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References Y. Bottinga 1969 Calculated fractionation factors for carbon and hydrogen isotope exchange in the system calcite-carbon dioxide-graphite
Abstract
The catalytic and accelerating effects of three coal-burning additives (CBA) on the burning of graphite were studied with the help of thermogravimetric (TG) analysis. The kinetic study on the catalytic oxidation of the graphite doped with CBA was carried out and the results were presented. The results show that the CBA can change the carbon oxidation/combustion course by catalytic action and change the activation energy, thus improving the combustion efficiency.
Abstract
Results of the investigations of deintercalation process in intercalation compounds graphite-SbCl5 and graphite-ICl are presented. It was found that sample mass losses have a step character that testifies to the discrete transition from one stage of graphite intercalation compounds to another. The increase in the rate of heating breaks the step character of mass loss dependence on temperature and intensive mass losses occur without stage transitions.
Abstract
In this paper an attempt has been made to characterize the low grade calcareous graphite ore from Shivaganga region, India. By judicious combination of structural, thermal and chemical analytical techniques, the liberation size of graphite as well as estimation of minerals are determined to establish a feasible beneficiation process. This data show a good correlation. The ore consists of graphite, calcite and quartz as major minerals. The d-values and decomposition of calcite are found maximum at two size fractions i.e., +500 and below 90 microns. The TG and chemical analysis data on quantitative minerals estimation confirms that calcite significantly liberates below 90 micron size fraction and accounts for 60% calcite and 10% graphite minerals distribution. The DTA data show that calcite decomposes between 700–850°C and graphite starts combustion at 850°C. In view of this, to achieve calcite free graphite the ore needs to be calcined below 850°C and ground to 80% passing 75 micron size prior to flotation.
Abstract
The heat capacity obtained below 30 K for the tetramethylsilane monolayers, which are adsorbed either on graphite or on the (100) surface of MgO, is analyzed to investigate the vibrational properties. The 2-D Debye temperatures are approximately 60% of the Debye temperature of the bulk solid (γ -phase), reflecting the dimensionality of lattice vibrations. The contributions from the vibrations perpendicular to the surface as well as the librational motions are determined by fitting the experimental heat capacities. All the results are consistent with those obtained from the incoherent inelastic neutron scattering and the molecular dynamics simulation.
From the very beginning of the magnetotelluric (MT) studies two notions have been coupled to each other: the graphite as one of the causes of strong conductivity anomalies and tectonics. The graphitic formations of very low resistivity (< 10-1 Wm) are accumulated in the shear zones, thrust sheets, detachment horizon etc.\ and by this way they indicate the tectonics/paleotectonics which may not be indicated by other geophysical method so definitely. The author firstly surveys the manifestation of this phenomenon in case histories of the literature, then illustrates it by own very detailed study carried out on the Transdanubian crustal conductivity anomaly (TCA). The material of the conductor and their possible relation to the seismicity of the area will also be demonstrated by the TCA anomaly. In the closing chapters the origin of the graphite and its accumulation in the shear zones is discussed including the role of the (geothermal) water.
Abstract
A computerized adiabatic calorimeter for heat capacity measurements in the temperature range 80–400 K has been constructed. The sample cell of the calorimeter, which is about 50 cm3 in internal volume, is equipped with a platinum resistance thermometer and surrounded by an adiabatic shield and a guard shield. Two sets of 6-junction chromel-copel thermocouples are mounted between the cell and the shields to indicate the temperature differences between them. The adiabatic conditions of the cell are automatically controlled by two sets of temperature controller. The reliability of the calorimeter was verified through heat capacity measurements on the standard reference material α-Al2O3. The results agreed well with those of the National Bureau of Standards (NBS): within 0.2% throughout the whole temperature region. The heat capacities of high-purity graphite and polystyrene were precisely measured in the interval 260–370 K by using the above-mentioned calorimeter. The results were tabulated and plotted and the thermal behavior of the two materials was discussed in detail. Polynomial expressions for calculation of the heat capacities of the two substances are presented.
rise to non-equilibrium conditions and the formation of novel structures [ 1 , 2 ]. Of particular interest are impact diamonds ( Fig. 1 ) and diamond-like nanostructures that form during the shock compression of graphitic materials. Fig. 1. Impact
. , Buahom P. , Saniei M. , Kenig S. , Parka C. B. , Lee S. E. ( 2016 ), Reducing Thermal Conductivity of Polymeric Foams with High Volume Expansion Made From Polystyrene/Expanded Graphite . SPE ANTE, 1870 – 1882 . [8
Introduction The Pebble Bed Modular Reactor (PBMR) is a High Temperature Gas Cooled Reactor (HTGR) design that incorporates numerous inherent passive safety features. Graphite is an important material of construction for the
