed lubrication state which gas lubrication film and micro-convex body contact existing simultaneously; contact pressure is 2 orders of magnitude less than gas film pressure; contact pressure is approximately linearly related to mean gas pressure. Simulated test rig was built and experimental results show: high-pressure working gas leak to intermediate chamber through piston rings, and the pressure of intermediate chamber drops sharply at lowest pressure of circulation; piston ring wear increases when rotational speed or working pressure increase. The accuracy of numerical model was proved by experimental phenomena and test data.

JUSTIFICATION OF PRINCIPAL DIAGRAM AND STUDY OF THE OPERATING CYCLE OF VOLUMETRIC HYDROPERCUSSIVE MECHANISM

The approaches to justification of design diagrams of volumetric hydropercussive machines are presented. Simulation models of hydraulic impact systems are constructed and investigated. It is found that the diagram with an intermediate chamber allows decreasing peak pressure in the idle stroke chamber by two times, compared with the diagram without an intermediate chamber. It is concluded that hydropercussive machine with an elastic valve and intermediate chamber would hardly decrease the velocity of striking part in the end of power stroke.

Geological structure and petrology of the Nizhne-Sinyachikhinsky granitoid massif (Alapayevsk-Sukhoi Log porphyry copper zone, the Middle Urals)

Research subject. The geological structure and rock composition of the Nizhne-Sinyachikhinsky plagiogranite massif, which is part of the Alapaevsk-Sukholozhsky zone, is promising for the Cu(Au,Mo)-porphyric mineralization type, were studied. The aim was to determine the formation features of these rocks and compare them with the productive granitoids of Ural porphyry deposits of similar age. Materials and methods. The mineral composition of the rocks was determined using a JEOL JSM 6790LV scanning electron microscope with an INCA Energy 450 X-Max 80 EDS spectrometer and a CAMECA SX-100 electron microprobe analyser. The rock composition was obtained by X-ray fluorescence spectrometry on a SRM-35 and XRF-1800 spectrometers with the titrimetric determination of FeO. The concentrations of rare and rare-earth elements were determined on an ELAN 9000 inductively coupled plasma mass spectrometer at the Geoanalitik Center for Collective Use of the Ural Branch of the Russian Academy of Sciences. Results. For the first time, an early tonalite-plagiogranite series was identified in the structure of the massif. This series is represented by tonalites of the hypabyssal appearance, broken through by the dikes of plagiogranite-porphyry. It was shown that the separation of plagiogranite-porphyry melts from magmas of the mafic composition occurred at the base of the island-arc construction, and their crystallisation was carried out in an intermediate chamber at a pressure of 1.8–2.3 kbar. In contrast, the plagiogranites of the main phase of the massif were separated from the parent melt in an intermediate chamber located at the level of the upper crust, and their crystallisation occurred at a pressure of 1.5–2.0 kbar. Conclusions. A comparison of the main phase plagiogranites and the isolated early-series plagiogranite-porphyry indicates their similar composition, as well as their similarity in age with the granitoids of the Southern Urals, productive in terms of the porphyry mineralisation type. The concentrations of F, Cl and S in the apatites and amphiboles of the rocks under study is an argument in favour of their belonging to andesitoid formations that are productive in terms of the Cu (Au)-porphyry mineralisation type. The absence of the sulphide mineralisation of this type can be explained by a more significant depth of rock formation and their erosion section.

A critical magma chamber size for volcanic eruptions

We present a model for a coupled magma chamber–dike system to investigate the conditions required to initiate volcanic eruptions and to determine what controls the size of eruptions. The model combines the mechanics of dike propagation with internal chamber dynamics including crystallization, volatile exsolution, and the elastic response of the magma and surrounding crust to pressure changes within the chamber. We find three regimes for dike growth and eruptions: (1) below a critical magma chamber size, eruptions are suppressed because chamber pressure drops to lithostatic before a dike reaches the surface; (2) at an intermediate chamber size, the erupted volume is less than the dike volume (“dike-limited” eruption regime); and (3) above a certain chamber size, dikes can easily reach the surface and the erupted volume follows a classic scaling law, which depends on the attributes of the magma chamber (“chamber-limited” eruption regime). The critical chamber volume for an eruption ranges from ∼0.01 km3 to 10 km3 depending on the water content in the magma, depth of the chamber, and initial overpressure. This implies that the first eruptions at a volcano likely are preceded by a protracted history of magma chamber growth at depth, and that the crust above the magma chamber may have trapped several intrusions or “failed eruptions.” Model results can be combined with field observations of erupted volume, pressure, and crystal and volatile content to provide tighter constraints on parameters such as the eruptible chamber size.

Conceptual Design of an Ex-Vessel Melt Cooling Device

A helical ex-vessel cooling device is being designed and evaluated to insure retention of the molten corium that may discharge from the failed lower head of a reactor pressure vessel (RPV) during postulated severe accidents of a light water reactor. This conceptual design consists of four functional parts located in the reactor cavity, including an intermediate chamber for temporary retention of corium, an helical channel for corium spreading, cooling pipes embedded in the channel wall and venting system. The heat flux profile and steam generation along the cross section of the spreading channel T are analyzed under several conservative assumptions. The results show the melt coolability is achievable even under Benrenson film boiling regime.

ELECTROLYTIC REMOVAL OF HEAVY METALS IONS FROM MURIATIC SOLUTIONS

The results of research on the electrochemical processing of acidic regeneration solutions containing heavy metals ions are presented. The use of a three-cell electrolyzer makes it possible to efficiently extract zinc, copper and nickel ions from muriatic solutions and to concentrate hydrochloric acid in the cell’s intermediate chamber. The paper studies the dependence of the current yield of heavy metals on the concentration of hydrochloric acid, the initial concentration of heavy metals in the cathode chamber, the duration of electrolysis and the concentration of hydrochloric acid in its concentrating zone. The yield of copper and zinc decreases with increasing of acidity in the initial solutions and in the intermediate chamber of the cell. The current yield of nickel is determined to be little depended on the initial concentration of hydrochloric acid. The results on the concentration of hydrochloric acid, depending on the duration of electrolysis, the initial concentration of acid and heavy metals in the catholyte are presented. Bibl. 9, Fig. 9.

Secondary Electron Detector with the Unipotential Lens Structure for Variable Pressure/Environmental SEM

To extend capabilities of classic instruments toward the VP/E technique, authors designed the vacuum-detector system in the form of a simple attachment, which can be mounted to a classic SEM, without changes in its original structure. The main part of the system is the vacuum and detection head, combining the intermediate chamber and electron detectors of chosen kinds. Authors investigate the SE detector showing the unipotential lens structure to find optimum solution for a wide range of gas pressures from high vacuum to pressures exceeding 10 mbar.