Browsing by Subject "Iron"

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    A study of iron kinetics in normal and abnormal human subjects
    (1973) French, Terence John
    The work to be presented in this thesis took pl ace while I was working as a registrar in the department of radio-isotope diagnosis at Groote Schuur Hospital. During this period, I became interested in the ferrokinetic technique for attempting to quantitate normal and abnormal erythropoietis, and the possible development of these techniques so as to allow more accurate quantitation of the data. At the time the study started, the department was offering standard ferrokinetic investigations to aid in the diagnosis of abnormal haematological states. These studies did not, I felt, provide adequate information for the referring clinician, particularly in regard to ineffective erythropoietic activity.
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    Effect of base metal oxygen content and oxygen activity on mechanical properties of EN-GJL- GG - 26 Cu-Cr grey cast-iron heavy-duty crank cases
    (2025) Senyolo, Morokolo; Knutsen, Robert
    Grey cast iron is a type of cast iron named for its grey appearance due to the presence of graphite flakes in the material. It is widely used in engine components, because of its wide range of mechanical and physical properties, which include strong heat conductivity, vibration damping capabilities, and superior machinability. One of the key development trends for grey cast-iron applications is the need for increased tensile strength, which will allow higher peak engine pressure, that leads to more efficient combustion and lower emissions. This research investigates how the oxygen content and oxygen activity of the liquid EN-GJL-GG - 26 Cu-Cr Grey Cast Iron metal are affected by holding the metal for a duration of 0 to 24 hours in a closed furnace/inert atmosphere, and how the addition of reactive iron oxide from 0 to 0.2wt% affects the oxygen content and activity at the different holding duration, and what will be its impact on the graphite morphology and the resulting mechanical properties. This report has documented the rigorous experimental approach and parameter measurement protocols and has presented the results of all the relevant measurements which were collected with minimal experimental error. However, for the most part, the measurements have indicated a minimal effect of the process variables listed above on the behaviour of the grey iron. The spread in data measurement, as indicated on the graph plots, and the overlapping values means that in many instances definitive trends could not be recognised. However, some noteworthy findings are indicated below: Oxygen content and activity of the melt decrease with increasing holding time, with no clear relation between wt% FeO addition and resulting oxygen content and activity. Oxygen content and activity are directly proportional, the volume fraction of Type E graphite in microstructure increases with increasing wt%FeO addition, oxygen content and activity. The tensile strength and hardness are insignificantly affected by changes in wt%FeO additions, oxygen content and activity.
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    Strong-metal–support interaction by molecular design: Fe–silicate interactions in Fischer–Tropsch catalysts
    (Elsevier, 2012) Mogorosi, Ramoshibidu P; Fischer, Nico; Claeys, Michael; van Steen, Eric
    Metal–support interactions in the form of iron–silicate were investigated by an inverse approach, that is, modification of nano-sized iron oxide with surface silicate groups. The presence of surface silicate groups in the calcined catalyst precursor was confirmed using diffuse reflectance infra-red Fourier transform analysis. The genesis of the various iron phases in the presence of surface silicate groups after H2-activation and the Fischer–Tropsch synthesis was followed. The surface silicate groups are preserved after a hydrogen treatment at 350 C for 16 h, and these surface ligands are associated with the residual iron oxide phase, wüstite. During the Fischer–Tropsch synthesis, a-Fe is mostly converted into v-Fe5C2, whereas FeO is the main source for e-Fe2C. The activity per unit surface area of hexagonal carbide, eFe2C, is ca. 25% higher than that of v-Fe5C2. The presence of surface silicate ligands on e-Fe2C results in a further enhancement of the rate per unit surface area of e-Fe2C by a factor of ca. 3. This is being ascribed to the enhanced availability of hydrogen on the surface due to the presence of the surface silicate groups, which also results in an increase in the methane selectivity, a decrease in the olefin content and a decrease in formation of branched product compounds.