Search results for "melting"
showing 10 items of 238 documents
Timing of subduction and exhumation in a subduction channel: Evidence from slab melts from La Corea Mélange (eastern Cuba)
2011
article i nfo High pressure igneous rocks (tonalites), generated by partial melting of subducted basaltic rocks accreted to the mantle wedge, are present in the La Corea serpentinite-matrix melange (eastern Cuba) as centimeter- to meter-sized blocks and as concordant to crosscutting veins within high-pressure parent amphibolite blocks. The slab melts have adakitic signatures, in agreement with formation after partial melting of metabasite. Thermobarometric calculations indicate 620-680 °C and 13-15 kbar during crystallization of tonalites and down to 250-300 °C, 6 kbar during retrogression, indicating counter-clockwise P-T paths (hot subduction- cool exhumation). Free water required for mel…
Conformation of the umifenovir cation in the molecular and crystal structures of four carboxylic acid salts
2014
The umifenovir salts of maleic, salicylic, glutaric, and gentisic acid as well as the chloroform solvate of the salicylate were prepared. Single crystals of the five compounds were obtained and their molecular and crystal structures determined by X-ray diffraction. In each structure the conformation of phenyl ring with respect to the indole group of the umifenovir moiety is different. The water solubility and melting points of the studied umifenovir salts have been determined.
U-Pb data on zircons for the thermal peak of metamorphism in the Variscan Odenwald, Germany
1995
U-Pb data are presented for zircons from metamorphic rocks of the crystalline Odenwald that comprises part of the Mid-German Crystalline Rise. The Odenwald can be divided into four principal domains with different magmatic and metamorphic histories on the basis of published structural and petrological data and the presented ages. In the eastern (Boll-stein) Odenwald the metasedimentary rocks contain zircons derived from basement rocks that exceed 2.2 Ga in age. The intrusion of granitic magmas into these metasedimentary rocks took place before or close to the end of the thermal peak of metamorphism at 375 ± 5 Ma ago. Rapid uplift of the Bollstein Odenwald occurred at about 320 Ma bp, later …
Multi-chronometric ages and origin of Archaean tonalitic gneisses in Finnish Lapland: A case for long crustal residence time
1984
The Tojottamanselka gneisses of the Koitelainen region, northern Finland, have been dated by the Sm-Nd and the common Pb methods. The Sm-Nd data of seven samples from a small area (100 m × 100 m) define an isochron ofT=3.06±0.12 (2σ) Ga, with correspondingINd=0.50848±9 (2σ), oreNd(T)=−3.7±1.8. This age is in good agreement with the zircon U-Pb discordia age (3.1 Ga) reported by Kroner et al. (1981) and is interpreted as the time of magmatic emplacement. The distinctly negativeeNd(T) value is found for the first time for Archean tonalitic gneisses and implies derivation of these magmas by remelting of continental material with a long (200–500 Ma) crustal residence time. A few samples, on the…
Comparison of two melting range analysis methods with lactitol monohydrate
2001
Abstract In pharmacopoeia, the melting point is determined by a standard method with a melting point instrument. The melting point can also be determined with differential scanning calorimetry (DSC). In this study, the standard method and DSC method are compared for determining the melting range of lactitol monohydrate. The effect of initial temperature, grinding, and drying on the melting range of different lactitol monohydrate samples was studied by a melting point instrument. The melting point and melting enthalpy of the stable form of lactitol monohydrate was identified by DSC. The statistical analysis of the results is based on a t-test. All studied variables had a small effect on the …
Evaluation of viscoelastic constants of metallic materials by laser-ultrasonics at elevating temperature
2002
The main objective of this study is the determination of elastic moduli and viscosity coefficients of metals at elevating temperature up to melting point. More specifically, it involves the analysis of the propagation of acoustic waves generated and detected simultaneously by laser-ultrasonic for the measurement of longitudinal and shear velocities. This preliminary work primarily concerns Tin (Sn) metal known for its low melting point and attenuation coefficient.
Laser-ultrasonics: a non-contact method to link the acoustic attenuation to metal damping properties up to the melting point
2004
The objective of this work is to describe the viscoelastic behavior of metals up to their melting temperature by measuring the velocity and the attenuation of ultrasonics waves. For that purpose, a technique called laser-ultrasonics has been optimized for the high temperature domain and the solid to liquid transition. This paper is especially applied to the viscoelastic characterization of tin, from room temperature up to the melting point.
Interpretation of Structures and Fabrics Recognition and Interpretation of Fabric Patterns in Outcrop
1990
High-grade gneisses with a long and complex history have a finite ‘memory’ of past events. This memory is formed by fabric elements such as foliations, lineations, folds, mineral assemblages, boudins and sequences of intrusion. One of the aims of a geologist is to tap this memory as effectively as possible. The memory of rocks, however, is rather inadequate in that it is partly destroyed by the same events which produce the fabric elements that are recorded (Williams, 1983). Strong deformation erases older fabric elements; intrusions, recrystallisation and partial melting do the same (Figs. 1.1; 4.1). One of the purposes of this manual is to help geologists working in high-grade gneiss terr…
Numerical and experimental study of liquid metal stirring by rotating permanent magnets
2018
In this work, we study liquid gallium stirring by rotating permanent magnets. We demonstrate possibility of easily creating different flow patterns by rotating permanent magnets, which can be industrially important for controlling heat and mass transfer processes in the system. Unlike the typical approach of simulating magnet rotation as a transient problem and time-averaging the Lorentz forces, we solve the magnet rotation as a harmonic (frequency domain) problem, which leads to forces equal to time-averaged ones and decreases the simulation time considerably. Numerical results are validated using qualitative flow structure results from the neutron radiography visualization of tracer parti…
Feasible glass‐melting process assisted by microwaves
2019
[EN] The advantages of microwave (MW) energy processing have been verified in the sintering of a ceramic frit at a pre-industrial scale. The challenge of achieving high temperature using MW energy at such dimensions was overcome and a mix of natural raw materials was heated until its fluxing point. Changes in dielectric properties of the raw materials mix were also measured in situ with the increase in temperature, being in accordance to thermal processes of a conventional heating process. The properties of the resulting ceramic frit were compared with the same frit obtained by the conventional sintering method. Both frits showed similar thermal behavior regarding DTA-TGA, heating microscop…