1,720,970 research outputs found
High Temperature Decomposition of Methane on Quartz Pellets
Full text linkThis work has shown that pure methane, when exposed to quartz at a temperatures of 900°C and 1000°C, cracks and deposits carbon at a near constant rate. The deposition rates for the individual temperature levels were shown to differ by a factor of approximately 7, where experiments at 1000°C showed the highest rate of deposition and those at 900°C the lowest.
The surfaces of the samples showed a definite increase after the treatment. While not definite, there were signs that surface area could be a function of deposited carbon mass. There were not observed any weight increase on the sample treated at 700°C, and
only small amounts on the sample at 800°C, indicating a cut-off temperature for the reaction in this interval
Modelling of gas-solid reactions - Usage of industrial off-gas for pre-reduction of manganese ores
Full text linkThe traditional way of making manganese alloys are by reduction of different manganese oxides, iron oxides and silicon dioxide in a standalone electric furnace. That being said, manganese alloy producing companies may consider the implementation of a prereduction unit which will pre-reduce the ore before entering the electric furnace reducing the overall electrical consumption per ton alloy produced. How well the prereduction unit will contribute to the reduction of electrical consumption have previously been found to rely heavily on ore content. At this point, we should implement a reliable model which describes the process at hand inside a theoretical pretreatment unit.
An established framework describing the gaseous reduction of manganese oxide inside a prereduction unit has been made which relies on a continuous model taking the most important gas-solid reaction related phenomena into account. The model proved to be both fast and resilient. Several relevant cases were tested on the implemented continuous model to see how it performed. Some flaws were found. These were related to heat transfer and different kinetic parameters such as rate constants. There still exists some industrially relevant questions that go unanswered concerning prereduction. Here, our model can be used to assist further work and decisions on the matter
High Temperature Decomposition of Methane on Quartz Pellets
No full textThis work has shown that pure methane, when exposed to quartz at a temperatures of 900°C and 1000°C, cracks and deposits carbon at a near constant rate. The deposition rates for the individual temperature levels were shown to differ by a factor of approximately 7, where experiments at 1000°C showed the highest rate of deposition and those at 900°C the lowest.
The surfaces of the samples showed a definite increase after the treatment. While not definite, there were signs that surface area could be a function of deposited carbon mass. There were not observed any weight increase on the sample treated at 700°C, and
only small amounts on the sample at 800°C, indicating a cut-off temperature for the reaction in this interval
Modelling of gas-solid reactions - Usage of industrial off-gas for pre-reduction of manganese ores
No full textThe traditional way of making manganese alloys are by reduction of different manganese oxides, iron oxides and silicon dioxide in a standalone electric furnace. That being said, manganese alloy producing companies may consider the implementation of a prereduction unit which will pre-reduce the ore before entering the electric furnace reducing the overall electrical consumption per ton alloy produced. How well the prereduction unit will contribute to the reduction of electrical consumption have previously been found to rely heavily on ore content. At this point, we should implement a reliable model which describes the process at hand inside a theoretical pretreatment unit.
An established framework describing the gaseous reduction of manganese oxide inside a prereduction unit has been made which relies on a continuous model taking the most important gas-solid reaction related phenomena into account. The model proved to be both fast and resilient. Several relevant cases were tested on the implemented continuous model to see how it performed. Some flaws were found. These were related to heat transfer and different kinetic parameters such as rate constants. There still exists some industrially relevant questions that go unanswered concerning prereduction. Here, our model can be used to assist further work and decisions on the matter
Solubility of Carbon and Nitrogenin the Silicon Rich Part of theSi–C–N–B-System
No full textPhD i materialteknologiPhD in Materials Technolog
Solubility of Carbon and Nitrogenin the Silicon Rich Part of theSi–C–N–B-System
Full text linkPhD i materialteknologiPhD in Materials Technolog
The Interactions of Carbon and Nitrogen in Liquid Silicon
No full textThe interactions between carbon and nitrogen in liquid silicon have been studied experimentally. High purity silicon was melted in silicon nitride crucibles under an Ar atmosphere with a graphite slab inserted in the crucible prior to melting as a carbon source. The system was thus simultaneously equilibrated with Si3N4 and SiC. Samples were extracted in the temperature range 1695–1798 K and analyzed using Leco
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
